- 根目录:
- drivers
- firmware
- efi
- efi-pstore.c
#include <linux/efi.h>
#include <linux/module.h>
#include <linux/pstore.h>
#include <linux/slab.h>
#include <linux/ucs2_string.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)
{
psi->data = NULL;
return 0;
}
static int efi_pstore_close(struct pstore_info *psi)
{
psi->data = NULL;
return 0;
}
struct pstore_read_data {
u64 *id;
enum pstore_type_id *type;
int *count;
struct timespec *timespec;
bool *compressed;
char **buf;
};
static inline u64 generic_id(unsigned long timestamp,
unsigned int part, int count)
{
return (timestamp * 100 + part) * 1000 + count;
}
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], data_type;
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-%c",
cb_data->type, &part, &cnt, &time, &data_type) == 5) {
*cb_data->id = generic_id(time, part, cnt);
*cb_data->count = cnt;
cb_data->timespec->tv_sec = time;
cb_data->timespec->tv_nsec = 0;
if (data_type == 'C')
*cb_data->compressed = true;
else
*cb_data->compressed = false;
} else if (sscanf(name, "dump-type%u-%u-%d-%lu",
cb_data->type, &part, &cnt, &time) == 4) {
*cb_data->id = generic_id(time, part, cnt);
*cb_data->count = cnt;
cb_data->timespec->tv_sec = time;
cb_data->timespec->tv_nsec = 0;
*cb_data->compressed = false;
} 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 = generic_id(time, part, 0);
*cb_data->count = 0;
cb_data->timespec->tv_sec = time;
cb_data->timespec->tv_nsec = 0;
*cb_data->compressed = false;
} else
return 0;
entry->var.DataSize = 1024;
__efivar_entry_get(entry, &entry->var.Attributes,
&entry->var.DataSize, entry->var.Data);
size = entry->var.DataSize;
memcpy(*cb_data->buf, entry->var.Data,
(size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX, size));
return size;
}
/**
* efi_pstore_scan_sysfs_enter
* @entry: scanning entry
* @next: next entry
* @head: list head
*/
static void efi_pstore_scan_sysfs_enter(struct efivar_entry *pos,
struct efivar_entry *next,
struct list_head *head)
{
pos->scanning = true;
if (&next->list != head)
next->scanning = true;
}
/**
* __efi_pstore_scan_sysfs_exit
* @entry: deleting entry
* @turn_off_scanning: Check if a scanning flag should be turned off
*/
static inline void __efi_pstore_scan_sysfs_exit(struct efivar_entry *entry,
bool turn_off_scanning)
{
if (entry->deleting) {
list_del(&entry->list);
efivar_entry_iter_end();
efivar_unregister(entry);
efivar_entry_iter_begin();
} else if (turn_off_scanning)
entry->scanning = false;
}
/**
* efi_pstore_scan_sysfs_exit
* @pos: scanning entry
* @next: next entry
* @head: list head
* @stop: a flag checking if scanning will stop
*/
static void efi_pstore_scan_sysfs_exit(struct efivar_entry *pos,
struct efivar_entry *next,
struct list_head *head, bool stop)
{
__efi_pstore_scan_sysfs_exit(pos, true);
if (stop)
__efi_pstore_scan_sysfs_exit(next, &next->list != head);
}
/**
* efi_pstore_sysfs_entry_iter
*
* @data: function-specific data to pass to callback
* @pos: entry to begin iterating from
*
* You MUST call efivar_enter_iter_begin() before this function, and
* efivar_entry_iter_end() afterwards.
*
* It is possible to begin iteration from an arbitrary entry within
* the list by passing @pos. @pos is updated on return to point to
* the next entry of the last one passed to efi_pstore_read_func().
* To begin iterating from the beginning of the list @pos must be %NULL.
*/
static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
{
struct efivar_entry *entry, *n;
struct list_head *head = &efivar_sysfs_list;
int size = 0;
if (!*pos) {
list_for_each_entry_safe(entry, n, head, list) {
efi_pstore_scan_sysfs_enter(entry, n, head);
size = efi_pstore_read_func(entry, data);
efi_pstore_scan_sysfs_exit(entry, n, head, size < 0);
if (size)
break;
}
*pos = n;
return size;
}
list_for_each_entry_safe_from((*pos), n, head, list) {
efi_pstore_scan_sysfs_enter((*pos), n, head);
size = efi_pstore_read_func((*pos), data);
efi_pstore_scan_sysfs_exit((*pos), n, head, size < 0);
if (size)
break;
}
*pos = n;
return size;
}
/**
* efi_pstore_read
*
* This function returns a size of NVRAM entry logged via efi_pstore_write().
* The meaning and behavior of efi_pstore/pstore are as below.
*
* size > 0: Got data of an entry logged via efi_pstore_write() successfully,
* and pstore filesystem will continue reading subsequent entries.
* size == 0: Entry was not logged via efi_pstore_write(),
* and efi_pstore driver will continue reading subsequent entries.
* size < 0: Failed to get data of entry logging via efi_pstore_write(),
* and pstore will stop reading entry.
*/
static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
int *count, struct timespec *timespec,
char **buf, bool *compressed,
struct pstore_info *psi)
{
struct pstore_read_data data;
ssize_t size;
data.id = id;
data.type = type;
data.count = count;
data.timespec = timespec;
data.compressed = compressed;
data.buf = buf;
*data.buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL);
if (!*data.buf)
return -ENOMEM;
efivar_entry_iter_begin();
size = efi_pstore_sysfs_entry_iter(&data,
(struct efivar_entry **)&psi->data);
efivar_entry_iter_end();
if (size <= 0)
kfree(*data.buf);
return size;
}
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
unsigned int part, int count, bool compressed, 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-%c", type, part, count,
get_seconds(), compressed ? 'C' : 'D');
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 ucs2_len = ucs2_strlen(ed->name);
char name_old[DUMP_NAME_LEN];
int i;
if (efi_guidcmp(entry->var.VendorGuid, vendor))
return 0;
if (ucs2_strncmp(entry->var.VariableName,
efi_name, (size_t)ucs2_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 (ucs2_strncmp(entry->var.VariableName, efi_name_old,
ucs2_strlen(efi_name_old)))
return 0;
}
if (entry->scanning) {
/*
* Skip deletion because this entry will be deleted
* after scanning is completed.
*/
entry->deleting = true;
} else
list_del(&entry->list);
/* 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 = NULL;
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
int found, i;
unsigned int part;
do_div(id, 1000);
part = do_div(id, 100);
sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count, time.tv_sec);
for (i = 0; i < DUMP_NAME_LEN; i++)
efi_name[i] = name[i];
edata.id = part;
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);
if (found && !entry->scanning) {
efivar_entry_iter_end();
efivar_unregister(entry);
} else
efivar_entry_iter_end();
return 0;
}
static struct pstore_info efi_pstore_info = {
.owner = THIS_MODULE,
.name = "efi",
.flags = PSTORE_FLAGS_FRAGILE,
.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);
if (pstore_register(&efi_pstore_info)) {
kfree(efi_pstore_info.buf);
efi_pstore_info.buf = NULL;
efi_pstore_info.bufsize = 0;
}
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");