2 #include <linux/module.h>
3 #include <linux/pstore.h>
4 #include <linux/slab.h>
5 #include <linux/ucs2_string.h>
7 #define DUMP_NAME_LEN 52
9 static bool efivars_pstore_disable
=
10 IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE
);
12 module_param_named(pstore_disable
, efivars_pstore_disable
, bool, 0644);
14 #define PSTORE_EFI_ATTRIBUTES \
15 (EFI_VARIABLE_NON_VOLATILE | \
16 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
17 EFI_VARIABLE_RUNTIME_ACCESS)
19 static int efi_pstore_open(struct pstore_info
*psi
)
25 static int efi_pstore_close(struct pstore_info
*psi
)
31 static inline u64
generic_id(unsigned long timestamp
,
32 unsigned int part
, int count
)
34 return ((u64
) timestamp
* 100 + part
) * 1000 + count
;
37 static int efi_pstore_read_func(struct efivar_entry
*entry
,
38 struct pstore_record
*record
)
40 efi_guid_t vendor
= LINUX_EFI_CRASH_GUID
;
41 char name
[DUMP_NAME_LEN
], data_type
;
45 unsigned long time
, size
;
47 if (efi_guidcmp(entry
->var
.VendorGuid
, vendor
))
50 for (i
= 0; i
< DUMP_NAME_LEN
; i
++)
51 name
[i
] = entry
->var
.VariableName
[i
];
53 if (sscanf(name
, "dump-type%u-%u-%d-%lu-%c",
54 &record
->type
, &part
, &cnt
, &time
, &data_type
) == 5) {
55 record
->id
= generic_id(time
, part
, cnt
);
57 record
->time
.tv_sec
= time
;
58 record
->time
.tv_nsec
= 0;
60 record
->compressed
= true;
62 record
->compressed
= false;
63 record
->ecc_notice_size
= 0;
64 } else if (sscanf(name
, "dump-type%u-%u-%d-%lu",
65 &record
->type
, &part
, &cnt
, &time
) == 4) {
66 record
->id
= generic_id(time
, part
, cnt
);
68 record
->time
.tv_sec
= time
;
69 record
->time
.tv_nsec
= 0;
70 record
->compressed
= false;
71 record
->ecc_notice_size
= 0;
72 } else if (sscanf(name
, "dump-type%u-%u-%lu",
73 &record
->type
, &part
, &time
) == 3) {
75 * Check if an old format,
76 * which doesn't support holding
77 * multiple logs, remains.
79 record
->id
= generic_id(time
, part
, 0);
81 record
->time
.tv_sec
= time
;
82 record
->time
.tv_nsec
= 0;
83 record
->compressed
= false;
84 record
->ecc_notice_size
= 0;
88 entry
->var
.DataSize
= 1024;
89 __efivar_entry_get(entry
, &entry
->var
.Attributes
,
90 &entry
->var
.DataSize
, entry
->var
.Data
);
91 size
= entry
->var
.DataSize
;
92 memcpy(record
->buf
, entry
->var
.Data
,
93 (size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX
, size
));
99 * efi_pstore_scan_sysfs_enter
100 * @pos: scanning entry
104 static void efi_pstore_scan_sysfs_enter(struct efivar_entry
*pos
,
105 struct efivar_entry
*next
,
106 struct list_head
*head
)
108 pos
->scanning
= true;
109 if (&next
->list
!= head
)
110 next
->scanning
= true;
114 * __efi_pstore_scan_sysfs_exit
115 * @entry: deleting entry
116 * @turn_off_scanning: Check if a scanning flag should be turned off
118 static inline int __efi_pstore_scan_sysfs_exit(struct efivar_entry
*entry
,
119 bool turn_off_scanning
)
121 if (entry
->deleting
) {
122 list_del(&entry
->list
);
123 efivar_entry_iter_end();
124 efivar_unregister(entry
);
125 if (efivar_entry_iter_begin())
127 } else if (turn_off_scanning
)
128 entry
->scanning
= false;
134 * efi_pstore_scan_sysfs_exit
135 * @pos: scanning entry
138 * @stop: a flag checking if scanning will stop
140 static int efi_pstore_scan_sysfs_exit(struct efivar_entry
*pos
,
141 struct efivar_entry
*next
,
142 struct list_head
*head
, bool stop
)
144 int ret
= __efi_pstore_scan_sysfs_exit(pos
, true);
150 ret
= __efi_pstore_scan_sysfs_exit(next
, &next
->list
!= head
);
155 * efi_pstore_sysfs_entry_iter
157 * @record: pstore record to pass to callback
159 * You MUST call efivar_enter_iter_begin() before this function, and
160 * efivar_entry_iter_end() afterwards.
