diff options
Diffstat (limited to 'arch/powerpc/perf/core-book3s.c')
| -rw-r--r-- | arch/powerpc/perf/core-book3s.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 67cf22083f4c..38265dc85318 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -483,7 +483,7 @@ static bool is_ebb_event(struct perf_event *event) * check that the PMU supports EBB, meaning those that don't can still * use bit 63 of the event code for something else if they wish. */ - return (ppmu->flags & PPMU_EBB) && + return (ppmu->flags & PPMU_ARCH_207S) && ((event->attr.config >> PERF_EVENT_CONFIG_EBB_SHIFT) & 1); } @@ -851,7 +851,22 @@ static void power_pmu_read(struct perf_event *event) } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev); local64_add(delta, &event->count); - local64_sub(delta, &event->hw.period_left); + + /* + * A number of places program the PMC with (0x80000000 - period_left). + * We never want period_left to be less than 1 because we will program + * the PMC with a value >= 0x800000000 and an edge detected PMC will + * roll around to 0 before taking an exception. We have seen this + * on POWER8. + * + * To fix this, clamp the minimum value of period_left to 1. + */ + do { + prev = local64_read(&event->hw.period_left); + val = prev - delta; + if (val < 1) + val = 1; + } while (local64_cmpxchg(&event->hw.period_left, prev, val) != prev); } /* @@ -1152,6 +1167,9 @@ static void power_pmu_enable(struct pmu *pmu) write_mmcr0(cpuhw, mmcr0); + if (ppmu->flags & PPMU_ARCH_207S) + mtspr(SPRN_MMCR2, 0); + /* * Enable instruction sampling if necessary */ @@ -1548,7 +1566,7 @@ static int power_pmu_event_init(struct perf_event *event) if (has_branch_stack(event)) { /* PMU has BHRB enabled */ - if (!(ppmu->flags & PPMU_BHRB)) + if (!(ppmu->flags & PPMU_ARCH_207S)) return -EOPNOTSUPP; } |