Merge tag 'pstore-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "Fixes and new features for pstore.

  This is a pretty big set of changes (relative to past pstore pulls),
  but it has been in -next for a while. The biggest change here is the
  ability to support a block device as a pstore backend, which has been
  desired for a while. A lot of additional fixes and refactorings are
  also included, mostly in support of the new features.

   - refactor pstore locking for safer module unloading (Kees Cook)

   - remove orphaned records from pstorefs when backend unloaded (Kees
     Cook)

   - refactor dump_oops parameter into max_reason (Pavel Tatashin)

   - introduce pstore/zone for common code for contiguous storage
     (WeiXiong Liao)

   - introduce pstore/blk for block device backend (WeiXiong Liao)

   - introduce mtd backend (WeiXiong Liao)"

* tag 'pstore-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (35 commits)
  mtd: Support kmsg dumper based on pstore/blk
  pstore/blk: Introduce "best_effort" mode
  pstore/blk: Support non-block storage devices
  pstore/blk: Provide way to query pstore configuration
  pstore/zone: Provide way to skip "broken" zone for MTD devices
  Documentation: Add details for pstore/blk
  pstore/zone,blk: Add ftrace frontend support
  pstore/zone,blk: Add console frontend support
  pstore/zone,blk: Add support for pmsg frontend
  pstore/blk: Introduce backend for block devices
  pstore/zone: Introduce common layer to manage storage zones
  ramoops: Add "max-reason" optional field to ramoops DT node
  pstore/ram: Introduce max_reason and convert dump_oops
  pstore/platform: Pass max_reason to kmesg dump
  printk: Introduce kmsg_dump_reason_str()
  printk: honor the max_reason field in kmsg_dumper
  printk: Collapse shutdown types into a single dump reason
  pstore/ftrace: Provide ftrace log merging routine
  pstore/ram: Refactor ftrace buffer merging
  pstore/ram: Refactor DT size parsing
  ...

5 files changed, 196 insertions, 5 deletions

diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 2e7a1e032c71..3378bcbe585e 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -25,9 +25,8 @@ enum kmsg_dump_reason {
 	KMSG_DUMP_PANIC,
 	KMSG_DUMP_OOPS,
 	KMSG_DUMP_EMERG,
-	KMSG_DUMP_RESTART,
-	KMSG_DUMP_HALT,
-	KMSG_DUMP_POWEROFF,
+	KMSG_DUMP_SHUTDOWN,
+	KMSG_DUMP_MAX
 };
 
 /**
@@ -71,6 +70,8 @@ void kmsg_dump_rewind(struct kmsg_dumper *dumper);
 int kmsg_dump_register(struct kmsg_dumper *dumper);
 
 int kmsg_dump_unregister(struct kmsg_dumper *dumper);
+
+const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason);
 #else
 static inline void kmsg_dump(enum kmsg_dump_reason reason)
 {
@@ -112,6 +113,11 @@ static inline int kmsg_dump_unregister(struct kmsg_dumper *dumper)
 {
 	return -EINVAL;
 }
+
+static inline const char *kmsg_dump_reason_str(enum kmsg_dump_reason reason)
+{
+	return "Disabled";
+}
 #endif
 
 #endif /* _LINUX_KMSG_DUMP_H */
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e779441e6d26..eb93a54cff31 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -96,6 +96,12 @@ 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:
@@ -170,7 +176,7 @@ struct pstore_record {
  */
 struct pstore_info {
 	struct module	*owner;
-	char		*name;
+	const char	*name;
 
 	struct semaphore buf_lock;
 	char		*buf;
@@ -179,6 +185,7 @@ struct pstore_info {
 	struct mutex	read_mutex;
 
 	int		flags;
+	int		max_reason;
 	void		*data;
 
