Most pstore backends lack support for all the pstore frontends, only handling kmsg dump and not things like pmsg, console, and ftrace. Provide a way for drivers using pstore/blk to list which frontends they expect to support. Signed-off-by: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/1585126506-18635-4-git-send-email-liaoweixiong@xxxxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- fs/pstore/blk.c | 18 ++++++++++++++---- include/linux/pstore_blk.h | 4 +++- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c index e249b22ff55f..57d9d180511e 100644 --- a/fs/pstore/blk.c +++ b/fs/pstore/blk.c @@ -67,6 +67,9 @@ * * @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). @@ -79,6 +82,7 @@ */ struct psblk_device { unsigned long total_size; + unsigned int flags; psz_read_op read; psz_write_op write; psz_write_op panic_write; @@ -104,8 +108,11 @@ static int psblk_register_do(struct psblk_device *dev) return -ENOMEM; } -#define verify_size(name, alignsize) { \ - long _##name_ = (name); \ + /* zero means all backends for compatible */ + if (!dev->flags) + dev->flags = UINT_MAX; +#define verify_size(name, alignsize, enable) { \ + long _##name_ = (enable) ? (name) : 0; \ _##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \ if (_##name_ & ((alignsize) - 1)) { \ pr_info(#name " must align to %d\n", \ @@ -116,7 +123,7 @@ static int psblk_register_do(struct psblk_device *dev) pstore_zone_info->name = _##name_; \ } - verify_size(kmsg_size, 4096); + verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG); #undef verify_size pstore_zone_info->total_size = dev->total_size; @@ -312,6 +319,7 @@ static struct bdev_info *psblk_get_bdev_info(void) * psblk_register_blkdev() - register block device to pstore/blk * * @major: the major device number of registering device + * @flags: refer to macro starting with PSTORE_FLAGS defined in linux/pstore.h * @panic_write: the interface for panic case. * * Only the matching major to @blkdev can register. @@ -322,7 +330,8 @@ static struct bdev_info *psblk_get_bdev_info(void) * * 0 - OK * * Others - something error. */ -int psblk_register_blkdev(unsigned int major, psblk_panic_write_op panic_write) +int psblk_register_blkdev(unsigned int major, unsigned int flags, + psblk_panic_write_op panic_write) { struct block_device *bdev; struct psblk_device dev = {0}; @@ -353,6 +362,7 @@ int psblk_register_blkdev(unsigned int major, psblk_panic_write_op panic_write) blkdev_panic_write = panic_write; dev.total_size = psblk_bdev_size(bdev); + dev.flags = flags; dev.panic_write = panic_write ? psblk_blk_panic_write : NULL; dev.read = psblk_generic_blk_read; dev.write = psblk_generic_blk_write; diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h index 5ff465e3953e..d8f609e60288 100644 --- a/include/linux/pstore_blk.h +++ b/include/linux/pstore_blk.h @@ -4,6 +4,7 @@ #define __PSTORE_BLK_H_ #include <linux/types.h> +#include <linux/pstore.h> #include <linux/pstore_zone.h> /** @@ -20,7 +21,8 @@ typedef int (*psblk_panic_write_op)(const char *buf, sector_t start_sect, sector_t sects); -int psblk_register_blkdev(unsigned int major, psblk_panic_write_op panic_write); +int psblk_register_blkdev(unsigned int major, unsigned int flags, + psblk_panic_write_op panic_write); void psblk_unregister_blkdev(unsigned int major); int psblk_blkdev_info(dev_t *devt, sector_t *nr_sects, sector_t *start_sect); -- 1.9.1
