[PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation
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:
- enhance _mcount with a stub to test (ftrace_trace_function ==
&ftrace_stub)
as suggested in Documentation/trace/ftrace-design.txt
(for reference only, patched out at runtime)
- 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 ELV ABI v2, especially calls to _mcount
that result from gcc -mprofile-kernel
* 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
--
arch/powerpc/include/asm/ftrace.h |5 +
arch/powerpc/kernel/entry_64.S| 112 +++---
arch/powerpc/kernel/ftrace.c | 67 --
arch/powerpc/kernel/module_64.c | 33 ++-
4 files changed, 186 insertions(+), 31 deletions(-)
--
diff --git a/arch/powerpc/include/asm/ftrace.h
b/arch/powerpc/include/asm/ftrace.h
index e366187..691 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+8)
+# 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
+#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 d180caf..a4132ef 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1152,32 +1152,107 @@ _GLOBAL(enter_prom)
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
-_GLOBAL(mcount)
+
+#define TOCSAVE 24
+
_GLOBAL(_mcount)
- blr
+ nop // REQUIRED for ftrace, to calculate local/global entry diff
+.localentry _mcount,.-_mcount
+ mflrr0
+ mtctr r0
+
+ LOAD_REG_ADDR_PIC(r12,ftrace_trace_function)
+ ld r12,0(r12)
+ LOAD_REG_ADDR_PIC(r0,ftrace_stub)
+ cmpdr0,r12
+ ld r0,LRSAVE(r1)
+ bne-2f
+
+ mtlrr0
+ bctr
+
+2: /* here we have (*ftrace_trace_function)() in r12,
+ "selfpc" in CTR
+ and "frompc" in r0 */
+
+ mtlrr0
+ bctr
+
+_GLOBAL(ftrace_caller)
+ mr r0,r2 // global (module) call: save module TOC
+ b 1f
+.localentry ftrace_caller,.-ftrace_caller
+ mr r0,r2 // local call: callee's TOC == our TOC
+ b 2f
+
+1: addis r2,r12,(.TOC.-0b)@ha
+ addir2,r2,(.TOC.-0b)@l
+
+2: // Here we have our proper TOC ptr in R2,
+ // and the one we need to restore on return in r0.
+
+ ld r12, 16(r1) // get caller's adress
+
+ stdur1,-SWITCH_FRAME_SIZE(r1)
+
+ std r12, _LINK(r1)
+ SAVE_8GPRS(0,r1)
+ std r0,TOCSAVE(r1)
+ SAVE_8GPRS(8,r1)
+ SAVE_8GPRS(16,r1)
+ SAVE_8GPRS(24,r1)
+
+
+ LOAD_REG_IMMEDIATE(r3,function_trace_op)
+ ld r5,0(r3)
+
+ mflrr3
+ std r3, _NIP(r1)
+ std r3, 16(r1)
+ subir3, 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
+ addir6, r1 ,STACK_FRAME_OVERHEAD
-_GLOBAL_TOC(ftrace_caller)
- /* Taken from output of objdump from lib64/glibc */
- mflrr3
- ld r11, 0(r1)
- stdur1, -112(r1)
- std r3, 128(r1)
- ld r4, 16(r11)
- subir3, r3, MCOUNT_INSN_SIZE
.globl ftrace_call
ftrace_call:
bl ftrace_stub
nop
+
+ ld r3, _NIP(r1)
+ mtlrr3
+
+ REST_8GPRS(0,r1)
+ REST_8GPRS(8,r1)
+ REST_8GPRS(16,r1)
+ REST_8GPRS(24,r1)
+
+ addi r1, r1, SWITCH_FRAME_SIZE
+
+ ld r12, 16(r1) // get caller's adress
+ mr r2,r0 // restore callee's TOC
+ mflrr0 // move this LR to CTR
+ mtctr r0
+ mr r0,r12 // restore callee's lr at _mcount site
+ mtlrr0
+ bctr// jump after _mcount site
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
[RESEND PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation
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:
- enhance _mcount with a stub to test (ftrace_trace_function ==
&ftrace_stub)
as suggested in Documentation/trace/ftrace-design.txt
(for reference only, patched out at runtime)
- 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 ELV ABI v2, especially calls to _mcount
that result from gcc -mprofile-kernel
* 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
--
arch/powerpc/include/asm/ftrace.h |5 +
arch/powerpc/kernel/entry_64.S| 112 +++---
arch/powerpc/kernel/ftrace.c | 67 --
arch/powerpc/kernel/module_64.c | 33 ++-
4 files changed, 186 insertions(+), 31 deletions(-)
--
diff --git a/arch/powerpc/include/asm/ftrace.h
b/arch/powerpc/include/asm/ftrace.h
index e366187..691 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+8)
+# 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
+#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 d180caf..a4132ef 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1152,32 +1152,107 @@ _GLOBAL(enter_prom)
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
-_GLOBAL(mcount)
+
+#define TOCSAVE 24
+
_GLOBAL(_mcount)
- blr
+ nop // REQUIRED for ftrace, to calculate local/global entry diff
+.localentry _mcount,.-_mcount
+ mflrr0
+ mtctr r0
+
+ LOAD_REG_ADDR_PIC(r12,ftrace_trace_function)
+ ld r12,0(r12)
+ LOAD_REG_ADDR_PIC(r0,ftrace_stub)
+ cmpdr0,r12
+ ld r0,LRSAVE(r1)
+ bne-2f
+
+ mtlrr0
+ bctr
+
+2: /* here we have (*ftrace_trace_function)() in r12,
+ "selfpc" in CTR
+ and "frompc" in r0 */
+
+ mtlrr0
+ bctr
+
+_GLOBAL(ftrace_caller)
+ mr r0,r2 // global (module) call: save module TOC
+ b 1f
+.localentry ftrace_caller,.-ftrace_caller
+ mr r0,r2 // local call: callee's TOC == our TOC
+ b 2f
+
+1: addis r2,r12,(.TOC.-0b)@ha
+ addir2,r2,(.TOC.-0b)@l
+
+2: // Here we have our proper TOC ptr in R2,
+ // and the one we need to restore on return in r0.
