1 files changed, 292 insertions, 0 deletions
diff --git a/arch/x86/events/msr.c b/arch/x86/events/msr.c
new file mode 100644
index 000000000..ace6c1e75
--- /dev/null
+++ b/arch/x86/events/msr.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/perf_event.h>
+#include <linux/nospec.h>
+#include <asm/intel-family.h>
+
+enum perf_msr_id {
+	PERF_MSR_TSC			= 0,
+	PERF_MSR_APERF			= 1,
+	PERF_MSR_MPERF			= 2,
+	PERF_MSR_PPERF			= 3,
+	PERF_MSR_SMI			= 4,
+	PERF_MSR_PTSC			= 5,
+	PERF_MSR_IRPERF			= 6,
+	PERF_MSR_THERM			= 7,
+	PERF_MSR_THERM_SNAP		= 8,
+	PERF_MSR_THERM_UNIT		= 9,
+	PERF_MSR_EVENT_MAX,
+};
+
+static bool test_aperfmperf(int idx)
+{
+	return boot_cpu_has(X86_FEATURE_APERFMPERF);
+}
+
+static bool test_ptsc(int idx)
+{
+	return boot_cpu_has(X86_FEATURE_PTSC);
+}
+
+static bool test_irperf(int idx)
+{
+	return boot_cpu_has(X86_FEATURE_IRPERF);
+}
+
+static bool test_therm_status(int idx)
+{
+	return boot_cpu_has(X86_FEATURE_DTHERM);
+}
+
+static bool test_intel(int idx)
+{
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||
+	    boot_cpu_data.x86 != 6)
+		return false;
+
+	switch (boot_cpu_data.x86_model) {
+	case INTEL_FAM6_NEHALEM:
+	case INTEL_FAM6_NEHALEM_G:
+	case INTEL_FAM6_NEHALEM_EP:
+	case INTEL_FAM6_NEHALEM_EX:
+
+	case INTEL_FAM6_WESTMERE:
+	case INTEL_FAM6_WESTMERE_EP:
+	case INTEL_FAM6_WESTMERE_EX:
+
+	case INTEL_FAM6_SANDYBRIDGE:
+	case INTEL_FAM6_SANDYBRIDGE_X:
+
+	case INTEL_FAM6_IVYBRIDGE:
+	case INTEL_FAM6_IVYBRIDGE_X:
+
+	case INTEL_FAM6_HASWELL_CORE:
+	case INTEL_FAM6_HASWELL_X:
+	case INTEL_FAM6_HASWELL_ULT:
+	case INTEL_FAM6_HASWELL_GT3E:
+
+	case INTEL_FAM6_BROADWELL_CORE:
+	case INTEL_FAM6_BROADWELL_XEON_D:
+	case INTEL_FAM6_BROADWELL_GT3E:
+	case INTEL_FAM6_BROADWELL_X:
+
+	case INTEL_FAM6_ATOM_SILVERMONT:
+	case INTEL_FAM6_ATOM_SILVERMONT_X:
+	case INTEL_FAM6_ATOM_AIRMONT:
+
+	case INTEL_FAM6_ATOM_GOLDMONT:
+	case INTEL_FAM6_ATOM_GOLDMONT_X:
+
+	case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
+
+	case INTEL_FAM6_XEON_PHI_KNL:
+	case INTEL_FAM6_XEON_PHI_KNM:
+		if (idx == PERF_MSR_SMI)
+			return true;
+		break;
+
+	case INTEL_FAM6_SKYLAKE_MOBILE:
+	case INTEL_FAM6_SKYLAKE_DESKTOP:
+	case INTEL_FAM6_SKYLAKE_X:
+	case INTEL_FAM6_KABYLAKE_MOBILE:
+	case INTEL_FAM6_KABYLAKE_DESKTOP:
+	case INTEL_FAM6_ICELAKE_MOBILE:
+		if (idx == PERF_MSR_SMI || idx == PERF_MSR_PPERF)
+			return true;
+		break;
+	}
+
+	return false;
+}
+
+struct perf_msr {
+	u64	msr;
+	struct	perf_pmu_events_attr *attr;
+	bool	(*test)(int idx);
+};
+
+PMU_EVENT_ATTR_STRING(tsc,				evattr_tsc,		"event=0x00"	);
