diff options
| -rw-r--r-- | fs/pstore/Kconfig | 64 | ||||
| -rw-r--r-- | fs/pstore/Makefile | 3 | ||||
| -rw-r--r-- | fs/pstore/blk.c | 434 | ||||
| -rw-r--r-- | include/linux/pstore_blk.h | 51 |
4 files changed, 552 insertions, 0 deletions
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig index 98d2457bdd9f..958bec75f907 100644 --- a/fs/pstore/Kconfig +++ b/fs/pstore/Kconfig @@ -160,3 +160,67 @@ config PSTORE_ZONE 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 + 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. + + 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 accept 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, 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. diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile index 58a967cbe4af..c270467aeece 100644 --- a/fs/pstore/Makefile +++ b/fs/pstore/Makefile @@ -15,3 +15,6 @@ 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 diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c new file mode 100644 index 000000000000..8f131c6e412e --- /dev/null +++ b/fs/pstore/blk.c @@ -0,0 +1,434 @@ +// 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)"); + +/* + * 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; +}; + +/** + * 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. + * @panic_write:The write operation only used for panic case. It's optional + * if you do not care panic log. The parameters and return value + * are the same as @read. + */ +struct pstore_device_info { + unsigned long total_size; + unsigned int flags; + pstore_zone_read_op read; + pstore_zone_write_op write; + pstore_zone_write_op panic_write; +}; + +static int psblk_register_do(struct pstore_device_info *dev) +{ + int ret; + + if (!dev || !dev->total_size || !dev->read || !dev->write) + return -EINVAL; + + mutex_lock(&pstore_blk_lock); + + /* someone already registered before */ + if (pstore_zone_info) { + mutex_unlock(&pstore_blk_lock); + return -EBUSY; + } + pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL); + if (!pstore_zone_info) { + mutex_unlock(&pstore_blk_lock); + 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_ = (enabled) ? (name) : 0; \ + _##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \ + if (_##name_ & ((alignsize) - 1)) { \ + pr_info(#name " must align to %d\n", \ + (alignsize)); \ + _##name_ = ALIGN(name, (alignsize)); \ + } \ + name = _##name_ / 1024; \ + pstore_zone_info->name = _##name_; \ + } + + verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG); +#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->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; + } + mutex_unlock(&pstore_blk_lock); + return ret; +} + +static void psblk_unregister_do(struct pstore_device_info *dev) +{ + mutex_lock(&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; + } + mutex_unlock(&pstore_blk_lock); +} + +/** + * 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); + 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 || 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.panic_write = info->panic_write ? psblk_blk_panic_write : NULL; + + ret = psblk_register_do(&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) { + psblk_unregister_do(&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); + +static void __exit pstore_blk_exit(void) +{ + mutex_lock(&pstore_blk_lock); + if (psblk_bdev) + __unregister_pstore_blk(MAJOR(psblk_bdev->bd_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"); diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h new file mode 100644 index 000000000000..4501977b1336 --- /dev/null +++ b/include/linux/pstore_blk.h @@ -0,0 +1,51 @@ +/* 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 mean error. + * + * 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); + +#endif |