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04851772 MF |
1 | #include <linux/efi.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/pstore.h> | |
20b4fb48 | 4 | #include <linux/slab.h> |
a614e192 | 5 | #include <linux/ucs2_string.h> |
04851772 MF |
6 | |
7 | #define DUMP_NAME_LEN 52 | |
8 | ||
9 | static bool efivars_pstore_disable = | |
10 | IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE); | |
11 | ||
12 | module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644); | |
13 | ||
14 | #define PSTORE_EFI_ATTRIBUTES \ | |
15 | (EFI_VARIABLE_NON_VOLATILE | \ | |
16 | EFI_VARIABLE_BOOTSERVICE_ACCESS | \ | |
17 | EFI_VARIABLE_RUNTIME_ACCESS) | |
18 | ||
19 | static int efi_pstore_open(struct pstore_info *psi) | |
20 | { | |
04851772 MF |
21 | psi->data = NULL; |
22 | return 0; | |
23 | } | |
24 | ||
25 | static int efi_pstore_close(struct pstore_info *psi) | |
26 | { | |
04851772 MF |
27 | psi->data = NULL; |
28 | return 0; | |
29 | } | |
30 | ||
31 | struct pstore_read_data { | |
32 | u64 *id; | |
33 | enum pstore_type_id *type; | |
34 | int *count; | |
35 | struct timespec *timespec; | |
f8c62f34 | 36 | bool *compressed; |
04851772 MF |
37 | char **buf; |
38 | }; | |
39 | ||
fdeadb43 MX |
40 | static inline u64 generic_id(unsigned long timestamp, |
41 | unsigned int part, int count) | |
42 | { | |
43 | return (timestamp * 100 + part) * 1000 + count; | |
44 | } | |
45 | ||
04851772 MF |
46 | static int efi_pstore_read_func(struct efivar_entry *entry, void *data) |
47 | { | |
48 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
49 | struct pstore_read_data *cb_data = data; | |
f8c62f34 | 50 | char name[DUMP_NAME_LEN], data_type; |
04851772 MF |
51 | int i; |
52 | int cnt; | |
53 | unsigned int part; | |
54 | unsigned long time, size; | |
55 | ||
56 | if (efi_guidcmp(entry->var.VendorGuid, vendor)) | |
57 | return 0; | |
58 | ||
59 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
60 | name[i] = entry->var.VariableName[i]; | |
61 | ||
f8c62f34 AB |
62 | if (sscanf(name, "dump-type%u-%u-%d-%lu-%c", |
63 | cb_data->type, &part, &cnt, &time, &data_type) == 5) { | |
fdeadb43 | 64 | *cb_data->id = generic_id(time, part, cnt); |
f8c62f34 AB |
65 | *cb_data->count = cnt; |
66 | cb_data->timespec->tv_sec = time; | |
67 | cb_data->timespec->tv_nsec = 0; | |
68 | if (data_type == 'C') | |
69 | *cb_data->compressed = true; | |
70 | else | |
71 | *cb_data->compressed = false; | |
72 | } else if (sscanf(name, "dump-type%u-%u-%d-%lu", | |
04851772 | 73 | cb_data->type, &part, &cnt, &time) == 4) { |
fdeadb43 | 74 | *cb_data->id = generic_id(time, part, cnt); |
04851772 MF |
75 | *cb_data->count = cnt; |
76 | cb_data->timespec->tv_sec = time; | |
77 | cb_data->timespec->tv_nsec = 0; | |
f8c62f34 | 78 | *cb_data->compressed = false; |
04851772 MF |
79 | } else if (sscanf(name, "dump-type%u-%u-%lu", |
80 | cb_data->type, &part, &time) == 3) { | |
81 | /* | |
82 | * Check if an old format, | |
83 | * which doesn't support holding | |
84 | * multiple logs, remains. | |
85 | */ | |
fdeadb43 | 86 | *cb_data->id = generic_id(time, part, 0); |
04851772 MF |
87 | *cb_data->count = 0; |
88 | cb_data->timespec->tv_sec = time; | |
89 | cb_data->timespec->tv_nsec = 0; | |
f8c62f34 | 90 | *cb_data->compressed = false; |
04851772 MF |
91 | } else |
92 | return 0; | |
93 | ||
8a415b8c MF |
94 | entry->var.DataSize = 1024; |
95 | __efivar_entry_get(entry, &entry->var.Attributes, | |
96 | &entry->var.DataSize, entry->var.Data); | |
97 | size = entry->var.DataSize; | |