+
+ ld r12, 16(r1) // get caller's adress
+
+ stdur1,-SWITCH_FRAME_SIZE(r1)
+
+ std r12, _LINK(r1)
+ SAVE_8GPRS(0,r1)
+ std r0,TOCSAVE(r1)
+ SAVE_8GPRS(8,r1)
+ SAVE_8GPRS(16,r1)
+ SAVE_8GPRS(24,r1)
+
+
+ LOAD_REG_IMMEDIATE(r3,function_trace_op)
+ ld r5,0(r3)
+
+ mflrr3
+ std r3, _NIP(r1)
+ std r3, 16(r1)
+ subir3, 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
+ addir6, r1 ,STACK_FRAME_OVERHEAD
-_GLOBAL_TOC(ftrace_caller)
- /* Taken from output of objdump from lib64/glibc */
- mflrr3
- ld r11, 0(r1)
- stdur1, -112(r1)
- std r3, 128(r1)
- ld r4, 16(r11)
- subir3, r3, MCOUNT_INSN_SIZE
.globl ftrace_call
ftrace_call:
bl ftrace_stub
nop
+
+ ld r3, _NIP(r1)
+ mtlrr3
+
+ REST_8GPRS(0,r1)
+ REST_8GPRS(8,r1)
+ REST_8GPRS(16,r1)
+ REST_8GPRS(24,r1)
+
+ addi r1, r1, SWITCH_FRAME_SIZE
+
+ ld r12, 16(r1) // get caller's adress
+ mr r2,r0 // restore callee's TOC
+ mflrr0 // move this LR to CTR
+ mtctr r0
+ mr r0,r12 // restore callee's lr at _mcount site
+ mtlrr0
+ bctr// jump after _mcount site
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
Re: [RESEND PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation
On Thu, 18 Jun 2015 18:21:07 +0200 Torsten Duwe wrote: > + > _GLOBAL(ftrace_stub) > + nop > + nop > +.localentry ftrace_stub,.-ftrace_stub You might want to run checkpatch and fix your whitespace errors. -- Steve > blr > #else > _GLOBAL_TOC(_mcount) > @@ -1211,12 +1286,12 @@ _GLOBAL(ftrace_stub) ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [RESEND PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation
On Thu, Jun 18, 2015 at 12:49:00PM -0400, Steven Rostedt wrote: > On Thu, 18 Jun 2015 18:21:07 +0200 > Torsten Duwe wrote: > > > + > > _GLOBAL(ftrace_stub) > > + nop > > + nop > > +.localentry ftrace_stub,.-ftrace_stub > > You might want to run checkpatch and fix your whitespace errors. Right. Will do. Thanks, Torsten ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [RESEND PATCH 1/4] ppc64 FTRACE_WITH_REGS implementation
On Thu, 18 Jun 2015 18:21:07 +0200 Torsten Duwe wrote: > 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: > - enhance _mcount with a stub to test (ftrace_trace_function == > &ftrace_stub) > as suggested in Documentation/trace/ftrace-design.txt > (for reference only, patched out at runtime) > - 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 ELV ABI v2, especially calls to _mcount > that result from gcc -mprofile-kernel > * 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 > -- FYI, the standard notation after the change log is '---' not '--'. That way git will chop off this from the change log. When I did a git am -s on this patch I had: Signed-off-by: Torsten Duwe -- arch/powerpc/include/asm/ftrace.h |5 + arch/powerpc/kernel/entry_64.S| 112 +++--- arch/powerpc/kernel/ftrace.c | 67 -- arch/powerpc/kernel/module_64.c | 33 ++- 4 files changed, 186 insertions(+), 31 deletions(-) -- Signed-off-by: Steven Rostedt -- Steve > arch/powerpc/include/asm/ftrace.h |5 + > arch/powerpc/kernel/entry_64.S| 112 > +++--- > arch/powerpc/kernel/ftrace.c | 67 -- > arch/powerpc/kernel/module_64.c | 33 ++- > 4 files changed, 186 insertions(+), 31 deletions(-) > -- > diff --git a/arch/powerpc/include/asm/ftrace.h > b/arch/powerpc/include/asm/ftrace.h > index e366187..691 100644 > --- a/arch/powerpc/include/asm/ftrace.h > +++ b/arch/powerpc/include/asm/ftrace.h ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
