2 * Persistent Storage - platform driver interface parts.
4 * Copyright (C) 2007-2008 Google, Inc.
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/atomic.h>
22 #include <linux/types.h>
23 #include <linux/errno.h>
24 #include <linux/init.h>
25 #include <linux/kmsg_dump.h>
26 #include <linux/console.h>
27 #include <linux/module.h>
28 #include <linux/pstore.h>
29 #include <linux/zlib.h>
30 #include <linux/string.h>
31 #include <linux/timer.h>
32 #include <linux/slab.h>
33 #include <linux/uaccess.h>
34 #include <linux/hardirq.h>
35 #include <linux/jiffies.h>
36 #include <linux/workqueue.h>
41 * We defer making "oops" entries appear in pstore - see
42 * whether the system is actually still running well enough
43 * to let someone see the entry
45 static int pstore_update_ms = -1;
46 module_param_named(update_ms, pstore_update_ms, int, 0600);
47 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
48 "(default is -1, which means runtime updates are disabled; "
49 "enabling this option is not safe, it may lead to further "
50 "corruption on Oopses)");
52 static int pstore_new_entry;
54 static void pstore_timefunc(unsigned long);
55 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
57 static void pstore_dowork(struct work_struct *);
58 static DECLARE_WORK(pstore_work, pstore_dowork);
61 * pstore_lock just protects "psinfo" during
62 * calls to pstore_register()
64 static DEFINE_SPINLOCK(pstore_lock);
65 struct pstore_info *psinfo;
69 /* Compression parameters */
71 #define WINDOW_BITS 12
73 static struct z_stream_s stream;
75 static char *big_oops_buf;
76 static size_t big_oops_buf_sz;
78 /* How much of the console log to snapshot */
79 static unsigned long kmsg_bytes = 10240;
81 void pstore_set_kmsg_bytes(int bytes)
86 /* Tag each group of saved records with a sequence number */
89 static const char *get_reason_str(enum kmsg_dump_reason reason)
98 case KMSG_DUMP_RESTART:
102 case KMSG_DUMP_POWEROFF:
109 bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
112 * In case of NMI path, pstore shouldn't be blocked
113 * regardless of reason.
119 /* In panic case, other cpus are stopped by smp_send_stop(). */
120 case KMSG_DUMP_PANIC:
121 /* Emergency restart shouldn't be blocked by spin lock. */
122 case KMSG_DUMP_EMERG:
128 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
130 /* Derived from logfs_compress() */
131 static int pstore_compress(const void *in, void *out, size_t inlen,
137 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
138 MEM_LEVEL, Z_DEFAULT_STRATEGY);
143 stream.avail_in = inlen;
145 stream.next_out = out;
146 stream.avail_out = outlen;
147 stream.total_out = 0;
149 err = zlib_deflate(&stream, Z_FINISH);
150 if (err != Z_STREAM_END)
153 err = zlib_deflateEnd(&stream);
157 if (stream.total_out >= stream.total_in)
160 ret = stream.total_out;
165 /* Derived from logfs_uncompress */
166 static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
171 err = zlib_inflateInit2(&stream, WINDOW_BITS);
176 stream.avail_in = inlen;
178 stream.next_out = out;
179 stream.avail_out = outlen;
180 stream.total_out = 0;
182 err = zlib_inflate(&stream, Z_FINISH);
183 if (err != Z_STREAM_END)
186 err = zlib_inflateEnd(&stream);
190 ret = stream.total_out;
195 static void allocate_buf_for_compression(void)
200 switch (psinfo->bufsize) {
201 /* buffer range for efivars */
211 /* buffer range for nvram, erst */
220 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
221 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
223 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
224 zlib_inflate_workspacesize());
225 stream.workspace = kmalloc(size, GFP_KERNEL);
226 if (!stream.workspace) {
227 pr_err("pstore: No memory for compression workspace; "
228 "skipping compression\n");
233 pr_err("No memory for uncompressed data; "
234 "skipping compression\n");
235 stream.workspace = NULL;
241 * Called when compression fails, since the printk buffer
242 * would be fetched for compression calling it again when
243 * compression fails would have moved the iterator of
244 * printk buffer which results in fetching old contents.
245 * Copy the recent messages from big_oops_buf to psinfo->buf
247 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
252 total_len = hsize + len;
254 if (total_len > psinfo->bufsize) {
255 diff = total_len - psinfo->bufsize + hsize;
256 memcpy(psinfo->buf, big_oops_buf, hsize);
257 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
258 psinfo->bufsize - hsize);
259 total_len = psinfo->bufsize;
261 memcpy(psinfo->buf, big_oops_buf, total_len);
267 * callback from kmsg_dump. (s2,l2) has the most recently
268 * written bytes, older bytes are in (s1,l1). Save as much
269 * as we can from the end of the buffer.
