x86/perf/intel/cstate: Sanitize probing

The whole probing functionality can simply be expressed with model matching
and a bunch of structures describing the variants. This is a first step to
make that driver modular.

While at it, get rid of completely pointless comments and name the enums so
they are self explaining.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Reworked probing to clear msr[].attr for all !present msrs. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20160320185623.500381872@linutronix.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/intel/cstate.c

@@ -106,22 +106,27 @@ static ssize_t cstate_get_attr_cpumask(struct device *dev,
 				       struct device_attribute *attr,
 				       char *buf);
 
+/* Model -> events mapping */
+struct cstate_model {
+	unsigned long		core_events;
+	unsigned long		pkg_events;
+	unsigned long		quirks;
+};
+
+/* Quirk flags */
+#define SLM_PKG_C6_USE_C7_MSR	(1UL << 0)
+
 struct perf_cstate_msr {
 	u64	msr;
 	struct	perf_pmu_events_attr *attr;
-	bool	(*test)(int idx);
 };
 
 
 /* cstate_core PMU */
-
 static struct pmu cstate_core_pmu;
 static bool has_cstate_core;
 
-enum perf_cstate_core_id {
-	/*
-	 * cstate_core events
-	 */
+enum perf_cstate_core_events {
 	PERF_CSTATE_CORE_C1_RES = 0,
 	PERF_CSTATE_CORE_C3_RES,
 	PERF_CSTATE_CORE_C6_RES,
@@ -130,69 +135,16 @@ enum perf_cstate_core_id {
 	PERF_CSTATE_CORE_EVENT_MAX,
 };
 
-bool test_core(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 30: /* 45nm Nehalem    */
-	case 26: /* 45nm Nehalem-EP */
-	case 46: /* 45nm Nehalem-EX */
-
-	case 37: /* 32nm Westmere    */
-	case 44: /* 32nm Westmere-EP */
-	case 47: /* 32nm Westmere-EX */
-		if (idx == PERF_CSTATE_CORE_C3_RES ||
-		    idx == PERF_CSTATE_CORE_C6_RES)
-			return true;
-		break;
-	case 42: /* 32nm SandyBridge         */
-	case 45: /* 32nm SandyBridge-E/EN/EP */
-
-	case 58: /* 22nm IvyBridge       */
-	case 62: /* 22nm IvyBridge-EP/EX */
-
-	case 60: /* 22nm Haswell Core */
-	case 63: /* 22nm Haswell Server */
-	case 69: /* 22nm Haswell ULT */
-	case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */
-
-	case 61: /* 14nm Broadwell Core-M */
-	case 86: /* 14nm Broadwell Xeon D */
-	case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */
-	case 79: /* 14nm Broadwell Server */
-
-	case 78: /* 14nm Skylake Mobile */
-	case 94: /* 14nm Skylake Desktop */
-		if (idx == PERF_CSTATE_CORE_C3_RES ||
-		    idx == PERF_CSTATE_CORE_C6_RES ||
-		    idx == PERF_CSTATE_CORE_C7_RES)
-			return true;
-		break;
-	case 55: /* 22nm Atom "Silvermont"                */
-	case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
-	case 76: /* 14nm Atom "Airmont"                   */
-		if (idx == PERF_CSTATE_CORE_C1_RES ||
-		    idx == PERF_CSTATE_CORE_C6_RES)
-			return true;
-		break;
-	}
-
-	return false;
-}
-
 PMU_EVENT_ATTR_STRING(c1-residency, evattr_cstate_core_c1, "event=0x00");
 PMU_EVENT_ATTR_STRING(c3-residency, evattr_cstate_core_c3, "event=0x01");
 PMU_EVENT_ATTR_STRING(c6-residency, evattr_cstate_core_c6, "event=0x02");
 PMU_EVENT_ATTR_STRING(c7-residency, evattr_cstate_core_c7, "event=0x03");
 
