Changes since v4:
* change comment style in entry_64.S to C89
(nobody is using assembler syntax comments there).
* the bool function restore_r2 shouldn't return 2,
that's a little confusing.
* Test whether the compiler supports -mprofile-kernel
and only then define CC_USING_MPROFILE_KERNEL
* also make the return value of klp_check_compiler_support
depend on that.
Major changes since v3:
* the graph tracer works now.
It turned out the stack frame it tried to manipulate does not
exist at that point.
* changes only needed in order to support -mprofile-kernel are now
in a separate patch, prepended.
* Kconfig cleanup so this is only selectable on ppc64le.
Torsten Duwe (9):
ppc64 (le): prepare for -mprofile-kernel
ppc64le FTRACE_WITH_REGS implementation
ppc use ftrace_modify_all_code default
ppc64 ftrace_with_regs configuration variables
ppc64 ftrace_with_regs: spare early boot and low level
ppc64 ftrace: disable profiling for some functions
ppc64 ftrace: disable profiling for some files
Implement kernel live patching for ppc64le (ABIv2)
Enable LIVEPATCH to be configured on ppc64le and add livepatch.o if it
is selected.
arch/powerpc/Kconfig | 7 ++
arch/powerpc/Makefile | 10 +++
arch/powerpc/include/asm/ftrace.h | 5 ++
arch/powerpc/include/asm/livepatch.h | 45 ++++++++++
arch/powerpc/kernel/Makefile | 13 +--
arch/powerpc/kernel/entry_64.S | 164 ++++++++++++++++++++++++++++++++++-
arch/powerpc/kernel/ftrace.c | 88 ++++++++++++++-----
arch/powerpc/kernel/livepatch.c | 38 ++++++++
arch/powerpc/kernel/module_64.c | 38 +++++++-
arch/powerpc/kernel/process.c | 2 +-
arch/powerpc/lib/Makefile | 4 +-
arch/powerpc/mm/fault.c | 2 +-
arch/powerpc/mm/hash_utils_64.c | 18 ++--
arch/powerpc/mm/hugetlbpage-hash64.c | 2 +-
arch/powerpc/mm/hugetlbpage.c | 4 +-
arch/powerpc/mm/mem.c | 2 +-
arch/powerpc/mm/pgtable_64.c | 2 +-
arch/powerpc/mm/slb.c | 6 +-
arch/powerpc/mm/slice.c | 8 +-
kernel/trace/Kconfig | 5 ++
20 files changed, 409 insertions(+), 54 deletions(-)
create mode 100644 arch/powerpc/include/asm/livepatch.h
create mode 100644 arch/powerpc/kernel/livepatch.c
--
1.8.5.6
The gcc switch -mprofile-kernel, available for ppc64 on gcc > 4.8.5,
allows to call _mcount very early in the function, which low-level
ASM code and code patching functions need to consider.
Especially the link register and the parameter registers are still
alive and not yet saved into a new stack frame.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/kernel/entry_64.S | 44 +++++++++++++++++++++++++++++++++++++++--
arch/powerpc/kernel/ftrace.c | 12 +++++++++--
arch/powerpc/kernel/module_64.c | 13 ++++++++++++
3 files changed, 65 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index a94f155..c3b2e75 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1206,7 +1206,11 @@ _GLOBAL(enter_prom)
#ifdef CONFIG_DYNAMIC_FTRACE
_GLOBAL(mcount)
_GLOBAL(_mcount)
- blr
+ mflr r0
+ mtctr r0
+ ld r0,LRSAVE(r1)
+ mtlr r0
+ bctr
_GLOBAL_TOC(ftrace_caller)
/* Taken from output of objdump from lib64/glibc */
@@ -1262,13 +1266,28 @@ _GLOBAL(ftrace_stub)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
_GLOBAL(ftrace_graph_caller)
+#ifdef CC_USING_MPROFILE_KERNEL
+ /* with -mprofile-kernel, parameter regs are still alive at _mcount */
+ std r10, 104(r1)
+ std r9, 96(r1)
+ std r8, 88(r1)
+ std r7, 80(r1)
+ std r6, 72(r1)
+ std r5, 64(r1)
+ std r4, 56(r1)
+ std r3, 48(r1)
+ mfctr r4 /* ftrace_caller has moved local addr here */
+ std r4, 40(r1)
+ mflr r3 /* ftrace_caller has restored LR from stack */
+#else
/* load r4 with local address */
ld r4, 128(r1)
- subi r4, r4, MCOUNT_INSN_SIZE
/* Grab the LR out of the caller stack frame */
ld r11, 112(r1)
ld r3, 16(r11)
+#endif
+ subi r4, r4, MCOUNT_INSN_SIZE
bl prepare_ftrace_return
nop
@@ -1277,6 +1296,26 @@ _GLOBAL(ftrace_graph_caller)
* prepare_ftrace_return gives us the address we divert to.