+PMU_EVENT_ATTR_STRING(aperf,				evattr_aperf,		"event=0x01"	);
+PMU_EVENT_ATTR_STRING(mperf,				evattr_mperf,		"event=0x02"	);
+PMU_EVENT_ATTR_STRING(pperf,				evattr_pperf,		"event=0x03"	);
+PMU_EVENT_ATTR_STRING(smi,				evattr_smi,		"event=0x04"	);
+PMU_EVENT_ATTR_STRING(ptsc,				evattr_ptsc,		"event=0x05"	);
+PMU_EVENT_ATTR_STRING(irperf,				evattr_irperf,		"event=0x06"	);
+PMU_EVENT_ATTR_STRING(cpu_thermal_margin,		evattr_therm,		"event=0x07"	);
+PMU_EVENT_ATTR_STRING(cpu_thermal_margin.snapshot,	evattr_therm_snap,	"1"		);
+PMU_EVENT_ATTR_STRING(cpu_thermal_margin.unit,		evattr_therm_unit,	"C"		);
+
+static struct perf_msr msr[] = {
+	[PERF_MSR_TSC]		= { 0,				&evattr_tsc,		NULL,			},
+	[PERF_MSR_APERF]	= { MSR_IA32_APERF,		&evattr_aperf,		test_aperfmperf,	},
+	[PERF_MSR_MPERF]	= { MSR_IA32_MPERF,		&evattr_mperf,		test_aperfmperf,	},
+	[PERF_MSR_PPERF]	= { MSR_PPERF,			&evattr_pperf,		test_intel,		},
+	[PERF_MSR_SMI]		= { MSR_SMI_COUNT,		&evattr_smi,		test_intel,		},
+	[PERF_MSR_PTSC]		= { MSR_F15H_PTSC,		&evattr_ptsc,		test_ptsc,		},
+	[PERF_MSR_IRPERF]	= { MSR_F17H_IRPERF,		&evattr_irperf,		test_irperf,		},
+	[PERF_MSR_THERM]	= { MSR_IA32_THERM_STATUS,	&evattr_therm,		test_therm_status,	},
+	[PERF_MSR_THERM_SNAP]	= { MSR_IA32_THERM_STATUS,	&evattr_therm_snap,	test_therm_status,	},
+	[PERF_MSR_THERM_UNIT]	= { MSR_IA32_THERM_STATUS,	&evattr_therm_unit,	test_therm_status,	},
+};
+
+static struct attribute *events_attrs[PERF_MSR_EVENT_MAX + 1] = {
+	NULL,
+};
+
+static struct attribute_group events_attr_group = {
+	.name = "events",
+	.attrs = events_attrs,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-63");
+static struct attribute *format_attrs[] = {
+	&format_attr_event.attr,
+	NULL,
+};
+static struct attribute_group format_attr_group = {
+	.name = "format",
+	.attrs = format_attrs,
+};
+
+static const struct attribute_group *attr_groups[] = {
+	&events_attr_group,
+	&format_attr_group,
+	NULL,
+};
+
+static int msr_event_init(struct perf_event *event)
+{
+	u64 cfg = event->attr.config;
+
+	if (event->attr.type != event->pmu->type)
+		return -ENOENT;
+
+	/* unsupported modes and filters */
+	if (event->attr.exclude_user   ||
+	    event->attr.exclude_kernel ||
+	    event->attr.exclude_hv     ||
+	    event->attr.exclude_idle   ||
+	    event->attr.exclude_host   ||
+	    event->attr.exclude_guest  ||
+	    event->attr.sample_period) /* no sampling */
+		return -EINVAL;
+
+	if (cfg >= PERF_MSR_EVENT_MAX)
+		return -EINVAL;
+
+	cfg = array_index_nospec((unsigned long)cfg, PERF_MSR_EVENT_MAX);
+
+	if (!msr[cfg].attr)
+		return -EINVAL;
+
