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![Luck, Tony](/assets/img/avatar_default.png)
Some pstore backing devices use on board flash as persistent storage. These have limited numbers of write cycles so it is a poor idea to use them from high frequency operations. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
546 lines
13 KiB
C
546 lines
13 KiB
C
/*
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* Persistent Storage - platform driver interface parts.
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*
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* Copyright (C) 2007-2008 Google, Inc.
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/atomic.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kmsg_dump.h>
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#include <linux/console.h>
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#include <linux/module.h>
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#include <linux/pstore.h>
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#include <linux/zlib.h>
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#include <linux/string.h>
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#include <linux/timer.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/jiffies.h>
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#include <linux/workqueue.h>
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#include "internal.h"
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/*
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* We defer making "oops" entries appear in pstore - see
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* whether the system is actually still running well enough
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* to let someone see the entry
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*/
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static int pstore_update_ms = -1;
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module_param_named(update_ms, pstore_update_ms, int, 0600);
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MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
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"(default is -1, which means runtime updates are disabled; "
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"enabling this option is not safe, it may lead to further "
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"corruption on Oopses)");
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static int pstore_new_entry;
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static void pstore_timefunc(unsigned long);
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static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
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static void pstore_dowork(struct work_struct *);
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static DECLARE_WORK(pstore_work, pstore_dowork);
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/*
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* pstore_lock just protects "psinfo" during
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* calls to pstore_register()
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*/
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static DEFINE_SPINLOCK(pstore_lock);
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struct pstore_info *psinfo;
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static char *backend;
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/* Compression parameters */
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#define COMPR_LEVEL 6
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#define WINDOW_BITS 12
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#define MEM_LEVEL 4
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static struct z_stream_s stream;
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static char *big_oops_buf;
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static size_t big_oops_buf_sz;
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/* How much of the console log to snapshot */
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static unsigned long kmsg_bytes = 10240;
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void pstore_set_kmsg_bytes(int bytes)
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{
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kmsg_bytes = bytes;
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}
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/* Tag each group of saved records with a sequence number */
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static int oopscount;
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static const char *get_reason_str(enum kmsg_dump_reason reason)
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{
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switch (reason) {
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case KMSG_DUMP_PANIC:
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return "Panic";
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case KMSG_DUMP_OOPS:
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return "Oops";
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case KMSG_DUMP_EMERG:
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return "Emergency";
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case KMSG_DUMP_RESTART:
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return "Restart";
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case KMSG_DUMP_HALT:
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return "Halt";
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case KMSG_DUMP_POWEROFF:
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return "Poweroff";
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default:
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return "Unknown";
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}
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}
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bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
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{
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/*
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* In case of NMI path, pstore shouldn't be blocked
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* regardless of reason.
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*/
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if (in_nmi())
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return true;
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switch (reason) {
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/* In panic case, other cpus are stopped by smp_send_stop(). */
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case KMSG_DUMP_PANIC:
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/* Emergency restart shouldn't be blocked by spin lock. */
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case KMSG_DUMP_EMERG:
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return true;
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default:
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return false;
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}
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}
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EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
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/* Derived from logfs_compress() */
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static int pstore_compress(const void *in, void *out, size_t inlen,
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size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
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MEM_LEVEL, Z_DEFAULT_STRATEGY);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_deflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_deflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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if (stream.total_out >= stream.total_in)
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goto error;
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ret = stream.total_out;
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error:
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return ret;
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}
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/* Derived from logfs_uncompress */
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static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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err = zlib_inflateInit2(&stream, WINDOW_BITS);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_inflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_inflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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ret = stream.total_out;
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error:
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return ret;
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}
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static void allocate_buf_for_compression(void)
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{
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size_t size;
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size_t cmpr;
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switch (psinfo->bufsize) {
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/* buffer range for efivars */
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case 1000 ... 2000:
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cmpr = 56;
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break;
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case 2001 ... 3000:
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cmpr = 54;
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break;
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case 3001 ... 3999:
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cmpr = 52;
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break;
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/* buffer range for nvram, erst */
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case 4000 ... 10000:
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cmpr = 45;
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break;
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default:
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cmpr = 60;
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break;
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}
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big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr;
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big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
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if (big_oops_buf) {
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size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
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zlib_inflate_workspacesize());
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stream.workspace = kmalloc(size, GFP_KERNEL);
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if (!stream.workspace) {
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pr_err("pstore: No memory for compression workspace; "
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"skipping compression\n");
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kfree(big_oops_buf);
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big_oops_buf = NULL;
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}
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} else {
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pr_err("No memory for uncompressed data; "
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"skipping compression\n");
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stream.workspace = NULL;
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}
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}
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/*
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* Called when compression fails, since the printk buffer
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* would be fetched for compression calling it again when
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* compression fails would have moved the iterator of
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* printk buffer which results in fetching old contents.
