linux/fs/pstore/platform.c
Joel Fernandes (Google) f0f23e5469 pstore: Map PSTORE_TYPE_* to strings
In later patches we will need to map types to names, so create a
constant table for that which can also be used in different parts of
old and new code. This saves the type in the PRZ which will be useful
in later patches.

Instead of having an explicit PSTORE_TYPE_UNKNOWN, just use ..._MAX.

This includes removing the now redundant filename templates which can use
a single format string. Also, there's no reason to limit the "is it still
compressed?" test to only PSTORE_TYPE_DMESG when building the pstorefs
filename. Records are zero-initialized, so a backend would need to have
explicitly set compressed=1.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2018-12-03 16:52:35 -08:00

850 lines
19 KiB
C

/*
* 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)");
/* Names should be in the same order as the enum pstore_type_id */
static const char * const pstore_type_names[] = {
"dmesg",
"mce",
"console",
"ftrace",
"rtas",
"powerpc-ofw",
"powerpc-common",
"pmsg",
"powerpc-opal",
};
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;
const char *pstore_type_to_name(enum pstore_type_id type)
{
BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
return "unknown";
return pstore_type_names[type];
}
EXPORT_SYMBOL_GPL(pstore_type_to_name);
enum pstore_type_id pstore_name_to_type(const char *name)
{
int i;
for (i = 0; i < PSTORE_TYPE_MAX; i++) {
if (!strcmp(pstore_type_names[i], name))
return i;
}
return PSTORE_TYPE_MAX;
}
EXPORT_SYMBOL_GPL(pstore_name_to_type);
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 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 crash dump 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. Save as much as we can (up to kmsg_bytes) 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)
{
struct pstore_record record;
pstore_record_init(&record, psinfo);
record.type = PSTORE_TYPE_CONSOLE;
record.buf = (char *)s;
record.size = c;
psinfo->write(&record);
}
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 ret;
int unzipped_len;
char *unzipped, *workspace;
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;
}
/* Missing compression buffer means compression was not initialized. */
if (!big_oops_buf) {
pr_warn("no decompression method initialized!\n");
return;
}
/* Allocate enough space to hold max decompression and ECC. */
unzipped_len = big_oops_buf_sz;
workspace = kmalloc(unzipped_len + record->ecc_notice_size,
GFP_KERNEL);
if (!workspace)
return;
/* After decompression "unzipped_len" is almost certainly smaller. */
ret = crypto_comp_decompress(tfm, record->buf, record->size,
workspace, &unzipped_len);
if (ret) {
pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
kfree(workspace);
return;
}
/* Append ECC notice to decompressed buffer. */
memcpy(workspace + unzipped_len, record->buf + record->size,
record->ecc_notice_size);
/* Copy decompressed contents into an minimum-sized allocation. */
unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
GFP_KERNEL);
kfree(workspace);
if (!unzipped)
return;
/* Swap out compressed contents with decompressed contents. */
kfree(record->buf);
record->buf = unzipped;
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");