 	int		(*open)(struct pstore_info *psi);
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
new file mode 100644
index 000000000000..61e914522b01
--- /dev/null
+++ b/include/linux/pstore_blk.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __PSTORE_BLK_H_
+#define __PSTORE_BLK_H_
+
+#include <linux/types.h>
+#include <linux/pstore.h>
+#include <linux/pstore_zone.h>
+
+/**
+ * typedef pstore_blk_panic_write_op - panic write operation to block device
+ *
+ * @buf: the data to write
+ * @start_sect: start sector to block device
+ * @sects: sectors count on buf
+ *
+ * Return: On success, zero should be returned. Others excluding -ENOMSG
+ * mean error. -ENOMSG means to try next zone.
+ *
+ * Panic write to block device must be aligned to SECTOR_SIZE.
+ */
+typedef int (*pstore_blk_panic_write_op)(const char *buf, sector_t start_sect,
+		sector_t sects);
+
+/**
+ * struct pstore_blk_info - pstore/blk registration details
+ *
+ * @major:	Which major device number to support with pstore/blk
+ * @flags:	The supported PSTORE_FLAGS_* from linux/pstore.h.
+ * @panic_write:The write operation only used for the panic case.
+ *		This can be NULL, but is recommended to avoid losing
+ *		crash data if the kernel's IO path or work queues are
+ *		broken during a panic.
+ * @devt:	The dev_t that pstore/blk has attached to.
+ * @nr_sects:	Number of sectors on @devt.
+ * @start_sect:	Starting sector on @devt.
+ */
+struct pstore_blk_info {
+	unsigned int major;
+	unsigned int flags;
+	pstore_blk_panic_write_op panic_write;
+
+	/* Filled in by pstore/blk after registration. */
+	dev_t devt;
+	sector_t nr_sects;
+	sector_t start_sect;
+};
+
+int  register_pstore_blk(struct pstore_blk_info *info);
+void unregister_pstore_blk(unsigned int major);
+
+/**
+ * struct pstore_device_info - back-end pstore/blk driver structure.
+ *
+ * @total_size: The total size in bytes pstore/blk can use. It must be greater
+ *		than 4096 and be multiple of 4096.
+ * @flags:	Refer to macro starting with PSTORE_FLAGS defined in
+ *		linux/pstore.h. It means what front-ends this device support.
+ *		Zero means all backends for compatible.
+ * @read:	The general read operation. Both of the function parameters
+ *		@size and @offset are relative value to bock device (not the
+ *		whole disk).
+ *		On success, the number of bytes should be returned, others
+ *		means error.
+ * @write:	The same as @read, but the following error number:
+ *		-EBUSY means try to write again later.
+ *		-ENOMSG means to try next zone.
+ * @erase:	The general erase operation for device with special removing
+ *		job. Both of the function parameters @size and @offset are
+ *		relative value to storage.
+ *		Return 0 on success and others on failure.
+ * @panic_write:The write operation only used for panic case. It's optional
+ *		if you do not care panic log. The parameters are relative
+ *		value to storage.
+ *		On success, the number of bytes should be returned, others
+ *		excluding -ENOMSG mean error. -ENOMSG means to try next zone.
+ */
+struct pstore_device_info {
+	unsigned long total_size;
+	unsigned int flags;
+	pstore_zone_read_op read;
+	pstore_zone_write_op write;
+	pstore_zone_erase_op erase;
+	pstore_zone_write_op panic_write;
+};
+
+int  register_pstore_device(struct pstore_device_info *dev);
+void unregister_pstore_device(struct pstore_device_info *dev);
+
+/**
+ * struct pstore_blk_config - the pstore_blk backend configuration
+ *
+ * @device:		Name of the desired block device
+ * @max_reason:		Maximum kmsg dump reason to store to block device
+ * @kmsg_size:		Total size of for kmsg dumps
+ * @pmsg_size:		Total size of the pmsg storage area
+ * @console_size:	Total size of the console storage area
+ * @ftrace_size:	Total size for ftrace logging data (for all CPUs)
+ */
+struct pstore_blk_config {
+	char device[80];
+	enum kmsg_dump_reason max_reason;
+	unsigned long kmsg_size;
+	unsigned long pmsg_size;
+	unsigned long console_size;
+	unsigned long ftrace_size;
+};
+
+/**
+ * pstore_blk_get_config - get a copy of the pstore_blk backend configuration
+ *
+ * @info:	The sturct pstore_blk_config to be filled in
+ *
+ * Failure returns negative error code, and success returns 0.
+ */
+int pstore_blk_get_config(struct pstore_blk_config *info);
+
+#endif
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 9cb9b9067298..9f16afec7290 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -133,7 +133,7 @@ struct ramoops_platform_data {
 	unsigned long	console_size;
 	unsigned long	ftrace_size;
 	unsigned long	pmsg_size;
-	int		dump_oops;
+	int		max_reason;
 	u32		flags;
 	struct persistent_ram_ecc_info ecc_info;
 };
diff --git a/include/linux/pstore_zone.h b/include/linux/pstore_zone.h
new file mode 100644
index 000000000000..1e35eaa33e5e
--- /dev/null
+++ b/include/linux/pstore_zone.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __PSTORE_ZONE_H_
+#define __PSTORE_ZONE_H_
+
+#include <linux/types.h>
+
+typedef ssize_t (*pstore_zone_read_op)(char *, size_t, loff_t);
+typedef ssize_t (*pstore_zone_write_op)(const char *, size_t, loff_t);
+typedef ssize_t (*pstore_zone_erase_op)(size_t, loff_t);
+/**
+ * struct pstore_zone_info - pstore/zone back-end driver structure
+ *
+ * @owner:	Module which is responsible for this back-end driver.
+ * @name:	Name of the back-end driver.
+ * @total_size: The total size in bytes pstore/zone can use. It must be greater
+ *		than 4096 and be multiple of 4096.
+ * @kmsg_size:	The size of oops/panic zone. Zero means disabled, otherwise,
+ *		it must be multiple of SECTOR_SIZE(512 Bytes).
+ * @max_reason: Maximum kmsg dump reason to store.
+ * @pmsg_size:	The size of pmsg zone which is the same as @kmsg_size.
+ * @console_size:The size of console zone which is the same as @kmsg_size.
+ * @ftrace_size:The size of ftrace zone which is the same as @kmsg_size.
+ * @read:	The general read operation. Both of the function parameters
+ *		@size and @offset are relative value to storage.
+ *		On success, the number of bytes should be returned, others
+ *		mean error.
+ * @write:	The same as @read, but the following error number:
+ *		-EBUSY means try to write again later.
+ *		-ENOMSG means to try next zone.
+ * @erase:	The general erase operation for device with special removing
+ *		job. Both of the function parameters @size and @offset are
+ *		relative value to storage.
+ *		Return 0 on success and others on failure.
+ * @panic_write:The write operation only used for panic case. It's optional
+ *		if you do not care panic log. The parameters are relative
+ *		value to storage.
+ *		On success, the number of bytes should be returned, others
+ *		excluding -ENOMSG mean error. -ENOMSG means to try next zone.
+ */
+struct pstore_zone_info {
+	struct module *owner;
+	const char *name;
+
+	unsigned long total_size;
+	unsigned long kmsg_size;
+	int max_reason;
+	unsigned long pmsg_size;
+	unsigned long console_size;
+	unsigned long ftrace_size;
+	pstore_zone_read_op read;
+	pstore_zone_write_op write;
+	pstore_zone_erase_op erase;
+	pstore_zone_write_op panic_write;
+};
+
+extern int register_pstore_zone(struct pstore_zone_info *info);
+extern void unregister_pstore_zone(struct pstore_zone_info *info);
+
+#endif