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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2012 Google, Inc.
*/
#include <linux/kernel.h>
#include <linux/compiler.h>
#include <linux/irqflags.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/ftrace.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/cache.h>
#include <linux/slab.h>
#include <asm/barrier.h>
#include "internal.h"
/* This doesn't need to be atomic: speed is chosen over correctness here. */
static u64 pstore_ftrace_stamp;
static void notrace pstore_ftrace_call(unsigned long ip,
unsigned long parent_ip,
struct ftrace_ops *op,
struct pt_regs *regs)
{
int bit;
unsigned long flags;
struct pstore_ftrace_record rec = {};
struct pstore_record record = {
.type = PSTORE_TYPE_FTRACE,
.buf = (char *)&rec,
.size = sizeof(rec),
.psi = psinfo,
};
if (unlikely(oops_in_progress))
return;
bit = ftrace_test_recursion_trylock();
if (bit < 0)
return;
local_irq_save(flags);
rec.ip = ip;
rec.parent_ip = parent_ip;
pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
psinfo->write(&record);
local_irq_restore(flags);
ftrace_test_recursion_unlock(bit);
}
static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
.func = pstore_ftrace_call,
};
static DEFINE_MUTEX(pstore_ftrace_lock);
static bool pstore_ftrace_enabled;
static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
size_t count, loff_t *ppos)
{
u8 on;
ssize_t ret;
ret = kstrtou8_from_user(buf, count, 2, &on);
if (ret)
return ret;
mutex_lock(&pstore_ftrace_lock);
if (!on ^ pstore_ftrace_enabled)
goto out;
if (on) {
ftrace_ops_set_global_filter(&pstore_ftrace_ops);
ret = register_ftrace_function(&pstore_ftrace_ops);
} else {
ret = unregister_ftrace_function(&pstore_ftrace_ops);
}
if (ret) {
pr_err("%s: unable to %sregister ftrace ops: %zd\n",
__func__, on ? "" : "un", ret);
goto err;
}
pstore_ftrace_enabled = on;
out:
ret = count;
err:
mutex_unlock(&pstore_ftrace_lock);
return ret;
}
static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
size_t count, loff_t *ppos)
{
char val[] = { '0' + pstore_ftrace_enabled, '\n' };
return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
}
static const struct file_operations pstore_knob_fops = {
.open = simple_open,
.read = pstore_ftrace_knob_read,
.write = pstore_ftrace_knob_write,
};
static struct dentry *pstore_ftrace_dir;
void pstore_register_ftrace(void)
{
if (!psinfo->write)
return;
pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
&pstore_knob_fops);
}
void pstore_unregister_ftrace(void)
{
mutex_lock(&pstore_ftrace_lock);
if (pstore_ftrace_enabled) {
unregister_ftrace_function(&pstore_ftrace_ops);
pstore_ftrace_enabled = false;
}
mutex_unlock(&pstore_ftrace_lock);
debugfs_remove_recursive(pstore_ftrace_dir);
}
ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
const char *src_log, size_t src_log_size)
{
size_t dest_size, src_size, total, dest_off, src_off;
size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
void *merged_buf;
struct pstore_ftrace_record *drec, *srec, *mrec;
size_t record_size = sizeof(struct pstore_ftrace_record);
dest_off = *dest_log_size % record_size;
dest_size = *dest_log_size - dest_off;
src_off = src_log_size % record_size;
src_size = src_log_size - src_off;
total = dest_size + src_size;
merged_buf = kmalloc(total, GFP_KERNEL);
if (!merged_buf)
return -ENOMEM;
drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
srec = (struct pstore_ftrace_record *)(src_log + src_off);
mrec = (struct pstore_ftrace_record *)(merged_buf);
while (dest_size > 0 && src_size > 0) {
if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
pstore_ftrace_read_timestamp(&srec[src_idx])) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
} else {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
}
while (dest_size > 0) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
}
while (src_size > 0) {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
kfree(*dest_log);
*dest_log = merged_buf;
*dest_log_size = total;
return 0;
}
EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);
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