 static struct perf_cstate_msr core_msr[] = {
-	[PERF_CSTATE_CORE_C1_RES] = { MSR_CORE_C1_RES,		&evattr_cstate_core_c1,	test_core, },
-	[PERF_CSTATE_CORE_C3_RES] = { MSR_CORE_C3_RESIDENCY,	&evattr_cstate_core_c3, test_core, },
-	[PERF_CSTATE_CORE_C6_RES] = { MSR_CORE_C6_RESIDENCY,	&evattr_cstate_core_c6, test_core, },
-	[PERF_CSTATE_CORE_C7_RES] = { MSR_CORE_C7_RESIDENCY,	&evattr_cstate_core_c7,	test_core, },
+	[PERF_CSTATE_CORE_C1_RES] = { MSR_CORE_C1_RES,		&evattr_cstate_core_c1 },
+	[PERF_CSTATE_CORE_C3_RES] = { MSR_CORE_C3_RESIDENCY,	&evattr_cstate_core_c3 },
+	[PERF_CSTATE_CORE_C6_RES] = { MSR_CORE_C6_RESIDENCY,	&evattr_cstate_core_c6 },
+	[PERF_CSTATE_CORE_C7_RES] = { MSR_CORE_C7_RESIDENCY,	&evattr_cstate_core_c7 },
 };
 
 static struct attribute *core_events_attrs[PERF_CSTATE_CORE_EVENT_MAX + 1] = {
@@ -234,18 +186,11 @@ static const struct attribute_group *core_attr_groups[] = {
 	NULL,
 };
 
-/* cstate_core PMU end */
-
-
 /* cstate_pkg PMU */
-
 static struct pmu cstate_pkg_pmu;
 static bool has_cstate_pkg;
 
-enum perf_cstate_pkg_id {
-	/*
-	 * cstate_pkg events
-	 */
+enum perf_cstate_pkg_events {
 	PERF_CSTATE_PKG_C2_RES = 0,
 	PERF_CSTATE_PKG_C3_RES,
 	PERF_CSTATE_PKG_C6_RES,
@@ -257,69 +202,6 @@ enum perf_cstate_pkg_id {
 	PERF_CSTATE_PKG_EVENT_MAX,
 };
 
-bool test_pkg(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 30: /* 45nm Nehalem    */
-	case 26: /* 45nm Nehalem-EP */
-	case 46: /* 45nm Nehalem-EX */
-
-	case 37: /* 32nm Westmere    */
-	case 44: /* 32nm Westmere-EP */
-	case 47: /* 32nm Westmere-EX */
-		if (idx == PERF_CSTATE_CORE_C3_RES ||
-		    idx == PERF_CSTATE_CORE_C6_RES ||
-		    idx == PERF_CSTATE_CORE_C7_RES)
-			return true;
-		break;
-	case 42: /* 32nm SandyBridge         */
-	case 45: /* 32nm SandyBridge-E/EN/EP */
-
-	case 58: /* 22nm IvyBridge       */
-	case 62: /* 22nm IvyBridge-EP/EX */
-
-	case 60: /* 22nm Haswell Core */
-	case 63: /* 22nm Haswell Server */
-	case 70: /* 22nm Haswell + GT3e (Intel Iris Pro graphics) */
-
-	case 61: /* 14nm Broadwell Core-M */
-	case 86: /* 14nm Broadwell Xeon D */
-	case 71: /* 14nm Broadwell + GT3e (Intel Iris Pro graphics) */
-	case 79: /* 14nm Broadwell Server */
-
-	case 78: /* 14nm Skylake Mobile */
-	case 94: /* 14nm Skylake Desktop */
-		if (idx == PERF_CSTATE_PKG_C2_RES ||
-		    idx == PERF_CSTATE_PKG_C3_RES ||
-		    idx == PERF_CSTATE_PKG_C6_RES ||
-		    idx == PERF_CSTATE_PKG_C7_RES)
-			return true;
-		break;
-	case 55: /* 22nm Atom "Silvermont"                */
-	case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
-	case 76: /* 14nm Atom "Airmont"                   */
-		if (idx == PERF_CSTATE_CORE_C6_RES)
-			return true;
-		break;
-	case 69: /* 22nm Haswell ULT */
-		if (idx == PERF_CSTATE_PKG_C2_RES ||
-		    idx == PERF_CSTATE_PKG_C3_RES ||
-		    idx == PERF_CSTATE_PKG_C6_RES ||
-		    idx == PERF_CSTATE_PKG_C7_RES ||
-		    idx == PERF_CSTATE_PKG_C8_RES ||
-		    idx == PERF_CSTATE_PKG_C9_RES ||
-		    idx == PERF_CSTATE_PKG_C10_RES)
-			return true;
-		break;
-	}
-
-	return false;
-}
-
 PMU_EVENT_ATTR_STRING(c2-residency, evattr_cstate_pkg_c2, "event=0x00");
 PMU_EVENT_ATTR_STRING(c3-residency, evattr_cstate_pkg_c3, "event=0x01");
 PMU_EVENT_ATTR_STRING(c6-residency, evattr_cstate_pkg_c6, "event=0x02");
@@ -329,13 +211,13 @@ PMU_EVENT_ATTR_STRING(c9-residency, evattr_cstate_pkg_c9, "event=0x05");
 PMU_EVENT_ATTR_STRING(c10-residency, evattr_cstate_pkg_c10, "event=0x06");
 
