perf/x86/amd: Enable northbridge performance counters on AMD family 15h

On AMD family 15h processors, there are 4 new performance
counters (in addition to 6 core performance counters) that can
be used for counting northbridge events (i.e. DRAM accesses).

Their bit fields are almost identical to the core performance
counters. However, unlike the core performance counters, these
MSRs are shared between multiple cores (that share the same
northbridge).

We will reuse the same code path as existing family 10h
northbridge event constraints handler logic to enforce
this sharing.

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Stephane Eranian <eranian@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jacob Shin <jacob.shin@amd.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1360171589-6381-7-git-send-email-jacob.shin@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/cpufeature.h

@@ -167,6 +167,7 @@
 #define X86_FEATURE_TBM		(6*32+21) /* trailing bit manipulations */
 #define X86_FEATURE_TOPOEXT	(6*32+22) /* topology extensions CPUID leafs */
 #define X86_FEATURE_PERFCTR_CORE (6*32+23) /* core performance counter extensions */
+#define X86_FEATURE_PERFCTR_NB  (6*32+24) /* NB performance counter extensions */
 
 /*
  * Auxiliary flags: Linux defined - For features scattered in various
@@ -309,6 +310,7 @@ extern const char * const x86_power_flags[32];
 #define cpu_has_hypervisor	boot_cpu_has(X86_FEATURE_HYPERVISOR)
 #define cpu_has_pclmulqdq	boot_cpu_has(X86_FEATURE_PCLMULQDQ)
 #define cpu_has_perfctr_core	boot_cpu_has(X86_FEATURE_PERFCTR_CORE)
+#define cpu_has_perfctr_nb	boot_cpu_has(X86_FEATURE_PERFCTR_NB)
 #define cpu_has_cx8		boot_cpu_has(X86_FEATURE_CX8)
 #define cpu_has_cx16		boot_cpu_has(X86_FEATURE_CX16)
 #define cpu_has_eager_fpu	boot_cpu_has(X86_FEATURE_EAGER_FPU)

arch/x86/include/asm/perf_event.h

@@ -29,9 +29,14 @@
 #define ARCH_PERFMON_EVENTSEL_INV			(1ULL << 23)
 #define ARCH_PERFMON_EVENTSEL_CMASK			0xFF000000ULL
 
+#define AMD64_EVENTSEL_INT_CORE_ENABLE			(1ULL << 36)
 #define AMD64_EVENTSEL_GUESTONLY			(1ULL << 40)
 #define AMD64_EVENTSEL_HOSTONLY				(1ULL << 41)
 
+#define AMD64_EVENTSEL_INT_CORE_SEL_SHIFT		37
+#define AMD64_EVENTSEL_INT_CORE_SEL_MASK		\
+	(0xFULL << AMD64_EVENTSEL_INT_CORE_SEL_SHIFT)
+
 #define AMD64_EVENTSEL_EVENT	\
 	(ARCH_PERFMON_EVENTSEL_EVENT | (0x0FULL << 32))
 #define INTEL_ARCH_EVENT_MASK	\
@@ -46,8 +51,12 @@
 #define AMD64_RAW_EVENT_MASK		\
 	(X86_RAW_EVENT_MASK          |  \
 	 AMD64_EVENTSEL_EVENT)
+#define AMD64_RAW_EVENT_MASK_NB		\
+	(AMD64_EVENTSEL_EVENT        |  \
+	 ARCH_PERFMON_EVENTSEL_UMASK)
 #define AMD64_NUM_COUNTERS				4
 #define AMD64_NUM_COUNTERS_CORE				6
+#define AMD64_NUM_COUNTERS_NB				4
 
 #define ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL		0x3c
 #define ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK		(0x00 << 8)

arch/x86/include/uapi/asm/msr-index.h

@@ -194,6 +194,8 @@
 /* Fam 15h MSRs */
 #define MSR_F15H_PERF_CTL		0xc0010200
 #define MSR_F15H_PERF_CTR		0xc0010201
+#define MSR_F15H_NB_PERF_CTL		0xc0010240
+#define MSR_F15H_NB_PERF_CTR		0xc0010241
 