* Change the LR in the callers stack frame to this.
*/
+
+#ifdef CC_USING_MPROFILE_KERNEL
+ mtlr r3
+
+ ld r0, 40(r1)
+ mtctr r0
+ ld r10, 104(r1)
+ ld r9, 96(r1)
+ ld r8, 88(r1)
+ ld r7, 80(r1)
+ ld r6, 72(r1)
+ ld r5, 64(r1)
+ ld r4, 56(r1)
+ ld r3, 48(r1)
+
+ addi r1, r1, 112
+ mflr r0
+ std r0, LRSAVE(r1)
+ bctr
+#else
ld r11, 112(r1)
std r3, 16(r11)
@@ -1284,6 +1323,7 @@ _GLOBAL(ftrace_graph_caller)
mtlr r0
addi r1, r1, 112
blr
+#endif
_GLOBAL(return_to_handler)
/* need to save return values */
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 44d4d8e..080c525 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -306,11 +306,19 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* The load offset is different depending on the ABI. For simplicity
* just mask it out when doing the compare.
*/
+#ifndef CC_USING_MPROFILE_KERNEL
if ((op[0] != 0x48000008) || ((op[1] & 0xffff0000) != 0xe8410000)) {
- pr_err("Unexpected call sequence: %x %x\n", op[0], op[1]);
+ pr_err("Unexpected call sequence at %p: %x %x\n",
+ ip, op[0], op[1]);
return -EINVAL;
}
-
+#else
+ /* look for patched "NOP" on ppc64 with -mprofile-kernel */
+ if (op[0] != 0x60000000) {
+ pr_err("Unexpected call at %p: %x\n", ip, op[0]);
+ return -EINVAL;
+ }
+#endif
/* If we never set up a trampoline to ftrace_caller, then bail */
if (!rec->arch.mod->arch.tramp) {
pr_err("No ftrace trampoline\n");
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 6838451..5312cd4 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -475,6 +475,19 @@ static unsigned long stub_for_addr(Elf64_Shdr *sechdrs,
static int restore_r2(u32 *instruction, struct module *me)
{
if (*instruction != PPC_INST_NOP) {
+#ifdef CC_USING_MPROFILE_KERNEL
+ /* -mprofile_kernel sequence starting with
+ * mflr r0; std r0, LRSAVE(r1)
+ */
+ if (instruction[-3] == 0x7c0802a6 &&
+ instruction[-2] == 0xf8010010) {
+ /* Nothing to be done here, it's an _mcount
+ * call location and r2 will have to be
+ * restored in the _mcount function.
+ */
+ return 1;
+ };
+#endif
pr_err("%s: Expect noop after relocate, got %08x\n",
me->name, *instruction);
return 0;
--
1.8.5.6
Implement FTRACE_WITH_REGS for powerpc64, on ELF ABI v2.
Initial work started by Vojtech Pavlik, used with permission.
* arch/powerpc/kernel/entry_64.S:
- Implement an effective ftrace_caller that works from
within the kernel binary as well as from modules.
* arch/powerpc/kernel/ftrace.c:
- be prepared to deal with ppc64 ELF ABI v2, especially
calls to _mcount that result from gcc -mprofile-kernel
- a little more error verbosity
* arch/powerpc/kernel/module_64.c:
- do not save the TOC pointer on the trampoline when the
destination is ftrace_caller. This trampoline jump happens from
a function prologue before a new stack frame is set up, so bad
things may happen otherwise...