163 static int efi_pstore_sysfs_entry_iter(struct pstore_record
*record
)
165 struct efivar_entry
**pos
= (struct efivar_entry
**)&record
->psi
->data
;
166 struct efivar_entry
*entry
, *n
;
167 struct list_head
*head
= &efivar_sysfs_list
;
172 list_for_each_entry_safe(entry
, n
, head
, list
) {
173 efi_pstore_scan_sysfs_enter(entry
, n
, head
);
175 size
= efi_pstore_read_func(entry
, record
);
176 ret
= efi_pstore_scan_sysfs_exit(entry
, n
, head
,
187 list_for_each_entry_safe_from((*pos
), n
, head
, list
) {
188 efi_pstore_scan_sysfs_enter((*pos
), n
, head
);
190 size
= efi_pstore_read_func((*pos
), record
);
191 ret
= efi_pstore_scan_sysfs_exit((*pos
), n
, head
, size
< 0);
204 * This function returns a size of NVRAM entry logged via efi_pstore_write().
205 * The meaning and behavior of efi_pstore/pstore are as below.
207 * size > 0: Got data of an entry logged via efi_pstore_write() successfully,
208 * and pstore filesystem will continue reading subsequent entries.
209 * size == 0: Entry was not logged via efi_pstore_write(),
210 * and efi_pstore driver will continue reading subsequent entries.
211 * size < 0: Failed to get data of entry logging via efi_pstore_write(),
212 * and pstore will stop reading entry.
214 static ssize_t
efi_pstore_read(struct pstore_record
*record
)
218 record
->buf
= kzalloc(EFIVARS_DATA_SIZE_MAX
, GFP_KERNEL
);
222 if (efivar_entry_iter_begin()) {
226 size
= efi_pstore_sysfs_entry_iter(record
);
227 efivar_entry_iter_end();
237 static int efi_pstore_write(struct pstore_record
*record
)
239 char name
[DUMP_NAME_LEN
];
240 efi_char16_t efi_name
[DUMP_NAME_LEN
];
241 efi_guid_t vendor
= LINUX_EFI_CRASH_GUID
;
244 snprintf(name
, sizeof(name
), "dump-type%u-%u-%d-%lu-%c",
245 record
->type
, record
->part
, record
->count
,
246 get_seconds(), record
->compressed
? 'C' : 'D');
248 for (i
= 0; i
< DUMP_NAME_LEN
; i
++)
249 efi_name
[i
] = name
[i
];
251 ret
= efivar_entry_set_safe(efi_name
, vendor
, PSTORE_EFI_ATTRIBUTES
,
252 !pstore_cannot_block_path(record
->reason
),
253 record
->size
, record
->psi
->buf
);
255 if (record
->reason
== KMSG_DUMP_OOPS
)
258 record
->id
= record
->part
;
262 struct pstore_erase_data
{
263 struct pstore_record
*record
;
268 * Clean up an entry with the same name
270 static int efi_pstore_erase_func(struct efivar_entry
*entry
, void *data
)
272 struct pstore_erase_data
*ed
= data
;
273 efi_guid_t vendor
= LINUX_EFI_CRASH_GUID
;
274 efi_char16_t efi_name_old
[DUMP_NAME_LEN
];
275 efi_char16_t
*efi_name
= ed
->name
;
276 unsigned long ucs2_len
= ucs2_strlen(ed
->name
);
277 char name_old
[DUMP_NAME_LEN
];
280 if (efi_guidcmp(entry
->var
.VendorGuid
, vendor
))
283 if (ucs2_strncmp(entry
->var
.VariableName
,
284 efi_name
, (size_t)ucs2_len
)) {
286 * Check if an old format, which doesn't support
287 * holding multiple logs, remains.