 /* Fam 10h MSRs */
 #define MSR_FAM10H_MMIO_CONF_BASE	0xc0010058

arch/x86/kernel/cpu/perf_event_amd.c

@@ -132,11 +132,14 @@ static u64 amd_pmu_event_map(int hw_event)
 	return amd_perfmon_event_map[hw_event];
 }
 
+static struct event_constraint *amd_nb_event_constraint;
+
 /*
  * Previously calculated offsets
  */
 static unsigned int event_offsets[X86_PMC_IDX_MAX] __read_mostly;
 static unsigned int count_offsets[X86_PMC_IDX_MAX] __read_mostly;
+static unsigned int rdpmc_indexes[X86_PMC_IDX_MAX] __read_mostly;
 
 /*
  * Legacy CPUs:
@@ -144,10 +147,14 @@ static unsigned int count_offsets[X86_PMC_IDX_MAX] __read_mostly;
  *
  * CPUs with core performance counter extensions:
  *   6 counters starting at 0xc0010200 each offset by 2
+ *
+ * CPUs with north bridge performance counter extensions:
+ *   4 additional counters starting at 0xc0010240 each offset by 2
+ *   (indexed right above either one of the above core counters)
  */
 static inline int amd_pmu_addr_offset(int index, bool eventsel)
 {
-	int offset;
+	int offset, first, base;
 
 	if (!index)
 		return index;
@@ -160,7 +167,23 @@ static inline int amd_pmu_addr_offset(int index, bool eventsel)
 	if (offset)
 		return offset;
 
-	if (!cpu_has_perfctr_core)
+	if (amd_nb_event_constraint &&
+	    test_bit(index, amd_nb_event_constraint->idxmsk)) {
+		/*
+		 * calculate the offset of NB counters with respect to
+		 * base eventsel or perfctr
+		 */
+
+		first = find_first_bit(amd_nb_event_constraint->idxmsk,
+				       X86_PMC_IDX_MAX);
+
+		if (eventsel)
+			base = MSR_F15H_NB_PERF_CTL - x86_pmu.eventsel;
+		else
+			base = MSR_F15H_NB_PERF_CTR - x86_pmu.perfctr;
+
+		offset = base + ((index - first) << 1);
+	} else if (!cpu_has_perfctr_core)
 		offset = index;
 	else
 		offset = index << 1;
@@ -175,24 +198,36 @@ static inline int amd_pmu_addr_offset(int index, bool eventsel)
 
 static inline int amd_pmu_rdpmc_index(int index)
 {
-	return index;
-}
+	int ret, first;
 
-static int amd_pmu_hw_config(struct perf_event *event)
-{
-	int ret;
+	if (!index)
+		return index;
 
-	/* pass precise event sampling to ibs: */
-	if (event->attr.precise_ip && get_ibs_caps())
-		return -ENOENT;
+	ret = rdpmc_indexes[index];
 
-	ret = x86_pmu_hw_config(event);
 	if (ret)
 		return ret;
 
-	if (has_branch_stack(event))
-		return -EOPNOTSUPP;
+	if (amd_nb_event_constraint &&
+	    test_bit(index, amd_nb_event_constraint->idxmsk)) {
+		/*
+		 * according to the mnual, ECX value of the NB counters is
+		 * the index of the NB counter (0, 1, 2 or 3) plus 6
+		 */
+
+		first = find_first_bit(amd_nb_event_constraint->idxmsk,
+				       X86_PMC_IDX_MAX);
+		ret = index - first + 6;
+	} else
+		ret = index;
+
+	rdpmc_indexes[index] = ret;
 