 static struct perf_cstate_msr pkg_msr[] = {
-	[PERF_CSTATE_PKG_C2_RES] = { MSR_PKG_C2_RESIDENCY,	&evattr_cstate_pkg_c2,	test_pkg, },
-	[PERF_CSTATE_PKG_C3_RES] = { MSR_PKG_C3_RESIDENCY,	&evattr_cstate_pkg_c3,	test_pkg, },
-	[PERF_CSTATE_PKG_C6_RES] = { MSR_PKG_C6_RESIDENCY,	&evattr_cstate_pkg_c6,	test_pkg, },
-	[PERF_CSTATE_PKG_C7_RES] = { MSR_PKG_C7_RESIDENCY,	&evattr_cstate_pkg_c7,	test_pkg, },
-	[PERF_CSTATE_PKG_C8_RES] = { MSR_PKG_C8_RESIDENCY,	&evattr_cstate_pkg_c8,	test_pkg, },
-	[PERF_CSTATE_PKG_C9_RES] = { MSR_PKG_C9_RESIDENCY,	&evattr_cstate_pkg_c9,	test_pkg, },
-	[PERF_CSTATE_PKG_C10_RES] = { MSR_PKG_C10_RESIDENCY,	&evattr_cstate_pkg_c10,	test_pkg, },
+	[PERF_CSTATE_PKG_C2_RES] = { MSR_PKG_C2_RESIDENCY,	&evattr_cstate_pkg_c2 },
+	[PERF_CSTATE_PKG_C3_RES] = { MSR_PKG_C3_RESIDENCY,	&evattr_cstate_pkg_c3 },
+	[PERF_CSTATE_PKG_C6_RES] = { MSR_PKG_C6_RESIDENCY,	&evattr_cstate_pkg_c6 },
+	[PERF_CSTATE_PKG_C7_RES] = { MSR_PKG_C7_RESIDENCY,	&evattr_cstate_pkg_c7 },
+	[PERF_CSTATE_PKG_C8_RES] = { MSR_PKG_C8_RESIDENCY,	&evattr_cstate_pkg_c8 },
+	[PERF_CSTATE_PKG_C9_RES] = { MSR_PKG_C9_RESIDENCY,	&evattr_cstate_pkg_c9 },
+	[PERF_CSTATE_PKG_C10_RES] = { MSR_PKG_C10_RESIDENCY,	&evattr_cstate_pkg_c10 },
 };
 
 static struct attribute *pkg_events_attrs[PERF_CSTATE_PKG_EVENT_MAX + 1] = {
@@ -366,8 +248,6 @@ static const struct attribute_group *pkg_attr_groups[] = {
 	NULL,
 };
 
