arm64: perf: don't rely on layout of pt_regs when grabbing sp or pc

The current perf_regs code relies on sp and pc sitting just off the end
of the pt_regs->regs array. This is ugly and fragile, so this patch
checks for these register explicitly and returns the appropriate field.

Acked-by: Jean Pihet <[email protected]>
Signed-off-by: Will Deacon <[email protected]>

diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c
index 422ebd63b619253d23c7a82d5fb14b322dc47fe1..6762ad705587fa34fff0281546273a6930ddbcbf 100644 (file)
--- a/arch/arm64/kernel/perf_regs.c
+++ b/arch/arm64/kernel/perf_regs.c
@@ -24,6 +24,12 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
                        return regs->compat_lr;
        }
 
+       if ((u32)idx == PERF_REG_ARM64_SP)
+               return regs->sp;
+
+       if ((u32)idx == PERF_REG_ARM64_PC)
+               return regs->pc;
+
        return regs->regs[idx];
 }