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17639f67 WL |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Implements pstore backend driver that write to block (or non-block) storage | |
4 | * devices, using the pstore/zone API. | |
5 | */ | |
6 | ||
7 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/module.h> | |
11 | #include "../../block/blk.h" | |
12 | #include <linux/blkdev.h> | |
13 | #include <linux/string.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/of_address.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/pstore_blk.h> | |
18 | #include <linux/mount.h> | |
19 | #include <linux/uio.h> | |
20 | ||
21 | static long kmsg_size = CONFIG_PSTORE_BLK_KMSG_SIZE; | |
22 | module_param(kmsg_size, long, 0400); | |
23 | MODULE_PARM_DESC(kmsg_size, "kmsg dump record size in kbytes"); | |
24 | ||
25 | static int max_reason = CONFIG_PSTORE_BLK_MAX_REASON; | |
26 | module_param(max_reason, int, 0400); | |
27 | MODULE_PARM_DESC(max_reason, | |
28 | "maximum reason for kmsg dump (default 2: Oops and Panic)"); | |
29 | ||
0dc06826 WL |
30 | #if IS_ENABLED(CONFIG_PSTORE_PMSG) |
31 | static long pmsg_size = CONFIG_PSTORE_BLK_PMSG_SIZE; | |
32 | #else | |
33 | static long pmsg_size = -1; | |
34 | #endif | |
35 | module_param(pmsg_size, long, 0400); | |
36 | MODULE_PARM_DESC(pmsg_size, "pmsg size in kbytes"); | |
37 | ||
cc9c4d1b WL |
38 | #if IS_ENABLED(CONFIG_PSTORE_CONSOLE) |
39 | static long console_size = CONFIG_PSTORE_BLK_CONSOLE_SIZE; | |
40 | #else | |
41 | static long console_size = -1; | |
42 | #endif | |
43 | module_param(console_size, long, 0400); | |
44 | MODULE_PARM_DESC(console_size, "console size in kbytes"); | |
45 | ||
34327e9f WL |
46 | #if IS_ENABLED(CONFIG_PSTORE_FTRACE) |
47 | static long ftrace_size = CONFIG_PSTORE_BLK_FTRACE_SIZE; | |
48 | #else | |
49 | static long ftrace_size = -1; | |
50 | #endif | |
51 | module_param(ftrace_size, long, 0400); | |
52 | MODULE_PARM_DESC(ftrace_size, "ftrace size in kbytes"); | |
53 | ||
f8feafea KC |
54 | static bool best_effort; |
55 | module_param(best_effort, bool, 0400); | |
56 | MODULE_PARM_DESC(best_effort, "use best effort to write (i.e. do not require storage driver pstore support, default: off)"); | |
57 | ||
17639f67 WL |
58 | /* |
59 | * blkdev - the block device to use for pstore storage | |
60 | * | |
61 | * Usually, this will be a partition of a block device. | |
62 | * | |
63 | * blkdev accepts the following variants: | |
64 | * 1) <hex_major><hex_minor> device number in hexadecimal representation, | |
65 | * with no leading 0x, for example b302. | |
66 | * 2) /dev/<disk_name> represents the device number of disk | |
67 | * 3) /dev/<disk_name><decimal> represents the device number | |
68 | * of partition - device number of disk plus the partition number | |
69 | * 4) /dev/<disk_name>p<decimal> - same as the above, that form is | |
70 | * used when disk name of partitioned disk ends on a digit. | |
71 | * 5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the | |
72 | * unique id of a partition if the partition table provides it. | |
73 | * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS | |
