sparc64: Fix perf_arch_get_caller_regs().

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@davemloft.net>

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 74c4e0cd889..727af70646c 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 682fee06a16..314dd0c9fc5 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