- relax is_module_trampoline() to recognise the modified
trampoline.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/include/asm/ftrace.h | 5 +++
arch/powerpc/kernel/entry_64.S | 77 +++++++++++++++++++++++++++++++++++++++
arch/powerpc/kernel/ftrace.c | 60 +++++++++++++++++++++++++++---
arch/powerpc/kernel/module_64.c | 25 ++++++++++++-
4 files changed, 160 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index ef89b14..50ca758 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -46,6 +46,8 @@
extern void _mcount(void);
#ifdef CONFIG_DYNAMIC_FTRACE
+# define FTRACE_ADDR ((unsigned long)ftrace_caller)
+# define FTRACE_REGS_ADDR FTRACE_ADDR
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
/* reloction of mcount call site is the same as the address */
@@ -58,6 +60,9 @@ struct dyn_arch_ftrace {
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+#endif
#endif
#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) && !defined(__ASSEMBLY__)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index c3b2e75..294a9ca 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1212,6 +1212,7 @@ _GLOBAL(_mcount)
mtlr r0
bctr
+#ifndef CC_USING_MPROFILE_KERNEL
_GLOBAL_TOC(ftrace_caller)
/* Taken from output of objdump from lib64/glibc */
mflr r3
@@ -1233,6 +1234,82 @@ _GLOBAL(ftrace_graph_stub)
ld r0, 128(r1)
mtlr r0
addi r1, r1, 112
+#else
+_GLOBAL(ftrace_caller)
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+ mflr r0
+ bl 2f
+2: mflr r12
+ mtlr r0
+ mr r0,r2 /* save callee's TOC */
+ addis r2,r12,(.TOC.-ftrace_caller-8)@ha
+ addi r2,r2,(.TOC.-ftrace_caller-8)@l
+#else
+ mr r0,r2
+#endif
+ ld r12,LRSAVE(r1) /* get caller's address */
+
+ stdu r1,-SWITCH_FRAME_SIZE(r1)
+
+ std r12, _LINK(r1)
+ SAVE_8GPRS(0,r1)
+ std r0, 24(r1) /* save TOC */
+ SAVE_8GPRS(8,r1)
+ SAVE_8GPRS(16,r1)
+ SAVE_8GPRS(24,r1)
+
+ addis r3,r2,function_trace_op@toc@ha
+ addi r3,r3,function_trace_op@toc@l
+ ld r5,0(r3)
+
+ mflr r3
+ std r3, _NIP(r1)
+ std r3, 16(r1)
+ subi r3, r3, MCOUNT_INSN_SIZE
+ mfmsr r4
+ std r4, _MSR(r1)
+ mfctr r4
+ std r4, _CTR(r1)
+ mfxer r4
+ std r4, _XER(r1)
+ mr r4, r12
+ addi r6, r1 ,STACK_FRAME_OVERHEAD
+
+.globl ftrace_call
+ftrace_call:
+ bl ftrace_stub
+ nop
+
+ ld r3, _NIP(r1)
+ mtlr r3
+
+ REST_8GPRS(0,r1)
+ REST_8GPRS(8,r1)
+ REST_8GPRS(16,r1)
+ REST_8GPRS(24,r1)
+
+ addi r1, r1, SWITCH_FRAME_SIZE
+
+ ld r12, LRSAVE(r1) /* get caller's address */
+ mtlr r12
+ mr r2,r0 /* restore callee's TOC */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ stdu r1, -112(r1)
+.globl ftrace_graph_call
+ftrace_graph_call:
+ b ftrace_graph_stub
+_GLOBAL(ftrace_graph_stub)
+ addi r1, r1, 112
+#endif
+
+ mflr r0 /* move this LR to CTR */
+ mtctr r0
+
+ ld r0,LRSAVE(r1) /* restore callee's lr at _mcount site */
+ mtlr r0
+ bctr /* jump after _mcount site */
+#endif /* CC_USING_MPROFILE_KERNEL */
_GLOBAL(ftrace_stub)
blr
#else
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 080c525..310137f 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -61,8 +61,11 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
return -EFAULT;
/* Make sure it is what we expect it to be */
- if (replaced != old)
+ if (replaced != old) {
+ pr_err("%p: replaced (%#x) != old (%#x)",
+ (void *)ip, replaced, old);
return -EINVAL;
+ }
/* replace the text with the new text */
if (patch_instruction((unsigned int *)ip, new))
@@ -106,14 +109,16 @@ static int
__ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr)
{
- unsigned int op;
+ unsigned int op, op0, op1, pop;
unsigned long entry, ptr;
unsigned long ip = rec->ip;
void *tramp;
/* read where this goes */
- if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
+ if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
+ pr_err("Fetching opcode failed.\n");
return -EFAULT;
+ }
/* Make sure that that this is still a 24bit jump */
if (!is_bl_op(op)) {
@@ -158,10 +163,46 @@ __ftrace_make_nop(struct module *mod,
*
* Use a b +8 to jump over the load.
*/
- op = 0x48000008; /* b +8 */
- if (patch_instruction((unsigned int *)ip, op))
+ pop = 0x48000008; /* b +8 */
+
+ /*
+ * Check what is in the next instruction. We can see ld r2,40(r1), but
+ * on first pass after boot we will see mflr r0.