74 | * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- | |
75 | * filled hex representation of the 32-bit "NT disk signature", and PP | |
76 | * is a zero-filled hex representation of the 1-based partition number. | |
77 | * 6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to | |
78 | * a partition with a known unique id. | |
79 | * 7) <major>:<minor> major and minor number of the device separated by | |
80 | * a colon. | |
81 | */ | |
82 | static char blkdev[80] = CONFIG_PSTORE_BLK_BLKDEV; | |
83 | module_param_string(blkdev, blkdev, 80, 0400); | |
84 | MODULE_PARM_DESC(blkdev, "block device for pstore storage"); | |
85 | ||
86 | /* | |
87 | * All globals must only be accessed under the pstore_blk_lock | |
88 | * during the register/unregister functions. | |
89 | */ | |
90 | static DEFINE_MUTEX(pstore_blk_lock); | |
91 | static struct block_device *psblk_bdev; | |
92 | static struct pstore_zone_info *pstore_zone_info; | |
93 | static pstore_blk_panic_write_op blkdev_panic_write; | |
94 | ||
95 | struct bdev_info { | |
96 | dev_t devt; | |
97 | sector_t nr_sects; | |
98 | sector_t start_sect; | |
99 | }; | |
100 | ||
1525fb3b WL |
101 | #define check_size(name, alignsize) ({ \ |
102 | long _##name_ = (name); \ | |
103 | _##name_ = _##name_ <= 0 ? 0 : (_##name_ * 1024); \ | |
104 | if (_##name_ & ((alignsize) - 1)) { \ | |
105 | pr_info(#name " must align to %d\n", \ | |
106 | (alignsize)); \ | |
107 | _##name_ = ALIGN(name, (alignsize)); \ | |
108 | } \ | |
109 | _##name_; \ | |
110 | }) | |
111 | ||
7dcb7848 | 112 | static int __register_pstore_device(struct pstore_device_info *dev) |
17639f67 WL |
113 | { |
114 | int ret; | |
115 | ||
7dcb7848 WL |
116 | lockdep_assert_held(&pstore_blk_lock); |
117 | ||
17639f67 WL |
118 | if (!dev || !dev->total_size || !dev->read || !dev->write) |
119 | return -EINVAL; | |
120 | ||
17639f67 | 121 | /* someone already registered before */ |
7dcb7848 | 122 | if (pstore_zone_info) |
17639f67 | 123 | return -EBUSY; |
7dcb7848 | 124 | |
17639f67 | 125 | pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL); |
7dcb7848 | 126 | if (!pstore_zone_info) |
17639f67 | 127 | return -ENOMEM; |
17639f67 WL |
128 | |
129 | /* zero means not limit on which backends to attempt to store. */ | |
130 | if (!dev->flags) | |
131 | dev->flags = UINT_MAX; | |
132 | ||
133 | #define verify_size(name, alignsize, enabled) { \ | |
1525fb3b WL |
134 | long _##name_; \ |
135 | if (enabled) \ | |
136 | _##name_ = check_size(name, alignsize); \ | |
137 | else \ | |
138 | _##name_ = 0; \ | |
17639f67 WL |
139 | name = _##name_ / 1024; \ |
140 | pstore_zone_info->name = _##name_; \ | |
141 | } | |
142 | ||
143 | verify_size(kmsg_size, 4096, dev->flags & PSTORE_FLAGS_DMESG); | |
0dc06826 | 144 | verify_size(pmsg_size, 4096, dev->flags & PSTORE_FLAGS_PMSG); |
cc9c4d1b | 145 | verify_size(console_size, 4096, dev->flags & PSTORE_FLAGS_CONSOLE); |
34327e9f | 146 | verify_size(ftrace_size, 4096, dev->flags & PSTORE_FLAGS_FTRACE); |
17639f67 WL |
147 | #undef verify_size |
148 | ||
149 | pstore_zone_info->total_size = dev->total_size; | |
