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04851772 MF |
1 | #include <linux/efi.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/pstore.h> | |
a614e192 | 4 | #include <linux/ucs2_string.h> |
04851772 MF |
5 | |
6 | #define DUMP_NAME_LEN 52 | |
7 | ||
8 | static bool efivars_pstore_disable = | |
9 | IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE); | |
10 | ||
11 | module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644); | |
12 | ||
13 | #define PSTORE_EFI_ATTRIBUTES \ | |
14 | (EFI_VARIABLE_NON_VOLATILE | \ | |
15 | EFI_VARIABLE_BOOTSERVICE_ACCESS | \ | |
16 | EFI_VARIABLE_RUNTIME_ACCESS) | |
17 | ||
18 | static int efi_pstore_open(struct pstore_info *psi) | |
19 | { | |
20 | efivar_entry_iter_begin(); | |
21 | psi->data = NULL; | |
22 | return 0; | |
23 | } | |
24 | ||
25 | static int efi_pstore_close(struct pstore_info *psi) | |
26 | { | |
27 | efivar_entry_iter_end(); | |
28 | psi->data = NULL; | |
29 | return 0; | |
30 | } | |
31 | ||
32 | struct pstore_read_data { | |
33 | u64 *id; | |
34 | enum pstore_type_id *type; | |
35 | int *count; | |
36 | struct timespec *timespec; | |
37 | char **buf; | |
38 | }; | |
39 | ||
40 | static int efi_pstore_read_func(struct efivar_entry *entry, void *data) | |
41 | { | |
42 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
43 | struct pstore_read_data *cb_data = data; | |
44 | char name[DUMP_NAME_LEN]; | |
45 | int i; | |
46 | int cnt; | |
47 | unsigned int part; | |
48 | unsigned long time, size; | |
49 | ||
50 | if (efi_guidcmp(entry->var.VendorGuid, vendor)) | |
51 | return 0; | |
52 | ||
53 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
54 | name[i] = entry->var.VariableName[i]; | |
55 | ||
56 | if (sscanf(name, "dump-type%u-%u-%d-%lu", | |
57 | cb_data->type, &part, &cnt, &time) == 4) { | |
58 | *cb_data->id = part; | |
59 | *cb_data->count = cnt; | |
60 | cb_data->timespec->tv_sec = time; | |
61 | cb_data->timespec->tv_nsec = 0; | |
62 | } else if (sscanf(name, "dump-type%u-%u-%lu", | |
63 | cb_data->type, &part, &time) == 3) { | |
64 | /* | |
65 | * Check if an old format, | |
66 | * which doesn't support holding | |
67 | * multiple logs, remains. | |
68 | */ | |
69 | *cb_data->id = part; | |
70 | *cb_data->count = 0; | |
71 | cb_data->timespec->tv_sec = time; | |
72 | cb_data->timespec->tv_nsec = 0; | |
73 | } else | |
74 | return 0; | |
75 | ||
8a415b8c MF |
76 | entry->var.DataSize = 1024; |
77 | __efivar_entry_get(entry, &entry->var.Attributes, | |
78 | &entry->var.DataSize, entry->var.Data); | |
79 | size = entry->var.DataSize; | |
80 | ||
04851772 MF |
81 | *cb_data->buf = kmalloc(size, GFP_KERNEL); |
82 | if (*cb_data->buf == NULL) | |
83 | return -ENOMEM; | |
84 | memcpy(*cb_data->buf, entry->var.Data, size); | |
85 | return size; | |
86 | } | |
87 | ||
88 | static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, | |
89 | int *count, struct timespec *timespec, | |
90 | char **buf, struct pstore_info *psi) | |
91 | { | |
92 | struct pstore_read_data data; | |
93 | ||
94 | data.id = id; | |
95 | data.type = type; | |
96 | data.count = count; | |
97 | data.timespec = timespec; | |
98 | data.buf = buf; | |
99 | ||
100 | return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data, | |
101 | (struct efivar_entry **)&psi->data); | |
102 | } | |
103 | ||
104 | static int efi_pstore_write(enum pstore_type_id type, | |
105 | enum kmsg_dump_reason reason, u64 *id, | |
106 | unsigned int part, int count, size_t size, | |
107 | struct pstore_info *psi) | |
108 | { | |
109 | char name[DUMP_NAME_LEN]; | |
110 | efi_char16_t efi_name[DUMP_NAME_LEN]; | |
111 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
112 | int i, ret = 0; | |
113 | ||
114 | sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, | |
115 | get_seconds()); | |
116 | ||
117 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
118 | efi_name[i] = name[i]; | |
119 | ||
120 | efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES, | |
