[Mod] 同步v5.10版本Pstore

fs/pstore/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config PSTORE
 	tristate "Persistent store support"
 	select CRYPTO if PSTORE_COMPRESS
@@ -114,18 +115,6 @@ config PSTORE_CONSOLE
 	  When the option is enabled, pstore will log all kernel
 	  messages, even if no oops or panic happened.
 
-config PSTORE_CONSOLE_FORCE
-	bool "Log kernel console messages ignore loglevel setting"
-	depends on PSTORE_CONSOLE
-	help
-	  When the option is enabled, allow all kernel messages
-	  log to the pstore console. Enable this with a kernel bool
-	  parameter like "pstore_con_force=1".
-
-config PSTORE_CONSOLE_FORCE_ON
-	bool "Log kernel console messages ignore loglevel setting on by default"
-	depends on PSTORE_CONSOLE_FORCE
-
 config PSTORE_PMSG
 	bool "Log user space messages"
 	depends on PSTORE
@@ -153,7 +142,6 @@ config PSTORE_RAM
 	tristate "Log panic/oops to a RAM buffer"
 	depends on PSTORE
 	depends on HAS_IOMEM
-	depends on HAVE_MEMBLOCK
 	select REED_SOLOMON
 	select REED_SOLOMON_ENC8
 	select REED_SOLOMON_DEC8
@@ -166,6 +154,116 @@ config PSTORE_RAM
 
 	  For more information, see Documentation/admin-guide/ramoops.rst.
 
+config PSTORE_ZONE
+	tristate
+	depends on PSTORE
+	help
+	  The common layer for pstore/blk (and pstore/ram in the future)
+	  to manage storage in zones.
+
+config PSTORE_BLK
+	tristate "Log panic/oops to a block device"
+	depends on PSTORE
+	depends on BLOCK
+	depends on BROKEN
+	select PSTORE_ZONE
+	default n
+	help
+	  This enables panic and oops message to be logged to a block dev
+	  where it can be read back at some later point.
+
+	  For more information, see Documentation/admin-guide/pstore-blk.rst
+
+	  If unsure, say N.
+
+config PSTORE_BLK_BLKDEV
+	string "block device identifier"
+	depends on PSTORE_BLK
+	default ""
+	help
+	  Which block device should be used for pstore/blk.
+
+	  It accepts the following variants:
+	  1) <hex_major><hex_minor> device number in hexadecimal representation,
+	     with no leading 0x, for example b302.
+	  2) /dev/<disk_name> represents the device name of disk
+	  3) /dev/<disk_name><decimal> represents the device name and number
+	     of partition - device number of disk plus the partition number
+	  4) /dev/<disk_name>p<decimal> - same as the above, this form is
+	     used when disk name of partitioned disk ends with a digit.
+	  5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
+	     unique id of a partition if the partition table provides it.
+	     The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
+	     partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
+	     filled hex representation of the 32-bit "NT disk signature", and PP
+	     is a zero-filled hex representation of the 1-based partition number.
+	  6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation
+	     to a partition with a known unique id.
+	  7) <major>:<minor> major and minor number of the device separated by
+	     a colon.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_KMSG_SIZE
+	int "Size in Kbytes of kmsg dump log to store"
+	depends on PSTORE_BLK
+	default 64
+	help
+	  This just sets size of kmsg dump (oops, panic, etc) log for
+	  pstore/blk. The size is in KB and must be a multiple of 4.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_MAX_REASON
+	int "Maximum kmsg dump reason to store"
+	depends on PSTORE_BLK
+	default 2
+	help
+	  The maximum reason for kmsg dumps to store. The default is
+	  2 (KMSG_DUMP_OOPS), see include/linux/kmsg_dump.h's
+	  enum kmsg_dump_reason for more details.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_PMSG_SIZE
+	int "Size in Kbytes of pmsg to store"
+	depends on PSTORE_BLK
+	depends on PSTORE_PMSG
+	default 64
+	help
+	  This just sets size of pmsg (pmsg_size) for pstore/blk. The size is
+	  in KB and must be a multiple of 4.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_CONSOLE_SIZE
+	int "Size in Kbytes of console log to store"
+	depends on PSTORE_BLK
+	depends on PSTORE_CONSOLE
+	default 64
+	help
+	  This just sets size of console log (console_size) to store via
+	  pstore/blk. The size is in KB and must be a multiple of 4.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
+config PSTORE_BLK_FTRACE_SIZE
+	int "Size in Kbytes of ftrace log to store"
+	depends on PSTORE_BLK
+	depends on PSTORE_FTRACE
+	default 64
+	help
+	  This just sets size of ftrace log (ftrace_size) for pstore/blk. The
+	  size is in KB and must be a multiple of 4.
+
+	  NOTE that, both Kconfig and module parameters can configure
+	  pstore/blk, but module parameters have priority over Kconfig.
+
 config PSTORE_BOOT_LOG
 	bool "Print boot log by linux"
 	depends on PSTORE

fs/pstore/Makefile

@@ -12,3 +12,9 @@ pstore-$(CONFIG_PSTORE_PMSG)	+= pmsg.o
 
 ramoops-objs += ram.o ram_core.o
 obj-$(CONFIG_PSTORE_RAM)	+= ramoops.o
+
+pstore_zone-objs += zone.o
+obj-$(CONFIG_PSTORE_ZONE)	+= pstore_zone.o
+
+pstore_blk-objs += blk.o
+obj-$(CONFIG_PSTORE_BLK)	+= pstore_blk.o

