This is the start of the stable review cycle for the 4.9.75 release.
There are 39 patches in this series, all will be posted as a response
to this one. If anyone has any issues with these being applied, please
let me know.
Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
Anything received after that time might be too late.
The whole patch series can be found in one patch at:
kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
or in the git tree and branch at:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
and the diffstat can be found below.
thanks,
greg k-h
-------------
Pseudo-Shortlog of commits:
Greg Kroah-Hartman <[email protected]>
Linux 4.9.75-rc1
Kees Cook <[email protected]>
KPTI: Report when enabled
Kees Cook <[email protected]>
KPTI: Rename to PAGE_TABLE_ISOLATION
Borislav Petkov <[email protected]>
x86/kaiser: Move feature detection up
Jiri Kosina <[email protected]>
kaiser: disabled on Xen PV
Borislav Petkov <[email protected]>
x86/kaiser: Reenable PARAVIRT
Thomas Gleixner <[email protected]>
x86/paravirt: Dont patch flush_tlb_single
Hugh Dickins <[email protected]>
kaiser: kaiser_flush_tlb_on_return_to_user() check PCID
Hugh Dickins <[email protected]>
kaiser: asm/tlbflush.h handle noPGE at lower level
Hugh Dickins <[email protected]>
kaiser: drop is_atomic arg to kaiser_pagetable_walk()
Hugh Dickins <[email protected]>
kaiser: use ALTERNATIVE instead of x86_cr3_pcid_noflush
Borislav Petkov <[email protected]>
x86/kaiser: Check boottime cmdline params
Borislav Petkov <[email protected]>
x86/kaiser: Rename and simplify X86_FEATURE_KAISER handling
Hugh Dickins <[email protected]>
kaiser: add "nokaiser" boot option, using ALTERNATIVE
Hugh Dickins <[email protected]>
kaiser: fix unlikely error in alloc_ldt_struct()
Hugh Dickins <[email protected]>
kaiser: kaiser_remove_mapping() move along the pgd
Hugh Dickins <[email protected]>
kaiser: paranoid_entry pass cr3 need to paranoid_exit
Hugh Dickins <[email protected]>
kaiser: x86_cr3_pcid_noflush and x86_cr3_pcid_user
Hugh Dickins <[email protected]>
kaiser: PCID 0 for kernel and 128 for user
Hugh Dickins <[email protected]>
kaiser: load_new_mm_cr3() let SWITCH_USER_CR3 flush user
Hugh Dickins <[email protected]>
kaiser: enhanced by kernel and user PCIDs
Hugh Dickins <[email protected]>
kaiser: vmstat show NR_KAISERTABLE as nr_overhead
Hugh Dickins <[email protected]>
kaiser: delete KAISER_REAL_SWITCH option
Hugh Dickins <[email protected]>
kaiser: name that 0x1000 KAISER_SHADOW_PGD_OFFSET
Hugh Dickins <[email protected]>
kaiser: cleanups while trying for gold link
Hugh Dickins <[email protected]>
kaiser: align addition to x86/mm/Makefile
Hugh Dickins <[email protected]>
kaiser: tidied up kaiser_add/remove_mapping slightly
Hugh Dickins <[email protected]>
kaiser: tidied up asm/kaiser.h somewhat
Hugh Dickins <[email protected]>
kaiser: ENOMEM if kaiser_pagetable_walk() NULL
Hugh Dickins <[email protected]>
kaiser: fix perf crashes
Hugh Dickins <[email protected]>
kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER
Hugh Dickins <[email protected]>
kaiser: KAISER depends on SMP
Hugh Dickins <[email protected]>
kaiser: fix build and FIXME in alloc_ldt_struct()
Hugh Dickins <[email protected]>
kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE
Hugh Dickins <[email protected]>
kaiser: do not set _PAGE_NX on pgd_none
Dave Hansen <[email protected]>
kaiser: merged update
Richard Fellner <[email protected]>
KAISER: Kernel Address Isolation
Tom Lendacky <[email protected]>
x86/boot: Add early cmdline parsing for options with arguments
Neal Cardwell <[email protected]>
tcp_bbr: reset long-term bandwidth sampling on loss recovery undo
Neal Cardwell <[email protected]>
tcp_bbr: reset full pipe detection on loss recovery undo
-------------
Diffstat:
Documentation/kernel-parameters.txt | 8 +
Makefile | 4 +-
arch/x86/boot/compressed/misc.h | 1 +
arch/x86/entry/entry_64.S | 163 ++++++++--
arch/x86/entry/entry_64_compat.S | 8 +-
arch/x86/events/intel/ds.c | 57 +++-
arch/x86/include/asm/cmdline.h | 2 +
arch/x86/include/asm/cpufeatures.h | 4 +
arch/x86/include/asm/desc.h | 2 +-
arch/x86/include/asm/hw_irq.h | 2 +-
arch/x86/include/asm/kaiser.h | 141 +++++++++
arch/x86/include/asm/pgtable.h | 28 +-
arch/x86/include/asm/pgtable_64.h | 25 +-
arch/x86/include/asm/pgtable_types.h | 29 +-
arch/x86/include/asm/processor.h | 2 +-
arch/x86/include/asm/tlbflush.h | 74 ++++-
arch/x86/include/uapi/asm/processor-flags.h | 3 +-
arch/x86/kernel/cpu/common.c | 28 +-
arch/x86/kernel/espfix_64.c | 10 +
arch/x86/kernel/head_64.S | 35 ++-
arch/x86/kernel/irqinit.c | 2 +-
arch/x86/kernel/ldt.c | 25 +-
arch/x86/kernel/paravirt_patch_64.c | 2 -
arch/x86/kernel/process.c | 2 +-
arch/x86/kernel/setup.c | 7 +
arch/x86/kernel/tracepoint.c | 2 +
arch/x86/kvm/x86.c | 3 +-
arch/x86/lib/cmdline.c | 105 +++++++
arch/x86/mm/Makefile | 4 +-
arch/x86/mm/init.c | 2 +-
arch/x86/mm/init_64.c | 10 +
arch/x86/mm/kaiser.c | 454 ++++++++++++++++++++++++++++
arch/x86/mm/kaslr.c | 4 +-
arch/x86/mm/pageattr.c | 63 +++-
arch/x86/mm/pgtable.c | 12 +-
arch/x86/mm/tlb.c | 39 ++-
include/asm-generic/vmlinux.lds.h | 7 +
include/linux/kaiser.h | 52 ++++
include/linux/mmzone.h | 3 +-
include/linux/percpu-defs.h | 32 +-
init/main.c | 2 +
kernel/fork.c | 6 +
mm/vmstat.c | 1 +
net/ipv4/tcp_bbr.c | 5 +
security/Kconfig | 10 +
tools/arch/x86/include/asm/cpufeatures.h | 3 +
46 files changed, 1382 insertions(+), 101 deletions(-)
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Neal Cardwell <[email protected]>
commit 600647d467c6d04b3954b41a6ee1795b5ae00550 upstream.
Fix BBR so that upon notification of a loss recovery undo BBR resets
long-term bandwidth sampling.
Under high reordering, reordering events can be interpreted as loss.
If the reordering and spurious loss estimates are high enough, this
can cause BBR to spuriously estimate that we are seeing loss rates
high enough to trigger long-term bandwidth estimation. To avoid that
problem, this commit resets long-term bandwidth sampling on loss
recovery undo events.
Signed-off-by: Neal Cardwell <[email protected]>
Reviewed-by: Yuchung Cheng <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/ipv4/tcp_bbr.c | 1 +
1 file changed, 1 insertion(+)
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -847,6 +847,7 @@ static u32 bbr_undo_cwnd(struct sock *sk
bbr->full_bw = 0; /* spurious slow-down; reset full pipe detection */
bbr->full_bw_cnt = 0;
+ bbr_reset_lt_bw_sampling(sk);
return tcp_sk(sk)->snd_cwnd;
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Avoid perf crashes: place debug_store in the user-mapped per-cpu area
instead of allocating, and use page allocator plus kaiser_add_mapping()
to keep the BTS and PEBS buffers user-mapped (that is, present in the
user mapping, though visible only to kernel and hardware). The PEBS
fixup buffer does not need this treatment.
The need for a user-mapped struct debug_store showed up before doing
any conscious perf testing: in a couple of kernel paging oopses on
Westmere, implicating the debug_store offset of the per-cpu area.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/events/intel/ds.c | 57 +++++++++++++++++++++++++++++++++++----------
1 file changed, 45 insertions(+), 12 deletions(-)
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2,11 +2,15 @@
#include <linux/types.h>
#include <linux/slab.h>
+#include <asm/kaiser.h>
#include <asm/perf_event.h>
#include <asm/insn.h>
#include "../perf_event.h"
+static
+DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(struct debug_store, cpu_debug_store);
+
/* The size of a BTS record in bytes: */
#define BTS_RECORD_SIZE 24
@@ -268,6 +272,39 @@ void fini_debug_store_on_cpu(int cpu)
static DEFINE_PER_CPU(void *, insn_buffer);
+static void *dsalloc(size_t size, gfp_t flags, int node)
+{
+#ifdef CONFIG_KAISER
+ unsigned int order = get_order(size);
+ struct page *page;
+ unsigned long addr;
+
+ page = __alloc_pages_node(node, flags | __GFP_ZERO, order);
+ if (!page)
+ return NULL;
+ addr = (unsigned long)page_address(page);
+ if (kaiser_add_mapping(addr, size, __PAGE_KERNEL) < 0) {
+ __free_pages(page, order);
+ addr = 0;
+ }
+ return (void *)addr;
+#else
+ return kmalloc_node(size, flags | __GFP_ZERO, node);
+#endif
+}
+
+static void dsfree(const void *buffer, size_t size)
+{
+#ifdef CONFIG_KAISER
+ if (!buffer)
+ return;
+ kaiser_remove_mapping((unsigned long)buffer, size);
+ free_pages((unsigned long)buffer, get_order(size));
+#else
+ kfree(buffer);
+#endif
+}
+
static int alloc_pebs_buffer(int cpu)
{
struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
@@ -278,7 +315,7 @@ static int alloc_pebs_buffer(int cpu)
if (!x86_pmu.pebs)
return 0;
- buffer = kzalloc_node(x86_pmu.pebs_buffer_size, GFP_KERNEL, node);
+ buffer = dsalloc(x86_pmu.pebs_buffer_size, GFP_KERNEL, node);
if (unlikely(!buffer))
return -ENOMEM;
@@ -289,7 +326,7 @@ static int alloc_pebs_buffer(int cpu)
if (x86_pmu.intel_cap.pebs_format < 2) {
ibuffer = kzalloc_node(PEBS_FIXUP_SIZE, GFP_KERNEL, node);
if (!ibuffer) {
- kfree(buffer);
+ dsfree(buffer, x86_pmu.pebs_buffer_size);
return -ENOMEM;
}
per_cpu(insn_buffer, cpu) = ibuffer;
@@ -315,7 +352,8 @@ static void release_pebs_buffer(int cpu)
kfree(per_cpu(insn_buffer, cpu));
per_cpu(insn_buffer, cpu) = NULL;
- kfree((void *)(unsigned long)ds->pebs_buffer_base);
+ dsfree((void *)(unsigned long)ds->pebs_buffer_base,
+ x86_pmu.pebs_buffer_size);
ds->pebs_buffer_base = 0;
}
@@ -329,7 +367,7 @@ static int alloc_bts_buffer(int cpu)
if (!x86_pmu.bts)
return 0;
- buffer = kzalloc_node(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, node);
+ buffer = dsalloc(BTS_BUFFER_SIZE, GFP_KERNEL | __GFP_NOWARN, node);
if (unlikely(!buffer)) {
WARN_ONCE(1, "%s: BTS buffer allocation failure\n", __func__);
return -ENOMEM;
@@ -355,19 +393,15 @@ static void release_bts_buffer(int cpu)
if (!ds || !x86_pmu.bts)
return;
- kfree((void *)(unsigned long)ds->bts_buffer_base);
+ dsfree((void *)(unsigned long)ds->bts_buffer_base, BTS_BUFFER_SIZE);
ds->bts_buffer_base = 0;
}
static int alloc_ds_buffer(int cpu)
{
- int node = cpu_to_node(cpu);
- struct debug_store *ds;
-
- ds = kzalloc_node(sizeof(*ds), GFP_KERNEL, node);
- if (unlikely(!ds))
- return -ENOMEM;
+ struct debug_store *ds = per_cpu_ptr(&cpu_debug_store, cpu);
+ memset(ds, 0, sizeof(*ds));
per_cpu(cpu_hw_events, cpu).ds = ds;
return 0;
@@ -381,7 +415,6 @@ static void release_ds_buffer(int cpu)
return;
per_cpu(cpu_hw_events, cpu).ds = NULL;
- kfree(ds);
}
void release_ds_buffers(void)
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Yes, unmap_pud_range_nofree()'s declaration ought to be in a
header file really, but I'm not sure we want to use it anyway:
so for now just declare it inside kaiser_remove_mapping().
And there doesn't seem to be such a thing as unmap_p4d_range(),
even in a 5-level paging tree.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -285,8 +285,7 @@ void __init kaiser_init(void)
__PAGE_KERNEL);
}
-extern void unmap_pud_range_nofree(pgd_t *pgd, unsigned long start, unsigned long end);
-// add a mapping to the shadow-mapping, and synchronize the mappings
+/* Add a mapping to the shadow mapping, and synchronize the mappings */
int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
{
return kaiser_add_user_map((const void *)addr, size, flags);
@@ -294,15 +293,13 @@ int kaiser_add_mapping(unsigned long add
void kaiser_remove_mapping(unsigned long start, unsigned long size)
{
+ extern void unmap_pud_range_nofree(pgd_t *pgd,
+ unsigned long start, unsigned long end);
unsigned long end = start + size;
unsigned long addr;
for (addr = start; addr < end; addr += PGDIR_SIZE) {
pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(addr));
- /*
- * unmap_p4d_range() handles > P4D_SIZE unmaps,
- * so no need to trim 'end'.
- */
unmap_pud_range_nofree(pgd, addr, end);
}
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
While trying to get our gold link to work, four cleanups:
matched the gdt_page declaration to its definition;
in fiddling unsuccessfully with PERCPU_INPUT(), lined up backslashes;
lined up the backslashes according to convention in percpu-defs.h;
deleted the unused irq_stack_pointer addition to irq_stack_union.
Sad to report that aligning backslashes does not appear to help gold
align to 8192: but while these did not help, they are worth keeping.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/desc.h | 2 +-
arch/x86/include/asm/processor.h | 5 -----
include/asm-generic/vmlinux.lds.h | 18 ++++++++----------
include/linux/percpu-defs.h | 24 ++++++++++++------------
4 files changed, 21 insertions(+), 28 deletions(-)
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -43,7 +43,7 @@ struct gdt_page {
struct desc_struct gdt[GDT_ENTRIES];
} __attribute__((aligned(PAGE_SIZE)));
-DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);
+DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(struct gdt_page, gdt_page);
static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
{
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -335,11 +335,6 @@ union irq_stack_union {
char gs_base[40];
unsigned long stack_canary;
};
-
- struct {
- char irq_stack_pointer[64];
- char unused[IRQ_STACK_SIZE - 64];
- };
};
DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible;
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -778,16 +778,14 @@
*/
#define PERCPU_INPUT(cacheline) \
VMLINUX_SYMBOL(__per_cpu_start) = .; \
- \
- VMLINUX_SYMBOL(__per_cpu_user_mapped_start) = .; \
- *(.data..percpu..first) \
- . = ALIGN(cacheline); \
- *(.data..percpu..user_mapped) \
- *(.data..percpu..user_mapped..shared_aligned) \
- . = ALIGN(PAGE_SIZE); \
- *(.data..percpu..user_mapped..page_aligned) \
- VMLINUX_SYMBOL(__per_cpu_user_mapped_end) = .; \
- \
+ VMLINUX_SYMBOL(__per_cpu_user_mapped_start) = .; \
+ *(.data..percpu..first) \
+ . = ALIGN(cacheline); \
+ *(.data..percpu..user_mapped) \
+ *(.data..percpu..user_mapped..shared_aligned) \
+ . = ALIGN(PAGE_SIZE); \
+ *(.data..percpu..user_mapped..page_aligned) \
+ VMLINUX_SYMBOL(__per_cpu_user_mapped_end) = .; \
. = ALIGN(PAGE_SIZE); \
*(.data..percpu..page_aligned) \
. = ALIGN(cacheline); \
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -121,10 +121,10 @@
#define DEFINE_PER_CPU(type, name) \
DEFINE_PER_CPU_SECTION(type, name, "")
-#define DECLARE_PER_CPU_USER_MAPPED(type, name) \
+#define DECLARE_PER_CPU_USER_MAPPED(type, name) \
DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
-#define DEFINE_PER_CPU_USER_MAPPED(type, name) \
+#define DEFINE_PER_CPU_USER_MAPPED(type, name) \
DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
/*
@@ -156,11 +156,11 @@
DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
____cacheline_aligned_in_smp
-#define DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
+#define DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
____cacheline_aligned_in_smp
-#define DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
+#define DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
____cacheline_aligned_in_smp
@@ -185,18 +185,18 @@
/*
* Declaration/definition used for per-CPU variables that must be page aligned and need to be mapped in user mode.
*/
-#define DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
- DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
- __aligned(PAGE_SIZE)
-
-#define DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
- DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
- __aligned(PAGE_SIZE)
+#define DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
+ DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
+ __aligned(PAGE_SIZE)
+
+#define DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
+ DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
+ __aligned(PAGE_SIZE)
/*
* Declaration/definition used for per-CPU variables that must be read mostly.
*/
-#define DECLARE_PER_CPU_READ_MOSTLY(type, name) \
+#define DECLARE_PER_CPU_READ_MOSTLY(type, name) \
DECLARE_PER_CPU_SECTION(type, name, "..read_mostly")
#define DEFINE_PER_CPU_READ_MOSTLY(type, name) \
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Use tab not space so they line up properly, kaslr.o also.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/Makefile | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -37,5 +37,5 @@ obj-$(CONFIG_NUMA_EMU) += numa_emulatio
obj-$(CONFIG_X86_INTEL_MPX) += mpx.o
obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o
-obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
-obj-$(CONFIG_KAISER) += kaiser.o
+obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
+obj-$(CONFIG_KAISER) += kaiser.o
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
We fail to see what CONFIG_KAISER_REAL_SWITCH is for: it seems to be
left over from early development, and now just obscures tricky parts
of the code. Delete it before adding PCIDs, or nokaiser boot option.
(Or if there is some good reason to keep the option, then it needs
a help text - and a "depends on KAISER", so that all those without
KAISER are not asked the question. But we'd much rather delete it.)
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 4 ----
arch/x86/include/asm/kaiser.h | 4 ----
security/Kconfig | 4 ----
3 files changed, 12 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1317,9 +1317,7 @@ ENTRY(nmi)
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
pushq %rax
-#ifdef CONFIG_KAISER_REAL_SWITCH
andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
-#endif
movq %rax, %cr3
#endif
call do_nmi
@@ -1560,9 +1558,7 @@ end_repeat_nmi:
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
pushq %rax
-#ifdef CONFIG_KAISER_REAL_SWITCH
andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
-#endif
movq %rax, %cr3
#endif
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -21,17 +21,13 @@
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
-#ifdef CONFIG_KAISER_REAL_SWITCH
andq $(~KAISER_SHADOW_PGD_OFFSET), \reg
-#endif
movq \reg, %cr3
.endm
.macro _SWITCH_TO_USER_CR3 reg
movq %cr3, \reg
-#ifdef CONFIG_KAISER_REAL_SWITCH
orq $(KAISER_SHADOW_PGD_OFFSET), \reg
-#endif
movq \reg, %cr3
.endm
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -41,10 +41,6 @@ config KAISER
If you are unsure how to answer this question, answer Y.
-config KAISER_REAL_SWITCH
- bool "KAISER: actually switch page tables"
- default y
-
config SECURITYFS
bool "Enable the securityfs filesystem"
help
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Neel Natu points out that paranoid_entry() was wrong to assume that
an entry that did not need swapgs would not need SWITCH_KERNEL_CR3:
paranoid_entry (used for debug breakpoint, int3, double fault or MCE;
though I think it's only the MCE case that is cause for concern here)
can break in at an awkward time, between cr3 switch and swapgs, but
its handling always needs kernel gs and kernel cr3.
Easy to fix in itself, but paranoid_entry() also needs to convey to
paranoid_exit() (and my reading of macro idtentry says paranoid_entry
and paranoid_exit are always paired) how to restore the prior state.
The swapgs state is already conveyed by %ebx (0 or 1), so extend that
also to convey when SWITCH_USER_CR3 will be needed (2 or 3).
(Yes, I'd much prefer that 0 meant no swapgs, whereas it's the other
way round: and a convention shared with error_entry() and error_exit(),
which I don't want to touch. Perhaps I should have inverted the bit
for switch cr3 too, but did not.)
paranoid_exit() would be straightforward, except for TRACE_IRQS: it
did TRACE_IRQS_IRETQ when doing swapgs, but TRACE_IRQS_IRETQ_DEBUG
when not: which is it supposed to use when SWITCH_USER_CR3 is split
apart from that? As best as I can determine, commit 5963e317b1e9
("ftrace/x86: Do not change stacks in DEBUG when calling lockdep")
missed the swapgs case, and should have used TRACE_IRQS_IRETQ_DEBUG
there too (the discrepancy has nothing to do with the liberal use
of _NO_STACK and _UNSAFE_STACK hereabouts: TRACE_IRQS_OFF_DEBUG has
just been used in all cases); discrepancy lovingly preserved across
several paranoid_exit() cleanups, but I'm now removing it.
Neel further indicates that to use SWITCH_USER_CR3_NO_STACK there in
paranoid_exit() is now not only unnecessary but unsafe: might corrupt
syscall entry's unsafe_stack_register_backup of %rax. Just use
SWITCH_USER_CR3: and delete SWITCH_USER_CR3_NO_STACK altogether,
before we make the mistake of using it again.
hughd adds: this commit fixes an issue in the Kaiser-without-PCIDs
part of the series, and ought to be moved earlier, if you decided
to make a release of Kaiser-without-PCIDs.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 46 ++++++++++++++++++++++++++++++---------
arch/x86/entry/entry_64_compat.S | 2 -
arch/x86/include/asm/kaiser.h | 8 ------
3 files changed, 37 insertions(+), 19 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1053,7 +1053,11 @@ idtentry machine_check has_error_cod
/*
* Save all registers in pt_regs, and switch gs if needed.
* Use slow, but surefire "are we in kernel?" check.
- * Return: ebx=0: need swapgs on exit, ebx=1: otherwise
+ *
+ * Return: ebx=0: needs swapgs but not SWITCH_USER_CR3 in paranoid_exit
+ * ebx=1: needs neither swapgs nor SWITCH_USER_CR3 in paranoid_exit
+ * ebx=2: needs both swapgs and SWITCH_USER_CR3 in paranoid_exit
+ * ebx=3: needs SWITCH_USER_CR3 but not swapgs in paranoid_exit
*/
ENTRY(paranoid_entry)
cld
@@ -1065,9 +1069,26 @@ ENTRY(paranoid_entry)
testl %edx, %edx
js 1f /* negative -> in kernel */
SWAPGS
- SWITCH_KERNEL_CR3
xorl %ebx, %ebx
-1: ret
+1:
+#ifdef CONFIG_KAISER
+ /*
+ * We might have come in between a swapgs and a SWITCH_KERNEL_CR3
+ * on entry, or between a SWITCH_USER_CR3 and a swapgs on exit.
+ * Do a conditional SWITCH_KERNEL_CR3: this could safely be done
+ * unconditionally, but we need to find out whether the reverse
+ * should be done on return (conveyed to paranoid_exit in %ebx).
+ */
+ movq %cr3, %rax
+ testl $KAISER_SHADOW_PGD_OFFSET, %eax
+ jz 2f
+ orl $2, %ebx
+ andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
+ orq x86_cr3_pcid_noflush, %rax
+ movq %rax, %cr3
+2:
+#endif
+ ret
END(paranoid_entry)
/*
@@ -1080,20 +1101,25 @@ END(paranoid_entry)
* be complicated. Fortunately, we there's no good reason
* to try to handle preemption here.
*
- * On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it)
+ * On entry: ebx=0: needs swapgs but not SWITCH_USER_CR3
+ * ebx=1: needs neither swapgs nor SWITCH_USER_CR3
+ * ebx=2: needs both swapgs and SWITCH_USER_CR3
+ * ebx=3: needs SWITCH_USER_CR3 but not swapgs
*/
ENTRY(paranoid_exit)
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF_DEBUG
- testl %ebx, %ebx /* swapgs needed? */
+ TRACE_IRQS_IRETQ_DEBUG
+#ifdef CONFIG_KAISER
+ testl $2, %ebx /* SWITCH_USER_CR3 needed? */
+ jz paranoid_exit_no_switch
+ SWITCH_USER_CR3
+paranoid_exit_no_switch:
+#endif
+ testl $1, %ebx /* swapgs needed? */
jnz paranoid_exit_no_swapgs
- TRACE_IRQS_IRETQ
- SWITCH_USER_CR3_NO_STACK
SWAPGS_UNSAFE_STACK
- jmp paranoid_exit_restore
paranoid_exit_no_swapgs:
- TRACE_IRQS_IRETQ_DEBUG
-paranoid_exit_restore:
RESTORE_EXTRA_REGS
RESTORE_C_REGS
REMOVE_PT_GPREGS_FROM_STACK 8
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -343,7 +343,7 @@ ENTRY(entry_INT80_compat)
/* Go back to user mode. */
TRACE_IRQS_ON
- SWITCH_USER_CR3_NO_STACK
+ SWITCH_USER_CR3
SWAPGS
jmp restore_regs_and_iret
END(entry_INT80_compat)
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -63,20 +63,12 @@ _SWITCH_TO_KERNEL_CR3 %rax
movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
.endm
-.macro SWITCH_USER_CR3_NO_STACK
-movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
-_SWITCH_TO_USER_CR3 %rax %al
-movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
-.endm
-
#else /* CONFIG_KAISER */
.macro SWITCH_KERNEL_CR3 reg
.endm
.macro SWITCH_USER_CR3 reg regb
.endm
-.macro SWITCH_USER_CR3_NO_STACK
-.endm
.macro SWITCH_KERNEL_CR3_NO_STACK
.endm
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
When removing the bogus comment from kaiser_remove_mapping(),
I really ought to have checked the extent of its bogosity: as
Neel points out, there is nothing to stop unmap_pud_range_nofree()
from continuing beyond the end of a pud (and starting in the wrong
position on the next).
Fix kaiser_remove_mapping() to constrain the extent and advance pgd
pointer correctly: use pgd_addr_end() macro as used throughout base
mm (but don't assume page-rounded start and size in this case).
But this bug was very unlikely to trigger in this backport: since
any buddy allocation is contained within a single pud extent, and
we are not using vmapped stacks (and are only mapping one page of
stack anyway): the only way to hit this bug here would be when
freeing a large modified ldt.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -319,11 +319,13 @@ void kaiser_remove_mapping(unsigned long
extern void unmap_pud_range_nofree(pgd_t *pgd,
unsigned long start, unsigned long end);
unsigned long end = start + size;
- unsigned long addr;
+ unsigned long addr, next;
+ pgd_t *pgd;
- for (addr = start; addr < end; addr += PGDIR_SIZE) {
- pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(addr));
- unmap_pud_range_nofree(pgd, addr, end);
+ pgd = native_get_shadow_pgd(pgd_offset_k(start));
+ for (addr = start; addr < end; pgd++, addr = next) {
+ next = pgd_addr_end(addr, end);
+ unmap_pud_range_nofree(pgd, addr, next);
}
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <[email protected]>
Concentrate it in arch/x86/mm/kaiser.c and use the upstream string "nopti".
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/kernel-parameters.txt | 2 +-
arch/x86/kernel/cpu/common.c | 18 ------------------
arch/x86/mm/kaiser.c | 20 +++++++++++++++++++-
3 files changed, 20 insertions(+), 20 deletions(-)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2763,7 +2763,7 @@ bytes respectively. Such letter suffixes
nojitter [IA-64] Disables jitter checking for ITC timers.
- nokaiser [X86-64] Disable KAISER isolation of kernel from user.
+ nopti [X86-64] Disable KAISER isolation of kernel from user.
no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -179,20 +179,6 @@ static int __init x86_pcid_setup(char *s
return 1;
}
__setup("nopcid", x86_pcid_setup);
-
-static int __init x86_nokaiser_setup(char *s)
-{
- /* nokaiser doesn't accept parameters */
- if (s)
- return -EINVAL;
-#ifdef CONFIG_KAISER
- kaiser_enabled = 0;
- setup_clear_cpu_cap(X86_FEATURE_KAISER);
- pr_info("nokaiser: KAISER feature disabled\n");
-#endif
- return 0;
-}
-early_param("nokaiser", x86_nokaiser_setup);
#endif
static int __init x86_noinvpcid_setup(char *s)
@@ -813,10 +799,6 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
init_scattered_cpuid_features(c);
-#ifdef CONFIG_KAISER
- if (kaiser_enabled)
- set_cpu_cap(c, X86_FEATURE_KAISER);
-#endif
}
static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -274,8 +274,13 @@ void __init kaiser_init(void)
{
int cpu;
- if (!kaiser_enabled)
+ if (!kaiser_enabled) {
+ setup_clear_cpu_cap(X86_FEATURE_KAISER);
return;
+ }
+
+ setup_force_cpu_cap(X86_FEATURE_KAISER);
+
kaiser_init_all_pgds();
for_each_possible_cpu(cpu) {
@@ -418,3 +423,16 @@ void kaiser_flush_tlb_on_return_to_user(
X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
}
EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
+
+static int __init x86_nokaiser_setup(char *s)
+{
+ /* nopti doesn't accept parameters */
+ if (s)
+ return -EINVAL;
+
+ kaiser_enabled = 0;
+ pr_info("Kernel/User page tables isolation: disabled\n");
+
+ return 0;
+}
+early_param("nopti", x86_nokaiser_setup);
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Now that we're playing the ALTERNATIVE game, use that more efficient
method: instead of user-mapping an extra page, and reading an extra
cacheline each time for x86_cr3_pcid_noflush.
