diff options
Diffstat (limited to 'arch/x86/events/amd/iommu.c')
| -rw-r--r-- | arch/x86/events/amd/iommu.c | 16 |
1 files changed, 6 insertions, 10 deletions
diff --git a/arch/x86/events/amd/iommu.c b/arch/x86/events/amd/iommu.c index e112f498a019..d4375dadd4e9 100644 --- a/arch/x86/events/amd/iommu.c +++ b/arch/x86/events/amd/iommu.c @@ -320,9 +320,7 @@ static void perf_iommu_start(struct perf_event *event, int flags) static void perf_iommu_read(struct perf_event *event) { - u64 count = 0ULL; - u64 prev_raw_count = 0ULL; - u64 delta = 0ULL; + u64 count, prev, delta; struct hw_perf_event *hwc = &event->hw; amd_iommu_pc_get_set_reg_val(_GET_DEVID(event), @@ -330,18 +328,16 @@ static void perf_iommu_read(struct perf_event *event) IOMMU_PC_COUNTER_REG, &count, false); /* IOMMU pc counter register is only 48 bits */ - count &= 0xFFFFFFFFFFFFULL; + count &= GENMASK_ULL(47, 0); - prev_raw_count = local64_read(&hwc->prev_count); - if (local64_cmpxchg(&hwc->prev_count, prev_raw_count, - count) != prev_raw_count) + prev = local64_read(&hwc->prev_count); + if (local64_cmpxchg(&hwc->prev_count, prev, count) != prev) return; - /* Handling 48-bit counter overflowing */ - delta = (count << COUNTER_SHIFT) - (prev_raw_count << COUNTER_SHIFT); + /* Handle 48-bit counter overflow */ + delta = (count << COUNTER_SHIFT) - (prev << COUNTER_SHIFT); delta >>= COUNTER_SHIFT; local64_add(delta, &event->count); - } static void perf_iommu_stop(struct perf_event *event, int flags) |