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;
41 static int efi_pstore_read_func(struct efivar_entry *entry, void *data)
43 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
44 struct pstore_read_data *cb_data = data;
45 char name[DUMP_NAME_LEN];
49 unsigned long time, size;
51 if (efi_guidcmp(entry->var.VendorGuid, vendor))
54 for (i = 0; i < DUMP_NAME_LEN; i++)
55 name[i] = entry->var.VariableName[i];
57 if (sscanf(name, "dump-type%u-%u-%d-%lu",
58 cb_data->type, &part, &cnt, &time) == 4) {
60 *cb_data->count = cnt;
61 cb_data->timespec->tv_sec = time;
62 cb_data->timespec->tv_nsec = 0;
63 } else if (sscanf(name, "dump-type%u-%u-%lu",
64 cb_data->type, &part, &time) == 3) {
66 * Check if an old format,
67 * which doesn't support holding
68 * multiple logs, remains.
72 cb_data->timespec->tv_sec = time;
73 cb_data->timespec->tv_nsec = 0;
77 entry->var.DataSize = 1024;
78 __efivar_entry_get(entry, &entry->var.Attributes,
79 &entry->var.DataSize, entry->var.Data);
80 size = entry->var.DataSize;
82 *cb_data->buf = kmalloc(size, GFP_KERNEL);
83 if (*cb_data->buf == NULL)
85 memcpy(*cb_data->buf, entry->var.Data, size);
89 static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
90 int *count, struct timespec *timespec,
91 char **buf, struct pstore_info *psi)
93 struct pstore_read_data data;
98 data.timespec = timespec;
101 return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data,
102 (struct efivar_entry **)&psi->data);
105 static int efi_pstore_write(enum pstore_type_id type,
106 enum kmsg_dump_reason reason, u64 *id,
107 unsigned int part, int count, size_t size,
108 struct pstore_info *psi)
110 char name[DUMP_NAME_LEN];
111 efi_char16_t efi_name[DUMP_NAME_LEN];
112 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
115 sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
118 for (i = 0; i < DUMP_NAME_LEN; i++)
119 efi_name[i] = name[i];
121 efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES,
122 !pstore_cannot_block_path(reason),
125 if (reason == KMSG_DUMP_OOPS)
132 struct pstore_erase_data {
134 enum pstore_type_id type;
136 struct timespec time;
141 * Clean up an entry with the same name
143 static int efi_pstore_erase_func(struct efivar_entry *entry, void *data)
145 struct pstore_erase_data *ed = data;
146 efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
147 efi_char16_t efi_name_old[DUMP_NAME_LEN];
148 efi_char16_t *efi_name = ed->name;
149 unsigned long ucs2_len = ucs2_strlen(ed->name);
150 char name_old[DUMP_NAME_LEN];
153 if (efi_guidcmp(entry->var.VendorGuid, vendor))
156 if (ucs2_strncmp(entry->var.VariableName,
157 efi_name, (size_t)ucs2_len)) {
159 * Check if an old format, which doesn't support
160 * holding multiple logs, remains.
162 sprintf(name_old, "dump-type%u-%u-%lu", ed->type,
163 (unsigned int)ed->id, ed->time.tv_sec);
165 for (i = 0; i < DUMP_NAME_LEN; i++)
166 efi_name_old[i] = name_old[i];
168 if (ucs2_strncmp(entry->var.VariableName, efi_name_old,
169 ucs2_strlen(efi_name_old)))
174 __efivar_entry_delete(entry);
175 list_del(&entry->list);
180 static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
181 struct timespec time, struct pstore_info *psi)
183 struct pstore_erase_data edata;
184 struct efivar_entry *entry = NULL;
185 char name[DUMP_NAME_LEN];
186 efi_char16_t efi_name[DUMP_NAME_LEN];
189 sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
192 for (i = 0; i < DUMP_NAME_LEN; i++)
193 efi_name[i] = name[i];
199 edata.name = efi_name;
201 efivar_entry_iter_begin();
202 found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry);
203 efivar_entry_iter_end();
206 efivar_unregister(entry);
211 static struct pstore_info efi_pstore_info = {
212 .owner = THIS_MODULE,
214 .open = efi_pstore_open,
215 .close = efi_pstore_close,
216 .read = efi_pstore_read,
217 .write = efi_pstore_write,
218 .erase = efi_pstore_erase,
221 static __init int efivars_pstore_init(void)
223 if (!efi_enabled(EFI_RUNTIME_SERVICES))
226 if (!efivars_kobject())
229 if (efivars_pstore_disable)
232 efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
233 if (!efi_pstore_info.buf)
236 efi_pstore_info.bufsize = 1024;
237 spin_lock_init(&efi_pstore_info.buf_lock);
239 pstore_register(&efi_pstore_info);
244 static __exit void efivars_pstore_exit(void)
248 module_init(efivars_pstore_init);
249 module_exit(efivars_pstore_exit);
251 MODULE_DESCRIPTION("EFI variable backend for pstore");
252 MODULE_LICENSE("GPL");