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 #define pr_fmt(fmt) "pstore: " fmt
23 #include <linux/atomic.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/init.h>
27 #include <linux/kmsg_dump.h>
28 #include <linux/console.h>
29 #include <linux/module.h>
30 #include <linux/pstore.h>
31 #include <linux/zlib.h>
32 #include <linux/string.h>
33 #include <linux/timer.h>
34 #include <linux/slab.h>
35 #include <linux/uaccess.h>
36 #include <linux/hardirq.h>
37 #include <linux/jiffies.h>
38 #include <linux/workqueue.h>
43 * We defer making "oops" entries appear in pstore - see
44 * whether the system is actually still running well enough
45 * to let someone see the entry
47 static int pstore_update_ms = -1;
48 module_param_named(update_ms, pstore_update_ms, int, 0600);
49 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
50 "(default is -1, which means runtime updates are disabled; "
51 "enabling this option is not safe, it may lead to further "
52 "corruption on Oopses)");
54 static int pstore_new_entry;
56 static void pstore_timefunc(unsigned long);
57 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
59 static void pstore_dowork(struct work_struct *);
60 static DECLARE_WORK(pstore_work, pstore_dowork);
63 * pstore_lock just protects "psinfo" during
64 * calls to pstore_register()
66 static DEFINE_SPINLOCK(pstore_lock);
67 struct pstore_info *psinfo;
71 /* Compression parameters */
73 #define WINDOW_BITS 12
75 static struct z_stream_s stream;
77 static char *big_oops_buf;
78 static size_t big_oops_buf_sz;
80 /* How much of the console log to snapshot */
81 static unsigned long kmsg_bytes = 10240;
83 void pstore_set_kmsg_bytes(int bytes)
88 /* Tag each group of saved records with a sequence number */
91 static const char *get_reason_str(enum kmsg_dump_reason reason)
100 case KMSG_DUMP_RESTART:
104 case KMSG_DUMP_POWEROFF:
111 bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
114 * In case of NMI path, pstore shouldn't be blocked
115 * regardless of reason.
121 /* In panic case, other cpus are stopped by smp_send_stop(). */
122 case KMSG_DUMP_PANIC:
123 /* Emergency restart shouldn't be blocked by spin lock. */
124 case KMSG_DUMP_EMERG:
130 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
132 /* Derived from logfs_compress() */
133 static int pstore_compress(const void *in, void *out, size_t inlen,
139 err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
140 MEM_LEVEL, Z_DEFAULT_STRATEGY);
145 stream.avail_in = inlen;
147 stream.next_out = out;
148 stream.avail_out = outlen;
149 stream.total_out = 0;
151 err = zlib_deflate(&stream, Z_FINISH);
152 if (err != Z_STREAM_END)
155 err = zlib_deflateEnd(&stream);
159 if (stream.total_out >= stream.total_in)
162 ret = stream.total_out;
167 /* Derived from logfs_uncompress */
168 static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
173 err = zlib_inflateInit2(&stream, WINDOW_BITS);
178 stream.avail_in = inlen;
180 stream.next_out = out;
181 stream.avail_out = outlen;
182 stream.total_out = 0;
184 err = zlib_inflate(&stream, Z_FINISH);
185 if (err != Z_STREAM_END)
188 err = zlib_inflateEnd(&stream);
192 ret = stream.total_out;
197 static void allocate_buf_for_compression(void)
202 switch (psinfo->bufsize) {
203 /* buffer range for efivars */
213 /* buffer range for nvram, erst */
222 big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
223 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
225 size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
226 zlib_inflate_workspacesize());
227 stream.workspace = kmalloc(size, GFP_KERNEL);
228 if (!stream.workspace) {
229 pr_err("No memory for compression workspace; skipping compression\n");
234 pr_err("No memory for uncompressed data; skipping compression\n");
235 stream.workspace = NULL;
240 static void free_buf_for_compression(void)
242 kfree(stream.workspace);
243 stream.workspace = NULL;
249 * Called when compression fails, since the printk buffer
250 * would be fetched for compression calling it again when
251 * compression fails would have moved the iterator of
252 * printk buffer which results in fetching old contents.
253 * Copy the recent messages from big_oops_buf to psinfo->buf
255 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
260 total_len = hsize + len;
262 if (total_len > psinfo->bufsize) {
263 diff = total_len - psinfo->bufsize + hsize;
264 memcpy(psinfo->buf, big_oops_buf, hsize);
265 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
266 psinfo->bufsize - hsize);
267 total_len = psinfo->bufsize;
269 memcpy(psinfo->buf, big_oops_buf, total_len);
275 * callback from kmsg_dump. (s2,l2) has the most recently
276 * written bytes, older bytes are in (s1,l1). Save as much
277 * as we can from the end of the buffer.
