xref: /freebsd/share/man/man9/efirt.9 (revision 2fe85640b2a3bf5c377dd180e40cd3d6e1a4f1f4)

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.Dd November 2, 2021
.Dt EFIRT 9
.Os
.Sh NAME
.Nm efirt ,
.Nm efi_rt_ok ,
.Nm efi_get_table ,
.Nm efi_get_time ,
.Nm efi_get_time_capabilities ,
.Nm efi_reset_system ,
.Nm efi_set_time ,
.Nm efi_var_get ,
.Nm efi_var_nextname ,
.Nm efi_var_set
.Nd kernel access to UEFI runtime services
.Sh SYNOPSIS
.Cd "options EFIRT"
.Pp
.In sys/efi.h
.Ft int
.Fn efi_rt_ok "void"
.Ft int
.Fn efi_get_table "struct uuid *uuid" "void **ptr"
.Ft int
.Fn efi_get_time "struct efi_tm *tm"
.Ft int
.Fn efi_get_time_capabilities "struct efi_tmcap *tmcap"
.Ft int
.Fn efi_reset_system "enum efi_reset type"
.Ft int
.Fn efi_set_time "struct efi_tm *tm"
.Ft int
.Fn efi_var_get "uint16_t *name" "struct uuid *vendor" "uint32_t *attrib" \
    "size_t *datasize" "void *data"
.Ft int
.Fn efi_var_nextname "size_t *namesize" "uint16_t *name" "struct uuid *vendor"
.Ft int
.Fn efi_var_set "uint16_t *name" "struct uuid *vendor" "uint32_t attrib" \
    "size_t datasize" "void *data"
.Sh DESCRIPTION
All of the following calls will return
.Dv ENXIO
if UEFI runtime services are not available.
.Nm
is currently only available on amd64 and arm64.
.Pp
The
.Fn efi_rt_ok
Returns 0 if UEFI runtime services are present and functional, or
.Dv ENXIO
if not.
.Pp
The
.Fn efi_get_table
function gets a table by uuid from the UEFI system table.
Returns 0 if the table was found and populates *ptr with the address.
Returns
.Dv ENXIO
if the configuration table or system table are unset.
Returns
.Dv ENOENT
if the requested table cannot be found.
.Pp
The
.Fn efi_get_time
function gets the current time from the RTC, if available.
Returns 0 and populates the
.Vt struct efi_tm
on success.
Returns
.Dv EINVAL
if the
.Vt struct efi_tm
is
.Dv NULL ,
or
.Dv EIO
if the time could not be retrieved due to a hardware error.
.Pp
The
.Fn efi_get_time_capabilities
function gets the capabilities from the RTC.
Returns 0 and populates the
.Vt struct efi_tmcap
on success.
Returns
.Dv EINVAL
if the
.Vt struct efi_tm
is
.Dv NULL ,
or
.Dv EIO
if the time could not be retrieved due to a hardware error.
.Pp
The
.Fn efi_reset_system
function requests a reset of the system.
The
.Fa type
argument may be one of the
.Vt enum efi_reset
values:
.Bl -tag -width ".Dv EFI_RESET_SHUTDOWN"
.It Dv EFI_RESET_COLD
Perform a cold reset of the system, and reboot.
.It Dv EFI_RESET_WARM
Perform a warm reset of the system, and reboot.
.It Dv EFI_RESET_SHUTDOWN
Power off the system.
.El
.Pp
The
.Fn efi_set_time
function sets the time on the RTC to the time described by the
.Vt struct efi_tm
passed in.
Returns 0 on success,
.Dv EINVAL
if a time field is out of range, or
.Dv EIO
if the time could not be set due to a hardware error.
.Pp
The
.Fn efi_var_get
function fetches the variable identified by
.Fa vendor
and
.Fa name .
Returns 0 and populates
.Fa attrib ,
.Fa datasize ,
and
.Fa data
on success.
Otherwise, one of the following errors are returned:
.Bl -tag -width ".Dv EOVERFLOW"
.It Dv ENOENT
The variable was not found.
.It Dv EOVERFLOW
.Fa datasize
is not sufficient to hold the variable data.
.Fa namesize
is updated to reflect the size needed to complete the request.
.It Dv EINVAL
One of
.Fa name ,
.Fa vendor ,
or
.Fa datasize
are NULL.
Alternatively,
.Fa datasize
is large enough to hold the response but
.Fa data
is NULL.
.It Dv EIO
The variable could not be retrieved due to a hardware error.
.It Dv EDOOFUS
The variable could not be retireved due to an authentication failure.
.El
.Pp
The
.Fn efi_var_nextname
function is used for enumeration of variables.
On the initial call to
.Fn efi_var_nextname ,
.Fa name
should be an empty string.
Subsequent calls should pass in the last
.Fa name
and
.Fa vendor
returned until
.Dv ENOENT
is returned.
Returns 0 and populates
.Fa namesize ,
.Fa name ,
and
.Fa vendor
with the next variable's data.
Otherwise, returns one of the following errors:
.Bl -tag -width ".Dv EOVERFLOW"
.It Dv ENOENT
The next variable was not found.
.It Dv EOVERFLOW
.Fa datasize
is not sufficient to hold the variable data.
.Fa namesize
is updated to reflect the size needed to complete the request.
.It Dv EINVAL
One of
.Fa name ,
.Fa vendor ,
or
.Fa datasize
are NULL.
.It Dv EIO
The variable could not be retrieved due to a hardware error.
.El
.Pp
The
.Fn efi_var_set
function sets the variable described by
.Fa name
and
.Fa vendor .
Returns 0 if the variable has been successfully.
Otherwise, returns one of the following errors:
.Bl -tag -width ".Dv EOVERFLOW"
.It Dv EINVAL
Either
.Fa attrib
was an invalid combination of attributes,
.Fa datasize
exceeds the maximum allowed size, or
.Fa name
is an empty Unicode stirng.
.It Dv EAGAIN
Not enough storage is available to hold the variable and its data.
.It Dv EIO
The variable could not be saved due to a hardware error.
.It Dv EROFS
The variable in question is read-only or may not be deleted.
.It Dv EDOOFUS
The variable could not be set due to an authentication failure.
.It Dv ENOENT
The variable trying to be updated or deleted was not found.
.El
.Sh SEE ALSO
.Xr efidev 4
.Sh AUTHORS
This manual page was written by
.An Kyle Evans Aq Mt kevans@FreeBSD.org .