Neel has found that __stringify(bts $X86_CR3_PCID_NOFLUSH_BIT, %rax)
is a working substitute for the "bts $63, %rax" in these ALTERNATIVEs;
but the one line with $63 in looks clearer, so let's stick with that.
Worried about what happens with an ALTERNATIVE between the jump and
jump label in another ALTERNATIVE? I was, but have checked the
combinations in SWITCH_KERNEL_CR3_NO_STACK at entry_SYSCALL_64,
and it does a good job.
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 7 ++++---
arch/x86/include/asm/kaiser.h | 6 +++---
arch/x86/mm/kaiser.c | 11 +----------
3 files changed, 8 insertions(+), 16 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1084,7 +1084,8 @@ ENTRY(paranoid_entry)
jz 2f
orl $2, %ebx
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
- orq x86_cr3_pcid_noflush, %rax
+ /* If PCID enabled, set X86_CR3_PCID_NOFLUSH_BIT */
+ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID
movq %rax, %cr3
2:
#endif
@@ -1344,7 +1345,7 @@ ENTRY(nmi)
/* %rax is saved above, so OK to clobber here */
ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
/* If PCID enabled, NOFLUSH now and NOFLUSH on return */
- orq x86_cr3_pcid_noflush, %rax
+ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
@@ -1588,7 +1589,7 @@ end_repeat_nmi:
/* %rax is saved above, so OK to clobber here */
ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
/* If PCID enabled, NOFLUSH now and NOFLUSH on return */
- orq x86_cr3_pcid_noflush, %rax
+ ALTERNATIVE "", "bts $63, %rax", X86_FEATURE_PCID
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -25,7 +25,8 @@
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
-orq x86_cr3_pcid_noflush, \reg
+/* If PCID enabled, set X86_CR3_PCID_NOFLUSH_BIT */
+ALTERNATIVE "", "bts $63, \reg", X86_FEATURE_PCID
movq \reg, %cr3
.endm
@@ -39,7 +40,7 @@ movq \reg, %cr3
movq %cr3, \reg
orq PER_CPU_VAR(x86_cr3_pcid_user), \reg
js 9f
-/* FLUSH this time, reset to NOFLUSH for next time (if PCID enabled) */
+/* If PCID enabled, FLUSH this time, reset to NOFLUSH for next time */
movb \regb, PER_CPU_VAR(x86_cr3_pcid_user+7)
9:
movq \reg, %cr3
@@ -90,7 +91,6 @@ movq PER_CPU_VAR(unsafe_stack_register_b
*/
DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
-extern unsigned long x86_cr3_pcid_noflush;
DECLARE_PER_CPU(unsigned long, x86_cr3_pcid_user);
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -31,7 +31,6 @@ DEFINE_PER_CPU_USER_MAPPED(unsigned long
* This is also handy because systems that do not support PCIDs
* just end up or'ing a 0 into their CR3, which does no harm.
*/
-unsigned long x86_cr3_pcid_noflush __read_mostly;
DEFINE_PER_CPU(unsigned long, x86_cr3_pcid_user);
/*
@@ -356,10 +355,6 @@ void __init kaiser_init(void)
kaiser_add_user_map_early(&debug_idt_table,
sizeof(gate_desc) * NR_VECTORS,
__PAGE_KERNEL);
-
- kaiser_add_user_map_early(&x86_cr3_pcid_noflush,
- sizeof(x86_cr3_pcid_noflush),
- __PAGE_KERNEL);
}
/* Add a mapping to the shadow mapping, and synchronize the mappings */
@@ -433,18 +428,14 @@ pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp,
void kaiser_setup_pcid(void)
{
- unsigned long kern_cr3 = 0;
unsigned long user_cr3 = KAISER_SHADOW_PGD_OFFSET;
- if (this_cpu_has(X86_FEATURE_PCID)) {
- kern_cr3 |= X86_CR3_PCID_KERN_NOFLUSH;
+ if (this_cpu_has(X86_FEATURE_PCID))
user_cr3 |= X86_CR3_PCID_USER_NOFLUSH;
- }
/*
* These variables are used by the entry/exit
* code to change PCID and pgd and TLB flushing.
*/
- x86_cr3_pcid_noflush = kern_cr3;
this_cpu_write(x86_cr3_pcid_user, user_cr3);
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
I found asm/tlbflush.h too twisty, and think it safer not to avoid
__native_flush_tlb_global_irq_disabled() in the kaiser_enabled case,
but instead let it handle kaiser_enabled along with cr3: it can just
use __native_flush_tlb() for that, no harm in re-disabling preemption.
(This is not the same change as Kirill and Dave have suggested for
upstream, flipping PGE in cr4: that's neat, but needs a cpu_has_pge
check; cr3 is enough for kaiser, and thought to be cheaper than cr4.)
Also delete the X86_FEATURE_INVPCID invpcid_flush_all_nonglobals()
preference from __native_flush_tlb(): unlike the invpcid_flush_all()
preference in __native_flush_tlb_global(), it's not seen in upstream
4.14, and was recently reported to be surprisingly slow.
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/tlbflush.h | 27 +++------------------------
1 file changed, 3 insertions(+), 24 deletions(-)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -152,14 +152,6 @@ static inline void kaiser_flush_tlb_on_r
static inline void __native_flush_tlb(void)
{
- if (this_cpu_has(X86_FEATURE_INVPCID)) {
- /*
- * Note, this works with CR4.PCIDE=0 or 1.
- */
- invpcid_flush_all_nonglobals();
- return;
- }
-
/*
* If current->mm == NULL then we borrow a mm which may change during a
* task switch and therefore we must not be preempted while we write CR3
@@ -183,11 +175,8 @@ static inline void __native_flush_tlb_gl
/* restore PGE as it was before */
native_write_cr4(cr4);
} else {
- /*
- * x86_64 microcode update comes this way when CR4.PGE is not
- * enabled, and it's safer for all callers to allow this case.
- */
- native_write_cr3(native_read_cr3());
+ /* do it with cr3, letting kaiser flush user PCID */
+ __native_flush_tlb();
}
}
@@ -195,12 +184,6 @@ static inline void __native_flush_tlb_gl
{
unsigned long flags;
- if (kaiser_enabled) {
- /* Globals are not used at all */
- __native_flush_tlb();
- return;
- }
-
if (this_cpu_has(X86_FEATURE_INVPCID)) {
/*
* Using INVPCID is considerably faster than a pair of writes
@@ -256,11 +239,7 @@ static inline void __native_flush_tlb_si
static inline void __flush_tlb_all(void)
{
- if (boot_cpu_has(X86_FEATURE_PGE))
- __flush_tlb_global();
- else
- __flush_tlb();
-
+ __flush_tlb_global();
/*
* Note: if we somehow had PCID but not PGE, then this wouldn't work --
* we'd end up flushing kernel translations for the current ASID but
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
I have not observed a might_sleep() warning from setup_fixmap_gdt()'s
use of kaiser_add_mapping() in our tree (why not?), but like upstream
we have not provided a way for that to pass is_atomic true down to
kaiser_pagetable_walk(), and at startup it's far from a likely source
of trouble: so just delete the walk's is_atomic arg and might_sleep().
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -107,19 +107,13 @@ static inline unsigned long get_pa_from_
*
* Returns a pointer to a PTE on success, or NULL on failure.
*/
-static pte_t *kaiser_pagetable_walk(unsigned long address, bool is_atomic)
+static pte_t *kaiser_pagetable_walk(unsigned long address)
{
pmd_t *pmd;
pud_t *pud;
pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(address));
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- if (is_atomic) {
- gfp &= ~GFP_KERNEL;
- gfp |= __GFP_HIGH | __GFP_ATOMIC;
- } else
- might_sleep();
-
if (pgd_none(*pgd)) {
WARN_ONCE(1, "All shadow pgds should have been populated");
return NULL;
@@ -194,7 +188,7 @@ static int kaiser_add_user_map(const voi
ret = -EIO;
break;
}
- pte = kaiser_pagetable_walk(address, false);
+ pte = kaiser_pagetable_walk(address);
if (!pte) {
ret = -ENOMEM;
break;
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
native_pgd_clear() uses native_set_pgd(), so native_set_pgd() must
avoid setting the _PAGE_NX bit on an otherwise pgd_none() entry:
usually that just generated a warning on exit, but sometimes
more mysterious and damaging failures (our production machines
could not complete booting).
The original fix to this just avoided adding _PAGE_NX to
an empty entry; but eventually more problems surfaced with kexec,
and EFI mapping expected to be a problem too. So now instead
change native_set_pgd() to update shadow only if _PAGE_USER:
A few places (kernel/machine_kexec_64.c, platform/efi/efi_64.c for sure)
use set_pgd() to set up a temporary internal virtual address space, with
physical pages remapped at what Kaiser regards as userspace addresses:
Kaiser then assumes a shadow pgd follows, which it will try to corrupt.
This appears to be responsible for the recent kexec and kdump failures;
though it's unclear how those did not manifest as a problem before.
Ah, the shadow pgd will only be assumed to "follow" if the requested
pgd is on an even-numbered page: so I suppose it was going wrong 50%
of the time all along.
What we need is a flag to set_pgd(), to tell it we're dealing with
userspace. Er, isn't that what the pgd's _PAGE_USER bit is saying?
Add a test for that. But we cannot do the same for pgd_clear()
(which may be called to clear corrupted entries - set aside the
question of "corrupt in which pgd?" until later), so there just
rely on pgd_clear() not being called in the problematic cases -
with a WARN_ON_ONCE() which should fire half the time if it is.
But this is getting too big for an inline function: move it into
arch/x86/mm/kaiser.c (which then demands a boot/compressed mod);
and de-void and de-space native_get_shadow/normal_pgd() while here.
Also make an unnecessary change to KASLR's init_trampoline(): it was
using set_pgd() to assign a pgd-value to a global variable (not in a
pg directory page), which was rather scary given Kaiser's previous
set_pgd() implementation: not a problem now, but too scary to leave
as was, it could easily blow up if we have to change set_pgd() again.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/boot/compressed/misc.h | 1
arch/x86/include/asm/pgtable_64.h | 51 +++++++++-----------------------------
arch/x86/mm/kaiser.c | 42 +++++++++++++++++++++++++++++++
arch/x86/mm/kaslr.c | 4 +-
4 files changed, 58 insertions(+), 40 deletions(-)
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -9,6 +9,7 @@
*/
#undef CONFIG_PARAVIRT
#undef CONFIG_PARAVIRT_SPINLOCKS
+#undef CONFIG_KAISER
#undef CONFIG_KASAN
#include <linux/linkage.h>
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -107,61 +107,36 @@ static inline void native_pud_clear(pud_
}
#ifdef CONFIG_KAISER
-static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp)
+extern pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd);
+
+static inline pgd_t *native_get_shadow_pgd(pgd_t *pgdp)
{
- return (pgd_t *)(void*)((unsigned long)(void*)pgdp | (unsigned long)PAGE_SIZE);
+ return (pgd_t *)((unsigned long)pgdp | (unsigned long)PAGE_SIZE);
}
-static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp)
+static inline pgd_t *native_get_normal_pgd(pgd_t *pgdp)
{
- return (pgd_t *)(void*)((unsigned long)(void*)pgdp & ~(unsigned long)PAGE_SIZE);
+ return (pgd_t *)((unsigned long)pgdp & ~(unsigned long)PAGE_SIZE);
}
#else
-static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp)
+static inline pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd)
+{
+ return pgd;
+}
+static inline pgd_t *native_get_shadow_pgd(pgd_t *pgdp)
{
BUILD_BUG_ON(1);
return NULL;
}
-static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp)
+static inline pgd_t *native_get_normal_pgd(pgd_t *pgdp)
{
return pgdp;
}
#endif /* CONFIG_KAISER */
-/*
- * Page table pages are page-aligned. The lower half of the top
- * level is used for userspace and the top half for the kernel.
- * This returns true for user pages that need to get copied into
- * both the user and kernel copies of the page tables, and false
- * for kernel pages that should only be in the kernel copy.
- */
-static inline bool is_userspace_pgd(void *__ptr)
-{
- unsigned long ptr = (unsigned long)__ptr;
-
- return ((ptr % PAGE_SIZE) < (PAGE_SIZE / 2));
-}
-
static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
{
-#ifdef CONFIG_KAISER
- pteval_t extra_kern_pgd_flags = 0;
- /* Do we need to also populate the shadow pgd? */
- if (is_userspace_pgd(pgdp)) {
- native_get_shadow_pgd(pgdp)->pgd = pgd.pgd;
- /*
- * Even if the entry is *mapping* userspace, ensure
- * that userspace can not use it. This way, if we
- * get out to userspace running on the kernel CR3,
- * userspace will crash instead of running.
- */
- extra_kern_pgd_flags = _PAGE_NX;
- }
- pgdp->pgd = pgd.pgd;
- pgdp->pgd |= extra_kern_pgd_flags;
-#else /* CONFIG_KAISER */
- *pgdp = pgd;
-#endif
+ *pgdp = kaiser_set_shadow_pgd(pgdp, pgd);
}
static inline void native_pgd_clear(pgd_t *pgd)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -302,4 +302,46 @@ void kaiser_remove_mapping(unsigned long
unmap_pud_range_nofree(pgd, addr, end);
}
}
+
+/*
+ * Page table pages are page-aligned. The lower half of the top
+ * level is used for userspace and the top half for the kernel.
+ * This returns true for user pages that need to get copied into
+ * both the user and kernel copies of the page tables, and false
+ * for kernel pages that should only be in the kernel copy.
+ */
+static inline bool is_userspace_pgd(pgd_t *pgdp)
+{
+ return ((unsigned long)pgdp % PAGE_SIZE) < (PAGE_SIZE / 2);
+}
+
+pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd)
+{
+ /*
+ * Do we need to also populate the shadow pgd? Check _PAGE_USER to
+ * skip cases like kexec and EFI which make temporary low mappings.
+ */
+ if (pgd.pgd & _PAGE_USER) {
+ if (is_userspace_pgd(pgdp)) {
+ native_get_shadow_pgd(pgdp)->pgd = pgd.pgd;
+ /*
+ * Even if the entry is *mapping* userspace, ensure
+ * that userspace can not use it. This way, if we
+ * get out to userspace running on the kernel CR3,
+ * userspace will crash instead of running.
+ */
+ pgd.pgd |= _PAGE_NX;
+ }
+ } else if (!pgd.pgd) {
+ /*
+ * pgd_clear() cannot check _PAGE_USER, and is even used to
+ * clear corrupted pgd entries: so just rely on cases like
+ * kexec and EFI never to be using pgd_clear().
+ */
+ if (!WARN_ON_ONCE((unsigned long)pgdp & PAGE_SIZE) &&
+ is_userspace_pgd(pgdp))
+ native_get_shadow_pgd(pgdp)->pgd = pgd.pgd;
+ }
+ return pgd;
+}
#endif /* CONFIG_KAISER */
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -189,6 +189,6 @@ void __meminit init_trampoline(void)
*pud_tramp = *pud;
}
- set_pgd(&trampoline_pgd_entry,
- __pgd(_KERNPG_TABLE | __pa(pud_page_tramp)));
+ /* Avoid set_pgd(), in case it's complicated by CONFIG_KAISER */
+ trampoline_pgd_entry = __pgd(_KERNPG_TABLE | __pa(pud_page_tramp));
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Include linux/kaiser.h instead of asm/kaiser.h to build ldt.c without
CONFIG_KAISER. kaiser_add_mapping() does already return an error code,
so fix the FIXME.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/ldt.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -16,9 +16,9 @@
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
+#include <linux/kaiser.h>
#include <asm/ldt.h>
-#include <asm/kaiser.h>
#include <asm/desc.h>
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
@@ -49,7 +49,7 @@ static struct ldt_struct *alloc_ldt_stru
{
struct ldt_struct *new_ldt;
int alloc_size;
- int ret = 0;
+ int ret;
if (size > LDT_ENTRIES)
return NULL;
@@ -77,10 +77,8 @@ static struct ldt_struct *alloc_ldt_stru
return NULL;
}
- // FIXME: make kaiser_add_mapping() return an error code
- // when it fails
- kaiser_add_mapping((unsigned long)new_ldt->entries, alloc_size,
- __PAGE_KERNEL);
+ ret = kaiser_add_mapping((unsigned long)new_ldt->entries, alloc_size,
+ __PAGE_KERNEL);
if (ret) {
__free_ldt_struct(new_ldt);
return NULL;
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
It is absurd that KAISER should depend on SMP, but apparently nobody
has tried a UP build before: which breaks on implicit declaration of
function 'per_cpu_offset' in arch/x86/mm/kaiser.c.
Now, you would expect that to be trivially fixed up; but looking at
the System.map when that block is #ifdef'ed out of kaiser_init(),
I see that in a UP build __per_cpu_user_mapped_end is precisely at
__per_cpu_user_mapped_start, and the items carefully gathered into
that section for user-mapping on SMP, dispersed elsewhere on UP.
So, some other kind of section assignment will be needed on UP,
but implementing that is not a priority: just make KAISER depend
on SMP for now.
Also inserted a blank line before the option, tidied up the
brief Kconfig help message, and added an "If unsure, Y".
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
security/Kconfig | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -30,14 +30,16 @@ config SECURITY
model will be used.
If you are unsure how to answer this question, answer N.
+
config KAISER
bool "Remove the kernel mapping in user mode"
default y
- depends on X86_64
- depends on !PARAVIRT
+ depends on X86_64 && SMP && !PARAVIRT
help
- This enforces a strict kernel and user space isolation in order to close
- hardware side channels on kernel address information.
+ This enforces a strict kernel and user space isolation, in order
+ to close hardware side channels on kernel address information.
+
+ If you are unsure how to answer this question, answer Y.
config KAISER_REAL_SWITCH
bool "KAISER: actually switch page tables"
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
pjt has observed that nmi's second (nmi_from_kernel) call to do_nmi()
adjusted the %rdi regs arg, rightly when CONFIG_KAISER, but wrongly
when not CONFIG_KAISER.
Although the minimal change is to add an #ifdef CONFIG_KAISER around
the addq line, that looks cluttered, and I prefer how the first call
to do_nmi() handled it: prepare args in %rdi and %rsi before getting
into the CONFIG_KAISER block, since it does not touch them at all.
And while we're here, place the "#ifdef CONFIG_KAISER" that follows
each, to enclose the "Unconditionally restore CR3" comment: matching
how the "Unconditionally use kernel CR3" comment above is enclosed.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1323,12 +1323,13 @@ ENTRY(nmi)
movq %rax, %cr3
#endif
call do_nmi
+
+#ifdef CONFIG_KAISER
/*
* Unconditionally restore CR3. I know we return to
* kernel code that needs user CR3, but do we ever return
* to "user mode" where we need the kernel CR3?
*/
-#ifdef CONFIG_KAISER
popq %rax
mov %rax, %cr3
#endif
@@ -1552,6 +1553,8 @@ end_repeat_nmi:
SWAPGS
xorl %ebx, %ebx
1:
+ movq %rsp, %rdi
+ movq $-1, %rsi
#ifdef CONFIG_KAISER
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
@@ -1564,16 +1567,14 @@ end_repeat_nmi:
#endif
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
- movq %rsp, %rdi
- addq $8, %rdi /* point %rdi at ptregs, fixed up for CR3 */
- movq $-1, %rsi
call do_nmi
+
+#ifdef CONFIG_KAISER
/*
* Unconditionally restore CR3. We might be returning to
* kernel code that needs user CR3, like just just before
* a sysret.
*/
-#ifdef CONFIG_KAISER
popq %rax
mov %rax, %cr3
#endif
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Neal Cardwell <[email protected]>
commit 2f6c498e4f15d27852c04ed46d804a39137ba364 upstream.
Fix BBR so that upon notification of a loss recovery undo BBR resets
the full pipe detection (STARTUP exit) state machine.
Under high reordering, reordering events can be interpreted as loss.
If the reordering and spurious loss estimates are high enough, this
could previously cause BBR to spuriously estimate that the pipe is
full.
Since spurious loss recovery means that our overall sending will have
slowed down spuriously, this commit gives a flow more time to probe
robustly for bandwidth and decide the pipe is really full.
Signed-off-by: Neal Cardwell <[email protected]>
Reviewed-by: Yuchung Cheng <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/ipv4/tcp_bbr.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -843,6 +843,10 @@ static u32 bbr_sndbuf_expand(struct sock
*/
static u32 bbr_undo_cwnd(struct sock *sk)
{
+ struct bbr *bbr = inet_csk_ca(sk);
+
+ bbr->full_bw = 0; /* spurious slow-down; reset full pipe detection */
+ bbr->full_bw_cnt = 0;
return tcp_sk(sk)->snd_cwnd;
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <[email protected]>
Now that the required bits have been addressed, reenable
PARAVIRT.
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
security/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -34,7 +34,7 @@ config SECURITY
config KAISER
bool "Remove the kernel mapping in user mode"
default y
- depends on X86_64 && SMP && !PARAVIRT
+ depends on X86_64 && SMP
help
This enforces a strict kernel and user space isolation, in order
to close hardware side channels on kernel address information.
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kees Cook <[email protected]>
Make sure dmesg reports when KPTI is enabled.
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -10,6 +10,9 @@
#include <linux/mm.h>
#include <linux/uaccess.h>
+#undef pr_fmt
+#define pr_fmt(fmt) "Kernel/User page tables isolation: " fmt
+
#include <asm/kaiser.h>
#include <asm/tlbflush.h> /* to verify its kaiser declarations */
#include <asm/pgtable.h>
@@ -292,7 +295,7 @@ enable:
return;
disable:
- pr_info("Kernel/User page tables isolation: disabled\n");
+ pr_info("disabled\n");
silent_disable:
kaiser_enabled = 0;
@@ -352,6 +355,8 @@ void __init kaiser_init(void)
kaiser_add_user_map_early(&debug_idt_table,
sizeof(gate_desc) * NR_VECTORS,
__PAGE_KERNEL);
+
+ pr_info("enabled\n");
}
/* Add a mapping to the shadow mapping, and synchronize the mappings */
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Let kaiser_flush_tlb_on_return_to_user() do the X86_FEATURE_PCID
check, instead of each caller doing it inline first: nobody needs
to optimize for the noPCID case, it's clearer this way, and better
suits later changes. Replace those no-op X86_CR3_PCID_KERN_FLUSH lines
by a BUILD_BUG_ON() in load_new_mm_cr3(), in case something changes.
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/tlbflush.h | 4 ++--
arch/x86/mm/kaiser.c | 6 +++---
arch/x86/mm/tlb.c | 8 ++++----
3 files changed, 9 insertions(+), 9 deletions(-)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -158,7 +158,7 @@ static inline void __native_flush_tlb(vo
* back:
*/
preempt_disable();
- if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID))
+ if (kaiser_enabled)
kaiser_flush_tlb_on_return_to_user();
native_write_cr3(native_read_cr3());
preempt_enable();
@@ -217,7 +217,7 @@ static inline void __native_flush_tlb_si
*/
if (!this_cpu_has(X86_FEATURE_INVPCID_SINGLE)) {
- if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID))
+ if (kaiser_enabled)
kaiser_flush_tlb_on_return_to_user();
asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
return;
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -435,12 +435,12 @@ void kaiser_setup_pcid(void)
/*
* Make a note that this cpu will need to flush USER tlb on return to user.
- * Caller checks whether this_cpu_has(X86_FEATURE_PCID) before calling:
- * if cpu does not, then the NOFLUSH bit will never have been set.
+ * If cpu does not have PCID, then the NOFLUSH bit will never have been set.
*/
void kaiser_flush_tlb_on_return_to_user(void)
{
- this_cpu_write(x86_cr3_pcid_user,
+ if (this_cpu_has(X86_FEATURE_PCID))
+ this_cpu_write(x86_cr3_pcid_user,
X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
}
EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -39,7 +39,7 @@ static void load_new_mm_cr3(pgd_t *pgdir
{
unsigned long new_mm_cr3 = __pa(pgdir);
- if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID)) {
+ if (kaiser_enabled) {
/*
* We reuse the same PCID for different tasks, so we must
* flush all the entries for the PCID out when we change tasks.
@@ -50,10 +50,10 @@ static void load_new_mm_cr3(pgd_t *pgdir
* do it here, but can only be used if X86_FEATURE_INVPCID is
* available - and many machines support pcid without invpcid.
*
- * The line below is a no-op: X86_CR3_PCID_KERN_FLUSH is now 0;
- * but keep that line in there in case something changes.
+ * If X86_CR3_PCID_KERN_FLUSH actually added something, then it
+ * would be needed in the write_cr3() below - if PCIDs enabled.
*/
- new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH;
+ BUILD_BUG_ON(X86_CR3_PCID_KERN_FLUSH);
kaiser_flush_tlb_on_return_to_user();
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kees Cook <[email protected]>
This renames CONFIG_KAISER to CONFIG_PAGE_TABLE_ISOLATION.
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/boot/compressed/misc.h | 2 +-
arch/x86/entry/entry_64.S | 12 ++++++------
arch/x86/events/intel/ds.c | 4 ++--
arch/x86/include/asm/cpufeatures.h | 2 +-
arch/x86/include/asm/kaiser.h | 12 ++++++------
arch/x86/include/asm/pgtable.h | 4 ++--
arch/x86/include/asm/pgtable_64.h | 4 ++--
arch/x86/include/asm/pgtable_types.h | 2 +-
arch/x86/include/asm/tlbflush.h | 2 +-
arch/x86/kernel/head_64.S | 2 +-
arch/x86/mm/Makefile | 2 +-
arch/x86/mm/kaslr.c | 2 +-
include/linux/kaiser.h | 6 +++---
include/linux/percpu-defs.h | 2 +-
security/Kconfig | 2 +-
tools/arch/x86/include/asm/cpufeatures.h | 2 +-
16 files changed, 31 insertions(+), 31 deletions(-)
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -9,7 +9,7 @@
*/
#undef CONFIG_PARAVIRT
#undef CONFIG_PARAVIRT_SPINLOCKS
-#undef CONFIG_KAISER
+#undef CONFIG_PAGE_TABLE_ISOLATION
#undef CONFIG_KASAN
#include <linux/linkage.h>
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1071,7 +1071,7 @@ ENTRY(paranoid_entry)
SWAPGS
xorl %ebx, %ebx
1:
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* We might have come in between a swapgs and a SWITCH_KERNEL_CR3
* on entry, or between a SWITCH_USER_CR3 and a swapgs on exit.
@@ -1111,7 +1111,7 @@ ENTRY(paranoid_exit)
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF_DEBUG
TRACE_IRQS_IRETQ_DEBUG
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/* No ALTERNATIVE for X86_FEATURE_KAISER: paranoid_entry sets %ebx */
testl $2, %ebx /* SWITCH_USER_CR3 needed? */
jz paranoid_exit_no_switch
@@ -1340,7 +1340,7 @@ ENTRY(nmi)
movq %rsp, %rdi
movq $-1, %rsi
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
@@ -1354,7 +1354,7 @@ ENTRY(nmi)
#endif
call do_nmi
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* Unconditionally restore CR3. I know we return to
* kernel code that needs user CR3, but do we ever return
@@ -1584,7 +1584,7 @@ end_repeat_nmi:
1:
movq %rsp, %rdi
movq $-1, %rsi
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
@@ -1600,7 +1600,7 @@ end_repeat_nmi:
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
call do_nmi
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* Unconditionally restore CR3. We might be returning to
* kernel code that needs user CR3, like just just before
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -274,7 +274,7 @@ static DEFINE_PER_CPU(void *, insn_buffe
static void *dsalloc(size_t size, gfp_t flags, int node)
{
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
unsigned int order = get_order(size);
struct page *page;
unsigned long addr;
@@ -295,7 +295,7 @@ static void *dsalloc(size_t size, gfp_t
static void dsfree(const void *buffer, size_t size)
{
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
if (!buffer)
return;
kaiser_remove_mapping((unsigned long)buffer, size);
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -199,7 +199,7 @@
#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
-#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_KAISER w/o nokaiser */
+#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -20,7 +20,7 @@
#define KAISER_SHADOW_PGD_OFFSET 0x1000
#ifdef __ASSEMBLY__
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
@@ -69,7 +69,7 @@ movq PER_CPU_VAR(unsafe_stack_register_b
8:
.endm
-#else /* CONFIG_KAISER */
+#else /* CONFIG_PAGE_TABLE_ISOLATION */
.macro SWITCH_KERNEL_CR3
.endm
@@ -78,11 +78,11 @@ movq PER_CPU_VAR(unsafe_stack_register_b
.macro SWITCH_KERNEL_CR3_NO_STACK
.endm
-#endif /* CONFIG_KAISER */
+#endif /* CONFIG_PAGE_TABLE_ISOLATION */
#else /* __ASSEMBLY__ */
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* Upon kernel/user mode switch, it may happen that the address
* space has to be switched before the registers have been
@@ -100,10 +100,10 @@ extern void __init kaiser_check_boottime
#else
#define kaiser_enabled 0
static inline void __init kaiser_check_boottime_disable(void) {}
-#endif /* CONFIG_KAISER */
+#endif /* CONFIG_PAGE_TABLE_ISOLATION */
/*
- * Kaiser function prototypes are needed even when CONFIG_KAISER is not set,
+ * Kaiser function prototypes are needed even when CONFIG_PAGE_TABLE_ISOLATION is not set,
* so as to build with tests on kaiser_enabled instead of #ifdefs.