289 snprintf(name_old
, sizeof(name_old
), "dump-type%u-%u-%lu",
290 ed
->record
->type
, (unsigned int)ed
->record
->id
,
291 ed
->record
->time
.tv_sec
);
293 for (i
= 0; i
< DUMP_NAME_LEN
; i
++)
294 efi_name_old
[i
] = name_old
[i
];
296 if (ucs2_strncmp(entry
->var
.VariableName
, efi_name_old
,
297 ucs2_strlen(efi_name_old
)))
301 if (entry
->scanning
) {
303 * Skip deletion because this entry will be deleted
304 * after scanning is completed.
306 entry
->deleting
= true;
308 list_del(&entry
->list
);
311 __efivar_entry_delete(entry
);
316 static int efi_pstore_erase(struct pstore_record
*record
)
318 struct pstore_erase_data edata
;
319 struct efivar_entry
*entry
= NULL
;
320 char name
[DUMP_NAME_LEN
];
321 efi_char16_t efi_name
[DUMP_NAME_LEN
];
325 do_div(record
->id
, 1000);
326 part
= do_div(record
->id
, 100);
327 snprintf(name
, sizeof(name
), "dump-type%u-%u-%d-%lu",
328 record
->type
, record
->part
, record
->count
,
329 record
->time
.tv_sec
);
331 for (i
= 0; i
< DUMP_NAME_LEN
; i
++)
332 efi_name
[i
] = name
[i
];
334 edata
.record
= record
;
335 edata
.name
= efi_name
;
337 if (efivar_entry_iter_begin())
339 found
= __efivar_entry_iter(efi_pstore_erase_func
, &efivar_sysfs_list
, &edata
, &entry
);
341 if (found
&& !entry
->scanning
) {
342 efivar_entry_iter_end();
343 efivar_unregister(entry
);
345 efivar_entry_iter_end();
350 static struct pstore_info efi_pstore_info
= {
351 .owner
= THIS_MODULE
,
353 .flags
= PSTORE_FLAGS_DMESG
,
354 .open
= efi_pstore_open
,
355 .close
= efi_pstore_close
,
356 .read
= efi_pstore_read
,
357 .write
= efi_pstore_write
,
358 .erase
= efi_pstore_erase
,
361 static __init
int efivars_pstore_init(void)
363 if (!efi_enabled(EFI_RUNTIME_SERVICES
))
366 if (!efivars_kobject())
369 if (efivars_pstore_disable
)
372 efi_pstore_info
.buf
= kmalloc(4096, GFP_KERNEL
);
373 if (!efi_pstore_info
.buf
)
376 efi_pstore_info
.bufsize
= 1024;
377 spin_lock_init(&efi_pstore_info
.buf_lock
);
379 if (pstore_register(&efi_pstore_info
)) {
380 kfree(efi_pstore_info
.buf
);
381 efi_pstore_info
.buf
= NULL
;
382 efi_pstore_info
.bufsize
= 0;
388 static __exit
void efivars_pstore_exit(void)
390 if (!efi_pstore_info
.bufsize
)
393 pstore_unregister(&efi_pstore_info
);
394 kfree(efi_pstore_info
.buf
);
395 efi_pstore_info
.buf
= NULL
;
396 efi_pstore_info
.bufsize
= 0;
399 module_init(efivars_pstore_init
);
400 module_exit(efivars_pstore_exit
);
402 MODULE_DESCRIPTION("EFI variable backend for pstore");
403 MODULE_LICENSE("GPL");
404 MODULE_ALIAS("platform:efivars");