PER_CPU_VAR(kernel_stack) is redundant.
In 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
In 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).
PER_CPU_VAR(kernel_stack) will be deleted by a separate change.
Signed-off-by: Denys Vlasenko <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: "H. Peter Anvin" <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Oleg Nesterov <[email protected]>
CC: Frederic Weisbecker <[email protected]>
CC: Alexei Starovoitov <[email protected]>
CC: Will Drewry <[email protected]>
CC: Kees Cook <[email protected]>
CC: [email protected]
CC: [email protected]
---
arch/x86/ia32/ia32entry.S | 2 +-
arch/x86/include/asm/thread_info.h | 8 +++++++-
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
4 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 9537dcb..3f28678 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -352,7 +352,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index b4bdec3..d656a36 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -198,9 +198,15 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
/* Load thread_info address into "reg" */
+#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
+ _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
+#else
+#define GET_THREAD_INFO(reg) \
+ _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
+ _ASM_SUB $(THREAD_SIZE),reg ;
+#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index e952f6b..508fe4e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 985fc3e..acc49e0 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -15,6 +15,7 @@
#include <asm/percpu.h>
#include <asm/processor-flags.h>
#include <asm/segment.h>
+#include <asm/asm-offsets.h>
#include <xen/interface/xen.h>
@@ -69,7 +70,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -88,7 +89,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
--
1.8.1.4
Signed-off-by: Denys Vlasenko <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: "H. Peter Anvin" <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Oleg Nesterov <[email protected]>
CC: Frederic Weisbecker <[email protected]>
CC: Alexei Starovoitov <[email protected]>
CC: Will Drewry <[email protected]>
CC: Kees Cook <[email protected]>
CC: [email protected]
CC: [email protected]
---
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/kernel/cpu/common.c | 4 ----
arch/x86/kernel/process_32.c | 5 +----
arch/x86/kernel/process_64.c | 3 ---
arch/x86/kernel/smpboot.c | 2 --
5 files changed, 1 insertion(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d656a36..4722889 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -177,8 +177,6 @@ struct thread_info {
*/
#ifndef __ASSEMBLY__
-DECLARE_PER_CPU(unsigned long, kernel_stack);
-
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a62cf04..6bec0b5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1155,10 +1155,6 @@ static __init int setup_disablecpuid(char *arg)
}
__setup("clearcpuid=", setup_disablecpuid);
-DEFINE_PER_CPU(unsigned long, kernel_stack) =
- (unsigned long)&init_thread_union + THREAD_SIZE;
-EXPORT_PER_CPU_SYMBOL(kernel_stack);
-
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8ed2106..a99900c 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -302,13 +302,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
arch_end_context_switch(next_p);
/*
- * Reload esp0, kernel_stack, and current_top_of_stack. This changes
+ * Reload esp0 and cpu_current_top_of_stack. This changes
* current_thread_info().
*/
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) +
- THREAD_SIZE);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4baaa97..342257c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -409,9 +409,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/* Reload esp0 and ss1. This changes current_thread_info(). */
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
-
/*
* Now maybe reload the debug registers and handle I/O bitmaps
*/
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 50e547e..023cccf 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,8 +792,6 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
clear_tsk_thread_flag(idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
#endif
- per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) + THREAD_SIZE;
}
/*
--
1.8.1.4
32-bit code has PER_CPU_VAR(cpu_current_top_of_stack).
64-bit code uses somewhat more obscure PER_CPU_VAR(cpu_tss + TSS_sp0).
Define cpu_current_top_of_stack macro on CONFIG_X86_64 so that
PER_CPU_VAR(cpu_current_top_of_stack) expression can be used in both
32-bit and 64-bit code.
Signed-off-by: Denys Vlasenko <[email protected]>
CC: Linus Torvalds <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Borislav Petkov <[email protected]>
CC: "H. Peter Anvin" <[email protected]>
CC: Andy Lutomirski <[email protected]>
CC: Oleg Nesterov <[email protected]>
CC: Frederic Weisbecker <[email protected]>
CC: Alexei Starovoitov <[email protected]>
CC: Will Drewry <[email protected]>
CC: Kees Cook <[email protected]>
CC: [email protected]
CC: [email protected]
---
The idea of this patch was suggested by Steven Rostedt.
I'm okay if only patches 1 and 2 will be applied.
arch/x86/ia32/ia32entry.S | 4 ++--
arch/x86/include/asm/processor.h | 2 ++
arch/x86/include/asm/thread_info.h | 10 ++++------
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
5 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 3f28678..c06a9c6 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -119,7 +119,7 @@ ENTRY(ia32_sysenter_target)
* it is too small to ever cause noticeable irq latency.
