initial_commit

5 files changed, 544 insertions, 0 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
new file mode 100644
index 00000000..8007ae7c
--- /dev/null
+++ b/fs/pstore/Kconfig
@@ -0,0 +1,13 @@
+config PSTORE
+	bool "Persistent store support"
+	default n
+	help
+	   This option enables generic access to platform level
+	   persistent storage via "pstore" filesystem that can
+	   be mounted as /dev/pstore.  Only useful if you have
+	   a platform level driver that registers with pstore to
+	   provide the data, so you probably should just go say "Y"
+	   (or "M") to a platform specific persistent store driver
+	   (e.g. ACPI_APEI on X86) which will select this for you.
+	   If you don't have a platform persistent store driver,
+	   say N.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
new file mode 100644
index 00000000..760f4bce
--- /dev/null
+++ b/fs/pstore/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for the linux pstorefs routines.
+#
+
+obj-y += pstore.o
+
+pstore-objs += inode.o platform.o
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
new file mode 100644
index 00000000..977ed272
--- /dev/null
+++ b/fs/pstore/inode.c
@@ -0,0 +1,311 @@
+/*
+ * Persistent Storage - ramfs 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/module.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/mount.h>
+#include <linux/ramfs.h>
+#include <linux/parser.h>
+#include <linux/sched.h>
+#include <linux/magic.h>
+#include <linux/pstore.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "internal.h"
+
+#define	PSTORE_NAMELEN	64
+
+struct pstore_private {
+	u64	id;
+	int	(*erase)(u64);
+	ssize_t	size;
+	char	data[];
+};
+
+static int pstore_file_open(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return 0;
+}
+
+static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	struct pstore_private *ps = file->private_data;
+
+	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
+}
+
+static const struct file_operations pstore_file_operations = {
+	.open	= pstore_file_open,
+	.read	= pstore_file_read,
+	.llseek	= default_llseek,
+};
+
+/*
+ * When a file is unlinked from our file system we call the
+ * platform driver to erase the record from persistent store.
+ */
+static int pstore_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct pstore_private *p = dentry->d_inode->i_private;
+
+	p->erase(p->id);
+
+	return simple_unlink(dir, dentry);
+}
+
+static void pstore_evict_inode(struct inode *inode)
+{
+	end_writeback(inode);
+	kfree(inode->i_private);
+}
+
+static const struct inode_operations pstore_dir_inode_operations = {
+	.lookup		= simple_lookup,
+	.unlink		= pstore_unlink,
+};
+
+static struct inode *pstore_get_inode(struct super_block *sb,
+					const struct inode *dir, int mode, dev_t dev)
+{
+	struct inode *inode = new_inode(sb);
+
+	if (inode) {
+		inode->i_ino = get_next_ino();
+		inode->i_uid = inode->i_gid = 0;
+		inode->i_mode = mode;
+		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		switch (mode & S_IFMT) {
+		case S_IFREG:
+			inode->i_fop = &pstore_file_operations;
+			break;
+		case S_IFDIR:
+			inode->i_op = &pstore_dir_inode_operations;
+			inode->i_fop = &simple_dir_operations;
+			inc_nlink(inode);
+			break;
+		}
+	}
+	return inode;
+}
+
+enum {
+	Opt_kmsg_bytes, Opt_err
+};
+
+static const match_table_t tokens = {
+	{Opt_kmsg_bytes, "kmsg_bytes=%u"},
+	{Opt_err, NULL}
+};
+
+static void parse_options(char *options)
+{
+	char		*p;
+	substring_t	args[MAX_OPT_ARGS];
+	int		option;
+
+	if (!options)
+		return;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_kmsg_bytes:
+			if (!match_int(&args[0], &option))
+				pstore_set_kmsg_bytes(option);
+			break;
+		}
+	}
+}
+
+static int pstore_remount(struct super_block *sb, int *flags, char *data)
+{
+	parse_options(data);
+
+	return 0;
+}
+
+static const struct super_operations pstore_ops = {
+	.statfs		= simple_statfs,
+	.drop_inode	= generic_delete_inode,
+	.evict_inode	= pstore_evict_inode,
+	.remount_fs	= pstore_remount,
+	.show_options	= generic_show_options,
+};
+
+static struct super_block *pstore_sb;
+
+int pstore_is_mounted(void)
+{
+	return pstore_sb != NULL;
+}
+
+/*
+ * Make a regular file in the root directory of our file system.
+ * Load it up with "size" bytes of data from "buf".
+ * Set the mtime & ctime to the date that this record was originally stored.
