diff options
Diffstat (limited to 'drivers/firmware/efi/efi-pstore.c')
| -rw-r--r-- | drivers/firmware/efi/efi-pstore.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c new file mode 100644 index 00000000000..47ae712c950 --- /dev/null +++ b/drivers/firmware/efi/efi-pstore.c @@ -0,0 +1,244 @@ +#include <linux/efi.h> +#include <linux/module.h> +#include <linux/pstore.h> + +#define DUMP_NAME_LEN 52 + +static bool efivars_pstore_disable = + IS_ENABLED(CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE); + +module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644); + +#define PSTORE_EFI_ATTRIBUTES \ + (EFI_VARIABLE_NON_VOLATILE | \ + EFI_VARIABLE_BOOTSERVICE_ACCESS | \ + EFI_VARIABLE_RUNTIME_ACCESS) + +static int efi_pstore_open(struct pstore_info *psi) +{ + efivar_entry_iter_begin(); + psi->data = NULL; + return 0; +} + +static int efi_pstore_close(struct pstore_info *psi) +{ + efivar_entry_iter_end(); + psi->data = NULL; + return 0; +} + +struct pstore_read_data { + u64 *id; + enum pstore_type_id *type; + int *count; + struct timespec *timespec; + char **buf; +}; + +static int efi_pstore_read_func(struct efivar_entry *entry, void *data) +{ + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; + struct pstore_read_data *cb_data = data; + char name[DUMP_NAME_LEN]; + int i; + int cnt; + unsigned int part; + unsigned long time, size; + + if (efi_guidcmp(entry->var.VendorGuid, vendor)) + return 0; + + for (i = 0; i < DUMP_NAME_LEN; i++) + name[i] = entry->var.VariableName[i]; + + if (sscanf(name, "dump-type%u-%u-%d-%lu", + cb_data->type, &part, &cnt, &time) == 4) { + *cb_data->id = part; + *cb_data->count = cnt; + cb_data->timespec->tv_sec = time; + cb_data->timespec->tv_nsec = 0; + } else if (sscanf(name, "dump-type%u-%u-%lu", + cb_data->type, &part, &time) == 3) { + /* + * Check if an old format, + * which doesn't support holding + * multiple logs, remains. + */ + *cb_data->id = part; + *cb_data->count = 0; + cb_data->timespec->tv_sec = time; + cb_data->timespec->tv_nsec = 0; + } else + return 0; + + __efivar_entry_size(entry, &size); + *cb_data->buf = kmalloc(size, GFP_KERNEL); + if (*cb_data->buf == NULL) + return -ENOMEM; + memcpy(*cb_data->buf, entry->var.Data, size); + return size; +} + +static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, + int *count, struct timespec *timespec, + char **buf, struct pstore_info *psi) +{ + struct pstore_read_data data; + + data.id = id; + data.type = type; + data.count = count; + data.timespec = timespec; + data.buf = buf; + + return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data, + (struct efivar_entry **)&psi->data); +} + +static int efi_pstore_write(enum pstore_type_id type, + enum kmsg_dump_reason reason, u64 *id, + unsigned int part, int count, size_t size, + struct pstore_info *psi) +{ + char name[DUMP_NAME_LEN]; + efi_char16_t efi_name[DUMP_NAME_LEN]; + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; + int i, ret = 0; + + sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, + get_seconds()); + + for (i = 0; i < DUMP_NAME_LEN; i++) + efi_name[i] = name[i]; + + efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES, + !pstore_cannot_block_path(reason), + size, psi->buf); + + if (reason == KMSG_DUMP_OOPS) + efivar_run_worker(); + + *id = part; + return ret; +}; + +struct pstore_erase_data { + u64 id; + enum pstore_type_id type; + int count; + struct timespec time; + efi_char16_t *name; +}; + +/* + * Clean up an entry with the same name + */ +static int efi_pstore_erase_func(struct efivar_entry *entry, void *data) +{ + struct pstore_erase_data *ed = data; + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; + efi_char16_t efi_name_old[DUMP_NAME_LEN]; + efi_char16_t *efi_name = ed->name; + unsigned long utf16_len = utf16_strlen(ed->name); + char name_old[DUMP_NAME_LEN]; + int i; + + if (efi_guidcmp(entry->var.VendorGuid, vendor)) + return 0; + + if (utf16_strncmp(entry->var.VariableName, + efi_name, (size_t)utf16_len)) { + /* + * Check if an old format, which doesn't support + * holding multiple logs, remains. + */ + sprintf(name_old, "dump-type%u-%u-%lu", ed->type, + (unsigned int)ed->id, ed->time.tv_sec); + + for (i = 0; i < DUMP_NAME_LEN; i++) + efi_name_old[i] = name_old[i]; + + if (utf16_strncmp(entry->var.VariableName, efi_name_old, + utf16_strlen(efi_name_old))) + return 0; + } + + /* found */ + __efivar_entry_delete(entry); + return 1; +} + +static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, + struct timespec time, struct pstore_info *psi) +{ + struct pstore_erase_data edata; + struct efivar_entry *entry; + char name[DUMP_NAME_LEN]; + efi_char16_t efi_name[DUMP_NAME_LEN]; + int found, i; + + sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count, + time.tv_sec); + + for (i = 0; i < DUMP_NAME_LEN; i++) + efi_name[i] = name[i]; + + edata.id = id; + edata.type = type; + edata.count = count; + edata.time = time; + edata.name = efi_name; + + efivar_entry_iter_begin(); + found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry); + efivar_entry_iter_end(); + + if (found) + efivar_unregister(entry); + + return 0; +} + +static struct pstore_info efi_pstore_info = { + .owner = THIS_MODULE, + .name = "efi", + .open = efi_pstore_open, + .close = efi_pstore_close, + .read = efi_pstore_read, + .write = efi_pstore_write, + .erase = efi_pstore_erase, +}; + +static __init int efivars_pstore_init(void) +{ + if (!efi_enabled(EFI_RUNTIME_SERVICES)) + return 0; + + if (!efivars_kobject()) + return 0; + + if (efivars_pstore_disable) + return 0; + + efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL); + if (!efi_pstore_info.buf) + return -ENOMEM; + + efi_pstore_info.bufsize = 1024; + spin_lock_init(&efi_pstore_info.buf_lock); + + pstore_register(&efi_pstore_info); + + return 0; +} + +static __exit void efivars_pstore_exit(void) +{ +} + +module_init(efivars_pstore_init); +module_exit(efivars_pstore_exit); + +MODULE_DESCRIPTION("EFI variable backend for pstore"); +MODULE_LICENSE("GPL"); |