xref: /freebsd/share/man/man9/DECLARE_MODULE.9 (revision 389e4940069316fe667ffa263fa7d6390d0a960f)
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29.\" $FreeBSD$
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31.Dd February 13, 2018
32.Dt DECLARE_MODULE 9
33.Os
34.Sh NAME
35.Nm DECLARE_MODULE
36.Nd kernel module declaration macro
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/kernel.h
40.In sys/module.h
41.Fn DECLARE_MODULE "name" "moduledata_t data" "sub" "order"
42.Fn DECLARE_MODULE_TIED "name" "moduledata_t data" "sub" "order"
43.Sh DESCRIPTION
44The
45.Fn DECLARE_MODULE
46macro declares a generic kernel module.
47It is used to register the module with the system, using the
48.Fn SYSINIT
49macro.
50.Fn DECLARE_MODULE
51is usually used within other macros, such as
52.Xr DRIVER_MODULE 9 ,
53.Xr DEV_MODULE 9
54and
55.Xr SYSCALL_MODULE 9 .
56Of course, it can also be called directly, for example in
57order to implement dynamic sysctls.
58.Pp
59A module declared with
60.Fn DECLARE_MODULE_TIED
61will load only if the running kernel version
62(as specified by
63.Dv __FreeBSD_version )
64is identical to that on which it was built.
65This declaration should be used by modules which depend on interfaces beyond
66the stable kernel KBI (such as ABI emulators or hypervisors that rely on
67internal kernel structures).
68.Pp
69The arguments are:
70.Bl -tag -width indent
71.It Fa name
72The module name, which will be used in the
73.Fn SYSINIT
74call to identify the module.
75.It Fa data
76A
77.Vt moduledata_t
78structure, which contains two main items, the official name of the
79module name, which will be used in the
80.Vt module_t
81structure and a pointer to the event handler function of type
82.Vt modeventhand_t .
83.It Fa sub
84An argument directed to the
85.Fn SYSINIT
86macro.
87Valid values for this are contained in the
88.Vt sysinit_sub_id
89enumeration
90(see
91.In sys/kernel.h )
92and specify the type of system startup interfaces.
93The
94.Xr DRIVER_MODULE 9
95macro uses a value of
96.Dv SI_SUB_DRIVERS
97here for example, since these modules contain a driver for a device.
98For kernel modules that are loaded at runtime, a value of
99.Dv SI_SUB_EXEC
100is common.
101.It Fa order
102An argument for
103.Fn SYSINIT .
104It represents the KLDs order of initialization within the subsystem.
105Valid values are defined in the
106.Vt sysinit_elem_order
107enumeration
108.Pq In sys/kernel.h .
109.El
110.Sh SEE ALSO
111.Xr DEV_MODULE 9 ,
112.Xr DRIVER_MODULE 9 ,
113.Xr module 9 ,
114.Xr SYSCALL_MODULE 9
115.Pp
116.Pa /usr/include/sys/kernel.h ,
117.Pa /usr/share/examples/kld
118.Sh AUTHORS
119.An -nosplit
120This manual page was written by
121.An Alexander Langer Aq Mt alex@FreeBSD.org ,
122inspired by the KLD Facility Programming Tutorial by
123.An Andrew Reiter Aq Mt arr@watson.org .
124