xref: /freebsd/share/man/man4/efidev.4 (revision 123af6ec70016f5556da5972d4d63c7d175c06d3)
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27.\" $FreeBSD$
28.\"
29.Dd August 12, 2018
30.Dt EFIDEV 4
31.Os
32.Sh NAME
33.Nm efidev ,
34.Nm efirtc
35.Nd user-mode access to UEFI runtime services
36.Sh SYNOPSIS
37To compile this driver into the kernel, place the following lines in your
38kernel configuration file:
39.Bd -ragged -offset -indent
40.Cd "options EFIRT"
41.Ed
42.Pp
43Alternatively, to load the driver as a module at boot time, place the following
44line in
45.Xr loader.conf 5 :
46.Bd -literal -offset indent
47efirt_load="YES"
48.Ed
49.Pp
50The driver may be disabled by setting the
51.Xr loader 8
52tunable
53.Va efi.rt.disabled
54to
55.Dq Li 1 .
56.Sh DESCRIPTION
57The
58.Nm
59device provides user-mode access to UEFI runtime services.
60.Nm
61also includes a driver to provide a time-of-day clock using the UEFI
62real time clock (RTC).
63However, the RTC may not always be available, based on the UEFI firmware.
64If the RTC is not available, it will not be registered as a time-of-day clock
65and the time related ioctls below will not be functional.
66.Pp
67.Nm
68provides the following ioctls defined in
69.In sys/efiio.h
70with supplemental structures and constants defined in
71.In sys/efi.h :
72.Bl -tag -width indent
73.It Dv EFIIOC_GET_TABLE Pq Vt "struct efi_get_table_ioc"
74Get a table by uuid from the UEFI system table.
75.Bd -literal -offset indent
76struct efi_get_table_ioc {
77	struct uuid uuid;
78	void *ptr;
79};
80.Ed
81.It Dv EFIIOC_GET_TIME Pq Vt "struct efi_tm"
82Get the time from the RTC, if the RTC is available.
83The
84.Vt struct efi_tm
85passed is populated with the current time, unless an error occurs.
86.Bd -literal -offset indent
87struct efi_tm {
88	uint16_t	tm_year;
89	uint8_t		tm_mon
90	uint8_t		tm_mday
91	uint8_t		tm_hour;
92	uint8_t		tm_min;
93	uint8_t		tm_sec;
94	uint8_t		 __pad1;
95	uint32_t	tm_nsec;
96	int16_t		tm_tz;
97	uint8_t		tm_dst;
98	uint8_t		__pad2;
99};
100.Ed
101.It Dv EFIIOC_SET_TIME Pq Vt "struct efi_tm"
102Sets the time stored by the RTC, if the RTC is available.
103.It Dv EFIIOC_VAR_GET Pq Vt "struct efi_var_ioc"
104Gets data from the variable described by the vendor and name fields of the
105.Vt struct efi_var_ioc
106into the
107.Fa data
108field.
109.Dv EFIIOC_VAR_GET Pq Vt "struct efi_var_ioc"
110will also populate the
111.Fa attrib
112field.
113.Bd -literal
114struct efi_var_ioc {
115	efi_char	*name;
116	size_t		 namesize;
117	struct uuid	 vendor;
118	uint32_t	 attrib;
119	void		*data;
120	size_t		 datasize;
121};
122.Ed
123.It Dv EFIIOC_VAR_NEXT Pq Vt "struct efi_var_ioc"
124Used for enumerating all UEFI variables.
125The initial call should use an empty string for the name attribute.
126Subsequent calls should supply the vendor uuid and name of the last variable
127returned.
128.It Dv EFIIOC_VAR_SET Pq Vt "struct efi_var_ioc"
129Sets data and attributes for the variable described by the name and vendor in
130the
131.Vt struct efi_var_ioc .
132.El
133.Sh FILES
134.Bl -tag -width /dev/efi
135.It Pa /dev/efi
136.El
137.Sh SEE ALSO
138.Xr efivar 3 ,
139.Xr efirt 9
140.Sh HISTORY
141A
142.Nm
143device first appeared in
144.Fx 11.1 .
145.Sh BUGS
146.Nm
147is currently only available on amd64 and arm64.
148