+	return ret;
+}
+
+static int amd_core_hw_config(struct perf_event *event)
+{
 	if (event->attr.exclude_host && event->attr.exclude_guest)
 		/*
 		 * When HO == GO == 1 the hardware treats that as GO == HO == 0
@@ -206,10 +241,33 @@ static int amd_pmu_hw_config(struct perf_event *event)
 	else if (event->attr.exclude_guest)
 		event->hw.config |= AMD64_EVENTSEL_HOSTONLY;
 
-	if (event->attr.type != PERF_TYPE_RAW)
-		return 0;
+	return 0;
+}
 
-	event->hw.config |= event->attr.config & AMD64_RAW_EVENT_MASK;
+/*
+ * NB counters do not support the following event select bits:
+ *   Host/Guest only
+ *   Counter mask
+ *   Invert counter mask
+ *   Edge detect
+ *   OS/User mode
+ */
+static int amd_nb_hw_config(struct perf_event *event)
+{
+	/* for NB, we only allow system wide counting mode */
+	if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
+		return -EINVAL;
+
+	if (event->attr.exclude_user || event->attr.exclude_kernel ||
+	    event->attr.exclude_host || event->attr.exclude_guest)
+		return -EINVAL;
+
+	event->hw.config &= ~(ARCH_PERFMON_EVENTSEL_USR |
+			      ARCH_PERFMON_EVENTSEL_OS);
+
+	if (event->hw.config & ~(AMD64_RAW_EVENT_MASK_NB |
+				 ARCH_PERFMON_EVENTSEL_INT))
+		return -EINVAL;
 
 	return 0;
 }
@@ -227,6 +285,11 @@ static inline int amd_is_nb_event(struct hw_perf_event *hwc)
 	return (hwc->config & 0xe0) == 0xe0;
 }
 
+static inline int amd_is_perfctr_nb_event(struct hw_perf_event *hwc)
+{
+	return amd_nb_event_constraint && amd_is_nb_event(hwc);
+}
+
 static inline int amd_has_nb(struct cpu_hw_events *cpuc)
 {
 	struct amd_nb *nb = cpuc->amd_nb;
@@ -234,6 +297,30 @@ static inline int amd_has_nb(struct cpu_hw_events *cpuc)
 	return nb && nb->nb_id != -1;
 }
 
+static int amd_pmu_hw_config(struct perf_event *event)
+{
+	int ret;
+
+	/* pass precise event sampling to ibs: */
+	if (event->attr.precise_ip && get_ibs_caps())
+		return -ENOENT;
+
+	if (has_branch_stack(event))
+		return -EOPNOTSUPP;
+
+	ret = x86_pmu_hw_config(event);
+	if (ret)
+		return ret;
+
+	if (event->attr.type == PERF_TYPE_RAW)
+		event->hw.config |= event->attr.config & AMD64_RAW_EVENT_MASK;
+
+	if (amd_is_perfctr_nb_event(&event->hw))
+		return amd_nb_hw_config(event);
+
+	return amd_core_hw_config(event);
+}
+
 static void __amd_put_nb_event_constraints(struct cpu_hw_events *cpuc,
 					   struct perf_event *event)
 {
@@ -254,6 +341,19 @@ static void __amd_put_nb_event_constraints(struct cpu_hw_events *cpuc,
 	}
 }
 
+static void amd_nb_interrupt_hw_config(struct hw_perf_event *hwc)
+{
+	int core_id = cpu_data(smp_processor_id()).cpu_core_id;
+
+	/* deliver interrupts only to this core */
+	if (hwc->config & ARCH_PERFMON_EVENTSEL_INT) {
+		hwc->config |= AMD64_EVENTSEL_INT_CORE_ENABLE;
+		hwc->config &= ~AMD64_EVENTSEL_INT_CORE_SEL_MASK;
+		hwc->config |= (u64)(core_id) <<
+			AMD64_EVENTSEL_INT_CORE_SEL_SHIFT;
+	}
+}
+
  /*
   * AMD64 NorthBridge events need special treatment because
   * counter access needs to be synchronized across all cores
@@ -299,6 +399,12 @@ __amd_get_nb_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *ev
 	struct perf_event *old;
 	int idx, new = -1;
 
