blob: 43b12807a51d71ad39c41e55e8ac83473e5ac7a6 [file] [log] [blame]
Anton Vorontsov060287b2012-07-09 17:10:41 -07001/*
2 * Copyright 2012 Google, Inc.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14#include <linux/kernel.h>
15#include <linux/compiler.h>
16#include <linux/irqflags.h>
17#include <linux/percpu.h>
18#include <linux/smp.h>
19#include <linux/atomic.h>
Anton Vorontsov65f8c952012-07-17 14:26:15 -070020#include <linux/types.h>
21#include <linux/mutex.h>
22#include <linux/ftrace.h>
23#include <linux/fs.h>
24#include <linux/debugfs.h>
25#include <linux/err.h>
26#include <linux/cache.h>
Anton Vorontsov060287b2012-07-09 17:10:41 -070027#include <asm/barrier.h>
28#include "internal.h"
29
Anton Vorontsov65f8c952012-07-17 14:26:15 -070030static void notrace pstore_ftrace_call(unsigned long ip,
Anton Vorontsovebacfd12012-11-14 18:48:15 -080031 unsigned long parent_ip,
32 struct ftrace_ops *op,
33 struct pt_regs *regs)
Anton Vorontsov060287b2012-07-09 17:10:41 -070034{
Anton Vorontsov65f8c952012-07-17 14:26:15 -070035 unsigned long flags;
Anton Vorontsov060287b2012-07-09 17:10:41 -070036 struct pstore_ftrace_record rec = {};
37
38 if (unlikely(oops_in_progress))
39 return;
40
Anton Vorontsov65f8c952012-07-17 14:26:15 -070041 local_irq_save(flags);
42
Anton Vorontsov060287b2012-07-09 17:10:41 -070043 rec.ip = ip;
44 rec.parent_ip = parent_ip;
45 pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
46 psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
47 sizeof(rec), psinfo);
Anton Vorontsov65f8c952012-07-17 14:26:15 -070048
49 local_irq_restore(flags);
50}
51
52static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
53 .func = pstore_ftrace_call,
54};
55
56static DEFINE_MUTEX(pstore_ftrace_lock);
57static bool pstore_ftrace_enabled;
58
59static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
60 size_t count, loff_t *ppos)
61{
62 u8 on;
63 ssize_t ret;
64
65 ret = kstrtou8_from_user(buf, count, 2, &on);
66 if (ret)
67 return ret;
68
69 mutex_lock(&pstore_ftrace_lock);
70
71 if (!on ^ pstore_ftrace_enabled)
72 goto out;
73
74 if (on)
75 ret = register_ftrace_function(&pstore_ftrace_ops);
76 else
77 ret = unregister_ftrace_function(&pstore_ftrace_ops);
78 if (ret) {
79 pr_err("%s: unable to %sregister ftrace ops: %zd\n",
80 __func__, on ? "" : "un", ret);
81 goto err;
82 }
83
84 pstore_ftrace_enabled = on;
85out:
86 ret = count;
87err:
88 mutex_unlock(&pstore_ftrace_lock);
89
90 return ret;
91}
92
93static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
94 size_t count, loff_t *ppos)
95{
96 char val[] = { '0' + pstore_ftrace_enabled, '\n' };
97
98 return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
99}
100
101static const struct file_operations pstore_knob_fops = {
102 .open = simple_open,
103 .read = pstore_ftrace_knob_read,
104 .write = pstore_ftrace_knob_write,
105};
106
107void pstore_register_ftrace(void)
108{
109 struct dentry *dir;
110 struct dentry *file;
111
112 if (!psinfo->write_buf)
113 return;
114
115 dir = debugfs_create_dir("pstore", NULL);
116 if (!dir) {
117 pr_err("%s: unable to create pstore directory\n", __func__);
118 return;
119 }
120
121 file = debugfs_create_file("record_ftrace", 0600, dir, NULL,
122 &pstore_knob_fops);
123 if (!file) {
124 pr_err("%s: unable to create record_ftrace file\n", __func__);
125 goto err_file;
126 }
127
128 return;
129err_file:
130 debugfs_remove(dir);
Anton Vorontsov060287b2012-07-09 17:10:41 -0700131}