150 | pstore_zone_info->max_reason = max_reason; | |
151 | pstore_zone_info->read = dev->read; | |
152 | pstore_zone_info->write = dev->write; | |
7dcb7848 | 153 | pstore_zone_info->erase = dev->erase; |
17639f67 WL |
154 | pstore_zone_info->panic_write = dev->panic_write; |
155 | pstore_zone_info->name = KBUILD_MODNAME; | |
156 | pstore_zone_info->owner = THIS_MODULE; | |
157 | ||
158 | ret = register_pstore_zone(pstore_zone_info); | |
159 | if (ret) { | |
160 | kfree(pstore_zone_info); | |
161 | pstore_zone_info = NULL; | |
162 | } | |
7dcb7848 WL |
163 | return ret; |
164 | } | |
165 | /** | |
166 | * register_pstore_device() - register non-block device to pstore/blk | |
167 | * | |
168 | * @dev: non-block device information | |
169 | * | |
170 | * Return: | |
171 | * * 0 - OK | |
172 | * * Others - something error. | |
173 | */ | |
174 | int register_pstore_device(struct pstore_device_info *dev) | |
175 | { | |
176 | int ret; | |
177 | ||
178 | mutex_lock(&pstore_blk_lock); | |
179 | ret = __register_pstore_device(dev); | |
17639f67 | 180 | mutex_unlock(&pstore_blk_lock); |
7dcb7848 | 181 | |
17639f67 WL |
182 | return ret; |
183 | } | |
7dcb7848 | 184 | EXPORT_SYMBOL_GPL(register_pstore_device); |
17639f67 | 185 | |
7dcb7848 | 186 | static void __unregister_pstore_device(struct pstore_device_info *dev) |
17639f67 | 187 | { |
7dcb7848 | 188 | lockdep_assert_held(&pstore_blk_lock); |
17639f67 WL |
189 | if (pstore_zone_info && pstore_zone_info->read == dev->read) { |
190 | unregister_pstore_zone(pstore_zone_info); | |
191 | kfree(pstore_zone_info); | |
192 | pstore_zone_info = NULL; | |
193 | } | |
7dcb7848 WL |
194 | } |
195 | ||
196 | /** | |
197 | * unregister_pstore_device() - unregister non-block device from pstore/blk | |
198 | * | |
199 | * @dev: non-block device information | |
200 | */ | |
201 | void unregister_pstore_device(struct pstore_device_info *dev) | |
202 | { | |
203 | mutex_lock(&pstore_blk_lock); | |
204 | __unregister_pstore_device(dev); | |
17639f67 WL |
205 | mutex_unlock(&pstore_blk_lock); |
206 | } | |
7dcb7848 | 207 | EXPORT_SYMBOL_GPL(unregister_pstore_device); |
17639f67 WL |
208 | |
209 | /** | |
210 | * psblk_get_bdev() - open block device | |
211 | * | |
212 | * @holder: Exclusive holder identifier | |
213 | * @info: Information about bdev to fill in | |
214 | * | |
215 | * Return: pointer to block device on success and others on error. | |
216 | * | |
217 | * On success, the returned block_device has reference count of one. | |
218 | */ | |
219 | static struct block_device *psblk_get_bdev(void *holder, | |
220 | struct bdev_info *info) | |
221 | { | |
222 | struct block_device *bdev = ERR_PTR(-ENODEV); | |
223 | fmode_t mode = FMODE_READ | FMODE_WRITE; | |
224 | sector_t nr_sects; | |
225 | ||
226 | lockdep_assert_held(&pstore_blk_lock); | |
227 | ||
228 | if (pstore_zone_info) | |
229 | return ERR_PTR(-EBUSY); | |
230 | ||
231 | if (!blkdev[0]) | |
232 | return ERR_PTR(-ENODEV); | |
233 | ||
234 | if (holder) | |
235 | mode |= FMODE_EXCL; | |
236 | bdev = blkdev_get_by_path(blkdev, mode, holder); | |
237 | if (IS_ERR(bdev)) { | |
