[PATCH 2/4] perf/x86: add support for PERF_SAMPLE_BRANCH_CALL

Stephane Eranian
2015-10-13T07:10:59Z

This patch enables the suport for the PERF_SAMPLE_BRANCH_CALL
for Intel x86 processors. When the processor support LBR filtering
this the selection is done in hardware. Otherwise, the filter is
applied by software. Note that we chose to include zero length calls
because they also represent calls.

Signed-off-by: Stephane Eranian <eranian@google.com>
---
arch/x86/kernel/cpu/perf_event_intel_lbr.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index ad0b8b0..bfd0b71 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -555,6 +555,8 @@ static int intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
if (br_type & PERF_SAMPLE_BRANCH_IND_JUMP)
mask |= X86_BR_IND_JMP;

+ if (br_type & PERF_SAMPLE_BRANCH_CALL)
+ mask |= X86_BR_CALL | X86_BR_ZERO_CALL;
/*
* stash actual user request into reg, it may
* be used by fixup code for some CPU
@@ -890,6 +892,7 @@ static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
[PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_IND_CALL,
[PERF_SAMPLE_BRANCH_COND_SHIFT] = LBR_JCC,
[PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT] = LBR_IND_JMP,
+ [PERF_SAMPLE_BRANCH_CALL_SHIFT] = LBR_REL_CALL,
};

static const int hsw_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
@@ -905,6 +908,7 @@ static const int hsw_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
[PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT] = LBR_REL_CALL | LBR_IND_CALL
| LBR_RETURN | LBR_CALL_STACK,
[PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT] = LBR_IND_JMP,
+ [PERF_SAMPLE_BRANCH_CALL_SHIFT] = LBR_REL_CALL,
};

/* core */
--
1.9.1