+ */
+ if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) {
+ pr_err("Fetching op failed.\n");
+ return -EFAULT;
+ }
+
+ if (op != 0xe8410028) { /* ld r2,STACK_OFFSET(r1) */
+
+ if (probe_kernel_read(&op0, (void *)(ip-8), MCOUNT_INSN_SIZE)) {
+ pr_err("Fetching op0 failed.\n");
+ return -EFAULT;
+ }
+
+ if (probe_kernel_read(&op1, (void *)(ip-4), MCOUNT_INSN_SIZE)) {
+ pr_err("Fetching op1 failed.\n");
+ return -EFAULT;
+ }
+
+ /* mflr r0 ; std r0,LRSAVE(r1) */
+ if (op0 != 0x7c0802a6 && op1 != 0xf8010010) {
+ pr_err("Unexpected instructions around bl\n"
+ "when enabling dynamic ftrace!\t"
+ "(%08x,%08x,bl,%08x)\n", op0, op1, op);
+ return -EINVAL;
+ }
+
+ /* When using -mkernel_profile there is no load to jump over */
+ pop = PPC_INST_NOP;
+ }
+
+ if (patch_instruction((unsigned int *)ip, pop)) {
+ pr_err("Patching NOP failed.\n");
return -EPERM;
+ }
return 0;
}
@@ -287,6 +328,13 @@ int ftrace_make_nop(struct module *mod,
#ifdef CONFIG_MODULES
#ifdef CONFIG_PPC64
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+ unsigned long addr)
+{
+ return ftrace_make_call(rec, addr);
+}
+#endif
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
@@ -338,7 +386,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return 0;
}
-#else
+#else /* !CONFIG_PPC64: */
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 5312cd4..7218b37 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -138,12 +138,25 @@ static u32 ppc64_stub_insns[] = {
0x4e800420 /* bctr */
};
+#ifdef CC_USING_MPROFILE_KERNEL
+/* In case of _mcount calls or dynamic ftracing, Do not save the
+ * current callee's TOC (in R2) again into the original caller's stack
+ * frame during this trampoline hop. The stack frame already holds
+ * that of the original caller. _mcount and ftrace_caller will take
+ * care of this TOC value themselves.
+ */
+#define SQUASH_TOC_SAVE_INSN(trampoline_addr) \
+ (((struct ppc64_stub_entry *)(trampoline_addr))->jump[2] = PPC_INST_NOP)
+#else
+#define SQUASH_TOC_SAVE_INSN(trampoline_addr)
+#endif
+
#ifdef CONFIG_DYNAMIC_FTRACE
static u32 ppc64_stub_mask[] = {
0xffff0000,
0xffff0000,
- 0xffffffff,
+ 0x00000000,
0xffffffff,
#if !defined(_CALL_ELF) || _CALL_ELF != 2
0xffffffff,
@@ -170,6 +183,9 @@ bool is_module_trampoline(u32 *p)
if ((insna & mask) != (insnb & mask))
return false;
}
+ if (insns[2] != ppc64_stub_insns[2] &&
+ insns[2] != PPC_INST_NOP)
+ return false;
return true;
}
@@ -618,6 +634,9 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
return -ENOENT;
if (!restore_r2((u32 *)location + 1, me))
return -ENOEXEC;
+ /* Squash the TOC saver for profiler calls */
+ if (!strcmp("_mcount", strtab+sym->st_name))
+ SQUASH_TOC_SAVE_INSN(value);
} else
value += local_entry_offset(sym);
@@ -678,6 +697,10 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
me->arch.tramp = stub_for_addr(sechdrs,
(unsigned long)ftrace_caller,
me);
+ /* ftrace_caller will take care of the TOC;
+ * do not clobber original caller's value.
+ */
+ SQUASH_TOC_SAVE_INSN(me->arch.tramp);
#endif
return 0;
--
1.8.5.6
Convert ppc's arch_ftrace_update_code from its own function copy
to use the generic default functionality (without stop_machine --
our instructions are properly aligned and the replacements atomic ;)
With this we gain error checking and the much-needed function_trace_op
handling.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/kernel/ftrace.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 310137f..e419c7b 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -511,20 +511,12 @@ void ftrace_replace_code(int enable)
}
}
+/* Use the default ftrace_modify_all_code, but without
+ * stop_machine().
+ */
void arch_ftrace_update_code(int command)
{
- if (command & FTRACE_UPDATE_CALLS)
- ftrace_replace_code(1);
- else if (command & FTRACE_DISABLE_CALLS)
- ftrace_replace_code(0);
-
- if (command & FTRACE_UPDATE_TRACE_FUNC)
- ftrace_update_ftrace_func(ftrace_trace_function);
-
- if (command & FTRACE_START_FUNC_RET)
- ftrace_enable_ftrace_graph_caller();
- else if (command & FTRACE_STOP_FUNC_RET)
- ftrace_disable_ftrace_graph_caller();
+ ftrace_modify_all_code(command);
}
int __init ftrace_dyn_arch_init(void)
--
1.8.5.6
* Makefile:
- globally use -mprofile-kernel in case it's configured
and available.
