FreeBSD manual
download PDF document: efidev.4.pdf
EFIDEV(4) FreeBSD Kernel Interfaces Manual EFIDEV(4)
NAME
efidev, efirtc - user-mode access to UEFI runtime services
SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
options EFIRT
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
efirt_load="YES"
The driver may be disabled by setting the loader(8) tunable
efi.rt.disabled to "1".
DESCRIPTION
The efidev device provides user-mode access to UEFI runtime services.
efidev also includes a driver to provide a time-of-day clock using the
UEFI real time clock (RTC). However, the RTC may not always be
available, based on the UEFI firmware. If the RTC is not available, it
will not be registered as a time-of-day clock and the time related ioctls
below will not be functional.
efidev provides the following ioctls defined in <sys/efiio.h> with
supplemental structures and constants defined in <sys/efi.h>:
EFIIOC_GET_TABLE (struct efi_get_table_ioc)
Copy the UEFI table specified by the uuid field of the struct
efi_get_table_ioc into the buf field. The memory size for the
buf field can be queried by passing NULL pointer as a buf value.
The required size will be stored in the table_len field. The
size of the allocated memory must be specified in the buf_len
field.
struct efi_get_table_ioc {
void *buf;
struct uuid uuid;
size_t table_len;
size_t buf_len;
};
EFIIOC_GET_TIME (struct efi_tm)
Get the time from the RTC, if the RTC is available. The struct
efi_tm passed is populated with the current time, unless an error
occurs.
struct efi_tm {
uint16_t tm_year;
uint8_t tm_mon
uint8_t tm_mday
uint8_t tm_hour;
uint8_t tm_min;
uint8_t tm_sec;
uint8_t __pad1;
uint32_t tm_nsec;
EFIIOC_VAR_GET (struct efi_var_ioc)
Gets data from the variable described by the vendor and name
fields of the struct efi_var_ioc into the data field.
EFIIOC_VAR_GET (struct efi_var_ioc) will also populate the attrib
field.
struct efi_var_ioc {
efi_char *name;
size_t namesize;
struct uuid vendor;
uint32_t attrib;
void *data;
size_t datasize;
};
EFIIOC_VAR_NEXT (struct efi_var_ioc)
Used for enumerating all UEFI variables. The initial call should
use an empty string for the name attribute. Subsequent calls
should supply the vendor uuid and name of the last variable
returned.
EFIIOC_VAR_SET (struct efi_var_ioc)
Sets data and attributes for the variable described by the name
and vendor in the struct efi_var_ioc.
FILES
/dev/efi
SEE ALSO
efivar(3), efirt(9)
HISTORY
A efidev device first appeared in FreeBSD 11.1.
BUGS
efidev is currently only available on amd64 and arm64.
FreeBSD 14.0-RELEASE-p6 June 18, 2021 FreeBSD 14.0-RELEASE-p6