Date:   Wed, 30 Aug 2017 10:54:03 +0800
From:   Zhangshaokun <zhangshaokun@...ilicon.com>
To:     Jan Glauber <jglauber@...ium.com>,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will.deacon@....com>
CC:     David Daney <david.daney@...ium.com>,
        Suzuki K Poulose <Suzuki.Poulose@....com>,
        <linux-kernel@...r.kernel.org>, Borislav Petkov <bp@...en8.de>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [RFC PATCH v9 5/7] perf: cavium: Support memory controller PMU
 counters

Hi Jan,

Some trivial things i noticed, please consider if you are glad.

Thanks,
Shaokun

On 2017/8/29 21:12, Jan Glauber wrote:
> 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/perf/Kconfig            |   8 +
>  drivers/perf/Makefile           |   1 +
>  drivers/perf/cavium_pmu.c       | 445 ++++++++++++++++++++++++++++++++++++++++
>  drivers/soc/cavium/cavium_lmc.c |   4 +
>  include/linux/cpuhotplug.h      |   1 +
>  include/linux/soc/cavium/lmc.h  |   3 +
>  6 files changed, 462 insertions(+)
>  create mode 100644 drivers/perf/cavium_pmu.c
> 
> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> index e5197ff..a787562 100644
> --- a/drivers/perf/Kconfig
> +++ b/drivers/perf/Kconfig
> @@ -43,4 +43,12 @@ config XGENE_PMU
>          help
>            Say y if you want to use APM X-Gene SoC performance monitors.
>  
> +config CAVIUM_PMU_LMC
> +	tristate "Cavium SOC memory controller PMU"
> +	depends on ARCH_THUNDER && m
> +	select CAVIUM_LMC
> +	help
> +	  Provides PMU counters for the memory controller on
> +	  Cavium ThunderX or OcteonTX SOCs.
> +
>  endmenu
> diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> index 6420bd4..077a15d 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_LMC) += cavium_pmu.o

Keep in alphabetic order?

> diff --git a/drivers/perf/cavium_pmu.c b/drivers/perf/cavium_pmu.c
> new file mode 100644
> index 0000000..bcdedaa
> --- /dev/null
> +++ b/drivers/perf/cavium_pmu.c
> @@ -0,0 +1,445 @@
> +/*
> + * 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/cpuhotplug.h>
> +#include <linux/io.h>
> +#include <linux/export.h>

Keep the include header files in alphabetic order too?

> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/pci.h>
> +#include <linux/perf_event.h>
> +#include <linux/slab.h>
> +#include <linux/soc/cavium/lmc.h>
> +
> +enum cvm_pmu_type {
> +	CVM_PMU_LMC,
> +};
> +
> +/* 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;

It seems that pmu_name is redundant since struct pmu has a name field,
Mark has mentioned it in HiSilicon uncore PMU driver, Link:
https://patchwork.kernel.org/patch/9861821/

> +	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;
> +};
> +
> +static struct list_head cvm_pmu_lmcs;
> +static struct list_head cvm_pmu_tlks;
> +
> +/*
> + * 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;

Blank line?

> +	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;

unsigned int?

> +
> +	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[] = {

Add const?

> +	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));
> +}
> +
> +int cvm_lmc_pmu_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> +{
> +	struct cvm_pmu_dev *next, *lmc;
> +	int nr = 0, ret = -ENOMEM;
> +
> +	lmc = kzalloc(sizeof(*lmc), GFP_KERNEL);

How about use devm_kzalloc?

> +	if (!lmc)
> +		return -ENOMEM;
> +
> +	lmc->map = ioremap(pci_resource_start(pdev, 0),
> +			   pci_resource_len(pdev, 0));
> +	if (!lmc->map)
> +		goto fail_ioremap;
> +
> +	list_for_each_entry(next, &cvm_pmu_lmcs, entry)
> +		nr++;
> +	lmc->pmu_name = kasprintf(GFP_KERNEL, "lmc%d", nr);

Use devm_kasprintf, simplify fail handle and memory free?

> +	if (!lmc->pmu_name)
> +		goto fail_kasprintf;
> +
> +	lmc->pdev = pdev;
> +	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);
> +
> +	list_add(&lmc->entry, &cvm_pmu_lmcs);
> +	lmc->event_valid = cvm_pmu_lmc_event_valid;
> +
> +	ret = perf_pmu_register(&lmc->pmu, lmc->pmu_name, -1);
> +	if (ret)
> +		goto fail_pmu;
> +
> +	dev_info(&pdev->dev, "Enabled %s PMU with %d counters\n",
> +		 lmc->pmu_name, lmc->num_counters);

Blank line?

