The following commit has been merged into the perf/core branch of tip: Commit-ID: 28c332ff4d11060ed3b4a2029016ba9a83f1bceb Gitweb: https://git.kernel.org/tip/28c332ff4d11060ed3b4a2029016ba9a83f1bceb Author: Sandipan Das <sandipan.das@xxxxxxx> AuthorDate: Thu, 21 Apr 2022 11:16:55 +05:30 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Fri, 29 Apr 2022 11:06:26 +02:00 perf/x86/amd/core: Detect PerfMonV2 support AMD Performance Monitoring Version 2 (PerfMonV2) introduces some new Core PMU features such as detection of the number of available PMCs and managing PMCs using global registers namely, PerfCntrGlobalCtl and PerfCntrGlobalStatus. Clearing PerfCntrGlobalCtl and PerfCntrGlobalStatus ensures that all PMCs are inactive and have no pending overflows when CPUs are onlined or offlined. The PMU version (x86_pmu.version) now indicates PerfMonV2 support and will be used to bypass the new features on unsupported processors. Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/dc8672ecbddff394e088ca8abf94b089b8ecc2e7.1650515382.git.sandipan.das@xxxxxxx --- arch/x86/events/amd/core.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index 8e1e818..b70dfa0 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -19,6 +19,9 @@ static unsigned long perf_nmi_window; #define AMD_MERGE_EVENT ((0xFULL << 32) | 0xFFULL) #define AMD_MERGE_EVENT_ENABLE (AMD_MERGE_EVENT | ARCH_PERFMON_EVENTSEL_ENABLE) +/* PMC Enable and Overflow bits for PerfCntrGlobal* registers */ +static u64 amd_pmu_global_cntr_mask __read_mostly; + static __initconst const u64 amd_hw_cache_event_ids [PERF_COUNT_HW_CACHE_MAX] [PERF_COUNT_HW_CACHE_OP_MAX] @@ -578,6 +581,18 @@ static struct amd_nb *amd_alloc_nb(int cpu) return nb; } +static void amd_pmu_cpu_reset(int cpu) +{ + if (x86_pmu.version < 2) + return; + + /* Clear enable bits i.e. PerfCntrGlobalCtl.PerfCntrEn */ + wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_CTL, 0); + + /* Clear overflow bits i.e. PerfCntrGLobalStatus.PerfCntrOvfl */ + wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR, amd_pmu_global_cntr_mask); +} + static int amd_pmu_cpu_prepare(int cpu) { struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu); @@ -625,6 +640,7 @@ static void amd_pmu_cpu_starting(int cpu) cpuc->amd_nb->refcnt++; amd_brs_reset(); + amd_pmu_cpu_reset(cpu); } static void amd_pmu_cpu_dead(int cpu) @@ -644,6 +660,8 @@ static void amd_pmu_cpu_dead(int cpu) cpuhw->amd_nb = NULL; } + + amd_pmu_cpu_reset(cpu); } /* @@ -1185,6 +1203,15 @@ static int __init amd_core_pmu_init(void) x86_pmu.eventsel = MSR_F15H_PERF_CTL; x86_pmu.perfctr = MSR_F15H_PERF_CTR; x86_pmu.num_counters = AMD64_NUM_COUNTERS_CORE; + + /* Check for Performance Monitoring v2 support */ + if (boot_cpu_has(X86_FEATURE_PERFMON_V2)) { + /* Update PMU version for later usage */ + x86_pmu.version = 2; + + amd_pmu_global_cntr_mask = (1ULL << x86_pmu.num_counters) - 1; + } + /* * AMD Core perfctr has separate MSRs for the NB events, see * the amd/uncore.c driver.
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