*/
SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
@@ -352,7 +352,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 23ba676..3754dac 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -304,6 +304,8 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
#ifdef CONFIG_X86_32
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
+#else
+#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
#endif
/*
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 4722889..5b1e833 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -195,16 +195,14 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
+#ifdef CONFIG_X86_64
+#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
+#endif
+
/* Load thread_info address into "reg" */
-#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
-#else
-#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
- _ASM_SUB $(THREAD_SIZE),reg ;
-#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 508fe4e..5db3488 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index acc49e0..5e15e92 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -16,6 +16,7 @@
#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
#include <xen/interface/xen.h>
@@ -70,7 +71,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -89,7 +90,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
--
1.8.1.4
On Fri, Apr 24, 2015 at 5:31 PM, Denys Vlasenko <[email protected]>
> diff --git a/arch/x86/include/asm/processor.h
b/arch/x86/include/asm/processor.h
> index 23ba676..3754dac 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -304,6 +304,8 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss);
>
> #ifdef CONFIG_X86_32
> DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
> +#else
> +#define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
> #endif
>
> /*
> diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
Oops... this hunk (one touching processor.h) shouldn't be there.
It is bogus. It works simply because this define isn't used
by 64-bit builds. Just drop this hunk. The rest is correct.
On Fri, Apr 24, 2015 at 8:31 AM, Denys Vlasenko <[email protected]> wrote:
> Signed-off-by: Denys Vlasenko <[email protected]>
> CC: Linus Torvalds <[email protected]>
> CC: Steven Rostedt <[email protected]>
> CC: Ingo Molnar <[email protected]>
> CC: Borislav Petkov <[email protected]>
> CC: "H. Peter Anvin" <[email protected]>
> CC: Andy Lutomirski <[email protected]>
> CC: Oleg Nesterov <[email protected]>
> CC: Frederic Weisbecker <[email protected]>
> CC: Alexei Starovoitov <[email protected]>
> CC: Will Drewry <[email protected]>
> CC: Kees Cook <[email protected]>
> CC: [email protected]
> CC: [email protected]
Acked-by: Andy Lutomirski <[email protected]>
Commit-ID: 63332a8455d8310b77d38779c6c21a660a8d9feb
Gitweb: http://git.kernel.org/tip/63332a8455d8310b77d38779c6c21a660a8d9feb
Author: Denys Vlasenko <[email protected]>
AuthorDate: Fri, 24 Apr 2015 17:31:33 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 8 May 2015 13:43:52 +0200
x86/entry: Stop using PER_CPU_VAR(kernel_stack)
PER_CPU_VAR(kernel_stack) is redundant:
- On the 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
- On the 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).
PER_CPU_VAR(kernel_stack) will be deleted by a separate change.
Signed-off-by: Denys Vlasenko <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/ia32/ia32entry.S | 2 +-
arch/x86/include/asm/thread_info.h | 8 +++++++-
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
4 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 2ab0f71..1b1330c 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -346,7 +346,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index b4bdec3..d656a36 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -198,9 +198,15 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
/* Load thread_info address into "reg" */
+#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
+ _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
+#else
+#define GET_THREAD_INFO(reg) \
+ _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
+ _ASM_SUB $(THREAD_SIZE),reg ;
+#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 7423e3e..c13b86b 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack),%rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index a2cabb8..5aa7ec6 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -15,6 +15,7 @@
#include <asm/percpu.h>
#include <asm/processor-flags.h>
#include <asm/segment.h>
+#include <asm/asm-offsets.h>
#include <xen/interface/xen.h>
@@ -53,7 +54,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -72,7 +73,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(kernel_stack), %rsp
+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)
Commit-ID: fed7c3f0f750f225317828d691e9eb76eec887b3
Gitweb: http://git.kernel.org/tip/fed7c3f0f750f225317828d691e9eb76eec887b3
Author: Denys Vlasenko <[email protected]>
AuthorDate: Fri, 24 Apr 2015 17:31:34 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 8 May 2015 13:49:43 +0200
x86/entry: Remove unused 'kernel_stack' per-cpu variable
Signed-off-by: Denys Vlasenko <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/include/asm/thread_info.h | 2 --
arch/x86/kernel/cpu/common.c | 4 ----
arch/x86/kernel/process_32.c | 5 +----
arch/x86/kernel/process_64.c | 3 ---
arch/x86/kernel/smpboot.c | 2 --
5 files changed, 1 insertion(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d656a36..4722889 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -177,8 +177,6 @@ struct thread_info {
*/
#ifndef __ASSEMBLY__
-DECLARE_PER_CPU(unsigned long, kernel_stack);
-
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a62cf04..6bec0b5 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1155,10 +1155,6 @@ static __init int setup_disablecpuid(char *arg)
}
__setup("clearcpuid=", setup_disablecpuid);
-DEFINE_PER_CPU(unsigned long, kernel_stack) =
- (unsigned long)&init_thread_union + THREAD_SIZE;
-EXPORT_PER_CPU_SYMBOL(kernel_stack);
-
#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8ed2106..a99900c 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -302,13 +302,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
arch_end_context_switch(next_p);
/*
- * Reload esp0, kernel_stack, and current_top_of_stack. This changes
+ * Reload esp0 and cpu_current_top_of_stack. This changes
* current_thread_info().