fs/pstore/blk.c

@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implements pstore backend driver that write to block (or non-block) storage
+ * devices, using the pstore/zone API.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "../../block/blk.h"
+#include <linux/blkdev.h>
+#include <linux/string.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/pstore_blk.h>
+#include <linux/mount.h>
+#include <linux/uio.h>
+
+static long kmsg_size = CONFIG_PSTORE_BLK_KMSG_SIZE;
+module_param(kmsg_size, long, 0400);
+MODULE_PARM_DESC(kmsg_size, "kmsg dump record size in kbytes");
+
+static int max_reason = CONFIG_PSTORE_BLK_MAX_REASON;
+module_param(max_reason, int, 0400);
+MODULE_PARM_DESC(max_reason,
+		 "maximum reason for kmsg dump (default 2: Oops and Panic)");
+
+#if IS_ENABLED(CONFIG_PSTORE_PMSG)
+static long pmsg_size = CONFIG_PSTORE_BLK_PMSG_SIZE;
+#else
+static long pmsg_size = -1;
+#endif
+module_param(pmsg_size, long, 0400);
+MODULE_PARM_DESC(pmsg_size, "pmsg size in kbytes");
+
+#if IS_ENABLED(CONFIG_PSTORE_CONSOLE)
+static long console_size = CONFIG_PSTORE_BLK_CONSOLE_SIZE;
+#else
+static long console_size = -1;
+#endif
+module_param(console_size, long, 0400);
+MODULE_PARM_DESC(console_size, "console size in kbytes");
+
+#if IS_ENABLED(CONFIG_PSTORE_FTRACE)
+static long ftrace_size = CONFIG_PSTORE_BLK_FTRACE_SIZE;
+#else
+static long ftrace_size = -1;
+#endif
+module_param(ftrace_size, long, 0400);
+MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes");
+
+static bool best_effort;
+module_param(best_effort, bool, 0400);
+MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require storage driver pstore support, default: off)");
+
+/*
+ * blkdev - the block device to use for pstore storage
+ *
+ * Usually, this will be a partition of a block device.
+ *
+ * blkdev accepts the following variants:
+ * 1) <hex_major><hex_minor> device number in hexadecimal representation,
+ *    with no leading 0x, for example b302.
+ * 2) /dev/<disk_name> represents the device number of disk
+ * 3) /dev/<disk_name><decimal> represents the device number
+ *    of partition - device number of disk plus the partition number
+ * 4) /dev/<disk_name>p<decimal> - same as the above, that form is
+ *    used when disk name of partitioned disk ends on a digit.
+ * 5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
+ *    unique id of a partition if the partition table provides it.
+ *    The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
+ *    partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
+ *    filled hex representation of the 32-bit "NT disk signature", and PP
+ *    is a zero-filled hex representation of the 1-based partition number.
+ * 6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
+ *    a partition with a known unique id.
+ * 7) <major>:<minor> major and minor number of the device separated by
+ *    a colon.
+ */
+static char blkdev[80] = CONFIG_PSTORE_BLK_BLKDEV;
+module_param_string(blkdev, blkdev, 80, 0400);
+MODULE_PARM_DESC(blkdev, "block device for pstore storage");
+
+/*
+ * All globals must only be accessed under the pstore_blk_lock
+ * during the register/unregister functions.
+ */
+static DEFINE_MUTEX(pstore_blk_lock);
+static struct block_device *psblk_bdev;
+static struct pstore_zone_info *pstore_zone_info;
+static pstore_blk_panic_write_op blkdev_panic_write;
+
+struct bdev_info {
+	dev_t devt;
+	sector_t nr_sects;
+	sector_t start_sect;
+};
+
+#define check_size(name, alignsize) ({				\
+	long _##name_ = (name);					\
+	_##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024);	\
+	if (_##name_ & ((alignsize) - 1)) {			\
+		pr_info(#name " must align to %d\n",		\
+				(alignsize));			\
+		_##name_ = ALIGN(name, (alignsize));		\
+	}							\
+	_##name_;						\
+})
+
+static int __register_pstore_device(struct pstore_device_info *dev)
+{
+	int ret;
+
+	lockdep_assert_held(&pstore_blk_lock);
+
+	if (!dev || !dev->total_size || !dev->read || !dev->write)
+		return -EINVAL;
+
+	/* someone already registered before */
+	if (pstore_zone_info)
+		return -EBUSY;
+
+	pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL);
+	if (!pstore_zone_info)
+		return -ENOMEM;
+
+	/* zero means not limit on which backends to attempt to store. */
+	if (!dev->flags)
+		dev->flags = UINT_MAX;
+
+#define verify_size(name, alignsize, enabled) {				\
+		long _##name_;						\
+		if (enabled)						\
+			_##name_ = check_size(name, alignsize);		\
+		else							\
+			_##name_ = 0;					\
+		name = _##name_ / 1024;					\
+		pstore_zone_info->name = _##name_;			\
+	}
+
+	verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG);
+	verify_size(pmsg_size, 4096, dev->flags & PSTORE_FLAGS_PMSG);
+	verify_size(console_size, 4096, dev->flags & PSTORE_FLAGS_CONSOLE);
+	verify_size(ftrace_size, 4096, dev->flags & PSTORE_FLAGS_FTRACE);
+#undef verify_size
+
+	pstore_zone_info->total_size = dev->total_size;
+	pstore_zone_info->max_reason = max_reason;
+	pstore_zone_info->read = dev->read;
+	pstore_zone_info->write = dev->write;
+	pstore_zone_info->erase = dev->erase;
+	pstore_zone_info->panic_write = dev->panic_write;
+	pstore_zone_info->name = KBUILD_MODNAME;
+	pstore_zone_info->owner = THIS_MODULE;
+
+	ret = register_pstore_zone(pstore_zone_info);
+	if (ret) {
+		kfree(pstore_zone_info);
+		pstore_zone_info = NULL;
+	}
+	return ret;
+}
+/**
+ * register_pstore_device() - register non-block device to pstore/blk
+ *
+ * @dev: non-block device information
+ *
+ * Return:
+ * * 0		- OK
+ * * Others	- something error.
+ */
+int register_pstore_device(struct pstore_device_info *dev)
+{
+	int ret;
+
+	mutex_lock(&pstore_blk_lock);
+	ret = __register_pstore_device(dev);
+	mutex_unlock(&pstore_blk_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_pstore_device);
+
+static void __unregister_pstore_device(struct pstore_device_info *dev)
+{
+	lockdep_assert_held(&pstore_blk_lock);
+	if (pstore_zone_info && pstore_zone_info->read == dev->read) {
+		unregister_pstore_zone(pstore_zone_info);
+		kfree(pstore_zone_info);
+		pstore_zone_info = NULL;
+	}
+}
+
+/**
+ * unregister_pstore_device() - unregister non-block device from pstore/blk
+ *
+ * @dev: non-block device information
+ */
+void unregister_pstore_device(struct pstore_device_info *dev)
+{
+	mutex_lock(&pstore_blk_lock);
+	__unregister_pstore_device(dev);
+	mutex_unlock(&pstore_blk_lock);
+}
+EXPORT_SYMBOL_GPL(unregister_pstore_device);
+
+/**
+ * psblk_get_bdev() - open block device
+ *
+ * @holder:	Exclusive holder identifier
+ * @info:	Information about bdev to fill in
+ *
+ * Return: pointer to block device on success and others on error.
+ *
+ * On success, the returned block_device has reference count of one.
+ */
+static struct block_device *psblk_get_bdev(void *holder,
+					   struct bdev_info *info)
+{
+	struct block_device *bdev = ERR_PTR(-ENODEV);
+	fmode_t mode = FMODE_READ | FMODE_WRITE;
+	sector_t nr_sects;
+
+	lockdep_assert_held(&pstore_blk_lock);
+
+	if (pstore_zone_info)
+		return ERR_PTR(-EBUSY);
+
+	if (!blkdev[0])
+		return ERR_PTR(-ENODEV);
+
+	if (holder)
+		mode |= FMODE_EXCL;
+	bdev = blkdev_get_by_path(blkdev, mode, holder);
+	if (IS_ERR(bdev)) {
+		dev_t devt;
+
+		devt = name_to_dev_t(blkdev);
+		if (devt == 0)
+			return ERR_PTR(-ENODEV);
+		bdev = blkdev_get_by_dev(devt, mode, holder);
+		if (IS_ERR(bdev))
+			return bdev;
+	}
+
+	nr_sects = part_nr_sects_read(bdev->bd_part);
+	if (!nr_sects) {
+		pr_err("not enough space for '%s'\n", blkdev);
+		blkdev_put(bdev, mode);
+		return ERR_PTR(-ENOSPC);
+	}
+
+	if (info) {
+		info->devt = bdev->bd_dev;
+		info->nr_sects = nr_sects;
+		info->start_sect = get_start_sect(bdev);
+	}
+
+	return bdev;
+}
+
+static void psblk_put_bdev(struct block_device *bdev, void *holder)
+{
+	fmode_t mode = FMODE_READ | FMODE_WRITE;
+
+	lockdep_assert_held(&pstore_blk_lock);
+
+	if (!bdev)
+		return;
+
+	if (holder)
+		mode |= FMODE_EXCL;
+	blkdev_put(bdev, mode);
+}
+
+static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
+{
+	struct block_device *bdev = psblk_bdev;
+	struct file file;
+	struct kiocb kiocb;
+	struct iov_iter iter;
+	struct kvec iov = {.iov_base = buf, .iov_len = bytes};
+
+	if (!bdev)
+		return -ENODEV;
+
+	memset(&file, 0, sizeof(struct file));
+	file.f_mapping = bdev->bd_inode->i_mapping;
+	file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
+	file.f_inode = bdev->bd_inode;
+	file_ra_state_init(&file.f_ra, file.f_mapping);
+
+	init_sync_kiocb(&kiocb, &file);
+	kiocb.ki_pos = pos;
+	iov_iter_kvec(&iter, READ, &iov, 1, bytes);
+
+	return generic_file_read_iter(&kiocb, &iter);
+}
+
+static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
+		loff_t pos)
+{
+	struct block_device *bdev = psblk_bdev;
+	struct iov_iter iter;
+	struct kiocb kiocb;
+	struct file file;
+	ssize_t ret;
+	struct kvec iov = {.iov_base = (void *)buf, .iov_len = bytes};
+
+	if (!bdev)
+		return -ENODEV;
+
+	/* Console/Ftrace backend may handle buffer until flush dirty zones */
+	if (in_interrupt() || irqs_disabled())
+		return -EBUSY;
+
+	memset(&file, 0, sizeof(struct file));
+	file.f_mapping = bdev->bd_inode->i_mapping;
+	file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME;
+	file.f_inode = bdev->bd_inode;
+
+	init_sync_kiocb(&kiocb, &file);
+	kiocb.ki_pos = pos;
+	iov_iter_kvec(&iter, WRITE, &iov, 1, bytes);
+
+	inode_lock(bdev->bd_inode);
+	ret = generic_write_checks(&kiocb, &iter);
+	if (ret > 0)
+		ret = generic_perform_write(&file, &iter, pos);
+	inode_unlock(bdev->bd_inode);
+
+	if (likely(ret > 0)) {
+		const struct file_operations f_op = {.fsync = blkdev_fsync};
+
+		file.f_op = &f_op;
+		kiocb.ki_pos += ret;
+		ret = generic_write_sync(&kiocb, ret);
+	}
+	return ret;
+}
+
+static ssize_t psblk_blk_panic_write(const char *buf, size_t size,
+		loff_t off)
+{
+	int ret;
+
+	if (!blkdev_panic_write)
+		return -EOPNOTSUPP;
+
+	/* size and off must align to SECTOR_SIZE for block device */
+	ret = blkdev_panic_write(buf, off >> SECTOR_SHIFT,
+			size >> SECTOR_SHIFT);
+	/* try next zone */
+	if (ret == -ENOMSG)
+		return ret;
+	return ret ? -EIO : size;
+}
+
+static int __register_pstore_blk(struct pstore_blk_info *info)
+{
+	char bdev_name[BDEVNAME_SIZE];
+	struct block_device *bdev;
+	struct pstore_device_info dev;
+	struct bdev_info binfo;
+	void *holder = blkdev;
+	int ret = -ENODEV;
+
+	lockdep_assert_held(&pstore_blk_lock);
+
+	/* hold bdev exclusively */
+	memset(&binfo, 0, sizeof(binfo));
+	bdev = psblk_get_bdev(holder, &binfo);
+	if (IS_ERR(bdev)) {
+		pr_err("failed to open '%s'!\n", blkdev);
+		return PTR_ERR(bdev);
+	}
+
+	/* only allow driver matching the @blkdev */
+	if (!binfo.devt || (!best_effort &&
+			    MAJOR(binfo.devt) != info->major)) {
+		pr_debug("invalid major %u (expect %u)\n",
+				info->major, MAJOR(binfo.devt));
+		ret = -ENODEV;
+		goto err_put_bdev;
+	}
+
+	/* psblk_bdev must be assigned before register to pstore/blk */
+	psblk_bdev = bdev;
+	blkdev_panic_write = info->panic_write;
+
+	/* Copy back block device details. */
+	info->devt = binfo.devt;
+	info->nr_sects = binfo.nr_sects;
+	info->start_sect = binfo.start_sect;
+
+	memset(&dev, 0, sizeof(dev));
+	dev.total_size = info->nr_sects << SECTOR_SHIFT;
+	dev.flags = info->flags;
+	dev.read = psblk_generic_blk_read;
+	dev.write = psblk_generic_blk_write;
+	dev.erase = NULL;
+	dev.panic_write = info->panic_write ? psblk_blk_panic_write : NULL;
+
+	ret = __register_pstore_device(&dev);
+	if (ret)
+		goto err_put_bdev;
+
+	bdevname(bdev, bdev_name);
+	pr_info("attached %s%s\n", bdev_name,
+		info->panic_write ? "" : " (no dedicated panic_write!)");
+	return 0;
+
+err_put_bdev:
+	psblk_bdev = NULL;
+	blkdev_panic_write = NULL;
+	psblk_put_bdev(bdev, holder);
+	return ret;
+}
+
+/**
+ * register_pstore_blk() - register block device to pstore/blk
+ *
+ * @info: details on the desired block device interface
+ *
+ * Return:
+ * * 0		- OK
+ * * Others	- something error.
+ */
+int register_pstore_blk(struct pstore_blk_info *info)
+{
+	int ret;
+
+	mutex_lock(&pstore_blk_lock);
+	ret = __register_pstore_blk(info);
+	mutex_unlock(&pstore_blk_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_pstore_blk);
+
+static void __unregister_pstore_blk(unsigned int major)
+{
+	struct pstore_device_info dev = { .read = psblk_generic_blk_read };
+	void *holder = blkdev;
+
+	lockdep_assert_held(&pstore_blk_lock);
+	if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) {
+		__unregister_pstore_device(&dev);
+		psblk_put_bdev(psblk_bdev, holder);
+		blkdev_panic_write = NULL;
+		psblk_bdev = NULL;
+	}
+}
+
+/**
+ * unregister_pstore_blk() - unregister block device from pstore/blk
+ *
+ * @major: the major device number of device
+ */
+void unregister_pstore_blk(unsigned int major)
+{
+	mutex_lock(&pstore_blk_lock);
+	__unregister_pstore_blk(major);
+	mutex_unlock(&pstore_blk_lock);
+}
+EXPORT_SYMBOL_GPL(unregister_pstore_blk);
+
+/* get information of pstore/blk */
+int pstore_blk_get_config(struct pstore_blk_config *info)
+{
+	strncpy(info->device, blkdev, 80);
+	info->max_reason = max_reason;
+	info->kmsg_size = check_size(kmsg_size, 4096);
+	info->pmsg_size = check_size(pmsg_size, 4096);
+	info->ftrace_size = check_size(ftrace_size, 4096);
+	info->console_size = check_size(console_size, 4096);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_blk_get_config);
+
+static int __init pstore_blk_init(void)
+{
+	struct pstore_blk_info info = { };
+	int ret = 0;
+
+	mutex_lock(&pstore_blk_lock);
+	if (!pstore_zone_info && best_effort && blkdev[0])
+		ret = __register_pstore_blk(&info);
+	mutex_unlock(&pstore_blk_lock);
+
+	return ret;
+}
+late_initcall(pstore_blk_init);
+
+static void __exit pstore_blk_exit(void)
+{
+	mutex_lock(&pstore_blk_lock);
+	if (psblk_bdev)
+		__unregister_pstore_blk(MAJOR(psblk_bdev->bd_dev));
+	else {
+		struct pstore_device_info dev = { };
+
+		if (pstore_zone_info)
+			dev.read = pstore_zone_info->read;
+		__unregister_pstore_device(&dev);
+	}
+	mutex_unlock(&pstore_blk_lock);
+}
+module_exit(pstore_blk_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>");
+MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
+MODULE_DESCRIPTION("pstore backend for block devices");

fs/pstore/ftrace.c

@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2012  Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
  */
 
 #include <linux/kernel.h>
@@ -24,6 +16,7 @@
 #include <linux/debugfs.h>
 #include <linux/err.h>
 #include <linux/cache.h>
+#include <linux/slab.h>
 #include <asm/barrier.h>
 #include "internal.h"
 
@@ -120,27 +113,13 @@ static struct dentry *pstore_ftrace_dir;
 
 void pstore_register_ftrace(void)
 {
-	struct dentry *file;
-
 	if (!psinfo->write)
 		return;
 
 	pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
-	if (!pstore_ftrace_dir) {
-		pr_err("%s: unable to create pstore directory\n", __func__);
-		return;
-	}
 
-	file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
+	debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
-				   NULL, &pstore_knob_fops);
+			    &pstore_knob_fops);
-	if (!file) {
-		pr_err("%s: unable to create record_ftrace file\n", __func__);
-		goto err_file;
-	}
-
-	return;
-err_file:
-	debugfs_remove(pstore_ftrace_dir);
 }
 
 void pstore_unregister_ftrace(void)
@@ -148,9 +127,62 @@ void pstore_unregister_ftrace(void)
 	mutex_lock(&pstore_ftrace_lock);
 	if (pstore_ftrace_enabled) {
 		unregister_ftrace_function(&pstore_ftrace_ops);
-		pstore_ftrace_enabled = 0;
+		pstore_ftrace_enabled = false;
 	}
 	mutex_unlock(&pstore_ftrace_lock);
 
 	debugfs_remove_recursive(pstore_ftrace_dir);
 }
+
+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+				  const char *src_log, size_t src_log_size)
+{
+	size_t dest_size, src_size, total, dest_off, src_off;
+	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
+	void *merged_buf;
+	struct pstore_ftrace_record *drec, *srec, *mrec;
+	size_t record_size = sizeof(struct pstore_ftrace_record);
+
+	dest_off = *dest_log_size % record_size;
+	dest_size = *dest_log_size - dest_off;
+
+	src_off = src_log_size % record_size;
+	src_size = src_log_size - src_off;
+
+	total = dest_size + src_size;
+	merged_buf = kmalloc(total, GFP_KERNEL);
+	if (!merged_buf)
+		return -ENOMEM;
+
+	drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
+	srec = (struct pstore_ftrace_record *)(src_log + src_off);
+	mrec = (struct pstore_ftrace_record *)(merged_buf);
+
+	while (dest_size > 0 && src_size > 0) {
+		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
+		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
+			mrec[merged_idx++] = drec[dest_idx++];
+			dest_size -= record_size;
+		} else {
+			mrec[merged_idx++] = srec[src_idx++];
+			src_size -= record_size;
+		}
+	}
+
+	while (dest_size > 0) {
+		mrec[merged_idx++] = drec[dest_idx++];
+		dest_size -= record_size;
+	}
+
+	while (src_size > 0) {
+		mrec[merged_idx++] = srec[src_idx++];
+		src_size -= record_size;
+	}
+
+	kfree(*dest_log);
+	*dest_log = merged_buf;
+	*dest_log_size = total;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);

fs/pstore/inode.c

@@ -1,20 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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>
@@ -34,7 +22,6 @@
 #include <linux/magic.h>
 #include <linux/pstore.h>
 #include <linux/slab.h>
-#include <linux/spinlock.h>
 #include <linux/uaccess.h>
 