-/* cstate_pkg PMU end*/
-
 static ssize_t cstate_get_attr_cpumask(struct device *dev,
 				       struct device_attribute *attr,
 				       char *buf)
@@ -552,48 +432,151 @@ static int cstate_cpu_notifier(struct notifier_block *self,
 	return NOTIFY_OK;
 }
 
+static struct pmu cstate_core_pmu = {
+	.attr_groups	= core_attr_groups,
+	.name		= "cstate_core",
+	.task_ctx_nr	= perf_invalid_context,
+	.event_init	= cstate_pmu_event_init,
+	.add		= cstate_pmu_event_add,
+	.del		= cstate_pmu_event_del,
+	.start		= cstate_pmu_event_start,
+	.stop		= cstate_pmu_event_stop,
+	.read		= cstate_pmu_event_update,
+	.capabilities	= PERF_PMU_CAP_NO_INTERRUPT,
+};
+
+static struct pmu cstate_pkg_pmu = {
+	.attr_groups	= pkg_attr_groups,
+	.name		= "cstate_pkg",
+	.task_ctx_nr	= perf_invalid_context,
+	.event_init	= cstate_pmu_event_init,
+	.add		= cstate_pmu_event_add,
+	.del		= cstate_pmu_event_del,
+	.start		= cstate_pmu_event_start,
+	.stop		= cstate_pmu_event_stop,
+	.read		= cstate_pmu_event_update,
+	.capabilities	= PERF_PMU_CAP_NO_INTERRUPT,
+};
+
+static const struct cstate_model nhm_cstates __initconst = {
+	.core_events		= BIT(PERF_CSTATE_CORE_C3_RES) |
+				  BIT(PERF_CSTATE_CORE_C6_RES),
+
+	.pkg_events		= BIT(PERF_CSTATE_PKG_C3_RES) |
+				  BIT(PERF_CSTATE_PKG_C6_RES) |
+				  BIT(PERF_CSTATE_PKG_C7_RES),
+};
+
+static const struct cstate_model snb_cstates __initconst = {
+	.core_events		= BIT(PERF_CSTATE_CORE_C3_RES) |
+				  BIT(PERF_CSTATE_CORE_C6_RES) |
+				  BIT(PERF_CSTATE_CORE_C7_RES),
+
+	.pkg_events		= BIT(PERF_CSTATE_PKG_C2_RES) |
+				  BIT(PERF_CSTATE_PKG_C3_RES) |
+				  BIT(PERF_CSTATE_PKG_C6_RES) |
+				  BIT(PERF_CSTATE_PKG_C7_RES),
+};
+
+static const struct cstate_model hswult_cstates __initconst = {
+	.core_events		= BIT(PERF_CSTATE_CORE_C3_RES) |
+				  BIT(PERF_CSTATE_CORE_C6_RES) |
+				  BIT(PERF_CSTATE_CORE_C7_RES),
+
+	.pkg_events		= BIT(PERF_CSTATE_PKG_C2_RES) |
+				  BIT(PERF_CSTATE_PKG_C3_RES) |
+				  BIT(PERF_CSTATE_PKG_C6_RES) |
+				  BIT(PERF_CSTATE_PKG_C7_RES) |
+				  BIT(PERF_CSTATE_PKG_C8_RES) |
+				  BIT(PERF_CSTATE_PKG_C9_RES) |
+				  BIT(PERF_CSTATE_PKG_C10_RES),
+};
+
+static const struct cstate_model slm_cstates __initconst = {
+	.core_events		= BIT(PERF_CSTATE_CORE_C1_RES) |
+				  BIT(PERF_CSTATE_CORE_C6_RES),
+
+	.pkg_events		= BIT(PERF_CSTATE_PKG_C6_RES),
+	.quirks			= SLM_PKG_C6_USE_C7_MSR,
+};
+
+#define X86_CSTATES_MODEL(model, states)				\
+	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long) &(states) }
+
+static const struct x86_cpu_id intel_cstates_match[] __initconst = {
+	X86_CSTATES_MODEL(30, nhm_cstates),    /* 45nm Nehalem              */
+	X86_CSTATES_MODEL(26, nhm_cstates),    /* 45nm Nehalem-EP           */
