11 files changed, 46 insertions, 83 deletions

diff --git a/arch/powerpc/include/asm/perf_event.h b/arch/powerpc/include/asm/perf_event.h
index e6d4ce69b126..5c16b891d501 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 22e507c8a556..2d29752cbe16 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -127,29 +127,3 @@ _GLOBAL(__setup_cpu_power7)
 _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 7e2669894ce8..74c4e0cd889c 100644
--- a/arch/sparc/include/asm/perf_event.h
+++ b/arch/sparc/include/asm/perf_event.h
@@ -6,7 +6,15 @@ extern void set_perf_event_pending(void);
 #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 92090cc9e829..682fee06a16b 100644
--- a/arch/sparc/kernel/helpers.S
+++ b/arch/sparc/kernel/helpers.S
@@ -47,9 +47,9 @@ stack_trace_flush:
         .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 254883d0c7e0..02de29830ffe 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_instruction_pointer(struct pt_regs *regs);
 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 a957463d3c7a..2b16a2ad23dc 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -78,17 +78,14 @@ struct stack_frame_ia32 {
     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 9632fb61e8f9..2c075fe573d0 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1706,22 +1706,6 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
         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;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index fb6c91eac7e3..bea785cef493 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -905,8 +905,10 @@ extern atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
 
 extern void __perf_sw_event(u32, u64, int, struct pt_regs *, u64);
 
-extern void
-perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
+#ifndef perf_arch_fetch_caller_regs
+static inline void
+perf_arch_fetch_caller_regs(struct regs *regs, unsigned long ip) { }
+#endif
 
 /*
  * Take a snapshot of the regs. Skip ip and frame pointer to
@@ -916,31 +918,11 @@ perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
  * - bp for callchains
  * - eflags, for future purposes, just in case
  */
-static inline void perf_fetch_caller_regs(struct pt_regs *regs, int skip)
+static inline void perf_fetch_caller_regs(struct pt_regs *regs)
 {
-        unsigned long ip;
-
         memset(regs, 0, sizeof(*regs));
 
-        switch (skip) {
-        case 1 :
-                ip = CALLER_ADDR0;
-                break;
-        case 2 :
-                ip = CALLER_ADDR1;
-                break;
-        case 3 :
-                ip = CALLER_ADDR2;
-                break;
-        case 4:
-                ip = CALLER_ADDR3;
-                break;
-        /* No need to support further for now */
-        default:
-                ip = 0;
-        }
-
-        return perf_arch_fetch_caller_regs(regs, ip, skip);
+        perf_arch_fetch_caller_regs(regs, CALLER_ADDR0);
 }
 
 static inline void
@@ -950,7 +932,7 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
                 struct pt_regs hot_regs;
 
                 if (!regs) {
-                        perf_fetch_caller_regs(&hot_regs, 1);
+                        perf_fetch_caller_regs(&hot_regs);
                         regs = &hot_regs;
                 }
                 __perf_sw_event(event_id, nr, nmi, regs, addr);
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 3d685d1f2a03..8ee8b6e6b25e 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -705,7 +705,7 @@ perf_trace_##call(void *__data, proto)					\
         int __data_size;                                                \
         int rctx;                                                       \
                                                                         \
-        perf_fetch_caller_regs(&__regs, 1);                             \
+        perf_fetch_caller_regs(&__regs);                                \
                                                                         \
         __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
         __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index e099650cd249..9ae4dbcdf469 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -2851,11 +2851,6 @@ __weak struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
         return NULL;
 }
 
-__weak
-void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip)
-{
-}
-
 
 /*
  * We assume there is only KVM supporting the callbacks.
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index cb6f365016e4..21db1d3a48d0 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -9,8 +9,6 @@
 #include <linux/kprobes.h>
 #include "trace.h"
 
-EXPORT_SYMBOL_GPL(perf_arch_fetch_caller_regs);
-
 static char *perf_trace_buf[4];
 
 /*