blob: 9ec22d3b4293f3c2d2c994927fd7102e4a20baec [file] [log] [blame]
Tony Luckca01d6d2010-12-28 14:25:21 -08001/*
2 * Persistent Storage - platform driver interface parts.
3 *
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/atomic.h>
21#include <linux/types.h>
22#include <linux/errno.h>
23#include <linux/init.h>
24#include <linux/kmsg_dump.h>
25#include <linux/module.h>
26#include <linux/pstore.h>
27#include <linux/string.h>
Luck, Tony6dda9262011-08-11 15:14:39 -070028#include <linux/timer.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080029#include <linux/slab.h>
30#include <linux/uaccess.h>
Don Zickusabd4d552011-08-12 10:54:51 -070031#include <linux/hardirq.h>
Luck, Tony6dda9262011-08-11 15:14:39 -070032#include <linux/workqueue.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080033
34#include "internal.h"
35
36/*
Luck, Tony6dda9262011-08-11 15:14:39 -070037 * We defer making "oops" entries appear in pstore - see
38 * whether the system is actually still running well enough
39 * to let someone see the entry
40 */
41#define PSTORE_INTERVAL (60 * HZ)
42
43static int pstore_new_entry;
44
45static void pstore_timefunc(unsigned long);
46static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
47
48static void pstore_dowork(struct work_struct *);
49static DECLARE_WORK(pstore_work, pstore_dowork);
50
51/*
Tony Luckca01d6d2010-12-28 14:25:21 -080052 * pstore_lock just protects "psinfo" during
53 * calls to pstore_register()
54 */
55static DEFINE_SPINLOCK(pstore_lock);
56static struct pstore_info *psinfo;
57
Matthew Garrettdee28e72011-07-21 16:57:55 -040058static char *backend;
59
Luck, Tony366f7e72011-03-18 15:33:43 -070060/* How much of the console log to snapshot */
Tony Luckca01d6d2010-12-28 14:25:21 -080061static unsigned long kmsg_bytes = 10240;
62
Luck, Tony366f7e72011-03-18 15:33:43 -070063void pstore_set_kmsg_bytes(int bytes)
Tony Luckca01d6d2010-12-28 14:25:21 -080064{
Luck, Tony366f7e72011-03-18 15:33:43 -070065 kmsg_bytes = bytes;
Tony Luckca01d6d2010-12-28 14:25:21 -080066}
67
Tony Luckca01d6d2010-12-28 14:25:21 -080068/* Tag each group of saved records with a sequence number */
69static int oopscount;
70
Tony Luck9f6af272011-03-22 16:01:49 -070071static char *reason_str[] = {
72 "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
73};
74
Tony Luckca01d6d2010-12-28 14:25:21 -080075/*
76 * callback from kmsg_dump. (s2,l2) has the most recently
77 * written bytes, older bytes are in (s1,l1). Save as much
78 * as we can from the end of the buffer.
79 */
80static void pstore_dump(struct kmsg_dumper *dumper,
81 enum kmsg_dump_reason reason,
82 const char *s1, unsigned long l1,
83 const char *s2, unsigned long l2)
84{
85 unsigned long s1_start, s2_start;
86 unsigned long l1_cpy, l2_cpy;
87 unsigned long size, total = 0;
Tony Luck9f6af272011-03-22 16:01:49 -070088 char *dst, *why;
Tony Luckca01d6d2010-12-28 14:25:21 -080089 u64 id;
Chen Gongb238b8f2011-10-12 09:17:24 -070090 int hsize, ret;
Matthew Garrettb94fdd02011-07-21 16:57:54 -040091 unsigned int part = 1;
Don Zickusabd4d552011-08-12 10:54:51 -070092 unsigned long flags = 0;
93 int is_locked = 0;
Tony Luckca01d6d2010-12-28 14:25:21 -080094
Tony Luck9f6af272011-03-22 16:01:49 -070095 if (reason < ARRAY_SIZE(reason_str))
96 why = reason_str[reason];
97 else
98 why = "Unknown";
99
Don Zickusabd4d552011-08-12 10:54:51 -0700100 if (in_nmi()) {
101 is_locked = spin_trylock(&psinfo->buf_lock);
102 if (!is_locked)
103 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
104 } else
105 spin_lock_irqsave(&psinfo->buf_lock, flags);
Tony Luckca01d6d2010-12-28 14:25:21 -0800106 oopscount++;
107 while (total < kmsg_bytes) {
108 dst = psinfo->buf;
Matthew Garrett56280682011-07-21 16:57:53 -0400109 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
Tony Luckca01d6d2010-12-28 14:25:21 -0800110 size = psinfo->bufsize - hsize;
111 dst += hsize;
112
113 l2_cpy = min(l2, size);
114 l1_cpy = min(l1, size - l2_cpy);
115
116 if (l1_cpy + l2_cpy == 0)
117 break;
118
119 s2_start = l2 - l2_cpy;
120 s1_start = l1 - l1_cpy;
121
122 memcpy(dst, s1 + s1_start, l1_cpy);
123 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
124
Kees Cook3d6d8d22011-11-17 13:13:29 -0800125 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
Matthew Garrett56280682011-07-21 16:57:53 -0400126 hsize + l1_cpy + l2_cpy, psinfo);
Chen Gongb238b8f2011-10-12 09:17:24 -0700127 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
Luck, Tony6dda9262011-08-11 15:14:39 -0700128 pstore_new_entry = 1;
Tony Luckca01d6d2010-12-28 14:25:21 -0800129 l1 -= l1_cpy;
130 l2 -= l2_cpy;
131 total += l1_cpy + l2_cpy;
Matthew Garrett56280682011-07-21 16:57:53 -0400132 part++;
Tony Luckca01d6d2010-12-28 14:25:21 -0800133 }
Don Zickusabd4d552011-08-12 10:54:51 -0700134 if (in_nmi()) {
135 if (is_locked)
136 spin_unlock(&psinfo->buf_lock);
137 } else
138 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
Tony Luckca01d6d2010-12-28 14:25:21 -0800139}
140
141static struct kmsg_dumper pstore_dumper = {
142 .dump = pstore_dump,
143};
144
145/*
146 * platform specific persistent storage driver registers with
147 * us here. If pstore is already mounted, call the platform
148 * read function right away to populate the file system. If not
149 * then the pstore mount code will call us later to fill out
150 * the file system.
