[PATCH 2/3] perf/x86/amd/uncore: Dynamically allocate uncore counters

[Janakarajan Natarajan]

This patch updates the AMD uncore driver to support AMD Family17h
processors. In Family17h, there are two extra last level cache counters.
The counters are, therefore, allocated dynamically based on the family.

The cpu hotplug up callback function is refactored to better manage
failure conditions.

Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@xxxxxxx>
---
 arch/x86/events/amd/uncore.c | 141 +++++++++++++++++++++++++++++++------------
 1 file changed, 104 insertions(+), 37 deletions(-)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index 24c8537..7ab92f7 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -22,13 +22,16 @@
 
 #define NUM_COUNTERS_NB		4
 #define NUM_COUNTERS_L2		4
-#define MAX_COUNTERS		NUM_COUNTERS_NB
+#define NUM_COUNTERS_L3		6
 
 #define RDPMC_BASE_NB		6
 #define RDPMC_BASE_LLC		10
 
 #define COUNTER_SHIFT		16
 
+static int num_counters_llc;
+static int num_counters_nb;
+
 static HLIST_HEAD(uncore_unused_list);
 
 struct amd_uncore {
@@ -40,7 +43,7 @@ struct amd_uncore {
 	u32 msr_base;
 	cpumask_t *active_mask;
 	struct pmu *pmu;
-	struct perf_event *events[MAX_COUNTERS];
+	struct perf_event **events;
 	struct hlist_node node;
 };
 
@@ -123,6 +126,9 @@ static int amd_uncore_add(struct perf_event *event, int flags)
 	struct amd_uncore *uncore = event_to_amd_uncore(event);
 	struct hw_perf_event *hwc = &event->hw;
 
+	if (hwc->idx >= uncore->num_counters)
+		return -EINVAL;
+
 	/* are we already assigned? */
 	if (hwc->idx != -1 && uncore->events[hwc->idx] == event)
 		goto out;
@@ -288,51 +294,91 @@ static struct pmu amd_llc_pmu = {
 	.read		= amd_uncore_read,
 };
 
-static struct amd_uncore *amd_uncore_alloc(unsigned int cpu)
+static struct amd_uncore *amd_uncore_alloc(unsigned int cpu,
+					unsigned int counters)
 {
-	return kzalloc_node(sizeof(struct amd_uncore), GFP_KERNEL,
+	void *mem;
+	struct amd_uncore *uncore;
+
+	mem = kzalloc_node(sizeof(struct amd_uncore) +
+			sizeof(struct perf_event*) * counters, GFP_KERNEL,
 			cpu_to_node(cpu));
+	if (!mem)
+		return NULL;
+
+	uncore = mem;
+	uncore->events = mem + sizeof(struct amd_uncore);
+
+	return uncore;
 }
 
-static int amd_uncore_cpu_up_prepare(unsigned int cpu)
+static int amd_uncore_cpu_up_nb_prepare(unsigned int cpu)
 {
-	struct amd_uncore *uncore_nb = NULL, *uncore_llc;
+	struct amd_uncore *uncore_nb;
 
-	if (amd_uncore_nb) {
-		uncore_nb = amd_uncore_alloc(cpu);
-		if (!uncore_nb)
-			goto fail;
-		uncore_nb->cpu = cpu;
-		uncore_nb->num_counters = NUM_COUNTERS_NB;
-		uncore_nb->rdpmc_base = RDPMC_BASE_NB;
-		uncore_nb->msr_base = MSR_F15H_NB_PERF_CTL;
-		uncore_nb->active_mask = &amd_nb_active_mask;
-		uncore_nb->pmu = &amd_nb_pmu;
-		uncore_nb->id = -1;
-		*per_cpu_ptr(amd_uncore_nb, cpu) = uncore_nb;
-	}
+	if (!amd_uncore_nb)
+		return 0;
 