*/
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) +
- THREAD_SIZE);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ddfdbf7..8213450 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -409,9 +409,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/* Reload esp0 and ss1. This changes current_thread_info(). */
load_sp0(tss, next);
- this_cpu_write(kernel_stack,
- (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
-
/*
* Now maybe reload the debug registers and handle I/O bitmaps
*/
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 50e547e..023cccf 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,8 +792,6 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
clear_tsk_thread_flag(idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
#endif
- per_cpu(kernel_stack, cpu) =
- (unsigned long)task_stack_page(idle) + THREAD_SIZE;
}
/*
Commit-ID: 3a23208e69679597e767cf3547b1a30dd845d9b5
Gitweb: http://git.kernel.org/tip/3a23208e69679597e767cf3547b1a30dd845d9b5
Author: Denys Vlasenko <[email protected]>
AuthorDate: Fri, 24 Apr 2015 17:31:35 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Fri, 8 May 2015 13:50:02 +0200
x86/entry: Define 'cpu_current_top_of_stack' for 64-bit code
32-bit code has PER_CPU_VAR(cpu_current_top_of_stack).
64-bit code uses somewhat more obscure: PER_CPU_VAR(cpu_tss + TSS_sp0).
Define the 'cpu_current_top_of_stack' macro on CONFIG_X86_64
as well so that the PER_CPU_VAR(cpu_current_top_of_stack)
expression can be used in both 32-bit and 64-bit code.
Signed-off-by: Denys Vlasenko <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/ia32/ia32entry.S | 4 ++--
arch/x86/include/asm/thread_info.h | 10 ++++------
arch/x86/kernel/entry_64.S | 2 +-
arch/x86/xen/xen-asm_64.S | 5 +++--
4 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 1b1330c..63450a5 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -113,7 +113,7 @@ ENTRY(ia32_sysenter_target)
* it is too small to ever cause noticeable irq latency.
*/
SWAPGS_UNSAFE_STACK
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
@@ -346,7 +346,7 @@ ENTRY(ia32_cstar_target)
SWAPGS_UNSAFE_STACK
movl %esp,%r8d
CFI_REGISTER rsp,r8
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
ENABLE_INTERRUPTS(CLBR_NONE)
/* Zero-extending 32-bit regs, do not remove */
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 4722889..225ee54 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -195,16 +195,14 @@ static inline unsigned long current_stack_pointer(void)
#else /* !__ASSEMBLY__ */
+#ifdef CONFIG_X86_64
+# define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
+#endif
+
/* Load thread_info address into "reg" */
-#ifdef CONFIG_X86_32
#define GET_THREAD_INFO(reg) \
_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
_ASM_SUB $(THREAD_SIZE),reg ;
-#else
-#define GET_THREAD_INFO(reg) \
- _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
- _ASM_SUB $(THREAD_SIZE),reg ;
-#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index c13b86b..09c3f9e 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -216,7 +216,7 @@ ENTRY(system_call)
GLOBAL(system_call_after_swapgs)
movq %rsp,PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp
/* Construct struct pt_regs on stack */
pushq_cfi $__USER_DS /* pt_regs->ss */
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index 5aa7ec6..04529e6 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -16,6 +16,7 @@
#include <asm/processor-flags.h>
#include <asm/segment.h>
#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
#include <xen/interface/xen.h>
@@ -54,7 +55,7 @@ ENTRY(xen_sysret64)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER_DS
pushq PER_CPU_VAR(rsp_scratch)
@@ -73,7 +74,7 @@ ENTRY(xen_sysret32)
* still with the kernel gs, so we can easily switch back
*/
movq %rsp, PER_CPU_VAR(rsp_scratch)
- movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
+ movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
pushq $__USER32_DS
pushq PER_CPU_VAR(rsp_scratch)