238 | dev_t devt; | |
239 | ||
240 | devt = name_to_dev_t(blkdev); | |
241 | if (devt == 0) | |
242 | return ERR_PTR(-ENODEV); | |
243 | bdev = blkdev_get_by_dev(devt, mode, holder); | |
244 | if (IS_ERR(bdev)) | |
245 | return bdev; | |
246 | } | |
247 | ||
248 | nr_sects = part_nr_sects_read(bdev->bd_part); | |
249 | if (!nr_sects) { | |
250 | pr_err("not enough space for '%s'\n", blkdev); | |
251 | blkdev_put(bdev, mode); | |
252 | return ERR_PTR(-ENOSPC); | |
253 | } | |
254 | ||
255 | if (info) { | |
256 | info->devt = bdev->bd_dev; | |
257 | info->nr_sects = nr_sects; | |
258 | info->start_sect = get_start_sect(bdev); | |
259 | } | |
260 | ||
261 | return bdev; | |
262 | } | |
263 | ||
264 | static void psblk_put_bdev(struct block_device *bdev, void *holder) | |
265 | { | |
266 | fmode_t mode = FMODE_READ | FMODE_WRITE; | |
267 | ||
268 | lockdep_assert_held(&pstore_blk_lock); | |
269 | ||
270 | if (!bdev) | |
271 | return; | |
272 | ||
273 | if (holder) | |
274 | mode |= FMODE_EXCL; | |
275 | blkdev_put(bdev, mode); | |
276 | } | |
277 | ||
278 | static ssize_t psblk_generic_blk_read(char *buf, size_t bytes, loff_t pos) | |
279 | { | |
280 | struct block_device *bdev = psblk_bdev; | |
281 | struct file file; | |
282 | struct kiocb kiocb; | |
283 | struct iov_iter iter; | |
284 | struct kvec iov = {.iov_base = buf, .iov_len = bytes}; | |
285 | ||
286 | if (!bdev) | |
287 | return -ENODEV; | |
288 | ||
289 | memset(&file, 0, sizeof(struct file)); | |
290 | file.f_mapping = bdev->bd_inode->i_mapping; | |
291 | file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME; | |
292 | file.f_inode = bdev->bd_inode; | |
293 | file_ra_state_init(&file.f_ra, file.f_mapping); | |
294 | ||
295 | init_sync_kiocb(&kiocb, &file); | |
296 | kiocb.ki_pos = pos; | |
297 | iov_iter_kvec(&iter, READ, &iov, 1, bytes); | |
298 | ||
299 | return generic_file_read_iter(&kiocb, &iter); | |
300 | } | |
301 | ||
302 | static ssize_t psblk_generic_blk_write(const char *buf, size_t bytes, | |
303 | loff_t pos) | |
304 | { | |
305 | struct block_device *bdev = psblk_bdev; | |
306 | struct iov_iter iter; | |
307 | struct kiocb kiocb; | |
308 | struct file file; | |
309 | ssize_t ret; | |
310 | struct kvec iov = {.iov_base = (void *)buf, .iov_len = bytes}; | |
311 | ||
312 | if (!bdev) | |
313 | return -ENODEV; | |
314 | ||
315 | /* Console/Ftrace backend may handle buffer until flush dirty zones */ | |
316 | if (in_interrupt() || irqs_disabled()) | |
317 | return -EBUSY; | |
318 | ||
319 | memset(&file, 0, sizeof(struct file)); | |
320 | file.f_mapping = bdev->bd_inode->i_mapping; | |
321 | file.f_flags = O_DSYNC | __O_SYNC | O_NOATIME; | |
322 | file.f_inode = bdev->bd_inode; | |
323 | ||
324 | init_sync_kiocb(&kiocb, &file); | |
325 | kiocb.ki_pos = pos; | |
326 | iov_iter_kvec(&iter, WRITE, &iov, 1, bytes); | |
327 | ||
328 | inode_lock(bdev->bd_inode); | |
329 | ret = generic_write_checks(&kiocb, &iter); | |
330 | if (ret > 0) | |
331 | ret = generic_perform_write(&file, &iter, pos); | |
332 | inode_unlock(bdev->bd_inode); | |
333 | ||
334 | if (likely(ret > 0)) { | |
