From: "Rob Herring (Arm)" robh@kernel.org
mainline inclusion from mainline-v6.9-rc1 commit 81e15ca3e523a508d62806fe681c1d289361ca16 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9Q7QP CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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If the user has requested a counting threshold for the CPU cycles event, then the fixed cycle counter can't be assigned as it lacks threshold support. Currently, the thresholds will work or not randomly depending on which counter the event is assigned.
While using thresholds for CPU cycles doesn't make much sense, it can be useful for testing purposes.
Fixes: 816c26754447 ("arm64: perf: Add support for event counting threshold") Signed-off-by: Rob Herring (Arm) robh@kernel.org Acked-by: Mark Rutland mark.rutland@arm.com Link: https://lore.kernel.org/r/20240626-arm-pmu-3-9-icntr-v2-1-c9784b4f4065@kerne... Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Junhao He hejunhao3@huawei.com --- drivers/perf/arm_pmuv3.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 3fe3ecb5a66b..21ea93740f65 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -338,6 +338,11 @@ static bool armv8pmu_event_want_user_access(struct perf_event *event) return ATTR_CFG_GET_FLD(&event->attr, rdpmc); }
+static u32 armv8pmu_event_get_threshold(struct perf_event_attr *attr) +{ + return ATTR_CFG_GET_FLD(attr, threshold); +} + static u8 armv8pmu_event_threshold_control(struct perf_event_attr *attr) { u8 th_compare = ATTR_CFG_GET_FLD(attr, threshold_compare); @@ -941,7 +946,8 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events *cpuc, unsigned long evtype = hwc->config_base & ARMV8_PMU_EVTYPE_EVENT;
/* Always prefer to place a cycle counter into the cycle counter. */ - if (evtype == ARMV8_PMUV3_PERFCTR_CPU_CYCLES) { + if ((evtype == ARMV8_PMUV3_PERFCTR_CPU_CYCLES) && + !armv8pmu_event_get_threshold(&event->attr)) { if (!test_and_set_bit(ARMV8_IDX_CYCLE_COUNTER, cpuc->used_mask)) return ARMV8_IDX_CYCLE_COUNTER; else if (armv8pmu_event_is_64bit(event) && @@ -1033,7 +1039,7 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event, * If FEAT_PMUv3_TH isn't implemented, then THWIDTH (threshold_max) will * be 0 and will also trigger this check, preventing it from being used. */ - th = ATTR_CFG_GET_FLD(attr, threshold); + th = armv8pmu_event_get_threshold(attr); if (th > threshold_max(cpu_pmu)) { pr_debug("PMU event threshold exceeds max value\n"); return -EINVAL;