-	if (amd_uncore_llc) {
-		uncore_llc = amd_uncore_alloc(cpu);
-		if (!uncore_llc)
-			goto fail;
-		uncore_llc->cpu = cpu;
-		uncore_llc->num_counters = NUM_COUNTERS_L2;
-		uncore_llc->rdpmc_base = RDPMC_BASE_LLC;
-		uncore_llc->msr_base = MSR_F16H_L2I_PERF_CTL;
-		uncore_llc->active_mask = &amd_llc_active_mask;
-		uncore_llc->pmu = &amd_llc_pmu;
-		uncore_llc->id = -1;
-		*per_cpu_ptr(amd_uncore_llc, cpu) = uncore_llc;
-	}
+	uncore_nb = amd_uncore_alloc(cpu, num_counters_nb);
+	if (!uncore_nb)
+		return -ENOMEM;
+	uncore_nb->cpu = cpu;
+	uncore_nb->num_counters = num_counters_nb;
+	uncore_nb->rdpmc_base = RDPMC_BASE_NB;
+	uncore_nb->msr_base = MSR_F15H_NB_PERF_CTL;
+	uncore_nb->active_mask = &amd_nb_active_mask;
+	uncore_nb->pmu = &amd_nb_pmu;
+	uncore_nb->id = -1;
+	*per_cpu_ptr(amd_uncore_nb, cpu) = uncore_nb;
 
 	return 0;
+}
 
-fail:
-	if (amd_uncore_nb)
-		*per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
-	kfree(uncore_nb);
-	return -ENOMEM;
+static int amd_uncore_cpu_up_llc_prepare(unsigned int cpu)
+{
+	struct amd_uncore *uncore_llc;
+
+	if (!amd_uncore_llc)
+		return 0;
+
+	uncore_llc = amd_uncore_alloc(cpu, num_counters_llc);
+	if (!uncore_llc)
+		return -ENOMEM;
+	uncore_llc->cpu = cpu;
+	uncore_llc->num_counters = num_counters_llc;
+	uncore_llc->rdpmc_base = RDPMC_BASE_LLC;
+	uncore_llc->msr_base = MSR_F16H_L2I_PERF_CTL;
+	uncore_llc->active_mask = &amd_llc_active_mask;
+	uncore_llc->pmu = &amd_llc_pmu;
+	uncore_llc->id = -1;
+	*per_cpu_ptr(amd_uncore_llc, cpu) = uncore_llc;
+
+	return 0;
+}
+
+static void amd_uncore_cpu_up_nb_free(unsigned int cpu)
+{
+	struct amd_uncore *uncore_nb;
+
+	uncore_nb = *per_cpu_ptr(amd_uncore_nb, cpu);
+	if (uncore_nb)
+		kfree(uncore_nb);
+	*per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
+}
+
+static int amd_uncore_cpu_up_prepare(unsigned int cpu)
+{
+	int ret;
+
+	ret = amd_uncore_cpu_up_nb_prepare(cpu);
+	if (ret)
+		return ret;
+	ret = amd_uncore_cpu_up_llc_prepare(cpu);
+	if (ret) {
+		amd_uncore_cpu_up_nb_free(cpu);
+		return ret;
+	}
+	return 0;
 }
 
 static struct amd_uncore *
@@ -492,6 +538,27 @@ static int __init amd_uncore_init(void)
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
 		goto fail_nodev;
 
+	switch(boot_cpu_data.x86) {
+		case 23:
+			/* Family 17h */
+			num_counters_nb = NUM_COUNTERS_NB;
+			num_counters_llc = NUM_COUNTERS_L3;
+			break;
+		case 22:
+			/* Family 16h. May change */
+			num_counters_nb = NUM_COUNTERS_NB;
+			num_counters_llc = NUM_COUNTERS_L2;
+			break;
+		default:
+			/*
+			 * All prior families have the same number of
+			 * Northbridge and Last level cache counters
+			 */
+			num_counters_nb = NUM_COUNTERS_NB;
+			num_counters_llc = NUM_COUNTERS_L2;
+			break;
+	}
+
 	if (!boot_cpu_has(X86_FEATURE_TOPOEXT))
 		goto fail_nodev;
 
-- 
2.7.4