perf: arm: Implement perf counter for 32bit arm (14d7d371) · Commits · e / devices / android_kernel_fairphone_FP5

arch/arm/kernel/Makefile

+2 −1

Original line number	Diff line number	Diff line
		@@ -78,7 +78,8 @@ obj-$(CONFIG_CPU_PJ4B) += pj4-cp0.o
		obj-$(CONFIG_IWMMXT) += iwmmxt.o
		obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o
		obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_xscale.o perf_event_v6.o \
		perf_event_v7.o
		perf_event_v7.o perf_trace_counters.o

		AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt
		obj-$(CONFIG_ARM_CPU_TOPOLOGY) += topology.o
		obj-$(CONFIG_VDSO) += vdso.o

arch/arm/kernel/perf_trace_counters.c

0 → 100644

+179 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* Copyright (c) 2021, Qualcomm Innovation Center, Inc. All rights reserved.
		*/

		#include <linux/uaccess.h>
		#include <linux/debugfs.h>
		#include <linux/cpu.h>
		#include <linux/tracepoint.h>
		#include <trace/events/sched.h>
		#define CREATE_TRACE_POINTS
		#include "perf_trace_counters.h"

		static unsigned int tp_pid_state;

		DEFINE_PER_CPU(u32, cntenset_val);
		DEFINE_PER_CPU(u32, previous_ccnt);
		DEFINE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);
		DEFINE_PER_CPU(u32, old_pid);
		DEFINE_PER_CPU(u32, hotplug_flag);

		#define USE_CPUHP_STATE CPUHP_AP_ONLINE

		static int tracectr_cpu_hotplug_coming_up(unsigned int cpu)
		{
		per_cpu(hotplug_flag, cpu) = 1;

		return 0;
		}

		static void setup_prev_cnts(u32 cpu, u32 cnten_val)
		{
		int i;

		if (cnten_val & CC) {
		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"
		(per_cpu(previous_ccnt, cpu)));
		}
		for (i = 0; i < NUM_L1_CTRS; i++) {
		if (cnten_val & (1 << i)) {
		/* Select */
		asm volatile("mcr p15, 0, %0, c9, c12, 5" : : "r" (i));
		isb();
		/* Read value */
		asm volatile("mrc p15, 0, %0, c9, c13, 2" : "=r"
		(per_cpu(previous_l1_cnts[i], cpu)));
		}
		}
		}

		void tracectr_notifier(void *ignore, bool preempt,
		struct task_struct prev, struct task_struct next)
		{
		u32 cnten_val;
		int current_pid;
		u32 cpu = task_cpu(next);

		if (tp_pid_state != 1)
		return;
		current_pid = next->pid;
		if (per_cpu(old_pid, cpu) != -1) {
		/* Read PMCNTENSET */
		asm volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"
		(cnten_val));
		per_cpu(cntenset_val, cpu) = cnten_val;
		/* Disable all the counters that were enabled */
		asm volatile("mcr p15, 0, %0, c9, c12, 2" : : "r"
		(cnten_val));

		if (per_cpu(hotplug_flag, cpu) == 1) {
		per_cpu(hotplug_flag, cpu) = 0;
		setup_prev_cnts(cpu, cnten_val);
		} else {
		trace_sched_switch_with_ctrs(per_cpu(old_pid, cpu),
		current_pid);
		}
		/* Enable all the counters that were disabled + CCNTR each time*/
		asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r" (cnten_val \| CC));
		}
		per_cpu(old_pid, cpu) = current_pid;
		}

		static void enable_tp_pid(void)
		{
		if (tp_pid_state == 0) {
		tp_pid_state = 1;
		register_trace_sched_switch(tracectr_notifier, NULL);
		}
		}

		static void disable_tp_pid(void)
		{
		if (tp_pid_state == 1) {
		tp_pid_state = 0;
		unregister_trace_sched_switch(tracectr_notifier, NULL);
		}
		}

		static ssize_t read_enabled_perftp_file_bool(struct file *file,
		char __user user_buf, size_t count, loff_t ppos)
		{
		char buf[2];

		buf[1] = '\n';
		if (tp_pid_state == 0)
		buf[0] = '0';
		else
		buf[0] = '1';
		return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
		}

		static ssize_t write_enabled_perftp_file_bool(struct file *file,
		const char __user user_buf, size_t count, loff_t ppos)
		{
		char buf[32];
		size_t buf_size;

		buf[0] = 0;
		buf_size = min(count, (sizeof(buf)-1));
		if (copy_from_user(buf, user_buf, buf_size))
		return -EFAULT;
		switch (buf[0]) {
		case 'y':
		case 'Y':
		case '1':
		enable_tp_pid();
		break;
		case 'n':
		case 'N':
		case '0':
		disable_tp_pid();
		break;
		}

		return count;
		}

		static const struct file_operations fops_perftp = {
		.read = read_enabled_perftp_file_bool,
		.write = write_enabled_perftp_file_bool,
		.llseek = default_llseek,
		};

