x86, perf: Disable non available architectural events

Intel CPUs report non-available architectural events in cpuid leaf
0AH.EBX. Use it to disable events that are not available according
to CPU.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1320929850-10480-7-git-send-email-gleb@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 42 insertions, 5 deletions

diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index f61c62f7d5d8..c6998bc75456 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -57,6 +57,7 @@
                 (1 << (ARCH_PERFMON_UNHALTED_CORE_CYCLES_INDEX))
 
 #define ARCH_PERFMON_BRANCH_MISSES_RETIRED              6
+#define ARCH_PERFMON_EVENTS_COUNT                       7
 
 /*
  * Intel "Architectural Performance Monitoring" CPUID
@@ -72,6 +73,19 @@ union cpuid10_eax {
         unsigned int full;
 };
 
+union cpuid10_ebx {
+        struct {
+                unsigned int no_unhalted_core_cycles:1;
+                unsigned int no_instructions_retired:1;
+                unsigned int no_unhalted_reference_cycles:1;
+                unsigned int no_llc_reference:1;
+                unsigned int no_llc_misses:1;
+                unsigned int no_branch_instruction_retired:1;
+                unsigned int no_branch_misses_retired:1;
+        } split;
+        unsigned int full;
+};
+
 union cpuid10_edx {
         struct {
                 unsigned int num_counters_fixed:5;
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 51a985cbc12f..f49c5c21085c 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -285,6 +285,11 @@ struct x86_pmu {
         int             num_counters_fixed;
         int             cntval_bits;
         u64             cntval_mask;
+        union {
+                        unsigned long events_maskl;
+                        unsigned long events_mask[BITS_TO_LONGS(ARCH_PERFMON_EVENTS_COUNT)];
+        };
+        int             events_mask_len;
         int             apic;
         u64             max_period;
         struct event_constraint *
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 8d601b18bf9f..201156b80a37 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1552,13 +1552,23 @@ static void intel_sandybridge_quirks(void)
         x86_pmu.pebs_constraints = NULL;
 }
 
+static const int intel_event_id_to_hw_id[] __initconst = {
+        PERF_COUNT_HW_CPU_CYCLES,
+        PERF_COUNT_HW_INSTRUCTIONS,
+        PERF_COUNT_HW_BUS_CYCLES,
+        PERF_COUNT_HW_CACHE_REFERENCES,
+        PERF_COUNT_HW_CACHE_MISSES,
+        PERF_COUNT_HW_BRANCH_INSTRUCTIONS,
+        PERF_COUNT_HW_BRANCH_MISSES,
+};
+
 __init int intel_pmu_init(void)
 {
         union cpuid10_edx edx;
         union cpuid10_eax eax;
+        union cpuid10_ebx ebx;
         unsigned int unused;
-        unsigned int ebx;
-        int version;
+        int version, bit;
 
         if (!cpu_has(&boot_cpu_data, X86_FEATURE_ARCH_PERFMON)) {
                 switch (boot_cpu_data.x86) {
@@ -1574,8 +1584,8 @@ __init int intel_pmu_init(void)
          * Check whether the Architectural PerfMon supports
          * Branch Misses Retired hw_event or not.
          */
-        cpuid(10, &eax.full, &ebx, &unused, &edx.full);
-        if (eax.split.mask_length <= ARCH_PERFMON_BRANCH_MISSES_RETIRED)
+        cpuid(10, &eax.full, &ebx.full, &unused, &edx.full);
+        if (eax.split.mask_length < ARCH_PERFMON_EVENTS_COUNT)
                 return -ENODEV;
 
         version = eax.split.version_id;
@@ -1651,7 +1661,7 @@ __init int intel_pmu_init(void)
                 /* UOPS_EXECUTED.CORE_ACTIVE_CYCLES,c=1,i=1 */
                 intel_perfmon_event_map[PERF_COUNT_HW_STALLED_CYCLES_BACKEND] = 0x1803fb1;
 
-                if (ebx & 0x40) {
+                if (ebx.split.no_branch_misses_retired) {
                         /*
                          * Erratum AAJ80 detected, we work it around by using
                          * the BR_MISP_EXEC.ANY event. This will over-count
@@ -1659,6 +1669,7 @@ __init int intel_pmu_init(void)
                          * architectural event which is often completely bogus:
                          */
                         intel_perfmon_event_map[PERF_COUNT_HW_BRANCH_MISSES] = 0x7f89;
+                        ebx.split.no_branch_misses_retired = 0;
 
                         pr_cont("erratum AAJ80 worked around, ");
                 }
@@ -1738,5 +1749,12 @@ __init int intel_pmu_init(void)
                         break;
                 }
         }
+        x86_pmu.events_maskl            = ebx.full;
+        x86_pmu.events_mask_len         = eax.split.mask_length;
+
+        /* disable event that reported as not presend by cpuid */
+        for_each_set_bit(bit, x86_pmu.events_mask, ARRAY_SIZE(intel_event_id_to_hw_id))
+                intel_perfmon_event_map[intel_event_id_to_hw_id[bit]] = 0;
+
         return 0;
 }