273 lines
6.5 KiB
C
273 lines
6.5 KiB
C
/*
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* Persistent Storage - platform driver interface parts.
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*
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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/module.h>
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#include <linux/pstore.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/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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#define PSTORE_INTERVAL (60 * HZ)
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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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static struct pstore_info *psinfo;
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static char *backend;
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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 char *reason_str[] = {
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"Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
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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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const char *s1, unsigned long l1,
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const char *s2, unsigned long l2)
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{
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unsigned long s1_start, s2_start;
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unsigned long l1_cpy, l2_cpy;
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unsigned long size, total = 0;
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char *dst, *why;
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u64 id;
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int hsize, ret;
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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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if (reason < ARRAY_SIZE(reason_str))
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why = reason_str[reason];
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else
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why = "Unknown";
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if (in_nmi()) {
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is_locked = spin_trylock(&psinfo->buf_lock);
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if (!is_locked)
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pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
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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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dst = psinfo->buf;
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hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
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size = psinfo->bufsize - hsize;
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dst += hsize;
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l2_cpy = min(l2, size);
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l1_cpy = min(l1, size - l2_cpy);
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if (l1_cpy + l2_cpy == 0)
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break;
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s2_start = l2 - l2_cpy;
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s1_start = l1 - l1_cpy;
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memcpy(dst, s1 + s1_start, l1_cpy);
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memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
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ret = psinfo->write(PSTORE_TYPE_DMESG, &id, part,
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hsize + l1_cpy + l2_cpy, 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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l1 -= l1_cpy;
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l2 -= l2_cpy;
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total += l1_cpy + l2_cpy;
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part++;
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}
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if (in_nmi()) {
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if (is_locked)
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spin_unlock(&psinfo->buf_lock);
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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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/*
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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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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 (backend && strcmp(backend, psi->name)) {
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spin_unlock(&pstore_lock);
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return -EINVAL;
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}
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psinfo = psi;
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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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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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pstore_timer.expires = jiffies + PSTORE_INTERVAL;
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add_timer(&pstore_timer);
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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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ssize_t size;
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u64 id;
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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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unsigned long flags;
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if (!psi)
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return;
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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rc = psi->open(psi);
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if (rc)
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goto out;
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while ((size = psi->read(&id, &type, &time, psi)) > 0) {
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rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
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time, psi);
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if (rc && (rc != -EEXIST || !quiet))
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failed++;
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}
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psi->close(psi);
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out:
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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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;
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schedule_work(&pstore_work);
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}
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mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL);
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}
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/*
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* Call platform driver to write a record to the
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* persistent store.
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*/
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int pstore_write(enum pstore_type_id type, char *buf, size_t size)
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{
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u64 id;
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int ret;
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unsigned long flags;
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if (!psinfo)
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return -ENODEV;
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if (size > psinfo->bufsize)
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return -EFBIG;
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spin_lock_irqsave(&psinfo->buf_lock, flags);
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memcpy(psinfo->buf, buf, size);
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ret = psinfo->write(type, &id, 0, size, psinfo);
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if (ret == 0 && pstore_is_mounted())
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pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
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size, CURRENT_TIME, psinfo);
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spin_unlock_irqrestore(&psinfo->buf_lock, flags);
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return 0;
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}
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EXPORT_SYMBOL_GPL(pstore_write);
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module_param(backend, charp, 0444);
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MODULE_PARM_DESC(backend, "Pstore backend to use");
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