path: root/drivers/perf/arm_spe_pmu.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Perf support for the Statistical Profiling Extension, introduced as
 * part of ARMv8.2.
 *
 * Copyright (C) 2016 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#define PMUNAME					"arm_spe"
#define DRVNAME					PMUNAME "_pmu"
#define pr_fmt(fmt)				DRVNAME ": " fmt

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/capability.h>
#include <linux/cpuhotplug.h>
#include <linux/cpumask.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/perf_event.h>
#include <linux/perf/arm_pmu.h>
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/vmalloc.h>

#include <asm/barrier.h>
#include <asm/cpufeature.h>
#include <asm/mmu.h>
#include <asm/sysreg.h>

/*
 * Cache if the event is allowed to trace Context information.
 * This allows us to perform the check, i.e, perfmon_capable(),
 * in the context of the event owner, once, during the event_init().
 */
#define SPE_PMU_HW_FLAGS_CX			0x00001

static_assert((PERF_EVENT_FLAG_ARCH & SPE_PMU_HW_FLAGS_CX) == SPE_PMU_HW_FLAGS_CX);

static void set_spe_event_has_cx(struct perf_event *event)
{
	if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && perfmon_capable())
		event->hw.flags |= SPE_PMU_HW_FLAGS_CX;
}

static bool get_spe_event_has_cx(struct perf_event *event)
{
	return !!(event->hw.flags & SPE_PMU_HW_FLAGS_CX);
}

#define ARM_SPE_BUF_PAD_BYTE			0

struct arm_spe_pmu_buf {
	int					nr_pages;
	bool					snapshot;
	void					*base;
};

struct arm_spe_pmu {
	struct pmu				pmu;
	struct platform_device			*pdev;
	cpumask_t				supported_cpus;
	struct hlist_node			hotplug_node;

	int					irq; /* PPI */
	u16					pmsver;
	u16					min_period;
	u16					counter_sz;

#define SPE_PMU_FEAT_FILT_EVT			(1UL << 0)
#define SPE_PMU_FEAT_FILT_TYP			(1UL << 1)
#define SPE_PMU_FEAT_FILT_LAT			(1UL << 2)
#define SPE_PMU_FEAT_ARCH_INST			(1UL << 3)
#define SPE_PMU_FEAT_LDS			(1UL << 4)
#define SPE_PMU_FEAT_ERND			(1UL << 5)
#define SPE_PMU_FEAT_INV_FILT_EVT		(1UL << 6)
#define SPE_PMU_FEAT_DEV_PROBED			(1UL << 63)
	u64					features;

	u16					max_record_sz;
	u16					align;
	struct perf_output_handle __percpu	*handle;
};

#define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))

/* Convert a free-running index from perf into an SPE buffer offset */
#define PERF_IDX2OFF(idx, buf)	((idx) % ((buf)->nr_pages << PAGE_SHIFT))

/* Keep track of our dynamic hotplug state */
static enum cpuhp_state arm_spe_pmu_online;

enum arm_spe_pmu_buf_fault_action {
	SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
	SPE_PMU_BUF_FAULT_ACT_FATAL,
	SPE_PMU_BUF_FAULT_ACT_OK,
};

/* This sysfs gunk was really good fun to write. */
enum arm_spe_pmu_capabilities {
	SPE_PMU_CAP_ARCH_INST = 0,
	SPE_PMU_CAP_ERND,
	SPE_PMU_CAP_FEAT_MAX,
	SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
	SPE_PMU_CAP_MIN_IVAL,
};

static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
	[SPE_PMU_CAP_ARCH_INST]	= SPE_PMU_FEAT_ARCH_INST,
	[SPE_PMU_CAP_ERND]	= SPE_PMU_FEAT_ERND,
};

static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
{
	if (cap < SPE_PMU_CAP_FEAT_MAX)
		return !!(spe_pmu->features & arm_spe_pmu_feat_caps[