blob: b821054ca3ed3030afcb5a6707643d048713a433 [file] [log] [blame]
/*
* Persistent Storage - platform driver interface parts.
*
* Copyright (C) 2007-2008 Google, Inc.
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define pr_fmt(fmt) "pstore: " fmt
#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmsg_dump.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/pstore.h>
#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
#include <linux/lzo.h>
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
#include <linux/lz4.h>
#endif
#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
#include <linux/zstd.h>
#endif
#include <linux/crypto.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/jiffies.h>
#include <linux/workqueue.h>
#include "internal.h"
/*
* We defer making "oops" entries appear in pstore - see
* whether the system is actually still running well enough
* to let someone see the entry
*/
static int pstore_update_ms = -1;
module_param_named(update_ms, pstore_update_ms, int, 0600);
MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
"(default is -1, which means runtime updates are disabled; "
"enabling this option is not safe, it may lead to further "
"corruption on Oopses)");
static int pstore_new_entry;
static void pstore_timefunc(struct timer_list *);
static DEFINE_TIMER(pstore_timer, pstore_timefunc);
static void pstore_dowork(struct work_struct *);
static DECLARE_WORK(pstore_work, pstore_dowork);
/*
* pstore_lock just protects "psinfo" during
* calls to pstore_register()
*/
static DEFINE_SPINLOCK(pstore_lock);
struct pstore_info *psinfo;
static char *backend;
static char *compress =
#ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
CONFIG_PSTORE_COMPRESS_DEFAULT;
#else
NULL;
#endif
/* Compression parameters */
static struct crypto_comp *tfm;
struct pstore_zbackend {
int (*zbufsize)(size_t size);
const char *name;
};
static char *big_oops_buf;
static size_t big_oops_buf_sz;
/* How much of the console log to snapshot */
unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
void pstore_set_kmsg_bytes(int bytes)
{
kmsg_bytes = bytes;
}
/* Tag each group of saved records with a sequence number */
static int oopscount;
static const char *get_reason_str(enum kmsg_dump_reason reason)
{
switch (reason) {
case KMSG_DUMP_PANIC:
return "Panic";
case KMSG_DUMP_OOPS:
return "Oops";
case KMSG_DUMP_EMERG:
return "Emergency";
case KMSG_DUMP_RESTART:
return "Restart";
case KMSG_DUMP_HALT:
return "Halt";
case KMSG_DUMP_POWEROFF:
return "Poweroff";
default:
return "Unknown";
}
}
bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
/*
* In case of NMI path, pstore shouldn't be blocked
* regardless of reason.
*/
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
case KMSG_DUMP_PANIC:
/* Emergency restart shouldn't be blocked by spin lock. */
case KMSG_DUMP_EMERG:
return true;
default:
return false;
}
}
EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
static int zbufsize_deflate(size_t size)
{
size_t cmpr;
switch (size) {
/* buffer range for efivars */
case 1000 ... 2000:
cmpr = 56;
break;
case 2001 ... 3000:
cmpr = 54;
break;
case 3001 ... 3999:
cmpr = 52;
break;
/* buffer range for nvram, erst */
case 4000 ... 10000:
cmpr = 45;
break;
default:
cmpr = 60;
break;
}
return (size * 100) / cmpr;
}
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
static int zbufsize_lzo(size_t size)
{
return lzo1x_worst_compress(size);
}
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
static int zbufsize_lz4(size_t size)
{
return LZ4_compressBound(size);
}
#endif
#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
static int zbufsize_842(size_t size)
{
return size;
}
#endif
#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
static int zbufsize_zstd(size_t size)
{
return ZSTD_compressBound(size);
}
#endif
static const struct pstore_zbackend *zbackend __ro_after_init;
static const struct pstore_zbackend zbackends[] = {
#if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
{
.zbufsize = zbufsize_deflate,
.name = "deflate",
},
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
{
.zbufsize = zbufsize_lzo,
.name = "lzo",
},
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
{
.zbufsize = zbufsize_lz4,
.name = "lz4",
},
#endif
#if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
{
.zbufsize = zbufsize_lz4,
.name = "lz4hc",
},
#endif
#if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
{
.zbufsize = zbufsize_842,
.name = "842",
},
#endif
#if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
{
.zbufsize = zbufsize_zstd,
.name = "zstd",
},
#endif
{ }
};
static int pstore_compress(const void *in, void *out,
unsigned int inlen, unsigned int outlen)
{