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* Copy the recent messages from big_oops_buf to psinfo->buf
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*/
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static size_t copy_kmsg_to_buffer(int hsize, size_t len)
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{
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size_t total_len;
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size_t diff;
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total_len = hsize + len;
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if (total_len > psinfo->bufsize) {
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diff = total_len - psinfo->bufsize + hsize;
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memcpy(psinfo->buf, big_oops_buf, hsize);
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memcpy(psinfo->buf + hsize, big_oops_buf + diff,
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psinfo->bufsize - hsize);
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total_len = psinfo->bufsize;
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} else
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memcpy(psinfo->buf, big_oops_buf, total_len);
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return total_len;
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}
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/*
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* callback from kmsg_dump. (s2,l2) has the most recently
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* written bytes, older bytes are in (s1,l1). Save as much
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* as we can from the end of the buffer.
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*/
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static void pstore_dump(struct kmsg_dumper *dumper,
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enum kmsg_dump_reason reason)
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{
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unsigned long total = 0;
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const char *why;
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u64 id;
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unsigned int part = 1;
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unsigned long flags = 0;
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int is_locked = 0;
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int ret;
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why = get_reason_str(reason);
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if (pstore_cannot_block_path(reason)) {
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is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
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if (!is_locked) {
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pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
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, in_nmi() ? "NMI" : why);
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}
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} else
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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oopscount++;
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while (total < kmsg_bytes) {
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char *dst;
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unsigned long size;
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int hsize;
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int zipped_len = -1;
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size_t len;
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bool compressed;
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size_t total_len;
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if (big_oops_buf) {
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dst = big_oops_buf;
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hsize = sprintf(dst, "%s#%d Part%d\n", why,
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oopscount, part);
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size = big_oops_buf_sz - hsize;
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if (!kmsg_dump_get_buffer(dumper, true, dst + hsize,
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size, &len))
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break;
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zipped_len = pstore_compress(dst, psinfo->buf,
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hsize + len, psinfo->bufsize);
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if (zipped_len > 0) {
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compressed = true;
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total_len = zipped_len;
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} else {
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compressed = false;
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total_len = copy_kmsg_to_buffer(hsize, len);
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}
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} else {
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dst = psinfo->buf;
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hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount,
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part);
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size = psinfo->bufsize - hsize;
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dst += hsize;
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if (!kmsg_dump_get_buffer(dumper, true, dst,
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size, &len))
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break;
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compressed = false;
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total_len = hsize + len;
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}
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ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
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oopscount, compressed, total_len, psinfo);
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if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
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pstore_new_entry = 1;
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total += total_len;
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part++;
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}
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if (pstore_cannot_block_path(reason)) {
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if (is_locked)
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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} else
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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}
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static struct kmsg_dumper pstore_dumper = {
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.dump = pstore_dump,
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};
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#ifdef CONFIG_PSTORE_CONSOLE
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static void pstore_console_write(struct console *con, const char *s, unsigned c)
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{
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const char *e = s + c;
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while (s < e) {
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unsigned long flags;
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u64 id;
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if (c > psinfo->bufsize)
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c = psinfo->bufsize;
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if (oops_in_progress) {
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if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
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break;
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} else {
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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}
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memcpy(psinfo->buf, s, c);
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psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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s += c;
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c = e - s;
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}
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}
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static struct console pstore_console = {
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.name = "pstore",
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.write = pstore_console_write,
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.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
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.index = -1,
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};
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static void pstore_register_console(void)
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{
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register_console(&pstore_console);
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}
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#else
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static void pstore_register_console(void) {}
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#endif
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static int pstore_write_compat(enum pstore_type_id type,
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enum kmsg_dump_reason reason,
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u64 *id, unsigned int part, int count,
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bool compressed, size_t size,
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struct pstore_info *psi)
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{
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return psi->write_buf(type, reason, id, part, psinfo->buf, compressed,
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size, psi);
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}
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/*
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* platform specific persistent storage driver registers with
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* us here. If pstore is already mounted, call the platform
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* read function right away to populate the file system. If not
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* then the pstore mount code will call us later to fill out
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* the file system.
