diff options
Diffstat (limited to 'arch/x86/events/intel/ds.c')
| -rw-r--r-- | arch/x86/events/intel/ds.c | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 9b983a474..8fc714b4f 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -1070,20 +1070,20 @@ static void setup_pebs_sample_data(struct perf_event *event, } /* - * We use the interrupt regs as a base because the PEBS record - * does not contain a full regs set, specifically it seems to - * lack segment descriptors, which get used by things like - * user_mode(). + * We use the interrupt regs as a base because the PEBS record does not + * contain a full regs set, specifically it seems to lack segment + * descriptors, which get used by things like user_mode(). * - * In the simple case fix up only the IP and BP,SP regs, for - * PERF_SAMPLE_IP and PERF_SAMPLE_CALLCHAIN to function properly. - * A possible PERF_SAMPLE_REGS will have to transfer all regs. + * In the simple case fix up only the IP for PERF_SAMPLE_IP. + * + * We must however always use BP,SP from iregs for the unwinder to stay + * sane; the record BP,SP can point into thin air when the record is + * from a previous PMI context or an (I)RET happend between the record + * and PMI. */ *regs = *iregs; regs->flags = pebs->flags; set_linear_ip(regs, pebs->ip); - regs->bp = pebs->bp; - regs->sp = pebs->sp; if (sample_type & PERF_SAMPLE_REGS_INTR) { regs->ax = pebs->ax; @@ -1092,10 +1092,21 @@ static void setup_pebs_sample_data(struct perf_event *event, regs->dx = pebs->dx; regs->si = pebs->si; regs->di = pebs->di; - regs->bp = pebs->bp; - regs->sp = pebs->sp; - regs->flags = pebs->flags; + /* + * Per the above; only set BP,SP if we don't need callchains. + * + * XXX: does this make sense? + */ + if (!(sample_type & PERF_SAMPLE_CALLCHAIN)) { + regs->bp = pebs->bp; + regs->sp = pebs->sp; + } + + /* + * Preserve PERF_EFLAGS_VM from set_linear_ip(). + */ + regs->flags = pebs->flags | (regs->flags & PERF_EFLAGS_VM); #ifndef CONFIG_X86_32 regs->r8 = pebs->r8; regs->r9 = pebs->r9; |