Message-Id: <20170623130128.11006-2-jglauber@cavium.com>
Date:   Fri, 23 Jun 2017 15:01:26 +0200
From:   Jan Glauber <jglauber@...ium.com>
To:     Mark Rutland <mark.rutland@....com>
Cc:     Will Deacon <will.deacon@....com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Borislav Petkov <bp@...en8.de>,
        Jan Glauber <jglauber@...ium.com>
Subject: [PATCH v6 1/3] perf: cavium: Support memory controller PMU counters

Add support for the PMU counters on Cavium SOC memory controllers.

This patch also adds generic functions to allow supporting more
devices with PMU counters.

Properties of the LMC PMU counters:
- not stoppable
- fixed purpose
- read-only
- one PCI device per memory controller

Signed-off-by: Jan Glauber <jglauber@...ium.com>
---
 drivers/edac/thunderx_edac.c    |   7 +-
 drivers/perf/Kconfig            |   9 +
 drivers/perf/Makefile           |   1 +
 drivers/perf/cavium_pmu.c       | 418 ++++++++++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h      |   1 +
 include/linux/perf/cavium_pmu.h |  53 +++++
 6 files changed, 488 insertions(+), 1 deletion(-)
 create mode 100644 drivers/perf/cavium_pmu.c
 create mode 100644 include/linux/perf/cavium_pmu.h

diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index 86d585c..884499a 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -20,7 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/bitfield.h>
 #include <linux/circ_buf.h>
-
+#include <linux/perf/cavium_pmu.h>
 #include <asm/page.h>
 
 #include "edac_module.h"
@@ -209,6 +209,8 @@ struct thunderx_lmc {
 	struct lmc_err_ctx err_ctx[RING_ENTRIES];
 	unsigned long ring_head;
 	unsigned long ring_tail;
+
+	void *pmu_data;
 };
 
 #define ring_pos(pos, size) ((pos) & (size - 1))
@@ -810,6 +812,7 @@ static int thunderx_lmc_probe(struct pci_dev *pdev,
 		}
 	}
 
+	lmc->pmu_data = cvm_pmu_probe(pdev, lmc->regs, CVM_PMU_LMC);
 	return 0;
 
 err_free:
@@ -824,6 +827,8 @@ static void thunderx_lmc_remove(struct pci_dev *pdev)
 	struct mem_ctl_info *mci = pci_get_drvdata(pdev);
 	struct thunderx_lmc *lmc = mci->pvt_info;
 
+	cvm_pmu_remove(pdev, lmc->pmu_data, CVM_PMU_LMC);
+
 	writeq(LMC_INT_ENA_ALL, lmc->regs + LMC_INT_ENA_W1C);
 
 	edac_mc_del_mc(&pdev->dev);
diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index aa587ed..bd0d89f 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -42,4 +42,13 @@ config XGENE_PMU
         help
           Say y if you want to use APM X-Gene SoC performance monitors.
 