 #ifdef CONFIG_PSTORE_BOOT_LOG
@@ -46,11 +33,15 @@
 
 #define	PSTORE_NAMELEN	64
 
-static DEFINE_SPINLOCK(allpstore_lock);
+static DEFINE_MUTEX(records_list_lock);
-static LIST_HEAD(allpstore);
+static LIST_HEAD(records_list);
+
+static DEFINE_MUTEX(pstore_sb_lock);
+static struct super_block *pstore_sb;
 
 struct pstore_private {
 	struct list_head list;
+	struct dentry *dentry;
 	struct pstore_record *record;
 	size_t total_size;
 };
@@ -123,7 +114,7 @@ static int pstore_ftrace_seq_show(struct seq_file *s, void *v)
 
 	rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
 
-	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %pf <- %pF\n",
+	seq_printf(s, "CPU:%d ts:%llu %08lx  %08lx  %ps <- %pS\n",
 		   pstore_ftrace_decode_cpu(rec),
 		   pstore_ftrace_read_timestamp(rec),
 		   rec->ip, rec->parent_ip, (void *)rec->ip,
@@ -145,39 +136,13 @@ static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
 	struct seq_file *sf = file->private_data;
 	struct pstore_private *ps = sf->private;
 #ifdef CONFIG_PSTORE_BOOT_LOG
+	size_t size = 0;
 	struct pstore_record *record = ps->record;
-	struct ramoops_context *cxt = record->psi->data;
-	struct persistent_ram_zone *prz;
-	struct persistent_ram_buffer *buffer;
-	char *log_tmp;
-	size_t size, start, n;
 
-	if (ps->record->type == PSTORE_TYPE_BOOT_LOG) {
+	if (record->type == PSTORE_TYPE_BOOT_LOG) {
-
+		size = ramoops_pstore_read_for_boot_log(ps->record);
-		if (!cxt)
+		size = simple_read_from_buffer(userbuf, count, ppos, record->buf, size);
-			return count;
+		return size;
-
-		prz = cxt->boot_przs[record->id];
-
-		if (!prz)
-			return count;
-
-		buffer = prz->buffer;
-		if (!buffer)
-			return count;
-
-		size = atomic_read(&buffer->size);
-		start = atomic_read(&buffer->start);
-
-		log_tmp = kmalloc(size, GFP_KERNEL);
-		if (!log_tmp)
-			return count;
-		memcpy_fromio(log_tmp, &buffer->data[start], size - start);
-		memcpy_fromio(log_tmp + size - start, &buffer->data[0], start);
-
-		n = simple_read_from_buffer(userbuf, count, ppos, log_tmp, size);
-		kfree(log_tmp);
-		return n;
 	}
 #endif
 	if (ps->record->type == PSTORE_TYPE_FTRACE)
@@ -230,10 +195,22 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct pstore_private *p = d_inode(dentry)->i_private;
 	struct pstore_record *record = p->record;
+	int rc = 0;
 
 	if (!record->psi->erase)
 		return -EPERM;
 
+	/* Make sure we can't race while removing this file. */
+	mutex_lock(&records_list_lock);
+	if (!list_empty(&p->list))
+		list_del_init(&p->list);
+	else
+		rc = -ENOENT;
+	p->dentry = NULL;
+	mutex_unlock(&records_list_lock);
+	if (rc)
+		return rc;
+
 	mutex_lock(&record->psi->read_mutex);
 	record->psi->erase(record);
 	mutex_unlock(&record->psi->read_mutex);
@@ -244,15 +221,9 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 static void pstore_evict_inode(struct inode *inode)
 {
 	struct pstore_private	*p = inode->i_private;
-	unsigned long		flags;
 
 	clear_inode(inode);
-	if (p) {
+	free_pstore_private(p);
-		spin_lock_irqsave(&allpstore_lock, flags);
-		list_del(&p->list);
-		spin_unlock_irqrestore(&allpstore_lock, flags);
-		free_pstore_private(p);
-	}
 }
 
 static const struct inode_operations pstore_dir_inode_operations = {
@@ -330,11 +301,54 @@ static const struct super_operations pstore_ops = {
 	.show_options	= pstore_show_options,
 };
 
-static struct super_block *pstore_sb;
+static struct dentry *psinfo_lock_root(void)
-
-bool pstore_is_mounted(void)
 {
-	return pstore_sb != NULL;
+	struct dentry *root;
+
+	mutex_lock(&pstore_sb_lock);
+	/*
+	 * Having no backend is fine -- no records appear.
+	 * Not being mounted is fine -- nothing to do.
+	 */
+	if (!psinfo || !pstore_sb) {
+		mutex_unlock(&pstore_sb_lock);
+		return NULL;
+	}
+
+	root = pstore_sb->s_root;
+	inode_lock(d_inode(root));
+	mutex_unlock(&pstore_sb_lock);
+
+	return root;
+}
+
+int pstore_put_backend_records(struct pstore_info *psi)
+{
+	struct pstore_private *pos, *tmp;
+	struct dentry *root;
+	int rc = 0;
+
+	root = psinfo_lock_root();
+	if (!root)
+		return 0;
+
+	mutex_lock(&records_list_lock);
+	list_for_each_entry_safe(pos, tmp, &records_list, list) {
+		if (pos->record->psi == psi) {
+			list_del_init(&pos->list);
+			rc = simple_unlink(d_inode(root), pos->dentry);
+			if (WARN_ON(rc))
+				break;
+			d_drop(pos->dentry);
+			dput(pos->dentry);
+			pos->dentry = NULL;
+		}
+	}
+	mutex_unlock(&records_list_lock);
+
+	inode_unlock(d_inode(root));
+
+	return rc;
 }
 
 /*
@@ -349,23 +363,20 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 	int			rc = 0;
 	char			name[PSTORE_NAMELEN];
 	struct pstore_private	*private, *pos;
-	unsigned long		flags;
 	size_t			size = record->size + record->ecc_notice_size;
 
-	WARN_ON(!inode_is_locked(d_inode(root)));
+	if (WARN_ON(!inode_is_locked(d_inode(root))))
+		return -EINVAL;
 
-	spin_lock_irqsave(&allpstore_lock, flags);
+	rc = -EEXIST;
-	list_for_each_entry(pos, &allpstore, list) {
+	/* Skip records that are already present in the filesystem. */
+	mutex_lock(&records_list_lock);
+	list_for_each_entry(pos, &records_list, list) {
 		if (pos->record->type == record->type &&
 		    pos->record->id == record->id &&
-		    pos->record->psi == record->psi) {
+		    pos->record->psi == record->psi)
-			rc = -EEXIST;
+			goto fail;
-			break;
-		}
 	}
-	spin_unlock_irqrestore(&allpstore_lock, flags);
-	if (rc)
-		return rc;
 
 	rc = -ENOMEM;
 	inode = pstore_get_inode(root->d_sb);
@@ -373,59 +384,10 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 		goto fail;
 	inode->i_mode = S_IFREG | 0444;
 	inode->i_fop = &pstore_file_operations;
-
+	scnprintf(name, sizeof(name), "%s-%s-%llu%s",
-	switch (record->type) {
+			pstore_type_to_name(record->type),
-	case PSTORE_TYPE_DMESG:
+			record->psi->name, record->id,
-		scnprintf(name, sizeof(name), "dmesg-%s-%llu%s",
+			record->compressed ? ".enc.z" : "");
-			  record->psi->name, record->id,
-			  record->compressed ? ".enc.z" : "");
-		break;
-	case PSTORE_TYPE_CONSOLE:
-		scnprintf(name, sizeof(name), "console-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_FTRACE:
-		scnprintf(name, sizeof(name), "ftrace-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_MCE:
-		scnprintf(name, sizeof(name), "mce-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_RTAS:
-		scnprintf(name, sizeof(name), "rtas-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_OF:
-		scnprintf(name, sizeof(name), "powerpc-ofw-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_COMMON:
-		scnprintf(name, sizeof(name), "powerpc-common-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PMSG:
-		scnprintf(name, sizeof(name), "pmsg-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	case PSTORE_TYPE_PPC_OPAL:
-		scnprintf(name, sizeof(name), "powerpc-opal-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-#ifdef CONFIG_PSTORE_BOOT_LOG
-	case PSTORE_TYPE_BOOT_LOG:
-		scnprintf(name, sizeof(name), "boot-log-%llu", record->id);
-		break;
-#endif
-	case PSTORE_TYPE_UNKNOWN:
-		scnprintf(name, sizeof(name), "unknown-%s-%llu",
-			  record->psi->name, record->id);
-		break;
-	default:
-		scnprintf(name, sizeof(name), "type%d-%s-%llu",
-			  record->type, record->psi->name, record->id);
-		break;
-	}
 
 	private = kzalloc(sizeof(*private), GFP_KERNEL);
 	if (!private)
@@ -435,6 +397,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 	if (!dentry)
 		goto fail_private;
 
+	private->dentry = dentry;
 	private->record = record;
 	inode->i_size = private->total_size = size;
 	inode->i_private = private;
@@ -444,9 +407,8 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
 
 	d_add(dentry, inode);
 
-	spin_lock_irqsave(&allpstore_lock, flags);
+	list_add(&private->list, &records_list);
-	list_add(&private->list, &allpstore);
+	mutex_unlock(&records_list_lock);
-	spin_unlock_irqrestore(&allpstore_lock, flags);
 
 	return 0;
 
@@ -454,8 +416,8 @@ fail_private:
 	free_pstore_private(private);
 fail_inode:
 	iput(inode);
-
 fail:
+	mutex_unlock(&records_list_lock);
 	return rc;
 }
 
@@ -467,16 +429,13 @@ fail:
  */
 void pstore_get_records(int quiet)
 {
-	struct pstore_info *psi = psinfo;
 	struct dentry *root;
 
-	if (!psi || !pstore_sb)
+	root = psinfo_lock_root();
+	if (!root)
 		return;
 
-	root = pstore_sb->s_root;
+	pstore_get_backend_records(psinfo, root, quiet);
-
-	inode_lock(d_inode(root));
-	pstore_get_backend_records(psi, root, quiet);
 	inode_unlock(d_inode(root));
 }
 
@@ -484,8 +443,6 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *inode;
 
-	pstore_sb = sb;
-
 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
 	sb->s_blocksize		= PAGE_SIZE;
 	sb->s_blocksize_bits	= PAGE_SHIFT;
@@ -506,6 +463,10 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
 	if (!sb->s_root)
 		return -ENOMEM;
 
+	mutex_lock(&pstore_sb_lock);
+	pstore_sb = sb;
+	mutex_unlock(&pstore_sb_lock);
+
 	pstore_get_records(0);
 
 	return 0;
@@ -519,8 +480,17 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
 
 static void pstore_kill_sb(struct super_block *sb)
 {
+	mutex_lock(&pstore_sb_lock);
+	WARN_ON(pstore_sb && pstore_sb != sb);
+
 	kill_litter_super(sb);
 	pstore_sb = NULL;
+
+	mutex_lock(&records_list_lock);
+	INIT_LIST_HEAD(&records_list);
+	mutex_unlock(&records_list_lock);
+
+	mutex_unlock(&pstore_sb_lock);
 }
 
 static struct file_system_type pstore_fs_type = {

fs/pstore/internal.h

@@ -12,9 +12,18 @@ extern unsigned long kmsg_bytes;
 #ifdef CONFIG_PSTORE_FTRACE
 extern void pstore_register_ftrace(void);
 extern void pstore_unregister_ftrace(void);
+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+				  const char *src_log, size_t src_log_size);
 #else
 static inline void pstore_register_ftrace(void) {}
 static inline void pstore_unregister_ftrace(void) {}
+static inline ssize_t
+pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+			  const char *src_log, size_t src_log_size)
+{
+	*dest_log_size = 0;
+	return 0;
+}
 #endif
 