151 *
152 * Register with kmsg_dump to save last part of console log on panic.
153 */
154int pstore_register(struct pstore_info *psi)
155{
156 struct module *owner = psi->owner;
157
158 spin_lock(&pstore_lock);
159 if (psinfo) {
160 spin_unlock(&pstore_lock);
161 return -EBUSY;
162 }
Matthew Garrettdee28e72011-07-21 16:57:55 -0400163
164 if (backend && strcmp(backend, psi->name)) {
165 spin_unlock(&pstore_lock);
166 return -EINVAL;
167 }
168
Tony Luckca01d6d2010-12-28 14:25:21 -0800169 psinfo = psi;
Kees Cookf6f82852011-11-17 12:58:07 -0800170 mutex_init(&psinfo->read_mutex);
Tony Luckca01d6d2010-12-28 14:25:21 -0800171 spin_unlock(&pstore_lock);
172
173 if (owner && !try_module_get(owner)) {
174 psinfo = NULL;
175 return -EINVAL;
176 }
177
178 if (pstore_is_mounted())
Luck, Tony6dda9262011-08-11 15:14:39 -0700179 pstore_get_records(0);
Tony Luckca01d6d2010-12-28 14:25:21 -0800180
181 kmsg_dump_register(&pstore_dumper);
182
Luck, Tony6dda9262011-08-11 15:14:39 -0700183 pstore_timer.expires = jiffies + PSTORE_INTERVAL;
184 add_timer(&pstore_timer);
185
Tony Luckca01d6d2010-12-28 14:25:21 -0800186 return 0;
187}
188EXPORT_SYMBOL_GPL(pstore_register);
189
190/*
Luck, Tony6dda9262011-08-11 15:14:39 -0700191 * Read all the records from the persistent store. Create
192 * files in our filesystem. Don't warn about -EEXIST errors
193 * when we are re-scanning the backing store looking to add new
194 * error records.
Tony Luckca01d6d2010-12-28 14:25:21 -0800195 */
Luck, Tony6dda9262011-08-11 15:14:39 -0700196void pstore_get_records(int quiet)
Tony Luckca01d6d2010-12-28 14:25:21 -0800197{
198 struct pstore_info *psi = psinfo;
Kees Cookf6f82852011-11-17 12:58:07 -0800199 char *buf = NULL;
Chen Gong8d38d742011-05-16 10:58:57 -0700200 ssize_t size;
Tony Luckca01d6d2010-12-28 14:25:21 -0800201 u64 id;
202 enum pstore_type_id type;
203 struct timespec time;
Chen Gong06cf91b2011-05-16 11:00:27 -0700204 int failed = 0, rc;
Tony Luckca01d6d2010-12-28 14:25:21 -0800205
206 if (!psi)
207 return;
208
Kees Cookf6f82852011-11-17 12:58:07 -0800209 mutex_lock(&psi->read_mutex);
Kees Cook2174f6d2011-11-18 13:49:00 -0800210 if (psi->open && psi->open(psi))
Chen Gong06cf91b2011-05-16 11:00:27 -0700211 goto out;
212
Kees Cookf6f82852011-11-17 12:58:07 -0800213 while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
214 rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
Luck, Tony6dda9262011-08-11 15:14:39 -0700215 time, psi);
Kees Cookf6f82852011-11-17 12:58:07 -0800216 kfree(buf);
217 buf = NULL;
Luck, Tony6dda9262011-08-11 15:14:39 -0700218 if (rc && (rc != -EEXIST || !quiet))
Tony Luckca01d6d2010-12-28 14:25:21 -0800219 failed++;
220 }
Kees Cook2174f6d2011-11-18 13:49:00 -0800221 if (psi->close)
222 psi->close(psi);
Chen Gong06cf91b2011-05-16 11:00:27 -0700223out:
Kees Cookf6f82852011-11-17 12:58:07 -0800224 mutex_unlock(&psi->read_mutex);
Tony Luckca01d6d2010-12-28 14:25:21 -0800225
226 if (failed)
227 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
228 failed, psi->name);
229}
230
Luck, Tony6dda9262011-08-11 15:14:39 -0700231static void pstore_dowork(struct work_struct *work)
232{
233 pstore_get_records(1);
234}
235
236static void pstore_timefunc(unsigned long dummy)
237{
238 if (pstore_new_entry) {
239 pstore_new_entry = 0;
240 schedule_work(&pstore_work);
241 }
242
243 mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL);
244}
245
Matthew Garrettdee28e72011-07-21 16:57:55 -0400246module_param(backend, charp, 0444);
247MODULE_PARM_DESC(backend, "Pstore backend to use");