		int __init init_tracecounters(void)
		{
		struct dentry *dir;
		struct dentry *file;
		unsigned int value = 1;
		int cpu, rc;

		dir = debugfs_create_dir("perf_debug_tp", NULL);
		if (IS_ERR(dir))
		return PTR_ERR(dir);

		file = debugfs_create_file("enabled", 0660, dir,
		&value, &fops_perftp);
		if (IS_ERR(file)) {
		debugfs_remove(dir);
		return PTR_ERR(file);
		}

		for_each_possible_cpu(cpu) {
		per_cpu(old_pid, cpu) = -1;
		}
		rc = cpuhp_setup_state_nocalls(USE_CPUHP_STATE,
		"tracectr_cpu_hotplug",
		tracectr_cpu_hotplug_coming_up,
		NULL);
		WARN_ON(rc < 0);
		return 0;
		}

		int __exit exit_tracecounters(void)
		{
		cpuhp_remove_state_nocalls(USE_CPUHP_STATE);
		return 0;
		}

		late_initcall(init_tracecounters);

arch/arm/kernel/perf_trace_counters.h

0 → 100644

+106 −0

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0-only */
		/*
		* Copyright (c) 2021, Qualcomm Innovation Center, Inc. All rights reserved.
		*/

		#undef TRACE_SYSTEM
		#define TRACE_SYSTEM perf_trace_counters

		#if !defined(_PERF_TRACE_COUNTERS_H_) \|\| defined(TRACE_HEADER_MULTI_READ)
		#define _PERF_TRACE_COUNTERS_H_

		/* Ctr index for PMCNTENSET/CLR */
		#define CC 0x80000000
		#define C0 0x1
		#define C1 0x2
		#define C2 0x4
		#define C3 0x8
		#define C4 0x10
		#define C5 0x20
		#define C_ALL (CC \| C0 \| C1 \| C2 \| C3 \| C4 \| C5)
		#define NUM_L1_CTRS 6

		#include <linux/sched.h>
		#include <linux/cpumask.h>
		#include <linux/tracepoint.h>

		DECLARE_PER_CPU(u32, cntenset_val);
		DECLARE_PER_CPU(u32, previous_ccnt);
		DECLARE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);
		TRACE_EVENT(sched_switch_with_ctrs,

		TP_PROTO(pid_t prev, pid_t next),

		TP_ARGS(prev, next),

		TP_STRUCT__entry(
		__field(pid_t, old_pid)
		__field(pid_t, new_pid)
		__field(u32, cctr)
		__field(u32, ctr0)
		__field(u32, ctr1)
		__field(u32, ctr2)
		__field(u32, ctr3)
		__field(u32, ctr4)
		__field(u32, ctr5)
		),

		TP_fast_assign(
		u32 cpu = smp_processor_id();
		u32 i = 0;
		u32 cnten_val = 0;
		u32 total_ccnt = 0;
		u32 total_cnt = 0;
		u32 delta_l1_cnts[NUM_L1_CTRS];

		__entry->old_pid = prev;
		__entry->new_pid = next;

		cnten_val = per_cpu(cntenset_val, cpu);
		if (cnten_val & CC) {
		/* Read value */
		asm volatile("mrc p15, 0, %0, c9, c13, 0" : "=r" (total_ccnt));
		isb();
		__entry->cctr = total_ccnt - per_cpu(previous_ccnt, cpu);
		per_cpu(previous_ccnt, cpu) = total_ccnt;
		}

		for (i = 0; i < NUM_L1_CTRS; i++) {
		if (cnten_val & (1 << i)) {
		/* Select */
		asm volatile("mcr p15, 0, %0, c9, c12, 5" : : "r" (i));
		isb();
		/* Read value */
		asm volatile("mrc p15, 0, %0, c9, c13, 2" : "=r"
		(total_cnt));
		isb();
		delta_l1_cnts[i] = total_cnt -
		per_cpu(previous_l1_cnts[i], cpu);

		per_cpu(previous_l1_cnts[i], cpu) = total_cnt;
		} else
		delta_l1_cnts[i] = 0;
		}

		__entry->ctr0 = delta_l1_cnts[0];
		__entry->ctr1 = delta_l1_cnts[1];
		__entry->ctr2 = delta_l1_cnts[2];
		__entry->ctr3 = delta_l1_cnts[3];
		__entry->ctr4 = delta_l1_cnts[4];
		__entry->ctr5 = delta_l1_cnts[5];
		),

		TP_printk("prev_pid=%d, next_pid=%d, CCNTR: %u, CTR0: %u, CTR1: %u, CTR2: %u, CTR3: %u, CTR4: %u, CTR5: %u",
		__entry->old_pid, __entry->new_pid,
		__entry->cctr,
		__entry->ctr0, __entry->ctr1,
		__entry->ctr2, __entry->ctr3,
		__entry->ctr4, __entry->ctr5)

		);

		#endif
		#undef TRACE_INCLUDE_PATH
		#define TRACE_INCLUDE_PATH ../../arch/arm/kernel
		#define TRACE_INCLUDE_FILE perf_trace_counters
		#include <trace/define_trace.h>