 #ifdef CONFIG_PSTORE_PMSG
@@ -31,9 +40,9 @@ extern void	pstore_set_kmsg_bytes(int);
 extern void	pstore_get_records(int);
 extern void	pstore_get_backend_records(struct pstore_info *psi,
 					   struct dentry *root, int quiet);
+extern int	pstore_put_backend_records(struct pstore_info *psi);
 extern int	pstore_mkfile(struct dentry *root,
 			      struct pstore_record *record);
-extern bool	pstore_is_mounted(void);
 extern void	pstore_record_init(struct pstore_record *record,
 				   struct pstore_info *psi);
 

fs/pstore/platform.c

@@ -1,21 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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
@@ -56,9 +44,25 @@ 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 "
+		 "enabling this option may not be safe; it may lead to further "
 		 "corruption on Oopses)");
 
+/* Names should be in the same order as the enum pstore_type_id */
+static const char * const pstore_type_names[] = {
+	"dmesg",
+	"mce",
+	"console",
+	"ftrace",
+	"rtas",
+	"powerpc-ofw",
+	"powerpc-common",
+	"pmsg",
+	"powerpc-opal",
+#ifdef CONFIG_PSTORE_BOOT_LOG
+	"boot-log",
+#endif
+};
+
 static int pstore_new_entry;
 
 static void pstore_timefunc(struct timer_list *);
@@ -68,19 +72,25 @@ static void pstore_dowork(struct work_struct *);
 static DECLARE_WORK(pstore_work, pstore_dowork);
 
 /*
- * pstore_lock just protects "psinfo" during
+ * psinfo_lock protects "psinfo" during calls to
- * calls to pstore_register()
+ * pstore_register(), pstore_unregister(), and
+ * the filesystem mount/unmount routines.
  */
-static DEFINE_SPINLOCK(pstore_lock);
+static DEFINE_MUTEX(psinfo_lock);
 struct pstore_info *psinfo;
 
 static char *backend;
+module_param(backend, charp, 0444);
+MODULE_PARM_DESC(backend, "specific backend to use");
+
 static char *compress =
 #ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
 		CONFIG_PSTORE_COMPRESS_DEFAULT;
 #else
 		NULL;
 #endif
+module_param(compress, charp, 0444);
+MODULE_PARM_DESC(compress, "compression to use");
 
 /* Compression parameters */
 static struct crypto_comp *tfm;
@@ -104,24 +114,36 @@ void pstore_set_kmsg_bytes(int 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)
+const char *pstore_type_to_name(enum pstore_type_id type)
 {
-	switch (reason) {
+	BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
-	case KMSG_DUMP_PANIC:
+
-		return "Panic";
+	if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
-	case KMSG_DUMP_OOPS:
+		return "unknown";
-		return "Oops";
+
-	case KMSG_DUMP_EMERG:
+	return pstore_type_names[type];
-		return "Emergency";
+}
-	case KMSG_DUMP_RESTART:
+EXPORT_SYMBOL_GPL(pstore_type_to_name);
-		return "Restart";
+
-	case KMSG_DUMP_HALT:
+enum pstore_type_id pstore_name_to_type(const char *name)
-		return "Halt";
+{
-	case KMSG_DUMP_POWEROFF:
+	int i;
-		return "Poweroff";
+
-	default:
+	for (i = 0; i < PSTORE_TYPE_MAX; i++) {
-		return "Unknown";
+		if (!strcmp(pstore_type_names[i], name))
+			return i;
 	}
+
+	return PSTORE_TYPE_MAX;
+}
+EXPORT_SYMBOL_GPL(pstore_name_to_type);
+
+static void pstore_timer_kick(void)
+{
+	if (pstore_update_ms < 0)
+		return;
+
+	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
 }
 
 /*
@@ -262,20 +284,6 @@ static int pstore_compress(const void *in, void *out,
 	return outlen;
 }
 
-static int pstore_decompress(void *in, void *out,
-			     unsigned int inlen, unsigned int outlen)
-{
-	int ret;
-
-	ret = crypto_comp_decompress(tfm, in, inlen, out, &outlen);
-	if (ret) {
-		pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
-		return ret;
-	}
-
-	return outlen;
-}
-
 static void allocate_buf_for_compression(void)
 {
 	struct crypto_comp *ctx;
@@ -322,7 +330,7 @@ static void allocate_buf_for_compression(void)
 	big_oops_buf_sz = size;
 	big_oops_buf = buf;
 
-	pr_info("Using compression: %s\n", zbackend->name);
+	pr_info("Using crash dump compression: %s\n", zbackend->name);
 }
 
 static void free_buf_for_compression(void)
@@ -374,9 +382,8 @@ void pstore_record_init(struct pstore_record *record,
 }
 
 /*
- * callback from kmsg_dump. (s2,l2) has the most recently
+ * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
- * written bytes, older bytes are in (s1,l1). Save as much
+ * end of the buffer.
- * as we can from the end of the buffer.
  */
 static void pstore_dump(struct kmsg_dumper *dumper,
 			enum kmsg_dump_reason reason)
@@ -386,7 +393,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 	unsigned int	part = 1;
 	int		ret;
 
-	why = get_reason_str(reason);
+	why = kmsg_dump_reason_str(reason);
 
 	if (down_trylock(&psinfo->buf_lock)) {
 		/* Failed to acquire lock: give up if we cannot wait. */
@@ -452,8 +459,10 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		}
 
 		ret = psinfo->write(&record);
-		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
+		if (ret == 0 && reason == KMSG_DUMP_OOPS) {
 			pstore_new_entry = 1;
+			pstore_timer_kick();
+		}
 
 		total += record.size;
 		part++;
@@ -484,6 +493,9 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
 {
 	struct pstore_record record;
 
+	if (!c)
+		return;
+
 	pstore_record_init(&record, psinfo);
 	record.type = PSTORE_TYPE_CONSOLE;
 
@@ -493,18 +505,20 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
 }
 
 static struct console pstore_console = {
-	.name	= "pstore",
 	.write	= pstore_console_write,
-#ifdef CON_PSTORE
-	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME | CON_PSTORE,
-#else
-	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
-#endif
 	.index	= -1,
 };
 
 static void pstore_register_console(void)
 {
+	/* Show which backend is going to get console writes. */
+	strscpy(pstore_console.name, psinfo->name,
+		sizeof(pstore_console.name));
+	/*
+	 * Always initialize flags here since prior unregister_console()
+	 * calls may have changed settings (specifically CON_ENABLED).
+	 */
+	pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
 	register_console(&pstore_console);
 }
 
@@ -549,8 +563,6 @@ out:
  */
 int pstore_register(struct pstore_info *psi)
 {
-	struct module *owner = psi->owner;
-
 	if (backend && strcmp(backend, psi->name)) {
 		pr_warn("ignoring unexpected backend '%s'\n", psi->name);
 		return -EPERM;
@@ -570,11 +582,11 @@ int pstore_register(struct pstore_info *psi)
 		return -EINVAL;
 	}
 
-	spin_lock(&pstore_lock);
+	mutex_lock(&psinfo_lock);
 	if (psinfo) {
 		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
 			psinfo->name, psi->name);
-		spin_unlock(&pstore_lock);
+		mutex_unlock(&psinfo_lock);
 		return -EBUSY;
 	}
 
@@ -583,21 +595,16 @@ int pstore_register(struct pstore_info *psi)
 	psinfo = psi;
 	mutex_init(&psinfo->read_mutex);
 	sema_init(&psinfo->buf_lock, 1);
-	spin_unlock(&pstore_lock);
-
-	if (owner && !try_module_get(owner)) {
-		psinfo = NULL;
-		return -EINVAL;
-	}
 
 	if (psi->flags & PSTORE_FLAGS_DMESG)
 		allocate_buf_for_compression();
 
-	if (pstore_is_mounted())
+	pstore_get_records(0);
-		pstore_get_records(0);
 
-	if (psi->flags & PSTORE_FLAGS_DMESG)
+	if (psi->flags & PSTORE_FLAGS_DMESG) {
+		pstore_dumper.max_reason = psinfo->max_reason;
 		pstore_register_kmsg();
+	}
 	if (psi->flags & PSTORE_FLAGS_CONSOLE)
 		pstore_register_console();
 	if (psi->flags & PSTORE_FLAGS_FTRACE)
@@ -606,33 +613,36 @@ int pstore_register(struct pstore_info *psi)
 		pstore_register_pmsg();
 
 	/* Start watching for new records, if desired. */
-	if (pstore_update_ms >= 0) {
+	pstore_timer_kick();
-		pstore_timer.expires = jiffies +
-			msecs_to_jiffies(pstore_update_ms);
-		add_timer(&pstore_timer);
-	}
 
 	/*
 	 * Update the module parameter backend, so it is visible
 	 * through /sys/module/pstore/parameters/backend
 	 */
-	backend = psi->name;
+	backend = kstrdup(psi->name, GFP_KERNEL);
 
 	pr_info("Registered %s as persistent store backend\n", psi->name);
 
-	module_put(owner);
+	mutex_unlock(&psinfo_lock);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_register);
 
 void pstore_unregister(struct pstore_info *psi)
 {
-	/* Stop timer and make sure all work has finished. */
+	/* It's okay to unregister nothing. */
-	pstore_update_ms = -1;
+	if (!psi)
-	del_timer_sync(&pstore_timer);
+		return;
-	flush_work(&pstore_work);
 
+	mutex_lock(&psinfo_lock);
+
+	/* Only one backend can be registered at a time. */
+	if (WARN_ON(psi != psinfo)) {
+		mutex_unlock(&psinfo_lock);
+		return;
+	}
+
+	/* Unregister all callbacks. */
 	if (psi->flags & PSTORE_FLAGS_PMSG)
 		pstore_unregister_pmsg();
 	if (psi->flags & PSTORE_FLAGS_FTRACE)
@@ -642,17 +652,27 @@ void pstore_unregister(struct pstore_info *psi)
 	if (psi->flags & PSTORE_FLAGS_DMESG)
 		pstore_unregister_kmsg();
 
+	/* Stop timer and make sure all work has finished. */
+	del_timer_sync(&pstore_timer);
+	flush_work(&pstore_work);
+
+	/* Remove all backend records from filesystem tree. */
+	pstore_put_backend_records(psi);
+
 	free_buf_for_compression();
 
 	psinfo = NULL;
+	kfree(backend);
 	backend = NULL;
+	mutex_unlock(&psinfo_lock);
 }
 EXPORT_SYMBOL_GPL(pstore_unregister);
 
 static void decompress_record(struct pstore_record *record)
 {
+	int ret;
 	int unzipped_len;
-	char *decompressed;
+	char *unzipped, *workspace;
 
 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
 		return;
@@ -663,35 +683,42 @@ static void decompress_record(struct pstore_record *record)
 		return;
 	}
 
-	/* No compression method has created the common buffer. */
+	/* Missing compression buffer means compression was not initialized. */
 	if (!big_oops_buf) {
-		pr_warn("no decompression buffer allocated\n");
+		pr_warn("no decompression method initialized!\n");
 		return;
 	}
 
-	unzipped_len = pstore_decompress(record->buf, big_oops_buf,
+	/* Allocate enough space to hold max decompression and ECC. */
-					 record->size, big_oops_buf_sz);
+	unzipped_len = big_oops_buf_sz;
-	if (unzipped_len <= 0) {
+	workspace = kmalloc(unzipped_len + record->ecc_notice_size,
-		pr_err("decompression failed: %d\n", unzipped_len);
+			    GFP_KERNEL);
+	if (!workspace)
 		return;
-	}
 
-	/* Build new buffer for decompressed contents. */
+	/* After decompression "unzipped_len" is almost certainly smaller. */
-	decompressed = kmalloc(unzipped_len + record->ecc_notice_size,
+	ret = crypto_comp_decompress(tfm, record->buf, record->size,
-			       GFP_KERNEL);
+					  workspace, &unzipped_len);
-	if (!decompressed) {
+	if (ret) {
-		pr_err("decompression ran out of memory\n");
+		pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
+		kfree(workspace);
 		return;
 	}
-	memcpy(decompressed, big_oops_buf, unzipped_len);
 
