diff options
Diffstat (limited to 'fs/pstore/platform.c')
| -rw-r--r-- | fs/pstore/platform.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c new file mode 100644 index 000000000000..705fdf8abf6e --- /dev/null +++ b/fs/pstore/platform.c @@ -0,0 +1,202 @@ +/* + * Persistent Storage - platform driver interface parts. + * + * 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 + */ + +#include <linux/atomic.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/kmsg_dump.h> +#include <linux/module.h> +#include <linux/pstore.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +#include "internal.h" + +/* + * pstore_lock just protects "psinfo" during + * calls to pstore_register() + */ +static DEFINE_SPINLOCK(pstore_lock); +static struct pstore_info *psinfo; + +/* How much of the console log to snapshot. /sys/fs/pstore/kmsg_bytes */ +static unsigned long kmsg_bytes = 10240; + +static ssize_t b_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return snprintf(buf, PAGE_SIZE, "%lu\n", kmsg_bytes); +} + +static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + return (sscanf(buf, "%lu", &kmsg_bytes) > 0) ? count : 0; +} + +struct kobj_attribute pstore_kmsg_bytes_attr = + __ATTR(kmsg_bytes, S_IRUGO | S_IWUSR, b_show, b_store); + +/* Tag each group of saved records with a sequence number */ +static int oopscount; + +/* + * 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, + const char *s1, unsigned long l1, + const char *s2, unsigned long l2) +{ + unsigned long s1_start, s2_start; + unsigned long l1_cpy, l2_cpy; + unsigned long size, total = 0; + char *dst; + u64 id; + int hsize, part = 1; + + mutex_lock(&psinfo->buf_mutex); + oopscount++; + while (total < kmsg_bytes) { + dst = psinfo->buf; + hsize = sprintf(dst, "Oops#%d Part%d\n", oopscount, part++); + size = psinfo->bufsize - hsize; + dst += hsize; + + l2_cpy = min(l2, size); + l1_cpy = min(l1, size - l2_cpy); + + if (l1_cpy + l2_cpy == 0) + break; + + s2_start = l2 - l2_cpy; + s1_start = l1 - l1_cpy; + + memcpy(dst, s1 + s1_start, l1_cpy); + memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); + + id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy); + if (pstore_is_mounted()) + pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, + psinfo->buf, hsize + l1_cpy + l2_cpy, + CURRENT_TIME, psinfo->erase); + l1 -= l1_cpy; + l2 -= l2_cpy; + total += l1_cpy + l2_cpy; + } + mutex_unlock(&psinfo->buf_mutex); +} + +static struct kmsg_dumper pstore_dumper = { + .dump = pstore_dump, +}; + +/* + * 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; + + spin_lock(&pstore_lock); + if (psinfo) { + spin_unlock(&pstore_lock); + return -EBUSY; + } + psinfo = psi; + spin_unlock(&pstore_lock); + + if (owner && !try_module_get(owner)) { + psinfo = NULL; + return -EINVAL; + } + + if (pstore_is_mounted()) + pstore_get_records(); + + kmsg_dump_register(&pstore_dumper); + + return 0; +} +EXPORT_SYMBOL_GPL(pstore_register); + +/* + * Read all the records from the persistent store. Create and + * file files in our filesystem. + */ +void pstore_get_records(void) +{ + struct pstore_info *psi = psinfo; + size_t size; + u64 id; + enum pstore_type_id type; + struct timespec time; + int failed = 0; + + if (!psi) + return; + + mutex_lock(&psinfo->buf_mutex); + while ((size = psi->read(&id, &type, &time)) > 0) { + if (pstore_mkfile(type, psi->name, id, psi->buf, size, + time, psi->erase)) + failed++; + } + mutex_unlock(&psinfo->buf_mutex); + + if (failed) + printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", + failed, psi->name); +} + +/* + * Call platform driver to write a record to the + * persistent store. + */ +int pstore_write(enum pstore_type_id type, char *buf, size_t size) +{ + u64 id; + + if (!psinfo) + return -ENODEV; + + if (size > psinfo->bufsize) + return -EFBIG; + + mutex_lock(&psinfo->buf_mutex); + memcpy(psinfo->buf, buf, size); + id = psinfo->write(type, size); + if (pstore_is_mounted()) + pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, + size, CURRENT_TIME, psinfo->erase); + mutex_unlock(&psinfo->buf_mutex); + + return 0; +} +EXPORT_SYMBOL_GPL(pstore_write); |