* arch/powerpc/Kconfig / kernel/trace/Kconfig:
- declare that ppc64le HAVE_MPROFILE_KERNEL and
HAVE_DYNAMIC_FTRACE_WITH_REGS, and use it.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/Kconfig | 2 ++
arch/powerpc/Makefile | 10 ++++++++++
kernel/trace/Kconfig | 5 +++++
3 files changed, 17 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index db49e0d..89b1a2a 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -97,8 +97,10 @@ config PPC
select OF_RESERVED_MEM
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_DYNAMIC_FTRACE
+ select HAVE_DYNAMIC_FTRACE_WITH_REGS if PPC64 && CPU_LITTLE_ENDIAN
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_MPROFILE_KERNEL if PPC64 && CPU_LITTLE_ENDIAN
select SYSCTL_EXCEPTION_TRACE
select ARCH_WANT_OPTIONAL_GPIOLIB
select VIRT_TO_BUS if !PPC64
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 96efd82..2f9b527 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -133,6 +133,16 @@ else
CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
endif
+ifeq ($(CONFIG_PPC64),y)
+ifdef CONFIG_HAVE_MPROFILE_KERNEL
+CC_USING_MPROFILE_KERNEL := $(call cc-option,-mprofile-kernel)
+ifdef CC_USING_MPROFILE_KERNEL
+CC_FLAGS_FTRACE := -pg $(CC_USING_MPROFILE_KERNEL)
+KBUILD_CPPFLAGS += -DCC_USING_MPROFILE_KERNEL
+endif
+endif
+endif
+
CFLAGS-$(CONFIG_CELL_CPU) += $(call cc-option,-mcpu=cell)
CFLAGS-$(CONFIG_POWER4_CPU) += $(call cc-option,-mcpu=power4)
CFLAGS-$(CONFIG_POWER5_CPU) += $(call cc-option,-mcpu=power5)
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e45db6b..a138f6d 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -52,6 +52,11 @@ config HAVE_FENTRY
help
Arch supports the gcc options -pg with -mfentry
+config HAVE_MPROFILE_KERNEL
+ bool
+ help
+ Arch supports the gcc options -pg with -mprofile-kernel
+
config HAVE_C_RECORDMCOUNT
bool
help
--
1.8.5.6
Using -mprofile-kernel on early boot code not only confuses the
checker but is also useless, as the infrastructure is not yet in
place. Proceed like with -pg (remove it from CFLAGS), equally with
time.o and ftrace itself.
* arch/powerpc/kernel/Makefile:
- remove -mprofile-kernel from low level and boot code objects'
CFLAGS for FUNCTION_TRACER configurations.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/kernel/Makefile | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index ba33693..0f417d5 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -16,14 +16,14 @@ endif
ifdef CONFIG_FUNCTION_TRACER
# Do not trace early boot code
-CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog
-CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog
-CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog
-CFLAGS_REMOVE_prom.o = -pg -mno-sched-epilog
+CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog -mprofile-kernel
+CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog -mprofile-kernel
+CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog -mprofile-kernel
+CFLAGS_REMOVE_prom.o = -pg -mno-sched-epilog -mprofile-kernel
# do not trace tracer code
-CFLAGS_REMOVE_ftrace.o = -pg -mno-sched-epilog
+CFLAGS_REMOVE_ftrace.o = -pg -mno-sched-epilog -mprofile-kernel
# timers used by tracing
-CFLAGS_REMOVE_time.o = -pg -mno-sched-epilog
+CFLAGS_REMOVE_time.o = -pg -mno-sched-epilog -mprofile-kernel
endif
obj-y := cputable.o ptrace.o syscalls.o \
--
1.8.5.6
At least POWER7/8 have MMUs that don't completely autoload;
a normal, recoverable memory fault might pass through these functions.
If a dynamic tracer function causes such a fault, any of these functions
being traced with -mprofile-kernel may cause an endless recursion.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/kernel/process.c | 2 +-
arch/powerpc/mm/fault.c | 2 +-
arch/powerpc/mm/hash_utils_64.c | 18 +++++++++---------
arch/powerpc/mm/hugetlbpage-hash64.c | 2 +-
arch/powerpc/mm/hugetlbpage.c | 4 ++--
arch/powerpc/mm/mem.c | 2 +-
arch/powerpc/mm/pgtable_64.c | 2 +-
arch/powerpc/mm/slb.c | 6 +++---
arch/powerpc/mm/slice.c | 8 ++++----
9 files changed, 23 insertions(+), 23 deletions(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 646bf4d..5b3c19d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -733,7 +733,7 @@ static inline void __switch_to_tm(struct task_struct *prev)
* don't know which of the checkpointed state and the transactional
* state to use.
*/
-void restore_tm_state(struct pt_regs *regs)
+notrace void restore_tm_state(struct pt_regs *regs)
{
unsigned long msr_diff;
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index a67c6d7..125be37 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -205,7 +205,7 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
* The return value is 0 if the fault was handled, or the signal
* number if this is a kernel fault that can't be handled here.