+	X86_CSTATES_MODEL(46, nhm_cstates),    /* 45nm Nehalem-EX           */
+
+	X86_CSTATES_MODEL(37, nhm_cstates),    /* 32nm Westmere             */
+	X86_CSTATES_MODEL(44, nhm_cstates),    /* 32nm Westmere-EP          */
+	X86_CSTATES_MODEL(47, nhm_cstates),    /* 32nm Westmere-EX          */
+
+	X86_CSTATES_MODEL(42, snb_cstates),    /* 32nm SandyBridge          */
+	X86_CSTATES_MODEL(45, snb_cstates),    /* 32nm SandyBridge-E/EN/EP  */
+
+	X86_CSTATES_MODEL(58, snb_cstates),    /* 22nm IvyBridge            */
+	X86_CSTATES_MODEL(62, snb_cstates),    /* 22nm IvyBridge-EP/EX      */
+
+	X86_CSTATES_MODEL(60, snb_cstates),    /* 22nm Haswell Core         */
+	X86_CSTATES_MODEL(63, snb_cstates),    /* 22nm Haswell Server       */
+	X86_CSTATES_MODEL(70, snb_cstates),    /* 22nm Haswell + GT3e       */
+
+	X86_CSTATES_MODEL(69, hswult_cstates), /* 22nm Haswell ULT          */
+
+	X86_CSTATES_MODEL(55, slm_cstates),    /* 22nm Atom Silvermont      */
+	X86_CSTATES_MODEL(77, slm_cstates),    /* 22nm Atom Avoton/Rangely  */
+	X86_CSTATES_MODEL(76, slm_cstates),    /* 22nm Atom Airmont         */
+
+	X86_CSTATES_MODEL(61, snb_cstates),    /* 14nm Broadwell Core-M     */
+	X86_CSTATES_MODEL(86, snb_cstates),    /* 14nm Broadwell Xeon D     */
+	X86_CSTATES_MODEL(71, snb_cstates),    /* 14nm Broadwell + GT3e     */
+	X86_CSTATES_MODEL(79, snb_cstates),    /* 14nm Broadwell Server     */
+
+	X86_CSTATES_MODEL(78, snb_cstates),    /* 14nm Skylake Mobile       */
+	X86_CSTATES_MODEL(94, snb_cstates),    /* 14nm Skylake Desktop      */
+	{ },
+};
+MODULE_DEVICE_TABLE(x86cpu, intel_cstates_match);
+
 /*
  * Probe the cstate events and insert the available one into sysfs attrs
- * Return false if there is no available events.
+ * Return false if there are no available events.
  */
-static bool cstate_probe_msr(struct perf_cstate_msr *msr,
-			     struct attribute	**events_attrs,
-			     int max_event_nr)
+static bool __init cstate_probe_msr(const unsigned long evmsk, int max,
+                                   struct perf_cstate_msr *msr,
+                                   struct attribute **attrs)
 {
-	int i, j = 0;
+	bool found = false;
+	unsigned int bit;
 	u64 val;
 
-	/* Probe the cstate events. */
-	for (i = 0; i < max_event_nr; i++) {
-		if (!msr[i].test(i) || rdmsrl_safe(msr[i].msr, &val))
-			msr[i].attr = NULL;
-	}
-
-	/* List remaining events in the sysfs attrs. */
-	for (i = 0; i < max_event_nr; i++) {
-		if (msr[i].attr)
-			events_attrs[j++] = &msr[i].attr->attr.attr;
+	for (bit = 0; bit < max; bit++) {
+		if (test_bit(bit, &evmsk) && !rdmsrl_safe(msr[bit].msr, &val)) {
+			*attrs++ = &msr[bit].attr->attr.attr;
+			found = true;
+		} else {
+			msr[bit].attr = NULL;
+		}
 	}
-	events_attrs[j] = NULL;
+	*attrs = NULL;
 