*/
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -18,7 +18,7 @@
#ifndef __ASSEMBLY__
#include <asm/x86_init.h>
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
extern int kaiser_enabled;
#else
#define kaiser_enabled 0
@@ -920,7 +920,7 @@ static inline void pmdp_set_wrprotect(st
static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
{
memcpy(dst, src, count * sizeof(pgd_t));
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
if (kaiser_enabled) {
/* Clone the shadow pgd part as well */
memcpy(native_get_shadow_pgd(dst),
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -106,7 +106,7 @@ static inline void native_pud_clear(pud_
native_set_pud(pud, native_make_pud(0));
}
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
extern pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd);
static inline pgd_t *native_get_shadow_pgd(pgd_t *pgdp)
@@ -127,7 +127,7 @@ static inline pgd_t *native_get_shadow_p
BUILD_BUG_ON(1);
return NULL;
}
-#endif /* CONFIG_KAISER */
+#endif /* CONFIG_PAGE_TABLE_ISOLATION */
static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
{
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -144,7 +144,7 @@
#define X86_CR3_PCID_MASK (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_MASK)
#define X86_CR3_PCID_ASID_KERN (_AC(0x0,UL))
-#if defined(CONFIG_KAISER) && defined(CONFIG_X86_64)
+#if defined(CONFIG_PAGE_TABLE_ISOLATION) && defined(CONFIG_X86_64)
/* Let X86_CR3_PCID_ASID_USER be usable for the X86_CR3_PCID_NOFLUSH bit */
#define X86_CR3_PCID_ASID_USER (_AC(0x80,UL))
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -136,7 +136,7 @@ static inline void cr4_set_bits_and_upda
* Declare a couple of kaiser interfaces here for convenience,
* to avoid the need for asm/kaiser.h in unexpected places.
*/
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
extern int kaiser_enabled;
extern void kaiser_setup_pcid(void);
extern void kaiser_flush_tlb_on_return_to_user(void);
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -405,7 +405,7 @@ GLOBAL(early_recursion_flag)
.balign PAGE_SIZE; \
GLOBAL(name)
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
/*
* Each PGD needs to be 8k long and 8k aligned. We do not
* ever go out to userspace with these, so we do not
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -38,4 +38,4 @@ obj-$(CONFIG_NUMA_EMU) += numa_emulatio
obj-$(CONFIG_X86_INTEL_MPX) += mpx.o
obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o
obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
-obj-$(CONFIG_KAISER) += kaiser.o
+obj-$(CONFIG_PAGE_TABLE_ISOLATION) += kaiser.o
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -189,6 +189,6 @@ void __meminit init_trampoline(void)
*pud_tramp = *pud;
}
- /* Avoid set_pgd(), in case it's complicated by CONFIG_KAISER */
+ /* Avoid set_pgd(), in case it's complicated by CONFIG_PAGE_TABLE_ISOLATION */
trampoline_pgd_entry = __pgd(_KERNPG_TABLE | __pa(pud_page_tramp));
}
--- a/include/linux/kaiser.h
+++ b/include/linux/kaiser.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_KAISER_H
#define _LINUX_KAISER_H
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
#include <asm/kaiser.h>
static inline int kaiser_map_thread_stack(void *stack)
@@ -24,7 +24,7 @@ static inline void kaiser_unmap_thread_s
#else
/*
- * These stubs are used whenever CONFIG_KAISER is off, which
+ * These stubs are used whenever CONFIG_PAGE_TABLE_ISOLATION is off, which
* includes architectures that support KAISER, but have it disabled.
*/
@@ -48,5 +48,5 @@ static inline void kaiser_unmap_thread_s
{
}
-#endif /* !CONFIG_KAISER */
+#endif /* !CONFIG_PAGE_TABLE_ISOLATION */
#endif /* _LINUX_KAISER_H */
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -35,7 +35,7 @@
#endif
-#ifdef CONFIG_KAISER
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
#define USER_MAPPED_SECTION "..user_mapped"
#else
#define USER_MAPPED_SECTION ""
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -31,7 +31,7 @@ config SECURITY
If you are unsure how to answer this question, answer N.
-config KAISER
+config PAGE_TABLE_ISOLATION
bool "Remove the kernel mapping in user mode"
default y
depends on X86_64 && SMP
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -198,7 +198,7 @@
#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
-#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_KAISER w/o nokaiser */
+#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Kosina <[email protected]>
Kaiser cannot be used on paravirtualized MMUs (namely reading and writing CR3).
This does not work with KAISER as the CR3 switch from and to user space PGD
would require to map the whole XEN_PV machinery into both.
More importantly, enabling KAISER on Xen PV doesn't make too much sense, as PV
guests use distinct %cr3 values for kernel and user already.
Signed-off-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -263,6 +263,9 @@ void __init kaiser_check_boottime_disabl
char arg[5];
int ret;
+ if (boot_cpu_has(X86_FEATURE_XENPV))
+ goto silent_disable;
+
ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg));
if (ret > 0) {
if (!strncmp(arg, "on", 2))
@@ -290,6 +293,8 @@ enable:
disable:
pr_info("Kernel/User page tables isolation: disabled\n");
+
+silent_disable:
kaiser_enabled = 0;
setup_clear_cpu_cap(X86_FEATURE_KAISER);
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <[email protected]>
... before the first use of kaiser_enabled as otherwise funky
things happen:
about to get started...
(XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000]
(XEN) Pagetable walk from ffff88022a449090:
(XEN) L4[0x110] = 0000000229e0e067 0000000000001e0e
(XEN) L3[0x008] = 0000000000000000 ffffffffffffffff
(XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08
entry.o#create_bounce_frame+0x135/0x14d
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
(XEN) ----[ Xen-4.9.1_02-3.21 x86_64 debug=n Not tainted ]----
(XEN) CPU: 0
(XEN) RIP: e033:[<ffffffff81007460>]
(XEN) RFLAGS: 0000000000000286 EM: 1 CONTEXT: pv guest (d0v0)
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/kaiser.h | 2 ++
arch/x86/kernel/setup.c | 7 +++++++
arch/x86/mm/kaiser.c | 2 --
3 files changed, 9 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -96,8 +96,10 @@ DECLARE_PER_CPU(unsigned long, x86_cr3_p
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
extern int kaiser_enabled;
+extern void __init kaiser_check_boottime_disable(void);
#else
#define kaiser_enabled 0
+static inline void __init kaiser_check_boottime_disable(void) {}
#endif /* CONFIG_KAISER */
/*
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -114,6 +114,7 @@
#include <asm/microcode.h>
#include <asm/mmu_context.h>
#include <asm/kaslr.h>
+#include <asm/kaiser.h>
/*
* max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1019,6 +1020,12 @@ void __init setup_arch(char **cmdline_p)
*/
init_hypervisor_platform();
+ /*
+ * This needs to happen right after XENPV is set on xen and
+ * kaiser_enabled is checked below in cleanup_highmap().
+ */
+ kaiser_check_boottime_disable();
+
x86_init.resources.probe_roms();
/* after parse_early_param, so could debug it */
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -310,8 +310,6 @@ void __init kaiser_init(void)
{
int cpu;
- kaiser_check_boottime_disable();
-
if (!kaiser_enabled)
return;
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <[email protected]>
commit a035795499ca1c2bd1928808d1a156eda1420383 upstream
native_flush_tlb_single() will be changed with the upcoming
PAGE_TABLE_ISOLATION feature. This requires to have more code in
there than INVLPG.
Remove the paravirt patching for it.
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Laight <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: Eduardo Valentin <[email protected]>
Cc: Greg KH <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/paravirt_patch_64.c | 2 --
1 file changed, 2 deletions(-)
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -9,7 +9,6 @@ DEF_NATIVE(pv_irq_ops, save_fl, "pushfq;
DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
-DEF_NATIVE(pv_mmu_ops, flush_tlb_single, "invlpg (%rdi)");
DEF_NATIVE(pv_cpu_ops, clts, "clts");
DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd");
@@ -59,7 +58,6 @@ unsigned native_patch(u8 type, u16 clobb
PATCH_SITE(pv_mmu_ops, read_cr3);
PATCH_SITE(pv_mmu_ops, write_cr3);
PATCH_SITE(pv_cpu_ops, clts);
- PATCH_SITE(pv_mmu_ops, flush_tlb_single);
PATCH_SITE(pv_cpu_ops, wbinvd);
#if defined(CONFIG_PARAVIRT_SPINLOCKS)
case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Kaiser only needs to map one page of the stack; and
kernel/fork.c did not build on powerpc (no __PAGE_KERNEL).
It's all cleaner if linux/kaiser.h provides kaiser_map_thread_stack()
and kaiser_unmap_thread_stack() wrappers around asm/kaiser.h's
kaiser_add_mapping() and kaiser_remove_mapping(). And use
linux/kaiser.h in init/main.c to avoid the #ifdefs there.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/kaiser.h | 40 +++++++++++++++++++++++++++++++++-------
init/main.c | 6 +-----
kernel/fork.c | 7 ++-----
3 files changed, 36 insertions(+), 17 deletions(-)
--- a/include/linux/kaiser.h
+++ b/include/linux/kaiser.h
@@ -1,26 +1,52 @@
-#ifndef _INCLUDE_KAISER_H
-#define _INCLUDE_KAISER_H
+#ifndef _LINUX_KAISER_H
+#define _LINUX_KAISER_H
#ifdef CONFIG_KAISER
#include <asm/kaiser.h>
+
+static inline int kaiser_map_thread_stack(void *stack)
+{
+ /*
+ * Map that page of kernel stack on which we enter from user context.
+ */
+ return kaiser_add_mapping((unsigned long)stack +
+ THREAD_SIZE - PAGE_SIZE, PAGE_SIZE, __PAGE_KERNEL);
+}
+
+static inline void kaiser_unmap_thread_stack(void *stack)
+{
+ /*
+ * Note: may be called even when kaiser_map_thread_stack() failed.
+ */
+ kaiser_remove_mapping((unsigned long)stack +
+ THREAD_SIZE - PAGE_SIZE, PAGE_SIZE);
+}
#else
/*
* These stubs are used whenever CONFIG_KAISER is off, which
- * includes architectures that support KAISER, but have it
- * disabled.
+ * includes architectures that support KAISER, but have it disabled.
*/
static inline void kaiser_init(void)
{
}
-static inline void kaiser_remove_mapping(unsigned long start, unsigned long size)
+static inline int kaiser_add_mapping(unsigned long addr,
+ unsigned long size, unsigned long flags)
+{
+ return 0;
+}
+static inline void kaiser_remove_mapping(unsigned long start,
+ unsigned long size)
{
}
-static inline int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
+static inline int kaiser_map_thread_stack(void *stack)
{
return 0;
}
+static inline void kaiser_unmap_thread_stack(void *stack)
+{
+}
#endif /* !CONFIG_KAISER */
-#endif /* _INCLUDE_KAISER_H */
+#endif /* _LINUX_KAISER_H */
--- a/init/main.c
+++ b/init/main.c
@@ -80,15 +80,13 @@
#include <linux/integrity.h>
#include <linux/proc_ns.h>
#include <linux/io.h>
+#include <linux/kaiser.h>
#include <asm/io.h>
#include <asm/bugs.h>
#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
-#ifdef CONFIG_KAISER
-#include <asm/kaiser.h>
-#endif
static int kernel_init(void *);
@@ -476,9 +474,7 @@ static void __init mm_init(void)
pgtable_init();
vmalloc_init();
ioremap_huge_init();
-#ifdef CONFIG_KAISER
kaiser_init();
-#endif
}
asmlinkage __visible void __init start_kernel(void)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -212,12 +212,9 @@ static unsigned long *alloc_thread_stack
#endif
}
-extern void kaiser_remove_mapping(unsigned long start_addr, unsigned long size);
static inline void free_thread_stack(struct task_struct *tsk)
{
-#ifdef CONFIG_KAISER
- kaiser_remove_mapping((unsigned long)tsk->stack, THREAD_SIZE);
-#endif
+ kaiser_unmap_thread_stack(tsk->stack);
#ifdef CONFIG_VMAP_STACK
if (task_stack_vm_area(tsk)) {
unsigned long flags;
@@ -501,7 +498,7 @@ static struct task_struct *dup_task_stru
*/
tsk->stack = stack;
- err= kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL);
+ err= kaiser_map_thread_stack(tsk->stack);
if (err)
goto free_stack;
#ifdef CONFIG_VMAP_STACK
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dave Hansen <[email protected]>
Merged fixes and cleanups, rebased to 4.9.51 tree (no 5-level paging).
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 105 ++++++++++-
arch/x86/include/asm/kaiser.h | 43 ++--
arch/x86/include/asm/pgtable.h | 18 +
arch/x86/include/asm/pgtable_64.h | 48 ++++-
arch/x86/include/asm/pgtable_types.h | 6
arch/x86/kernel/espfix_64.c | 13 -
arch/x86/kernel/head_64.S | 19 +-
arch/x86/kernel/ldt.c | 27 ++
arch/x86/kernel/tracepoint.c | 2
arch/x86/mm/kaiser.c | 317 +++++++++++++++++++++++++----------
arch/x86/mm/pageattr.c | 63 +++++-
arch/x86/mm/pgtable.c | 40 +---
include/linux/kaiser.h | 26 ++
kernel/fork.c | 9
security/Kconfig | 5
15 files changed, 551 insertions(+), 190 deletions(-)
create mode 100644 include/linux/kaiser.h
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -230,6 +230,13 @@ entry_SYSCALL_64_fastpath:
movq RIP(%rsp), %rcx
movq EFLAGS(%rsp), %r11
RESTORE_C_REGS_EXCEPT_RCX_R11
+ /*
+ * This opens a window where we have a user CR3, but are
+ * running in the kernel. This makes using the CS
+ * register useless for telling whether or not we need to
+ * switch CR3 in NMIs. Normal interrupts are OK because
+ * they are off here.
+ */
SWITCH_USER_CR3
movq RSP(%rsp), %rsp
USERGS_SYSRET64
@@ -326,11 +333,25 @@ return_from_SYSCALL_64:
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
RESTORE_C_REGS_EXCEPT_RCX_R11
+ /*
+ * This opens a window where we have a user CR3, but are
+ * running in the kernel. This makes using the CS
+ * register useless for telling whether or not we need to
+ * switch CR3 in NMIs. Normal interrupts are OK because
+ * they are off here.
+ */
SWITCH_USER_CR3
movq RSP(%rsp), %rsp
USERGS_SYSRET64
opportunistic_sysret_failed:
+ /*
+ * This opens a window where we have a user CR3, but are
+ * running in the kernel. This makes using the CS
+ * register useless for telling whether or not we need to
+ * switch CR3 in NMIs. Normal interrupts are OK because
+ * they are off here.
+ */
SWITCH_USER_CR3
SWAPGS
jmp restore_c_regs_and_iret
@@ -1087,6 +1108,13 @@ ENTRY(error_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ /*
+ * error_entry() always returns with a kernel gsbase and
+ * CR3. We must also have a kernel CR3/gsbase before
+ * calling TRACE_IRQS_*. Just unconditionally switch to
+ * the kernel CR3 here.
+ */
+ SWITCH_KERNEL_CR3
xorl %ebx, %ebx
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@@ -1096,7 +1124,6 @@ ENTRY(error_entry)
* from user mode due to an IRET fault.
*/
SWAPGS
- SWITCH_KERNEL_CR3
.Lerror_entry_from_usermode_after_swapgs:
/*
@@ -1148,7 +1175,6 @@ ENTRY(error_entry)
* Switch to kernel gsbase:
*/
SWAPGS
- SWITCH_KERNEL_CR3
/*
* Pretend that the exception came from user mode: set up pt_regs
@@ -1249,7 +1275,10 @@ ENTRY(nmi)
*/
SWAPGS_UNSAFE_STACK
- SWITCH_KERNEL_CR3_NO_STACK
+ /*
+ * percpu variables are mapped with user CR3, so no need
+ * to switch CR3 here.
+ */
cld
movq %rsp, %rdx
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
@@ -1283,14 +1312,33 @@ ENTRY(nmi)
movq %rsp, %rdi
movq $-1, %rsi
+#ifdef CONFIG_KAISER
+ /* Unconditionally use kernel CR3 for do_nmi() */
+ /* %rax is saved above, so OK to clobber here */
+ movq %cr3, %rax
+ pushq %rax
+#ifdef CONFIG_KAISER_REAL_SWITCH
+ andq $(~0x1000), %rax
+#endif
+ movq %rax, %cr3
+#endif
call do_nmi
+ /*
+ * Unconditionally restore CR3. I know we return to
+ * kernel code that needs user CR3, but do we ever return
+ * to "user mode" where we need the kernel CR3?
+ */
+#ifdef CONFIG_KAISER
+ popq %rax
+ mov %rax, %cr3
+#endif
/*
* Return back to user mode. We must *not* do the normal exit
- * work, because we don't want to enable interrupts. Fortunately,
- * do_nmi doesn't modify pt_regs.
+ * work, because we don't want to enable interrupts. Do not
+ * switch to user CR3: we might be going back to kernel code
+ * that had a user CR3 set.
*/
- SWITCH_USER_CR3
SWAPGS
jmp restore_c_regs_and_iret
@@ -1486,23 +1534,54 @@ end_repeat_nmi:
ALLOC_PT_GPREGS_ON_STACK
/*
- * Use paranoid_entry to handle SWAPGS, but no need to use paranoid_exit
- * as we should not be calling schedule in NMI context.
- * Even with normal interrupts enabled. An NMI should not be
- * setting NEED_RESCHED or anything that normal interrupts and
- * exceptions might do.
+ * Use the same approach as paranoid_entry to handle SWAPGS, but
+ * without CR3 handling since we do that differently in NMIs. No
+ * need to use paranoid_exit as we should not be calling schedule
+ * in NMI context. Even with normal interrupts enabled. An NMI
+ * should not be setting NEED_RESCHED or anything that normal
+ * interrupts and exceptions might do.
*/
- call paranoid_entry
+ cld
+ SAVE_C_REGS
+ SAVE_EXTRA_REGS
+ movl $1, %ebx
+ movl $MSR_GS_BASE, %ecx
+ rdmsr
+ testl %edx, %edx
+ js 1f /* negative -> in kernel */
+ SWAPGS
+ xorl %ebx, %ebx
+1:
+#ifdef CONFIG_KAISER
+ /* Unconditionally use kernel CR3 for do_nmi() */
+ /* %rax is saved above, so OK to clobber here */
+ movq %cr3, %rax
+ pushq %rax
+#ifdef CONFIG_KAISER_REAL_SWITCH
+ andq $(~0x1000), %rax
+#endif
+ movq %rax, %cr3
+#endif
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
movq %rsp, %rdi
+ addq $8, %rdi /* point %rdi at ptregs, fixed up for CR3 */
movq $-1, %rsi
call do_nmi
+ /*
+ * Unconditionally restore CR3. We might be returning to
+ * kernel code that needs user CR3, like just just before
+ * a sysret.
+ */
+#ifdef CONFIG_KAISER
+ popq %rax
+ mov %rax, %cr3
+#endif
testl %ebx, %ebx /* swapgs needed? */
jnz nmi_restore
nmi_swapgs:
- SWITCH_USER_CR3_NO_STACK
+ /* We fixed up CR3 above, so no need to switch it here */
SWAPGS_UNSAFE_STACK
nmi_restore:
RESTORE_EXTRA_REGS
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -16,13 +16,17 @@
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
+#ifdef CONFIG_KAISER_REAL_SWITCH
andq $(~0x1000), \reg
+#endif
movq \reg, %cr3
.endm
.macro _SWITCH_TO_USER_CR3 reg
movq %cr3, \reg
+#ifdef CONFIG_KAISER_REAL_SWITCH
orq $(0x1000), \reg
+#endif
movq \reg, %cr3
.endm
@@ -65,48 +69,53 @@ movq PER_CPU_VAR(unsafe_stack_register_b
.endm
#endif /* CONFIG_KAISER */
+
#else /* __ASSEMBLY__ */
#ifdef CONFIG_KAISER
-// Upon kernel/user mode switch, it may happen that
-// the address space has to be switched before the registers have been stored.
-// To change the address space, another register is needed.
-// A register therefore has to be stored/restored.
-//
-DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+/*
+ * Upon kernel/user mode switch, it may happen that the address
+ * space has to be switched before the registers have been
+ * stored. To change the address space, another register is
+ * needed. A register therefore has to be stored/restored.
+*/
-#endif /* CONFIG_KAISER */
+DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
/**
- * shadowmem_add_mapping - map a virtual memory part to the shadow mapping
+ * kaiser_add_mapping - map a virtual memory part to the shadow (user) mapping
* @addr: the start address of the range
* @size: the size of the range
* @flags: The mapping flags of the pages
*
- * the mapping is done on a global scope, so no bigger synchronization has to be done.
- * the pages have to be manually unmapped again when they are not needed any longer.
+ * The mapping is done on a global scope, so no bigger
+ * synchronization has to be done. the pages have to be
+ * manually unmapped again when they are not needed any longer.
*/
-extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
+extern int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
/**
- * shadowmem_remove_mapping - unmap a virtual memory part of the shadow mapping
+ * kaiser_remove_mapping - unmap a virtual memory part of the shadow mapping
* @addr: the start address of the range
* @size: the size of the range
*/
extern void kaiser_remove_mapping(unsigned long start, unsigned long size);
/**
- * shadowmem_initialize_mapping - Initalize the shadow mapping
+ * kaiser_initialize_mapping - Initalize the shadow mapping
*
- * most parts of the shadow mapping can be mapped upon boot time.
- * only the thread stacks have to be mapped on runtime.
- * the mapped regions are not unmapped at all.
+ * Most parts of the shadow mapping can be mapped upon boot
+ * time. Only per-process things like the thread stacks
+ * or a new LDT have to be mapped at runtime. These boot-
+ * time mappings are permanent and nevertunmapped.
*/
extern void kaiser_init(void);
-#endif
+#endif /* CONFIG_KAISER */
+
+#endif /* __ASSEMBLY */
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -690,7 +690,17 @@ static inline pud_t *pud_offset(pgd_t *p
static inline int pgd_bad(pgd_t pgd)
{
- return (pgd_flags(pgd) & ~_PAGE_USER) != _KERNPG_TABLE;
+ pgdval_t ignore_flags = _PAGE_USER;
+ /*
+ * We set NX on KAISER pgds that map userspace memory so
+ * that userspace can not meaningfully use the kernel
+ * page table by accident; it will fault on the first
+ * instruction it tries to run. See native_set_pgd().
+ */
+ if (IS_ENABLED(CONFIG_KAISER))
+ ignore_flags |= _PAGE_NX;
+
+ return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE;
}
static inline int pgd_none(pgd_t pgd)
@@ -905,8 +915,10 @@ static inline void clone_pgd_range(pgd_t
{
memcpy(dst, src, count * sizeof(pgd_t));
#ifdef CONFIG_KAISER
- // clone the shadow pgd part as well
- memcpy(native_get_shadow_pgd(dst), native_get_shadow_pgd(src), count * sizeof(pgd_t));
+ /* Clone the shadow pgd part as well */
+ memcpy(native_get_shadow_pgd(dst),
+ native_get_shadow_pgd(src),
+ count * sizeof(pgd_t));
#endif
}
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -107,26 +107,58 @@ static inline void native_pud_clear(pud_
}
#ifdef CONFIG_KAISER
-static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp) {
+static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp)
+{
return (pgd_t *)(void*)((unsigned long)(void*)pgdp | (unsigned long)PAGE_SIZE);
}
-static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp) {
+static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp)
+{
return (pgd_t *)(void*)((unsigned long)(void*)pgdp & ~(unsigned long)PAGE_SIZE);
}
+#else
+static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp)
+{
+ BUILD_BUG_ON(1);
+ return NULL;
+}
+static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp)
+{
+ return pgdp;
+}
#endif /* CONFIG_KAISER */
+/*
+ * Page table pages are page-aligned. The lower half of the top
+ * level is used for userspace and the top half for the kernel.
+ * This returns true for user pages that need to get copied into
+ * both the user and kernel copies of the page tables, and false
+ * for kernel pages that should only be in the kernel copy.
+ */
+static inline bool is_userspace_pgd(void *__ptr)
+{
+ unsigned long ptr = (unsigned long)__ptr;
+
+ return ((ptr % PAGE_SIZE) < (PAGE_SIZE / 2));
+}
+
static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
{
#ifdef CONFIG_KAISER
- // We know that a pgd is page aligned.
- // Therefore the lower indices have to be mapped to user space.
- // These pages are mapped to the shadow mapping.
- if ((((unsigned long)pgdp) % PAGE_SIZE) < (PAGE_SIZE / 2)) {
+ pteval_t extra_kern_pgd_flags = 0;
+ /* Do we need to also populate the shadow pgd? */
+ if (is_userspace_pgd(pgdp)) {
native_get_shadow_pgd(pgdp)->pgd = pgd.pgd;
+ /*
+ * Even if the entry is *mapping* userspace, ensure
+ * that userspace can not use it. This way, if we
+ * get out to userspace running on the kernel CR3,
+ * userspace will crash instead of running.
+ */
+ extra_kern_pgd_flags = _PAGE_NX;
}
-
- pgdp->pgd = pgd.pgd & ~_PAGE_USER;
+ pgdp->pgd = pgd.pgd;
+ pgdp->pgd |= extra_kern_pgd_flags;
#else /* CONFIG_KAISER */
*pgdp = pgd;
#endif
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -48,7 +48,7 @@
#ifdef CONFIG_KAISER
#define _PAGE_GLOBAL (_AT(pteval_t, 0))
#else
-#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
+#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
#endif
#define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
#define _PAGE_SOFTW2 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW2)
@@ -123,11 +123,7 @@
#define _PAGE_DEVMAP (_AT(pteval_t, 0))
#endif
-#ifdef CONFIG_KAISER
-#define _PAGE_PROTNONE (_AT(pteval_t, 0))
-#else
#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
-#endif
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_DIRTY)
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -127,11 +127,14 @@ void __init init_espfix_bsp(void)
/* Install the espfix pud into the kernel page directory */
pgd_p = &init_level4_pgt[pgd_index(ESPFIX_BASE_ADDR)];
pgd_populate(&init_mm, pgd_p, (pud_t *)espfix_pud_page);
-#ifdef CONFIG_KAISER
- // add the esp stack pud to the shadow mapping here.
- // This can be done directly, because the fixup stack has its own pud
- set_pgd(native_get_shadow_pgd(pgd_p), __pgd(_PAGE_TABLE | __pa((pud_t *)espfix_pud_page)));
-#endif
+ /*
+ * Just copy the top-level PGD that is mapping the espfix
+ * area to ensure it is mapped into the shadow user page
+ * tables.
+ */
+ if (IS_ENABLED(CONFIG_KAISER))
+ set_pgd(native_get_shadow_pgd(pgd_p),
+ __pgd(_KERNPG_TABLE | __pa((pud_t *)espfix_pud_page)));
/* Randomize the locations */
init_espfix_random();
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -406,11 +406,24 @@ GLOBAL(early_recursion_flag)
GLOBAL(name)
#ifdef CONFIG_KAISER
+/*
+ * Each PGD needs to be 8k long and 8k aligned. We do not
+ * ever go out to userspace with these, so we do not
+ * strictly *need* the second page, but this allows us to
+ * have a single set_pgd() implementation that does not
+ * need to worry about whether it has 4k or 8k to work
+ * with.
