[PATCH v6 2/6] perf/x86: add support for sampling PEBS machine state registers

From: Stephane Eranian
Date: Tue Sep 23 2014 - 10:58:40 EST


PEBS can capture machine state regs at retiremnt of the sampled
instructions. When precise sampling is enabled on an event, PEBS
is used, so substitute the interrupted state with the PEBS state.
Note that not all registers are captured by PEBS. Those missing
are replaced by the interrupt state counter-parts.

Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_intel_ds.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index b1553d0..0318023 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -886,6 +886,28 @@ static void __intel_pmu_pebs_event(struct perf_event *event,
regs.bp = pebs->bp;
regs.sp = pebs->sp;

+ if (sample_type & PERF_SAMPLE_REGS_INTR) {
+ regs.ax = pebs->ax;
+ regs.bx = pebs->bx;
+ regs.cx = pebs->cx;
+ regs.dx = pebs->dx;
+ regs.si = pebs->si;
+ regs.di = pebs->di;
+ regs.sp = pebs->sp;
+ regs.bp = pebs->bp;
+
+ regs.eflags = pebs->flags;
+
+ regs.r8 = pebs->r8;
+ regs.r9 = pebs->r9;
+ regs.r10 = pebs->r10;
+ regs.r11 = pebs->r11;
+ regs.r12 = pebs->r12;
+ regs.r13 = pebs->r13;
+ regs.r14 = pebs->r14;
+ regs.r15 = pebs->r15;
+ }
+
if (event->attr.precise_ip > 1 && x86_pmu.intel_cap.pebs_format >= 2) {
regs.ip = pebs->real_ip;
regs.flags |= PERF_EFLAGS_EXACT;
--
1.7.9.5

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