*/
-int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
+notrace int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
enum ctx_state prev_state = exception_enter();
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 7f9616f..64f5b40 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -849,7 +849,7 @@ void early_init_mmu_secondary(void)
/*
* Called by asm hashtable.S for doing lazy icache flush
*/
-unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
+notrace unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
{
struct page *page;
@@ -870,7 +870,7 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
}
#ifdef CONFIG_PPC_MM_SLICES
-static unsigned int get_paca_psize(unsigned long addr)
+static notrace unsigned int get_paca_psize(unsigned long addr)
{
u64 lpsizes;
unsigned char *hpsizes;
@@ -899,7 +899,7 @@ unsigned int get_paca_psize(unsigned long addr)
* For now this makes the whole process use 4k pages.
*/
#ifdef CONFIG_PPC_64K_PAGES
-void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
+notrace void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
{
if (get_slice_psize(mm, addr) == MMU_PAGE_4K)
return;
@@ -920,7 +920,7 @@ void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
* Result is 0: full permissions, _PAGE_RW: read-only,
* _PAGE_USER or _PAGE_USER|_PAGE_RW: no access.
*/
-static int subpage_protection(struct mm_struct *mm, unsigned long ea)
+static notrace int subpage_protection(struct mm_struct *mm, unsigned long ea)
{
struct subpage_prot_table *spt = &mm->context.spt;
u32 spp = 0;
@@ -968,7 +968,7 @@ void hash_failure_debug(unsigned long ea, unsigned long access,
trap, vsid, ssize, psize, lpsize, pte);
}
-static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
+static notrace void check_paca_psize(unsigned long ea, struct mm_struct *mm,
int psize, bool user_region)
{
if (user_region) {
@@ -990,7 +990,7 @@ static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
* -1 - critical hash insertion error
* -2 - access not permitted by subpage protection mechanism
*/
-int hash_page_mm(struct mm_struct *mm, unsigned long ea,
+notrace int hash_page_mm(struct mm_struct *mm, unsigned long ea,
unsigned long access, unsigned long trap,
unsigned long flags)
{
@@ -1187,7 +1187,7 @@ bail:
}
EXPORT_SYMBOL_GPL(hash_page_mm);
-int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
+notrace int hash_page(unsigned long ea, unsigned long access, unsigned long trap,
unsigned long dsisr)
{
unsigned long flags = 0;
@@ -1289,7 +1289,7 @@ out_exit:
/* WARNING: This is called from hash_low_64.S, if you change this prototype,
* do not forget to update the assembly call site !
*/
-void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
+notrace void flush_hash_page(unsigned long vpn, real_pte_t pte, int psize, int ssize,
unsigned long flags)
{
unsigned long hash, index, shift, hidx, slot;
@@ -1437,7 +1437,7 @@ void low_hash_fault(struct pt_regs *regs, unsigned long address, int rc)
exception_exit(prev_state);
}
-long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
+notrace long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
unsigned long pa, unsigned long rflags,
unsigned long vflags, int psize, int ssize)
{
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index d94b1af..50b8c6f 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -18,7 +18,7 @@ extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn,
unsigned long pa, unsigned long rlags,
unsigned long vflags, int psize, int ssize);
-int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
+notrace int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, unsigned long flags,
int ssize, unsigned int shift, unsigned int mmu_psize)
{
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 9833fee..00c4b03 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -942,7 +942,7 @@ static int __init hugetlbpage_init(void)
#endif
arch_initcall(hugetlbpage_init);
-void flush_dcache_icache_hugepage(struct page *page)
+notrace void flush_dcache_icache_hugepage(struct page *page)
{
int i;
void *start;
@@ -975,7 +975,7 @@ void flush_dcache_icache_hugepage(struct page *page)
* when we have MSR[EE] = 0 but the paca->soft_enabled = 1
*/
-pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+notrace pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
bool *is_thp, unsigned *shift)
{
pgd_t pgd, *pgdp;
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 22d94c3..f690e8a 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -406,7 +406,7 @@ void flush_dcache_page(struct page *page)
}
EXPORT_SYMBOL(flush_dcache_page);
-void flush_dcache_icache_page(struct page *page)
+notrace void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_HUGETLB_PAGE
if (PageCompound(page)) {
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index e92cb21..c74050b 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -442,7 +442,7 @@ static void page_table_free_rcu(void *table)
}
}
-void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
+notrace void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
{
unsigned long pgf = (unsigned long)table;
