linux-kernel - [PATCH 5/9] perf/x86/intel: Support Architectural PerfMon Extension leaf

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Date:   Thu,  1 Dec 2022 11:57:00 -0800
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     ak@...ux.intel.com, eranian@...gle.com, irogers@...gle.com,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH 5/9] perf/x86/intel: Support Architectural PerfMon Extension leaf

From: Kan Liang <kan.liang@...ux.intel.com>

The new CPUID leaf 0x23 reports the "true view" of PMU resources.

The sub-leaf 1 reports the available general-purpose counters and fixed
counters. Update the number of counters and fixed counters when the
sub-leaf is detected.

Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 arch/x86/events/intel/core.c      | 22 ++++++++++++++++++++++
 arch/x86/include/asm/perf_event.h |  8 ++++++++
 2 files changed, 30 insertions(+)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index b97eb3bff6ae..9d49c6db40d3 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -4588,6 +4588,25 @@ static void flip_smm_bit(void *data)
 	}
 }
 
+static void intel_pmu_check_num_counters(int *num_counters,
+					 int *num_counters_fixed,
+					 u64 *intel_ctrl, u64 fixed_mask);
+
+static void update_pmu_cap(struct x86_hybrid_pmu *pmu)
+{
+	unsigned int sub_bitmaps = cpuid_eax(ARCH_PERFMON_EXT_LEAF);
+	unsigned int eax, ebx, ecx, edx;
+
+	if (sub_bitmaps & ARCH_PERFMON_NUM_COUNTER_LEAF_BIT) {
+		cpuid_count(ARCH_PERFMON_EXT_LEAF, ARCH_PERFMON_NUM_COUNTER_LEAF,
+			    &eax, &ebx, &ecx, &edx);
+		pmu->num_counters = fls(eax);
+		pmu->num_counters_fixed = fls(ebx);
+		intel_pmu_check_num_counters(&pmu->num_counters, &pmu->num_counters_fixed,
+					     &pmu->intel_ctrl, ebx);
+	}
+}
+
 static bool init_hybrid_pmu(int cpu)
 {
 	struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
@@ -4613,6 +4632,9 @@ static bool init_hybrid_pmu(int cpu)
 	if (!cpumask_empty(&pmu->supported_cpus))
 		goto end;
 
+	if (this_cpu_has(X86_FEATURE_ARCH_PERFMON_EXT))
+		update_pmu_cap(pmu);
+
 	if (!check_hw_exists(&pmu->pmu, pmu->num_counters, pmu->num_counters_fixed))
 		return false;
 
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 9ac46dbe57d4..98efe1d4005b 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -159,6 +159,14 @@ union cpuid10_edx {
 	unsigned int full;
 };
 
+/*
+ * Intel "Architectural Performance Monitoring extension" CPUID
+ * detection/enumeration details:
+ */
+#define ARCH_PERFMON_EXT_LEAF			0x00000023
+#define ARCH_PERFMON_NUM_COUNTER_LEAF_BIT	0x1
+#define ARCH_PERFMON_NUM_COUNTER_LEAF		0x1
+
 /*
  * Intel Architectural LBR CPUID detection/enumeration details:
  */
-- 
2.35.1