2 #include <linux/module.h>
3 #include <linux/pstore.h>
4 #include <linux/ucs2_string.h>
6 #define DUMP_NAME_LEN 52
8 static bool efivars_pstore_disable =
9 IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE);
11 module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
13 #define PSTORE_EFI_ATTRIBUTES \
14 (EFI_VARIABLE_NON_VOLATILE | \
15 EFI_VARIABLE_BOOTSERVICE_ACCESS | \
16 EFI_VARIABLE_RUNTIME_ACCESS)
18 static int efi_pstore_open(struct pstore_info *psi)
20 efivar_entry_iter_begin();
25 static int efi_pstore_close(struct pstore_info *psi)
27 efivar_entry_iter_end();
32 struct pstore_read_data {
34 enum pstore_type_id *type;
36 struct timespec *timespec;
40 static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
42 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
43 struct pstore_read_data *cb_data = data;
44 char name[DUMP_NAME_LEN];
48 unsigned long time, size;
50 if (efi_guidcmp(entry->var.VendorGuid, vendor))
53 for (i = 0; i < DUMP_NAME_LEN; i++)
54 name[i] = entry->var.VariableName[i];
56 if (sscanf(name, "dump-type%u-%u-%d-%lu",
57 cb_data->type, &part, &cnt, &time) == 4) {
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) {
65 * Check if an old format,
66 * which doesn't support holding
67 * multiple logs, remains.
71 cb_data->timespec->tv_sec = time;
72 cb_data->timespec->tv_nsec = 0;
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;
81 *cb_data->buf = kmalloc(size, GFP_KERNEL);
82 if (*cb_data->buf == NULL)
84 memcpy(*cb_data->buf, entry->var.Data, size);
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)
92 struct pstore_read_data data;
97 data.timespec = timespec;
100 return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
101 (struct efivar_entry **)&psi->data);
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)
109 char name[DUMP_NAME_LEN];
110 efi_char16_t efi_name[DUMP_NAME_LEN];
111 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
114 sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
117 for (i = 0; i < DUMP_NAME_LEN; i++)
118 efi_name[i] = name[i];
120 efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
121 !pstore_cannot_block_path(reason),
124 if (reason == KMSG_DUMP_OOPS)
131 struct pstore_erase_data {
133 enum pstore_type_id type;
135 struct timespec time;
140 * Clean up an entry with the same name
142 static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
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;
148 unsigned long ucs2_len = ucs2_strlen(ed->name);
149 char name_old[DUMP_NAME_LEN];
152 if (efi_guidcmp(entry->var.VendorGuid, vendor))
155 if (ucs2_strncmp(entry->var.VariableName,
156 efi_name, (size_t)ucs2_len)) {
158 * Check if an old format, which doesn't support
159 * holding multiple logs, remains.
161 sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
162 (unsigned int)ed->id, ed->time.tv_sec);
164 for (i = 0; i < DUMP_NAME_LEN; i++)
165 efi_name_old[i] = name_old[i];
167 if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
168 ucs2_strlen(efi_name_old)))
173 __efivar_entry_delete(entry);
174 list_del(&entry->list);
179 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
180 struct timespec time, struct pstore_info *psi)
182 struct pstore_erase_data edata;
183 struct efivar_entry *entry = NULL;
184 char name[DUMP_NAME_LEN];
185 efi_char16_t efi_name[DUMP_NAME_LEN];
188 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
191 for (i = 0; i < DUMP_NAME_LEN; i++)
192 efi_name[i] = name[i];
198 edata.name = efi_name;
200 efivar_entry_iter_begin();
201 found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
202 efivar_entry_iter_end();
205 efivar_unregister(entry);
210 static struct pstore_info efi_pstore_info = {
211 .owner = THIS_MODULE,
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,
220 static __init int efivars_pstore_init(void)
222 if (!efi_enabled(EFI_RUNTIME_SERVICES))
225 if (!efivars_kobject())
228 if (efivars_pstore_disable)
231 efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
232 if (!efi_pstore_info.buf)
235 efi_pstore_info.bufsize = 1024;
236 spin_lock_init(&efi_pstore_info.buf_lock);
238 pstore_register(&efi_pstore_info);
243 static __exit void efivars_pstore_exit(void)
247 module_init(efivars_pstore_init);
248 module_exit(efivars_pstore_exit);
250 MODULE_DESCRIPTION("EFI variable backend for pstore");
251 MODULE_LICENSE("GPL");