1.\" 2.\" Copyright (C) 2006 M. Warner Losh <imp@FreeBSD.org>. 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.\" $FreeBSD$ 28.\" 29.Dd August 10, 2017 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.Vt typedef void (*ich_func_t)(void *arg); 39.Ft int 40.Fn config_intrhook_establish "struct intr_config_hook *hook" 41.Ft void 42.Fn config_intrhook_disestablish "struct intr_config_hook *hook" 43.Ft void 44.Fn config_intrhook_oneshot "ich_func_t func" "void *arg" 45.Sh DESCRIPTION 46The 47.Fn config_intrhook_establish 48function schedules a function to be run after interrupts have been 49enabled, but before root is mounted. 50If the system has already passed this point in its initialization, 51the function is called immediately. 52.Pp 53The 54.Fn config_intrhook_disestablish 55function removes the entry from the hook queue. 56.Pp 57The 58.Fn config_intrhook_oneshot 59function schedules a function to be run as described for 60.Fn config_intrhook_establish ; 61the entry is automatically removed from the hook queue 62after that function runs. 63This is appropriate when additional device configuration must be done 64after interrupts are enabled, but there is no need to stall the 65boot process after that. 66This function allocates memory using M_WAITOK; do not call this while 67holding any non-sleepable locks. 68.Pp 69Before root is mounted, all the previously established hooks are 70run. 71The boot process is then stalled until all handlers remove their hook 72from the hook queue with 73.Fn config_intrhook_disestablish . 74The boot process then proceeds to attempt to mount the root file 75system. 76Any driver that can potentially provide devices they wish to be 77mounted as root must use either this hook, or probe all these devices 78in the initial probe. 79Since interrupts are disabled during the probe process, many drivers 80need a method to probe for devices with interrupts enabled. 81.Pp 82The requests are made with the 83.Vt intr_config_hook 84structure. 85This structure is defined as follows: 86.Bd -literal 87struct intr_config_hook { 88 TAILQ_ENTRY(intr_config_hook) ich_links;/* Private */ 89 ich_func_t ich_func; /* function to call */ 90 void *ich_arg; /* Argument to call */ 91}; 92.Ed 93.Pp 94Storage for the 95.Vt intr_config_hook 96structure must be provided by the driver. 97It must be stable from just before the hook is established until 98after the hook is disestablished. 99.Pp 100Specifically, hooks are run at 101.Fn SI_SUB_INT_CONFIG_HOOKS , 102which is immediately after the scheduler is started, 103and just before the root file system device is discovered. 104.Sh RETURN VALUES 105A zero return value means the hook was successfully added to the queue 106(with either deferred or immediate execution). 107A non-zero return value means the hook could not be added to the queue 108because it was already on the queue. 109.Sh SEE ALSO 110.Xr DEVICE_ATTACH 9 111.Sh HISTORY 112These functions were introduced in 113.Fx 3.0 114with the CAM subsystem, but are available for any driver to use. 115.Sh AUTHORS 116.An -nosplit 117The functions were written by 118.An Justin Gibbs Aq Mt gibbs@FreeBSD.org . 119This manual page was written by 120.An M. Warner Losh Aq Mt imp@FreeBSD.org . 121