+ *
+ * This ensures PGDs are 8k long:
+ */
+#define KAISER_USER_PGD_FILL 512
+/* This ensures they are 8k-aligned: */
#define NEXT_PGD_PAGE(name) \
.balign 2 * PAGE_SIZE; \
GLOBAL(name)
#else
#define NEXT_PGD_PAGE(name) NEXT_PAGE(name)
+#define KAISER_USER_PGD_FILL 0
#endif
/* Automate the creation of 1 to 1 mapping pmd entries */
@@ -425,6 +438,7 @@ GLOBAL(name)
NEXT_PGD_PAGE(early_level4_pgt)
.fill 511,8,0
.quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
+ .fill KAISER_USER_PGD_FILL,8,0
NEXT_PAGE(early_dynamic_pgts)
.fill 512*EARLY_DYNAMIC_PAGE_TABLES,8,0
@@ -433,7 +447,8 @@ NEXT_PAGE(early_dynamic_pgts)
#ifndef CONFIG_XEN
NEXT_PGD_PAGE(init_level4_pgt)
- .fill 2*512,8,0
+ .fill 512,8,0
+ .fill KAISER_USER_PGD_FILL,8,0
#else
NEXT_PGD_PAGE(init_level4_pgt)
.quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
@@ -442,6 +457,7 @@ NEXT_PGD_PAGE(init_level4_pgt)
.org init_level4_pgt + L4_START_KERNEL*8, 0
/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
.quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
+ .fill KAISER_USER_PGD_FILL,8,0
NEXT_PAGE(level3_ident_pgt)
.quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
@@ -452,6 +468,7 @@ NEXT_PAGE(level2_ident_pgt)
*/
PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
#endif
+ .fill KAISER_USER_PGD_FILL,8,0
NEXT_PAGE(level3_kernel_pgt)
.fill L3_START_KERNEL,8,0
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -18,6 +18,7 @@
#include <linux/uaccess.h>
#include <asm/ldt.h>
+#include <asm/kaiser.h>
#include <asm/desc.h>
#include <asm/mmu_context.h>
#include <asm/syscalls.h>
@@ -34,11 +35,21 @@ static void flush_ldt(void *current_mm)
set_ldt(pc->ldt->entries, pc->ldt->size);
}
+static void __free_ldt_struct(struct ldt_struct *ldt)
+{
+ if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
+ vfree(ldt->entries);
+ else
+ free_page((unsigned long)ldt->entries);
+ kfree(ldt);
+}
+
/* The caller must call finalize_ldt_struct on the result. LDT starts zeroed. */
static struct ldt_struct *alloc_ldt_struct(int size)
{
struct ldt_struct *new_ldt;
int alloc_size;
+ int ret = 0;
if (size > LDT_ENTRIES)
return NULL;
@@ -66,6 +77,14 @@ static struct ldt_struct *alloc_ldt_stru
return NULL;
}
+ // FIXME: make kaiser_add_mapping() return an error code
+ // when it fails
+ kaiser_add_mapping((unsigned long)new_ldt->entries, alloc_size,
+ __PAGE_KERNEL);
+ if (ret) {
+ __free_ldt_struct(new_ldt);
+ return NULL;
+ }
new_ldt->size = size;
return new_ldt;
}
@@ -92,12 +111,10 @@ static void free_ldt_struct(struct ldt_s
if (likely(!ldt))
return;
+ kaiser_remove_mapping((unsigned long)ldt->entries,
+ ldt->size * LDT_ENTRY_SIZE);
paravirt_free_ldt(ldt->entries, ldt->size);
- if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE)
- vfree(ldt->entries);
- else
- free_page((unsigned long)ldt->entries);
- kfree(ldt);
+ __free_ldt_struct(ldt);
}
/*
--- a/arch/x86/kernel/tracepoint.c
+++ b/arch/x86/kernel/tracepoint.c
@@ -9,10 +9,12 @@
#include <linux/atomic.h>
atomic_t trace_idt_ctr = ATOMIC_INIT(0);
+__aligned(PAGE_SIZE)
struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
(unsigned long) trace_idt_table };
/* No need to be aligned, but done to keep all IDTs defined the same way. */
+__aligned(PAGE_SIZE)
gate_desc trace_idt_table[NR_VECTORS] __page_aligned_bss;
static int trace_irq_vector_refcount;
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -1,160 +1,305 @@
-
-
+#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/bug.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
-
#include <linux/uaccess.h>
+
+#include <asm/kaiser.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/desc.h>
#ifdef CONFIG_KAISER
__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+/*
+ * At runtime, the only things we map are some things for CPU
+ * hotplug, and stacks for new processes. No two CPUs will ever
+ * be populating the same addresses, so we only need to ensure
+ * that we protect between two CPUs trying to allocate and
+ * populate the same page table page.
+ *
+ * Only take this lock when doing a set_p[4um]d(), but it is not
+ * needed for doing a set_pte(). We assume that only the *owner*
+ * of a given allocation will be doing this for _their_
+ * allocation.
+ *
+ * This ensures that once a system has been running for a while
+ * and there have been stacks all over and these page tables
+ * are fully populated, there will be no further acquisitions of
+ * this lock.
+ */
+static DEFINE_SPINLOCK(shadow_table_allocation_lock);
-/**
- * Get the real ppn from a address in kernel mapping.
- * @param address The virtual adrress
- * @return the physical address
+/*
+ * Returns -1 on error.
*/
-static inline unsigned long get_pa_from_mapping (unsigned long address)
+static inline unsigned long get_pa_from_mapping(unsigned long vaddr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
- pgd = pgd_offset_k(address);
- BUG_ON(pgd_none(*pgd) || pgd_large(*pgd));
+ pgd = pgd_offset_k(vaddr);
+ /*
+ * We made all the kernel PGDs present in kaiser_init().
+ * We expect them to stay that way.
+ */
+ BUG_ON(pgd_none(*pgd));
+ /*
+ * PGDs are either 512GB or 128TB on all x86_64
+ * configurations. We don't handle these.
+ */
+ BUG_ON(pgd_large(*pgd));
+
+ pud = pud_offset(pgd, vaddr);
+ if (pud_none(*pud)) {
+ WARN_ON_ONCE(1);
+ return -1;
+ }
- pud = pud_offset(pgd, address);
- BUG_ON(pud_none(*pud));
+ if (pud_large(*pud))
+ return (pud_pfn(*pud) << PAGE_SHIFT) | (vaddr & ~PUD_PAGE_MASK);
- if (pud_large(*pud)) {
- return (pud_pfn(*pud) << PAGE_SHIFT) | (address & ~PUD_PAGE_MASK);
+ pmd = pmd_offset(pud, vaddr);
+ if (pmd_none(*pmd)) {
+ WARN_ON_ONCE(1);
+ return -1;
}
- pmd = pmd_offset(pud, address);
- BUG_ON(pmd_none(*pmd));
+ if (pmd_large(*pmd))
+ return (pmd_pfn(*pmd) << PAGE_SHIFT) | (vaddr & ~PMD_PAGE_MASK);
- if (pmd_large(*pmd)) {
- return (pmd_pfn(*pmd) << PAGE_SHIFT) | (address & ~PMD_PAGE_MASK);
+ pte = pte_offset_kernel(pmd, vaddr);
+ if (pte_none(*pte)) {
+ WARN_ON_ONCE(1);
+ return -1;
}
- pte = pte_offset_kernel(pmd, address);
- BUG_ON(pte_none(*pte));
-
- return (pte_pfn(*pte) << PAGE_SHIFT) | (address & ~PAGE_MASK);
+ return (pte_pfn(*pte) << PAGE_SHIFT) | (vaddr & ~PAGE_MASK);
}
-void _kaiser_copy (unsigned long start_addr, unsigned long size,
- unsigned long flags)
+/*
+ * This is a relatively normal page table walk, except that it
+ * also tries to allocate page tables pages along the way.
+ *
+ * Returns a pointer to a PTE on success, or NULL on failure.
+ */
+static pte_t *kaiser_pagetable_walk(unsigned long address, bool is_atomic)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
- unsigned long address;
- unsigned long end_addr = start_addr + size;
- unsigned long target_address;
+ pud_t *pud;
+ pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(address));
+ gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- for (address = PAGE_ALIGN(start_addr - (PAGE_SIZE - 1));
- address < PAGE_ALIGN(end_addr); address += PAGE_SIZE) {
- target_address = get_pa_from_mapping(address);
+ might_sleep();
+ if (is_atomic) {
+ gfp &= ~GFP_KERNEL;
+ gfp |= __GFP_HIGH | __GFP_ATOMIC;
+ }
- pgd = native_get_shadow_pgd(pgd_offset_k(address));
+ if (pgd_none(*pgd)) {
+ WARN_ONCE(1, "All shadow pgds should have been populated");
+ return NULL;
+ }
+ BUILD_BUG_ON(pgd_large(*pgd) != 0);
- BUG_ON(pgd_none(*pgd) && "All shadow pgds should be mapped at this time\n");
- BUG_ON(pgd_large(*pgd));
+ pud = pud_offset(pgd, address);
+ /* The shadow page tables do not use large mappings: */
+ if (pud_large(*pud)) {
+ WARN_ON(1);
+ return NULL;
+ }
+ if (pud_none(*pud)) {
+ unsigned long new_pmd_page = __get_free_page(gfp);
+ if (!new_pmd_page)
+ return NULL;
+ spin_lock(&shadow_table_allocation_lock);
+ if (pud_none(*pud))
+ set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
+ else
+ free_page(new_pmd_page);
+ spin_unlock(&shadow_table_allocation_lock);
+ }
- pud = pud_offset(pgd, address);
- if (pud_none(*pud)) {
- set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd_alloc_one(0, address))));
- }
- BUG_ON(pud_large(*pud));
+ pmd = pmd_offset(pud, address);
+ /* The shadow page tables do not use large mappings: */
+ if (pmd_large(*pmd)) {
+ WARN_ON(1);
+ return NULL;
+ }
+ if (pmd_none(*pmd)) {
+ unsigned long new_pte_page = __get_free_page(gfp);
+ if (!new_pte_page)
+ return NULL;
+ spin_lock(&shadow_table_allocation_lock);
+ if (pmd_none(*pmd))
+ set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page)));
+ else
+ free_page(new_pte_page);
+ spin_unlock(&shadow_table_allocation_lock);
+ }
- pmd = pmd_offset(pud, address);
- if (pmd_none(*pmd)) {
- set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte_alloc_one_kernel(0, address))));
- }
- BUG_ON(pmd_large(*pmd));
+ return pte_offset_kernel(pmd, address);
+}
- pte = pte_offset_kernel(pmd, address);
+int kaiser_add_user_map(const void *__start_addr, unsigned long size,
+ unsigned long flags)
+{
+ int ret = 0;
+ pte_t *pte;
+ unsigned long start_addr = (unsigned long )__start_addr;
+ unsigned long address = start_addr & PAGE_MASK;
+ unsigned long end_addr = PAGE_ALIGN(start_addr + size);
+ unsigned long target_address;
+
+ for (;address < end_addr; address += PAGE_SIZE) {
+ target_address = get_pa_from_mapping(address);
+ if (target_address == -1) {
+ ret = -EIO;
+ break;
+ }
+ pte = kaiser_pagetable_walk(address, false);
if (pte_none(*pte)) {
set_pte(pte, __pte(flags | target_address));
} else {
- BUG_ON(__pa(pte_page(*pte)) != target_address);
+ pte_t tmp;
+ set_pte(&tmp, __pte(flags | target_address));
+ WARN_ON_ONCE(!pte_same(*pte, tmp));
}
}
+ return ret;
}
-// at first, add a pmd for every pgd entry in the shadowmem-kernel-part of the kernel mapping
-static inline void __init _kaiser_init(void)
+static int kaiser_add_user_map_ptrs(const void *start, const void *end, unsigned long flags)
+{
+ unsigned long size = end - start;
+
+ return kaiser_add_user_map(start, size, flags);
+}
+
+/*
+ * Ensure that the top level of the (shadow) page tables are
+ * entirely populated. This ensures that all processes that get
+ * forked have the same entries. This way, we do not have to
+ * ever go set up new entries in older processes.
+ *
+ * Note: we never free these, so there are no updates to them
+ * after this.
+ */
+static void __init kaiser_init_all_pgds(void)
{
pgd_t *pgd;
int i = 0;
pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0));
for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) {
- set_pgd(pgd + i, __pgd(_PAGE_TABLE |__pa(pud_alloc_one(0, 0))));
+ pgd_t new_pgd;
+ pud_t *pud = pud_alloc_one(&init_mm, PAGE_OFFSET + i * PGDIR_SIZE);
+ if (!pud) {
+ WARN_ON(1);
+ break;
+ }
+ new_pgd = __pgd(_KERNPG_TABLE |__pa(pud));
+ /*
+ * Make sure not to stomp on some other pgd entry.
+ */
+ if (!pgd_none(pgd[i])) {
+ WARN_ON(1);
+ continue;
+ }
+ set_pgd(pgd + i, new_pgd);
}
}
+#define kaiser_add_user_map_early(start, size, flags) do { \
+ int __ret = kaiser_add_user_map(start, size, flags); \
+ WARN_ON(__ret); \
+} while (0)
+
+#define kaiser_add_user_map_ptrs_early(start, end, flags) do { \
+ int __ret = kaiser_add_user_map_ptrs(start, end, flags); \
+ WARN_ON(__ret); \
+} while (0)
+
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
-spinlock_t shadow_table_lock;
+/*
+ * If anything in here fails, we will likely die on one of the
+ * first kernel->user transitions and init will die. But, we
+ * will have most of the kernel up by then and should be able to
+ * get a clean warning out of it. If we BUG_ON() here, we run
+ * the risk of being before we have good console output.
+ */
void __init kaiser_init(void)
{
int cpu;
- spin_lock_init(&shadow_table_lock);
-
- spin_lock(&shadow_table_lock);
- _kaiser_init();
+ kaiser_init_all_pgds();
for_each_possible_cpu(cpu) {
- // map the per cpu user variables
- _kaiser_copy(
- (unsigned long) (__per_cpu_user_mapped_start + per_cpu_offset(cpu)),
- (unsigned long) __per_cpu_user_mapped_end - (unsigned long) __per_cpu_user_mapped_start,
- __PAGE_KERNEL);
- }
-
- // map the entry/exit text section, which is responsible to switch between user- and kernel mode
- _kaiser_copy(
- (unsigned long) __entry_text_start,
- (unsigned long) __entry_text_end - (unsigned long) __entry_text_start,
- __PAGE_KERNEL_RX);
-
- // the fixed map address of the idt_table
- _kaiser_copy(
- (unsigned long) idt_descr.address,
- sizeof(gate_desc) * NR_VECTORS,
- __PAGE_KERNEL_RO);
+ void *percpu_vaddr = __per_cpu_user_mapped_start +
+ per_cpu_offset(cpu);
+ unsigned long percpu_sz = __per_cpu_user_mapped_end -
+ __per_cpu_user_mapped_start;
+ kaiser_add_user_map_early(percpu_vaddr, percpu_sz,
+ __PAGE_KERNEL);
+ }
- spin_unlock(&shadow_table_lock);
+ /*
+ * Map the entry/exit text section, which is needed at
+ * switches from user to and from kernel.
+ */
+ kaiser_add_user_map_ptrs_early(__entry_text_start, __entry_text_end,
+ __PAGE_KERNEL_RX);
+
+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
+ kaiser_add_user_map_ptrs_early(__irqentry_text_start,
+ __irqentry_text_end,
+ __PAGE_KERNEL_RX);
+#endif
+ kaiser_add_user_map_early((void *)idt_descr.address,
+ sizeof(gate_desc) * NR_VECTORS,
+ __PAGE_KERNEL_RO);
+#ifdef CONFIG_TRACING
+ kaiser_add_user_map_early(&trace_idt_descr,
+ sizeof(trace_idt_descr),
+ __PAGE_KERNEL);
+ kaiser_add_user_map_early(&trace_idt_table,
+ sizeof(gate_desc) * NR_VECTORS,
+ __PAGE_KERNEL);
+#endif
+ kaiser_add_user_map_early(&debug_idt_descr, sizeof(debug_idt_descr),
+ __PAGE_KERNEL);
+ kaiser_add_user_map_early(&debug_idt_table,
+ sizeof(gate_desc) * NR_VECTORS,
+ __PAGE_KERNEL);
}
+extern void unmap_pud_range_nofree(pgd_t *pgd, unsigned long start, unsigned long end);
// add a mapping to the shadow-mapping, and synchronize the mappings
-void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
+int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
{
- spin_lock(&shadow_table_lock);
- _kaiser_copy(addr, size, flags);
- spin_unlock(&shadow_table_lock);
+ return kaiser_add_user_map((const void *)addr, size, flags);
}
-extern void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end);
void kaiser_remove_mapping(unsigned long start, unsigned long size)
{
- pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(start));
- spin_lock(&shadow_table_lock);
- do {
- unmap_pud_range(pgd, start, start + size);
- } while (pgd++ != native_get_shadow_pgd(pgd_offset_k(start + size)));
- spin_unlock(&shadow_table_lock);
+ unsigned long end = start + size;
+ unsigned long addr;
+
+ for (addr = start; addr < end; addr += PGDIR_SIZE) {
+ pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(addr));
+ /*
+ * unmap_p4d_range() handles > P4D_SIZE unmaps,
+ * so no need to trim 'end'.
+ */
+ unmap_pud_range_nofree(pgd, addr, end);
+ }
}
#endif /* CONFIG_KAISER */
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -52,6 +52,7 @@ static DEFINE_SPINLOCK(cpa_lock);
#define CPA_FLUSHTLB 1
#define CPA_ARRAY 2
#define CPA_PAGES_ARRAY 4
+#define CPA_FREE_PAGETABLES 8
#ifdef CONFIG_PROC_FS
static unsigned long direct_pages_count[PG_LEVEL_NUM];
@@ -729,10 +730,13 @@ static int split_large_page(struct cpa_d
return 0;
}
-static bool try_to_free_pte_page(pte_t *pte)
+static bool try_to_free_pte_page(struct cpa_data *cpa, pte_t *pte)
{
int i;
+ if (!(cpa->flags & CPA_FREE_PAGETABLES))
+ return false;
+
for (i = 0; i < PTRS_PER_PTE; i++)
if (!pte_none(pte[i]))
return false;
@@ -741,10 +745,13 @@ static bool try_to_free_pte_page(pte_t *
return true;
}
-static bool try_to_free_pmd_page(pmd_t *pmd)
+static bool try_to_free_pmd_page(struct cpa_data *cpa, pmd_t *pmd)
{
int i;
+ if (!(cpa->flags & CPA_FREE_PAGETABLES))
+ return false;
+
for (i = 0; i < PTRS_PER_PMD; i++)
if (!pmd_none(pmd[i]))
return false;
@@ -753,7 +760,9 @@ static bool try_to_free_pmd_page(pmd_t *
return true;
}
-static bool unmap_pte_range(pmd_t *pmd, unsigned long start, unsigned long end)
+static bool unmap_pte_range(struct cpa_data *cpa, pmd_t *pmd,
+ unsigned long start,
+ unsigned long end)
{
pte_t *pte = pte_offset_kernel(pmd, start);
@@ -764,22 +773,23 @@ static bool unmap_pte_range(pmd_t *pmd,
pte++;
}
- if (try_to_free_pte_page((pte_t *)pmd_page_vaddr(*pmd))) {
+ if (try_to_free_pte_page(cpa, (pte_t *)pmd_page_vaddr(*pmd))) {
pmd_clear(pmd);
return true;
}
return false;
}
-static void __unmap_pmd_range(pud_t *pud, pmd_t *pmd,
+static void __unmap_pmd_range(struct cpa_data *cpa, pud_t *pud, pmd_t *pmd,
unsigned long start, unsigned long end)
{
- if (unmap_pte_range(pmd, start, end))
- if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud)))
+ if (unmap_pte_range(cpa, pmd, start, end))
+ if (try_to_free_pmd_page(cpa, (pmd_t *)pud_page_vaddr(*pud)))
pud_clear(pud);
}
-static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end)
+static void unmap_pmd_range(struct cpa_data *cpa, pud_t *pud,
+ unsigned long start, unsigned long end)
{
pmd_t *pmd = pmd_offset(pud, start);
@@ -790,7 +800,7 @@ static void unmap_pmd_range(pud_t *pud,
unsigned long next_page = (start + PMD_SIZE) & PMD_MASK;
unsigned long pre_end = min_t(unsigned long, end, next_page);
- __unmap_pmd_range(pud, pmd, start, pre_end);
+ __unmap_pmd_range(cpa, pud, pmd, start, pre_end);
start = pre_end;
pmd++;
@@ -803,7 +813,8 @@ static void unmap_pmd_range(pud_t *pud,
if (pmd_large(*pmd))
pmd_clear(pmd);
else
- __unmap_pmd_range(pud, pmd, start, start + PMD_SIZE);
+ __unmap_pmd_range(cpa, pud, pmd,
+ start, start + PMD_SIZE);
start += PMD_SIZE;
pmd++;
@@ -813,17 +824,19 @@ static void unmap_pmd_range(pud_t *pud,
* 4K leftovers?
*/
if (start < end)
- return __unmap_pmd_range(pud, pmd, start, end);
+ return __unmap_pmd_range(cpa, pud, pmd, start, end);
/*
* Try again to free the PMD page if haven't succeeded above.
*/
if (!pud_none(*pud))
- if (try_to_free_pmd_page((pmd_t *)pud_page_vaddr(*pud)))
+ if (try_to_free_pmd_page(cpa, (pmd_t *)pud_page_vaddr(*pud)))
pud_clear(pud);
}
-void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
+static void __unmap_pud_range(struct cpa_data *cpa, pgd_t *pgd,
+ unsigned long start,
+ unsigned long end)
{
pud_t *pud = pud_offset(pgd, start);
@@ -834,7 +847,7 @@ void unmap_pud_range(pgd_t *pgd, unsigne
unsigned long next_page = (start + PUD_SIZE) & PUD_MASK;
unsigned long pre_end = min_t(unsigned long, end, next_page);
- unmap_pmd_range(pud, start, pre_end);
+ unmap_pmd_range(cpa, pud, start, pre_end);
start = pre_end;
pud++;
@@ -848,7 +861,7 @@ void unmap_pud_range(pgd_t *pgd, unsigne
if (pud_large(*pud))
pud_clear(pud);
else
- unmap_pmd_range(pud, start, start + PUD_SIZE);
+ unmap_pmd_range(cpa, pud, start, start + PUD_SIZE);
start += PUD_SIZE;
pud++;
@@ -858,7 +871,7 @@ void unmap_pud_range(pgd_t *pgd, unsigne
* 2M leftovers?
*/
if (start < end)
- unmap_pmd_range(pud, start, end);
+ unmap_pmd_range(cpa, pud, start, end);
/*
* No need to try to free the PUD page because we'll free it in
@@ -866,6 +879,24 @@ void unmap_pud_range(pgd_t *pgd, unsigne
*/
}
+static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
+{
+ struct cpa_data cpa = {
+ .flags = CPA_FREE_PAGETABLES,
+ };
+
+ __unmap_pud_range(&cpa, pgd, start, end);
+}
+
+void unmap_pud_range_nofree(pgd_t *pgd, unsigned long start, unsigned long end)
+{
+ struct cpa_data cpa = {
+ .flags = 0,
+ };
+
+ __unmap_pud_range(&cpa, pgd, start, end);
+}
+
static int alloc_pte_page(pmd_t *pmd)
{
pte_t *pte = (pte_t *)get_zeroed_page(GFP_KERNEL | __GFP_NOTRACK);
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -344,40 +344,26 @@ static inline void _pgd_free(pgd_t *pgd)
kmem_cache_free(pgd_cache, pgd);
}
#else
-static inline pgd_t *_pgd_alloc(void)
-{
-#ifdef CONFIG_KAISER
- // Instead of one PML4, we aquire two PML4s and, thus, an 8kb-aligned memory
- // block. Therefore, we have to allocate at least 3 pages. However, the
- // __get_free_pages returns us 4 pages. Hence, we store the base pointer at
- // the beginning of the page of our 8kb-aligned memory block in order to
- // correctly free it afterwars.
- unsigned long pages = __get_free_pages(PGALLOC_GFP, get_order(4*PAGE_SIZE));
-
- if(native_get_normal_pgd((pgd_t*) pages) == (pgd_t*) pages)
- {
- *((unsigned long*)(pages + 2 * PAGE_SIZE)) = pages;
- return (pgd_t *) pages;
- }
- else
- {
- *((unsigned long*)(pages + 3 * PAGE_SIZE)) = pages;
- return (pgd_t *) (pages + PAGE_SIZE);
- }
+#ifdef CONFIG_KAISER
+/*
+ * Instead of one pmd, we aquire two pmds. Being order-1, it is
+ * both 8k in size and 8k-aligned. That lets us just flip bit 12
+ * in a pointer to swap between the two 4k halves.
+ */
+#define PGD_ALLOCATION_ORDER 1
#else
- return (pgd_t *)__get_free_page(PGALLOC_GFP);
+#define PGD_ALLOCATION_ORDER 0
#endif
+
+static inline pgd_t *_pgd_alloc(void)
+{
+ return (pgd_t *)__get_free_pages(PGALLOC_GFP, PGD_ALLOCATION_ORDER);
}
static inline void _pgd_free(pgd_t *pgd)
{
-#ifdef CONFIG_KAISER
- unsigned long pages = *((unsigned long*) ((char*) pgd + 2 * PAGE_SIZE));
- free_pages(pages, get_order(4*PAGE_SIZE));
-#else
- free_page((unsigned long)pgd);
-#endif
+ free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
}
#endif /* CONFIG_X86_PAE */
--- /dev/null
+++ b/include/linux/kaiser.h
@@ -0,0 +1,26 @@
+#ifndef _INCLUDE_KAISER_H
+#define _INCLUDE_KAISER_H
+
+#ifdef CONFIG_KAISER
+#include <asm/kaiser.h>
+#else
+
+/*
+ * These stubs are used whenever CONFIG_KAISER is off, which
+ * includes architectures that support KAISER, but have it
+ * disabled.
+ */
+
+static inline void kaiser_init(void)
+{
+}
+static inline void kaiser_remove_mapping(unsigned long start, unsigned long size)
+{
+}
+static inline int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
+{
+ return 0;
+}
+
+#endif /* !CONFIG_KAISER */
+#endif /* _INCLUDE_KAISER_H */
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -58,6 +58,7 @@
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/freezer.h>
+#include <linux/kaiser.h>
#include <linux/delayacct.h>
#include <linux/taskstats_kern.h>
#include <linux/random.h>
@@ -472,7 +473,6 @@ void set_task_stack_end_magic(struct tas
*stackend = STACK_END_MAGIC; /* for overflow detection */
}
-extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
@@ -500,9 +500,10 @@ static struct task_struct *dup_task_stru
* functions again.
*/
tsk->stack = stack;
-#ifdef CONFIG_KAISER
- kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL);
-#endif
+
+ err= kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL);
+ if (err)
+ goto free_stack;
#ifdef CONFIG_VMAP_STACK
tsk->stack_vm_area = stack_vm_area;
#endif
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -32,12 +32,17 @@ config SECURITY
If you are unsure how to answer this question, answer N.
config KAISER
bool "Remove the kernel mapping in user mode"
+ default y
depends on X86_64
depends on !PARAVIRT
help
This enforces a strict kernel and user space isolation in order to close
hardware side channels on kernel address information.
+config KAISER_REAL_SWITCH
+ bool "KAISER: actually switch page tables"
+ default y
+
config SECURITYFS
bool "Enable the securityfs filesystem"
help
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Richard Fellner <[email protected]>
This patch introduces our implementation of KAISER (Kernel Address Isolation to
have Side-channels Efficiently Removed), a kernel isolation technique to close
hardware side channels on kernel address information.
More information about the patch can be found on:
https://github.com/IAIK/KAISER
From: Richard Fellner <[email protected]>
From: Daniel Gruss <[email protected]>
Subject: [PATCH 4.9 04/39] [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode
Date: Thu, 4 May 2017 14:26:50 +0200
Link: http://marc.info/?l=linux-kernel&m=149390087310405&w=2
Kaiser-4.10-SHA1: c4b1831d44c6144d3762ccc72f0c4e71a0c713e5
To: <[email protected]>
To: <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
Cc: Michael Schwarz <[email protected]>
Cc: Richard Fellner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: <[email protected]>
Cc: <[email protected]>
After several recent works [1,2,3] KASLR on x86_64 was basically
considered dead by many researchers. We have been working on an
efficient but effective fix for this problem and found that not mapping
the kernel space when running in user mode is the solution to this
problem [4] (the corresponding paper [5] will be presented at ESSoS17).
With this RFC patch we allow anybody to configure their kernel with the
flag CONFIG_KAISER to add our defense mechanism.
If there are any questions we would love to answer them.
We also appreciate any comments!
Cheers,
Daniel (+ the KAISER team from Graz University of Technology)
[1] http://www.ieee-security.org/TC/SP2013/papers/4977a191.pdf
[2] https://www.blackhat.com/docs/us-16/materials/us-16-Fogh-Using-Undocumented-CPU-Behaviour-To-See-Into-Kernel-Mode-And-Break-KASLR-In-The-Process.pdf
[3] https://www.blackhat.com/docs/us-16/materials/us-16-Jang-Breaking-Kernel-Address-Space-Layout-Randomization-KASLR-With-Intel-TSX.pdf
[4] https://github.com/IAIK/KAISER
[5] https://gruss.cc/files/kaiser.pdf
[patch based also on
https://raw.githubusercontent.com/IAIK/KAISER/master/KAISER/0001-KAISER-Kernel-Address-Isolation.patch]
Signed-off-by: Richard Fellner <[email protected]>
Signed-off-by: Moritz Lipp <[email protected]>
Signed-off-by: Daniel Gruss <[email protected]>
Signed-off-by: Michael Schwarz <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 17 +++
arch/x86/entry/entry_64_compat.S | 7 +
arch/x86/include/asm/hw_irq.h | 2
arch/x86/include/asm/kaiser.h | 113 ++++++++++++++++++++++++
arch/x86/include/asm/pgtable.h | 4
arch/x86/include/asm/pgtable_64.h | 21 ++++
arch/x86/include/asm/pgtable_types.h | 12 ++
arch/x86/include/asm/processor.h | 7 +
arch/x86/kernel/cpu/common.c | 4
arch/x86/kernel/espfix_64.c | 6 +
arch/x86/kernel/head_64.S | 16 ++-
arch/x86/kernel/irqinit.c | 2
arch/x86/kernel/process.c | 2
arch/x86/mm/Makefile | 2
arch/x86/mm/kaiser.c | 160 +++++++++++++++++++++++++++++++++++
arch/x86/mm/pageattr.c | 2
arch/x86/mm/pgtable.c | 26 +++++
include/asm-generic/vmlinux.lds.h | 11 ++
include/linux/percpu-defs.h | 30 ++++++
init/main.c | 6 +
kernel/fork.c | 8 +
security/Kconfig | 7 +
22 files changed, 449 insertions(+), 16 deletions(-)
create mode 100644 arch/x86/include/asm/kaiser.h
create mode 100644 arch/x86/mm/kaiser.c
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -36,6 +36,7 @@
#include <asm/smap.h>
#include <asm/pgtable_types.h>
#include <asm/export.h>
+#include <asm/kaiser.h>
#include <linux/err.h>
/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
@@ -146,6 +147,7 @@ ENTRY(entry_SYSCALL_64)
* it is too small to ever cause noticeable irq latency.
