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1/*
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>
28#include <linux/slab.h>
29#include <linux/uaccess.h>
30
31#include "internal.h"
32
33/*
34 * pstore_lock just protects "psinfo" during
35 * calls to pstore_register()
36 */
37static DEFINE_SPINLOCK(pstore_lock);
38static struct pstore_info *psinfo;
39
40static char *backend;
41
42/* How much of the console log to snapshot */
43static unsigned long kmsg_bytes = 10240;
44
45void pstore_set_kmsg_bytes(int bytes)
46{
47 kmsg_bytes = bytes;
48}
49
50/* Tag each group of saved records with a sequence number */
51static int oopscount;
52
53static char *reason_str[] = {
54 "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
55};
56
57/*
58 * callback from kmsg_dump. (s2,l2) has the most recently
59 * written bytes, older bytes are in (s1,l1). Save as much
60 * as we can from the end of the buffer.
61 */
62static void pstore_dump(struct kmsg_dumper *dumper,
63 enum kmsg_dump_reason reason,
64 const char *s1, unsigned long l1,
65 const char *s2, unsigned long l2)
66{
67 unsigned long s1_start, s2_start;
68 unsigned long l1_cpy, l2_cpy;
69 unsigned long size, total = 0;
70 char *dst, *why;
71 u64 id;
72 int hsize;
73 unsigned int part = 1;
74
75 if (reason < ARRAY_SIZE(reason_str))
76 why = reason_str[reason];
77 else
78 why = "Unknown";
79
80 mutex_lock(&psinfo->buf_mutex);
81 oopscount++;
82 while (total < kmsg_bytes) {
83 dst = psinfo->buf;
84 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
85 size = psinfo->bufsize - hsize;
86 dst += hsize;
87
88 l2_cpy = min(l2, size);
89 l1_cpy = min(l1, size - l2_cpy);
90
91 if (l1_cpy + l2_cpy == 0)
92 break;
93
94 s2_start = l2 - l2_cpy;
95 s1_start = l1 - l1_cpy;
96
97 memcpy(dst, s1 + s1_start, l1_cpy);
98 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
99
100 id = psinfo->write(PSTORE_TYPE_DMESG, part,
101 hsize + l1_cpy + l2_cpy, psinfo);
102 if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
103 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
104 psinfo->buf, hsize + l1_cpy + l2_cpy,
105 CURRENT_TIME, psinfo);
106 l1 -= l1_cpy;
107 l2 -= l2_cpy;
108 total += l1_cpy + l2_cpy;
109 part++;
110 }
111 mutex_unlock(&psinfo->buf_mutex);
112}
113
114static struct kmsg_dumper pstore_dumper = {
115 .dump = pstore_dump,
116};
117
118/*
119 * platform specific persistent storage driver registers with
120 * us here. If pstore is already mounted, call the platform
121 * read function right away to populate the file system. If not
122 * then the pstore mount code will call us later to fill out
123 * the file system.
124 *
125 * Register with kmsg_dump to save last part of console log on panic.
126 */
127int pstore_register(struct pstore_info *psi)
128{
129 struct module *owner = psi->owner;
130
131 spin_lock(&pstore_lock);
132 if (psinfo) {
133 spin_unlock(&pstore_lock);
134 return -EBUSY;
135 }
136
137 if (backend && strcmp(backend, psi->name)) {
138 spin_unlock(&pstore_lock);
139 return -EINVAL;
140 }
141
142 psinfo = psi;
143 spin_unlock(&pstore_lock);
144
145 if (owner && !try_module_get(owner)) {
146 psinfo = NULL;
147 return -EINVAL;
148 }
149
150 if (pstore_is_mounted())
151 pstore_get_records();
152
153 kmsg_dump_register(&pstore_dumper);
154
155 return 0;
156}
157EXPORT_SYMBOL_GPL(pstore_register);
158
159/*
160 * Read all the records from the persistent store. Create and
161 * file files in our filesystem.
162 */
163void pstore_get_records(void)
164{
165 struct pstore_info *psi = psinfo;
166 ssize_t size;
167 u64 id;
168 enum pstore_type_id type;
169 struct timespec time;
170 int failed = 0, rc;
171
172 if (!psi)
173 return;
174
175 mutex_lock(&psinfo->buf_mutex);
176 rc = psi->open(psi);
177 if (rc)
178 goto out;
179
180 while ((size = psi->read(&id, &type, &time, psi)) > 0) {
181 if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
182 time, psi))
183 failed++;
184 }
185 psi->close(psi);
186out:
187 mutex_unlock(&psinfo->buf_mutex);
188
189 if (failed)
190 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
191 failed, psi->name);
192}
193
194/*
195 * Call platform driver to write a record to the
196 * persistent store.
