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EFIDEV(4)		     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  regis-
     tered  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  supple-
     mental 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;
			   int16_t	   tm_tz;
			   uint8_t	   tm_dst;
			   uint8_t	   __pad2;
		   };

     EFIIOC_SET_TIME (struct efi_tm)
	     Sets the time stored by the RTC, if the RTC is available.

     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  re-
	     turned.

     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 ports 15.1		  June 18, 2021 		       EFIDEV(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=efidev&sektion=4&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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