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)
21 efivar_entry_iter_begin();
26 static int efi_pstore_close(struct pstore_info *psi)
28 efivar_entry_iter_end();
33 struct pstore_read_data {
35 enum pstore_type_id *type;
37 struct timespec *timespec;
42 static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
44 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
45 struct pstore_read_data *cb_data = data;
46 char name[DUMP_NAME_LEN], data_type;
50 unsigned long time, size;
52 if (efi_guidcmp(entry->var.VendorGuid, vendor))
55 for (i = 0; i < DUMP_NAME_LEN; i++)
56 name[i] = entry->var.VariableName[i];
58 if (sscanf(name, "dump-type%u-%u-%d-%lu-%c",
59 cb_data->type, &part, &cnt, &time, &data_type) == 5) {
61 *cb_data->count = cnt;
62 cb_data->timespec->tv_sec = time;
63 cb_data->timespec->tv_nsec = 0;
65 *cb_data->compressed = true;
67 *cb_data->compressed = false;
68 } else if (sscanf(name, "dump-type%u-%u-%d-%lu",
69 cb_data->type, &part, &cnt, &time) == 4) {
71 *cb_data->count = cnt;
72 cb_data->timespec->tv_sec = time;
73 cb_data->timespec->tv_nsec = 0;
74 *cb_data->compressed = false;
75 } else if (sscanf(name, "dump-type%u-%u-%lu",
76 cb_data->type, &part, &time) == 3) {
78 * Check if an old format,
79 * which doesn't support holding
80 * multiple logs, remains.
84 cb_data->timespec->tv_sec = time;
85 cb_data->timespec->tv_nsec = 0;
86 *cb_data->compressed = false;
90 entry->var.DataSize = 1024;
91 __efivar_entry_get(entry, &entry->var.Attributes,
92 &entry->var.DataSize, entry->var.Data);
93 size = entry->var.DataSize;
95 *cb_data->buf = kmemdup(entry->var.Data, size, GFP_KERNEL);
96 if (*cb_data->buf == NULL)
101 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
102 int *count, struct timespec *timespec,
103 char **buf, bool *compressed,
104 struct pstore_info *psi)
106 struct pstore_read_data data;
111 data.timespec = timespec;
112 data.compressed = compressed;
115 return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
116 (struct efivar_entry **)&psi->data);
119 static int efi_pstore_write(enum pstore_type_id type,
120 enum kmsg_dump_reason reason, u64 *id,
121 unsigned int part, int count, bool compressed, size_t size,
122 struct pstore_info *psi)
124 char name[DUMP_NAME_LEN];
125 efi_char16_t efi_name[DUMP_NAME_LEN];
126 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
129 sprintf(name, "dump-type%u-%u-%d-%lu-%c", type, part, count,
130 get_seconds(), compressed ? 'C' : 'D');
132 for (i = 0; i < DUMP_NAME_LEN; i++)
133 efi_name[i] = name[i];
135 efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
136 !pstore_cannot_block_path(reason),
139 if (reason == KMSG_DUMP_OOPS)
146 struct pstore_erase_data {
148 enum pstore_type_id type;
150 struct timespec time;
155 * Clean up an entry with the same name
157 static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
159 struct pstore_erase_data *ed = data;
160 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
161 efi_char16_t efi_name_old[DUMP_NAME_LEN];
162 efi_char16_t *efi_name = ed->name;
163 unsigned long ucs2_len = ucs2_strlen(ed->name);
164 char name_old[DUMP_NAME_LEN];
167 if (efi_guidcmp(entry->var.VendorGuid, vendor))
170 if (ucs2_strncmp(entry->var.VariableName,
171 efi_name, (size_t)ucs2_len)) {
173 * Check if an old format, which doesn't support
174 * holding multiple logs, remains.
176 sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
177 (unsigned int)ed->id, ed->time.tv_sec);
179 for (i = 0; i < DUMP_NAME_LEN; i++)
180 efi_name_old[i] = name_old[i];
182 if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
183 ucs2_strlen(efi_name_old)))
188 __efivar_entry_delete(entry);
189 list_del(&entry->list);
194 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
195 struct timespec time, struct pstore_info *psi)
197 struct pstore_erase_data edata;
198 struct efivar_entry *entry = NULL;
199 char name[DUMP_NAME_LEN];
200 efi_char16_t efi_name[DUMP_NAME_LEN];
203 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
206 for (i = 0; i < DUMP_NAME_LEN; i++)
207 efi_name[i] = name[i];
213 edata.name = efi_name;
215 efivar_entry_iter_begin();
216 found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
217 efivar_entry_iter_end();
220 efivar_unregister(entry);
225 static struct pstore_info efi_pstore_info = {
226 .owner = THIS_MODULE,
228 .open = efi_pstore_open,
229 .close = efi_pstore_close,
230 .read = efi_pstore_read,
231 .write = efi_pstore_write,
232 .erase = efi_pstore_erase,
235 static __init int efivars_pstore_init(void)
237 if (!efi_enabled(EFI_RUNTIME_SERVICES))
240 if (!efivars_kobject())
243 if (efivars_pstore_disable)
246 efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
247 if (!efi_pstore_info.buf)
250 efi_pstore_info.bufsize = 1024;
251 spin_lock_init(&efi_pstore_info.buf_lock);
253 if (pstore_register(&efi_pstore_info)) {
254 kfree(efi_pstore_info.buf);
255 efi_pstore_info.buf = NULL;
256 efi_pstore_info.bufsize = 0;
262 static __exit void efivars_pstore_exit(void)
266 module_init(efivars_pstore_init);
267 module_exit(efivars_pstore_exit);
269 MODULE_DESCRIPTION("EFI variable backend for pstore");
270 MODULE_LICENSE("GPL");