e0d59733 SA |
98 | memcpy(*cb_data->buf, entry->var.Data, |
99 | (size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX, size)); | |
8a415b8c | 100 | |
04851772 MF |
101 | return size; |
102 | } | |
103 | ||
e0d59733 SA |
104 | /** |
105 | * efi_pstore_scan_sysfs_enter | |
106 | * @entry: scanning entry | |
107 | * @next: next entry | |
108 | * @head: list head | |
109 | */ | |
110 | static void efi_pstore_scan_sysfs_enter(struct efivar_entry *pos, | |
111 | struct efivar_entry *next, | |
112 | struct list_head *head) | |
113 | { | |
114 | pos->scanning = true; | |
115 | if (&next->list != head) | |
116 | next->scanning = true; | |
117 | } | |
118 | ||
119 | /** | |
120 | * __efi_pstore_scan_sysfs_exit | |
121 | * @entry: deleting entry | |
122 | * @turn_off_scanning: Check if a scanning flag should be turned off | |
123 | */ | |
124 | static inline void __efi_pstore_scan_sysfs_exit(struct efivar_entry *entry, | |
125 | bool turn_off_scanning) | |
126 | { | |
127 | if (entry->deleting) { | |
128 | list_del(&entry->list); | |
129 | efivar_entry_iter_end(); | |
130 | efivar_unregister(entry); | |
131 | efivar_entry_iter_begin(); | |
132 | } else if (turn_off_scanning) | |
133 | entry->scanning = false; | |
134 | } | |
135 | ||
136 | /** | |
137 | * efi_pstore_scan_sysfs_exit | |
138 | * @pos: scanning entry | |
139 | * @next: next entry | |
140 | * @head: list head | |
141 | * @stop: a flag checking if scanning will stop | |
142 | */ | |
143 | static void efi_pstore_scan_sysfs_exit(struct efivar_entry *pos, | |
144 | struct efivar_entry *next, | |
145 | struct list_head *head, bool stop) | |
146 | { | |
147 | __efi_pstore_scan_sysfs_exit(pos, true); | |
148 | if (stop) | |
149 | __efi_pstore_scan_sysfs_exit(next, &next->list != head); | |
150 | } | |
151 | ||
152 | /** | |
153 | * efi_pstore_sysfs_entry_iter | |
154 | * | |
155 | * @data: function-specific data to pass to callback | |
156 | * @pos: entry to begin iterating from | |
157 | * | |
158 | * You MUST call efivar_enter_iter_begin() before this function, and | |
159 | * efivar_entry_iter_end() afterwards. | |
160 | * | |
161 | * It is possible to begin iteration from an arbitrary entry within | |
162 | * the list by passing @pos. @pos is updated on return to point to | |
163 | * the next entry of the last one passed to efi_pstore_read_func(). | |
164 | * To begin iterating from the beginning of the list @pos must be %NULL. | |
165 | */ | |
166 | static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos) | |
167 | { | |
168 | struct efivar_entry *entry, *n; | |
169 | struct list_head *head = &efivar_sysfs_list; | |
170 | int size = 0; | |
171 | ||
172 | if (!*pos) { | |
173 | list_for_each_entry_safe(entry, n, head, list) { | |
174 | efi_pstore_scan_sysfs_enter(entry, n, head); | |
175 | ||
176 | size = efi_pstore_read_func(entry, data); | |
177 | efi_pstore_scan_sysfs_exit(entry, n, head, size < 0); | |
178 | if (size) | |
179 | break; | |
180 | } | |
181 | *pos = n; | |
182 | return size; | |
183 | } | |
184 | ||
185 | list_for_each_entry_safe_from((*pos), n, head, list) { | |
186 | efi_pstore_scan_sysfs_enter((*pos), n, head); | |
187 | ||
188 | size = efi_pstore_read_func((*pos), data); | |
189 | efi_pstore_scan_sysfs_exit((*pos), n, head, size < 0); | |
190 | if (size) | |
191 | break; | |
192 | } | |
193 | *pos = n; | |
194 | return size; | |
195 | } | |
196 | ||
197 | /** | |
198 | * efi_pstore_read | |
199 | * | |
200 | * This function returns a size of NVRAM entry logged via efi_pstore_write(). | |
