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Subject[PATCH] arm64: perf: Report arm pc registers for compat perf
Date
If perf is built as arm 32-bit, it only reads 15 registers as arm
32-bit register map and this breaks dwarf call-chain in compat
perf because pc register information is not filled.
Report arm pc registers for 32-bit compat perf.

Without this, arm 32-bit perf dwarf call-graph shows below
verbose message:
unwind: reg 15, val 0
unwind: reg 13, val ffbc6360
unwind: no map for 0

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
---
arch/arm64/kernel/perf_regs.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c
index 0bbac61..d4172e7 100644
--- a/arch/arm64/kernel/perf_regs.c
+++ b/arch/arm64/kernel/perf_regs.c
@@ -24,6 +24,8 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
return regs->compat_sp;
if ((u32)idx == PERF_REG_ARM64_LR)
return regs->compat_lr;
+ if ((u32)idx == 15) /* PERF_REG_ARM_PC */
+ return regs->pc;
}

if ((u32)idx == PERF_REG_ARM64_SP)
--
1.7.4.1
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