> +	return 0;
> +
> +fail_pmu:
> +	kfree(lmc->pmu_name);
> +	cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> +				    &lmc->cpuhp_node);
> +fail_kasprintf:
> +	iounmap(lmc->map);
> +fail_ioremap:
> +	kfree(lmc);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(cvm_lmc_pmu_probe);
> +
> +void cvm_lmc_pmu_remove(struct pci_dev *pdev)
> +{
> +	struct list_head *l, *tmp;
> +	struct cvm_pmu_dev *lmc;
> +
> +	list_for_each_safe(l, tmp, &cvm_pmu_lmcs) {
> +		lmc = list_entry(l, struct cvm_pmu_dev, entry);
> +		if (pdev != lmc->pdev)
> +			continue;
> +
> +		perf_pmu_unregister(&lmc->pmu);
> +		iounmap(lmc->map);
> +		cpuhp_state_remove_instance(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> +					    &lmc->cpuhp_node);
> +		list_del(&lmc->entry);
> +		kfree(lmc->pmu_name);
> +		kfree(lmc);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(cvm_lmc_pmu_remove);
> +
> +static int __init cvm_pmu_init(void)
> +{
> +	INIT_LIST_HEAD(&cvm_pmu_lmcs);
> +	INIT_LIST_HEAD(&cvm_pmu_tlks);
> +
> +	return cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_CVM_ONLINE,
> +				       "perf/arm/cvm:online", NULL,
> +				       cvm_pmu_offline_cpu);
> +}
> +
> +static void __exit cvm_pmu_exit(void)
> +{
> +	cpuhp_remove_multi_state(CPUHP_AP_PERF_ARM_CVM_ONLINE);
> +}
> +
> +module_init(cvm_pmu_init);
> +module_exit(cvm_pmu_exit);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Cavium, Inc.");
> +MODULE_DESCRIPTION("PMU Driver for Cavium ThunderX SOC");
> diff --git a/drivers/soc/cavium/cavium_lmc.c b/drivers/soc/cavium/cavium_lmc.c
> index 87248e8..d21d59c 100644
> --- a/drivers/soc/cavium/cavium_lmc.c
> +++ b/drivers/soc/cavium/cavium_lmc.c
> @@ -17,6 +17,8 @@
>  static int cvm_lmc_probe(struct pci_dev *pdev,
>  			 const struct pci_device_id *ent)
>  {
> +	if (IS_ENABLED(CONFIG_CAVIUM_PMU_LMC))
> +		cvm_lmc_pmu_probe(pdev, ent);
>  	if (IS_ENABLED(CONFIG_EDAC_THUNDERX))
>  		thunderx_edac_lmc_probe(pdev, ent);
>  	return 0;
> @@ -24,6 +26,8 @@ static int cvm_lmc_probe(struct pci_dev *pdev,
>  
>  static void cvm_lmc_remove(struct pci_dev *pdev)
>  {
> +	if (IS_ENABLED(CONFIG_CAVIUM_PMU_LMC))
> +		cvm_lmc_pmu_remove(pdev);
>  	if (IS_ENABLED(CONFIG_EDAC_THUNDERX))
>  		thunderx_edac_lmc_remove(pdev);
>  }
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index 82b30e6..ca84ac8 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -139,6 +139,7 @@ enum cpuhp_state {
>  	CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
>  	CPUHP_AP_WORKQUEUE_ONLINE,
>  	CPUHP_AP_RCUTREE_ONLINE,
> +	CPUHP_AP_PERF_ARM_CVM_ONLINE,

Alphabetic order?

>  	CPUHP_AP_ONLINE_DYN,
>  	CPUHP_AP_ONLINE_DYN_END		= CPUHP_AP_ONLINE_DYN + 30,
>  	CPUHP_AP_X86_HPET_ONLINE,
> diff --git a/include/linux/soc/cavium/lmc.h b/include/linux/soc/cavium/lmc.h
> index 336f467..e5ad650 100644
> --- a/include/linux/soc/cavium/lmc.h
> +++ b/include/linux/soc/cavium/lmc.h
> @@ -3,6 +3,9 @@
>  
>  #include <linux/pci.h>
>  
> +int cvm_lmc_pmu_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
> +void cvm_lmc_pmu_remove(struct pci_dev *pdev);
> +
>  int thunderx_edac_lmc_probe(struct pci_dev *pdev, const struct pci_device_id *ent);
>  void thunderx_edac_lmc_remove(struct pci_dev *pdev);
>  
> 

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