201 | * The meaning and behavior of efi_pstore/pstore are as below. | |
202 | * | |
203 | * size > 0: Got data of an entry logged via efi_pstore_write() successfully, | |
204 | * and pstore filesystem will continue reading subsequent entries. | |
205 | * size == 0: Entry was not logged via efi_pstore_write(), | |
206 | * and efi_pstore driver will continue reading subsequent entries. | |
207 | * size < 0: Failed to get data of entry logging via efi_pstore_write(), | |
208 | * and pstore will stop reading entry. | |
209 | */ | |
04851772 MF |
210 | static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, |
211 | int *count, struct timespec *timespec, | |
9a4e1398 AB |
212 | char **buf, bool *compressed, |
213 | struct pstore_info *psi) | |
04851772 MF |
214 | { |
215 | struct pstore_read_data data; | |
e0d59733 | 216 | ssize_t size; |
04851772 MF |
217 | |
218 | data.id = id; | |
219 | data.type = type; | |
220 | data.count = count; | |
221 | data.timespec = timespec; | |
f8c62f34 | 222 | data.compressed = compressed; |
04851772 MF |
223 | data.buf = buf; |
224 | ||
e0d59733 SA |
225 | *data.buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL); |
226 | if (!*data.buf) | |
227 | return -ENOMEM; | |
228 | ||
229 | efivar_entry_iter_begin(); | |
230 | size = efi_pstore_sysfs_entry_iter(&data, | |
231 | (struct efivar_entry **)&psi->data); | |
232 | efivar_entry_iter_end(); | |
233 | if (size <= 0) | |
234 | kfree(*data.buf); | |
235 | return size; | |
04851772 MF |
236 | } |
237 | ||
238 | static int efi_pstore_write(enum pstore_type_id type, | |
239 | enum kmsg_dump_reason reason, u64 *id, | |
b3b515bb | 240 | unsigned int part, int count, bool compressed, size_t size, |
04851772 MF |
241 | struct pstore_info *psi) |
242 | { | |
243 | char name[DUMP_NAME_LEN]; | |
244 | efi_char16_t efi_name[DUMP_NAME_LEN]; | |
245 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
246 | int i, ret = 0; | |
247 | ||
f8c62f34 AB |
248 | sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count, |
249 | get_seconds(), compressed ? 'C' : 'D'); | |
04851772 MF |
250 | |
251 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
252 | efi_name[i] = name[i]; | |
253 | ||
254 | efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES, | |
255 | !pstore_cannot_block_path(reason), | |
256 | size, psi->buf); | |
257 | ||
258 | if (reason == KMSG_DUMP_OOPS) | |
259 | efivar_run_worker(); | |
260 | ||
261 | *id = part; | |
262 | return ret; | |
263 | }; | |
264 | ||
265 | struct pstore_erase_data { | |
266 | u64 id; | |
267 | enum pstore_type_id type; | |
268 | int count; | |
269 | struct timespec time; | |
270 | efi_char16_t *name; | |
271 | }; | |
272 | ||
273 | /* | |
274 | * Clean up an entry with the same name | |
275 | */ | |
276 | static int efi_pstore_erase_func(struct efivar_entry *entry, void *data) | |
277 | { | |
278 | struct pstore_erase_data *ed = data; | |
279 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
280 | efi_char16_t efi_name_old[DUMP_NAME_LEN]; | |
281 | efi_char16_t *efi_name = ed->name; | |
a614e192 | 282 | unsigned long ucs2_len = ucs2_strlen(ed->name); |
04851772 MF |
283 | char name_old[DUMP_NAME_LEN]; |
284 | int i; | |
285 | ||
286 | if (efi_guidcmp(entry->var.VendorGuid, vendor)) | |
287 | return 0; | |
288 | ||
a614e192 MF |
289 | if (ucs2_strncmp(entry->var.VariableName, |
290 | efi_name, (size_t)ucs2_len)) { | |
04851772 MF |
291 | /* |
292 | * Check if an old format, which doesn't support | |
293 | * holding multiple logs, remains. | |