+	if (!c)
+		c = &unconstrained;
+
+	if (cpuc->is_fake)
+		return c;
+
 	/*
 	 * detect if already present, if so reuse
 	 *
@@ -335,6 +441,9 @@ __amd_get_nb_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *ev
 	if (new == -1)
 		return &emptyconstraint;
 
+	if (amd_is_perfctr_nb_event(hwc))
+		amd_nb_interrupt_hw_config(hwc);
+
 	return &nb->event_constraints[new];
 }
 
@@ -434,7 +543,8 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
 	if (!(amd_has_nb(cpuc) && amd_is_nb_event(&event->hw)))
 		return &unconstrained;
 
-	return __amd_get_nb_event_constraints(cpuc, event, &unconstrained);
+	return __amd_get_nb_event_constraints(cpuc, event,
+					      amd_nb_event_constraint);
 }
 
 static void amd_put_event_constraints(struct cpu_hw_events *cpuc,
@@ -533,6 +643,9 @@ static struct event_constraint amd_f15_PMC30 = EVENT_CONSTRAINT_OVERLAP(0, 0x09,
 static struct event_constraint amd_f15_PMC50 = EVENT_CONSTRAINT(0, 0x3F, 0);
 static struct event_constraint amd_f15_PMC53 = EVENT_CONSTRAINT(0, 0x38, 0);
 
+static struct event_constraint amd_NBPMC96 = EVENT_CONSTRAINT(0, 0x3C0, 0);
+static struct event_constraint amd_NBPMC74 = EVENT_CONSTRAINT(0, 0xF0, 0);
+
 static struct event_constraint *
 amd_get_event_constraints_f15h(struct cpu_hw_events *cpuc, struct perf_event *event)
 {
@@ -598,8 +711,8 @@ amd_get_event_constraints_f15h(struct cpu_hw_events *cpuc, struct perf_event *ev
 			return &amd_f15_PMC20;
 		}
 	case AMD_EVENT_NB:
-		/* not yet implemented */
-		return &emptyconstraint;
+		return __amd_get_nb_event_constraints(cpuc, event,
+						      amd_nb_event_constraint);
 	default:
 		return &emptyconstraint;
 	}
@@ -647,7 +760,7 @@ static __initconst const struct x86_pmu amd_pmu = {
 
 static int setup_event_constraints(void)
 {
-	if (boot_cpu_data.x86 >= 0x15)
+	if (boot_cpu_data.x86 == 0x15)
 		x86_pmu.get_event_constraints = amd_get_event_constraints_f15h;
 	return 0;
 }
@@ -677,6 +790,23 @@ static int setup_perfctr_core(void)
 	return 0;
 }
 
+static int setup_perfctr_nb(void)
+{
+	if (!cpu_has_perfctr_nb)
+		return -ENODEV;
+
+	x86_pmu.num_counters += AMD64_NUM_COUNTERS_NB;
+
+	if (cpu_has_perfctr_core)
+		amd_nb_event_constraint = &amd_NBPMC96;
+	else
+		amd_nb_event_constraint = &amd_NBPMC74;
+
+	printk(KERN_INFO "perf: AMD northbridge performance counters detected\n");
+
+	return 0;
+}
+
 __init int amd_pmu_init(void)
 {
 	/* Performance-monitoring supported from K7 and later: */
@@ -687,6 +817,7 @@ __init int amd_pmu_init(void)
 
 	setup_event_constraints();
 	setup_perfctr_core();
+	setup_perfctr_nb();
 
 	/* Events are common for all AMDs */
 	memcpy(hw_cache_event_ids, amd_hw_cache_event_ids,