121 | !pstore_cannot_block_path(reason), | |
122 | size, psi->buf); | |
123 | ||
124 | if (reason == KMSG_DUMP_OOPS) | |
125 | efivar_run_worker(); | |
126 | ||
127 | *id = part; | |
128 | return ret; | |
129 | }; | |
130 | ||
131 | struct pstore_erase_data { | |
132 | u64 id; | |
133 | enum pstore_type_id type; | |
134 | int count; | |
135 | struct timespec time; | |
136 | efi_char16_t *name; | |
137 | }; | |
138 | ||
139 | /* | |
140 | * Clean up an entry with the same name | |
141 | */ | |
142 | static int efi_pstore_erase_func(struct efivar_entry *entry, void *data) | |
143 | { | |
144 | struct pstore_erase_data *ed = data; | |
145 | efi_guid_t vendor = LINUX_EFI_CRASH_GUID; | |
146 | efi_char16_t efi_name_old[DUMP_NAME_LEN]; | |
147 | efi_char16_t *efi_name = ed->name; | |
a614e192 | 148 | unsigned long ucs2_len = ucs2_strlen(ed->name); |
04851772 MF |
149 | char name_old[DUMP_NAME_LEN]; |
150 | int i; | |
151 | ||
152 | if (efi_guidcmp(entry->var.VendorGuid, vendor)) | |
153 | return 0; | |
154 | ||
a614e192 MF |
155 | if (ucs2_strncmp(entry->var.VariableName, |
156 | efi_name, (size_t)ucs2_len)) { | |
04851772 MF |
157 | /* |
158 | * Check if an old format, which doesn't support | |
159 | * holding multiple logs, remains. | |
160 | */ | |
161 | sprintf(name_old, "dump-type%u-%u-%lu", ed->type, | |
162 | (unsigned int)ed->id, ed->time.tv_sec); | |
163 | ||
164 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
165 | efi_name_old[i] = name_old[i]; | |
166 | ||
a614e192 MF |
167 | if (ucs2_strncmp(entry->var.VariableName, efi_name_old, |
168 | ucs2_strlen(efi_name_old))) | |
04851772 MF |
169 | return 0; |
170 | } | |
171 | ||
172 | /* found */ | |
173 | __efivar_entry_delete(entry); | |
12abcfde MF |
174 | list_del(&entry->list); |
175 | ||
04851772 MF |
176 | return 1; |
177 | } | |
178 | ||
179 | static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, | |
180 | struct timespec time, struct pstore_info *psi) | |
181 | { | |
182 | struct pstore_erase_data edata; | |
4ee39e97 | 183 | struct efivar_entry *entry = NULL; |
04851772 MF |
184 | char name[DUMP_NAME_LEN]; |
185 | efi_char16_t efi_name[DUMP_NAME_LEN]; | |
186 | int found, i; | |
187 | ||
188 | sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count, | |
189 | time.tv_sec); | |
190 | ||
191 | for (i = 0; i < DUMP_NAME_LEN; i++) | |
192 | efi_name[i] = name[i]; | |
193 | ||
194 | edata.id = id; | |
195 | edata.type = type; | |
196 | edata.count = count; | |
197 | edata.time = time; | |
198 | edata.name = efi_name; | |
199 | ||
200 | efivar_entry_iter_begin(); | |
201 | found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry); | |
202 | efivar_entry_iter_end(); | |
203 | ||
204 | if (found) | |
205 | efivar_unregister(entry); | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | static struct pstore_info efi_pstore_info = { | |
211 | .owner = THIS_MODULE, | |
212 | .name = "efi", | |
213 | .open = efi_pstore_open, | |
214 | .close = efi_pstore_close, | |
215 | .read = efi_pstore_read, | |
216 | .write = efi_pstore_write, | |
217 | .erase = efi_pstore_erase, | |
218 | }; | |
219 | ||
220 | static __init int efivars_pstore_init(void) | |
221 | { | |
222 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
223 | return 0; | |
224 | ||
225 | if (!efivars_kobject()) | |
226 | return 0; | |
227 | ||
228 | if (efivars_pstore_disable) | |
229 | return 0; | |
230 | ||
231 | efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); | |
232 | if (!efi_pstore_info.buf) | |
233 | return -ENOMEM; | |
234 | ||
235 | efi_pstore_info.bufsize = 1024; | |
236 | spin_lock_init(&efi_pstore_info.buf_lock); | |
237 | ||
238 | pstore_register(&efi_pstore_info); | |
239 | ||
240 | return 0; | |
241 | } | |
242 | ||
243 | static __exit void efivars_pstore_exit(void) | |
244 | { | |
245 | } | |
246 | ||
247 | module_init(efivars_pstore_init); | |
248 | module_exit(efivars_pstore_exit); | |
249 | ||
250 | MODULE_DESCRIPTION("EFI variable backend for pstore"); | |
251 | MODULE_LICENSE("GPL"); |