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index 515730e..3e9be5d 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -96,7 +96,7 @@ static inline void create_shadowed_slbe(unsigned long ea, int ssize,
: "memory" );
}
-static void __slb_flush_and_rebolt(void)
+static notrace void __slb_flush_and_rebolt(void)
{
/* If you change this make sure you change SLB_NUM_BOLTED
* and PR KVM appropriately too. */
@@ -136,7 +136,7 @@ static void __slb_flush_and_rebolt(void)
: "memory");
}
-void slb_flush_and_rebolt(void)
+notrace void slb_flush_and_rebolt(void)
{
WARN_ON(!irqs_disabled());
@@ -151,7 +151,7 @@ void slb_flush_and_rebolt(void)
get_paca()->slb_cache_ptr = 0;
}
-void slb_vmalloc_update(void)
+notrace void slb_vmalloc_update(void)
{
unsigned long vflags;
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 0f432a7..f92f0f0 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -76,8 +76,8 @@ static void slice_print_mask(const char *label, struct slice_mask mask) {}
#endif
-static struct slice_mask slice_range_to_mask(unsigned long start,
- unsigned long len)
+static notrace struct slice_mask slice_range_to_mask(unsigned long start,
+ unsigned long len)
{
unsigned long end = start + len - 1;
struct slice_mask ret = { 0, 0 };
@@ -564,7 +564,7 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
current->mm->context.user_psize, 1);
}
-unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
+notrace unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
{
unsigned char *hpsizes;
int index, mask_index;
@@ -645,7 +645,7 @@ void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
spin_unlock_irqrestore(&slice_convert_lock, flags);
}
-void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
+notrace void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
unsigned long len, unsigned int psize)
{
struct slice_mask mask = slice_range_to_mask(start, len);
--
1.8.5.6
This patch complements the "notrace" attribute for selected functions.
It adds -mprofile-kernel to the cc flags to be stripped from the command
line for code-patching.o and feature-fixups.o, in addition to "-pg"
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/lib/Makefile | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index a47e142..98e22b2 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -6,8 +6,8 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
-CFLAGS_REMOVE_code-patching.o = -pg
-CFLAGS_REMOVE_feature-fixups.o = -pg
+CFLAGS_REMOVE_code-patching.o = -pg -mprofile-kernel
+CFLAGS_REMOVE_feature-fixups.o = -pg -mprofile-kernel
obj-y += string.o alloc.o crtsavres.o ppc_ksyms.o code-patching.o \
feature-fixups.o
--
1.8.5.6
* create the appropriate files+functions
arch/powerpc/include/asm/livepatch.h
klp_check_compiler_support,
klp_arch_set_pc
arch/powerpc/kernel/livepatch.c with a stub for
klp_write_module_reloc
This is architecture-independent work in progress.
* introduce a fixup in arch/powerpc/kernel/entry_64.S
for local calls that are becoming global due to live patching.
And of course do the main KLP thing: return to a maybe different
address, possibly altered by the live patching ftrace op.
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/include/asm/livepatch.h | 45 +++++++++++++++++++++++++++++++
arch/powerpc/kernel/entry_64.S | 51 +++++++++++++++++++++++++++++++++---
arch/powerpc/kernel/livepatch.c | 38 +++++++++++++++++++++++++++
3 files changed, 130 insertions(+), 4 deletions(-)
create mode 100644 arch/powerpc/include/asm/livepatch.h
create mode 100644 arch/powerpc/kernel/livepatch.c
diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h
new file mode 100644
index 0000000..3200c11
--- /dev/null
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -0,0 +1,45 @@
+/*
+ * livepatch.h - powerpc-specific Kernel Live Patching Core
+ *
+ * Copyright (C) 2015 SUSE
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ASM_POWERPC64_LIVEPATCH_H
+#define _ASM_POWERPC64_LIVEPATCH_H
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#ifdef CONFIG_LIVEPATCH
+static inline int klp_check_compiler_support(void)
+{
+#if !defined(_CALL_ELF) || _CALL_ELF != 2 || !defined(CC_USING_MPROFILE_KERNEL)
+ return 1;
+#endif
+ return 0;
+}
+
+extern int klp_write_module_reloc(struct module *mod, unsigned long type,
+ unsigned long loc, unsigned long value);
+
+static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ regs->nip = ip;
+}
+#else
+#error Live patching support is disabled; check CONFIG_LIVEPATCH
+#endif
+
+#endif /* _ASM_POWERPC64_LIVEPATCH_H */
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 294a9ca..09af904 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1265,6 +1265,9 @@ _GLOBAL(ftrace_caller)
mflr r3
std r3, _NIP(r1)
std r3, 16(r1)
+#ifdef CONFIG_LIVEPATCH
+ mr r14,r3 /* remember old NIP */
+#endif
subi r3, r3, MCOUNT_INSN_SIZE
mfmsr r4
std r4, _MSR(r1)
@@ -1281,7 +1284,10 @@ ftrace_call:
nop
ld r3, _NIP(r1)
- mtlr r3
+ mtctr r3 /* prepare to jump there */
+#ifdef CONFIG_LIVEPATCH
+ cmpd r14,r3 /* has NIP been altered? */
+#endif
REST_8GPRS(0,r1)
REST_8GPRS(8,r1)
@@ -1294,6 +1300,27 @@ ftrace_call:
mtlr r12
mr r2,r0 /* restore callee's TOC */
+#ifdef CONFIG_LIVEPATCH
+ beq+ 4f /* likely(old_NIP == new_NIP) */
+
+ /* For a local call, restore this TOC after calling the patch function.
