From: David Miller on

After b0f82b81fe6bbcf78d478071f33e44554726bc81 ("perf: Drop the skip
argument from perf_arch_fetch_regs_caller") the build broke on sparc64
due to the lack of a module symbol export of __perf_arch_fetch_caller_regs.

But that assembler helper can actually be complete eliminated now that
the semantics of this interface have been greatly simplified.

Signed-off-by: David S. Miller <davem(a)davemloft.net>
---

Frederic, I'll merge this to Linus via the sparc tree, this is
just FYI...

arch/sparc/include/asm/perf_event.h | 25 +++++++++--
arch/sparc/kernel/helpers.S | 75 -----------------------------------
2 files changed, 20 insertions(+), 80 deletions(-)

diff --git a/arch/sparc/include/asm/perf_event.h b/arch/sparc/include/asm/perf_event.h
index 74c4e0c..727af70 100644
--- a/arch/sparc/include/asm/perf_event.h
+++ b/arch/sparc/include/asm/perf_event.h
@@ -10,11 +10,26 @@ extern void set_perf_event_pending(void);

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);
+#define perf_arch_fetch_caller_regs(regs, ip) \
+do { \
+ unsigned long _pstate, _asi, _pil, _i7, _fp; \
+ __asm__ __volatile__("rdpr %%pstate, %0\n\t" \
+ "rd %%asi, %1\n\t" \
+ "rdpr %%pil, %2\n\t" \
+ "mov %%i7, %3\n\t" \
+ "mov %%i6, %4\n\t" \
+ : "=r" (_pstate), \
+ "=r" (_asi), \
+ "=r" (_pil), \
+ "=r" (_i7), \
+ "=r" (_fp)); \
+ (regs)->tstate = (_pstate << 8) | \
+ (_asi << 24) | (_pil << 20); \
+ (regs)->tpc = (ip); \
+ (regs)->tnpc = (regs)->tpc + 4; \
+ (regs)->u_regs[UREG_I6] = _fp; \
+ (regs)->u_regs[UREG_I7] = _i7; \
+} while (0)
#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 682fee0..314dd0c 100644
--- a/arch/sparc/kernel/helpers.S
+++ b/arch/sparc/kernel/helpers.S
@@ -46,81 +46,6 @@ stack_trace_flush:
nop
.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:
- /* We always read the %pstate into %o5 since we will use
- * that to construct a fake %tstate to store into the regs.
- */
- rdpr %pstate, %o5
- brz,pn %o2, 50f
- mov %o2, %g7
-
- /* Turn off interrupts while we walk around the register
- * window by hand.
- */
- wrpr %o5, PSTATE_IE, %pstate
-
- /* The %canrestore tells us how many register windows are
- * still live in the chip above us, past that we have to
- * walk the frame as saved on the stack. We stash away
- * the %cwp in %g1 so we can return back to the original
- * register window.
- */
- rdpr %cwp, %g1
- rdpr %canrestore, %g2
- sub %g1, 1, %g3
-
- /* We have the skip count in %g7, if it hits zero then
- * %fp/%i7 are the registers we need. Otherwise if our
- * %canrestore count maintained in %g2 hits zero we have
- * to start traversing the stack.
- */
-10: brz,pn %g2, 4f
- sub %g2, 1, %g2
- wrpr %g3, %cwp
- subcc %g7, 1, %g7
- bne,pt %xcc, 10b
- sub %g3, 1, %g3
-
- /* We found the values we need in the cpu's register
- * windows.
- */
- mov %fp, %g3
- ba,pt %xcc, 3f
- mov %i7, %g2
-
-50: mov %fp, %g3
- ba,pt %xcc, 2f
- mov %i7, %g2
-
- /* We hit the end of the valid register windows in the
- * cpu, start traversing the stack frame.
- */
-4: mov %fp, %g3
-
-20: ldx [%g3 + STACK_BIAS + RW_V9_I7], %g2
- subcc %g7, 1, %g7
- bne,pn %xcc, 20b
- ldx [%g3 + STACK_BIAS + RW_V9_I6], %g3
-
- /* Restore the current register window position and
- * re-enable interrupts.
- */
-3: wrpr %g1, %cwp
- wrpr %o5, %pstate
-
-2: stx %g3, [%o0 + PT_V9_FP]
- sllx %o5, 8, %o5
- stx %o5, [%o0 + PT_V9_TSTATE]
- stx %g2, [%o0 + PT_V9_TPC]
- add %g2, 4, %g2
- retl
- stx %g2, [%o0 + PT_V9_TNPC]
- .size perf_arch_fetch_caller_regs,.-perf_arch_fetch_caller_regs
-#endif /* CONFIG_PERF_EVENTS */
-
#ifdef CONFIG_SMP
.globl hard_smp_processor_id
.type hard_smp_processor_id,#function
--
1.7.2.1

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