197 */
198int pstore_write(enum pstore_type_id type, char *buf, size_t size)
199{
200 u64 id;
201
202 if (!psinfo)
203 return -ENODEV;
204
205 if (size > psinfo->bufsize)
206 return -EFBIG;
207
208 mutex_lock(&psinfo->buf_mutex);
209 memcpy(psinfo->buf, buf, size);
210 id = psinfo->write(type, 0, size, psinfo);
211 if (pstore_is_mounted())
212 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
213 size, CURRENT_TIME, psinfo);
214 mutex_unlock(&psinfo->buf_mutex);
215
216 return 0;
217}
218EXPORT_SYMBOL_GPL(pstore_write);
219
220module_param(backend, charp, 0444);
221MODULE_PARM_DESC(backend, "Pstore backend to use");
1/*
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>
28#include <linux/timer.h>
29#include <linux/slab.h>
30#include <linux/uaccess.h>
31#include <linux/hardirq.h>
32#include <linux/workqueue.h>
33
34#include "internal.h"
35
36/*
37 * 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/*
52 * pstore_lock just protects "psinfo" during
53 * calls to pstore_register()
54 */
55static DEFINE_SPINLOCK(pstore_lock);
56static struct pstore_info *psinfo;
57
58static char *backend;
59
60/* How much of the console log to snapshot */
61static unsigned long kmsg_bytes = 10240;
62
63void pstore_set_kmsg_bytes(int bytes)
64{
65 kmsg_bytes = bytes;
66}
67
68/* Tag each group of saved records with a sequence number */
69static int oopscount;
70
71static const char *get_reason_str(enum kmsg_dump_reason reason)
72{
73 switch (reason) {
74 case KMSG_DUMP_PANIC:
75 return "Panic";
76 case KMSG_DUMP_OOPS:
77 return "Oops";
78 case KMSG_DUMP_EMERG:
79 return "Emergency";
80 case KMSG_DUMP_RESTART:
81 return "Restart";
82 case KMSG_DUMP_HALT:
83 return "Halt";
84 case KMSG_DUMP_POWEROFF:
85 return "Poweroff";
86 default:
87 return "Unknown";
88 }
89}
90
91/*
92 * callback from kmsg_dump. (s2,l2) has the most recently
93 * written bytes, older bytes are in (s1,l1). Save as much
94 * as we can from the end of the buffer.
95 */
96static void pstore_dump(struct kmsg_dumper *dumper,
97 enum kmsg_dump_reason reason)
98{
99 unsigned long total = 0;
100 const char *why;
101 u64 id;
102 unsigned int part = 1;
103 unsigned long flags = 0;
104 int is_locked = 0;
105 int ret;
106
107 why = get_reason_str(reason);
108
109 if (in_nmi()) {
110 is_locked = spin_trylock(&psinfo->buf_lock);
111 if (!is_locked)
112 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
113 } else
114 spin_lock_irqsave(&psinfo->buf_lock, flags);
115 oopscount++;
116 while (total < kmsg_bytes) {
117 char *dst;
118 unsigned long size;
119 int hsize;
120 size_t len;
121
122 dst = psinfo->buf;
123 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
124 size = psinfo->bufsize - hsize;
125 dst += hsize;
126
127 if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
128 break;
129
130 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
131 hsize + len, psinfo);
132 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
133 pstore_new_entry = 1;
134
135 total += hsize + len;
136 part++;
137 }
138 if (in_nmi()) {
139 if (is_locked)
140 spin_unlock(&psinfo->buf_lock);
141 } else
142 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
143}
144
145static struct kmsg_dumper pstore_dumper = {
146 .dump = pstore_dump,
147};
148
149/*
150 * platform specific persistent storage driver registers with
151 * us here. If pstore is already mounted, call the platform
152 * read function right away to populate the file system. If not
153 * then the pstore mount code will call us later to fill out
154 * the file system.
155 *
156 * Register with kmsg_dump to save last part of console log on panic.
157 */
158int pstore_register(struct pstore_info *psi)
159{
160 struct module *owner = psi->owner;
161
162 spin_lock(&pstore_lock);
163 if (psinfo) {
164 spin_unlock(&pstore_lock);
165 return -EBUSY;
166 }
167
168 if (backend && strcmp(backend, psi->name)) {
169 spin_unlock(&pstore_lock);
170 return -EINVAL;
171 }
172
173 psinfo = psi;
174 mutex_init(&psinfo->read_mutex);
175 spin_unlock(&pstore_lock);
176
177 if (owner && !try_module_get(owner)) {
178 psinfo = NULL;
179 return -EINVAL;
180 }
181
182 if (pstore_is_mounted())
183 pstore_get_records(0);
184
185 kmsg_dump_register(&pstore_dumper);
186
187 pstore_timer.expires = jiffies + PSTORE_INTERVAL;
188 add_timer(&pstore_timer);
189
190 return 0;
191}
192EXPORT_SYMBOL_GPL(pstore_register);
193
194/*
195 * Read all the records from the persistent store. Create
196 * files in our filesystem. Don't warn about -EEXIST errors
197 * when we are re-scanning the backing store looking to add new
198 * error records.
199 */
200void pstore_get_records(int quiet)
201{
202 struct pstore_info *psi = psinfo;
203 char *buf = NULL;
204 ssize_t size;
205 u64 id;
206 enum pstore_type_id type;
207 struct timespec time;
208 int failed = 0, rc;
209
210 if (!psi)
211 return;
212
213 mutex_lock(&psi->read_mutex);
214 if (psi->open && psi->open(psi))
215 goto out;
216
217 while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
218 rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
219 time, psi);
220 kfree(buf);
221 buf = NULL;
222 if (rc && (rc != -EEXIST || !quiet))
223 failed++;
224 }
225 if (psi->close)
226 psi->close(psi);
227out:
228 mutex_unlock(&psi->read_mutex);
229
230 if (failed)
231 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
232 failed, psi->name);
233}
234
235static void pstore_dowork(struct work_struct *work)
236{
237 pstore_get_records(1);
238}
239
240static void pstore_timefunc(unsigned long dummy)
241{
242 if (pstore_new_entry) {
243 pstore_new_entry = 0;
244 schedule_work(&pstore_work);
245 }
246
247 mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL);
248}
249
250module_param(backend, charp, 0444);
251MODULE_PARM_DESC(backend, "Pstore backend to use");