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>

1 files changed, 151 insertions, 20 deletions

diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
index 05462f0432d5..dfdab42aed27 100644
--- a/arch/x86/kernel/cpu/perf_event_amd.c
+++ b/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,