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Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_lbr.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 659f01e165d5..e2fad0cdca2f 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -42,6 +42,13 @@ static enum {
#define LBR_FAR_BIT 8 /* do not capture far branches */
#define LBR_CALL_STACK_BIT 9 /* enable call stack */
+/*
+ * Following bit only exists in Linux; we mask it out before writing it to
+ * the actual MSR. But it helps the constraint perf code to understand
+ * that this is a separate configuration.
+ */
+#define LBR_NO_INFO_BIT 63 /* don't read LBR_INFO. */
+
#define LBR_KERNEL (1 << LBR_KERNEL_BIT)
#define LBR_USER (1 << LBR_USER_BIT)
#define LBR_JCC (1 << LBR_JCC_BIT)
@@ -52,6 +59,7 @@ static enum {
#define LBR_IND_JMP (1 << LBR_IND_JMP_BIT)
#define LBR_FAR (1 << LBR_FAR_BIT)
#define LBR_CALL_STACK (1 << LBR_CALL_STACK_BIT)
+#define LBR_NO_INFO (1ULL << LBR_NO_INFO_BIT)
#define LBR_PLM (LBR_KERNEL | LBR_USER)
@@ -152,7 +160,7 @@ static void __intel_pmu_lbr_enable(bool pmi)
* did not change.
*/
if (cpuc->lbr_sel)
- lbr_select = cpuc->lbr_sel->config;
+ lbr_select = cpuc->lbr_sel->config & x86_pmu.lbr_sel_mask;
if (!pmi)
wrmsrl(MSR_LBR_SELECT, lbr_select);
@@ -422,6 +430,7 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
*/
static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
{
+ bool need_info = !(cpuc->lbr_sel->config & LBR_NO_INFO);
unsigned long mask = x86_pmu.lbr_nr - 1;
int lbr_format = x86_pmu.intel_cap.lbr_format;
u64 tos = intel_pmu_lbr_tos();
@@ -442,7 +451,7 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
rdmsrl(x86_pmu.lbr_from + lbr_idx, from);
rdmsrl(x86_pmu.lbr_to + lbr_idx, to);
- if (lbr_format == LBR_FORMAT_INFO) {
+ if (lbr_format == LBR_FORMAT_INFO && need_info) {
u64 info;
rdmsrl(MSR_LBR_INFO_0 + lbr_idx, info);
@@ -590,6 +599,7 @@ static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event)
if (v != LBR_IGN)
mask |= v;
}
+
reg = &event->hw.branch_reg;
reg->idx = EXTRA_REG_LBR;
@@ -600,6 +610,11 @@ static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event)
*/
reg->config = mask ^ x86_pmu.lbr_sel_mask;
+ if ((br_type & PERF_SAMPLE_BRANCH_NO_CYCLES) &&
+ (br_type & PERF_SAMPLE_BRANCH_NO_FLAGS) &&
+ (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO))
+ reg->config |= LBR_NO_INFO;
+
return 0;
}