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EFIRT(9)		    Kernel Developer's Manual			EFIRT(9)

NAME
     efirt,  efi_rt_ok,  efi_get_table, efi_get_time, efi_get_time_capabilities,
     efi_reset_system, efi_set_time, efi_var_get, efi_var_nextname,  efi_var_set
     -- kernel access to UEFI runtime services

SYNOPSIS
     options EFIRT

     #include <sys/efi.h>

     int
     efi_rt_ok(void);

     int
     efi_get_table(struct uuid *uuid, void **ptr);

     int
     efi_get_time(struct efi_tm *tm);

     int
     efi_get_time_capabilities(struct efi_tmcap *tmcap);

     int
     efi_reset_system(enum efi_reset type);

     int
     efi_set_time(struct efi_tm *tm);

     int
     efi_var_get(uint16_t *name, struct uuid *vendor, uint32_t *attrib,
	   size_t *datasize, void *data);

     int
     efi_var_nextname(size_t *namesize, uint16_t *name, struct uuid *vendor);

     int
     efi_var_set(uint16_t *name, struct uuid *vendor, uint32_t attrib,
	   size_t datasize, void *data);

DESCRIPTION
     All  of  the following calls will return ENXIO if UEFI runtime services are
     not available.  efirt is currently only available on amd64 and arm64.

     The efi_rt_ok() Returns 0 if UEFI runtime services are  present  and  func-
     tional, or ENXIO if not.

     The  efi_get_table() function gets a table by uuid from the UEFI system ta-
     ble.  Returns 0 if the table was found and populates *ptr with the address.
     Returns ENXIO if the configuration table or system table  are  unset.   Re-
     turns ENOENT if the requested table cannot be found.

     The  efi_get_time()  function gets the current time from the RTC, if avail-
     able.  Returns 0 and populates  the  struct  efi_tm  on  success.	 Returns
     EINVAL  if  the  struct efi_tm is NULL, or EIO if the time could not be re-
     trieved due to a hardware error.

     The efi_get_time_capabilities() function gets  the  capabilities  from  the
     RTC.   Returns  0	and  populates the struct efi_tmcap on success.  Returns
     EINVAL if the struct efi_tm is NULL, or EIO if the time could  not  be  re-
     trieved due to a hardware error.

     The  efi_reset_system()  function requests a reset of the system.	The type
     argument may be one of the enum efi_reset values:

     EFI_RESET_COLD	 Perform a cold reset of the system, and reboot.

     EFI_RESET_WARM	 Perform a warm reset of the system, and reboot.

     EFI_RESET_SHUTDOWN  Power off the system.

     The efi_set_time() function sets the time on the RTC to the time  described
     by  the  struct  efi_tm  passed in.  Returns 0 on success, EINVAL if a time
     field is out of range, or EIO if the time could not be set due to	a  hard-
     ware error.

     The  efi_var_get()  function  fetches the variable identified by vendor and
     name.  Returns 0 and populates attrib, datasize, and data on success.  Oth-
     erwise, one of the following errors are returned:

     ENOENT	The variable was not found.

     EOVERFLOW	datasize is not sufficient to hold the variable data.	namesize
		is updated to reflect the size needed to complete the request.

     EINVAL	One  of  name,	vendor,  or  datasize  are NULL.  Alternatively,
		datasize is large enough to hold the response but data is NULL.

     EIO	The variable could not be retrieved due to a hardware error.

     EDOOFUS	The variable could not be retrieved  due  to  an  authentication
		failure.

     The  efi_var_nextname()  function is used for enumeration of variables.  On
     the initial call to efi_var_nextname(), name should  be  an  empty  string.
     Subsequent  calls	should	pass  in the last name and vendor returned until
     ENOENT is returned.  Returns 0 and populates  namesize,  name,  and  vendor
     with the next variable's data.  Otherwise, returns one of the following er-
     rors:

     ENOENT	The next variable was not found.

     EOVERFLOW	datasize  is not sufficient to hold the variable data.	namesize
		is updated to reflect the size needed to complete the request.

     EINVAL	One of name, vendor, or datasize are NULL.

     EIO	The variable could not be retrieved due to a hardware error.

     The efi_var_set() function sets the variable described by name and  vendor.
     Returns 0 if the variable has been successfully.  Otherwise, returns one of
     the following errors:

     EINVAL	Either attrib was an invalid combination of attributes, datasize
		exceeds  the  maximum  allowed size, or name is an empty Unicode
		stirng.

     EAGAIN	Not enough storage is available to hold  the  variable	and  its
		data.

     EIO	The variable could not be saved due to a hardware error.

     EROFS	The variable in question is read-only or may not be deleted.

     EDOOFUS	The variable could not be set due to an authentication failure.

     ENOENT	The variable trying to be updated or deleted was not found.

SEE ALSO
     efidev(4)

AUTHORS
     This manual page was written by Kyle Evans <kevans@FreeBSD.org>.

FreeBSD 15.1			November 2, 2021			EFIRT(9)
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