335 | const struct file_operations f_op = {.fsync = blkdev_fsync}; | |
336 | ||
337 | file.f_op = &f_op; | |
338 | kiocb.ki_pos += ret; | |
339 | ret = generic_write_sync(&kiocb, ret); | |
340 | } | |
341 | return ret; | |
342 | } | |
343 | ||
344 | static ssize_t psblk_blk_panic_write(const char *buf, size_t size, | |
345 | loff_t off) | |
346 | { | |
347 | int ret; | |
348 | ||
349 | if (!blkdev_panic_write) | |
350 | return -EOPNOTSUPP; | |
351 | ||
352 | /* size and off must align to SECTOR_SIZE for block device */ | |
353 | ret = blkdev_panic_write(buf, off >> SECTOR_SHIFT, | |
354 | size >> SECTOR_SHIFT); | |
335426c6 WL |
355 | /* try next zone */ |
356 | if (ret == -ENOMSG) | |
357 | return ret; | |
17639f67 WL |
358 | return ret ? -EIO : size; |
359 | } | |
360 | ||
361 | static int __register_pstore_blk(struct pstore_blk_info *info) | |
362 | { | |
363 | char bdev_name[BDEVNAME_SIZE]; | |
364 | struct block_device *bdev; | |
365 | struct pstore_device_info dev; | |
366 | struct bdev_info binfo; | |
367 | void *holder = blkdev; | |
368 | int ret = -ENODEV; | |
369 | ||
370 | lockdep_assert_held(&pstore_blk_lock); | |
371 | ||
372 | /* hold bdev exclusively */ | |
373 | memset(&binfo, 0, sizeof(binfo)); | |
374 | bdev = psblk_get_bdev(holder, &binfo); | |
375 | if (IS_ERR(bdev)) { | |
376 | pr_err("failed to open '%s'!\n", blkdev); | |
377 | return PTR_ERR(bdev); | |
378 | } | |
379 | ||
380 | /* only allow driver matching the @blkdev */ | |
f8feafea KC |
381 | if (!binfo.devt || (!best_effort && |
382 | MAJOR(binfo.devt) != info->major)) { | |
17639f67 WL |
383 | pr_debug("invalid major %u (expect %u)\n", |
384 | info->major, MAJOR(binfo.devt)); | |
385 | ret = -ENODEV; | |
386 | goto err_put_bdev; | |
387 | } | |
388 | ||
389 | /* psblk_bdev must be assigned before register to pstore/blk */ | |
390 | psblk_bdev = bdev; | |
391 | blkdev_panic_write = info->panic_write; | |
392 | ||
393 | /* Copy back block device details. */ | |
394 | info->devt = binfo.devt; | |
395 | info->nr_sects = binfo.nr_sects; | |
396 | info->start_sect = binfo.start_sect; | |
397 | ||
398 | memset(&dev, 0, sizeof(dev)); | |
399 | dev.total_size = info->nr_sects << SECTOR_SHIFT; | |
400 | dev.flags = info->flags; | |
401 | dev.read = psblk_generic_blk_read; | |
402 | dev.write = psblk_generic_blk_write; | |
7dcb7848 | 403 | dev.erase = NULL; |
17639f67 WL |
404 | dev.panic_write = info->panic_write ? psblk_blk_panic_write : NULL; |
405 | ||
7dcb7848 | 406 | ret = __register_pstore_device(&dev); |
17639f67 WL |
407 | if (ret) |
408 | goto err_put_bdev; | |
409 | ||
410 | bdevname(bdev, bdev_name); | |
411 | pr_info("attached %s%s\n", bdev_name, | |
412 | info->panic_write ? "" : " (no dedicated panic_write!)"); | |
413 | return 0; | |
414 | ||
415 | err_put_bdev: | |
416 | psblk_bdev = NULL; | |
417 | blkdev_panic_write = NULL; | |
418 | psblk_put_bdev(bdev, holder); | |
419 | return ret; | |
420 | } | |
421 | ||
422 | /** | |
423 | * register_pstore_blk() - register block device to pstore/blk | |
424 | * | |
425 | * @info: details on the desired block device interface | |
426 | * | |
427 | * Return: | |
