config_intrhook.9: Use .Dv for SI_* identifier.
[dragonfly.git] / share / man / man9 / config_intrhook.9
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30.Dt CONFIG_INTRHOOK 9
31.Os
32.Sh NAME
33.Nm config_intrhook
34.Nd schedule a function to be run after interrupts have been enabled,
35but before root is mounted
36.Sh SYNOPSIS
37.In sys/kernel.h
38.Ft int
39.Fn config_intrhook_establish "struct intr_config_hook *hook"
40.Ft void
41.Fn config_intrhook_disestablish "struct intr_config_hook *hook"
42.Sh DESCRIPTION
43The
44.Fn config_intrhook_establish
45function schedules a function to be run after interrupts have been
46enabled, but before root is mounted.
47If the system has already passed this point in its initialization,
48the function is called immediately.
49.Pp
50The
51.Fn config_intrhook_disestablish
52function removes the entry from the hook queue.
53.Pp
54Before root is mounted, all the previously established hooks are
55run.
56The boot process is then stalled until all handlers remove their hook
57from the hook queue with
58.Fn config_intrhook_disestablish .
59The boot process then proceeds to attempt to mount the root file
60system.
61Any driver that can potentially provide devices they wish to be
62mounted as root must use either this hook, or probe all these devices
63in the initial probe.
64Since interrupts are disabled during the probe process, many drivers
65need a method to probe for devices with interrupts enabled.
66.Pp
67The requests are made with the
68.Vt intr_config_hook
69structure.
70This structure is defined as follows:
71.Bd -literal
72struct intr_config_hook {
73 TAILQ_ENTRY(intr_config_hook) ich_links;/* Private */
74 void (*ich_func)(void *arg); /* function to call */
75 void *ich_arg; /* Argument to call */
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76 const char *ich_desc; /* Hook description */
77 int ich_order; /* Ordering field */
78 int ich_ran; /* Private */
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79};
80.Ed
81.Pp
82Storage for the
83.Vt intr_config_hook
84structure must be provided by the driver.
85It must be stable from just before the hook is established until
86after the hook is disestablished.
87.Pp
88Specifically, hooks are run at
28e9bc39 89.Dv SI_SUB_INT_CONFIG_HOOKS ,
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90which is immediately after the scheduler is started,
91and just before the root file system device is discovered.
92.Sh RETURN VALUES
93A zero return value means the hook was successfully added to the queue
94(with either deferred or immediate execution).
95A non-zero return value means the hook could not be added to the queue
96because it was already on the queue.
97.Sh SEE ALSO
98.Xr DEVICE_ATTACH 9
99.Sh HISTORY
100These functions were introduced in
101.Fx 3.0
102with the CAM subsystem, but are available for any driver to use.
103.Sh AUTHORS
104.An -nosplit
105The functions were written by
106.An Justin Gibbs Aq gibbs@FreeBSD.org .
107This manual page was written by
108.An M. Warner Losh Aq imp@FreeBSD.org .