+	event->hw.idx		= -1;
+	event->hw.event_base	= msr[cfg].msr;
+	event->hw.config	= cfg;
+
+	return 0;
+}
+
+static inline u64 msr_read_counter(struct perf_event *event)
+{
+	u64 now;
+
+	if (event->hw.event_base)
+		rdmsrl(event->hw.event_base, now);
+	else
+		now = rdtsc_ordered();
+
+	return now;
+}
+
+static void msr_event_update(struct perf_event *event)
+{
+	u64 prev, now;
+	s64 delta;
+
+	/* Careful, an NMI might modify the previous event value: */
+again:
+	prev = local64_read(&event->hw.prev_count);
+	now = msr_read_counter(event);
+
+	if (local64_cmpxchg(&event->hw.prev_count, prev, now) != prev)
+		goto again;
+
+	delta = now - prev;
+	if (unlikely(event->hw.event_base == MSR_SMI_COUNT)) {
+		delta = sign_extend64(delta, 31);
+		local64_add(delta, &event->count);
+	} else if (unlikely(event->hw.event_base == MSR_IA32_THERM_STATUS)) {
+		/* If valid, extract digital readout, otherwise set to -1: */
+		now = now & (1ULL << 31) ? (now >> 16) & 0x3f :  -1;
+		local64_set(&event->count, now);
+	} else {
+		local64_add(delta, &event->count);
+	}
+}
+
+static void msr_event_start(struct perf_event *event, int flags)
+{
+	u64 now = msr_read_counter(event);
+
+	local64_set(&event->hw.prev_count, now);
+}
+
+static void msr_event_stop(struct perf_event *event, int flags)
+{
+	msr_event_update(event);
+}
+
+static void msr_event_del(struct perf_event *event, int flags)
+{
+	msr_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int msr_event_add(struct perf_event *event, int flags)
+{
+	if (flags & PERF_EF_START)
+		msr_event_start(event, flags);
+
+	return 0;
+}
+
+static struct pmu pmu_msr = {
+	.task_ctx_nr	= perf_sw_context,
+	.attr_groups	= attr_groups,
+	.event_init	= msr_event_init,
+	.add		= msr_event_add,
+	.del		= msr_event_del,
+	.start		= msr_event_start,
+	.stop		= msr_event_stop,
+	.read		= msr_event_update,
+	.capabilities	= PERF_PMU_CAP_NO_INTERRUPT,
+};
+
+static int __init msr_init(void)
+{
+	int i, j = 0;
+
+	if (!boot_cpu_has(X86_FEATURE_TSC)) {
+		pr_cont("no MSR PMU driver.\n");
+		return 0;
+	}
+
+	/* Probe the MSRs. */
+	for (i = PERF_MSR_TSC + 1; i < PERF_MSR_EVENT_MAX; i++) {
+		u64 val;
+
+		/* Virt sucks; you cannot tell if a R/O MSR is present :/ */
+		if (!msr[i].test(i) || rdmsrl_safe(msr[i].msr, &val))
+			msr[i].attr = NULL;
+	}
+
+	/* List remaining MSRs in the sysfs attrs. */
+	for (i = 0; i < PERF_MSR_EVENT_MAX; i++) {
+		if (msr[i].attr)
+			events_attrs[j++] = &msr[i].attr->attr.attr;
+	}
+	events_attrs[j] = NULL;
+
+	perf_pmu_register(&pmu_msr, "msr", -1);
+
+	return 0;
+}
+device_initcall(msr_init);