*/
SWAPGS_UNSAFE_STACK
+ SWITCH_KERNEL_CR3_NO_STACK
/*
* A hypervisor implementation might want to use a label
* after the swapgs, so that it can do the swapgs
@@ -228,6 +230,7 @@ entry_SYSCALL_64_fastpath:
movq RIP(%rsp), %rcx
movq EFLAGS(%rsp), %r11
RESTORE_C_REGS_EXCEPT_RCX_R11
+ SWITCH_USER_CR3
movq RSP(%rsp), %rsp
USERGS_SYSRET64
@@ -323,10 +326,12 @@ return_from_SYSCALL_64:
syscall_return_via_sysret:
/* rcx and r11 are already restored (see code above) */
RESTORE_C_REGS_EXCEPT_RCX_R11
+ SWITCH_USER_CR3
movq RSP(%rsp), %rsp
USERGS_SYSRET64
opportunistic_sysret_failed:
+ SWITCH_USER_CR3
SWAPGS
jmp restore_c_regs_and_iret
END(entry_SYSCALL_64)
@@ -424,6 +429,7 @@ ENTRY(ret_from_fork)
movq %rsp, %rdi
call syscall_return_slowpath /* returns with IRQs disabled */
TRACE_IRQS_ON /* user mode is traced as IRQS on */
+ SWITCH_USER_CR3
SWAPGS
jmp restore_regs_and_iret
@@ -478,6 +484,7 @@ END(irq_entries_start)
* tracking that we're in kernel mode.
*/
SWAPGS
+ SWITCH_KERNEL_CR3
/*
* We need to tell lockdep that IRQs are off. We can't do this until
@@ -535,6 +542,7 @@ GLOBAL(retint_user)
mov %rsp,%rdi
call prepare_exit_to_usermode
TRACE_IRQS_IRETQ
+ SWITCH_USER_CR3
SWAPGS
jmp restore_regs_and_iret
@@ -612,6 +620,7 @@ native_irq_return_ldt:
pushq %rdi /* Stash user RDI */
SWAPGS
+ SWITCH_KERNEL_CR3
movq PER_CPU_VAR(espfix_waddr), %rdi
movq %rax, (0*8)(%rdi) /* user RAX */
movq (1*8)(%rsp), %rax /* user RIP */
@@ -638,6 +647,7 @@ native_irq_return_ldt:
* still points to an RO alias of the ESPFIX stack.
*/
orq PER_CPU_VAR(espfix_stack), %rax
+ SWITCH_USER_CR3
SWAPGS
movq %rax, %rsp
@@ -1034,6 +1044,7 @@ ENTRY(paranoid_entry)
testl %edx, %edx
js 1f /* negative -> in kernel */
SWAPGS
+ SWITCH_KERNEL_CR3
xorl %ebx, %ebx
1: ret
END(paranoid_entry)
@@ -1056,6 +1067,7 @@ ENTRY(paranoid_exit)
testl %ebx, %ebx /* swapgs needed? */
jnz paranoid_exit_no_swapgs
TRACE_IRQS_IRETQ
+ SWITCH_USER_CR3_NO_STACK
SWAPGS_UNSAFE_STACK
jmp paranoid_exit_restore
paranoid_exit_no_swapgs:
@@ -1084,6 +1096,7 @@ ENTRY(error_entry)
* from user mode due to an IRET fault.
*/
SWAPGS
+ SWITCH_KERNEL_CR3
.Lerror_entry_from_usermode_after_swapgs:
/*
@@ -1135,6 +1148,7 @@ ENTRY(error_entry)
* Switch to kernel gsbase:
*/
SWAPGS
+ SWITCH_KERNEL_CR3
/*
* Pretend that the exception came from user mode: set up pt_regs
@@ -1235,6 +1249,7 @@ ENTRY(nmi)
*/
SWAPGS_UNSAFE_STACK
+ SWITCH_KERNEL_CR3_NO_STACK
cld
movq %rsp, %rdx
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
@@ -1275,6 +1290,7 @@ ENTRY(nmi)
* work, because we don't want to enable interrupts. Fortunately,
* do_nmi doesn't modify pt_regs.
*/
+ SWITCH_USER_CR3
SWAPGS
jmp restore_c_regs_and_iret
@@ -1486,6 +1502,7 @@ end_repeat_nmi:
testl %ebx, %ebx /* swapgs needed? */
jnz nmi_restore
nmi_swapgs:
+ SWITCH_USER_CR3_NO_STACK
SWAPGS_UNSAFE_STACK
nmi_restore:
RESTORE_EXTRA_REGS
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -13,6 +13,7 @@
#include <asm/irqflags.h>
#include <asm/asm.h>
#include <asm/smap.h>
+#include <asm/kaiser.h>
#include <linux/linkage.h>
#include <linux/err.h>
@@ -48,6 +49,7 @@
ENTRY(entry_SYSENTER_compat)
/* Interrupts are off on entry. */
SWAPGS_UNSAFE_STACK
+ SWITCH_KERNEL_CR3_NO_STACK
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/*
@@ -184,6 +186,7 @@ ENDPROC(entry_SYSENTER_compat)
ENTRY(entry_SYSCALL_compat)
/* Interrupts are off on entry. */
SWAPGS_UNSAFE_STACK
+ SWITCH_KERNEL_CR3_NO_STACK
/* Stash user ESP and switch to the kernel stack. */
movl %esp, %r8d
@@ -259,6 +262,7 @@ sysret32_from_system_call:
xorq %r8, %r8
xorq %r9, %r9
xorq %r10, %r10
+ SWITCH_USER_CR3
movq RSP-ORIG_RAX(%rsp), %rsp
swapgs
sysretl
@@ -297,7 +301,7 @@ ENTRY(entry_INT80_compat)
PARAVIRT_ADJUST_EXCEPTION_FRAME
ASM_CLAC /* Do this early to minimize exposure */
SWAPGS
-
+ SWITCH_KERNEL_CR3_NO_STACK
/*
* User tracing code (ptrace or signal handlers) might assume that
* the saved RAX contains a 32-bit number when we're invoking a 32-bit
@@ -338,6 +342,7 @@ ENTRY(entry_INT80_compat)
/* Go back to user mode. */
TRACE_IRQS_ON
+ SWITCH_USER_CR3_NO_STACK
SWAPGS
jmp restore_regs_and_iret
END(entry_INT80_compat)
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -178,7 +178,7 @@ extern char irq_entries_start[];
#define VECTOR_RETRIGGERED ((void *)~0UL)
typedef struct irq_desc* vector_irq_t[NR_VECTORS];
-DECLARE_PER_CPU(vector_irq_t, vector_irq);
+DECLARE_PER_CPU_USER_MAPPED(vector_irq_t, vector_irq);
#endif /* !ASSEMBLY_ */
--- /dev/null
+++ b/arch/x86/include/asm/kaiser.h
@@ -0,0 +1,113 @@
+#ifndef _ASM_X86_KAISER_H
+#define _ASM_X86_KAISER_H
+
+/* This file includes the definitions for the KAISER feature.
+ * KAISER is a counter measure against x86_64 side channel attacks on the kernel virtual memory.
+ * It has a shodow-pgd for every process. the shadow-pgd has a minimalistic kernel-set mapped,
+ * but includes the whole user memory. Within a kernel context switch, or when an interrupt is handled,
+ * the pgd is switched to the normal one. When the system switches to user mode, the shadow pgd is enabled.
+ * By this, the virtual memory chaches are freed, and the user may not attack the whole kernel memory.
+ *
+ * A minimalistic kernel mapping holds the parts needed to be mapped in user mode, as the entry/exit functions
+ * of the user space, or the stacks.
+ */
+#ifdef __ASSEMBLY__
+#ifdef CONFIG_KAISER
+
+.macro _SWITCH_TO_KERNEL_CR3 reg
+movq %cr3, \reg
+andq $(~0x1000), \reg
+movq \reg, %cr3
+.endm
+
+.macro _SWITCH_TO_USER_CR3 reg
+movq %cr3, \reg
+orq $(0x1000), \reg
+movq \reg, %cr3
+.endm
+
+.macro SWITCH_KERNEL_CR3
+pushq %rax
+_SWITCH_TO_KERNEL_CR3 %rax
+popq %rax
+.endm
+
+.macro SWITCH_USER_CR3
+pushq %rax
+_SWITCH_TO_USER_CR3 %rax
+popq %rax
+.endm
+
+.macro SWITCH_KERNEL_CR3_NO_STACK
+movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
+_SWITCH_TO_KERNEL_CR3 %rax
+movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
+.endm
+
+
+.macro SWITCH_USER_CR3_NO_STACK
+
+movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
+_SWITCH_TO_USER_CR3 %rax
+movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
+
+.endm
+
+#else /* CONFIG_KAISER */
+
+.macro SWITCH_KERNEL_CR3 reg
+.endm
+.macro SWITCH_USER_CR3 reg
+.endm
+.macro SWITCH_USER_CR3_NO_STACK
+.endm
+.macro SWITCH_KERNEL_CR3_NO_STACK
+.endm
+
+#endif /* CONFIG_KAISER */
+#else /* __ASSEMBLY__ */
+
+
+#ifdef CONFIG_KAISER
+// Upon kernel/user mode switch, it may happen that
+// the address space has to be switched before the registers have been stored.
+// To change the address space, another register is needed.
+// A register therefore has to be stored/restored.
+//
+DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+
+#endif /* CONFIG_KAISER */
+
+/**
+ * shadowmem_add_mapping - map a virtual memory part to the shadow mapping
+ * @addr: the start address of the range
+ * @size: the size of the range
+ * @flags: The mapping flags of the pages
+ *
+ * the mapping is done on a global scope, so no bigger synchronization has to be done.
+ * the pages have to be manually unmapped again when they are not needed any longer.
+ */
+extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
+
+
+/**
+ * shadowmem_remove_mapping - unmap a virtual memory part of the shadow mapping
+ * @addr: the start address of the range
+ * @size: the size of the range
+ */
+extern void kaiser_remove_mapping(unsigned long start, unsigned long size);
+
+/**
+ * shadowmem_initialize_mapping - Initalize the shadow mapping
+ *
+ * most parts of the shadow mapping can be mapped upon boot time.
+ * only the thread stacks have to be mapped on runtime.
+ * the mapped regions are not unmapped at all.
+ */
+extern void kaiser_init(void);
+
+#endif
+
+
+
+#endif /* _ASM_X86_KAISER_H */
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -904,6 +904,10 @@ static inline void pmdp_set_wrprotect(st
static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
{
memcpy(dst, src, count * sizeof(pgd_t));
+#ifdef CONFIG_KAISER
+ // clone the shadow pgd part as well
+ memcpy(native_get_shadow_pgd(dst), native_get_shadow_pgd(src), count * sizeof(pgd_t));
+#endif
}
#define PTE_SHIFT ilog2(PTRS_PER_PTE)
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -106,9 +106,30 @@ static inline void native_pud_clear(pud_
native_set_pud(pud, native_make_pud(0));
}
+#ifdef CONFIG_KAISER
+static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp) {
+ return (pgd_t *)(void*)((unsigned long)(void*)pgdp | (unsigned long)PAGE_SIZE);
+}
+
+static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp) {
+ return (pgd_t *)(void*)((unsigned long)(void*)pgdp & ~(unsigned long)PAGE_SIZE);
+}
+#endif /* CONFIG_KAISER */
+
static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
{
+#ifdef CONFIG_KAISER
+ // We know that a pgd is page aligned.
+ // Therefore the lower indices have to be mapped to user space.
+ // These pages are mapped to the shadow mapping.
+ if ((((unsigned long)pgdp) % PAGE_SIZE) < (PAGE_SIZE / 2)) {
+ native_get_shadow_pgd(pgdp)->pgd = pgd.pgd;
+ }
+
+ pgdp->pgd = pgd.pgd & ~_PAGE_USER;
+#else /* CONFIG_KAISER */
*pgdp = pgd;
+#endif
}
static inline void native_pgd_clear(pgd_t *pgd)
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -45,7 +45,11 @@
#define _PAGE_ACCESSED (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
#define _PAGE_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
#define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
-#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
+#ifdef CONFIG_KAISER
+#define _PAGE_GLOBAL (_AT(pteval_t, 0))
+#else
+#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
+#endif
#define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
#define _PAGE_SOFTW2 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW2)
#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
@@ -119,7 +123,11 @@
#define _PAGE_DEVMAP (_AT(pteval_t, 0))
#endif
-#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
+#ifdef CONFIG_KAISER
+#define _PAGE_PROTNONE (_AT(pteval_t, 0))
+#else
+#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
+#endif
#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
_PAGE_ACCESSED | _PAGE_DIRTY)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -308,7 +308,7 @@ struct tss_struct {
} ____cacheline_aligned;
-DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
+DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(struct tss_struct, cpu_tss);
#ifdef CONFIG_X86_32
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
@@ -335,6 +335,11 @@ union irq_stack_union {
char gs_base[40];
unsigned long stack_canary;
};
+
+ struct {
+ char irq_stack_pointer[64];
+ char unused[IRQ_STACK_SIZE - 64];
+ };
};
DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible;
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -93,7 +93,7 @@ static const struct cpu_dev default_cpu
static const struct cpu_dev *this_cpu = &default_cpu;
-DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
+DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(struct gdt_page, gdt_page) = { .gdt = {
#ifdef CONFIG_X86_64
/*
* We need valid kernel segments for data and code in long mode too
@@ -1365,7 +1365,7 @@ static const unsigned int exception_stac
[DEBUG_STACK - 1] = DEBUG_STKSZ
};
-static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
+DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(char, exception_stacks
[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
/* May not be marked __init: used by software suspend */
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -41,6 +41,7 @@
#include <asm/pgalloc.h>
#include <asm/setup.h>
#include <asm/espfix.h>
+#include <asm/kaiser.h>
/*
* Note: we only need 6*8 = 48 bytes for the espfix stack, but round
@@ -126,6 +127,11 @@ void __init init_espfix_bsp(void)
/* Install the espfix pud into the kernel page directory */
pgd_p = &init_level4_pgt[pgd_index(ESPFIX_BASE_ADDR)];
pgd_populate(&init_mm, pgd_p, (pud_t *)espfix_pud_page);
+#ifdef CONFIG_KAISER
+ // add the esp stack pud to the shadow mapping here.
+ // This can be done directly, because the fixup stack has its own pud
+ set_pgd(native_get_shadow_pgd(pgd_p), __pgd(_PAGE_TABLE | __pa((pud_t *)espfix_pud_page)));
+#endif
/* Randomize the locations */
init_espfix_random();
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -405,6 +405,14 @@ GLOBAL(early_recursion_flag)
.balign PAGE_SIZE; \
GLOBAL(name)
+#ifdef CONFIG_KAISER
+#define NEXT_PGD_PAGE(name) \
+ .balign 2 * PAGE_SIZE; \
+GLOBAL(name)
+#else
+#define NEXT_PGD_PAGE(name) NEXT_PAGE(name)
+#endif
+
/* Automate the creation of 1 to 1 mapping pmd entries */
#define PMDS(START, PERM, COUNT) \
i = 0 ; \
@@ -414,7 +422,7 @@ GLOBAL(name)
.endr
__INITDATA
-NEXT_PAGE(early_level4_pgt)
+NEXT_PGD_PAGE(early_level4_pgt)
.fill 511,8,0
.quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
@@ -424,10 +432,10 @@ NEXT_PAGE(early_dynamic_pgts)
.data
#ifndef CONFIG_XEN
-NEXT_PAGE(init_level4_pgt)
- .fill 512,8,0
+NEXT_PGD_PAGE(init_level4_pgt)
+ .fill 2*512,8,0
#else
-NEXT_PAGE(init_level4_pgt)
+NEXT_PGD_PAGE(init_level4_pgt)
.quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
.org init_level4_pgt + L4_PAGE_OFFSET*8, 0
.quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -51,7 +51,7 @@ static struct irqaction irq2 = {
.flags = IRQF_NO_THREAD,
};
-DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
+DEFINE_PER_CPU_USER_MAPPED(vector_irq_t, vector_irq) = {
[0 ... NR_VECTORS - 1] = VECTOR_UNUSED,
};
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -41,7 +41,7 @@
* section. Since TSS's are completely CPU-local, we want them
* on exact cacheline boundaries, to eliminate cacheline ping-pong.
*/
-__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
+__visible DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(struct tss_struct, cpu_tss) = {
.x86_tss = {
.sp0 = TOP_OF_INIT_STACK,
#ifdef CONFIG_X86_32
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -38,4 +38,4 @@ obj-$(CONFIG_NUMA_EMU) += numa_emulatio
obj-$(CONFIG_X86_INTEL_MPX) += mpx.o
obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o
obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o
-
+obj-$(CONFIG_KAISER) += kaiser.o
--- /dev/null
+++ b/arch/x86/mm/kaiser.c
@@ -0,0 +1,160 @@
+
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/bug.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+
+#include <linux/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/desc.h>
+#ifdef CONFIG_KAISER
+
+__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+
+/**
+ * Get the real ppn from a address in kernel mapping.
+ * @param address The virtual adrress
+ * @return the physical address
+ */
+static inline unsigned long get_pa_from_mapping (unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset_k(address);
+ BUG_ON(pgd_none(*pgd) || pgd_large(*pgd));
+
+ pud = pud_offset(pgd, address);
+ BUG_ON(pud_none(*pud));
+
+ if (pud_large(*pud)) {
+ return (pud_pfn(*pud) << PAGE_SHIFT) | (address & ~PUD_PAGE_MASK);
+ }
+
+ pmd = pmd_offset(pud, address);
+ BUG_ON(pmd_none(*pmd));
+
+ if (pmd_large(*pmd)) {
+ return (pmd_pfn(*pmd) << PAGE_SHIFT) | (address & ~PMD_PAGE_MASK);
+ }
+
+ pte = pte_offset_kernel(pmd, address);
+ BUG_ON(pte_none(*pte));
+
+ return (pte_pfn(*pte) << PAGE_SHIFT) | (address & ~PAGE_MASK);
+}
+
+void _kaiser_copy (unsigned long start_addr, unsigned long size,
+ unsigned long flags)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long address;
+ unsigned long end_addr = start_addr + size;
+ unsigned long target_address;
+
+ for (address = PAGE_ALIGN(start_addr - (PAGE_SIZE - 1));
+ address < PAGE_ALIGN(end_addr); address += PAGE_SIZE) {
+ target_address = get_pa_from_mapping(address);
+
+ pgd = native_get_shadow_pgd(pgd_offset_k(address));
+
+ BUG_ON(pgd_none(*pgd) && "All shadow pgds should be mapped at this time\n");
+ BUG_ON(pgd_large(*pgd));
+
+ pud = pud_offset(pgd, address);
+ if (pud_none(*pud)) {
+ set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd_alloc_one(0, address))));
+ }
+ BUG_ON(pud_large(*pud));
+
+ pmd = pmd_offset(pud, address);
+ if (pmd_none(*pmd)) {
+ set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte_alloc_one_kernel(0, address))));
+ }
+ BUG_ON(pmd_large(*pmd));
+
+ pte = pte_offset_kernel(pmd, address);
+ if (pte_none(*pte)) {
+ set_pte(pte, __pte(flags | target_address));
+ } else {
+ BUG_ON(__pa(pte_page(*pte)) != target_address);
+ }
+ }
+}
+
+// at first, add a pmd for every pgd entry in the shadowmem-kernel-part of the kernel mapping
+static inline void __init _kaiser_init(void)
+{
+ pgd_t *pgd;
+ int i = 0;
+
+ pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0));
+ for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) {
+ set_pgd(pgd + i, __pgd(_PAGE_TABLE |__pa(pud_alloc_one(0, 0))));
+ }
+}
+
+extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
+spinlock_t shadow_table_lock;
+void __init kaiser_init(void)
+{
+ int cpu;
+ spin_lock_init(&shadow_table_lock);
+
+ spin_lock(&shadow_table_lock);
+
+ _kaiser_init();
+
+ for_each_possible_cpu(cpu) {
+ // map the per cpu user variables
+ _kaiser_copy(
+ (unsigned long) (__per_cpu_user_mapped_start + per_cpu_offset(cpu)),
+ (unsigned long) __per_cpu_user_mapped_end - (unsigned long) __per_cpu_user_mapped_start,
+ __PAGE_KERNEL);
+ }
+
+ // map the entry/exit text section, which is responsible to switch between user- and kernel mode
+ _kaiser_copy(
+ (unsigned long) __entry_text_start,
+ (unsigned long) __entry_text_end - (unsigned long) __entry_text_start,
+ __PAGE_KERNEL_RX);
+
+ // the fixed map address of the idt_table
+ _kaiser_copy(
+ (unsigned long) idt_descr.address,
+ sizeof(gate_desc) * NR_VECTORS,
+ __PAGE_KERNEL_RO);
+
+ spin_unlock(&shadow_table_lock);
+}
+
+// add a mapping to the shadow-mapping, and synchronize the mappings
+void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
+{
+ spin_lock(&shadow_table_lock);
+ _kaiser_copy(addr, size, flags);
+ spin_unlock(&shadow_table_lock);
+}
+
+extern void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end);
+void kaiser_remove_mapping(unsigned long start, unsigned long size)
+{
+ pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(start));
+ spin_lock(&shadow_table_lock);
+ do {
+ unmap_pud_range(pgd, start, start + size);
+ } while (pgd++ != native_get_shadow_pgd(pgd_offset_k(start + size)));
+ spin_unlock(&shadow_table_lock);
+}
+#endif /* CONFIG_KAISER */
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -823,7 +823,7 @@ static void unmap_pmd_range(pud_t *pud,
pud_clear(pud);
}
-static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
+void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end)
{
pud_t *pud = pud_offset(pgd, start);
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -346,12 +346,38 @@ static inline void _pgd_free(pgd_t *pgd)
#else
static inline pgd_t *_pgd_alloc(void)
{
+#ifdef CONFIG_KAISER
+ // Instead of one PML4, we aquire two PML4s and, thus, an 8kb-aligned memory
+ // block. Therefore, we have to allocate at least 3 pages. However, the
+ // __get_free_pages returns us 4 pages. Hence, we store the base pointer at
+ // the beginning of the page of our 8kb-aligned memory block in order to
+ // correctly free it afterwars.
+
+ unsigned long pages = __get_free_pages(PGALLOC_GFP, get_order(4*PAGE_SIZE));
+
+ if(native_get_normal_pgd((pgd_t*) pages) == (pgd_t*) pages)
+ {
+ *((unsigned long*)(pages + 2 * PAGE_SIZE)) = pages;
+ return (pgd_t *) pages;
+ }
+ else
+ {
+ *((unsigned long*)(pages + 3 * PAGE_SIZE)) = pages;
+ return (pgd_t *) (pages + PAGE_SIZE);
+ }
+#else
return (pgd_t *)__get_free_page(PGALLOC_GFP);
+#endif
}
static inline void _pgd_free(pgd_t *pgd)
{
+#ifdef CONFIG_KAISER
+ unsigned long pages = *((unsigned long*) ((char*) pgd + 2 * PAGE_SIZE));
+ free_pages(pages, get_order(4*PAGE_SIZE));
+#else
free_page((unsigned long)pgd);
+#endif
}
#endif /* CONFIG_X86_PAE */
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -778,7 +778,16 @@
*/
#define PERCPU_INPUT(cacheline) \
VMLINUX_SYMBOL(__per_cpu_start) = .; \
- *(.data..percpu..first) \
+ \
+ VMLINUX_SYMBOL(__per_cpu_user_mapped_start) = .; \
+ *(.data..percpu..first) \
+ . = ALIGN(cacheline); \
+ *(.data..percpu..user_mapped) \
+ *(.data..percpu..user_mapped..shared_aligned) \
+ . = ALIGN(PAGE_SIZE); \
+ *(.data..percpu..user_mapped..page_aligned) \
+ VMLINUX_SYMBOL(__per_cpu_user_mapped_end) = .; \
+ \
. = ALIGN(PAGE_SIZE); \
*(.data..percpu..page_aligned) \
. = ALIGN(cacheline); \
--- a/include/linux/percpu-defs.h
+++ b/include/linux/percpu-defs.h
@@ -35,6 +35,12 @@
#endif
+#ifdef CONFIG_KAISER
+#define USER_MAPPED_SECTION "..user_mapped"
+#else
+#define USER_MAPPED_SECTION ""
+#endif
+
/*
* Base implementations of per-CPU variable declarations and definitions, where
* the section in which the variable is to be placed is provided by the
@@ -115,6 +121,12 @@
#define DEFINE_PER_CPU(type, name) \
DEFINE_PER_CPU_SECTION(type, name, "")
+#define DECLARE_PER_CPU_USER_MAPPED(type, name) \
+ DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
+
+#define DEFINE_PER_CPU_USER_MAPPED(type, name) \
+ DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION)
+
/*
* Declaration/definition used for per-CPU variables that must come first in
* the set of variables.
@@ -144,6 +156,14 @@
DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
____cacheline_aligned_in_smp
+#define DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
+ DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
+ ____cacheline_aligned_in_smp
+
+#define DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \
+ DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \
+ ____cacheline_aligned_in_smp
+
#define DECLARE_PER_CPU_ALIGNED(type, name) \
DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \
____cacheline_aligned
@@ -162,6 +182,16 @@
#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
DEFINE_PER_CPU_SECTION(type, name, "..page_aligned") \
__aligned(PAGE_SIZE)
+/*
+ * Declaration/definition used for per-CPU variables that must be page aligned and need to be mapped in user mode.
+ */
+#define DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
+ DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
+ __aligned(PAGE_SIZE)
+
+#define DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \
+ DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \
+ __aligned(PAGE_SIZE)
/*
* Declaration/definition used for per-CPU variables that must be read mostly.
--- a/init/main.c
+++ b/init/main.c
@@ -86,6 +86,9 @@
#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
+#ifdef CONFIG_KAISER
+#include <asm/kaiser.h>
+#endif
static int kernel_init(void *);
@@ -473,6 +476,9 @@ static void __init mm_init(void)
pgtable_init();
vmalloc_init();
ioremap_huge_init();
+#ifdef CONFIG_KAISER
+ kaiser_init();
+#endif
}
asmlinkage __visible void __init start_kernel(void)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -211,8 +211,12 @@ static unsigned long *alloc_thread_stack
#endif
}
+extern void kaiser_remove_mapping(unsigned long start_addr, unsigned long size);
static inline void free_thread_stack(struct task_struct *tsk)
{
+#ifdef CONFIG_KAISER
+ kaiser_remove_mapping((unsigned long)tsk->stack, THREAD_SIZE);
+#endif
#ifdef CONFIG_VMAP_STACK
if (task_stack_vm_area(tsk)) {
unsigned long flags;
@@ -468,6 +472,7 @@ void set_task_stack_end_magic(struct tas
*stackend = STACK_END_MAGIC; /* for overflow detection */
}
+extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
@@ -495,6 +500,9 @@ static struct task_struct *dup_task_stru
* functions again.
*/
tsk->stack = stack;
+#ifdef CONFIG_KAISER
+ kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL);
+#endif
#ifdef CONFIG_VMAP_STACK
tsk->stack_vm_area = stack_vm_area;
#endif
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -30,6 +30,13 @@ config SECURITY
model will be used.
If you are unsure how to answer this question, answer N.
+config KAISER
+ bool "Remove the kernel mapping in user mode"
+ depends on X86_64
+ depends on !PARAVIRT
+ help
+ This enforces a strict kernel and user space isolation in order to close
+ hardware side channels on kernel address information.
config SECURITYFS
bool "Enable the securityfs filesystem"
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Borislav Petkov <[email protected]>
AMD (and possibly other vendors) are not affected by the leak
KAISER is protecting against.
Keep the "nopti" for traditional reasons and add pti=<on|off|auto>
like upstream.
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/kernel-parameters.txt | 6 +++
arch/x86/mm/kaiser.c | 59 +++++++++++++++++++++++++-----------
2 files changed, 47 insertions(+), 18 deletions(-)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3327,6 +3327,12 @@ bytes respectively. Such letter suffixes
pt. [PARIDE]
See Documentation/blockdev/paride.txt.
+ pti= [X86_64]
+ Control KAISER user/kernel address space isolation:
+ on - enable
+ off - disable
+ auto - default setting
+
pty.legacy_count=
[KNL] Number of legacy pty's. Overwrites compiled-in
default number.