+ */
+int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
+			      char *data, size_t size,
+			      struct timespec time, int (*erase)(u64))
+{
+	struct dentry		*root = pstore_sb->s_root;
+	struct dentry		*dentry;
+	struct inode		*inode;
+	int			rc;
+	char			name[PSTORE_NAMELEN];
+	struct pstore_private	*private;
+
+	rc = -ENOMEM;
+	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
+	if (!inode)
+		goto fail;
+	private = kmalloc(sizeof *private + size, GFP_KERNEL);
+	if (!private)
+		goto fail_alloc;
+	private->id = id;
+	private->erase = erase;
+
+	switch (type) {
+	case PSTORE_TYPE_DMESG:
+		sprintf(name, "dmesg-%s-%lld", psname, id);
+		break;
+	case PSTORE_TYPE_MCE:
+		sprintf(name, "mce-%s-%lld", psname, id);
+		break;
+	case PSTORE_TYPE_UNKNOWN:
+		sprintf(name, "unknown-%s-%lld", psname, id);
+		break;
+	default:
+		sprintf(name, "type%d-%s-%lld", type, psname, id);
+		break;
+	}
+
+	mutex_lock(&root->d_inode->i_mutex);
+
+	rc = -ENOSPC;
+	dentry = d_alloc_name(root, name);
+	if (IS_ERR(dentry))
+		goto fail_lockedalloc;
+
+	memcpy(private->data, data, size);
+	inode->i_size = private->size = size;
+
+	inode->i_private = private;
+
+	if (time.tv_sec)
+		inode->i_mtime = inode->i_ctime = time;
+
+	d_add(dentry, inode);
+
+	mutex_unlock(&root->d_inode->i_mutex);
+
+	return 0;
+
+fail_lockedalloc:
+	mutex_unlock(&root->d_inode->i_mutex);
+	kfree(private);
+fail_alloc:
+	iput(inode);
+
+fail:
+	return rc;
+}
+
+int pstore_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct inode *inode = NULL;
+	struct dentry *root;
+	int err;
+
+	save_mount_options(sb, data);
+
+	pstore_sb = sb;
+
+	sb->s_maxbytes		= MAX_LFS_FILESIZE;
+	sb->s_blocksize		= PAGE_CACHE_SIZE;
+	sb->s_blocksize_bits	= PAGE_CACHE_SHIFT;
+	sb->s_magic		= PSTOREFS_MAGIC;
+	sb->s_op		= &pstore_ops;
+	sb->s_time_gran		= 1;
+
+	parse_options(data);
+
+	inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
+	if (!inode) {
+		err = -ENOMEM;
+		goto fail;
+	}
+	/* override ramfs "dir" options so we catch unlink(2) */
+	inode->i_op = &pstore_dir_inode_operations;
+
+	root = d_alloc_root(inode);
+	sb->s_root = root;
+	if (!root) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	pstore_get_records();
+
+	return 0;
+fail:
+	iput(inode);
+	return err;
+}
+
+static struct dentry *pstore_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_single(fs_type, flags, data, pstore_fill_super);
+}
+
+static void pstore_kill_sb(struct super_block *sb)
+{
+	kill_litter_super(sb);
+	pstore_sb = NULL;
+}
+
+static struct file_system_type pstore_fs_type = {
+	.name		= "pstore",
+	.mount		= pstore_mount,
+	.kill_sb	= pstore_kill_sb,
+};
+
+static int __init init_pstore_fs(void)
+{
+	return register_filesystem(&pstore_fs_type);
+}
+module_init(init_pstore_fs)
+
+MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
+MODULE_LICENSE("GPL");
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
new file mode 100644
index 00000000..8c9f23eb
--- /dev/null
+++ b/fs/pstore/internal.h
@@ -0,0 +1,6 @@
+extern void	pstore_set_kmsg_bytes(int);
+extern void	pstore_get_records(void);
+extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
+			      char *data, size_t size,
+			      struct timespec time, int (*erase)(u64));
+extern int	pstore_is_mounted(void);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
new file mode 100644
index 00000000..f2c3ff20
--- /dev/null
+++ b/fs/pstore/platform.c
@@ -0,0 +1,207 @@
+/*
+ * 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 */
+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 char *reason_str[] = {
+	"Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
+};
+
+/*
+ * 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, *why;
+	u64		id;
+	int		hsize, part = 1;
+
+	if (reason < ARRAY_SIZE(reason_str))
+		why = reason_str[reason];
+	else
+		why = "Unknown";
+
+	mutex_lock(&psinfo->buf_mutex);
+	oopscount++;
+	while (total < kmsg_bytes) {
+		dst = psinfo->buf;
+		hsize = sprintf(dst, "%s#%d Part%d\n", why, 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 (reason == KMSG_DUMP_OOPS && 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;
+	ssize_t			size;
+	u64			id;
+	enum pstore_type_id	type;
+	struct timespec		time;
+	int			failed = 0, rc;
+
+	if (!psi)
+		return;
+
+	mutex_lock(&psinfo->buf_mutex);
+	rc = psi->open(psi);
+	if (rc)
+		goto out;
+
+	while ((size = psi->read(&id, &type, &time)) > 0) {
+		if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
+				  time, psi->erase))
+			failed++;
+	}
+	psi->close(psi);
+out:
+	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);