--- /dev/null
+/*
+ * 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>
+#include <linux/zlib.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/hardirq.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(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");
Code Review / kvmfornfv.git / blobdiff