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Message-Id: <1317912555-9559-6-git-send-email-eranian@google.com>
Date: Thu, 6 Oct 2011 16:49:08 +0200
From: Stephane Eranian <eranian@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: peterz@...radead.org, mingo@...e.hu, acme@...hat.com,
ming.m.lin@...el.com, andi@...stfloor.org, robert.richter@....com,
ravitillo@....gov
Subject: [PATCH 05/12] perf_events: add LBR mappings for PERF_SAMPLE_BRANCH filters
This patch adds the mappings from the generic PERF_SAMPLE_BRANCH_*
filters to the actual Intel X86 LBR filters, whenever they exist.
The patch also adds a restriction on Intel Atom, whereby only
stepping 10 (PineView) and more recent are supported. Older models,
do not have a functional LBR (does not freeze on PMU interrupt).
Signed-off-by: Stephane Eranian <eranian@...gle.com>
---
arch/x86/kernel/cpu/perf_event_intel.c | 2 +-
arch/x86/kernel/cpu/perf_event_intel_lbr.c | 110 +++++++++++++++++++++++++++-
2 files changed, 109 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index e2639f4..740857f 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1612,7 +1612,7 @@ static __init int intel_pmu_init(void)
memcpy(hw_cache_event_ids, snb_hw_cache_event_ids,
sizeof(hw_cache_event_ids));
- intel_pmu_lbr_init_nhm();
+ intel_pmu_lbr_init_snb();
x86_pmu.event_constraints = intel_snb_event_constraints;
x86_pmu.pebs_constraints = intel_snb_pebs_events;
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index e8a6851..abcabe3 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -8,6 +8,47 @@ enum {
};
/*
+ * Intel LBR_SELECT bits
+ * Intel Vol3a, April 2011, Section 16.7 Table 16-10
+ *
+ * Hardware branch filter (not available on all CPUs)
+ */
+#define LBR_KERNEL_BIT 0 /* do not capture at ring0 */
+#define LBR_USER_BIT 1 /* do not capture at ring > 0 */
+#define LBR_JCC_BIT 2 /* do not capture conditional branches */
+#define LBR_REL_CALL_BIT 3 /* do not capture relative calls */
+#define LBR_IND_CALL_BIT 4 /* do not capture indirect calls */
+#define LBR_RETURN_BIT 5 /* do not capture near returns */
+#define LBR_IND_JMP_BIT 6 /* do not capture indirect jumps */
+#define LBR_REL_JMP_BIT 7 /* do not capture relative jumps */
+#define LBR_FAR_BIT 8 /* do not capture far branches */
+
+#define LBR_KERNEL (1 << LBR_KERNEL_BIT)
+#define LBR_USER (1 << LBR_USER_BIT)
+#define LBR_JCC (1 << LBR_JCC_BIT)
+#define LBR_REL_CALL (1 << LBR_REL_CALL_BIT)
+#define LBR_IND_CALL (1 << LBR_IND_CALL_BIT)
+#define LBR_RETURN (1 << LBR_RETURN_BIT)
+#define LBR_REL_JMP (1 << LBR_REL_JMP_BIT)
+#define LBR_IND_JMP (1 << LBR_IND_JMP_BIT)
+#define LBR_FAR (1 << LBR_FAR_BIT)
+
+#define LBR_PLM (LBR_KERNEL | LBR_USER)
+
+#define LBR_SEL_MASK 0x1ff /* valid bits in LBR_SELECT */
+
+#define LBR_ANY \
+ (LBR_JCC |\
+ LBR_REL_CALL |\
+ LBR_IND_CALL |\
+ LBR_RETURN |\
+ LBR_REL_JMP |\
+ LBR_IND_JMP |\
+ LBR_FAR)
+
+#define LBR_FROM_FLAG_MISPRED (1ULL << 63)
+
+/*
* We only support LBR implementations that have FREEZE_LBRS_ON_PMI
* otherwise it becomes near impossible to get a reliable stack.
