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#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");
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