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*
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* Register with kmsg_dump to save last part of console log on panic.
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*/
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int pstore_register(struct pstore_info *psi)
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{
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struct module *owner = psi->owner;
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if (backend && strcmp(backend, psi->name))
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return -EPERM;
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spin_lock(&pstore_lock);
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if (psinfo) {
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spin_unlock(&pstore_lock);
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return -EBUSY;
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}
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if (!psi->write)
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psi->write = pstore_write_compat;
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psinfo = psi;
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mutex_init(&psinfo->read_mutex);
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spin_unlock(&pstore_lock);
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if (owner && !try_module_get(owner)) {
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psinfo = NULL;
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return -EINVAL;
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}
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allocate_buf_for_compression();
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if (pstore_is_mounted())
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pstore_get_records(0);
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kmsg_dump_register(&pstore_dumper);
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if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) {
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pstore_register_console();
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pstore_register_ftrace();
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}
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if (pstore_update_ms >= 0) {
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pstore_timer.expires = jiffies +
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msecs_to_jiffies(pstore_update_ms);
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add_timer(&pstore_timer);
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}
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pr_info("pstore: Registered %s as persistent store backend\n",
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psi->name);
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return 0;
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}
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EXPORT_SYMBOL_GPL(pstore_register);
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/*
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* Read all the records from the persistent store. Create
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* files in our filesystem. Don't warn about -EEXIST errors
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* when we are re-scanning the backing store looking to add new
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* error records.
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*/
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void pstore_get_records(int quiet)
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{
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struct pstore_info *psi = psinfo;
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char *buf = NULL;
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ssize_t size;
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u64 id;
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int count;
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enum pstore_type_id type;
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struct timespec time;
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int failed = 0, rc;
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bool compressed;
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int unzipped_len = -1;
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if (!psi)
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return;
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mutex_lock(&psi->read_mutex);
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if (psi->open && psi->open(psi))
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goto out;
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while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
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psi)) > 0) {
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if (compressed && (type == PSTORE_TYPE_DMESG)) {
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if (big_oops_buf)
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unzipped_len = pstore_decompress(buf,
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big_oops_buf, size,
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big_oops_buf_sz);
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if (unzipped_len > 0) {
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buf = big_oops_buf;
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size = unzipped_len;
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compressed = false;
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} else {
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pr_err("pstore: decompression failed;"
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"returned %d\n", unzipped_len);
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compressed = true;
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}
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}
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rc = pstore_mkfile(type, psi->name, id, count, buf,
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compressed, (size_t)size, time, psi);
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if (unzipped_len < 0) {
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/* Free buffer other than big oops */
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kfree(buf);
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buf = NULL;
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} else
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unzipped_len = -1;
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if (rc && (rc != -EEXIST || !quiet))
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failed++;
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}
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if (psi->close)
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psi->close(psi);
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out:
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mutex_unlock(&psi->read_mutex);
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if (failed)
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printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
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failed, psi->name);
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}
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static void pstore_dowork(struct work_struct *work)
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{
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pstore_get_records(1);
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}
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static void pstore_timefunc(unsigned long dummy)
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{
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if (pstore_new_entry) {
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|
pstore_new_entry = 0;
|
|
schedule_work(&pstore_work);
|
|
}
|
|
|
|
mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
|
|
}
|
|
|
|
module_param(backend, charp, 0444);
|
|
MODULE_PARM_DESC(backend, "Pstore backend to use");
|