Add efidev(4)/efirt(9)

Document efidev(4), provider of userland access to EFI Runtime Services. A link is created to efirtc(4), which handles the time-of-day clock side.

efirt(9) is the kernel side of this.

Reviewed by:	imp, kib (earlier version)
Differential Revision:	https://reviews.freebsd.org/D16696
This commit is contained in:
kevans 2018-08-17 04:17:51 +00:00
parent e9d18a0795
commit 1117e03b1e
5 changed files with 402 additions and 0 deletions

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@ -92,6 +92,8 @@ This function is not actually implemented.
.Sh BUGS
No facilities exist to process the strings as native UTF.
This is a limitation in the Linux libefivar library interface.
.Sh SEE ALSO
.Xr efidev 4
.Sh AUTHORS
.An -nosplit
This software was originally written by

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@ -900,6 +900,12 @@ _dtrace_provs= dtrace_io.4 \
dtrace_udplite.4
.endif
.if ${MK_EFI} != "no"
MAN+= efidev.4
MLINKS+= efidev.4 efirtc.4
.endif
.if ${MK_ISCSI} != "no"
MAN+= cfiscsi.4
MAN+= iscsi.4

143
share/man/man4/efidev.4 Normal file
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@ -0,0 +1,143 @@
.\"-
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
.\"
.\" Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd August 12, 2018
.Dt EFIDEV 4
.Os
.Sh NAME
.Nm efidev ,
.Nm efirtc
.Nd user-mode access to UEFI runtime services
.Sh SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
.Bd -ragged -offset -indent
.Cd "options EFIRT"
.Ed
.Pp
Alternatively, to load the driver as a module at boot time, place the following
line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
efirt_load="YES"
.Ed
.Pp
.Nm
may be disabled by setting the
.Xr loader 8
tunable
.Va efi.rt.disabled
to 1.
.Pp
.Nm
is currently only available on amd64 and arm64.
.Sh DESCRIPTION
The
.Nm
device provides user-mode access to UEFI runtime services.
.Nm
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.
.Pp
.Nm
provides the following ioctls defined in
.In sys/efiio.h
with supplemental structures and constants defined in
.In sys/efi.h :
.Bl -tag -width ".Dv EFIIOC_GET_TABLE"
.It Dv EFIIOC_GET_TABLE Pq Vt "struct efi_get_table_ioc"
Get a table by uuid from the UEFI system table.
.Bd -literal
struct efi_get_table_ioc {
struct uuid uuid;
void *ptr;
};
.Ed
.It Dv EFIIOC_GET_TIME Pq Vt "struct efi_tm"
Get the time from the RTC, if the RTC is available.
The
.Vt struct efi_tm
passed is populated with the current time, unless an error occurs.
.Bd -literal
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;
};
.Ed
.It Dv EFIIOC_SET_TIME Pq Vt "struct efi_tm"
Sets the time stored by the RTC, if the RTC is available.
.It Dv EFIIOC_VAR_GET Pq Vt "struct efi_var_ioc"
Gets data from the variable described by the vendor and name fields of the
.Vt struct efi_var_ioc
into the aata field.
.Dv EFIIOC_VAR_GET Pq Vt "struct efi_var_ioc"
will also populate the attrib field.
.Bd -literal
struct efi_var_ioc {
efi_char *name;
size_t namesize;
struct uuid vendor;
uint32_t attrib;
void *data;
size_t datasize;
};
.Ed
.It Dv EFIIOC_VAR_NEXT Pq Vt "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.
.It Dv EFIIOC_VAR_SET Pq Vt "struct efi_var_ioc"
Sets data and attributes for the variable described by the name and vendor in
the
.Vt struct efi_var_ioc .
.El
.Sh FILES
.Bl -tag -width /dev/efi
.It Pa /dev/efi
.El
.Sh SEE ALSO
.Xr efivar 3
.Xr efirt 9
.Sh HISTORY
A
.Nm
device first appeared in
.Fx 11.1 .

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@ -123,6 +123,7 @@ MAN= accept_filter.9 \
drbr.9 \
driver.9 \
DRIVER_MODULE.9 \
efirt.9 \
epoch.9 \
EVENTHANDLER.9 \
eventtimers.9 \

250
share/man/man9/efirt.9 Normal file
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@ -0,0 +1,250 @@
.\"-
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
.\"
.\" Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd August 12, 2018
.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 "void"
.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 warm reset and reboot of the system.
.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 varialbe 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 .