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authorKan Liang <kan.liang@intel.com>2016-04-21 02:30:10 -0700
committerIngo Molnar <mingo@kernel.org>2016-04-28 10:32:43 +0200
commitcf3beb7c90a8efa16a06b26634cddddc92bb819c (patch)
tree8cb7d0af1c321b95254c0371cf1fbc4c6f473894 /arch/x86/events/intel
parent1c5ac21a0e9bab7fc45d0ba9e11623e9ad99d02e (diff)
perf/x86/intel: Fix incorrect lbr_sel_mask value
This patch fixes a bug which was introduced by: b16a5b52eb90 ("perf/x86: Add option to disable reading branch flags/cycles") In this patch, lbr_sel_mask is used to mask the lbr_select. But LBR_SEL_MASK doesn't include the bit for LBR_CALL_STACK. So LBR call stack will never be set in lbr_select. This patch corrects the LBR_SEL_MASK by including all valid bits in LBR_SELECT. Also, the LBR_CALL_STACK bit is different as other bit in LBR_SELECT. It does not operate in suppress mode, so it needs to be specially handled in intel_pmu_setup_hw_lbr_filter. Signed-off-by: Kan Liang <kan.liang@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1461231010-4399-1-git-send-email-kan.liang@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/events/intel')
-rw-r--r--arch/x86/events/intel/lbr.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 6c3b7c1780c9..1ca5d1e7d4f2 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -63,7 +63,7 @@ static enum {
#define LBR_PLM (LBR_KERNEL | LBR_USER)
-#define LBR_SEL_MASK 0x1ff /* valid bits in LBR_SELECT */
+#define LBR_SEL_MASK 0x3ff /* valid bits in LBR_SELECT */
#define LBR_NOT_SUPP -1 /* LBR filter not supported */
#define LBR_IGN 0 /* ignored */
@@ -610,8 +610,10 @@ static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event)
* The first 9 bits (LBR_SEL_MASK) in LBR_SELECT operate
* in suppress mode. So LBR_SELECT should be set to
* (~mask & LBR_SEL_MASK) | (mask & ~LBR_SEL_MASK)
+ * But the 10th bit LBR_CALL_STACK does not operate
+ * in suppress mode.
*/
- reg->config = mask ^ x86_pmu.lbr_sel_mask;
+ reg->config = mask ^ (x86_pmu.lbr_sel_mask & ~LBR_CALL_STACK);
if ((br_type & PERF_SAMPLE_BRANCH_NO_CYCLES) &&
(br_type & PERF_SAMPLE_BRANCH_NO_FLAGS) &&