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/* Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <asm/thread_notify.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <linux/cpu.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(unsigned long, l2_enmask);
DEFINE_PER_CPU(u32, previous_ccnt);
DEFINE_PER_CPU(u32[NUM_L1_CTRS], previous_l1_cnts);
DEFINE_PER_CPU(u32[NUM_L2_PERCPU], previous_l2_cnts);
DEFINE_PER_CPU(u32, old_pid);
DEFINE_PER_CPU(u32, hotplug_flag);
/* Reset per_cpu variables that store counter values uppn CPU hotplug */
static int tracectr_cpu_hotplug_notifier(struct notifier_block *self,
unsigned long action, void *hcpu)
{
int ret = NOTIFY_OK;
int cpu = (int)hcpu;
if ((action & (~CPU_TASKS_FROZEN)) == CPU_STARTING)
per_cpu(hotplug_flag, cpu) = 1;
return ret;
}
static struct notifier_block tracectr_cpu_hotplug_notifier_block = {
.notifier_call = tracectr_cpu_hotplug_notifier,
};
static void setup_prev_cnts(u32 cpu, u32 cnten_val)
{
int i;
if (cnten_val & CC) {
/* Read value */
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));
/* Read value */
asm volatile("mrc p15, 0, %0, c9, c13, 2"
: "=r"(per_cpu(previous_l1_cnts[i], cpu)));
}
}
}
static int tracectr_notifier(struct notifier_block *self, unsigned long cmd,
void *v)
{
u32 cnten_val;
u32 l2_cnten_val;
u32 val;
u32 bit;
int i;
int num_l2ctrs;
struct thread_info *thread = v;
int current_pid;
u32 cpu = thread->cpu;
unsigned long idx;
u32 num_cores = nr_cpu_ids;
if (cmd != THREAD_NOTIFY_SWITCH)
return -EFAULT;
current_pid = thread->task->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 {
/* check # L2 counters */
val = get_l2_indirect_reg(L2PMCR);
num_l2ctrs = ((val >> 11) & 0x1f) + 1;
l2_cnten_val = get_l2_indirect_reg(L2PMCNTENSET);
per_cpu(l2_enmask, cpu) = 0;
for (i = 0; i < NUM_L2_PERCPU; i++) {
/*
* Assign L2 counters to cores sequentially
* starting from zero. A core could have
* multiple L2 counters allocated if # L2
* counters is more than the # cores
*/
idx = cpu + (num_cores * i);
bit = BIT(idx);
if (idx < num_l2ctrs && (l2_cnten_val & bit)) {
/* Disable */
set_l2_indirect_reg(L2PMCNTENCLR, bit);
per_cpu(l2_enmask, cpu) |= bit;
}
}
trace_sched_switch_with_ctrs(per_cpu(old_pid, cpu),
current_pid);
/* Enable L2*/
set_l2_indirect_reg(L2PMCNTENSET,
per_cpu(l2_enmask, cpu));
}
/* Enable all the counters that were disabled */
asm volatile("mcr p15, 0, %0, c9, c12, 1" : : "r"(cnten_val));
}
per_cpu(old_pid, cpu) = current_pid;
return NOTIFY_OK;
}
static struct notifier_block tracectr_notifier_block = {
.notifier_call = tracectr_notifier,
};
static void enable_tp_pid(void)
{
if (tp_pid_state == 0) {
tp_pid_state = 1;
thread_register_notifier(&tracectr_notifier_block);
}
}
static void disable_tp_pid(void)
{
if (tp_pid_state == 1) {
tp_pid_state = 0;
thread_unregister_notifier(&tracectr_notifier_block);
}
}
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_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;
dir = debugfs_create_dir("perf_debug_tp", NULL);
if (!dir)
return -ENOMEM;
file = debugfs_create_file("enabled", 0660, dir,
&value, &fops_perftp);
if (!file) {
debugfs_remove(dir);
return -ENOMEM;
}
register_cpu_notifier(&tracectr_cpu_hotplug_notifier_block);
for_each_possible_cpu(cpu)
per_cpu(old_pid, cpu) = -1;
return 0;
}
int __exit exit_tracecounters(void)
{
unregister_cpu_notifier(&tracectr_cpu_hotplug_notifier_block);
return 0;
}
late_initcall(init_tracecounters);
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