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -15,6 +15,7 @@
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/desc.h>
+#include <asm/cmdline.h>
int kaiser_enabled __read_mostly = 1;
EXPORT_SYMBOL(kaiser_enabled); /* for inlined TLB flush functions */
@@ -263,6 +264,43 @@ static void __init kaiser_init_all_pgds(
WARN_ON(__ret); \
} while (0)
+void __init kaiser_check_boottime_disable(void)
+{
+ bool enable = true;
+ char arg[5];
+ int ret;
+
+ ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg));
+ if (ret > 0) {
+ if (!strncmp(arg, "on", 2))
+ goto enable;
+
+ if (!strncmp(arg, "off", 3))
+ goto disable;
+
+ if (!strncmp(arg, "auto", 4))
+ goto skip;
+ }
+
+ if (cmdline_find_option_bool(boot_command_line, "nopti"))
+ goto disable;
+
+skip:
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+ goto disable;
+
+enable:
+ if (enable)
+ setup_force_cpu_cap(X86_FEATURE_KAISER);
+
+ return;
+
+disable:
+ pr_info("Kernel/User page tables isolation: disabled\n");
+ kaiser_enabled = 0;
+ setup_clear_cpu_cap(X86_FEATURE_KAISER);
+}
+
/*
* If anything in here fails, we will likely die on one of the
* first kernel->user transitions and init will die. But, we
@@ -274,12 +312,10 @@ void __init kaiser_init(void)
{
int cpu;
- if (!kaiser_enabled) {
- setup_clear_cpu_cap(X86_FEATURE_KAISER);
- return;
- }
+ kaiser_check_boottime_disable();
- setup_force_cpu_cap(X86_FEATURE_KAISER);
+ if (!kaiser_enabled)
+ return;
kaiser_init_all_pgds();
@@ -423,16 +459,3 @@ void kaiser_flush_tlb_on_return_to_user(
X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
}
EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
-
-static int __init x86_nokaiser_setup(char *s)
-{
- /* nopti doesn't accept parameters */
- if (s)
- return -EINVAL;
-
- kaiser_enabled = 0;
- pr_info("Kernel/User page tables isolation: disabled\n");
-
- return 0;
-}
-early_param("nopti", x86_nokaiser_setup);
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Added "nokaiser" boot option: an early param like "noinvpcid".
Most places now check int kaiser_enabled (#defined 0 when not
CONFIG_KAISER) instead of #ifdef CONFIG_KAISER; but entry_64.S
and entry_64_compat.S are using the ALTERNATIVE technique, which
patches in the preferred instructions at runtime. That technique
is tied to x86 cpu features, so X86_FEATURE_KAISER is fabricated.
Prior to "nokaiser", Kaiser #defined _PAGE_GLOBAL 0: revert that,
but be careful with both _PAGE_GLOBAL and CR4.PGE: setting them when
nokaiser like when !CONFIG_KAISER, but not setting either when kaiser -
neither matters on its own, but it's hard to be sure that _PAGE_GLOBAL
won't get set in some obscure corner, or something add PGE into CR4.
By omitting _PAGE_GLOBAL from __supported_pte_mask when kaiser_enabled,
all page table setup which uses pte_pfn() masks it out of the ptes.
It's slightly shameful that the same declaration versus definition of
kaiser_enabled appears in not one, not two, but in three header files
(asm/kaiser.h, asm/pgtable.h, asm/tlbflush.h). I felt safer that way,
than with #including any of those in any of the others; and did not
feel it worth an asm/kaiser_enabled.h - kernel/cpu/common.c includes
them all, so we shall hear about it if they get out of synch.
Cleanups while in the area: removed the silly #ifdef CONFIG_KAISER
from kaiser.c; removed the unused native_get_normal_pgd(); removed
the spurious reg clutter from SWITCH_*_CR3 macro stubs; corrected some
comments. But more interestingly, set CR4.PSE in secondary_startup_64:
the manual is clear that it does not matter whether it's 0 or 1 when
4-level-pts are enabled, but I was distracted to find cr4 different on
BSP and auxiliaries - BSP alone was adding PSE, in probe_page_size_mask().
Signed-off-by: Hugh Dickins <[email protected]>
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
Documentation/kernel-parameters.txt | 2 +
arch/x86/entry/entry_64.S | 15 ++++++-----
arch/x86/include/asm/cpufeatures.h | 3 ++
arch/x86/include/asm/kaiser.h | 27 +++++++++++++++------
arch/x86/include/asm/pgtable.h | 20 +++++++++++----
arch/x86/include/asm/pgtable_64.h | 13 +++-------
arch/x86/include/asm/pgtable_types.h | 4 ---
arch/x86/include/asm/tlbflush.h | 39 +++++++++++++++++++------------
arch/x86/kernel/cpu/common.c | 28 +++++++++++++++++++++-
arch/x86/kernel/espfix_64.c | 3 +-
arch/x86/kernel/head_64.S | 4 +--
arch/x86/mm/init.c | 2 -
arch/x86/mm/init_64.c | 10 +++++++
arch/x86/mm/kaiser.c | 26 +++++++++++++++++---
arch/x86/mm/pgtable.c | 8 +-----
arch/x86/mm/tlb.c | 4 ---
tools/arch/x86/include/asm/cpufeatures.h | 3 ++
17 files changed, 146 insertions(+), 65 deletions(-)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2763,6 +2763,8 @@ bytes respectively. Such letter suffixes
nojitter [IA-64] Disables jitter checking for ITC timers.
+ nokaiser [X86-64] Disable KAISER isolation of kernel from user.
+
no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver
no-kvmapf [X86,KVM] Disable paravirtualized asynchronous page
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1079,7 +1079,7 @@ ENTRY(paranoid_entry)
* unconditionally, but we need to find out whether the reverse
* should be done on return (conveyed to paranoid_exit in %ebx).
*/
- movq %cr3, %rax
+ ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
testl $KAISER_SHADOW_PGD_OFFSET, %eax
jz 2f
orl $2, %ebx
@@ -1111,6 +1111,7 @@ ENTRY(paranoid_exit)
TRACE_IRQS_OFF_DEBUG
TRACE_IRQS_IRETQ_DEBUG
#ifdef CONFIG_KAISER
+ /* No ALTERNATIVE for X86_FEATURE_KAISER: paranoid_entry sets %ebx */
testl $2, %ebx /* SWITCH_USER_CR3 needed? */
jz paranoid_exit_no_switch
SWITCH_USER_CR3
@@ -1341,13 +1342,14 @@ ENTRY(nmi)
#ifdef CONFIG_KAISER
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
- movq %cr3, %rax
+ ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
/* If PCID enabled, NOFLUSH now and NOFLUSH on return */
orq x86_cr3_pcid_noflush, %rax
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
movq %rax, %cr3
+2:
#endif
call do_nmi
@@ -1357,8 +1359,7 @@ ENTRY(nmi)
* kernel code that needs user CR3, but do we ever return
* to "user mode" where we need the kernel CR3?
*/
- popq %rax
- mov %rax, %cr3
+ ALTERNATIVE "", "popq %rax; movq %rax, %cr3", X86_FEATURE_KAISER
#endif
/*
@@ -1585,13 +1586,14 @@ end_repeat_nmi:
#ifdef CONFIG_KAISER
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
- movq %cr3, %rax
+ ALTERNATIVE "jmp 2f", "movq %cr3, %rax", X86_FEATURE_KAISER
/* If PCID enabled, NOFLUSH now and NOFLUSH on return */
orq x86_cr3_pcid_noflush, %rax
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
movq %rax, %cr3
+2:
#endif
/* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */
@@ -1603,8 +1605,7 @@ end_repeat_nmi:
* kernel code that needs user CR3, like just just before
* a sysret.
*/
- popq %rax
- mov %rax, %cr3
+ ALTERNATIVE "", "popq %rax; movq %rax, %cr3", X86_FEATURE_KAISER
#endif
testl %ebx, %ebx /* swapgs needed? */
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -198,6 +198,9 @@
#define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
+/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
+#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_KAISER w/o nokaiser */
+
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -46,28 +46,33 @@ movq \reg, %cr3
.endm
.macro SWITCH_KERNEL_CR3
-pushq %rax
+ALTERNATIVE "jmp 8f", "pushq %rax", X86_FEATURE_KAISER
_SWITCH_TO_KERNEL_CR3 %rax
popq %rax
+8:
.endm
.macro SWITCH_USER_CR3
-pushq %rax
+ALTERNATIVE "jmp 8f", "pushq %rax", X86_FEATURE_KAISER
_SWITCH_TO_USER_CR3 %rax %al
popq %rax
+8:
.endm
.macro SWITCH_KERNEL_CR3_NO_STACK
-movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
+ALTERNATIVE "jmp 8f", \
+ __stringify(movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)), \
+ X86_FEATURE_KAISER
_SWITCH_TO_KERNEL_CR3 %rax
movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
+8:
.endm
#else /* CONFIG_KAISER */
-.macro SWITCH_KERNEL_CR3 reg
+.macro SWITCH_KERNEL_CR3
.endm
-.macro SWITCH_USER_CR3 reg regb
+.macro SWITCH_USER_CR3
.endm
.macro SWITCH_KERNEL_CR3_NO_STACK
.endm
@@ -90,6 +95,16 @@ DECLARE_PER_CPU(unsigned long, x86_cr3_p
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
+extern int kaiser_enabled;
+#else
+#define kaiser_enabled 0
+#endif /* CONFIG_KAISER */
+
+/*
+ * Kaiser function prototypes are needed even when CONFIG_KAISER is not set,
+ * so as to build with tests on kaiser_enabled instead of #ifdefs.
+ */
+
/**
* kaiser_add_mapping - map a virtual memory part to the shadow (user) mapping
* @addr: the start address of the range
@@ -119,8 +134,6 @@ extern void kaiser_remove_mapping(unsign
*/
extern void kaiser_init(void);
-#endif /* CONFIG_KAISER */
-
#endif /* __ASSEMBLY */
#endif /* _ASM_X86_KAISER_H */
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -18,6 +18,12 @@
#ifndef __ASSEMBLY__
#include <asm/x86_init.h>
+#ifdef CONFIG_KAISER
+extern int kaiser_enabled;
+#else
+#define kaiser_enabled 0
+#endif
+
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd);
void ptdump_walk_pgd_level_checkwx(void);
@@ -697,7 +703,7 @@ static inline int pgd_bad(pgd_t pgd)
* page table by accident; it will fault on the first
* instruction it tries to run. See native_set_pgd().
*/
- if (IS_ENABLED(CONFIG_KAISER))
+ if (kaiser_enabled)
ignore_flags |= _PAGE_NX;
return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE;
@@ -913,12 +919,14 @@ static inline void pmdp_set_wrprotect(st
*/
static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
{
- memcpy(dst, src, count * sizeof(pgd_t));
+ memcpy(dst, src, count * sizeof(pgd_t));
#ifdef CONFIG_KAISER
- /* Clone the shadow pgd part as well */
- memcpy(native_get_shadow_pgd(dst),
- native_get_shadow_pgd(src),
- count * sizeof(pgd_t));
+ if (kaiser_enabled) {
+ /* Clone the shadow pgd part as well */
+ memcpy(native_get_shadow_pgd(dst),
+ native_get_shadow_pgd(src),
+ count * sizeof(pgd_t));
+ }
#endif
}
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -111,13 +111,12 @@ extern pgd_t kaiser_set_shadow_pgd(pgd_t
static inline pgd_t *native_get_shadow_pgd(pgd_t *pgdp)
{
+#ifdef CONFIG_DEBUG_VM
+ /* linux/mmdebug.h may not have been included at this point */
+ BUG_ON(!kaiser_enabled);
+#endif
return (pgd_t *)((unsigned long)pgdp | (unsigned long)PAGE_SIZE);
}
-
-static inline pgd_t *native_get_normal_pgd(pgd_t *pgdp)
-{
- return (pgd_t *)((unsigned long)pgdp & ~(unsigned long)PAGE_SIZE);
-}
#else
static inline pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd)
{
@@ -128,10 +127,6 @@ static inline pgd_t *native_get_shadow_p
BUILD_BUG_ON(1);
return NULL;
}
-static inline pgd_t *native_get_normal_pgd(pgd_t *pgdp)
-{
- return pgdp;
-}
#endif /* CONFIG_KAISER */
static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -45,11 +45,7 @@
#define _PAGE_ACCESSED (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
#define _PAGE_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
#define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
-#ifdef CONFIG_KAISER
-#define _PAGE_GLOBAL (_AT(pteval_t, 0))
-#else
#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
-#endif
#define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1)
#define _PAGE_SOFTW2 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW2)
#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -137,9 +137,11 @@ static inline void cr4_set_bits_and_upda
* to avoid the need for asm/kaiser.h in unexpected places.
*/
#ifdef CONFIG_KAISER
+extern int kaiser_enabled;
extern void kaiser_setup_pcid(void);
extern void kaiser_flush_tlb_on_return_to_user(void);
#else
+#define kaiser_enabled 0
static inline void kaiser_setup_pcid(void)
{
}
@@ -164,7 +166,7 @@ static inline void __native_flush_tlb(vo
* back:
*/
preempt_disable();
- if (this_cpu_has(X86_FEATURE_PCID))
+ if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID))
kaiser_flush_tlb_on_return_to_user();
native_write_cr3(native_read_cr3());
preempt_enable();
@@ -175,20 +177,30 @@ static inline void __native_flush_tlb_gl
unsigned long cr4;
cr4 = this_cpu_read(cpu_tlbstate.cr4);
- /* clear PGE */
- native_write_cr4(cr4 & ~X86_CR4_PGE);
- /* write old PGE again and flush TLBs */
- native_write_cr4(cr4);
+ if (cr4 & X86_CR4_PGE) {
+ /* clear PGE and flush TLB of all entries */
+ native_write_cr4(cr4 & ~X86_CR4_PGE);
+ /* restore PGE as it was before */
+ native_write_cr4(cr4);
+ } else {
+ /*
+ * x86_64 microcode update comes this way when CR4.PGE is not
+ * enabled, and it's safer for all callers to allow this case.
+ */
+ native_write_cr3(native_read_cr3());
+ }
}
static inline void __native_flush_tlb_global(void)
{
-#ifdef CONFIG_KAISER
- /* Globals are not used at all */
- __native_flush_tlb();
-#else
unsigned long flags;
+ if (kaiser_enabled) {
+ /* Globals are not used at all */
+ __native_flush_tlb();
+ return;
+ }
+
if (this_cpu_has(X86_FEATURE_INVPCID)) {
/*
* Using INVPCID is considerably faster than a pair of writes
@@ -208,7 +220,6 @@ static inline void __native_flush_tlb_gl
raw_local_irq_save(flags);
__native_flush_tlb_global_irq_disabled();
raw_local_irq_restore(flags);
-#endif
}
static inline void __native_flush_tlb_single(unsigned long addr)
@@ -223,7 +234,7 @@ static inline void __native_flush_tlb_si
*/
if (!this_cpu_has(X86_FEATURE_INVPCID_SINGLE)) {
- if (this_cpu_has(X86_FEATURE_PCID))
+ if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID))
kaiser_flush_tlb_on_return_to_user();
asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
return;
@@ -238,9 +249,9 @@ static inline void __native_flush_tlb_si
* Make sure to do only a single invpcid when KAISER is
* disabled and we have only a single ASID.
*/
- if (X86_CR3_PCID_ASID_KERN != X86_CR3_PCID_ASID_USER)
- invpcid_flush_one(X86_CR3_PCID_ASID_KERN, addr);
- invpcid_flush_one(X86_CR3_PCID_ASID_USER, addr);
+ if (kaiser_enabled)
+ invpcid_flush_one(X86_CR3_PCID_ASID_USER, addr);
+ invpcid_flush_one(X86_CR3_PCID_ASID_KERN, addr);
}
static inline void __flush_tlb_all(void)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -179,6 +179,20 @@ static int __init x86_pcid_setup(char *s
return 1;
}
__setup("nopcid", x86_pcid_setup);
+
+static int __init x86_nokaiser_setup(char *s)
+{
+ /* nokaiser doesn't accept parameters */
+ if (s)
+ return -EINVAL;
+#ifdef CONFIG_KAISER
+ kaiser_enabled = 0;
+ setup_clear_cpu_cap(X86_FEATURE_KAISER);
+ pr_info("nokaiser: KAISER feature disabled\n");
+#endif
+ return 0;
+}
+early_param("nokaiser", x86_nokaiser_setup);
#endif
static int __init x86_noinvpcid_setup(char *s)
@@ -327,7 +341,7 @@ static __always_inline void setup_smap(s
static void setup_pcid(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_PCID)) {
- if (cpu_has(c, X86_FEATURE_PGE)) {
+ if (cpu_has(c, X86_FEATURE_PGE) || kaiser_enabled) {
cr4_set_bits(X86_CR4_PCIDE);
/*
* INVPCID has two "groups" of types:
@@ -799,6 +813,10 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
init_scattered_cpuid_features(c);
+#ifdef CONFIG_KAISER
+ if (kaiser_enabled)
+ set_cpu_cap(c, X86_FEATURE_KAISER);
+#endif
}
static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
@@ -1537,6 +1555,14 @@ void cpu_init(void)
* try to read it.
*/
cr4_init_shadow();
+ if (!kaiser_enabled) {
+ /*
+ * secondary_startup_64() deferred setting PGE in cr4:
+ * probe_page_size_mask() sets it on the boot cpu,
+ * but it needs to be set on each secondary cpu.
+ */
+ cr4_set_bits(X86_CR4_PGE);
+ }
/*
* Load microcode on this cpu if a valid microcode is available.
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -132,9 +132,10 @@ void __init init_espfix_bsp(void)
* area to ensure it is mapped into the shadow user page
* tables.
*/
- if (IS_ENABLED(CONFIG_KAISER))
+ if (kaiser_enabled) {
set_pgd(native_get_shadow_pgd(pgd_p),
__pgd(_KERNPG_TABLE | __pa((pud_t *)espfix_pud_page)));
+ }
/* Randomize the locations */
init_espfix_random();
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -190,8 +190,8 @@ ENTRY(secondary_startup_64)
movq $(init_level4_pgt - __START_KERNEL_map), %rax
1:
- /* Enable PAE mode and PGE */
- movl $(X86_CR4_PAE | X86_CR4_PGE), %ecx
+ /* Enable PAE and PSE, but defer PGE until kaiser_enabled is decided */
+ movl $(X86_CR4_PAE | X86_CR4_PSE), %ecx
movq %rcx, %cr4
/* Setup early boot stage 4 level pagetables. */
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -177,7 +177,7 @@ static void __init probe_page_size_mask(
cr4_set_bits_and_update_boot(X86_CR4_PSE);
/* Enable PGE if available */
- if (boot_cpu_has(X86_FEATURE_PGE)) {
+ if (boot_cpu_has(X86_FEATURE_PGE) && !kaiser_enabled) {
cr4_set_bits_and_update_boot(X86_CR4_PGE);
__supported_pte_mask |= _PAGE_GLOBAL;
} else
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -324,6 +324,16 @@ void __init cleanup_highmap(void)
continue;
if (vaddr < (unsigned long) _text || vaddr > end)
set_pmd(pmd, __pmd(0));
+ else if (kaiser_enabled) {
+ /*
+ * level2_kernel_pgt is initialized with _PAGE_GLOBAL:
+ * clear that now. This is not important, so long as
+ * CR4.PGE remains clear, but it removes an anomaly.
+ * Physical mapping setup below avoids _PAGE_GLOBAL
+ * by use of massage_pgprot() inside pfn_pte() etc.
+ */
+ set_pmd(pmd, pmd_clear_flags(*pmd, _PAGE_GLOBAL));
+ }
}
}
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -16,7 +16,9 @@
#include <asm/pgalloc.h>
#include <asm/desc.h>
-#ifdef CONFIG_KAISER
+int kaiser_enabled __read_mostly = 1;
+EXPORT_SYMBOL(kaiser_enabled); /* for inlined TLB flush functions */
+
__visible
DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
@@ -167,8 +169,8 @@ static pte_t *kaiser_pagetable_walk(unsi
return pte_offset_kernel(pmd, address);
}
-int kaiser_add_user_map(const void *__start_addr, unsigned long size,
- unsigned long flags)
+static int kaiser_add_user_map(const void *__start_addr, unsigned long size,
+ unsigned long flags)
{
int ret = 0;
pte_t *pte;
@@ -177,6 +179,15 @@ int kaiser_add_user_map(const void *__st
unsigned long end_addr = PAGE_ALIGN(start_addr + size);
unsigned long target_address;
+ /*
+ * It is convenient for callers to pass in __PAGE_KERNEL etc,
+ * and there is no actual harm from setting _PAGE_GLOBAL, so
+ * long as CR4.PGE is not set. But it is nonetheless troubling
+ * to see Kaiser itself setting _PAGE_GLOBAL (now that "nokaiser"
+ * requires that not to be #defined to 0): so mask it off here.
+ */
+ flags &= ~_PAGE_GLOBAL;
+
for (; address < end_addr; address += PAGE_SIZE) {
target_address = get_pa_from_mapping(address);
if (target_address == -1) {
@@ -263,6 +274,8 @@ void __init kaiser_init(void)
{
int cpu;
+ if (!kaiser_enabled)
+ return;
kaiser_init_all_pgds();
for_each_possible_cpu(cpu) {
@@ -311,6 +324,8 @@ void __init kaiser_init(void)
/* Add a mapping to the shadow mapping, and synchronize the mappings */
int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags)
{
+ if (!kaiser_enabled)
+ return 0;
return kaiser_add_user_map((const void *)addr, size, flags);
}
@@ -322,6 +337,8 @@ void kaiser_remove_mapping(unsigned long
unsigned long addr, next;
pgd_t *pgd;
+ if (!kaiser_enabled)
+ return;
pgd = native_get_shadow_pgd(pgd_offset_k(start));
for (addr = start; addr < end; pgd++, addr = next) {
next = pgd_addr_end(addr, end);
@@ -343,6 +360,8 @@ static inline bool is_userspace_pgd(pgd_
pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp, pgd_t pgd)
{
+ if (!kaiser_enabled)
+ return pgd;
/*
* Do we need to also populate the shadow pgd? Check _PAGE_USER to
* skip cases like kexec and EFI which make temporary low mappings.
@@ -399,4 +418,3 @@ void kaiser_flush_tlb_on_return_to_user(
X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
}
EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
-#endif /* CONFIG_KAISER */
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -345,16 +345,12 @@ static inline void _pgd_free(pgd_t *pgd)
}
#else
-#ifdef CONFIG_KAISER
/*
- * Instead of one pmd, we aquire two pmds. Being order-1, it is
+ * Instead of one pgd, Kaiser acquires two pgds. Being order-1, it is
* both 8k in size and 8k-aligned. That lets us just flip bit 12
* in a pointer to swap between the two 4k halves.
*/
-#define PGD_ALLOCATION_ORDER 1
-#else
-#define PGD_ALLOCATION_ORDER 0
-#endif
+#define PGD_ALLOCATION_ORDER kaiser_enabled
static inline pgd_t *_pgd_alloc(void)
{
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -39,8 +39,7 @@ static void load_new_mm_cr3(pgd_t *pgdir
{
unsigned long new_mm_cr3 = __pa(pgdir);
-#ifdef CONFIG_KAISER
- if (this_cpu_has(X86_FEATURE_PCID)) {
+ if (kaiser_enabled && this_cpu_has(X86_FEATURE_PCID)) {
/*
* We reuse the same PCID for different tasks, so we must
* flush all the entries for the PCID out when we change tasks.
@@ -57,7 +56,6 @@ static void load_new_mm_cr3(pgd_t *pgdir
new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH;
kaiser_flush_tlb_on_return_to_user();
}
-#endif /* CONFIG_KAISER */
/*
* Caution: many callers of this function expect
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -197,6 +197,9 @@
#define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
+/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
+#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_KAISER w/o nokaiser */
+
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
An error from kaiser_add_mapping() here is not at all likely, but
Eric Biggers rightly points out that __free_ldt_struct() relies on
new_ldt->size being initialized: move that up.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/kernel/ldt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -79,11 +79,11 @@ static struct ldt_struct *alloc_ldt_stru
ret = kaiser_add_mapping((unsigned long)new_ldt->entries, alloc_size,
__PAGE_KERNEL);
+ new_ldt->size = size;
if (ret) {
__free_ldt_struct(new_ldt);
return NULL;
}
- new_ldt->size = size;
return new_ldt;
}
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Mostly this commit is just unshouting X86_CR3_PCID_KERN_VAR and
X86_CR3_PCID_USER_VAR: we usually name variables in lower-case.
But why does x86_cr3_pcid_noflush need to be __aligned(PAGE_SIZE)?
Ah, it's a leftover from when kaiser_add_user_map() once complained
about mapping the same page twice. Make it __read_mostly instead.
(I'm a little uneasy about all the unrelated data which shares its
page getting user-mapped too, but that was so before, and not a big
deal: though we call it user-mapped, it's not mapped with _PAGE_USER.)
And there is a little change around the two calls to do_nmi().
Previously they set the NOFLUSH bit (if PCID supported) when
forcing to kernel context before do_nmi(); now they also have the
NOFLUSH bit set (if PCID supported) when restoring context after:
nothing done in do_nmi() should require a TLB to be flushed here.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 8 ++++----
arch/x86/include/asm/kaiser.h | 11 +++++------
arch/x86/mm/kaiser.c | 13 +++++++------
3 files changed, 16 insertions(+), 16 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1316,11 +1316,11 @@ ENTRY(nmi)
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
+ /* If PCID enabled, NOFLUSH now and NOFLUSH on return */
+ orq x86_cr3_pcid_noflush, %rax
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
- /* Add back kernel PCID and "no flush" bit */
- orq X86_CR3_PCID_KERN_VAR, %rax
movq %rax, %cr3
#endif
call do_nmi
@@ -1560,11 +1560,11 @@ end_repeat_nmi:
/* Unconditionally use kernel CR3 for do_nmi() */
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
+ /* If PCID enabled, NOFLUSH now and NOFLUSH on return */
+ orq x86_cr3_pcid_noflush, %rax
pushq %rax
/* mask off "user" bit of pgd address and 12 PCID bits: */
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
- /* Add back kernel PCID and "no flush" bit */
- orq X86_CR3_PCID_KERN_VAR, %rax
movq %rax, %cr3
#endif
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -25,7 +25,7 @@
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
-orq X86_CR3_PCID_KERN_VAR, \reg
+orq x86_cr3_pcid_noflush, \reg
movq \reg, %cr3
.endm
@@ -37,11 +37,10 @@ movq \reg, %cr3
* not enabled): so that the one register can update both memory and cr3.
*/
movq %cr3, \reg
-andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
-orq PER_CPU_VAR(X86_CR3_PCID_USER_VAR), \reg
+orq PER_CPU_VAR(x86_cr3_pcid_user), \reg
js 9f
/* FLUSH this time, reset to NOFLUSH for next time (if PCID enabled) */
-movb \regb, PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
+movb \regb, PER_CPU_VAR(x86_cr3_pcid_user+7)
9:
movq \reg, %cr3
.endm
@@ -94,8 +93,8 @@ movq PER_CPU_VAR(unsafe_stack_register_b
*/
DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
-extern unsigned long X86_CR3_PCID_KERN_VAR;
-DECLARE_PER_CPU(unsigned long, X86_CR3_PCID_USER_VAR);
+extern unsigned long x86_cr3_pcid_noflush;
+DECLARE_PER_CPU(unsigned long, x86_cr3_pcid_user);
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -28,8 +28,8 @@ DEFINE_PER_CPU_USER_MAPPED(unsigned long
* This is also handy because systems that do not support PCIDs
* just end up or'ing a 0 into their CR3, which does no harm.
*/
-__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_KERN_VAR;
-DEFINE_PER_CPU(unsigned long, X86_CR3_PCID_USER_VAR);
+unsigned long x86_cr3_pcid_noflush __read_mostly;
+DEFINE_PER_CPU(unsigned long, x86_cr3_pcid_user);
/*
* At runtime, the only things we map are some things for CPU
@@ -303,7 +303,8 @@ void __init kaiser_init(void)
sizeof(gate_desc) * NR_VECTORS,
__PAGE_KERNEL);
- kaiser_add_user_map_early(&X86_CR3_PCID_KERN_VAR, PAGE_SIZE,
+ kaiser_add_user_map_early(&x86_cr3_pcid_noflush,
+ sizeof(x86_cr3_pcid_noflush),
__PAGE_KERNEL);
}
@@ -381,8 +382,8 @@ void kaiser_setup_pcid(void)
* These variables are used by the entry/exit
* code to change PCID and pgd and TLB flushing.
*/
- X86_CR3_PCID_KERN_VAR = kern_cr3;
- this_cpu_write(X86_CR3_PCID_USER_VAR, user_cr3);
+ x86_cr3_pcid_noflush = kern_cr3;
+ this_cpu_write(x86_cr3_pcid_user, user_cr3);
}
/*
@@ -392,7 +393,7 @@ void kaiser_setup_pcid(void)
*/
void kaiser_flush_tlb_on_return_to_user(void)
{
- this_cpu_write(X86_CR3_PCID_USER_VAR,
+ this_cpu_write(x86_cr3_pcid_user,
X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
}
EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Why was 4 chosen for kernel PCID and 6 for user PCID?
No good reason in a backport where PCIDs are only used for Kaiser.
If we continue with those, then we shall need to add Andy Lutomirski's
4.13 commit 6c690ee1039b ("x86/mm: Split read_cr3() into read_cr3_pa()
and __read_cr3()"), which deals with the problem of read_cr3() callers
finding stray bits in the cr3 that they expected to be page-aligned;
and for hibernation, his 4.14 commit f34902c5c6c0 ("x86/hibernate/64:
Mask off CR3's PCID bits in the saved CR3").
But if 0 is used for kernel PCID, then there's no need to add in those
commits - whenever the kernel looks, it sees 0 in the lower bits; and
0 for kernel seems an obvious choice.
And I naughtily propose 128 for user PCID. Because there's a place
in _SWITCH_TO_USER_CR3 where it takes note of the need for TLB FLUSH,
but needs to reset that to NOFLUSH for the next occasion. Currently
it does so with a "movb $(0x80)" into the high byte of the per-cpu
quadword, but that will cause a machine without PCID support to crash.
