diff options
Diffstat (limited to 'share/man/man4/apic.4')
-rw-r--r-- | share/man/man4/apic.4 | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/share/man/man4/apic.4 b/share/man/man4/apic.4 new file mode 100644 index 0000000..0856232 --- /dev/null +++ b/share/man/man4/apic.4 @@ -0,0 +1,77 @@ +.\" Copyright (c) 2011 Alexander Motin <mav@FreeBSD.org> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd December 20, 2011 +.Dt APIC 4 +.Os +.Sh NAME +.Nm apic +.Nd Advanced Programmable Interrupt Controller (APIC) driver +.Sh SYNOPSIS +This driver is a mandatory part of amd64 kernel. +To compile this driver into i386 or pc98 kernel, +place the following line in your +kernel configuration file: +.Bd -ragged -offset indent +.Cd "device apic" +.Ed +.Pp +The following tunable is settable from the +.Xr loader 8 : +.Bl -ohang +.It Va hint.apic. Ns Ar X Ns Va .clock +controls event timers functionality support. Setting to 0, disables it. +Default value is 1. +.It Va hint.apic. Ns Ar X Ns Va .disabled +Set this to 1 to disable APIC support, falling back to the legacy PIC. +.El +.Sh DESCRIPTION +There are two components in the Intel APIC system, the local APIC (LAPIC) +and the I/O APIC. +There is one local APIC in each CPU in the system. +There is typically one I/O APIC for each peripheral bus in the system. +.Pp +Local APICs manage all external interrupts for a specific processor. +In addition, they are able to accept and generate inter-processor interrupts +(IPIs). +.Pp +I/O APICs contain a redirection table, which is used to route the interrupts +they receive from peripheral buses to one or more local APICs. +.Pp +Each local APIC includes one 32-bit programmable timer. +This driver uses them to supply kernel with one event timer named "LAPIC". +Event timer provided by the driver supports both one-shot an periodic modes. +Because of local APIC nature it is per-CPU. +The timer frequency is not reported by the platform and so automatically +measured by the driver on the first use. +Depending on CPU model this timer may stop in C3 and deeper CPU sleep states. +Driver automatically adjusts event timer priority and reports it to prevent +entering dangerous sleep states when it is used. +.Sh SEE ALSO +.Xr atrtc 4 , +.Xr attimer 4 , +.Xr eventtimers 4 , +.Xr hpet 4 |