int ret;
ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
if (ret) {
pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
return ret;
}
return outlen;
}
static int pstore_decompress(void *in, void *out,
unsigned int inlen, unsigned int outlen)
{
int ret;
ret = crypto_comp_decompress(tfm, in, inlen, out, &outlen);
if (ret) {
pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
return ret;
}
return outlen;
}
static void allocate_buf_for_compression(void)
{
struct crypto_comp *ctx;
int size;
char *buf;
/* Skip if not built-in or compression backend not selected yet. */
if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
return;
/* Skip if no pstore backend yet or compression init already done. */
if (!psinfo || tfm)
return;
if (!crypto_has_comp(zbackend->name, 0, 0)) {
pr_err("Unknown compression: %s\n", zbackend->name);
return;
}
size = zbackend->zbufsize(psinfo->bufsize);
if (size <= 0) {
pr_err("Invalid compression size for %s: %d\n",
zbackend->name, size);
return;
}
buf = kmalloc(size, GFP_KERNEL);
if (!buf) {
pr_err("Failed %d byte compression buffer allocation for: %s\n",
size, zbackend->name);
return;
}
ctx = crypto_alloc_comp(zbackend->name, 0, 0);
if (IS_ERR_OR_NULL(ctx)) {
kfree(buf);
pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
PTR_ERR(ctx));
return;
}
/* A non-NULL big_oops_buf indicates compression is available. */
tfm = ctx;
big_oops_buf_sz = size;
big_oops_buf = buf;
pr_info("Using compression: %s\n", zbackend->name);
}
static void free_buf_for_compression(void)
{
if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm)
crypto_free_comp(tfm);
kfree(big_oops_buf);
big_oops_buf = NULL;
big_oops_buf_sz = 0;
}
/*
* Called when compression fails, since the printk buffer
* would be fetched for compression calling it again when
* compression fails would have moved the iterator of
* printk buffer which results in fetching old contents.
* Copy the recent messages from big_oops_buf to psinfo->buf
*/
static size_t copy_kmsg_to_buffer(int hsize, size_t len)
{
size_t total_len;
size_t diff;
total_len = hsize + len;
if (total_len > psinfo->bufsize) {
diff = total_len - psinfo->bufsize + hsize;
memcpy(psinfo->buf, big_oops_buf, hsize);
memcpy(psinfo->buf + hsize, big_oops_buf + diff,
psinfo->bufsize - hsize);
total_len = psinfo->bufsize;
} else
memcpy(psinfo->buf, big_oops_buf, total_len);
return total_len;
}
void pstore_record_init(struct pstore_record *record,
struct pstore_info *psinfo)
{
memset(record, 0, sizeof(*record));
record->psi = psinfo;
/* Report zeroed timestamp if called before timekeeping has resumed. */
record->time = ns_to_timespec64(ktime_get_real_fast_ns());
}
/*
* callback from kmsg_dump. (s2,l2) has the most recently
* written bytes, older bytes are in (s1,l1). Save as much
* as we can from the end of the buffer.
*/
static void pstore_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
unsigned long total = 0;
const char *why;
unsigned int part = 1;
unsigned long flags = 0;
int is_locked;
int ret;
why = get_reason_str(reason);
if (pstore_cannot_block_path(reason)) {
is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
if (!is_locked) {
pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
, in_nmi() ? "NMI" : why);
return;
}
} else {
spin_lock_irqsave(&psinfo->buf_lock, flags);
is_locked = 1;
}
oopscount++;
while (total < kmsg_bytes) {
char *dst;
size_t dst_size;
int header_size;
int zipped_len = -1;
size_t dump_size;
struct pstore_record record;
pstore_record_init(&record, psinfo);
record.type = PSTORE_TYPE_DMESG;
record.count = oopscount;
record.reason = reason;
record.part = part;
record.buf = psinfo->buf;
if (big_oops_buf && is_locked) {
dst = big_oops_buf;
dst_size = big_oops_buf_sz;
} else {
dst = psinfo->buf;
dst_size = psinfo->bufsize;
}
/* Write dump header. */
header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
oopscount, part);
dst_size -= header_size;
/* Write dump contents. */
if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
dst_size, &dump_size))
break;
if (big_oops_buf && is_locked) {
zipped_len = pstore_compress(dst, psinfo->buf,
header_size + dump_size,
psinfo->bufsize);
if (zipped_len > 0) {
record.compressed = true;
record.size = zipped_len;
} else {
record.size = copy_kmsg_to_buffer(header_size,
dump_size);
}
} else {
record.size = header_size + dump_size;
}
ret = psinfo->write(&record);
if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
pstore_new_entry = 1;
total += record.size;
part++;
}
if (is_locked)
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}
static struct kmsg_dumper pstore_dumper = {
.dump = pstore_dump,
};
/*
* Register with kmsg_dump to save last part of console log on panic.