+ * For a global call, it does not matter what we restore here,
+ * since the global caller does its own restore right afterwards,
+ * anyway. Just insert a KLP_return_helper frame in any case,
+ * so a patch function can always count on the changed stack offsets.
+ */
+ stdu r1,-32(r1) /* open new mini stack frame */
+ std r0,24(r1) /* save TOC now, unconditionally. */
+ bl 5f
+5: mflr r12
+ addi r12,r12,(KLP_return_helper+4-.)@l
+ std r12,LRSAVE(r1)
+ mtlr r12
+ mfctr r12 /* allow for TOC calculation in newfunc */
+ bctr
+4:
+#endif
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
stdu r1, -112(r1)
.globl ftrace_graph_call
@@ -1303,15 +1330,31 @@ _GLOBAL(ftrace_graph_stub)
addi r1, r1, 112
#endif
- mflr r0 /* move this LR to CTR */
- mtctr r0
-
ld r0,LRSAVE(r1) /* restore callee's lr at _mcount site */
mtlr r0
bctr /* jump after _mcount site */
#endif /* CC_USING_MPROFILE_KERNEL */
_GLOBAL(ftrace_stub)
blr
+
+#ifdef CONFIG_LIVEPATCH
+/* Helper function for local calls that are becoming global
+ due to live patching.
+ We can't simply patch the NOP after the original call,
+ because, depending on the consistency model, some kernel
+ threads may still have called the original, local function
+ *without* saving their TOC in the respective stack frame slot,
+ so the decision is made per-thread during function return by
+ maybe inserting a KLP_return_helper frame or not.
+*/
+KLP_return_helper:
+ ld r2,24(r1) /* restore TOC (saved by ftrace_caller) */
+ addi r1, r1, 32 /* destroy mini stack frame */
+ ld r0,LRSAVE(r1) /* get the real return address */
+ mtlr r0
+ blr
+#endif
+
#else
_GLOBAL_TOC(_mcount)
/* Taken from output of objdump from lib64/glibc */
diff --git a/arch/powerpc/kernel/livepatch.c b/arch/powerpc/kernel/livepatch.c
new file mode 100644
index 0000000..564eafa
--- /dev/null
+++ b/arch/powerpc/kernel/livepatch.c
@@ -0,0 +1,38 @@
+/*
+ * livepatch.c - powerpc-specific Kernel Live Patching Core
+ *
+ * Copyright (C) 2015 SUSE
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/module.h>
+#include <asm/livepatch.h>
+
+/**
+ * klp_write_module_reloc() - write a relocation in a module
+ * @mod: module in which the section to be modified is found
+ * @type: ELF relocation type (see asm/elf.h)
+ * @loc: address that the relocation should be written to
+ * @value: relocation value (sym address + addend)
+ *
+ * This function writes a relocation to the specified location for
+ * a particular module.
+ */
+int klp_write_module_reloc(struct module *mod, unsigned long type,
+ unsigned long loc, unsigned long value)
+{
+ /* This requires infrastructure changes; we need the loadinfos. */
+ pr_err("lpc_write_module_reloc not yet supported\n");
+ return -ENOSYS;
+}
--
1.8.5.6
Signed-off-by: Torsten Duwe <[email protected]>
---
arch/powerpc/Kconfig | 5 +++++
arch/powerpc/kernel/Makefile | 1 +
2 files changed, 6 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 89b1a2a..62a3f54 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -163,6 +163,9 @@ config PPC
select ARCH_HAS_DMA_SET_COHERENT_MASK
select HAVE_ARCH_SECCOMP_FILTER
+config HAVE_LIVEPATCH
+ def_bool PPC64 && CPU_LITTLE_ENDIAN
+
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
@@ -1095,3 +1098,5 @@ config PPC_LIB_RHEAP
bool
source "arch/powerpc/kvm/Kconfig"
+
+source "kernel/livepatch/Kconfig"
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 0f417d5..f9a2925 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_TRACING) += trace_clock.o
+obj-$(CONFIG_LIVEPATCH) += livepatch.o
ifneq ($(CONFIG_PPC_INDIRECT_PIO),y)
obj-y += iomap.o
--
1.8.5.6