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From 0ab25d82c2929c87fc132e92192c88eeffd6f438 Mon Sep 17 00:00:00 2001
From: Sandipan Das <sandipan.das@amd.com>
Date: Thu, 21 Apr 2022 11:16:55 +0530
Subject: [PATCH 71/86] perf/x86/amd/core: Detect PerfMonV2 support
commit 21d59e3e2c403c83ba196a5857d517054124168e upstream
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@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/dc8672ecbddff394e088ca8abf94b089b8ecc2e7.1650515382.git.sandipan.das@amd.com
Signed-off-by: Zhaolong Zhang <zhaolong.zhang@windriver.com>
---
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 8e1e818f8195..b70dfa028ba5 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.
--
2.37.3
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