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/* Copyright (c) 2016, 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.
*/
#define pr_fmt(fmt) "msm_evtlog:[%s] " fmt, __func__
#include "msm_evtlog.h"
#include <linux/slab.h>
#include <linux/sched.h>
#include <asm-generic/current.h>
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#define SIZE_MASK(x) (x - 1)
static int msm_evtlog_debugfs_dump(struct seq_file *s, void *data)
{
struct msm_evtlog *log = s->private;
unsigned long cnt; /* # of samples since clear */
unsigned long n; /* # of samples to print, also head index */
unsigned long i;
struct timespec timespec;
/**
* Prints in chronological order, oldest -> newest
* Note due to lock-less design, the first few printed entries
* may be corrupted by new writer not oldest.
* This is a tradeoff for speed of sampling
*/
cnt = atomic_read(&log->cnt);
if (!cnt)
return 0;
n = cnt & SIZE_MASK(log->size);
/**
* If not full, print from first log
* (which is index 1 since atomic_inc_return is prefix operator)
*/
i = (cnt < log->size) ? 0 : n;
seq_puts(s, "time_ns, pid, func, line, val1, val2, msg\n");
do {
i = (i + 1) & SIZE_MASK(log->size);
timespec = ktime_to_timespec(log->events[i].ktime);
seq_printf(s, "[%5lu.%06lu], %d, %s, %d, %llu, %llu, %s\n",
timespec.tv_sec,
timespec.tv_nsec / 1000,
log->events[i].pid,
log->events[i].func,
log->events[i].line,
log->events[i].val1,
log->events[i].val2,
log->events[i].msg);
} while (i != n);
return 0;
}
static int msm_evtlog_debugfs_open_dump(struct inode *inode, struct file *file)
{
return single_open(file, msm_evtlog_debugfs_dump, inode->i_private);
}
static ssize_t msm_evtlog_debugfs_write(
struct file *file,
const char __user *user_buf,
size_t size,
loff_t *ppos)
{
struct seq_file *s = file->private_data;
struct msm_evtlog *log = s->private;
char buf[64];
int buf_size;
buf_size = min(size, (sizeof(buf) - 1));
if (strncpy_from_user(buf, user_buf, buf_size) < 0)
return -EFAULT;
buf[buf_size] = 0;
if (strcmp(buf, "0") == 0)
atomic_set(&log->cnt, 0);
return size;
}
static const struct file_operations msm_evtlog_fops = {
.open = msm_evtlog_debugfs_open_dump,
.read = seq_read,
.write = msm_evtlog_debugfs_write,
.llseek = seq_lseek,
.release = single_release,
};
int msm_evtlog_init(
struct msm_evtlog *log,
int size,
struct dentry *parent)
{
if (!log || size < 1) {
pr_err("Invalid params\n");
return -EINVAL;
}
memset(log, 0, sizeof(*log));
log->size = roundup_pow_of_two(size);
log->events = kcalloc(log->size, sizeof(struct msm_evtlog_evt),
GFP_KERNEL);
if (!log->events) {
pr_err("Insufficient memory\n");
return -ENOMEM;
}
atomic_set(&log->cnt, 0);
log->dentry = debugfs_create_file("evtlog", S_IRUGO | S_IWUSR, parent,
log, &msm_evtlog_fops);
if (IS_ERR_OR_NULL(log->dentry)) {
int rc = PTR_ERR(log->dentry);
pr_err("debugfs create file failed, rc=%d\n", rc);
kfree(log->events);
return rc;
}
return 0;
}
void msm_evtlog_destroy(struct msm_evtlog *log)
{
debugfs_remove(log->dentry);
/* Caller needs to make sure that log sampling has stopped */
kfree(log->events);
}
void msm_evtlog_sample(
struct msm_evtlog *log,
const char *func,
const char *msg,
uint64_t val1,
uint64_t val2,
uint32_t line)
{
unsigned long i;
/**
* Since array sized with pow of 2, roll to 0 when cnt overflows
* mod the value with the size to get current idx into array
*/
i = (unsigned long)(atomic_inc_return(&log->cnt)) &
SIZE_MASK(log->size);
log->events[i].ktime = ktime_get();
log->events[i].func = func;
log->events[i].msg = msg;
log->events[i].val1 = val1;
log->events[i].val2 = val2;
log->events[i].line = line;
log->events[i].pid = current->pid;
}
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