+config CAVIUM_PMU
+	bool "Cavium SOC PMU"
+	default y
+	depends on EDAC_THUNDERX && PERF_EVENTS
+	help
+	  Provides access to various performance counters on Caviums
+	  ARM64 SOCs. Adds support for memory controller (LMC) and
+	  interconnect link (OCX TLK) counters.
+
 endmenu
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index 6420bd4..b304646 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
 obj-$(CONFIG_QCOM_L2_PMU)	+= qcom_l2_pmu.o
 obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
 obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
+obj-$(CONFIG_CAVIUM_PMU) += cavium_pmu.o
diff --git a/drivers/perf/cavium_pmu.c b/drivers/perf/cavium_pmu.c
new file mode 100644
index 0000000..4a85c7fac
--- /dev/null
+++ b/drivers/perf/cavium_pmu.c
@@ -0,0 +1,418 @@
+/*
+ * Cavium ARM SOC "uncore" PMU counters
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright Cavium, Inc. 2017
+ * Author(s): Jan Glauber <jan.glauber@...ium.com>
+ *
+ */
+#include <linux/cpumask.h>
+#include <linux/export.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+
+#include <linux/perf/cavium_pmu.h>
+
+static bool cvm_pmu_initialized;
+static struct list_head cvm_pmu_lmcs;
+
+/*
+ * Common Cavium PMU stuff
+ *
+ * Shared properties of the different PMU types:
+ * - all counters are 64 bit long
+ * - there are no overflow interrupts
+ * - all devices with PMU counters appear as PCI devices
+ *
+ * Counter control, access and device association depends on the
+ * PMU type.
+ */
+
+#define to_pmu_dev(x) container_of((x), struct cvm_pmu_dev, pmu)
+
+static int cvm_pmu_event_init(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct cvm_pmu_dev *pmu_dev;
+	struct perf_event *sibling;
+
+	if (event->attr.type != event->pmu->type)
+		return -ENOENT;
+
+	/* we do not support sampling */
+	if (is_sampling_event(event))
+		return -EINVAL;
+
+	/* PMU counters do not support any these bits */
+	if (event->attr.exclude_user	||
+	    event->attr.exclude_kernel	||
+	    event->attr.exclude_host	||
+	    event->attr.exclude_guest	||
+	    event->attr.exclude_hv	||
+	    event->attr.exclude_idle)
+		return -EINVAL;
+
+	pmu_dev = to_pmu_dev(event->pmu);
+	if (!pmu_dev->event_valid(event->attr.config))
+		return -EINVAL;
+
+	/*
+	 * Forbid groups containing mixed PMUs, software events are acceptable.
+	 */
+	if (event->group_leader->pmu != event->pmu &&
+			!is_software_event(event->group_leader))
+		return -EINVAL;
+
+	list_for_each_entry(sibling, &event->group_leader->sibling_list,
+			group_entry)
+		if (sibling->pmu != event->pmu &&
+				!is_software_event(sibling))
+			return -EINVAL;
+
+	hwc->config = event->attr.config;
+	hwc->idx = -1;
+	return 0;
+}
+
+static void cvm_pmu_read(struct perf_event *event)
+{
+	struct cvm_pmu_dev *pmu_dev = to_pmu_dev(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 prev, delta, new;
+
+again:
+	prev = local64_read(&hwc->prev_count);
+	new = readq(hwc->event_base + pmu_dev->map);
+
+	if (local64_cmpxchg(&hwc->prev_count, prev, new) != prev)
+		goto again;
+
+	delta = new - prev;
+	local64_add(delta, &event->count);
+}
+
+static void cvm_pmu_start(struct perf_event *event, int flags)
+{
+	struct cvm_pmu_dev *pmu_dev = to_pmu_dev(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 new;
+
