362 строки
9.1 KiB
C
362 строки
9.1 KiB
C
// 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 <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/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/init_syscalls.h>
|
|
#include <linux/mount.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
|
|
* See Documentation/admin-guide/pstore-blk.rst for details.
|
|
*/
|
|
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 file *psblk_file;
|
|
static struct pstore_device_info *pstore_device_info;
|
|
|
|
#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_; \
|
|
})
|
|
|
|
#define verify_size(name, alignsize, enabled) { \
|
|
long _##name_; \
|
|
if (enabled) \
|
|
_##name_ = check_size(name, alignsize); \
|
|
else \
|
|
_##name_ = 0; \
|
|
/* Synchronize module parameters with resuls. */ \
|
|
name = _##name_ / 1024; \
|
|
dev->zone.name = _##name_; \
|
|
}
|
|
|
|
static int __register_pstore_device(struct pstore_device_info *dev)
|
|
{
|
|
int ret;
|
|
|
|
lockdep_assert_held(&pstore_blk_lock);
|
|
|
|
if (!dev) {
|
|
pr_err("NULL device info\n");
|
|
return -EINVAL;
|
|
}
|
|
if (!dev->zone.total_size) {
|
|
pr_err("zero sized device\n");
|
|
return -EINVAL;
|
|
}
|
|
if (!dev->zone.read) {
|
|
pr_err("no read handler for device\n");
|
|
return -EINVAL;
|
|
}
|
|
if (!dev->zone.write) {
|
|
pr_err("no write handler for device\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* someone already registered before */
|
|
if (pstore_device_info)
|
|
return -EBUSY;
|
|
|
|
/* zero means not limit on which backends to attempt to store. */
|
|
if (!dev->flags)
|
|
dev->flags = UINT_MAX;
|
|
|
|
/* Copy in module parameters. */
|
|
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);
|
|
dev->zone.max_reason = max_reason;
|
|
|
|
/* Initialize required zone ownership details. */
|
|
dev->zone.name = KBUILD_MODNAME;
|
|
dev->zone.owner = THIS_MODULE;
|
|
|
|
ret = register_pstore_zone(&dev->zone);
|
|
if (ret == 0)
|
|
pstore_device_info = dev;
|
|
|
|
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_device_info && pstore_device_info == dev) {
|
|
unregister_pstore_zone(&dev->zone);
|
|
pstore_device_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);
|
|
|
|
static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos)
|
|
{
|
|
return kernel_read(psblk_file, buf, bytes, &pos);
|
|
}
|
|
|
|
static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes,
|
|
loff_t pos)
|
|
{
|
|
/* Console/Ftrace backend may handle buffer until flush dirty zones */
|
|
if (in_interrupt() || irqs_disabled())
|
|
return -EBUSY;
|
|
return kernel_write(psblk_file, buf, bytes, &pos);
|
|
}
|
|
|
|
/*
|
|
* This takes its configuration only from the module parameters now.
|
|
*/
|
|
static int __register_pstore_blk(struct pstore_device_info *dev,
|
|
const char *devpath)
|
|
{
|
|
int ret = -ENODEV;
|
|
|
|
lockdep_assert_held(&pstore_blk_lock);
|
|
|
|
psblk_file = filp_open(devpath, O_RDWR | O_DSYNC | O_NOATIME | O_EXCL, 0);
|
|
if (IS_ERR(psblk_file)) {
|
|
ret = PTR_ERR(psblk_file);
|
|
pr_err("failed to open '%s': %d!\n", devpath, ret);
|
|
goto err;
|
|
}
|
|
|
|
if (!S_ISBLK(file_inode(psblk_file)->i_mode)) {
|
|
pr_err("'%s' is not block device!\n", devpath);
|
|
goto err_fput;
|
|
}
|
|
|
|
dev->zone.total_size =
|
|
bdev_nr_bytes(I_BDEV(psblk_file->f_mapping->host));
|
|
|
|
ret = __register_pstore_device(dev);
|
|
if (ret)
|
|
goto err_fput;
|
|
|
|
return 0;
|
|
|
|
err_fput:
|
|
fput(psblk_file);
|
|
err:
|
|
psblk_file = NULL;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* 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);
|
|
|
|
|
|
#ifndef MODULE
|
|
static const char devname[] = "/dev/pstore-blk";
|
|
static __init const char *early_boot_devpath(const char *initial_devname)
|
|
{
|
|
/*
|
|
* During early boot the real root file system hasn't been
|
|
* mounted yet, and no device nodes are present yet. Use the
|
|
* same scheme to find the device that we use for mounting
|
|
* the root file system.
|
|
*/
|
|
dev_t dev = name_to_dev_t(initial_devname);
|
|
|
|
if (!dev) {
|
|
pr_err("failed to resolve '%s'!\n", initial_devname);
|
|
return initial_devname;
|
|
}
|
|
|
|
init_unlink(devname);
|
|
init_mknod(devname, S_IFBLK | 0600, new_encode_dev(dev));
|
|
|
|
return devname;
|
|
}
|
|
#else
|
|
static inline const char *early_boot_devpath(const char *initial_devname)
|
|
{
|
|
return initial_devname;
|
|
}
|
|
#endif
|
|
|
|
static int __init __best_effort_init(void)
|
|
{
|
|
struct pstore_device_info *best_effort_dev;
|
|
int ret;
|
|
|
|
/* No best-effort mode requested. */
|
|
if (!best_effort)
|
|
return 0;
|
|
|
|
/* Reject an empty blkdev. */
|
|
if (!blkdev[0]) {
|
|
pr_err("blkdev empty with best_effort=Y\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
best_effort_dev = kzalloc(sizeof(*best_effort_dev), GFP_KERNEL);
|
|
if (!best_effort_dev)
|
|
return -ENOMEM;
|
|
|
|
best_effort_dev->zone.read = psblk_generic_blk_read;
|
|
best_effort_dev->zone.write = psblk_generic_blk_write;
|
|
|
|
ret = __register_pstore_blk(best_effort_dev,
|
|
early_boot_devpath(blkdev));
|
|
if (ret)
|
|
kfree(best_effort_dev);
|
|
else
|
|
pr_info("attached %s (%lu) (no dedicated panic_write!)\n",
|
|
blkdev, best_effort_dev->zone.total_size);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __exit __best_effort_exit(void)
|
|
{
|
|
/*
|
|
* Currently, the only user of psblk_file is best_effort, so
|
|
* we can assume that pstore_device_info is associated with it.
|
|
* Once there are "real" blk devices, there will need to be a
|
|
* dedicated pstore_blk_info, etc.
|
|
*/
|
|
if (psblk_file) {
|
|
struct pstore_device_info *dev = pstore_device_info;
|
|
|
|
__unregister_pstore_device(dev);
|
|
kfree(dev);
|
|
fput(psblk_file);
|
|
psblk_file = NULL;
|
|
}
|
|
}
|
|
|
|
static int __init pstore_blk_init(void)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&pstore_blk_lock);
|
|
ret = __best_effort_init();
|
|
mutex_unlock(&pstore_blk_lock);
|
|
|
|
return ret;
|
|
}
|
|
late_initcall(pstore_blk_init);
|
|
|
|
static void __exit pstore_blk_exit(void)
|
|
{
|
|
mutex_lock(&pstore_blk_lock);
|
|
__best_effort_exit();
|
|
/* If we've been asked to unload, unregister any remaining device. */
|
|
__unregister_pstore_device(pstore_device_info);
|
|
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");
|