*/
static void pstore_register_kmsg(void)
{
kmsg_dump_register(&pstore_dumper);
}
static void pstore_unregister_kmsg(void)
{
kmsg_dump_unregister(&pstore_dumper);
}
#ifdef CONFIG_PSTORE_CONSOLE
static void pstore_console_write(struct console *con, const char *s, unsigned c)
{
const char *e = s + c;
while (s < e) {
struct pstore_record record;
unsigned long flags;
pstore_record_init(&record, psinfo);
record.type = PSTORE_TYPE_CONSOLE;
if (c > psinfo->bufsize)
c = psinfo->bufsize;
if (oops_in_progress) {
if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
break;
} else {
spin_lock_irqsave(&psinfo->buf_lock, flags);
}
record.buf = (char *)s;
record.size = c;
psinfo->write(&record);
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
s += c;
c = e - s;
}
}
static struct console pstore_console = {
.name = "pstore",
.write = pstore_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
.index = -1,
};
static void pstore_register_console(void)
{
register_console(&pstore_console);
}
static void pstore_unregister_console(void)
{
unregister_console(&pstore_console);
}
#else
static void pstore_register_console(void) {}
static void pstore_unregister_console(void) {}
#endif
static int pstore_write_user_compat(struct pstore_record *record,
const char __user *buf)
{
int ret = 0;
if (record->buf)
return -EINVAL;
record->buf = memdup_user(buf, record->size);
if (IS_ERR(record->buf)) {
ret = PTR_ERR(record->buf);
goto out;
}
ret = record->psi->write(record);
kfree(record->buf);
out:
record->buf = NULL;
return unlikely(ret < 0) ? ret : record->size;
}
/*
* platform specific persistent storage driver registers with
* us here. If pstore is already mounted, call the platform
* read function right away to populate the file system. If not
* then the pstore mount code will call us later to fill out
* the file system.
*/
int pstore_register(struct pstore_info *psi)
{
struct module *owner = psi->owner;
if (backend && strcmp(backend, psi->name)) {
pr_warn("ignoring unexpected backend '%s'\n", psi->name);
return -EPERM;
}
/* Sanity check flags. */
if (!psi->flags) {
pr_warn("backend '%s' must support at least one frontend\n",
psi->name);
return -EINVAL;
}
/* Check for required functions. */
if (!psi->read || !psi->write) {
pr_warn("backend '%s' must implement read() and write()\n",
psi->name);
return -EINVAL;
}
spin_lock(&pstore_lock);
if (psinfo) {
pr_warn("backend '%s' already loaded: ignoring '%s'\n",
psinfo->name, psi->name);
spin_unlock(&pstore_lock);
return -EBUSY;
}
if (!psi->write_user)
psi->write_user = pstore_write_user_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);
if (owner && !try_module_get(owner)) {
psinfo = NULL;
return -EINVAL;
}
allocate_buf_for_compression();
if (pstore_is_mounted())
pstore_get_records(0);
if (psi->flags & PSTORE_FLAGS_DMESG)
pstore_register_kmsg();
if (psi->flags & PSTORE_FLAGS_CONSOLE)
pstore_register_console();
if (psi->flags & PSTORE_FLAGS_FTRACE)
pstore_register_ftrace();
if (psi->flags & PSTORE_FLAGS_PMSG)
pstore_register_pmsg();
/* Start watching for new records, if desired. */
if (pstore_update_ms >= 0) {
pstore_timer.expires = jiffies +
msecs_to_jiffies(pstore_update_ms);
add_timer(&pstore_timer);
}
/*
* Update the module parameter backend, so it is visible
* through /sys/module/pstore/parameters/backend
*/
backend = psi->name;
pr_info("Registered %s as persistent store backend\n", psi->name);
module_put(owner);
return 0;
}
EXPORT_SYMBOL_GPL(pstore_register);
void pstore_unregister(struct pstore_info *psi)
{
/* Stop timer and make sure all work has finished. */
pstore_update_ms = -1;
del_timer_sync(&pstore_timer);
flush_work(&pstore_work);
if (psi->flags & PSTORE_FLAGS_PMSG)
pstore_unregister_pmsg();
if (psi->flags & PSTORE_FLAGS_FTRACE)
pstore_unregister_ftrace();
if (psi->flags & PSTORE_FLAGS_CONSOLE)
pstore_unregister_console();
if (psi->flags & PSTORE_FLAGS_DMESG)
pstore_unregister_kmsg();