Now, if %al just happened to have 0x80 in it at that point, on a
machine with PCID support, but 0 on a machine without PCID support...
(That will go badly wrong once the pgd can be at a physical address
above 2^56, but even with 5-level paging, physical goes up to 2^52.)
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/kaiser.h | 19 ++++++++++++-------
arch/x86/include/asm/pgtable_types.h | 7 ++++---
arch/x86/mm/tlb.c | 3 +++
3 files changed, 19 insertions(+), 10 deletions(-)
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -29,14 +29,19 @@ orq X86_CR3_PCID_KERN_VAR, \reg
movq \reg, %cr3
.endm
-.macro _SWITCH_TO_USER_CR3 reg
+.macro _SWITCH_TO_USER_CR3 reg regb
+/*
+ * regb must be the low byte portion of reg: because we have arranged
+ * for the low byte of the user PCID to serve as the high byte of NOFLUSH
+ * (0x80 for each when PCID is enabled, or 0x00 when PCID and NOFLUSH are
+ * not enabled): so that the one register can update both memory and cr3.
+ */
movq %cr3, \reg
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
orq PER_CPU_VAR(X86_CR3_PCID_USER_VAR), \reg
js 9f
-// FLUSH this time, reset to NOFLUSH for next time
-// But if nopcid? Consider using 0x80 for user pcid?
-movb $(0x80), PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
+/* FLUSH this time, reset to NOFLUSH for next time (if PCID enabled) */
+movb \regb, PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
9:
movq \reg, %cr3
.endm
@@ -49,7 +54,7 @@ popq %rax
.macro SWITCH_USER_CR3
pushq %rax
-_SWITCH_TO_USER_CR3 %rax
+_SWITCH_TO_USER_CR3 %rax %al
popq %rax
.endm
@@ -61,7 +66,7 @@ movq PER_CPU_VAR(unsafe_stack_register_b
.macro SWITCH_USER_CR3_NO_STACK
movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
-_SWITCH_TO_USER_CR3 %rax
+_SWITCH_TO_USER_CR3 %rax %al
movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
.endm
@@ -69,7 +74,7 @@ movq PER_CPU_VAR(unsafe_stack_register_b
.macro SWITCH_KERNEL_CR3 reg
.endm
-.macro SWITCH_USER_CR3 reg
+.macro SWITCH_USER_CR3 reg regb
.endm
.macro SWITCH_USER_CR3_NO_STACK
.endm
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -146,16 +146,17 @@
/* Mask for all the PCID-related bits in CR3: */
#define X86_CR3_PCID_MASK (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_MASK)
+#define X86_CR3_PCID_ASID_KERN (_AC(0x0,UL))
+
#if defined(CONFIG_KAISER) && defined(CONFIG_X86_64)
-#define X86_CR3_PCID_ASID_KERN (_AC(0x4,UL))
-#define X86_CR3_PCID_ASID_USER (_AC(0x6,UL))
+/* Let X86_CR3_PCID_ASID_USER be usable for the X86_CR3_PCID_NOFLUSH bit */
+#define X86_CR3_PCID_ASID_USER (_AC(0x80,UL))
#define X86_CR3_PCID_KERN_FLUSH (X86_CR3_PCID_ASID_KERN)
#define X86_CR3_PCID_USER_FLUSH (X86_CR3_PCID_ASID_USER)
#define X86_CR3_PCID_KERN_NOFLUSH (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_KERN)
#define X86_CR3_PCID_USER_NOFLUSH (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_USER)
#else
-#define X86_CR3_PCID_ASID_KERN (_AC(0x0,UL))
#define X86_CR3_PCID_ASID_USER (_AC(0x0,UL))
/*
* PCIDs are unsupported on 32-bit and none of these bits can be
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -50,6 +50,9 @@ static void load_new_mm_cr3(pgd_t *pgdir
* invpcid_flush_single_context(X86_CR3_PCID_ASID_USER) could
* do it here, but can only be used if X86_FEATURE_INVPCID is
* available - and many machines support pcid without invpcid.
+ *
+ * The line below is a no-op: X86_CR3_PCID_KERN_FLUSH is now 0;
+ * but keep that line in there in case something changes.
*/
new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH;
kaiser_flush_tlb_on_return_to_user();
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
We have many machines (Westmere, Sandybridge, Ivybridge) supporting
PCID but not INVPCID: on these load_new_mm_cr3() simply crashed.
Flushing user context inside load_new_mm_cr3() without the use of
invpcid is difficult: momentarily switch from kernel to user context
and back to do so? I'm not sure whether that can be safely done at
all, and would risk polluting user context with kernel internals,
and kernel context with stale user externals.
Instead, follow the hint in the comment that was there: change
X86_CR3_PCID_USER_VAR to be a per-cpu variable, then load_new_mm_cr3()
can leave a note in it, for SWITCH_USER_CR3 on return to userspace to
flush user context TLB, instead of default X86_CR3_PCID_USER_NOFLUSH.
Which works well enough that there's no need to do it this way only
when invpcid is unsupported: it's a good alternative to invpcid here.
But there's a couple of inlines in asm/tlbflush.h that need to do the
same trick, so it's best to localize all this per-cpu business in
mm/kaiser.c: moving that part of the initialization from setup_pcid()
to kaiser_setup_pcid(); with kaiser_flush_tlb_on_return_to_user() the
function for noting an X86_CR3_PCID_USER_FLUSH. And let's keep a
KAISER_SHADOW_PGD_OFFSET in there, to avoid the extra OR on exit.
I did try to make the feature tests in asm/tlbflush.h more consistent
with each other: there seem to be far too many ways of performing such
tests, and I don't have a good grasp of their differences. At first
I converted them all to be static_cpu_has(): but that proved to be a
mistake, as the comment in __native_flush_tlb_single() hints; so then
I reversed and made them all this_cpu_has(). Probably all gratuitous
change, but that's the way it's working at present.
I am slightly bothered by the way non-per-cpu X86_CR3_PCID_KERN_VAR
gets re-initialized by each cpu (before and after these changes):
no problem when (as usual) all cpus on a machine have the same
features, but in principle incorrect. However, my experiment
to per-cpu-ify that one did not end well...
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/kaiser.h | 18 +++++++-----
arch/x86/include/asm/tlbflush.h | 56 +++++++++++++++++++++++++++-------------
arch/x86/kernel/cpu/common.c | 22 ---------------
arch/x86/mm/kaiser.c | 50 +++++++++++++++++++++++++++++++----
arch/x86/mm/tlb.c | 46 ++++++++++++--------------------
5 files changed, 113 insertions(+), 79 deletions(-)
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -32,13 +32,12 @@ movq \reg, %cr3
.macro _SWITCH_TO_USER_CR3 reg
movq %cr3, \reg
andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
-/*
- * This can obviously be one instruction by putting the
- * KAISER_SHADOW_PGD_OFFSET bit in the X86_CR3_PCID_USER_VAR.
- * But, just leave it now for simplicity.
- */
-orq X86_CR3_PCID_USER_VAR, \reg
-orq $(KAISER_SHADOW_PGD_OFFSET), \reg
+orq PER_CPU_VAR(X86_CR3_PCID_USER_VAR), \reg
+js 9f
+// FLUSH this time, reset to NOFLUSH for next time
+// But if nopcid? Consider using 0x80 for user pcid?
+movb $(0x80), PER_CPU_VAR(X86_CR3_PCID_USER_VAR+7)
+9:
movq \reg, %cr3
.endm
@@ -90,6 +89,11 @@ movq PER_CPU_VAR(unsafe_stack_register_b
*/
DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+extern unsigned long X86_CR3_PCID_KERN_VAR;
+DECLARE_PER_CPU(unsigned long, X86_CR3_PCID_USER_VAR);
+
+extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
+
/**
* kaiser_add_mapping - map a virtual memory part to the shadow (user) mapping
* @addr: the start address of the range
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -13,6 +13,7 @@ static inline void __invpcid(unsigned lo
unsigned long type)
{
struct { u64 d[2]; } desc = { { pcid, addr } };
+
/*
* The memory clobber is because the whole point is to invalidate
* stale TLB entries and, especially if we're flushing global
@@ -131,27 +132,42 @@ static inline void cr4_set_bits_and_upda
cr4_set_bits(mask);
}
+/*
+ * Declare a couple of kaiser interfaces here for convenience,
+ * to avoid the need for asm/kaiser.h in unexpected places.
+ */
+#ifdef CONFIG_KAISER
+extern void kaiser_setup_pcid(void);
+extern void kaiser_flush_tlb_on_return_to_user(void);
+#else
+static inline void kaiser_setup_pcid(void)
+{
+}
+static inline void kaiser_flush_tlb_on_return_to_user(void)
+{
+}
+#endif
+
static inline void __native_flush_tlb(void)
{
- if (!cpu_feature_enabled(X86_FEATURE_INVPCID)) {
+ if (this_cpu_has(X86_FEATURE_INVPCID)) {
/*
- * If current->mm == NULL then we borrow a mm which may change during a
- * task switch and therefore we must not be preempted while we write CR3
- * back:
+ * Note, this works with CR4.PCIDE=0 or 1.
*/
- preempt_disable();
- native_write_cr3(native_read_cr3());
- preempt_enable();
+ invpcid_flush_all_nonglobals();
return;
}
+
/*
- * We are no longer using globals with KAISER, so a
- * "nonglobals" flush would work too. But, this is more
- * conservative.
- *
- * Note, this works with CR4.PCIDE=0 or 1.
+ * If current->mm == NULL then we borrow a mm which may change during a
+ * task switch and therefore we must not be preempted while we write CR3
+ * back:
*/
- invpcid_flush_all();
+ preempt_disable();
+ if (this_cpu_has(X86_FEATURE_PCID))
+ kaiser_flush_tlb_on_return_to_user();
+ native_write_cr3(native_read_cr3());
+ preempt_enable();
}
static inline void __native_flush_tlb_global_irq_disabled(void)
@@ -167,9 +183,13 @@ static inline void __native_flush_tlb_gl
static inline void __native_flush_tlb_global(void)
{
+#ifdef CONFIG_KAISER
+ /* Globals are not used at all */
+ __native_flush_tlb();
+#else
unsigned long flags;
- if (static_cpu_has(X86_FEATURE_INVPCID)) {
+ if (this_cpu_has(X86_FEATURE_INVPCID)) {
/*
* Using INVPCID is considerably faster than a pair of writes
* to CR4 sandwiched inside an IRQ flag save/restore.
@@ -186,10 +206,9 @@ static inline void __native_flush_tlb_gl
* be called from deep inside debugging code.)
*/
raw_local_irq_save(flags);
-
__native_flush_tlb_global_irq_disabled();
-
raw_local_irq_restore(flags);
+#endif
}
static inline void __native_flush_tlb_single(unsigned long addr)
@@ -200,9 +219,12 @@ static inline void __native_flush_tlb_si
*
* The ASIDs used below are hard-coded. But, we must not
* call invpcid(type=1/2) before CR4.PCIDE=1. Just call
- * invpcid in the case we are called early.
+ * invlpg in the case we are called early.
*/
+
if (!this_cpu_has(X86_FEATURE_INVPCID_SINGLE)) {
+ if (this_cpu_has(X86_FEATURE_PCID))
+ kaiser_flush_tlb_on_return_to_user();
asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
return;
}
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -324,33 +324,12 @@ static __always_inline void setup_smap(s
}
}
-/*
- * These can have bit 63 set, so we can not just use a plain "or"
- * instruction to get their value or'd into CR3. It would take
- * another register. So, we use a memory reference to these
- * instead.
- *
- * This is also handy because systems that do not support
- * PCIDs just end up or'ing a 0 into their CR3, which does
- * no harm.
- */
-__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_KERN_VAR = 0;
-__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_USER_VAR = 0;
-
static void setup_pcid(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_PCID)) {
if (cpu_has(c, X86_FEATURE_PGE)) {
cr4_set_bits(X86_CR4_PCIDE);
/*
- * These variables are used by the entry/exit
- * code to change PCIDs.
- */
-#ifdef CONFIG_KAISER
- X86_CR3_PCID_KERN_VAR = X86_CR3_PCID_KERN_NOFLUSH;
- X86_CR3_PCID_USER_VAR = X86_CR3_PCID_USER_NOFLUSH;
-#endif
- /*
* INVPCID has two "groups" of types:
* 1/2: Invalidate an individual address
* 3/4: Invalidate all contexts
@@ -375,6 +354,7 @@ static void setup_pcid(struct cpuinfo_x8
clear_cpu_cap(c, X86_FEATURE_PCID);
}
}
+ kaiser_setup_pcid();
}
/*
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -11,12 +11,26 @@
#include <linux/uaccess.h>
#include <asm/kaiser.h>
+#include <asm/tlbflush.h> /* to verify its kaiser declarations */
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/desc.h>
+
#ifdef CONFIG_KAISER
+__visible
+DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
+
+/*
+ * These can have bit 63 set, so we can not just use a plain "or"
+ * instruction to get their value or'd into CR3. It would take
+ * another register. So, we use a memory reference to these instead.
+ *
+ * This is also handy because systems that do not support PCIDs
+ * just end up or'ing a 0 into their CR3, which does no harm.
+ */
+__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_KERN_VAR;
+DEFINE_PER_CPU(unsigned long, X86_CR3_PCID_USER_VAR);
-__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
/*
* At runtime, the only things we map are some things for CPU
* hotplug, and stacks for new processes. No two CPUs will ever
@@ -238,9 +252,6 @@ static void __init kaiser_init_all_pgds(
WARN_ON(__ret); \
} while (0)
-extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
-extern unsigned long X86_CR3_PCID_KERN_VAR;
-extern unsigned long X86_CR3_PCID_USER_VAR;
/*
* If anything in here fails, we will likely die on one of the
* first kernel->user transitions and init will die. But, we
@@ -294,8 +305,6 @@ void __init kaiser_init(void)
kaiser_add_user_map_early(&X86_CR3_PCID_KERN_VAR, PAGE_SIZE,
__PAGE_KERNEL);
- kaiser_add_user_map_early(&X86_CR3_PCID_USER_VAR, PAGE_SIZE,
- __PAGE_KERNEL);
}
/* Add a mapping to the shadow mapping, and synchronize the mappings */
@@ -358,4 +367,33 @@ pgd_t kaiser_set_shadow_pgd(pgd_t *pgdp,
}
return pgd;
}
+
+void kaiser_setup_pcid(void)
+{
+ unsigned long kern_cr3 = 0;
+ unsigned long user_cr3 = KAISER_SHADOW_PGD_OFFSET;
+
+ if (this_cpu_has(X86_FEATURE_PCID)) {
+ kern_cr3 |= X86_CR3_PCID_KERN_NOFLUSH;
+ user_cr3 |= X86_CR3_PCID_USER_NOFLUSH;
+ }
+ /*
+ * These variables are used by the entry/exit
+ * code to change PCID and pgd and TLB flushing.
+ */
+ X86_CR3_PCID_KERN_VAR = kern_cr3;
+ this_cpu_write(X86_CR3_PCID_USER_VAR, user_cr3);
+}
+
+/*
+ * Make a note that this cpu will need to flush USER tlb on return to user.
+ * Caller checks whether this_cpu_has(X86_FEATURE_PCID) before calling:
+ * if cpu does not, then the NOFLUSH bit will never have been set.
+ */
+void kaiser_flush_tlb_on_return_to_user(void)
+{
+ this_cpu_write(X86_CR3_PCID_USER_VAR,
+ X86_CR3_PCID_USER_FLUSH | KAISER_SHADOW_PGD_OFFSET);
+}
+EXPORT_SYMBOL(kaiser_flush_tlb_on_return_to_user);
#endif /* CONFIG_KAISER */
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -6,13 +6,14 @@
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/cpu.h>
+#include <linux/debugfs.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/cache.h>
#include <asm/apic.h>
#include <asm/uv/uv.h>
-#include <linux/debugfs.h>
+#include <asm/kaiser.h>
/*
* TLB flushing, formerly SMP-only
@@ -38,34 +39,23 @@ static void load_new_mm_cr3(pgd_t *pgdir
{
unsigned long new_mm_cr3 = __pa(pgdir);
- /*
- * KAISER, plus PCIDs needs some extra work here. But,
- * if either of features is not present, we need no
- * PCIDs here and just do a normal, full TLB flush with
- * the write_cr3()
- */
- if (!IS_ENABLED(CONFIG_KAISER) ||
- !cpu_feature_enabled(X86_FEATURE_PCID))
- goto out_set_cr3;
- /*
- * We reuse the same PCID for different tasks, so we must
- * flush all the entires for the PCID out when we change
- * tasks.
- */
- new_mm_cr3 = X86_CR3_PCID_KERN_FLUSH | __pa(pgdir);
-
- /*
- * The flush from load_cr3() may leave old TLB entries
- * for userspace in place. We must flush that context
- * separately. We can theoretically delay doing this
- * until we actually load up the userspace CR3, but
- * that's a bit tricky. We have to have the "need to
- * flush userspace PCID" bit per-cpu and check it in the
- * exit-to-userspace paths.
- */
- invpcid_flush_single_context(X86_CR3_PCID_ASID_USER);
+#ifdef CONFIG_KAISER
+ if (this_cpu_has(X86_FEATURE_PCID)) {
+ /*
+ * We reuse the same PCID for different tasks, so we must
+ * flush all the entries for the PCID out when we change tasks.
+ * Flush KERN below, flush USER when returning to userspace in
+ * kaiser's SWITCH_USER_CR3 (_SWITCH_TO_USER_CR3) macro.
+ *
+ * invpcid_flush_single_context(X86_CR3_PCID_ASID_USER) could
+ * do it here, but can only be used if X86_FEATURE_INVPCID is
+ * available - and many machines support pcid without invpcid.
+ */
+ new_mm_cr3 |= X86_CR3_PCID_KERN_FLUSH;
+ kaiser_flush_tlb_on_return_to_user();
+ }
+#endif /* CONFIG_KAISER */
-out_set_cr3:
/*
* Caution: many callers of this function expect
* that load_cr3() is serializing and orders TLB
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
The kaiser update made an interesting choice, never to free any shadow
page tables. Contention on global spinlock was worrying, particularly
with it held across page table scans when freeing. Something had to be
done: I was going to add refcounting; but simply never to free them is
an appealing choice, minimizing contention without complicating the code
(the more a page table is found already, the less the spinlock is used).
But leaking pages in this way is also a worry: can we get away with it?
At the very least, we need a count to show how bad it actually gets:
in principle, one might end up wasting about 1/256 of memory that way
(1/512 for when direct-mapped pages have to be user-mapped, plus 1/512
for when they are user-mapped from the vmalloc area on another occasion
(but we don't have vmalloc'ed stacks, so only large ldts are vmalloc'ed).
Add per-cpu stat NR_KAISERTABLE: including 256 at startup for the
shared pgd entries, and 1 for each intermediate page table added
thereafter for user-mapping - but leave out the 1 per mm, for its
shadow pgd, because that distracts from the monotonic increase.
Shown in /proc/vmstat as nr_overhead (0 if kaiser not enabled).
In practice, it doesn't look so bad so far: more like 1/12000 after
nine hours of gtests below; and movable pageblock segregation should
tend to cluster the kaiser tables into a subset of the address space
(if not, they will be bad for compaction too). But production may
tell a different story: keep an eye on this number, and bring back
lighter freeing if it gets out of control (maybe a shrinker).
["nr_overhead" should of course say "nr_kaisertable", if it needs
to stay; but for the moment we are being coy, preferring that when
Joe Blow notices a new line in his /proc/vmstat, he does not get
too curious about what this "kaiser" stuff might be.]
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 16 +++++++++++-----
include/linux/mmzone.h | 3 ++-
mm/vmstat.c | 1 +
3 files changed, 14 insertions(+), 6 deletions(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -121,9 +121,11 @@ static pte_t *kaiser_pagetable_walk(unsi
if (!new_pmd_page)
return NULL;
spin_lock(&shadow_table_allocation_lock);
- if (pud_none(*pud))
+ if (pud_none(*pud)) {
set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
- else
+ __inc_zone_page_state(virt_to_page((void *)
+ new_pmd_page), NR_KAISERTABLE);
+ } else
free_page(new_pmd_page);
spin_unlock(&shadow_table_allocation_lock);
}
@@ -139,9 +141,11 @@ static pte_t *kaiser_pagetable_walk(unsi
if (!new_pte_page)
return NULL;
spin_lock(&shadow_table_allocation_lock);
- if (pmd_none(*pmd))
+ if (pmd_none(*pmd)) {
set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page)));
- else
+ __inc_zone_page_state(virt_to_page((void *)
+ new_pte_page), NR_KAISERTABLE);
+ } else
free_page(new_pte_page);
spin_unlock(&shadow_table_allocation_lock);
}
@@ -205,11 +209,13 @@ static void __init kaiser_init_all_pgds(
pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0));
for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) {
pgd_t new_pgd;
- pud_t *pud = pud_alloc_one(&init_mm, PAGE_OFFSET + i * PGDIR_SIZE);
+ pud_t *pud = pud_alloc_one(&init_mm,
+ PAGE_OFFSET + i * PGDIR_SIZE);
if (!pud) {
WARN_ON(1);
break;
}
+ inc_zone_page_state(virt_to_page(pud), NR_KAISERTABLE);
new_pgd = __pgd(_KERNPG_TABLE |__pa(pud));
/*
* Make sure not to stomp on some other pgd entry.
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -124,8 +124,9 @@ enum zone_stat_item {
NR_SLAB_UNRECLAIMABLE,
NR_PAGETABLE, /* used for pagetables */
NR_KERNEL_STACK_KB, /* measured in KiB */
- /* Second 128 byte cacheline */
+ NR_KAISERTABLE,
NR_BOUNCE,
+ /* Second 128 byte cacheline */
#if IS_ENABLED(CONFIG_ZSMALLOC)
NR_ZSPAGES, /* allocated in zsmalloc */
#endif
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -932,6 +932,7 @@ const char * const vmstat_text[] = {
"nr_slab_unreclaimable",
"nr_page_table_pages",
"nr_kernel_stack",
+ "nr_overhead",
"nr_bounce",
#if IS_ENABLED(CONFIG_ZSMALLOC)
"nr_zspages",
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Merged performance improvements to Kaiser, using distinct kernel
and user Process Context Identifiers to minimize the TLB flushing.
[This work actually all from Dave Hansen 2017-08-30:
still omitting trackswitch mods, and KAISER_REAL_SWITCH deleted.]
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 10 ++++-
arch/x86/entry/entry_64_compat.S | 1
arch/x86/include/asm/cpufeatures.h | 1
arch/x86/include/asm/kaiser.h | 15 ++++++-
arch/x86/include/asm/pgtable_types.h | 26 +++++++++++++
arch/x86/include/asm/tlbflush.h | 54 +++++++++++++++++++++++-----
arch/x86/include/uapi/asm/processor-flags.h | 3 +
arch/x86/kernel/cpu/common.c | 34 +++++++++++++++++
arch/x86/kvm/x86.c | 3 +
arch/x86/mm/kaiser.c | 7 +++
arch/x86/mm/tlb.c | 46 ++++++++++++++++++++++-
11 files changed, 182 insertions(+), 18 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1317,7 +1317,10 @@ ENTRY(nmi)
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
pushq %rax
- andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
+ /* mask off "user" bit of pgd address and 12 PCID bits: */
+ andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
+ /* Add back kernel PCID and "no flush" bit */
+ orq X86_CR3_PCID_KERN_VAR, %rax
movq %rax, %cr3
#endif
call do_nmi
@@ -1558,7 +1561,10 @@ end_repeat_nmi:
/* %rax is saved above, so OK to clobber here */
movq %cr3, %rax
pushq %rax
- andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
+ /* mask off "user" bit of pgd address and 12 PCID bits: */
+ andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), %rax
+ /* Add back kernel PCID and "no flush" bit */
+ orq X86_CR3_PCID_KERN_VAR, %rax
movq %rax, %cr3
#endif
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -13,6 +13,7 @@
#include <asm/irqflags.h>
#include <asm/asm.h>
#include <asm/smap.h>
+#include <asm/pgtable_types.h>
#include <asm/kaiser.h>
#include <linux/linkage.h>
#include <linux/err.h>
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -189,6 +189,7 @@
#define X86_FEATURE_CPB ( 7*32+ 2) /* AMD Core Performance Boost */
#define X86_FEATURE_EPB ( 7*32+ 3) /* IA32_ENERGY_PERF_BIAS support */
+#define X86_FEATURE_INVPCID_SINGLE ( 7*32+ 4) /* Effectively INVPCID && CR4.PCIDE=1 */
#define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -1,5 +1,8 @@
#ifndef _ASM_X86_KAISER_H
#define _ASM_X86_KAISER_H
+
+#include <uapi/asm/processor-flags.h> /* For PCID constants */
+
/*
* This file includes the definitions for the KAISER feature.
* KAISER is a counter measure against x86_64 side channel attacks on
@@ -21,13 +24,21 @@
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
-andq $(~KAISER_SHADOW_PGD_OFFSET), \reg
+andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
+orq X86_CR3_PCID_KERN_VAR, \reg
movq \reg, %cr3
.endm
.macro _SWITCH_TO_USER_CR3 reg
movq %cr3, \reg
-orq $(KAISER_SHADOW_PGD_OFFSET), \reg
+andq $(~(X86_CR3_PCID_ASID_MASK | KAISER_SHADOW_PGD_OFFSET)), \reg
+/*
+ * This can obviously be one instruction by putting the
+ * KAISER_SHADOW_PGD_OFFSET bit in the X86_CR3_PCID_USER_VAR.
+ * But, just leave it now for simplicity.
+ */
+orq X86_CR3_PCID_USER_VAR, \reg
+orq $(KAISER_SHADOW_PGD_OFFSET), \reg
movq \reg, %cr3
.endm
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -141,6 +141,32 @@
_PAGE_SOFT_DIRTY)
#define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
+/* The ASID is the lower 12 bits of CR3 */
+#define X86_CR3_PCID_ASID_MASK (_AC((1<<12)-1,UL))
+
+/* Mask for all the PCID-related bits in CR3: */
+#define X86_CR3_PCID_MASK (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_MASK)
+#if defined(CONFIG_KAISER) && defined(CONFIG_X86_64)
+#define X86_CR3_PCID_ASID_KERN (_AC(0x4,UL))
+#define X86_CR3_PCID_ASID_USER (_AC(0x6,UL))
+
+#define X86_CR3_PCID_KERN_FLUSH (X86_CR3_PCID_ASID_KERN)
+#define X86_CR3_PCID_USER_FLUSH (X86_CR3_PCID_ASID_USER)
+#define X86_CR3_PCID_KERN_NOFLUSH (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_KERN)
+#define X86_CR3_PCID_USER_NOFLUSH (X86_CR3_PCID_NOFLUSH | X86_CR3_PCID_ASID_USER)
+#else
+#define X86_CR3_PCID_ASID_KERN (_AC(0x0,UL))
+#define X86_CR3_PCID_ASID_USER (_AC(0x0,UL))
+/*
+ * PCIDs are unsupported on 32-bit and none of these bits can be
+ * set in CR3:
+ */
+#define X86_CR3_PCID_KERN_FLUSH (0)
+#define X86_CR3_PCID_USER_FLUSH (0)
+#define X86_CR3_PCID_KERN_NOFLUSH (0)
+#define X86_CR3_PCID_USER_NOFLUSH (0)
+#endif
+
/*
* The cache modes defined here are used to translate between pure SW usage
* and the HW defined cache mode bits and/or PAT entries.
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -13,7 +13,6 @@ static inline void __invpcid(unsigned lo
unsigned long type)
{
struct { u64 d[2]; } desc = { { pcid, addr } };
-
/*
* The memory clobber is because the whole point is to invalidate
* stale TLB entries and, especially if we're flushing global
@@ -134,14 +133,25 @@ static inline void cr4_set_bits_and_upda
static inline void __native_flush_tlb(void)
{
+ if (!cpu_feature_enabled(X86_FEATURE_INVPCID)) {
+ /*
+ * If current->mm == NULL then we borrow a mm which may change during a
+ * task switch and therefore we must not be preempted while we write CR3
+ * back:
+ */
+ preempt_disable();
+ native_write_cr3(native_read_cr3());
+ preempt_enable();
+ return;
+ }
/*
- * If current->mm == NULL then we borrow a mm which may change during a
- * task switch and therefore we must not be preempted while we write CR3
- * back:
- */
- preempt_disable();
- native_write_cr3(native_read_cr3());
- preempt_enable();
+ * We are no longer using globals with KAISER, so a
+ * "nonglobals" flush would work too. But, this is more
+ * conservative.
+ *
+ * Note, this works with CR4.PCIDE=0 or 1.
+ */
+ invpcid_flush_all();
}
static inline void __native_flush_tlb_global_irq_disabled(void)
@@ -163,6 +173,8 @@ static inline void __native_flush_tlb_gl
/*
* Using INVPCID is considerably faster than a pair of writes
* to CR4 sandwiched inside an IRQ flag save/restore.
+ *
+ * Note, this works with CR4.PCIDE=0 or 1.
*/
invpcid_flush_all();
return;
@@ -182,7 +194,31 @@ static inline void __native_flush_tlb_gl
static inline void __native_flush_tlb_single(unsigned long addr)
{
- asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
+ /*
+ * SIMICS #GP's if you run INVPCID with type 2/3
+ * and X86_CR4_PCIDE clear. Shame!
+ *
+ * The ASIDs used below are hard-coded. But, we must not
+ * call invpcid(type=1/2) before CR4.PCIDE=1. Just call
+ * invpcid in the case we are called early.