-	return (j > 0) ? true : false;
+	return found;
 }
 
-static int __init cstate_init(void)
+static int __init cstate_probe(const struct cstate_model *cm)
 {
 	/* SLM has different MSR for PKG C6 */
-	switch (boot_cpu_data.x86_model) {
-	case 55:
-	case 76:
-	case 77:
+	if (cm->quirks & SLM_PKG_C6_USE_C7_MSR)
 		pkg_msr[PERF_CSTATE_PKG_C6_RES].msr = MSR_PKG_C7_RESIDENCY;
-	}
 
-	if (cstate_probe_msr(core_msr, core_events_attrs, PERF_CSTATE_CORE_EVENT_MAX))
-		has_cstate_core = true;
+	has_cstate_core = cstate_probe_msr(cm->core_events,
+					   PERF_CSTATE_CORE_EVENT_MAX,
+					   core_msr, core_events_attrs);
 
-	if (cstate_probe_msr(pkg_msr, pkg_events_attrs, PERF_CSTATE_PKG_EVENT_MAX))
-		has_cstate_pkg = true;
+	has_cstate_pkg = cstate_probe_msr(cm->pkg_events,
+					  PERF_CSTATE_PKG_EVENT_MAX,
+					  pkg_msr, pkg_events_attrs);
 
 	return (has_cstate_core || has_cstate_pkg) ? 0 : -ENODEV;
 }
@@ -612,32 +595,6 @@ static void __init cstate_cpumask_init(void)
 	cpu_notifier_register_done();
 }
 
-static struct pmu cstate_core_pmu = {
-	.attr_groups	= core_attr_groups,
-	.name		= "cstate_core",
-	.task_ctx_nr	= perf_invalid_context,
-	.event_init	= cstate_pmu_event_init,
-	.add		= cstate_pmu_event_add, /* must have */
-	.del		= cstate_pmu_event_del, /* must have */
-	.start		= cstate_pmu_event_start,
-	.stop		= cstate_pmu_event_stop,
-	.read		= cstate_pmu_event_update,
-	.capabilities	= PERF_PMU_CAP_NO_INTERRUPT,
-};
-
-static struct pmu cstate_pkg_pmu = {
-	.attr_groups	= pkg_attr_groups,
-	.name		= "cstate_pkg",
-	.task_ctx_nr	= perf_invalid_context,
-	.event_init	= cstate_pmu_event_init,
-	.add		= cstate_pmu_event_add, /* must have */
-	.del		= cstate_pmu_event_del, /* must have */
-	.start		= cstate_pmu_event_start,
-	.stop		= cstate_pmu_event_stop,
-	.read		= cstate_pmu_event_update,
-	.capabilities	= PERF_PMU_CAP_NO_INTERRUPT,
-};
-
 static void __init cstate_pmus_register(void)
 {
 	int err;
@@ -659,12 +616,17 @@ static void __init cstate_pmus_register(void)
 
 static int __init cstate_pmu_init(void)
 {
+	const struct x86_cpu_id *id;
 	int err;
 
-	if (cpu_has_hypervisor)
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return -ENODEV;
 
-	err = cstate_init();
+	id = x86_match_cpu(intel_cstates_match);
+	if (!id)
+		return -ENODEV;
+
+	err = cstate_probe((const struct cstate_model *) id->driver_data);
 	if (err)
 		return err;
 
@@ -674,5 +636,4 @@ static int __init cstate_pmu_init(void)
 
 	return 0;
 }
-
 device_initcall(cstate_pmu_init);