free_buf_for_compression();
psinfo = NULL;
backend = NULL;
}
EXPORT_SYMBOL_GPL(pstore_unregister);
static void decompress_record(struct pstore_record *record)
{
int unzipped_len;
char *decompressed;
if (!record->compressed)
return;
/* Only PSTORE_TYPE_DMESG support compression. */
if (record->type != PSTORE_TYPE_DMESG) {
pr_warn("ignored compressed record type %d\n", record->type);
return;
}
/* No compression method has created the common buffer. */
if (!big_oops_buf) {
pr_warn("no decompression buffer allocated\n");
return;
}
unzipped_len = pstore_decompress(record->buf, big_oops_buf,
record->size, big_oops_buf_sz);
if (unzipped_len <= 0) {
pr_err("decompression failed: %d\n", unzipped_len);
return;
}
/* Build new buffer for decompressed contents. */
decompressed = kmalloc(unzipped_len + record->ecc_notice_size,
GFP_KERNEL);
if (!decompressed) {
pr_err("decompression ran out of memory\n");
return;
}
memcpy(decompressed, big_oops_buf, unzipped_len);
/* Append ECC notice to decompressed buffer. */
memcpy(decompressed + unzipped_len, record->buf + record->size,
record->ecc_notice_size);
/* Swap out compresed contents with decompressed contents. */
kfree(record->buf);
record->buf = decompressed;
record->size = unzipped_len;
record->compressed = false;
}
/*
* Read all the records from one persistent store backend. Create
* files in our filesystem. Don't warn about -EEXIST errors
* when we are re-scanning the backing store looking to add new
* error records.
*/
void pstore_get_backend_records(struct pstore_info *psi,
struct dentry *root, int quiet)
{
int failed = 0;
unsigned int stop_loop = 65536;
if (!psi || !root)
return;
mutex_lock(&psi->read_mutex);
if (psi->open && psi->open(psi))
goto out;
/*
* Backend callback read() allocates record.buf. decompress_record()
* may reallocate record.buf. On success, pstore_mkfile() will keep
* the record.buf, so free it only on failure.
*/
for (; stop_loop; stop_loop--) {
struct pstore_record *record;
int rc;
record = kzalloc(sizeof(*record), GFP_KERNEL);
if (!record) {
pr_err("out of memory creating record\n");
break;
}
pstore_record_init(record, psi);
record->size = psi->read(record);
/* No more records left in backend? */
if (record->size <= 0) {
kfree(record);
break;
}
decompress_record(record);
rc = pstore_mkfile(root, record);
if (rc) {
/* pstore_mkfile() did not take record, so free it. */
kfree(record->buf);
kfree(record);
if (rc != -EEXIST || !quiet)
failed++;
}
}
if (psi->close)
psi->close(psi);
out:
mutex_unlock(&psi->read_mutex);
if (failed)
pr_warn("failed to create %d record(s) from '%s'\n",
failed, psi->name);
if (!stop_loop)
pr_err("looping? Too many records seen from '%s'\n",
psi->name);
}
static void pstore_dowork(struct work_struct *work)
{
pstore_get_records(1);
}
static void pstore_timefunc(struct timer_list *unused)
{
if (pstore_new_entry) {
pstore_new_entry = 0;
schedule_work(&pstore_work);
}
if (pstore_update_ms >= 0)
mod_timer(&pstore_timer,
jiffies + msecs_to_jiffies(pstore_update_ms));
}
void __init pstore_choose_compression(void)
{
const struct pstore_zbackend *step;
if (!compress)
return;
for (step = zbackends; step->name; step++) {
if (!strcmp(compress, step->name)) {
zbackend = step;
return;
}
}
}
static int __init pstore_init(void)
{
int ret;
pstore_choose_compression();
/*
* Check if any pstore backends registered earlier but did not
* initialize compression because crypto was not ready. If so,
* initialize compression now.
*/
allocate_buf_for_compression();
ret = pstore_init_fs();
if (ret)
return ret;
return 0;
}
late_initcall(pstore_init);
static void __exit pstore_exit(void)
{
pstore_exit_fs();
}
module_exit(pstore_exit)
module_param(compress, charp, 0444);
MODULE_PARM_DESC(compress, "Pstore compression to use");
module_param(backend, charp, 0444);
MODULE_PARM_DESC(backend, "Pstore backend to use");
MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
MODULE_LICENSE("GPL");