+	if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
+		return;
+
+	WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
+	hwc->state = 0;
+
+	/* update prev_count always in order support unstoppable counters */
+	new = readq(hwc->event_base + pmu_dev->map);
+	local64_set(&hwc->prev_count, new);
+
+	perf_event_update_userpage(event);
+}
+
+static void cvm_pmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
+	hwc->state |= PERF_HES_STOPPED;
+
+	if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+		cvm_pmu_read(event);
+		hwc->state |= PERF_HES_UPTODATE;
+	}
+}
+
+static int cvm_pmu_add(struct perf_event *event, int flags, u64 config_base,
+		       u64 event_base)
+{
+	struct cvm_pmu_dev *pmu_dev = to_pmu_dev(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (!cmpxchg(&pmu_dev->events[hwc->config], NULL, event))
+		hwc->idx = hwc->config;
+
+	if (hwc->idx == -1)
+		return -EBUSY;
+
+	hwc->config_base = config_base;
+	hwc->event_base = event_base;
+	hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+	if (flags & PERF_EF_START)
+		pmu_dev->pmu.start(event, PERF_EF_RELOAD);
+
+	return 0;
+}
+
+static void cvm_pmu_del(struct perf_event *event, int flags)
+{
+	struct cvm_pmu_dev *pmu_dev = to_pmu_dev(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	int i;
+
+	event->pmu->stop(event, PERF_EF_UPDATE);
+
+	/*
+	 * For programmable counters we need to check where we installed it.
+	 * To keep this function generic always test the more complicated
+	 * case (free running counters won't need the loop).
+	 */
+	for (i = 0; i < pmu_dev->num_counters; i++)
+		if (cmpxchg(&pmu_dev->events[i], event, NULL) == event)
+			break;
+
+	perf_event_update_userpage(event);
+	hwc->idx = -1;
+}
+
+static ssize_t cvm_pmu_event_sysfs_show(struct device *dev,
+					struct device_attribute *attr,
+					char *page)
+{
+	struct perf_pmu_events_attr *pmu_attr =
+		container_of(attr, struct perf_pmu_events_attr, attr);
+
+	if (pmu_attr->event_str)
+		return sprintf(page, "%s", pmu_attr->event_str);
+
+	return 0;
+}
+
+/*
+ * The pmu events are independent from CPUs. Provide a cpumask
+ * nevertheless to prevent perf from adding the event per-cpu and just
+ * set the mask to one online CPU. Use the same cpumask for all "uncore"
+ * devices.
+ *
+ * There is a performance penalty for accessing a device from a CPU on
+ * another socket, but we do not care.
+ */
+static int cvm_pmu_offline_cpu(unsigned int old_cpu, struct hlist_node *node)
+{
+	struct cvm_pmu_dev *pmu_dev;
+	int new_cpu;
+
+	pmu_dev = hlist_entry_safe(node, struct cvm_pmu_dev, cpuhp_node);
+	if (!cpumask_test_and_clear_cpu(old_cpu, &pmu_dev->active_mask))
+		return 0;
+
+	new_cpu = cpumask_any_but(cpu_online_mask, old_cpu);
+	if (new_cpu >= nr_cpu_ids)
+		return 0;
+	perf_pmu_migrate_context(&pmu_dev->pmu, old_cpu, new_cpu);
+	cpumask_set_cpu(new_cpu, &pmu_dev->active_mask);
+	return 0;
+}
+
+static ssize_t cvm_pmu_attr_show_cpumask(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct pmu *pmu = dev_get_drvdata(dev);
+	struct cvm_pmu_dev *pmu_dev = container_of(pmu, struct cvm_pmu_dev, pmu);
+
+	return cpumap_print_to_pagebuf(true, buf, &pmu_dev->active_mask);
+}
+
+static DEVICE_ATTR(cpumask, S_IRUGO, cvm_pmu_attr_show_cpumask, NULL);
+
+static struct attribute *cvm_pmu_attrs[] = {
