From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- fs/pstore/platform.c | 547 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 547 insertions(+) create mode 100644 fs/pstore/platform.c (limited to 'fs/pstore/platform.c') diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c new file mode 100644 index 000000000..c4c9a10c5 --- /dev/null +++ b/fs/pstore/platform.c @@ -0,0 +1,547 @@ +/* + * Persistent Storage - platform driver interface parts. + * + * Copyright (C) 2007-2008 Google, Inc. + * Copyright (C) 2010 Intel Corporation + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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(unsigned long); +static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0); + +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; + +/* Compression parameters */ +#define COMPR_LEVEL 6 +#define WINDOW_BITS 12 +#define MEM_LEVEL 4 +static struct z_stream_s stream; + +static char *big_oops_buf; +static size_t big_oops_buf_sz; + +/* How much of the console log to snapshot */ +static unsigned long kmsg_bytes = 10240; + +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); + +/* Derived from logfs_compress() */ +static int pstore_compress(const void *in, void *out, size_t inlen, + size_t outlen) +{ + int err, ret; + + ret = -EIO; + err = zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS, + MEM_LEVEL, Z_DEFAULT_STRATEGY); + if (err != Z_OK) + goto error; + + stream.next_in = in; + stream.avail_in = inlen; + stream.total_in = 0; + stream.next_out = out; + stream.avail_out = outlen; + stream.total_out = 0; + + err = zlib_deflate(&stream, Z_FINISH); + if (err != Z_STREAM_END) + goto error; + + err = zlib_deflateEnd(&stream); + if (err != Z_OK) + goto error; + + if (stream.total_out >= stream.total_in) + goto error; + + ret = stream.total_out; +error: + return ret; +} + +/* Derived from logfs_uncompress */ +static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen) +{ + int err, ret; + + ret = -EIO; + err = zlib_inflateInit2(&stream, WINDOW_BITS); + if (err != Z_OK) + goto error; + + stream.next_in = in; + stream.avail_in = inlen; + stream.total_in = 0; + stream.next_out = out; + stream.avail_out = outlen; + stream.total_out = 0; + + err = zlib_inflate(&stream, Z_FINISH); + if (err != Z_STREAM_END) + goto error; + + err = zlib_inflateEnd(&stream); + if (err != Z_OK) + goto error; + + ret = stream.total_out; +error: + return ret; +} + +static void allocate_buf_for_compression(void) +{ + size_t size; + size_t cmpr; + + switch (psinfo->bufsize) { + /* 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; + } + + big_oops_buf_sz = (psinfo->bufsize * 100) / cmpr; + big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL); + if (big_oops_buf) { + size = max(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL), + zlib_inflate_workspacesize()); + stream.workspace = kmalloc(size, GFP_KERNEL); + if (!stream.workspace) { + pr_err("No memory for compression workspace; skipping compression\n"); + kfree(big_oops_buf); + big_oops_buf = NULL; + } + } else { + pr_err("No memory for uncompressed data; skipping compression\n"); + stream.workspace = NULL; + } + +} + +/* + * 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; +} + +/* + * 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; + u64 id; + unsigned int part = 1; + unsigned long flags = 0; + int is_locked = 0; + 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); + } + } else + spin_lock_irqsave(&psinfo->buf_lock, flags); + oopscount++; + while (total < kmsg_bytes) { + char *dst; + unsigned long size; + int hsize; + int zipped_len = -1; + size_t len; + bool compressed; + size_t total_len; + + if (big_oops_buf) { + dst = big_oops_buf; + hsize = sprintf(dst, "%s#%d Part%u\n", why, + oopscount, part); + size = big_oops_buf_sz - hsize; + + if (!kmsg_dump_get_buffer(dumper, true, dst + hsize, + size, &len)) + break; + + zipped_len = pstore_compress(dst, psinfo->buf, + hsize + len, psinfo->bufsize); + + if (zipped_len > 0) { + compressed = true; + total_len = zipped_len; + } else { + compressed = false; + total_len = copy_kmsg_to_buffer(hsize, len); + } + } else { + dst = psinfo->buf; + hsize = sprintf(dst, "%s#%d Part%u\n", why, oopscount, + part); + size = psinfo->bufsize - hsize; + dst += hsize; + + if (!kmsg_dump_get_buffer(dumper, true, dst, + size, &len)) + break; + + compressed = false; + total_len = hsize + len; + } + + ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part, + oopscount, compressed, total_len, psinfo); + if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted()) + pstore_new_entry = 1; + + total += total_len; + part++; + } + if (pstore_cannot_block_path(reason)) { + if (is_locked) + spin_unlock_irqrestore(&psinfo->buf_lock, flags); + } else + spin_unlock_irqrestore(&psinfo->buf_lock, flags); +} + +static struct kmsg_dumper pstore_dumper = { + .dump = pstore_dump, +}; + +#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) { + unsigned long flags; + u64 id; + + 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); + } + memcpy(psinfo->buf, s, c); + psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo); + 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); +} +#else +static void pstore_register_console(void) {} +#endif + +static int pstore_write_compat(enum pstore_type_id type, + enum kmsg_dump_reason reason, + u64 *id, unsigned int part, int count, + bool compressed, size_t size, + struct pstore_info *psi) +{ + return psi->write_buf(type, reason, id, part, psinfo->buf, compressed, + size, psi); +} + +/* + * 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. + * + * Register with kmsg_dump to save last part of console log on panic. + */ +int pstore_register(struct pstore_info *psi) +{ + struct module *owner = psi->owner; + + if (backend && strcmp(backend, psi->name)) + return -EPERM; + + spin_lock(&pstore_lock); + if (psinfo) { + spin_unlock(&pstore_lock); + return -EBUSY; + } + + if (!psi->write) + psi->write = pstore_write_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); + + kmsg_dump_register(&pstore_dumper); + + if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) { + pstore_register_console(); + pstore_register_ftrace(); + pstore_register_pmsg(); + } + + if (pstore_update_ms >= 0) { + pstore_timer.expires = jiffies + + msecs_to_jiffies(pstore_update_ms); + add_timer(&pstore_timer); + } + + pr_info("Registered %s as persistent store backend\n", psi->name); + + return 0; +} +EXPORT_SYMBOL_GPL(pstore_register); + +/* + * Read all the records from the persistent store. 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_records(int quiet) +{ + struct pstore_info *psi = psinfo; + char *buf = NULL; + ssize_t size; + u64 id; + int count; + enum pstore_type_id type; + struct timespec time; + int failed = 0, rc; + bool compressed; + int unzipped_len = -1; + + if (!psi) + return; + + mutex_lock(&psi->read_mutex); + if (psi->open && psi->open(psi)) + goto out; + + while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed, + psi)) > 0) { + if (compressed && (type == PSTORE_TYPE_DMESG)) { + if (big_oops_buf) + unzipped_len = pstore_decompress(buf, + big_oops_buf, size, + big_oops_buf_sz); + + if (unzipped_len > 0) { + kfree(buf); + buf = big_oops_buf; + size = unzipped_len; + compressed = false; + } else { + pr_err("decompression failed;returned %d\n", + unzipped_len); + compressed = true; + } + } + rc = pstore_mkfile(type, psi->name, id, count, buf, + compressed, (size_t)size, time, psi); + if (unzipped_len < 0) { + /* Free buffer other than big oops */ + kfree(buf); + buf = NULL; + } else + unzipped_len = -1; + if (rc && (rc != -EEXIST || !quiet)) + failed++; + } + if (psi->close) + psi->close(psi); +out: + mutex_unlock(&psi->read_mutex); + + if (failed) + pr_warn("failed to load %d record(s) from '%s'\n", + failed, psi->name); +} + +static void pstore_dowork(struct work_struct *work) +{ + pstore_get_records(1); +} + +static void pstore_timefunc(unsigned long dummy) +{ + if (pstore_new_entry) { + 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"); -- cgit v1.2.3-54-g00ecf