 	/* Append ECC notice to decompressed buffer. */
-	memcpy(decompressed + unzipped_len, record->buf + record->size,
+	memcpy(workspace + unzipped_len, record->buf + record->size,
 	       record->ecc_notice_size);
 
-	/* Swap out compresed contents with decompressed contents. */
+	/* Copy decompressed contents into an minimum-sized allocation. */
+	unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
+			   GFP_KERNEL);
+	kfree(workspace);
+	if (!unzipped)
+		return;
+
+	/* Swap out compressed contents with decompressed contents. */
 	kfree(record->buf);
-	record->buf = decompressed;
+	record->buf = unzipped;
 	record->size = unzipped_len;
 	record->compressed = false;
 }
@@ -774,12 +801,10 @@ static void pstore_timefunc(struct timer_list *unused)
 		schedule_work(&pstore_work);
 	}
 
-	if (pstore_update_ms >= 0)
+	pstore_timer_kick();
-		mod_timer(&pstore_timer,
-			  jiffies + msecs_to_jiffies(pstore_update_ms));
 }
 
-void __init pstore_choose_compression(void)
+static void __init pstore_choose_compression(void)
 {
 	const struct pstore_zbackend *step;
 
@@ -821,11 +846,5 @@ static void __exit pstore_exit(void)
 }
 module_exit(pstore_exit)
 
-module_param(compress, charp, 0444);
-MODULE_PARM_DESC(compress, "Pstore compression to use");
-
-module_param(backend, charp, 0444);
-MODULE_PARM_DESC(backend, "Pstore backend to use");
-
 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
 MODULE_LICENSE("GPL");

fs/pstore/pmsg.c

@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2014  Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
  */
 
 #include <linux/cdev.h>
@@ -33,7 +25,7 @@ static ssize_t write_pmsg(struct file *file, const char __user *buf,
 	record.size = count;
 
 	/* check outside lock, page in any data. write_user also checks */
-	if (!access_ok(VERIFY_READ, buf, count))
+	if (!access_ok(buf, count))
 		return -EFAULT;
 
 	mutex_lock(&pmsg_lock);

fs/pstore/ram.c

@@ -1,23 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * RAM Oops/Panic logger
  *
  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
- *
- * 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., 51 Franklin St, Fifth Floor, Boston, MA
- * 02110-1301 USA
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -35,6 +21,12 @@
 #include <linux/pstore_ram.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
+#include "internal.h"
+
+#if IS_REACHABLE(CONFIG_ROCKCHIP_MINIDUMP)
+#include <soc/rockchip/rk_minidump.h>
+#endif
 
 #define RAMOOPS_KERNMSG_HDR "===="
 #define MIN_MEM_SIZE 4096UL
@@ -67,24 +59,63 @@ MODULE_PARM_DESC(mem_size,
 		"size of reserved RAM used to store oops/panic logs");
 
 static unsigned int mem_type;
-module_param(mem_type, uint, 0600);
+module_param(mem_type, uint, 0400);
 MODULE_PARM_DESC(mem_type,
-		"set to 1 to try to use unbuffered memory (default 0)");
+		"memory type: 0=write-combined (default), 1=unbuffered, 2=cached");
 
-static int dump_oops = 1;
+static int ramoops_max_reason = -1;
-module_param(dump_oops, int, 0600);
+module_param_named(max_reason, ramoops_max_reason, int, 0400);
-MODULE_PARM_DESC(dump_oops,
+MODULE_PARM_DESC(max_reason,
-		"set to 1 to dump oopses, 0 to only dump panics (default 1)");
+		 "maximum reason for kmsg dump (default 2: Oops and Panic) ");
 
 static int ramoops_ecc;
-module_param_named(ecc, ramoops_ecc, int, 0600);
+module_param_named(ecc, ramoops_ecc, int, 0400);
 MODULE_PARM_DESC(ramoops_ecc,
 		"if non-zero, the option enables ECC support and specifies "
 		"ECC buffer size in bytes (1 is a special value, means 16 "
 		"bytes ECC)");
 
+static int ramoops_dump_oops = -1;
+module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
+MODULE_PARM_DESC(dump_oops,
+		 "(deprecated: use max_reason instead) set to 1 to dump oopses & panics, 0 to only dump panics");
+
+struct ramoops_context {
+	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
+	struct persistent_ram_zone *cprz;	/* Console zone */
+	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
+	struct persistent_ram_zone *mprz;	/* PMSG zone */
+#ifdef CONFIG_PSTORE_BOOT_LOG
+	struct persistent_ram_zone **boot_przs;	/* BOOT log zones */
+#endif
+	phys_addr_t phys_addr;
+	unsigned long size;
+	unsigned int memtype;
+	size_t record_size;
+	size_t console_size;
+	size_t ftrace_size;
+	size_t pmsg_size;
+#ifdef CONFIG_PSTORE_BOOT_LOG
+	size_t boot_log_size;
+#endif
+	u32 flags;
+	struct persistent_ram_ecc_info ecc_info;
+	unsigned int max_dump_cnt;
+	unsigned int dump_write_cnt;
+	/* _read_cnt need clear on ramoops_pstore_open */
+	unsigned int dump_read_cnt;
+	unsigned int console_read_cnt;
+	unsigned int max_ftrace_cnt;
+	unsigned int ftrace_read_cnt;
+	unsigned int pmsg_read_cnt;
+#ifdef CONFIG_PSTORE_BOOT_LOG
+	unsigned int boot_log_read_cnt;
+	unsigned int max_boot_log_cnt;
+#endif
+	struct pstore_info pstore;
+};
+
 static struct platform_device *dummy;
-static struct ramoops_platform_data *dummy_data;
 
 static int ramoops_pstore_open(struct pstore_info *psi)
 {
@@ -98,31 +129,28 @@ static int ramoops_pstore_open(struct pstore_info *psi)
 }
 
 static struct persistent_ram_zone *
-ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
+ramoops_get_next_prz(struct persistent_ram_zone *przs[], int id,
-		     u64 *id,
+		     struct pstore_record *record)
-		     enum pstore_type_id *typep, enum pstore_type_id type,
-		     bool update)
 {
 	struct persistent_ram_zone *prz;
-	int i = (*c)++;
 
 	/* Give up if we never existed or have hit the end. */
-	if (!przs || i >= max)
+	if (!przs)
 		return NULL;
 
-	prz = przs[i];
+	prz = przs[id];
 	if (!prz)
 		return NULL;
 
 	/* Update old/shadowed buffer. */
-	if (update)
+	if (prz->type == PSTORE_TYPE_DMESG)
 		persistent_ram_save_old(prz);
 
 	if (!persistent_ram_old_size(prz))
 		return NULL;
 
-	*typep = type;
+	record->type = prz->type;
-	*id = i;
+	record->id = id;
 
 	return prz;
 }
@@ -160,57 +188,27 @@ static bool prz_ok(struct persistent_ram_zone *prz)
 			   persistent_ram_ecc_string(prz, NULL, 0));
 }
 
-static ssize_t ftrace_log_combine(struct persistent_ram_zone *dest,
+#ifdef CONFIG_PSTORE_BOOT_LOG
-				  struct persistent_ram_zone *src)
+ssize_t ramoops_pstore_read_for_boot_log(struct pstore_record *record)
 {
-	size_t dest_size, src_size, total, dest_off, src_off;
+	struct ramoops_context *cxt = record->psi->data;
-	size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
+	struct persistent_ram_zone *prz;
-	void *merged_buf;
-	struct pstore_ftrace_record *drec, *srec, *mrec;
-	size_t record_size = sizeof(struct pstore_ftrace_record);
 
-	dest_off = dest->old_log_size % record_size;
+	if (!cxt)
-	dest_size = dest->old_log_size - dest_off;
+		return 0;
 
-	src_off = src->old_log_size % record_size;
+	prz = cxt->boot_przs[record->id];
-	src_size = src->old_log_size - src_off;
 
-	total = dest_size + src_size;
+	if (!prz)
-	merged_buf = kmalloc(total, GFP_KERNEL);
+		return 0;
-	if (!merged_buf)
-		return -ENOMEM;
 
-	drec = (struct pstore_ftrace_record *)(dest->old_log + dest_off);
+	persistent_ram_free_old(prz);
-	srec = (struct pstore_ftrace_record *)(src->old_log + src_off);
+	persistent_ram_save_old(prz);
-	mrec = (struct pstore_ftrace_record *)(merged_buf);
+	record->buf = prz->old_log;
-
+	record->size = prz->old_log_size;
-	while (dest_size > 0 && src_size > 0) {
+	return record->size;
-		if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
-		    pstore_ftrace_read_timestamp(&srec[src_idx])) {
-			mrec[merged_idx++] = drec[dest_idx++];
-			dest_size -= record_size;
-		} else {
-			mrec[merged_idx++] = srec[src_idx++];
-			src_size -= record_size;
-		}
-	}
-
-	while (dest_size > 0) {
-		mrec[merged_idx++] = drec[dest_idx++];
-		dest_size -= record_size;
-	}
-
-	while (src_size > 0) {
-		mrec[merged_idx++] = srec[src_idx++];
-		src_size -= record_size;
-	}
-
-	kfree(dest->old_log);
-	dest->old_log = merged_buf;
-	dest->old_log_size = total;
-
-	return 0;
 }
+#endif
 
 static ssize_t ramoops_pstore_read(struct pstore_record *record)
 {
@@ -231,10 +229,8 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 
 	/* Find the next valid persistent_ram_zone for DMESG */
 	while (cxt->dump_read_cnt < cxt->max_dump_cnt && !prz) {
-		prz = ramoops_get_next_prz(cxt->dprzs, &cxt->dump_read_cnt,
+		prz = ramoops_get_next_prz(cxt->dprzs, cxt->dump_read_cnt++,
-					   cxt->max_dump_cnt, &record->id,
+					   record);
-					   &record->type,
-					   PSTORE_TYPE_DMESG, 1);
 		if (!prz_ok(prz))
 			continue;
 		header_length = ramoops_read_kmsg_hdr(persistent_ram_old(prz),
@@ -248,22 +244,18 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 		}
 	}
 
-	if (!prz_ok(prz))
+	if (!prz_ok(prz) && !cxt->console_read_cnt++)
-		prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt,
+		prz = ramoops_get_next_prz(&cxt->cprz, 0 /* single */, record);
-					   1, &record->id, &record->type,
-					   PSTORE_TYPE_CONSOLE, 0);
 
-	if (!prz_ok(prz))
+	if (!prz_ok(prz) && !cxt->pmsg_read_cnt++)
-		prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt,
+		prz = ramoops_get_next_prz(&cxt->mprz, 0 /* single */, record);
-					   1, &record->id, &record->type,
-					   PSTORE_TYPE_PMSG, 0);
 
 	/* ftrace is last since it may want to dynamically allocate memory. */
 	if (!prz_ok(prz)) {
-		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
+		if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) &&
-			prz = ramoops_get_next_prz(cxt->fprzs,
+		    !cxt->ftrace_read_cnt++) {
-					&cxt->ftrace_read_cnt, 1, &record->id,
+			prz = ramoops_get_next_prz(cxt->fprzs, 0 /* single */,
-					&record->type, PSTORE_TYPE_FTRACE, 0);
+						   record);
 		} else {
 			/*
 			 * Build a new dummy record which combines all the
@@ -280,11 +272,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 
 			while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt) {
 				prz_next = ramoops_get_next_prz(cxt->fprzs,
-						&cxt->ftrace_read_cnt,
+						cxt->ftrace_read_cnt++, record);
-						cxt->max_ftrace_cnt,
-						&record->id,
-						&record->type,
-						PSTORE_TYPE_FTRACE, 0);
 
 				if (!prz_ok(prz_next))
 					continue;
@@ -293,7 +281,12 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 				tmp_prz->corrected_bytes +=
 						prz_next->corrected_bytes;
 				tmp_prz->bad_blocks += prz_next->bad_blocks;
-				size = ftrace_log_combine(tmp_prz, prz_next);
+
+				size = pstore_ftrace_combine_log(
+						&tmp_prz->old_log,
+						&tmp_prz->old_log_size,
+						prz_next->old_log,
+						prz_next->old_log_size);
 				if (size)
 					goto out;
 			}
@@ -304,10 +297,7 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 #ifdef CONFIG_PSTORE_BOOT_LOG
 	if (!prz_ok(prz)) {
 		while (cxt->boot_log_read_cnt < cxt->max_boot_log_cnt && !prz) {
-			prz = ramoops_get_next_prz(cxt->boot_przs, &cxt->boot_log_read_cnt,
+			prz = ramoops_get_next_prz(cxt->boot_przs, cxt->boot_log_read_cnt++, record);
-						cxt->max_boot_log_cnt, &record->id,
-						&record->type,
-						PSTORE_TYPE_BOOT_LOG, 0);
 			if (!prz_ok(prz))
 				continue;
 		}
@@ -319,12 +309,15 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
 		goto out;
 	}
 