+	&dev_attr_cpumask.attr,
+	NULL,
+};
+
+static struct attribute_group cvm_pmu_attr_group = {
+	.attrs = cvm_pmu_attrs,
+};
+
+/*
+ * LMC (memory controller) counters:
+ * - not stoppable, always on, read-only
+ * - one PCI device per memory controller
+ */
+#define LMC_CONFIG_OFFSET		0x188
+#define LMC_CONFIG_RESET_BIT		BIT(17)
+
+/* LMC events */
+#define LMC_EVENT_IFB_CNT		0x1d0
+#define LMC_EVENT_OPS_CNT		0x1d8
+#define LMC_EVENT_DCLK_CNT		0x1e0
+#define LMC_EVENT_BANK_CONFLICT1	0x360
+#define LMC_EVENT_BANK_CONFLICT2	0x368
+
+#define CVM_PMU_LMC_EVENT_ATTR(_name, _id)						\
+	&((struct perf_pmu_events_attr[]) {						\
+		{									\
+			__ATTR(_name, S_IRUGO, cvm_pmu_event_sysfs_show, NULL),		\
+			_id,								\
+			"lmc_event=" __stringify(_id),					\
+		}									\
+	})[0].attr.attr
+
+/* map counter numbers to register offsets */
+static int lmc_events[] = {
+	LMC_EVENT_IFB_CNT,
+	LMC_EVENT_OPS_CNT,
+	LMC_EVENT_DCLK_CNT,
+	LMC_EVENT_BANK_CONFLICT1,
+	LMC_EVENT_BANK_CONFLICT2,
+};
+
+static int cvm_pmu_lmc_add(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	return cvm_pmu_add(event, flags, LMC_CONFIG_OFFSET,
+			   lmc_events[hwc->config]);
+}
+
+PMU_FORMAT_ATTR(lmc_event, "config:0-2");
+
+static struct attribute *cvm_pmu_lmc_format_attr[] = {
+	&format_attr_lmc_event.attr,
+	NULL,
+};
+
+static struct attribute_group cvm_pmu_lmc_format_group = {
+	.name = "format",
+	.attrs = cvm_pmu_lmc_format_attr,
+};
+
+static struct attribute *cvm_pmu_lmc_events_attr[] = {
+	CVM_PMU_LMC_EVENT_ATTR(ifb_cnt,		0),
+	CVM_PMU_LMC_EVENT_ATTR(ops_cnt,		1),
+	CVM_PMU_LMC_EVENT_ATTR(dclk_cnt,	2),
+	CVM_PMU_LMC_EVENT_ATTR(bank_conflict1,	3),
+	CVM_PMU_LMC_EVENT_ATTR(bank_conflict2,	4),
+	NULL,
+};
+
+static struct attribute_group cvm_pmu_lmc_events_group = {
+	.name = "events",
+	.attrs = cvm_pmu_lmc_events_attr,
+};
+
+static const struct attribute_group *cvm_pmu_lmc_attr_groups[] = {
+	&cvm_pmu_attr_group,
+	&cvm_pmu_lmc_format_group,
+	&cvm_pmu_lmc_events_group,
+	NULL,
+};
+
+static bool cvm_pmu_lmc_event_valid(u64 config)
+{
+	return (config < ARRAY_SIZE(lmc_events));
+}
+
+static void *cvm_pmu_lmc_probe(struct pci_dev *pdev, void __iomem *regs)
+{
+	struct cvm_pmu_dev *next, *lmc;
+	int nr = 0, ret = -ENOMEM;
+
+	lmc = kzalloc(sizeof(*lmc), GFP_KERNEL);
+	if (!lmc)
+		goto fail_nomem;
+
+	list_for_each_entry(next, &cvm_pmu_lmcs, entry)
+		nr++;
+	lmc->pmu_name = kasprintf(GFP_KERNEL, "lmc%d", nr);
+
+	lmc->pdev = pdev;
+	lmc->map = regs;
+	lmc->num_counters = ARRAY_SIZE(lmc_events);
+	lmc->pmu = (struct pmu) {
+		.task_ctx_nr    = perf_invalid_context,
+		.event_init	= cvm_pmu_event_init,
+		.add		= cvm_pmu_lmc_add,
+		.del		= cvm_pmu_del,
+		.start		= cvm_pmu_start,
+		.stop		= cvm_pmu_stop,
+		.read		= cvm_pmu_read,
+		.attr_groups	= cvm_pmu_lmc_attr_groups,
+	};
+
+	cpuhp_state_add_instance_nocalls(CPUHP_AP_PERF_ARM_CVM_ONLINE,
+					 &lmc->cpuhp_node);
+
+	/*
+	 * perf PMU is CPU dependent so pick a random CPU and migrate away
+	 * if it goes offline.
+	 */
+	cpumask_set_cpu(smp_processor_id(), &lmc->active_mask);
+
+	ret = perf_pmu_register(&lmc->pmu, lmc->pmu_name, -1);
+	if (ret)
+		goto fail_hp;
+
+	list_add(&lmc->entry, &cvm_pmu_lmcs);
+
+	lmc->event_valid = cvm_pmu_lmc_event_valid;
