File: ftrace.c

package info (click to toggle)
linux 3.16.7-ckt2-1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 734,120 kB
  • ctags: 2,369,605
  • sloc: ansic: 12,212,866; asm: 277,256; perl: 53,999; xml: 47,771; makefile: 30,481; sh: 8,035; python: 6,583; cpp: 5,121; yacc: 4,254; lex: 2,215; awk: 741; pascal: 231; lisp: 218; sed: 30
file content (131 lines) | stat: -rw-r--r-- 3,086 bytes parent folder | download | duplicates (15)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * Copyright 2012  Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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 <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 <asm/barrier.h>
#include "internal.h"

static void notrace pstore_ftrace_call(unsigned long ip,
				       unsigned long parent_ip,
				       struct ftrace_ops *op,
				       struct pt_regs *regs)
{
	unsigned long flags;
	struct pstore_ftrace_record rec = {};

	if (unlikely(oops_in_progress))
		return;

	local_irq_save(flags);

	rec.ip = ip;
	rec.parent_ip = parent_ip;
	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
	psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
			  0, sizeof(rec), psinfo);

	local_irq_restore(flags);
}

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)
		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,
};

void pstore_register_ftrace(void)
{
	struct dentry *dir;
	struct dentry *file;

	if (!psinfo->write_buf)
		return;

	dir = debugfs_create_dir("pstore", NULL);
	if (!dir) {
		pr_err("%s: unable to create pstore directory\n", __func__);
		return;
	}

	file = debugfs_create_file("record_ftrace", 0600, dir, NULL,
				   &pstore_knob_fops);
	if (!file) {
		pr_err("%s: unable to create record_ftrace file\n", __func__);
		goto err_file;
	}

	return;
err_file:
	debugfs_remove(dir);
}