294 | */ | |
295 | sprintf(name_old, "dump-type%u-%u-%lu", ed->type, | |
296 | (unsigned int)ed->id, ed->time.tv_sec); | |
297 | ||
298 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
299 | efi_name_old[i] = name_old[i]; | |
300 | ||
a614e192 MF |
301 | if (ucs2_strncmp(entry->var.VariableName, efi_name_old, |
302 | ucs2_strlen(efi_name_old))) | |
04851772 MF |
303 | return 0; |
304 | } | |
305 | ||
e0d59733 SA |
306 | if (entry->scanning) { |
307 | /* | |
308 | * Skip deletion because this entry will be deleted | |
309 | * after scanning is completed. | |
310 | */ | |
311 | entry->deleting = true; | |
312 | } else | |
313 | list_del(&entry->list); | |
314 | ||
04851772 MF |
315 | /* found */ |
316 | __efivar_entry_delete(entry); | |
12abcfde | 317 | |
04851772 MF |
318 | return 1; |
319 | } | |
320 | ||
321 | static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, | |
322 | struct timespec time, struct pstore_info *psi) | |
323 | { | |
324 | struct pstore_erase_data edata; | |
4ee39e97 | 325 | struct efivar_entry *entry = NULL; |
04851772 MF |
326 | char name[DUMP_NAME_LEN]; |
327 | efi_char16_t efi_name[DUMP_NAME_LEN]; | |
328 | int found, i; | |
fdeadb43 | 329 | unsigned int part; |
04851772 | 330 | |
fdeadb43 MX |
331 | do_div(id, 1000); |
332 | part = do_div(id, 100); | |
333 | sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, time.tv_sec); | |
04851772 MF |
334 | |
335 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
336 | efi_name[i] = name[i]; | |
337 | ||
fdeadb43 | 338 | edata.id = part; |
04851772 MF |
339 | edata.type = type; |
340 | edata.count = count; | |
341 | edata.time = time; | |
342 | edata.name = efi_name; | |
343 | ||
344 | efivar_entry_iter_begin(); | |
345 | found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry); | |
04851772 | 346 | |
e0d59733 SA |
347 | if (found && !entry->scanning) { |
348 | efivar_entry_iter_end(); | |
04851772 | 349 | efivar_unregister(entry); |
e0d59733 SA |
350 | } else |
351 | efivar_entry_iter_end(); | |
04851772 MF |
352 | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static struct pstore_info efi_pstore_info = { | |
357 | .owner = THIS_MODULE, | |
358 | .name = "efi", | |
df36ac1b | 359 | .flags = PSTORE_FLAGS_FRAGILE, |
04851772 MF |
360 | .open = efi_pstore_open, |
361 | .close = efi_pstore_close, | |
362 | .read = efi_pstore_read, | |
363 | .write = efi_pstore_write, | |
364 | .erase = efi_pstore_erase, | |
365 | }; | |
366 | ||
367 | static __init int efivars_pstore_init(void) | |
368 | { | |
369 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
370 | return 0; | |
371 | ||
372 | if (!efivars_kobject()) | |
373 | return 0; | |
374 | ||
375 | if (efivars_pstore_disable) | |
376 | return 0; | |
377 | ||
378 | efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); | |
379 | if (!efi_pstore_info.buf) | |
380 | return -ENOMEM; | |
381 | ||
382 | efi_pstore_info.bufsize = 1024; | |
383 | spin_lock_init(&efi_pstore_info.buf_lock); | |
384 | ||
0d838347 LS |
385 | if (pstore_register(&efi_pstore_info)) { |
386 | kfree(efi_pstore_info.buf); | |
387 | efi_pstore_info.buf = NULL; | |
388 | efi_pstore_info.bufsize = 0; | |
389 | } | |
04851772 MF |
390 | |
391 | return 0; | |
392 | } | |
393 | ||
394 | static __exit void efivars_pstore_exit(void) | |
395 | { | |
396 | } | |
397 | ||
398 | module_init(efivars_pstore_init); | |
399 | module_exit(efivars_pstore_exit); | |
400 | ||
401 | MODULE_DESCRIPTION("EFI variable backend for pstore"); | |
402 | MODULE_LICENSE("GPL"); |