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-rw-r--r--arch/sparc/kernel/helpers.S75
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/sparc/kernel/helpers.S b/arch/sparc/kernel/helpers.S
index 314dd0c9fc5..92090cc9e82 100644
--- a/arch/sparc/kernel/helpers.S
+++ b/arch/sparc/kernel/helpers.S
@@ -46,6 +46,81 @@ 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