279 static void pstore_dump(struct kmsg_dumper *dumper,
280 enum kmsg_dump_reason reason)
282 unsigned long total = 0;
285 unsigned int part = 1;
286 unsigned long flags = 0;
290 why = get_reason_str(reason);
292 if (pstore_cannot_block_path(reason)) {
293 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
295 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
296 , in_nmi() ? "NMI" : why);
299 spin_lock_irqsave(&psinfo->buf_lock, flags);
303 while (total < kmsg_bytes) {
312 if (big_oops_buf && is_locked) {
314 hsize = sprintf(dst, "%s#%d Part%u\n", why,
316 size = big_oops_buf_sz - hsize;
318 if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
322 zipped_len = pstore_compress(dst, psinfo->buf,
323 hsize + len, psinfo->bufsize);
325 if (zipped_len > 0) {
327 total_len = zipped_len;
330 total_len = copy_kmsg_to_buffer(hsize, len);
334 hsize = sprintf(dst, "%s#%d Part%u\n", why, oopscount,
336 size = psinfo->bufsize - hsize;
339 if (!kmsg_dump_get_buffer(dumper, true, dst,
344 total_len = hsize + len;
347 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
348 oopscount, compressed, total_len, psinfo);
349 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
350 pstore_new_entry = 1;
356 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
359 static struct kmsg_dumper pstore_dumper = {
364 * Register with kmsg_dump to save last part of console log on panic.
366 static void pstore_register_kmsg(void)
368 kmsg_dump_register(&pstore_dumper);
371 static void pstore_unregister_kmsg(void)
373 kmsg_dump_unregister(&pstore_dumper);
376 #ifdef CONFIG_PSTORE_CONSOLE
377 static void pstore_console_write(struct console *con, const char *s, unsigned c)
379 const char *e = s + c;
385 if (c > psinfo->bufsize)
388 if (oops_in_progress) {
389 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
392 spin_lock_irqsave(&psinfo->buf_lock, flags);
394 memcpy(psinfo->buf, s, c);
395 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
396 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
402 static struct console pstore_console = {
404 .write = pstore_console_write,
405 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
409 static void pstore_register_console(void)
411 register_console(&pstore_console);
414 static void pstore_unregister_console(void)
416 unregister_console(&pstore_console);
419 static void pstore_register_console(void) {}
420 static void pstore_unregister_console(void) {}
423 static int pstore_write_compat(enum pstore_type_id type,
424 enum kmsg_dump_reason reason,
425 u64 *id, unsigned int part, int count,
426 bool compressed, size_t size,
427 struct pstore_info *psi)
429 return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
434 * platform specific persistent storage driver registers with
435 * us here. If pstore is already mounted, call the platform
436 * read function right away to populate the file system. If not
437 * then the pstore mount code will call us later to fill out
440 int pstore_register(struct pstore_info *psi)
442 struct module *owner = psi->owner;
444 if (backend && strcmp(backend, psi->name))
447 spin_lock(&pstore_lock);
449 spin_unlock(&pstore_lock);
454 psi->write = pstore_write_compat;
456 mutex_init(&psinfo->read_mutex);
457 spin_unlock(&pstore_lock);
459 if (owner && !try_module_get(owner)) {
464 allocate_buf_for_compression();
466 if (pstore_is_mounted())
467 pstore_get_records(0);
469 pstore_register_kmsg();
471 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
472 pstore_register_console();
473 pstore_register_ftrace();
474 pstore_register_pmsg();
477 if (pstore_update_ms >= 0) {
478 pstore_timer.expires = jiffies +
479 msecs_to_jiffies(pstore_update_ms);
480 add_timer(&pstore_timer);
484 * Update the module parameter backend, so it is visible
485 * through /sys/module/pstore/parameters/backend
491 pr_info("Registered %s as persistent store backend\n", psi->name);
495 EXPORT_SYMBOL_GPL(pstore_register);
497 void pstore_unregister(struct pstore_info *psi)
499 if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
500 pstore_unregister_pmsg();
501 pstore_unregister_ftrace();
502 pstore_unregister_console();
504 pstore_unregister_kmsg();
506 free_buf_for_compression();
511 EXPORT_SYMBOL_GPL(pstore_unregister);
514 * Read all the records from the persistent store. Create
515 * files in our filesystem. Don't warn about -EEXIST errors
516 * when we are re-scanning the backing store looking to add new
519 void pstore_get_records(int quiet)
521 struct pstore_info *psi = psinfo;
526 enum pstore_type_id type;
527 struct timespec time;
530 int unzipped_len = -1;
535 mutex_lock(&psi->read_mutex);
536 if (psi->open && psi->open(psi))
539 while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
541 if (compressed && (type == PSTORE_TYPE_DMESG)) {
543 unzipped_len = pstore_decompress(buf,
547 if (unzipped_len > 0) {
553 pr_err("decompression failed;returned %d\n",
558 rc = pstore_mkfile(type, psi->name, id, count, buf,
559 compressed, (size_t)size, time, psi);
560 if (unzipped_len < 0) {
561 /* Free buffer other than big oops */
566 if (rc && (rc != -EEXIST || !quiet))
572 mutex_unlock(&psi->read_mutex);
575 pr_warn("failed to load %d record(s) from '%s'\n",
579 static void pstore_dowork(struct work_struct *work)
581 pstore_get_records(1);
584 static void pstore_timefunc(unsigned long dummy)
586 if (pstore_new_entry) {
587 pstore_new_entry = 0;
588 schedule_work(&pstore_work);
591 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
594 module_param(backend, charp, 0444);
595 MODULE_PARM_DESC(backend, "Pstore backend to use");