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7dcb7848ba
Add support for non-block devices (e.g. MTD). A non-block driver calls pstore_blk_register_device() to register iself. In addition, pstore/zone is updated to handle non-block devices, where an erase must be done before a write. Without this, there is no way to remove records stored to an MTD. Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com> Link: https://lore.kernel.org/lkml/20200511233229.27745-10-keescook@chromium.org/ Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
118 lines
3.9 KiB
C
118 lines
3.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PSTORE_BLK_H_
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#define __PSTORE_BLK_H_
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#include <linux/types.h>
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#include <linux/pstore.h>
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#include <linux/pstore_zone.h>
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/**
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* typedef pstore_blk_panic_write_op - panic write operation to block device
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*
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* @buf: the data to write
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* @start_sect: start sector to block device
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* @sects: sectors count on buf
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*
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* Return: On success, zero should be returned. Others excluding -ENOMSG
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* mean error. -ENOMSG means to try next zone.
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*
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* Panic write to block device must be aligned to SECTOR_SIZE.
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*/
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typedef int (*pstore_blk_panic_write_op)(const char *buf, sector_t start_sect,
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sector_t sects);
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/**
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* struct pstore_blk_info - pstore/blk registration details
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*
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* @major: Which major device number to support with pstore/blk
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* @flags: The supported PSTORE_FLAGS_* from linux/pstore.h.
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* @panic_write:The write operation only used for the panic case.
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* This can be NULL, but is recommended to avoid losing
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* crash data if the kernel's IO path or work queues are
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* broken during a panic.
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* @devt: The dev_t that pstore/blk has attached to.
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* @nr_sects: Number of sectors on @devt.
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* @start_sect: Starting sector on @devt.
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*/
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struct pstore_blk_info {
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unsigned int major;
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unsigned int flags;
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pstore_blk_panic_write_op panic_write;
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/* Filled in by pstore/blk after registration. */
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dev_t devt;
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sector_t nr_sects;
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sector_t start_sect;
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};
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int register_pstore_blk(struct pstore_blk_info *info);
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void unregister_pstore_blk(unsigned int major);
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/**
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* struct pstore_device_info - back-end pstore/blk driver structure.
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*
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* @total_size: The total size in bytes pstore/blk can use. It must be greater
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* than 4096 and be multiple of 4096.
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* @flags: Refer to macro starting with PSTORE_FLAGS defined in
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* linux/pstore.h. It means what front-ends this device support.
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* Zero means all backends for compatible.
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* @read: The general read operation. Both of the function parameters
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* @size and @offset are relative value to bock device (not the
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* whole disk).
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* On success, the number of bytes should be returned, others
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* means error.
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* @write: The same as @read, but the following error number:
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* -EBUSY means try to write again later.
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* -ENOMSG means to try next zone.
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* @erase: The general erase operation for device with special removing
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* job. Both of the function parameters @size and @offset are
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* relative value to storage.
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* Return 0 on success and others on failure.
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* @panic_write:The write operation only used for panic case. It's optional
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* if you do not care panic log. The parameters are relative
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* value to storage.
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* On success, the number of bytes should be returned, others
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* excluding -ENOMSG mean error. -ENOMSG means to try next zone.
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*/
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struct pstore_device_info {
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unsigned long total_size;
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unsigned int flags;
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pstore_zone_read_op read;
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pstore_zone_write_op write;
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pstore_zone_erase_op erase;
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pstore_zone_write_op panic_write;
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};
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int register_pstore_device(struct pstore_device_info *dev);
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void unregister_pstore_device(struct pstore_device_info *dev);
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/**
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* struct pstore_blk_config - the pstore_blk backend configuration
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*
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* @device: Name of the desired block device
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* @max_reason: Maximum kmsg dump reason to store to block device
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* @kmsg_size: Total size of for kmsg dumps
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* @pmsg_size: Total size of the pmsg storage area
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* @console_size: Total size of the console storage area
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* @ftrace_size: Total size for ftrace logging data (for all CPUs)
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*/
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struct pstore_blk_config {
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char device[80];
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enum kmsg_dump_reason max_reason;
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unsigned long kmsg_size;
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unsigned long pmsg_size;
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unsigned long console_size;
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unsigned long ftrace_size;
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};
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/**
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* pstore_blk_get_config - get a copy of the pstore_blk backend configuration
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*
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* @info: The sturct pstore_blk_config to be filled in
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*
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* Failure returns negative error code, and success returns 0.
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*/
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int pstore_blk_get_config(struct pstore_blk_config *info);
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#endif
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