-	size = persistent_ram_old_size(prz) - header_length;
 #ifdef CONFIG_PSTORE_BOOT_LOG
-	/* don't copy boot log */
+	if (record->type == PSTORE_TYPE_BOOT_LOG) {
-	if (record->type == PSTORE_TYPE_BOOT_LOG)
+		persistent_ram_free_old(prz);
-		goto out;
+		persistent_ram_save_old(prz);
+	}
 #endif
+
+	size = persistent_ram_old_size(prz) - header_length;
+
 	/* ECC correction notice */
 	record->ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
 
@@ -352,17 +345,15 @@ out:
 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
 				     struct pstore_record *record)
 {
-	char *hdr;
+	char hdr[36]; /* "===="(4), %lld(20), "."(1), %06lu(6), "-%c\n"(3) */
 	size_t len;
 
-	hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
+	len = scnprintf(hdr, sizeof(hdr),
+		RAMOOPS_KERNMSG_HDR "%lld.%06lu-%c\n",
 		(time64_t)record->time.tv_sec,
 		record->time.tv_nsec / 1000,
 		record->compressed ? 'C' : 'D');
-	WARN_ON_ONCE(!hdr);
-	len = hdr ? strlen(hdr) : 0;
 	persistent_ram_write(prz, hdr, len);
-	kfree(hdr);
 
 	return len;
 }
@@ -403,16 +394,14 @@ static int notrace ramoops_pstore_write(struct pstore_record *record)
 		return -EINVAL;
 
 	/*
-	 * Out of the various dmesg dump types, ramoops is currently designed
+	 * We could filter on record->reason here if we wanted to (which
-	 * to only store crash logs, rather than storing general kernel logs.
+	 * would duplicate what happened before the "max_reason" setting
+	 * was added), but that would defeat the purpose of a system
+	 * changing printk.always_kmsg_dump, so instead log everything that
+	 * the kmsg dumper sends us, since it should be doing the filtering
+	 * based on the combination of printk.always_kmsg_dump and our
+	 * requested "max_reason".
 	 */
-	if (record->reason != KMSG_DUMP_OOPS &&
-	    record->reason != KMSG_DUMP_PANIC)
-		return -EINVAL;
-
-	/* Skip Oopes when configured to do so. */
-	if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops)
-		return -EINVAL;
 
 	/*
 	 * Explicitly only take the first part of any new crash.
@@ -441,6 +430,9 @@ static int notrace ramoops_pstore_write(struct pstore_record *record)
 
 	/* Build header and append record contents. */
 	hlen = ramoops_write_kmsg_hdr(prz, record);
+	if (!hlen)
+		return -ENOMEM;
+
 	size = record->size;
 	if (size + hlen > prz->buffer_size)
 		size = prz->buffer_size - hlen;
@@ -600,9 +592,17 @@ static int ramoops_init_przs(const char *name,
 		goto fail;
 
 	for (i = 0; i < *cnt; i++) {
+		char *label;
+
+		if (*cnt == 1)
+			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
+		else
+			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
+					  name, i, *cnt - 1);
 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
-						  &cxt->ecc_info,
+					       &cxt->ecc_info,
-						  cxt->memtype, flags);
+					       cxt->memtype, flags, label);
+		kfree(label);
 		if (IS_ERR(prz_ar[i])) {
 			err = PTR_ERR(prz_ar[i]);
 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
@@ -617,6 +617,7 @@ static int ramoops_init_przs(const char *name,
 			goto fail;
 		}
 		*paddr += zone_sz;
+		prz_ar[i]->type = pstore_name_to_type(name);
 	}
 
 	*przs = prz_ar;
@@ -632,6 +633,8 @@ static int ramoops_init_prz(const char *name,
 			    struct persistent_ram_zone **prz,
 			    phys_addr_t *paddr, size_t sz, u32 sig)
 {
+	char *label;
+
 	if (!sz)
 		return 0;
 
@@ -642,8 +645,10 @@ static int ramoops_init_prz(const char *name,
 		return -ENOMEM;
 	}
 
+	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
-				  cxt->memtype, 0);
+				  cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
+	kfree(label);
 	if (IS_ERR(*prz)) {
 		int err = PTR_ERR(*prz);
 
@@ -652,26 +657,31 @@ static int ramoops_init_prz(const char *name,
 		return err;
 	}
 
-	persistent_ram_zap(*prz);
-
 	*paddr += sz;
+	(*prz)->type = pstore_name_to_type(name);
 
 	return 0;
 }
 
-static int ramoops_parse_dt_size(struct platform_device *pdev,
+/* Read a u32 from a dt property and make sure it's safe for an int. */
-				 const char *propname, u32 *value)
+static int ramoops_parse_dt_u32(struct platform_device *pdev,
+				const char *propname,
+				u32 default_value, u32 *value)
 {
 	u32 val32 = 0;
 	int ret;
 
 	ret = of_property_read_u32(pdev->dev.of_node, propname, &val32);
-	if (ret < 0 && ret != -EINVAL) {
+	if (ret == -EINVAL) {
+		/* field is missing, use default value. */
+		val32 = default_value;
+	} else if (ret < 0) {
 		dev_err(&pdev->dev, "failed to parse property %s: %d\n",
 			propname, ret);
 		return ret;
 	}
 
+	/* Sanity check our results. */
 	if (val32 > INT_MAX) {
 		dev_err(&pdev->dev, "%s %u > INT_MAX\n", propname, val32);
 		return -EOVERFLOW;
@@ -685,6 +695,8 @@ static int ramoops_parse_dt(struct platform_device *pdev,
 			    struct ramoops_platform_data *pdata)
 {
 	struct device_node *of_node = pdev->dev.of_node;
+	struct device_node *parent_node;
+	struct reserved_mem *rmem;
 	struct resource *res;
 	u32 value;
 	int ret;
@@ -693,38 +705,123 @@ static int ramoops_parse_dt(struct platform_device *pdev,
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
-		dev_err(&pdev->dev,
+		rmem = of_reserved_mem_lookup(of_node);
-			"failed to locate DT /reserved-memory resource\n");
+		if (rmem) {
-		return -EINVAL;
+			pdata->mem_size = rmem->size;
+			pdata->mem_address = rmem->base;
+		} else {
+			dev_err(&pdev->dev,
+				"failed to locate DT /reserved-memory resource\n");
+			return -EINVAL;
+		}
+	} else {
+		pdata->mem_size = resource_size(res);
+		pdata->mem_address = res->start;
 	}
 
-	pdata->mem_size = resource_size(res);
+	/*
-	pdata->mem_address = res->start;
+	 * Setting "unbuffered" is deprecated and will be ignored if
+	 * "mem_type" is also specified.
+	 */
 	pdata->mem_type = of_property_read_bool(of_node, "unbuffered");
-	pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops");
+	/*
+	 * Setting "no-dump-oops" is deprecated and will be ignored if
+	 * "max_reason" is also specified.
+	 */
+	if (of_property_read_bool(of_node, "no-dump-oops"))
+		pdata->max_reason = KMSG_DUMP_PANIC;
+	else
+		pdata->max_reason = KMSG_DUMP_OOPS;
 
-#define parse_size(name, field) {					\
+#define parse_u32(name, field, default_value) {				\
-		ret = ramoops_parse_dt_size(pdev, name, &value);	\
+		ret = ramoops_parse_dt_u32(pdev, name, default_value,	\
+					    &value);			\
 		if (ret < 0)						\
 			return ret;					\
 		field = value;						\
 	}
 
-	parse_size("record-size", pdata->record_size);
+	parse_u32("mem-type", pdata->mem_type, pdata->mem_type);
-	parse_size("console-size", pdata->console_size);
+	parse_u32("record-size", pdata->record_size, 0);
-	parse_size("ftrace-size", pdata->ftrace_size);
+	parse_u32("console-size", pdata->console_size, 0);
-	parse_size("pmsg-size", pdata->pmsg_size);
+	parse_u32("ftrace-size", pdata->ftrace_size, 0);
-	parse_size("ecc-size", pdata->ecc_info.ecc_size);
+	parse_u32("pmsg-size", pdata->pmsg_size, 0);
-	parse_size("flags", pdata->flags);
+	parse_u32("ecc-size", pdata->ecc_info.ecc_size, 0);
+	parse_u32("flags", pdata->flags, 0);
+	parse_u32("max-reason", pdata->max_reason, pdata->max_reason);
 #ifdef CONFIG_PSTORE_BOOT_LOG
-	parse_size("boot-log-size", pdata->boot_log_size);
+	parse_u32("boot-log-size", pdata->boot_log_size, 0);
-	parse_size("boot-log-count", pdata->max_boot_log_cnt);
+	parse_u32("boot-log-count", pdata->max_boot_log_cnt, 0);
 #endif
-#undef parse_size
+
+#undef parse_u32
+
+	/*
+	 * Some old Chromebooks relied on the kernel setting the
+	 * console_size and pmsg_size to the record size since that's
+	 * what the downstream kernel did.  These same Chromebooks had
+	 * "ramoops" straight under the root node which isn't
+	 * according to the current upstream bindings (though it was
+	 * arguably acceptable under a prior version of the bindings).
+	 * Let's make those old Chromebooks work by detecting that
+	 * we're not a child of "reserved-memory" and mimicking the
+	 * expected behavior.
+	 */
+	parent_node = of_get_parent(of_node);
+	if (!of_node_name_eq(parent_node, "reserved-memory") &&
+	    !pdata->console_size && !pdata->ftrace_size &&
+	    !pdata->pmsg_size && !pdata->ecc_info.ecc_size) {
+		pdata->console_size = pdata->record_size;
+		pdata->pmsg_size = pdata->record_size;
+	}
+	of_node_put(parent_node);
 
 	return 0;
 }
 
+#if IS_REACHABLE(CONFIG_ROCKCHIP_MINIDUMP)
+static void _ramoops_register_ram_zone_info_to_minidump(struct persistent_ram_zone *prz)
+{
+	struct md_region md_entry = {};
+
+	strscpy(md_entry.name, prz->label, sizeof(md_entry.name));
+
+	md_entry.virt_addr = (u64)prz->vaddr;
+	md_entry.phys_addr = prz->paddr;
+	md_entry.size = prz->size;
+
+	if (rk_minidump_add_region(&md_entry) < 0)
+		pr_err("Failed to add %s in Minidump\n", prz->label);
+}
+
+static void ramoops_register_ram_zone_info_to_minidump(struct ramoops_context *cxt)
+{
+	int i = 0;
+	struct persistent_ram_zone *prz = NULL;
+
+	for (i = 0; i < cxt->max_boot_log_cnt; i++) {
+		prz = cxt->boot_przs[i];
+		_ramoops_register_ram_zone_info_to_minidump(prz);
+	}
+
+	for (i = 0; i < cxt->max_dump_cnt; i++) {
+		prz = cxt->dprzs[i];
+		_ramoops_register_ram_zone_info_to_minidump(prz);
+	}
+
+	for (i = 0; i < cxt->max_ftrace_cnt; i++) {
+		prz = cxt->fprzs[i];
+		_ramoops_register_ram_zone_info_to_minidump(prz);
+	}
+
+	prz = cxt->cprz;
+	_ramoops_register_ram_zone_info_to_minidump(prz);
+
+	prz = cxt->mprz;
+	_ramoops_register_ram_zone_info_to_minidump(prz);
+}
+#endif
+
 static int ramoops_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -736,15 +833,6 @@ static int ramoops_probe(struct platform_device *pdev)
 	int err = -EINVAL;
 	int i = 0;
 