428 | * * 0 - OK | |
429 | * * Others - something error. | |
430 | */ | |
431 | int register_pstore_blk(struct pstore_blk_info *info) | |
432 | { | |
433 | int ret; | |
434 | ||
435 | mutex_lock(&pstore_blk_lock); | |
436 | ret = __register_pstore_blk(info); | |
437 | mutex_unlock(&pstore_blk_lock); | |
438 | ||
439 | return ret; | |
440 | } | |
441 | EXPORT_SYMBOL_GPL(register_pstore_blk); | |
442 | ||
443 | static void __unregister_pstore_blk(unsigned int major) | |
444 | { | |
445 | struct pstore_device_info dev = { .read = psblk_generic_blk_read }; | |
446 | void *holder = blkdev; | |
447 | ||
448 | lockdep_assert_held(&pstore_blk_lock); | |
449 | if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) { | |
7dcb7848 | 450 | __unregister_pstore_device(&dev); |
17639f67 WL |
451 | psblk_put_bdev(psblk_bdev, holder); |
452 | blkdev_panic_write = NULL; | |
453 | psblk_bdev = NULL; | |
454 | } | |
455 | } | |
456 | ||
457 | /** | |
458 | * unregister_pstore_blk() - unregister block device from pstore/blk | |
459 | * | |
460 | * @major: the major device number of device | |
461 | */ | |
462 | void unregister_pstore_blk(unsigned int major) | |
463 | { | |
464 | mutex_lock(&pstore_blk_lock); | |
465 | __unregister_pstore_blk(major); | |
466 | mutex_unlock(&pstore_blk_lock); | |
467 | } | |
468 | EXPORT_SYMBOL_GPL(unregister_pstore_blk); | |
469 | ||
1525fb3b WL |
470 | /* get information of pstore/blk */ |
471 | int pstore_blk_get_config(struct pstore_blk_config *info) | |
472 | { | |
473 | strncpy(info->device, blkdev, 80); | |
474 | info->max_reason = max_reason; | |
475 | info->kmsg_size = check_size(kmsg_size, 4096); | |
476 | info->pmsg_size = check_size(pmsg_size, 4096); | |
477 | info->ftrace_size = check_size(ftrace_size, 4096); | |
478 | info->console_size = check_size(console_size, 4096); | |
479 | ||
480 | return 0; | |
481 | } | |
482 | EXPORT_SYMBOL_GPL(pstore_blk_get_config); | |
483 | ||
f8feafea KC |
484 | static int __init pstore_blk_init(void) |
485 | { | |
486 | struct pstore_blk_info info = { }; | |
487 | int ret = 0; | |
488 | ||
489 | mutex_lock(&pstore_blk_lock); | |
490 | if (!pstore_zone_info && best_effort && blkdev[0]) | |
491 | ret = __register_pstore_blk(&info); | |
492 | mutex_unlock(&pstore_blk_lock); | |
493 | ||
494 | return ret; | |
495 | } | |
496 | late_initcall(pstore_blk_init); | |
497 | ||
17639f67 WL |
498 | static void __exit pstore_blk_exit(void) |
499 | { | |
500 | mutex_lock(&pstore_blk_lock); | |
501 | if (psblk_bdev) | |
502 | __unregister_pstore_blk(MAJOR(psblk_bdev->bd_dev)); | |
7dcb7848 WL |
503 | else { |
504 | struct pstore_device_info dev = { }; | |
505 | ||
506 | if (pstore_zone_info) | |
507 | dev.read = pstore_zone_info->read; | |
508 | __unregister_pstore_device(&dev); | |
509 | } | |
17639f67 WL |
510 | mutex_unlock(&pstore_blk_lock); |
511 | } | |
512 | module_exit(pstore_blk_exit); | |
513 | ||
514 | MODULE_LICENSE("GPL"); | |
515 | MODULE_AUTHOR("WeiXiong Liao <liaoweixiong@allwinnertech.com>"); | |
516 | MODULE_AUTHOR("Kees Cook <keescook@chromium.org>"); | |
517 | MODULE_DESCRIPTION("pstore backend for block devices"); |