*/
@@ -147,8 +188,6 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
cpuc->lbr_stack.nr = i;
}
-#define LBR_FROM_FLAG_MISPRED (1ULL << 63)
-
/*
* Due to lack of segmentation in Linux the effective address (offset)
* is the same as the linear address, allowing us to merge the LIP and EIP
@@ -196,28 +235,95 @@ static void intel_pmu_lbr_read(void)
intel_pmu_lbr_read_64(cpuc);
}
+/*
+ * Map interface branch filters onto LBR filters
+ */
+static const int nhm_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX]=
+{
+ [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY,
+ [PERF_SAMPLE_BRANCH_USER] = LBR_USER,
+ [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL,
+ [PERF_SAMPLE_BRANCH_ANY_RETURN] =
+ LBR_RETURN | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR,
+ /*
+ * NHM/WSM erratum: must include REL_JMP+IND_JMP to get CALL branches
+ */
+ [PERF_SAMPLE_BRANCH_ANY_CALL] =
+ LBR_REL_CALL | LBR_IND_CALL | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR,
+ /*
+ * NHM/WSM erratum: must include IND_JMP to capture IND_CALL
+ */
+ [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL | LBR_IND_JMP,
+};
+
+static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX]=
+{
+ [PERF_SAMPLE_BRANCH_ANY] = LBR_ANY,
+ [PERF_SAMPLE_BRANCH_USER] = LBR_USER,
+ [PERF_SAMPLE_BRANCH_KERNEL] = LBR_KERNEL,
+ [PERF_SAMPLE_BRANCH_ANY_RETURN] = LBR_RETURN | LBR_FAR,
+ [PERF_SAMPLE_BRANCH_ANY_CALL] = LBR_REL_CALL | LBR_IND_CALL | LBR_FAR,
+ [PERF_SAMPLE_BRANCH_IND_CALL] = LBR_IND_CALL,
+};
+
+/* core */
static void intel_pmu_lbr_init_core(void)
{
x86_pmu.lbr_nr = 4;
x86_pmu.lbr_tos = MSR_LBR_TOS;
x86_pmu.lbr_from = MSR_LBR_CORE_FROM;
x86_pmu.lbr_to = MSR_LBR_CORE_TO;
+
+ pr_cont("4-deep LBR, ");
}
+/* nehalem/westmere */
static void intel_pmu_lbr_init_nhm(void)
{
x86_pmu.lbr_nr = 16;
x86_pmu.lbr_tos = MSR_LBR_TOS;
x86_pmu.lbr_from = MSR_LBR_NHM_FROM;
x86_pmu.lbr_to = MSR_LBR_NHM_TO;
+
+ x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
+ x86_pmu.lbr_sel_map = nhm_lbr_sel_map;
+
+ pr_cont("16-deep LBR, ");
+}
+
+/* sandy bridge */
+static void intel_pmu_lbr_init_snb(void)
+{
+ x86_pmu.lbr_nr = 16;
+ x86_pmu.lbr_tos = MSR_LBR_TOS;
+ x86_pmu.lbr_from = MSR_LBR_NHM_FROM;
+ x86_pmu.lbr_to = MSR_LBR_NHM_TO;
+
+ x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
+ x86_pmu.lbr_sel_map = snb_lbr_sel_map;
+
+ pr_cont("16-deep LBR, ");
}
+/* atom */
static void intel_pmu_lbr_init_atom(void)
{
+ /*
+ * only models starting at stepping 10 seems
+ * to have an operational LBR which can freeze
+ * on PMU interrupt
+ */
+ if (boot_cpu_data.x86_mask < 10) {
+ pr_cont("LBR disabled due to erratum");
+ return;
+ }
+
x86_pmu.lbr_nr = 8;
x86_pmu.lbr_tos = MSR_LBR_TOS;
x86_pmu.lbr_from = MSR_LBR_CORE_FROM;
x86_pmu.lbr_to = MSR_LBR_CORE_TO;
+
+ pr_cont("8-deep LBR, ");
}
#endif /* CONFIG_CPU_SUP_INTEL */
--
1.7.4.1
--
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