+ */
+ if (!this_cpu_has(X86_FEATURE_INVPCID_SINGLE)) {
+ asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
+ return;
+ }
+ /* Flush the address out of both PCIDs. */
+ /*
+ * An optimization here might be to determine addresses
+ * that are only kernel-mapped and only flush the kernel
+ * ASID. But, userspace flushes are probably much more
+ * important performance-wise.
+ *
+ * Make sure to do only a single invpcid when KAISER is
+ * disabled and we have only a single ASID.
+ */
+ if (X86_CR3_PCID_ASID_KERN != X86_CR3_PCID_ASID_USER)
+ invpcid_flush_one(X86_CR3_PCID_ASID_KERN, addr);
+ invpcid_flush_one(X86_CR3_PCID_ASID_USER, addr);
}
static inline void __flush_tlb_all(void)
--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -77,7 +77,8 @@
#define X86_CR3_PWT _BITUL(X86_CR3_PWT_BIT)
#define X86_CR3_PCD_BIT 4 /* Page Cache Disable */
#define X86_CR3_PCD _BITUL(X86_CR3_PCD_BIT)
-#define X86_CR3_PCID_MASK _AC(0x00000fff,UL) /* PCID Mask */
+#define X86_CR3_PCID_NOFLUSH_BIT 63 /* Preserve old PCID */
+#define X86_CR3_PCID_NOFLUSH _BITULL(X86_CR3_PCID_NOFLUSH_BIT)
/*
* Intel CPU features in CR4
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -324,11 +324,45 @@ static __always_inline void setup_smap(s
}
}
+/*
+ * These can have bit 63 set, so we can not just use a plain "or"
+ * instruction to get their value or'd into CR3. It would take
+ * another register. So, we use a memory reference to these
+ * instead.
+ *
+ * This is also handy because systems that do not support
+ * PCIDs just end up or'ing a 0 into their CR3, which does
+ * no harm.
+ */
+__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_KERN_VAR = 0;
+__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_USER_VAR = 0;
+
static void setup_pcid(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_PCID)) {
if (cpu_has(c, X86_FEATURE_PGE)) {
cr4_set_bits(X86_CR4_PCIDE);
+ /*
+ * These variables are used by the entry/exit
+ * code to change PCIDs.
+ */
+#ifdef CONFIG_KAISER
+ X86_CR3_PCID_KERN_VAR = X86_CR3_PCID_KERN_NOFLUSH;
+ X86_CR3_PCID_USER_VAR = X86_CR3_PCID_USER_NOFLUSH;
+#endif
+ /*
+ * INVPCID has two "groups" of types:
+ * 1/2: Invalidate an individual address
+ * 3/4: Invalidate all contexts
+ *
+ * 1/2 take a PCID, but 3/4 do not. So, 3/4
+ * ignore the PCID argument in the descriptor.
+ * But, we have to be careful not to call 1/2
+ * with an actual non-zero PCID in them before
+ * we do the above cr4_set_bits().
+ */
+ if (cpu_has(c, X86_FEATURE_INVPCID))
+ set_cpu_cap(c, X86_FEATURE_INVPCID_SINGLE);
} else {
/*
* flush_tlb_all(), as currently implemented, won't
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -773,7 +773,8 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, u
return 1;
/* PCID can not be enabled when cr3[11:0]!=000H or EFER.LMA=0 */
- if ((kvm_read_cr3(vcpu) & X86_CR3_PCID_MASK) || !is_long_mode(vcpu))
+ if ((kvm_read_cr3(vcpu) & X86_CR3_PCID_ASID_MASK) ||
+ !is_long_mode(vcpu))
return 1;
}
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -239,6 +239,8 @@ static void __init kaiser_init_all_pgds(
} while (0)
extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
+extern unsigned long X86_CR3_PCID_KERN_VAR;
+extern unsigned long X86_CR3_PCID_USER_VAR;
/*
* If anything in here fails, we will likely die on one of the
* first kernel->user transitions and init will die. But, we
@@ -289,6 +291,11 @@ void __init kaiser_init(void)
kaiser_add_user_map_early(&debug_idt_table,
sizeof(gate_desc) * NR_VECTORS,
__PAGE_KERNEL);
+
+ kaiser_add_user_map_early(&X86_CR3_PCID_KERN_VAR, PAGE_SIZE,
+ __PAGE_KERNEL);
+ kaiser_add_user_map_early(&X86_CR3_PCID_USER_VAR, PAGE_SIZE,
+ __PAGE_KERNEL);
}
/* Add a mapping to the shadow mapping, and synchronize the mappings */
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -34,6 +34,46 @@ struct flush_tlb_info {
unsigned long flush_end;
};
+static void load_new_mm_cr3(pgd_t *pgdir)
+{
+ unsigned long new_mm_cr3 = __pa(pgdir);
+
+ /*
+ * KAISER, plus PCIDs needs some extra work here. But,
+ * if either of features is not present, we need no
+ * PCIDs here and just do a normal, full TLB flush with
+ * the write_cr3()
+ */
+ if (!IS_ENABLED(CONFIG_KAISER) ||
+ !cpu_feature_enabled(X86_FEATURE_PCID))
+ goto out_set_cr3;
+ /*
+ * We reuse the same PCID for different tasks, so we must
+ * flush all the entires for the PCID out when we change
+ * tasks.
+ */
+ new_mm_cr3 = X86_CR3_PCID_KERN_FLUSH | __pa(pgdir);
+
+ /*
+ * The flush from load_cr3() may leave old TLB entries
+ * for userspace in place. We must flush that context
+ * separately. We can theoretically delay doing this
+ * until we actually load up the userspace CR3, but
+ * that's a bit tricky. We have to have the "need to
+ * flush userspace PCID" bit per-cpu and check it in the
+ * exit-to-userspace paths.
+ */
+ invpcid_flush_single_context(X86_CR3_PCID_ASID_USER);
+
+out_set_cr3:
+ /*
+ * Caution: many callers of this function expect
+ * that load_cr3() is serializing and orders TLB
+ * fills with respect to the mm_cpumask writes.
+ */
+ write_cr3(new_mm_cr3);
+}
+
/*
* We cannot call mmdrop() because we are in interrupt context,
* instead update mm->cpu_vm_mask.
@@ -45,7 +85,7 @@ void leave_mm(int cpu)
BUG();
if (cpumask_test_cpu(cpu, mm_cpumask(active_mm))) {
cpumask_clear_cpu(cpu, mm_cpumask(active_mm));
- load_cr3(swapper_pg_dir);
+ load_new_mm_cr3(swapper_pg_dir);
/*
* This gets called in the idle path where RCU
* functions differently. Tracing normally
@@ -120,7 +160,7 @@ void switch_mm_irqs_off(struct mm_struct
* ordering guarantee we need.
*
*/
- load_cr3(next->pgd);
+ load_new_mm_cr3(next->pgd);
trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
@@ -167,7 +207,7 @@ void switch_mm_irqs_off(struct mm_struct
* As above, load_cr3() is serializing and orders TLB
* fills with respect to the mm_cpumask write.
*/
- load_cr3(next->pgd);
+ load_new_mm_cr3(next->pgd);
trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
load_mm_cr4(next);
load_mm_ldt(next);
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
There's a 0x1000 in various places, which looks better with a name.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/entry/entry_64.S | 4 ++--
arch/x86/include/asm/kaiser.h | 7 +++++--
2 files changed, 7 insertions(+), 4 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1318,7 +1318,7 @@ ENTRY(nmi)
movq %cr3, %rax
pushq %rax
#ifdef CONFIG_KAISER_REAL_SWITCH
- andq $(~0x1000), %rax
+ andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
#endif
movq %rax, %cr3
#endif
@@ -1561,7 +1561,7 @@ end_repeat_nmi:
movq %cr3, %rax
pushq %rax
#ifdef CONFIG_KAISER_REAL_SWITCH
- andq $(~0x1000), %rax
+ andq $(~KAISER_SHADOW_PGD_OFFSET), %rax
#endif
movq %rax, %cr3
#endif
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -13,13 +13,16 @@
* A minimalistic kernel mapping holds the parts needed to be mapped in user
* mode, such as the entry/exit functions of the user space, or the stacks.
*/
+
+#define KAISER_SHADOW_PGD_OFFSET 0x1000
+
#ifdef __ASSEMBLY__
#ifdef CONFIG_KAISER
.macro _SWITCH_TO_KERNEL_CR3 reg
movq %cr3, \reg
#ifdef CONFIG_KAISER_REAL_SWITCH
-andq $(~0x1000), \reg
+andq $(~KAISER_SHADOW_PGD_OFFSET), \reg
#endif
movq \reg, %cr3
.endm
@@ -27,7 +30,7 @@ movq \reg, %cr3
.macro _SWITCH_TO_USER_CR3 reg
movq %cr3, \reg
#ifdef CONFIG_KAISER_REAL_SWITCH
-orq $(0x1000), \reg
+orq $(KAISER_SHADOW_PGD_OFFSET), \reg
#endif
movq \reg, %cr3
.endm
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
Mainly deleting a surfeit of blank lines, and reflowing header comment.
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/include/asm/kaiser.h | 32 +++++++++++++-------------------
1 file changed, 13 insertions(+), 19 deletions(-)
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -1,15 +1,17 @@
#ifndef _ASM_X86_KAISER_H
#define _ASM_X86_KAISER_H
-
-/* This file includes the definitions for the KAISER feature.
- * KAISER is a counter measure against x86_64 side channel attacks on the kernel virtual memory.
- * It has a shodow-pgd for every process. the shadow-pgd has a minimalistic kernel-set mapped,
- * but includes the whole user memory. Within a kernel context switch, or when an interrupt is handled,
- * the pgd is switched to the normal one. When the system switches to user mode, the shadow pgd is enabled.
- * By this, the virtual memory chaches are freed, and the user may not attack the whole kernel memory.
+/*
+ * This file includes the definitions for the KAISER feature.
+ * KAISER is a counter measure against x86_64 side channel attacks on
+ * the kernel virtual memory. It has a shadow pgd for every process: the
+ * shadow pgd has a minimalistic kernel-set mapped, but includes the whole
+ * user memory. Within a kernel context switch, or when an interrupt is handled,
+ * the pgd is switched to the normal one. When the system switches to user mode,
+ * the shadow pgd is enabled. By this, the virtual memory caches are freed,
+ * and the user may not attack the whole kernel memory.
*
- * A minimalistic kernel mapping holds the parts needed to be mapped in user mode, as the entry/exit functions
- * of the user space, or the stacks.
+ * A minimalistic kernel mapping holds the parts needed to be mapped in user
+ * mode, such as the entry/exit functions of the user space, or the stacks.
*/
#ifdef __ASSEMBLY__
#ifdef CONFIG_KAISER
@@ -48,13 +50,10 @@ _SWITCH_TO_KERNEL_CR3 %rax
movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
.endm
-
.macro SWITCH_USER_CR3_NO_STACK
-
movq %rax, PER_CPU_VAR(unsafe_stack_register_backup)
_SWITCH_TO_USER_CR3 %rax
movq PER_CPU_VAR(unsafe_stack_register_backup), %rax
-
.endm
#else /* CONFIG_KAISER */
@@ -72,7 +71,6 @@ movq PER_CPU_VAR(unsafe_stack_register_b
#else /* __ASSEMBLY__ */
-
#ifdef CONFIG_KAISER
/*
* Upon kernel/user mode switch, it may happen that the address
@@ -80,7 +78,6 @@ movq PER_CPU_VAR(unsafe_stack_register_b
* stored. To change the address space, another register is
* needed. A register therefore has to be stored/restored.
*/
-
DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup);
/**
@@ -95,7 +92,6 @@ DECLARE_PER_CPU_USER_MAPPED(unsigned lon
*/
extern int kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags);
-
/**
* kaiser_remove_mapping - unmap a virtual memory part of the shadow mapping
* @addr: the start address of the range
@@ -104,12 +100,12 @@ extern int kaiser_add_mapping(unsigned l
extern void kaiser_remove_mapping(unsigned long start, unsigned long size);
/**
- * kaiser_initialize_mapping - Initalize the shadow mapping
+ * kaiser_init - Initialize the shadow mapping
*
* Most parts of the shadow mapping can be mapped upon boot
* time. Only per-process things like the thread stacks
* or a new LDT have to be mapped at runtime. These boot-
- * time mappings are permanent and nevertunmapped.
+ * time mappings are permanent and never unmapped.
*/
extern void kaiser_init(void);
@@ -117,6 +113,4 @@ extern void kaiser_init(void);
#endif /* __ASSEMBLY */
-
-
#endif /* _ASM_X86_KAISER_H */
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hugh Dickins <[email protected]>
kaiser_add_user_map() took no notice when kaiser_pagetable_walk() failed.
And avoid its might_sleep() when atomic (though atomic at present unused).
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/mm/kaiser.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -98,11 +98,11 @@ static pte_t *kaiser_pagetable_walk(unsi
pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(address));
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
- might_sleep();
if (is_atomic) {
gfp &= ~GFP_KERNEL;
gfp |= __GFP_HIGH | __GFP_ATOMIC;
- }
+ } else
+ might_sleep();
if (pgd_none(*pgd)) {
WARN_ONCE(1, "All shadow pgds should have been populated");
@@ -159,13 +159,17 @@ int kaiser_add_user_map(const void *__st
unsigned long end_addr = PAGE_ALIGN(start_addr + size);
unsigned long target_address;
- for (;address < end_addr; address += PAGE_SIZE) {
+ for (; address < end_addr; address += PAGE_SIZE) {
target_address = get_pa_from_mapping(address);
if (target_address == -1) {
ret = -EIO;
break;
}
pte = kaiser_pagetable_walk(address, false);
+ if (!pte) {
+ ret = -ENOMEM;
+ break;
+ }
if (pte_none(*pte)) {
set_pte(pte, __pte(flags | target_address));
} else {
On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
> 4.9-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Borislav Petkov <[email protected]>
>
>
> AMD (and possibly other vendors) are not affected by the leak
> KAISER is protecting against.
[...]
> +void __init kaiser_check_boottime_disable(void)
> +{
> + bool enable = true;
> + char arg[5];
> + int ret;
> +
> + ret = cmdline_find_option(boot_command_line, "pti", arg, sizeof(arg));
> + if (ret > 0) {
> + if (!strncmp(arg, "on", 2))
> + goto enable;
> +
> + if (!strncmp(arg, "off", 3))
> + goto disable;
> +
> + if (!strncmp(arg, "auto", 4))
> + goto skip;
> + }
> +
> + if (cmdline_find_option_bool(boot_command_line, "nopti"))
> + goto disable;
> +
> +skip:
> + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
> + goto disable;
[...]
No such exception has been added upstream, so I don't think it's
appropriate to add it in stable.
Ben.
--
Ben Hutchings
Quantity is no substitute for quality, but it's the only one we've got.
On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.75 release.
> There are 39 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
[...]
This seems to be missing a backport of:
commit 85900ea51577e31b186e523c8f4e068c79ecc7d3
Author: Andy Lutomirski <[email protected]>
Date: Tue Dec 12 07:56:42 2017 -0800
x86/pti: Map the vsyscall page if needed
without which, KPTI will break some older user-space.
Ben.
--
Ben Hutchings
Quantity is no substitute for quality, but it's the only one we've got.
On Wed, Jan 3, 2018 at 5:24 PM, Ben Hutchings <[email protected]> wrote:
> On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
>> This is the start of the stable review cycle for the 4.9.75 release.
>> There are 39 patches in this series, all will be posted as a response
>> to this one. If anyone has any issues with these being applied, please
>> let me know.
> [...]
>
> This seems to be missing a backport of:
>
> commit 85900ea51577e31b186e523c8f4e068c79ecc7d3
> Author: Andy Lutomirski <[email protected]>
> Date: Tue Dec 12 07:56:42 2017 -0800
>
> x86/pti: Map the vsyscall page if needed
>
> without which, KPTI will break some older user-space.
You're (kind of) right: I did warn Greg of that yesterday, and we were
both vaguely hoping that someone else could fill in that blank more
quickly than I'd get there.
I doubt it's an actual backport of Andy's 85900ea51577 that's needed -
I'd expect his to depend on at least some of the improved
infrastructure in 4.15-rc, rather than the old-style kaiser-mapping
employed in these backports.
Andrea has a RHEL7 patch for this, and I have a 3.2 patch derived from
Andrea's, but neither would be right for 4.9 or 4.4 as is: I think I'm
going to have to drop today's priority, and attend to this lacuna
tomorrow.
Hugh
On Wed, Jan 3, 2018 at 8:07 PM, Hugh Dickins <[email protected]> wrote:
> On Wed, Jan 3, 2018 at 5:24 PM, Ben Hutchings <[email protected]> wrote:
>> On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
>>> This is the start of the stable review cycle for the 4.9.75 release.
>>> There are 39 patches in this series, all will be posted as a response
>>> to this one. If anyone has any issues with these being applied, please
>>> let me know.
>> [...]
>>
>> This seems to be missing a backport of:
>>
>> commit 85900ea51577e31b186e523c8f4e068c79ecc7d3
>> Author: Andy Lutomirski <[email protected]>
>> Date: Tue Dec 12 07:56:42 2017 -0800
>>
>> x86/pti: Map the vsyscall page if needed
>>
>> without which, KPTI will break some older user-space.
>
> You're (kind of) right: I did warn Greg of that yesterday, and we were
> both vaguely hoping that someone else could fill in that blank more
> quickly than I'd get there.
>
> I doubt it's an actual backport of Andy's 85900ea51577 that's needed -
> I'd expect his to depend on at least some of the improved
> infrastructure in 4.15-rc, rather than the old-style kaiser-mapping
> employed in these backports.
>
> Andrea has a RHEL7 patch for this, and I have a 3.2 patch derived from
> Andrea's, but neither would be right for 4.9 or 4.4 as is: I think I'm
> going to have to drop today's priority, and attend to this lacuna
> tomorrow.
>
I think what you need to backport is:
"x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable
hierarchy" to get the permission bits right
and maybe the big simplification of
kaiser_whatever_its_called_set_pgd(). The latter is going to be a
mess if you're still using the old code. Sorry. But even with the
crappy old code, kaiser_add_mapping() on the vsyscall page plus the
latter _PAGE_USER bit plus the call to the new _PAGE_USER code in
"x86/pti: Map the vsyscall page if needed" should do it.
If you skip all this and only get vsyscall emulation working such that
vsyscall page *reads* don't work from user mode, you're going to
encounter weird problems with programs like "pin". Apparently people
use these things.
On 4 January 2018 at 01:41, Greg Kroah-Hartman
<[email protected]> wrote:
> This is the start of the stable review cycle for the 4.9.75 release.
> There are 39 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
Results from Linaro’s test farm.
No regressions on arm64, arm and x86_64.
Summary
------------------------------------------------------------------------
kernel: 4.9.75-rc1
git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git branch: linux-4.9.y
git commit: d88d440098ee3b1a6004fc6ed442e5cc6f9befca
git describe: v4.9.74-40-gd88d440098ee
Test details: https://qa-reports.linaro.org/lkft/linux-stable-rc-4.9-oe/build/v4.9.74-40-gd88d440098ee
No regressions (compared to build v4.9.74-38-g8cb1a8d5571f)
Boards, architectures and test suites:
-------------------------------------
hi6220-hikey - arm64
* boot - pass: 20,
* kselftest - pass: 40, skip: 23
* libhugetlbfs - pass: 90, skip: 1
* ltp-cap_bounds-tests - pass: 2,
* ltp-containers-tests - pass: 64,
* ltp-fcntl-locktests-tests - pass: 2,
* ltp-filecaps-tests - pass: 2,
* ltp-fs-tests - pass: 60,
* ltp-fs_bind-tests - pass: 2,
* ltp-fs_perms_simple-tests - pass: 19,
* ltp-fsx-tests - pass: 2,
* ltp-hugetlb-tests - pass: 21, skip: 1
* ltp-io-tests - pass: 3,
* ltp-ipc-tests - pass: 9,
* ltp-math-tests - pass: 11,
* ltp-nptl-tests - pass: 2,
* ltp-pty-tests - pass: 4,
* ltp-sched-tests - pass: 14,
* ltp-securebits-tests - pass: 4,
* ltp-syscalls-tests - pass: 983, skip: 121
* ltp-timers-tests - pass: 12,
juno-r2 - arm64
* boot - pass: 20,
* kselftest - pass: 40, skip: 23
* libhugetlbfs - pass: 90, skip: 1
* ltp-cap_bounds-tests - pass: 2,
* ltp-containers-tests - pass: 64,
* ltp-fcntl-locktests-tests - pass: 2,
* ltp-filecaps-tests - pass: 2,
* ltp-fs_bind-tests - pass: 2,
* ltp-fs_perms_simple-tests - pass: 19,
* ltp-fsx-tests - pass: 2,
* ltp-hugetlb-tests - pass: 22,
* ltp-io-tests - pass: 3,
* ltp-ipc-tests - pass: 9,
* ltp-math-tests - pass: 11,
* ltp-nptl-tests - pass: 2,
* ltp-pty-tests - pass: 4,
* ltp-sched-tests - pass: 14,
* ltp-securebits-tests - pass: 4,
* ltp-syscalls-tests - pass: 987, skip: 121
* ltp-timers-tests - pass: 12,
x15 - arm
* boot - pass: 20,
* kselftest - pass: 37, skip: 25
* libhugetlbfs - pass: 87, skip: 1
* ltp-cap_bounds-tests - pass: 2,
* ltp-containers-tests - pass: 64,
* ltp-fcntl-locktests-tests - pass: 2,
* ltp-filecaps-tests - pass: 2,
* ltp-fs-tests - pass: 60,
* ltp-fs_bind-tests - pass: 2,
* ltp-fs_perms_simple-tests - pass: 19,
* ltp-fsx-tests - pass: 2,
* ltp-hugetlb-tests - pass: 20, skip: 2
* ltp-io-tests - pass: 3,
* ltp-ipc-tests - pass: 9,
* ltp-math-tests - pass: 11,
* ltp-nptl-tests - pass: 2,
* ltp-pty-tests - pass: 4,
* ltp-sched-tests - pass: 13, skip: 1
* ltp-securebits-tests - pass: 4,
* ltp-syscalls-tests - pass: 1037, skip: 66
* ltp-timers-tests - pass: 12,
x86_64
* boot - pass: 20,
* kselftest - pass: 53, skip: 24
* libhugetlbfs - pass: 90, skip: 1
* ltp-cap_bounds-tests - pass: 2,
* ltp-containers-tests - pass: 63,
* ltp-fcntl-locktests-tests - pass: 2,
* ltp-filecaps-tests - pass: 2,
* ltp-fs-tests - pass: 61, skip: 1
* ltp-fs_bind-tests - pass: 2,
* ltp-fs_perms_simple-tests - pass: 19,
* ltp-fsx-tests - pass: 2,
* ltp-hugetlb-tests - pass: 22,
* ltp-io-tests - pass: 3,
* ltp-ipc-tests - pass: 9,
* ltp-math-tests - pass: 11,
* ltp-nptl-tests - pass: 2,
* ltp-pty-tests - pass: 4,
* ltp-sched-tests - pass: 9, skip: 1
* ltp-securebits-tests - pass: 4,
* ltp-syscalls-tests - pass: 1014, skip: 116
* ltp-timers-tests - pass: 12,
Documentation - https://collaborate.linaro.org/display/LKFT/Email+Reports
Tested-by: Naresh Kamboju <[email protected]>
On Thu, Jan 04, 2018 at 12:16:08AM +0000, Ben Hutchings wrote:
> No such exception has been added upstream, so I don't think it's
> appropriate to add it in stable.
On its way:
https://git.kernel.org/tip/694d99d40972f12e59a3696effee8a376b79d7c8
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
On Thu, Jan 04, 2018 at 08:05:50AM +0100, Borislav Petkov wrote:
> On Thu, Jan 04, 2018 at 12:16:08AM +0000, Ben Hutchings wrote:
> > No such exception has been added upstream, so I don't think it's
> > appropriate to add it in stable.
>
> On its way:
>
> https://git.kernel.org/tip/694d99d40972f12e59a3696effee8a376b79d7c8
Now in Linus's tree, so I'll leave this as-is, thanks.
greg k-h
On Thu, Jan 04, 2018 at 01:24:55AM +0000, Ben Hutchings wrote:
> On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
> > This is the start of the stable review cycle for the 4.9.75 release.
> > There are 39 patches in this series, all will be posted as a response
> > to this one. If anyone has any issues with these being applied, please
> > let me know.
> [...]
>
> This seems to be missing a backport of:
>
> commit 85900ea51577e31b186e523c8f4e068c79ecc7d3
> Author: Andy Lutomirski <[email protected]>
> Date: Tue Dec 12 07:56:42 2017 -0800
>
> x86/pti: Map the vsyscall page if needed
>
> without which, KPTI will break some older user-space.
Ah crap, thanks, I forgot that one in all of this mess, I'll go queue it
up now.
greg k-h
On Thu, Jan 04, 2018 at 08:39:41AM +0100, Greg Kroah-Hartman wrote:
> On Thu, Jan 04, 2018 at 01:24:55AM +0000, Ben Hutchings wrote:
> > On Wed, 2018-01-03 at 21:11 +0100, Greg Kroah-Hartman wrote:
> > > This is the start of the stable review cycle for the 4.9.75 release.
> > > There are 39 patches in this series, all will be posted as a response
> > > to this one. If anyone has any issues with these being applied, please
> > > let me know.
> > [...]
> >
> > This seems to be missing a backport of:
> >
> > commit 85900ea51577e31b186e523c8f4e068c79ecc7d3
> > Author: Andy Lutomirski <[email protected]>
> > Date: Tue Dec 12 07:56:42 2017 -0800
> >
> > x86/pti: Map the vsyscall page if needed
> >
> > without which, KPTI will break some older user-space.
>
> Ah crap, thanks, I forgot that one in all of this mess, I'll go queue it
> up now.
Oops, no, nevermind, I need to read the rest of this thread before
responding. I'll leave this as-is for now, and wait for the real fixup.
Or, if I get done with everything else today, work on it myself
(doubtful, this is going to be an "interesting" day...)
thanks,
greg k-h
On Thu, Jan 04, 2018 at 12:31:49PM +0530, Naresh Kamboju wrote:
> On 4 January 2018 at 01:41, Greg Kroah-Hartman
> <[email protected]> wrote:
> > This is the start of the stable review cycle for the 4.9.75 release.
> > There are 39 patches in this series, all will be posted as a response
> > to this one. If anyone has any issues with these being applied, please
> > let me know.
> >
> > Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
> > Anything received after that time might be too late.
> >
> > The whole patch series can be found in one patch at:
> > kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
> > or in the git tree and branch at:
> > git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> > and the diffstat can be found below.
> >
> > thanks,
> >
> > greg k-h
>
> Results from Linaro’s test farm.
> No regressions on arm64, arm and x86_64.
Thanks for testing both of these and letting me know.
greg k-h
On Wed, Jan 03, 2018 at 09:11:14PM +0100, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.75 release.
> There are 39 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
For v4.9.74-40-gd88d440:
Build results:
total: 145 pass: 145 fail: 0
Qemu test results:
total: 126 pass: 126 fail: 0
Details are available at http://kerneltests.org/builders.
Guenter
On 01/03/2018 01:11 PM, Greg Kroah-Hartman wrote:
> This is the start of the stable review cycle for the 4.9.75 release.
> There are 39 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
>
Based on the email threads, I expected to see issues, however,
compiled and booted on my test system. No dmesg regressions.
thanks,
-- Shuah
On Thu, Jan 4, 2018 at 5:11 AM, Greg Kroah-Hartman
<[email protected]> wrote:
> This is the start of the stable review cycle for the 4.9.75 release.
> There are 39 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let me know.
>
> Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
> Anything received after that time might be too late.
>
> The whole patch series can be found in one patch at:
> kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
> or in the git tree and branch at:
> git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> and the diffstat can be found below.
>
> thanks,
>
> greg k-h
>
This patchset merges correctly with Gentoo patches / GCC 6.4.0 and the
kernel boot up correctly.
https://github.com/gentoo/linux-patches/tree/4.9_001
http://kernel1.amd64.dev.gentoo.org:8010/#/builders/3/builds/47
--
Thanks,
Alice Ferrazzi
Gentoo Kernel Project Leader
Gentoo Foundation Board Member
Mail: Alice Ferrazzi <[email protected]>
PGP: 2E4E 0856 461C 0585 1336 F496 5621 A6B2 8638 781A
On Fri, Jan 05, 2018 at 07:23:48PM +0900, Alice Ferrazzi wrote:
> On Thu, Jan 4, 2018 at 5:11 AM, Greg Kroah-Hartman
> <[email protected]> wrote:
> > This is the start of the stable review cycle for the 4.9.75 release.
> > There are 39 patches in this series, all will be posted as a response
> > to this one. If anyone has any issues with these being applied, please
> > let me know.
> >
> > Responses should be made by Fri Jan 5 19:50:44 UTC 2018.
> > Anything received after that time might be too late.
> >
> > The whole patch series can be found in one patch at:
> > kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.9.75-rc1.gz
> > or in the git tree and branch at:
> > git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.9.y
> > and the diffstat can be found below.
> >
> > thanks,
> >
> > greg k-h
> >
>
> This patchset merges correctly with Gentoo patches / GCC 6.4.0 and the
> kernel boot up correctly.
> https://github.com/gentoo/linux-patches/tree/4.9_001
> http://kernel1.amd64.dev.gentoo.org:8010/#/builders/3/builds/47
Great, thanks for testing and letting me know.
greg k-h