first commit

1 files changed, 340 insertions, 0 deletions

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
new file mode 100644
index 000000000..4f11f2382
--- /dev/null
+++ b/fs/pstore/platform.c
@@ -0,0 +1,340 @@
+/*
+ * 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
+ */
+
+#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/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;
+
+/* 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);
+
+/*
+ * 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;
+		size_t len;
+
+		dst = psinfo->buf;
+		hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
+		size = psinfo->bufsize - hsize;
+		dst += hsize;
+
+		if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
+			break;
+
+		ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
+				    oopscount, hsize + len, psinfo);
+		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
+			pstore_new_entry = 1;
+
+		total += hsize + 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, 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,
+			       size_t size, struct pstore_info *psi)
+{
+	return psi->write_buf(type, reason, id, part, psinfo->buf, 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;
+
+	spin_lock(&pstore_lock);
+	if (psinfo) {
+		spin_unlock(&pstore_lock);
+		return -EBUSY;
+	}
+
+	if (backend && strcmp(backend, psi->name)) {
+		spin_unlock(&pstore_lock);
+		return -EINVAL;
+	}
+
+	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;
+	}
+
+	if (pstore_is_mounted())
+		pstore_get_records(0);
+
+	kmsg_dump_register(&pstore_dumper);
+	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);
+	}
+
+	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;
+
+	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, psi)) > 0) {
+		rc = pstore_mkfile(type, psi->name, id, count, buf,
+				  (size_t)size, time, psi);
+		kfree(buf);
+		buf = NULL;
+		if (rc && (rc != -EEXIST || !quiet))
+			failed++;
+	}
+	if (psi->close)
+		psi->close(psi);
+out:
+	mutex_unlock(&psi->read_mutex);
+
+	if (failed)
+		printk(KERN_WARNING "pstore: 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");