-	if (dev_of_node(dev) && !pdata) {
-		pdata = &pdata_local;
-		memset(pdata, 0, sizeof(*pdata));
-
-		err = ramoops_parse_dt(pdev, pdata);
-		if (err < 0)
-			goto fail_out;
-	}
-
 	/*
 	 * Only a single ramoops area allowed at a time, so fail extra
 	 * probes.
@@ -754,6 +842,15 @@ static int ramoops_probe(struct platform_device *pdev)
 		goto fail_out;
 	}
 
+	if (dev_of_node(dev) && !pdata) {
+		pdata = &pdata_local;
+		memset(pdata, 0, sizeof(*pdata));
+
+		err = ramoops_parse_dt(pdev, pdata);
+		if (err < 0)
+			goto fail_out;
+	}
+
 	/* Make sure we didn't get bogus platform data pointer. */
 	if (!pdata) {
 		pr_err("NULL platform data\n");
@@ -794,7 +891,6 @@ static int ramoops_probe(struct platform_device *pdev)
 	cxt->console_size = pdata->console_size;
 	cxt->ftrace_size = pdata->ftrace_size;
 	cxt->pmsg_size = pdata->pmsg_size;
-	cxt->dump_oops = pdata->dump_oops;
 	cxt->flags = pdata->flags;
 	cxt->ecc_info = pdata->ecc_info;
 #ifdef CONFIG_PSTORE_BOOT_LOG
@@ -811,7 +907,7 @@ static int ramoops_probe(struct platform_device *pdev)
 #endif
 
 #ifdef CONFIG_PSTORE_BOOT_LOG
-	err = ramoops_init_przs("boot_log", dev, cxt, &cxt->boot_przs, &paddr,
+	err = ramoops_init_przs("boot-log", dev, cxt, &cxt->boot_przs, &paddr,
 				cxt->boot_log_size, -1,
 				&cxt->max_boot_log_cnt, 0, 0);
 	if (err)
@@ -821,7 +917,7 @@ static int ramoops_probe(struct platform_device *pdev)
 			pr_info("boot-log-%d\t0x%zx@%pa\n", i, cxt->boot_przs[i]->size, &cxt->boot_przs[i]->paddr);
 #endif
 
-	err = ramoops_init_przs("dump", dev, cxt, &cxt->dprzs, &paddr,
+	err = ramoops_init_przs("dmesg", dev, cxt, &cxt->dprzs, &paddr,
 				dump_mem_sz, cxt->record_size,
 				&cxt->max_dump_cnt, 0, 0);
 	if (err)
@@ -855,7 +951,6 @@ static int ramoops_probe(struct platform_device *pdev)
 				cxt->pmsg_size, 0);
 	if (err)
 		goto fail_init_mprz;
-
 	if (cxt->pmsg_size > 0)
 		pr_info("pmsg\t0x%zx@%pa\n", cxt->mprz->size, &cxt->mprz->paddr);
 
@@ -867,8 +962,10 @@ static int ramoops_probe(struct platform_device *pdev)
 	 * the single region size is how to check.
 	 */
 	cxt->pstore.flags = 0;
-	if (cxt->max_dump_cnt)
+	if (cxt->max_dump_cnt) {
 		cxt->pstore.flags |= PSTORE_FLAGS_DMESG;
+		cxt->pstore.max_reason = pdata->max_reason;
+	}
 	if (cxt->console_size)
 		cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE;
 	if (cxt->max_ftrace_cnt)
@@ -908,14 +1005,16 @@ static int ramoops_probe(struct platform_device *pdev)
 	mem_size = pdata->mem_size;
 	mem_address = pdata->mem_address;
 	record_size = pdata->record_size;
-	dump_oops = pdata->dump_oops;
+	ramoops_max_reason = pdata->max_reason;
 	ramoops_console_size = pdata->console_size;
 	ramoops_pmsg_size = pdata->pmsg_size;
 	ramoops_ftrace_size = pdata->ftrace_size;
-
+#if IS_REACHABLE(CONFIG_ROCKCHIP_MINIDUMP)
-	pr_info("attached 0x%lx@0x%llx, ecc: %d/%d\n",
+	ramoops_register_ram_zone_info_to_minidump(cxt);
+#endif
+	pr_info("using 0x%lx@0x%llx, ecc: %d\n",
 		cxt->size, (unsigned long long)cxt->phys_addr,
-		cxt->ecc_info.ecc_size, cxt->ecc_info.block_size);
+		cxt->ecc_info.ecc_size);
 
 	return 0;
 
@@ -967,13 +1066,12 @@ static inline void ramoops_unregister_dummy(void)
 {
 	platform_device_unregister(dummy);
 	dummy = NULL;
-
-	kfree(dummy_data);
-	dummy_data = NULL;
 }
 
 static void __init ramoops_register_dummy(void)
 {
+	struct ramoops_platform_data pdata;
+
 	/*
 	 * Prepare a dummy platform data structure to carry the module
 	 * parameters. If mem_size isn't set, then there are no module
@@ -984,35 +1082,38 @@ static void __init ramoops_register_dummy(void)
 
 	pr_info("using module parameters\n");
 
-	dummy_data = kzalloc(sizeof(*dummy_data), GFP_KERNEL);
+	memset(&pdata, 0, sizeof(pdata));
-	if (!dummy_data) {
+	pdata.mem_size = mem_size;
-		pr_info("could not allocate pdata\n");
+	pdata.mem_address = mem_address;
-		return;
+	pdata.mem_type = mem_type;
-	}
+	pdata.record_size = record_size;
-
+	pdata.console_size = ramoops_console_size;
-	dummy_data->mem_size = mem_size;
+	pdata.ftrace_size = ramoops_ftrace_size;
-	dummy_data->mem_address = mem_address;
+	pdata.pmsg_size = ramoops_pmsg_size;
-	dummy_data->mem_type = mem_type;
+	/* If "max_reason" is set, its value has priority over "dump_oops". */
-	dummy_data->record_size = record_size;
+	if (ramoops_max_reason >= 0)
-	dummy_data->console_size = ramoops_console_size;
+		pdata.max_reason = ramoops_max_reason;
-	dummy_data->ftrace_size = ramoops_ftrace_size;
+	/* Otherwise, if "dump_oops" is set, parse it into "max_reason". */
-	dummy_data->pmsg_size = ramoops_pmsg_size;
+	else if (ramoops_dump_oops != -1)
-	dummy_data->dump_oops = dump_oops;
+		pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS
-	dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
+						     : KMSG_DUMP_PANIC;
+	/* And if neither are explicitly set, use the default. */
+	else
+		pdata.max_reason = KMSG_DUMP_OOPS;
+	pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU;
 
 	/*
 	 * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC
 	 * (using 1 byte for ECC isn't much of use anyway).
 	 */
-	dummy_data->ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
+	pdata.ecc_info.ecc_size = ramoops_ecc == 1 ? 16 : ramoops_ecc;
 
 	dummy = platform_device_register_data(NULL, "ramoops", -1,
-			dummy_data, sizeof(struct ramoops_platform_data));
+			&pdata, sizeof(pdata));
 	if (IS_ERR(dummy)) {
 		pr_info("could not create platform device: %ld\n",
 			PTR_ERR(dummy));
 		dummy = NULL;
-		ramoops_unregister_dummy();
 	}
 }
 

fs/pstore/ram_core.c

@@ -1,18 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
- *
  */
 
-#define pr_fmt(fmt) "persistent_ram: " fmt
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/device.h>
 #include <linux/err.h>
@@ -29,6 +20,23 @@
 #include <linux/vmalloc.h>
 #include <asm/page.h>
 
+/**
+ * struct persistent_ram_buffer - persistent circular RAM buffer
+ *
+ * @sig:
+ *	signature to indicate header (PERSISTENT_RAM_SIG xor PRZ-type value)
+ * @start:
+ *	offset into @data where the beginning of the stored bytes begin
+ * @size:
+ *	number of valid bytes stored in @data
+ */
+struct persistent_ram_buffer {
+	uint32_t    sig;
+	atomic_t    start;
+	atomic_t    size;
+	uint8_t     data[];
+};
+
 #define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
 
 static inline size_t buffer_size(struct persistent_ram_zone *prz)
@@ -275,7 +283,7 @@ static int notrace persistent_ram_update_user(struct persistent_ram_zone *prz,
 	const void __user *s, unsigned int start, unsigned int count)
 {
 	struct persistent_ram_buffer *buffer = prz->buffer;
-	int ret = unlikely(__copy_from_user(buffer->data + start, s, count)) ?
+	int ret = unlikely(copy_from_user(buffer->data + start, s, count)) ?
 		-EFAULT : 0;
 	persistent_ram_update_ecc(prz, start, count);
 	return ret;
@@ -340,8 +348,6 @@ int notrace persistent_ram_write_user(struct persistent_ram_zone *prz,
 	int rem, ret = 0, c = count;
 	size_t start;
 
-	if (unlikely(!access_ok(VERIFY_READ, s, count)))
-		return -EFAULT;
 	if (unlikely(c > prz->buffer_size)) {
 		s += c - prz->buffer_size;
 		c = prz->buffer_size;
@@ -390,6 +396,10 @@ void persistent_ram_zap(struct persistent_ram_zone *prz)
 	persistent_ram_update_header_ecc(prz);
 }
 
+#define MEM_TYPE_WCOMBINE	0
+#define MEM_TYPE_NONCACHED	1
+#define MEM_TYPE_NORMAL		2
+
 static void *persistent_ram_vmap(phys_addr_t start, size_t size,
 		unsigned int memtype)
 {
@@ -403,10 +413,20 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size,
 	page_start = start - offset_in_page(start);
 	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
 
-	if (memtype)
+	switch (memtype) {
+	case MEM_TYPE_NORMAL:
+		prot = PAGE_KERNEL;
+		break;
+	case MEM_TYPE_NONCACHED:
 		prot = pgprot_noncached(PAGE_KERNEL);
-	else
+		break;
+	case MEM_TYPE_WCOMBINE:
 		prot = pgprot_writecombine(PAGE_KERNEL);
+		break;
+	default:
+		pr_err("invalid mem_type=%d\n", memtype);
+		return NULL;
+	}
 
 	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
 	if (!pages) {
@@ -431,12 +451,13 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size,
 }
 
 static void *persistent_ram_iomap(phys_addr_t start, size_t size,
-		unsigned int memtype)
+		unsigned int memtype, char *label)
 {
 	void *va;
 
-	if (!request_mem_region(start, size, "persistent_ram")) {
+	if (!request_mem_region(start, size, label ?: "ramoops")) {
-		pr_err("request mem region (0x%llx@0x%llx) failed\n",
+		pr_err("request mem region (%s 0x%llx@0x%llx) failed\n",
+			label ?: "ramoops",
 			(unsigned long long)size, (unsigned long long)start);
 		return NULL;
 	}
@@ -463,7 +484,8 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 	if (pfn_valid(start >> PAGE_SHIFT))
 		prz->vaddr = persistent_ram_vmap(start, size, memtype);
 	else
-		prz->vaddr = persistent_ram_iomap(start, size, memtype);
+		prz->vaddr = persistent_ram_iomap(start, size, memtype,
+						  prz->label);
 
 	if (!prz->vaddr) {
 		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
@@ -481,10 +503,13 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
 				    struct persistent_ram_ecc_info *ecc_info)
 {
 	int ret;
+	bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD);
 
 	ret = persistent_ram_init_ecc(prz, ecc_info);
-	if (ret)
+	if (ret) {
+		pr_warn("ECC failed %s\n", prz->label);
 		return ret;
+	}
 
 	sig ^= PERSISTENT_RAM_SIG;
 
@@ -495,23 +520,25 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
 		}
 
 		if (buffer_size(prz) > prz->buffer_size ||
-		    buffer_start(prz) > buffer_size(prz))
+		    buffer_start(prz) > buffer_size(prz)) {
 			pr_info("found existing invalid buffer, size %zu, start %zu\n",
 				buffer_size(prz), buffer_start(prz));
-		else {
+			zap = true;
+		} else {
 			pr_debug("found existing buffer, size %zu, start %zu\n",
 				 buffer_size(prz), buffer_start(prz));
 			persistent_ram_save_old(prz);
-			return 0;
 		}
 	} else {
 		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
 			 prz->buffer->sig);
+		prz->buffer->sig = sig;
+		zap = true;
 	}
 
