diff options
Diffstat (limited to 'arch/powerpc/perf/core-book3s.c')
| -rw-r--r-- | arch/powerpc/perf/core-book3s.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index dcb6a798f111..77b49ddda9d3 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -189,9 +189,30 @@ static inline void perf_read_regs(struct pt_regs *regs) int marked = mmcra & MMCRA_SAMPLE_ENABLE; int use_siar; + /* + * If this isn't a PMU exception (eg a software event) the SIAR is + * not valid. Use pt_regs. + * + * If it is a marked event use the SIAR. + * + * If the PMU doesn't update the SIAR for non marked events use + * pt_regs. + * + * If the PMU has HV/PR flags then check to see if they + * place the exception in userspace. If so, use pt_regs. In + * continuous sampling mode the SIAR and the PMU exception are + * not synchronised, so they may be many instructions apart. + * This can result in confusing backtraces. We still want + * hypervisor samples as well as samples in the kernel with + * interrupts off hence the userspace check. + */ if (TRAP(regs) != 0xf00) use_siar = 0; - else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING) && !marked) + else if (marked) + use_siar = 1; + else if ((ppmu->flags & PPMU_NO_CONT_SAMPLING)) + use_siar = 0; + else if (!(ppmu->flags & PPMU_NO_SIPR) && mmcra_sipr(mmcra)) use_siar = 0; else use_siar = 1; |