perf: Drop the skip argument from perf_arch_fetch_regs_caller
Drop this argument now that we always want to rewind only to the
state of the first caller.
It means frame pointers are not necessary anymore to reliably get
the source of an event. But this also means we need this helper
to be a macro now, as an inline function is not an option since
we need to know when to provide a default implentation.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/arch/powerpc/include/asm/perf_event.h b/arch/powerpc/include/asm/perf_event.h
index e6d4ce6..5c16b89 100644
--- a/arch/powerpc/include/asm/perf_event.h
+++ b/arch/powerpc/include/asm/perf_event.h
@@ -21,3 +21,15 @@
#ifdef CONFIG_FSL_EMB_PERF_EVENT
#include <asm/perf_event_fsl_emb.h>
#endif
+
+#ifdef CONFIG_PERF_EVENTS
+#include <asm/ptrace.h>
+#include <asm/reg.h>
+
+#define perf_arch_fetch_caller_regs(regs, __ip) \
+ do { \
+ (regs)->nip = __ip; \
+ (regs)->gpr[1] = *(unsigned long *)__get_SP(); \
+ asm volatile("mfmsr %0" : "=r" ((regs)->msr)); \
+ } while (0)
+#endif
diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S
index 22e507c..2d29752 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -127,29 +127,3 @@
_GLOBAL(__restore_cpu_power7)
/* place holder */
blr
-
-/*
- * Get a minimal set of registers for our caller's nth caller.
- * r3 = regs pointer, r5 = n.
- *
- * We only get R1 (stack pointer), NIP (next instruction pointer)
- * and LR (link register). These are all we can get in the
- * general case without doing complicated stack unwinding, but
- * fortunately they are enough to do a stack backtrace, which
- * is all we need them for.
- */
-_GLOBAL(perf_arch_fetch_caller_regs)
- mr r6,r1
- cmpwi r5,0
- mflr r4
- ble 2f
- mtctr r5
-1: PPC_LL r6,0(r6)
- bdnz 1b
- PPC_LL r4,PPC_LR_STKOFF(r6)
-2: PPC_LL r7,0(r6)
- PPC_LL r7,PPC_LR_STKOFF(r7)
- PPC_STL r6,GPR1-STACK_FRAME_OVERHEAD(r3)
- PPC_STL r4,_NIP-STACK_FRAME_OVERHEAD(r3)
- PPC_STL r7,_LINK-STACK_FRAME_OVERHEAD(r3)
- blr
diff --git a/arch/sparc/include/asm/perf_event.h b/arch/sparc/include/asm/perf_event.h
index 7e26698..74c4e0c 100644
--- a/arch/sparc/include/asm/perf_event.h
+++ b/arch/sparc/include/asm/perf_event.h
@@ -6,7 +6,15 @@
#define PERF_EVENT_INDEX_OFFSET 0
#ifdef CONFIG_PERF_EVENTS
+#include <asm/ptrace.h>
+
extern void init_hw_perf_events(void);
+
+extern void
+__perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
+
+#define perf_arch_fetch_caller_regs(pt_regs, ip) \
+ __perf_arch_fetch_caller_regs(pt_regs, ip, 1);
#else
static inline void init_hw_perf_events(void) { }
#endif
diff --git a/arch/sparc/kernel/helpers.S b/arch/sparc/kernel/helpers.S
index 92090cc..682fee0 100644
--- a/arch/sparc/kernel/helpers.S
+++ b/arch/sparc/kernel/helpers.S
@@ -47,9 +47,9 @@
.size stack_trace_flush,.-stack_trace_flush
#ifdef CONFIG_PERF_EVENTS
- .globl perf_arch_fetch_caller_regs
- .type perf_arch_fetch_caller_regs,#function
-perf_arch_fetch_caller_regs:
+ .globl __perf_arch_fetch_caller_regs
+ .type __perf_arch_fetch_caller_regs,#function
+__perf_arch_fetch_caller_regs:
/* We always read the %pstate into %o5 since we will use
* that to construct a fake %tstate to store into the regs.
*/
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 254883d..02de298 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -140,6 +140,19 @@
extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
+#include <asm/stacktrace.h>
+
+/*
+ * We abuse bit 3 from flags to pass exact information, see perf_misc_flags
+ * and the comment with PERF_EFLAGS_EXACT.
+ */
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+ (regs)->ip = (__ip); \
+ (regs)->bp = caller_frame_pointer(); \
+ (regs)->cs = __KERNEL_CS; \
+ regs->flags = 0; \
+}
+
#else
static inline void init_hw_perf_events(void) { }
static inline void perf_events_lapic_init(void) { }
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index a957463..2b16a2a 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -78,17 +78,14 @@
u32 return_address;
};
-static inline unsigned long rewind_frame_pointer(int n)
+static inline unsigned long caller_frame_pointer(void)
{
struct stack_frame *frame;
get_bp(frame);
#ifdef CONFIG_FRAME_POINTER
- while (n--) {
- if (probe_kernel_address(&frame->next_frame, frame))
- break;
- }
+ frame = frame->next_frame;
#endif
return (unsigned long)frame;
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 9632fb6..2c075fe 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1706,22 +1706,6 @@
return entry;
}
-void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
-{
- regs->ip = ip;
- /*
- * perf_arch_fetch_caller_regs adds another call, we need to increment
- * the skip level
- */
- regs->bp = rewind_frame_pointer(skip + 1);
- regs->cs = __KERNEL_CS;
- /*
- * We abuse bit 3 to pass exact information, see perf_misc_flags
- * and the comment with PERF_EFLAGS_EXACT.
- */
- regs->flags = 0;
-}
-
unsigned long perf_instruction_pointer(struct pt_regs *regs)
{
unsigned long ip;