-	/* Rewind missing or invalid memory area. */
+	/* Reset missing, invalid, or single-use memory area. */
-	prz->buffer->sig = sig;
+	if (zap)
-	persistent_ram_zap(prz);
+		persistent_ram_zap(prz);
 
 	return 0;
 }
@@ -539,12 +566,13 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 	prz->ecc_info.par = NULL;
 
 	persistent_ram_free_old(prz);
+	kfree(prz->label);
 	kfree(prz);
 }
 
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
-			unsigned int memtype, u32 flags)
+			unsigned int memtype, u32 flags, char *label)
 {
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;
@@ -558,6 +586,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 	/* Initialize general buffer state. */
 	raw_spin_lock_init(&prz->buffer_lock);
 	prz->flags = flags;
+	prz->label = kstrdup(label, GFP_KERNEL);
 
 	ret = persistent_ram_buffer_map(start, size, prz, memtype);
 	if (ret)
@@ -567,6 +596,12 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 	if (ret)
 		goto err;
 
+	pr_debug("attached %s 0x%zx@0x%llx: %zu header, %zu data, %zu ecc (%d/%d)\n",
+		prz->label, prz->size, (unsigned long long)prz->paddr,
+		sizeof(*prz->buffer), prz->buffer_size,
+		prz->size - sizeof(*prz->buffer) - prz->buffer_size,
+		prz->ecc_info.ecc_size, prz->ecc_info.block_size);
+
 	return prz;
 err:
 	persistent_ram_free(prz);

include/linux/kmsg_dump.h

@@ -28,6 +28,7 @@ enum kmsg_dump_reason {
 	KMSG_DUMP_RESTART,
 	KMSG_DUMP_HALT,
 	KMSG_DUMP_POWEROFF,
+	KMSG_DUMP_SHUTDOWN = KMSG_DUMP_POWEROFF,
 };
 
 /**
@@ -54,7 +55,7 @@ struct kmsg_dumper {
 
 #ifdef CONFIG_PRINTK
 void kmsg_dump(enum kmsg_dump_reason reason);
-
+const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason);
 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
 			       char *line, size_t size, size_t *len);
 

include/linux/pstore.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Persistent Storage - pstore.h
  *
@@ -5,19 +6,6 @@
  *
  * This code is the generic layer to export data records from platform
  * level persistent storage via a file system.
- *
- *  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
  */
 #ifndef _LINUX_PSTORE_H
 #define _LINUX_PSTORE_H
@@ -32,13 +20,19 @@
 
 struct module;
 
-/* pstore record types (see fs/pstore/inode.c for filename templates) */
+/*
+ * pstore record types (see fs/pstore/platform.c for pstore_type_names[])
+ * These values may be written to storage (see EFI vars backend), so
+ * they are kind of an ABI. Be careful changing the mappings.
+ */
 enum pstore_type_id {
+	/* Frontend storage types */
 	PSTORE_TYPE_DMESG	= 0,
 	PSTORE_TYPE_MCE		= 1,
 	PSTORE_TYPE_CONSOLE	= 2,
 	PSTORE_TYPE_FTRACE	= 3,
-	/* PPC64 partition types */
+
+	/* PPC64-specific partition types */
 	PSTORE_TYPE_PPC_RTAS	= 4,
 	PSTORE_TYPE_PPC_OF	= 5,
 	PSTORE_TYPE_PPC_COMMON	= 6,
@@ -47,9 +41,14 @@ enum pstore_type_id {
 #ifdef CONFIG_PSTORE_BOOT_LOG
 	PSTORE_TYPE_BOOT_LOG	= 9,
 #endif
-	PSTORE_TYPE_UNKNOWN	= 255
+
+	/* End of the list */
+	PSTORE_TYPE_MAX
 };
 
+const char *pstore_type_to_name(enum pstore_type_id type);
+enum pstore_type_id pstore_name_to_type(const char *name);
+
 struct pstore_info;
 /**
  * struct pstore_record - details of a pstore record entry
@@ -88,7 +87,7 @@ struct pstore_record {
 /**
  * struct pstore_info - backend pstore driver structure
  *
- * @owner:	module which is repsonsible for this backend driver
+ * @owner:	module which is responsible for this backend driver
  * @name:	name of the backend driver
  *
  * @buf_lock:	semaphore to serialize access to @buf
@@ -100,6 +99,12 @@ struct pstore_record {
  *
  * @read_mutex:	serializes @open, @read, @close, and @erase callbacks
  * @flags:	bitfield of frontends the backend can accept writes for
+ * @max_reason:	Used when PSTORE_FLAGS_DMESG is set. Contains the
+ *		kmsg_dump_reason enum value. KMSG_DUMP_UNDEF means
+ *		"use existing kmsg_dump() filtering, based on the
+ *		printk.always_kmsg_dump boot param" (which is either
+ *		KMSG_DUMP_OOPS when false, or KMSG_DUMP_MAX when
+ *		true); see printk.always_kmsg_dump for more details.
  * @data:	backend-private pointer passed back during callbacks
  *
  * Callbacks:
@@ -174,7 +179,7 @@ struct pstore_record {
  */
 struct pstore_info {
 	struct module	*owner;
-	char		*name;
+	const char	*name;
 
 	struct semaphore buf_lock;
 	char		*buf;
@@ -183,6 +188,7 @@ struct pstore_info {
 	struct mutex	read_mutex;
 
 	int		flags;
+	int		max_reason;
 	void		*data;
 
 	int		(*open)(struct pstore_info *psi);
@@ -195,13 +201,14 @@ struct pstore_info {
 };
 
 /* Supported frontends */
-#define PSTORE_FLAGS_DMESG	(1 << 0)
+#define PSTORE_FLAGS_DMESG	BIT(0)
-#define PSTORE_FLAGS_CONSOLE	(1 << 1)
+#define PSTORE_FLAGS_CONSOLE	BIT(1)
-#define PSTORE_FLAGS_FTRACE	(1 << 2)
+#define PSTORE_FLAGS_FTRACE	BIT(2)
-#define PSTORE_FLAGS_PMSG	(1 << 3)
+#define PSTORE_FLAGS_PMSG	BIT(3)
 #ifdef CONFIG_PSTORE_BOOT_LOG
-#define PSTORE_FLAGS_BOOT_LOG	(1 << 4)
+#define PSTORE_FLAGS_BOOT_LOG	BIT(4)
 #endif
+
 extern int pstore_register(struct pstore_info *);
 extern void pstore_unregister(struct pstore_info *);
 

include/linux/pstore_ram.h

@@ -1,17 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
  * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
  * Copyright (C) 2011 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * 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.
- *
  */
 
 #ifndef __LINUX_PSTORE_RAM_H__
@@ -22,8 +13,8 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
-#include <linux/types.h>
 #include <linux/pstore.h>
+#include <linux/types.h>
 
 /*
  * Choose whether access to the RAM zone requires locking or not.  If a zone
@@ -31,17 +22,15 @@
  * PRZ_FLAG_NO_LOCK is used. For all other cases, locking is required.
  */
 #define PRZ_FLAG_NO_LOCK	BIT(0)
+/*
+ * If a PRZ should only have a single-boot lifetime, this marks it as
+ * getting wiped after its contents get copied out after boot.
+ */
+#define PRZ_FLAG_ZAP_OLD	BIT(1)
 
 struct persistent_ram_buffer;
 struct rs_control;
 
-struct persistent_ram_buffer {
-	uint32_t    sig;
-	atomic_t    start;
-	atomic_t    size;
-	uint8_t     data[0];
-};
-
 struct persistent_ram_ecc_info {
 	int block_size;
 	int ecc_size;
@@ -50,16 +39,55 @@ struct persistent_ram_ecc_info {
 	uint16_t *par;
 };
 
+/**
+ * struct persistent_ram_zone - Details of a persistent RAM zone (PRZ)
+ *                              used as a pstore backend
+ *
+ * @paddr:	physical address of the mapped RAM area
+ * @size:	size of mapping
+ * @label:	unique name of this PRZ
+ * @type:	frontend type for this PRZ
+ * @flags:	holds PRZ_FLAGS_* bits
+ *
+ * @buffer_lock:
+ *	locks access to @buffer "size" bytes and "start" offset
+ * @buffer:
+ *	pointer to actual RAM area managed by this PRZ
+ * @buffer_size:
+ *	bytes in @buffer->data (not including any trailing ECC bytes)
+ *
+ * @par_buffer:
+ *	pointer into @buffer->data containing ECC bytes for @buffer->data
+ * @par_header:
+ *	pointer into @buffer->data containing ECC bytes for @buffer header
+ *	(i.e. all fields up to @data)
+ * @rs_decoder:
+ *	RSLIB instance for doing ECC calculations
+ * @corrected_bytes:
+ *	ECC corrected bytes accounting since boot
+ * @bad_blocks:
+ *	ECC uncorrectable bytes accounting since boot
+ * @ecc_info:
+ *	ECC configuration details
+ *
+ * @old_log:
+ *	saved copy of @buffer->data prior to most recent wipe
+ * @old_log_size:
+ *	bytes contained in @old_log
+ *
+ */
 struct persistent_ram_zone {
 	phys_addr_t paddr;
 	size_t size;
 	void *vaddr;
+	char *label;
+	enum pstore_type_id type;
+	u32 flags;
+
+	raw_spinlock_t buffer_lock;
 	struct persistent_ram_buffer *buffer;
 	size_t buffer_size;
-	u32 flags;
-	raw_spinlock_t buffer_lock;
 
-	/* ECC correction */
 	char *par_buffer;
 	char *par_header;
 	struct rs_control *rs_decoder;
@@ -71,45 +99,9 @@ struct persistent_ram_zone {
 	size_t old_log_size;
 };
 
-struct ramoops_context {
-	struct persistent_ram_zone **dprzs;	/* Oops dump zones */
-	struct persistent_ram_zone *cprz;	/* Console zone */
-	struct persistent_ram_zone **fprzs;	/* Ftrace zones */
-	struct persistent_ram_zone *mprz;	/* PMSG zone */
-#ifdef CONFIG_PSTORE_BOOT_LOG
-	struct persistent_ram_zone **boot_przs;	/* BOOT log zones */
-#endif
-	phys_addr_t phys_addr;
-	unsigned long size;
-	unsigned int memtype;
-	size_t record_size;
-	size_t console_size;
-	size_t ftrace_size;
-	size_t pmsg_size;
-#ifdef CONFIG_PSTORE_BOOT_LOG
-	size_t boot_log_size;
-#endif
-	int dump_oops;
-	u32 flags;
-	struct persistent_ram_ecc_info ecc_info;
-	unsigned int max_dump_cnt;
-	unsigned int dump_write_cnt;
-	/* _read_cnt need clear on ramoops_pstore_open */
-	unsigned int dump_read_cnt;
-	unsigned int console_read_cnt;
-	unsigned int max_ftrace_cnt;
-	unsigned int ftrace_read_cnt;
-	unsigned int pmsg_read_cnt;
-#ifdef CONFIG_PSTORE_BOOT_LOG
-	unsigned int boot_log_read_cnt;
-	unsigned int max_boot_log_cnt;
-#endif
-	struct pstore_info pstore;
-};
-
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
-			unsigned int memtype, u32 flags);
+			unsigned int memtype, u32 flags, char *label);
 void persistent_ram_free(struct persistent_ram_zone *prz);
 void persistent_ram_zap(struct persistent_ram_zone *prz);
 
@@ -124,6 +116,9 @@ void *persistent_ram_old(struct persistent_ram_zone *prz);
 void persistent_ram_free_old(struct persistent_ram_zone *prz);
 ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
 	char *str, size_t len);
+#ifdef CONFIG_PSTORE_BOOT_LOG
+ssize_t ramoops_pstore_read_for_boot_log(struct pstore_record *record);
+#endif
 
 /*
  * Ramoops platform data
@@ -145,7 +140,7 @@ struct ramoops_platform_data {
 	unsigned long	boot_log_size;
 	unsigned long	max_boot_log_cnt;
 #endif
-	int		dump_oops;
+	int		max_reason;
 	u32		flags;
 	struct persistent_ram_ecc_info ecc_info;
 };

kernel/printk/printk.c

@@ -3260,6 +3260,23 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 	rcu_read_unlock();
 }
 
+const char *kmsg_dump_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_SHUTDOWN:
+		return "Shutdown";
+	default:
+		return "Unknown";
+	}
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_reason_str);
+
 /**
  * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
  * @dumper: registered kmsg dumper