1.\" 2.\" Copyright (C) 2006 M. Warner Losh <imp@FreeBSD.org>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25.\" DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man9/config_intrhook.9,v 1.4 2006/12/14 14:33:13 mpp Exp $ 28.\" 29.Dd July 10, 2012 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 */ 76 const char *ich_desc; /* Hook description */ 77 int ich_order; /* Ordering field */ 78 int ich_ran; /* Private */ 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 89.Dv SI_SUB_INT_CONFIG_HOOKS , 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 Mt gibbs@FreeBSD.org . 107This manual page was written by 108.An M. Warner Losh Aq Mt imp@FreeBSD.org . 109