Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf, x86, nmi: Move LVT un-masking into irq handlers
  perf events, x86: Work around the Nehalem AAJ80 erratum
  perf, x86: Fix BTS condition
  ftrace: Build without frame pointers on Microblaze

3 files changed, 52 insertions, 10 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 632e5dc9c9c0..e638689279d3 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -613,8 +613,8 @@ static int x86_setup_perfctr(struct perf_event *event)
         /*
          * Branch tracing:
          */
-        if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
-            (hwc->sample_period == 1)) {
+        if (attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS &&
+            !attr->freq && hwc->sample_period == 1) {
                 /* BTS is not supported by this architecture. */
                 if (!x86_pmu.bts_active)
                         return -EOPNOTSUPP;
@@ -1288,6 +1288,16 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
 
         cpuc = &__get_cpu_var(cpu_hw_events);
 
+        /*
+         * Some chipsets need to unmask the LVTPC in a particular spot
+         * inside the nmi handler.  As a result, the unmasking was pushed
+         * into all the nmi handlers.
+         *
+         * This generic handler doesn't seem to have any issues where the
+         * unmasking occurs so it was left at the top.
+         */
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+
         for (idx = 0; idx < x86_pmu.num_counters; idx++) {
                 if (!test_bit(idx, cpuc->active_mask)) {
                         /*
@@ -1374,8 +1384,6 @@ perf_event_nmi_handler(struct notifier_block *self,
                 return NOTIFY_DONE;
         }
 
-        apic_write(APIC_LVTPC, APIC_DM_NMI);
-
         handled = x86_pmu.handle_irq(args->regs);
         if (!handled)
                 return NOTIFY_DONE;
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 43fa20b13817..e61539b07d2c 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -25,7 +25,7 @@ struct intel_percore {
 /*
  * Intel PerfMon, used on Core and later.
  */
-static const u64 intel_perfmon_event_map[] =
+static u64 intel_perfmon_event_map[PERF_COUNT_HW_MAX] __read_mostly =
 {
   [PERF_COUNT_HW_CPU_CYCLES]            = 0x003c,
   [PERF_COUNT_HW_INSTRUCTIONS]          = 0x00c0,
@@ -933,6 +933,16 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 
         cpuc = &__get_cpu_var(cpu_hw_events);
 
+        /*
+         * Some chipsets need to unmask the LVTPC in a particular spot
+         * inside the nmi handler.  As a result, the unmasking was pushed
+         * into all the nmi handlers.
+         *
+         * This handler doesn't seem to have any issues with the unmasking
+         * so it was left at the top.
+         */
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
+
         intel_pmu_disable_all();
         handled = intel_pmu_drain_bts_buffer();
         status = intel_pmu_get_status();
@@ -998,6 +1008,9 @@ intel_bts_constraints(struct perf_event *event)
         struct hw_perf_event *hwc = &event->hw;
         unsigned int hw_event, bts_event;
 
+        if (event->attr.freq)
+                return NULL;
+
         hw_event = hwc->config & INTEL_ARCH_EVENT_MASK;
         bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
 
@@ -1305,7 +1318,7 @@ static void intel_clovertown_quirks(void)
          * AJ106 could possibly be worked around by not allowing LBR
          *       usage from PEBS, including the fixup.
          * AJ68  could possibly be worked around by always programming
-         *       a pebs_event_reset[0] value and coping with the lost events.
+         *       a pebs_event_reset[0] value and coping with the lost events.
          *
          * But taken together it might just make sense to not enable PEBS on
          * these chips.
@@ -1409,6 +1422,18 @@ static __init int intel_pmu_init(void)
                 x86_pmu.percore_constraints = intel_nehalem_percore_constraints;
                 x86_pmu.enable_all = intel_pmu_nhm_enable_all;
                 x86_pmu.extra_regs = intel_nehalem_extra_regs;
+
+                if (ebx & 0x40) {
+                        /*
+                         * Erratum AAJ80 detected, we work it around by using
+                         * the BR_MISP_EXEC.ANY event. This will over-count
+                         * branch-misses, but it's still much better than the
+                         * architectural event which is often completely bogus:
+                         */
+                        intel_perfmon_event_map[PERF_COUNT_HW_BRANCH_MISSES] = 0x7f89;
+
+                        pr_cont("erratum AAJ80 worked around, ");
+                }
                 pr_cont("Nehalem events, ");
                 break;
 
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index d1f77e2934a1..e93fcd55fae1 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -950,11 +950,20 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
                         x86_pmu_stop(event, 0);
         }
 
-        if (handled) {
-                /* p4 quirk: unmask it again */
-                apic_write(APIC_LVTPC, apic_read(APIC_LVTPC) & ~APIC_LVT_MASKED);
+        if (handled)
                 inc_irq_stat(apic_perf_irqs);
-        }
+
+        /*
+         * When dealing with the unmasking of the LVTPC on P4 perf hw, it has
+         * been observed that the OVF bit flag has to be cleared first _before_
+         * the LVTPC can be unmasked.
+         *
+         * The reason is the NMI line will continue to be asserted while the OVF
+         * bit is set.  This causes a second NMI to generate if the LVTPC is
+         * unmasked before the OVF bit is cleared, leading to unknown NMI
+         * messages.
+         */
+        apic_write(APIC_LVTPC, APIC_DM_NMI);
 
         return handled;
 }