271 static void pstore_dump(struct kmsg_dumper *dumper,
272 enum kmsg_dump_reason reason)
274 unsigned long total = 0;
277 unsigned int part = 1;
278 unsigned long flags = 0;
282 why = get_reason_str(reason);
284 if (pstore_cannot_block_path(reason)) {
285 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
287 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
288 , in_nmi() ? "NMI" : why);
291 spin_lock_irqsave(&psinfo->buf_lock, flags);
293 while (total < kmsg_bytes) {
304 hsize = sprintf(dst, "%s#%d Part%d\n", why,
306 size = big_oops_buf_sz - hsize;
308 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
312 zipped_len = pstore_compress(dst, psinfo->buf,
313 hsize + len, psinfo->bufsize);
315 if (zipped_len > 0) {
317 total_len = zipped_len;
319 pr_err("pstore: compression failed for Part %d"
320 " returned %d\n", part, zipped_len);
321 pr_err("pstore: Capture uncompressed"
322 " oops/panic report of Part %d\n", part);
324 total_len = copy_kmsg_to_buffer(hsize, len);
328 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount,
330 size = psinfo->bufsize - hsize;
333 if (!kmsg_dump_get_buffer(dumper, true, dst,
338 total_len = hsize + len;
341 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
342 oopscount, compressed, total_len, psinfo);
343 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
344 pstore_new_entry = 1;
349 if (pstore_cannot_block_path(reason)) {
351 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
353 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
356 static struct kmsg_dumper pstore_dumper = {
360 #ifdef CONFIG_PSTORE_CONSOLE
361 static void pstore_console_write(struct console *con, const char *s, unsigned c)
363 const char *e = s + c;
369 if (c > psinfo->bufsize)
372 if (oops_in_progress) {
373 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
376 spin_lock_irqsave(&psinfo->buf_lock, flags);
378 memcpy(psinfo->buf, s, c);
379 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
380 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
386 static struct console pstore_console = {
388 .write = pstore_console_write,
389 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
393 static void pstore_register_console(void)
395 register_console(&pstore_console);
398 static void pstore_register_console(void) {}
401 static int pstore_write_compat(enum pstore_type_id type,
402 enum kmsg_dump_reason reason,
403 u64 *id, unsigned int part, int count,
404 bool compressed, size_t size,
405 struct pstore_info *psi)
407 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
412 * platform specific persistent storage driver registers with
413 * us here. If pstore is already mounted, call the platform
414 * read function right away to populate the file system. If not
415 * then the pstore mount code will call us later to fill out
418 * Register with kmsg_dump to save last part of console log on panic.
420 int pstore_register(struct pstore_info *psi)
422 struct module *owner = psi->owner;
424 if (backend && strcmp(backend, psi->name))
427 spin_lock(&pstore_lock);
429 spin_unlock(&pstore_lock);
434 psi->write = pstore_write_compat;
436 mutex_init(&psinfo->read_mutex);
437 spin_unlock(&pstore_lock);
439 if (owner && !try_module_get(owner)) {
444 allocate_buf_for_compression();
446 if (pstore_is_mounted())
447 pstore_get_records(0);
449 kmsg_dump_register(&pstore_dumper);
450 pstore_register_console();
451 pstore_register_ftrace();
453 if (pstore_update_ms >= 0) {
454 pstore_timer.expires = jiffies +
455 msecs_to_jiffies(pstore_update_ms);
456 add_timer(&pstore_timer);
459 pr_info("pstore: Registered %s as persistent store backend\n",
464 EXPORT_SYMBOL_GPL(pstore_register);
467 * Read all the records from the persistent store. Create
468 * files in our filesystem. Don't warn about -EEXIST errors
469 * when we are re-scanning the backing store looking to add new
472 void pstore_get_records(int quiet)
474 struct pstore_info *psi = psinfo;
479 enum pstore_type_id type;
480 struct timespec time;
483 int unzipped_len = -1;
488 mutex_lock(&psi->read_mutex);
489 if (psi->open && psi->open(psi))
492 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
494 if (compressed && (type == PSTORE_TYPE_DMESG)) {
496 unzipped_len = pstore_decompress(buf,
500 if (unzipped_len > 0) {
505 pr_err("pstore: decompression failed;"
506 "returned %d\n", unzipped_len);
510 rc = pstore_mkfile(type, psi->name, id, count, buf,
511 compressed, (size_t)size, time, psi);
512 if (unzipped_len < 0) {
513 /* Free buffer other than big oops */
518 if (rc && (rc != -EEXIST || !quiet))
524 mutex_unlock(&psi->read_mutex);
527 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
531 static void pstore_dowork(struct work_struct *work)
533 pstore_get_records(1);
536 static void pstore_timefunc(unsigned long dummy)
538 if (pstore_new_entry) {
539 pstore_new_entry = 0;
540 schedule_work(&pstore_work);
543 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
546 module_param(backend, charp, 0444);
547 MODULE_PARM_DESC(backend, "Pstore backend to use");