+	dev_info(&pdev->dev, "Enabled %s PMU with %d counters\n",
+		 lmc->pmu_name, lmc->num_counters);
+	return lmc;
+
+fail_hp:
+	kfree(lmc->pmu_name);
+	cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_CVM_ONLINE,
+				    &lmc->cpuhp_node);
+	kfree(lmc);
+fail_nomem:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(cvm_pmu_lmc_probe);
+
+static void cvm_pmu_lmc_remove(struct pci_dev *pdev, void *pmu_data)
+{
+	struct cvm_pmu_dev *lmc = (struct cvm_pmu_dev *) pmu_data;
+
+	cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_CVM_ONLINE,
+				    &lmc->cpuhp_node);
+	list_del(&lmc->entry);
+	perf_pmu_unregister(&lmc->pmu);
+	kfree(lmc->pmu_name);
+	kfree(lmc);
+}
+EXPORT_SYMBOL_GPL(cvm_pmu_lmc_remove);
+
+static int cvm_pmu_init(void)
+{
+	if (cvm_pmu_initialized)
+		return 0;
+
+	INIT_LIST_HEAD(&cvm_pmu_lmcs);
+
+	return cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_CVM_ONLINE,
+				       "perf/arm/cvm:online", NULL,
+				       cvm_pmu_offline_cpu);
+}
+
+void *cvm_pmu_probe(struct pci_dev *pdev, void __iomem *regs, int type)
+{
+	if (!cvm_pmu_initialized) {
+		cvm_pmu_init();
+		cvm_pmu_initialized = true;
+	}
+
+	switch (type) {
+	case CVM_PMU_LMC:
+		return cvm_pmu_lmc_probe(pdev, regs);
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(cvm_pmu_probe);
+
+void cvm_pmu_remove(struct pci_dev *pdev, void *pmu_data, int type)
+{
+	switch (type) {
+	case CVM_PMU_LMC:
+		return cvm_pmu_lmc_remove(pdev, pmu_data);
+	}
+}
+EXPORT_SYMBOL_GPL(cvm_pmu_remove);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 0f2a803..2fe906c 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -141,6 +141,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
 	CPUHP_AP_WORKQUEUE_ONLINE,
 	CPUHP_AP_RCUTREE_ONLINE,
+	CPUHP_AP_PERF_ARM_CVM_ONLINE,
 	CPUHP_AP_ONLINE_DYN,
 	CPUHP_AP_ONLINE_DYN_END		= CPUHP_AP_ONLINE_DYN + 30,
 	CPUHP_AP_X86_HPET_ONLINE,
diff --git a/include/linux/perf/cavium_pmu.h b/include/linux/perf/cavium_pmu.h
new file mode 100644
index 0000000..6ddc1c6
--- /dev/null
+++ b/include/linux/perf/cavium_pmu.h
@@ -0,0 +1,53 @@
+#ifndef _CAVIUM_PMU_H
+#define _CAVIUM_PMU_H
+
+#include <linux/io.h>
+#include <linux/pci.h>
+
+enum cvm_pmu_type {
+	CVM_PMU_LMC,
+};
+
+#ifdef CONFIG_CAVIUM_PMU
+
+#include <linux/cpumask.h>
+#include <linux/list.h>
+#include <linux/perf_event.h>
+
+/* maximum number of parallel hardware counters for all pmu types */
+#define CVM_PMU_MAX_COUNTERS 64
+
+/* generic struct to cover the different pmu types */
+struct cvm_pmu_dev {
+	struct pmu pmu;
+	const char *pmu_name;
+	bool (*event_valid)(u64);
+	void __iomem *map;
+	struct pci_dev *pdev;
+	int num_counters;
+	struct perf_event *events[CVM_PMU_MAX_COUNTERS];
+	struct list_head entry;
+	struct hlist_node cpuhp_node;
+	cpumask_t active_mask;
+};
+
+
+/* PMU interface used by EDAC driver */
+void *cvm_pmu_probe(struct pci_dev *pdev, void __iomem *regs, int type);
+void cvm_pmu_remove(struct pci_dev *pdev, void *pmu_data, int type);
+
+#else
+static inline void *cvm_pmu_probe(struct pci_dev *pdev, void __iomem *regs,
+				  int type)
+{
+	return NULL;
+}
+
+static inline void cvm_pmu_remove(struct pci_dev *pdev, void *pmu_data,
+				  int type)
+{
+}
+
+#endif
+
+#endif
-- 
2.9.0.rc0.21.g7777322

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