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diff --git a/share/man/man9/swi.9 b/share/man/man9/swi.9 new file mode 100644 index 000000000000..ea0b32b033a2 --- /dev/null +++ b/share/man/man9/swi.9 @@ -0,0 +1,228 @@ +.\" Copyright (c) 2000-2001 John H. Baldwin <jhb@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 October 30, 2000 +.Dt SWI 9 +.Os +.Sh NAME +.Nm swi_add , +.Nm swi_sched +.Nd register and schedule software interrupt handlers +.Sh SYNOPSIS +.In sys/param.h +.In sys/bus.h +.In sys/interrupt.h +.Vt "extern struct ithd *tty_ithd" ; +.Vt "extern struct ithd *clk_ithd" ; +.Vt "extern void *net_ih" ; +.Vt "extern void *softclock_ih" ; +.Vt "extern void *vm_ih" ; +.Ft int +.Fo swi_add +.Fa "struct ithd **ithdp" +.Fa "const char *name" +.Fa "driver_intr_t handler" +.Fa "void *arg" +.Fa "int pri" +.Fa "enum intr_type flags" +.Fa "void **cookiep" +.Fc +.Ft void +.Fn swi_sched "void *cookie" "int flags" +.Sh DESCRIPTION +These functions are used to register and schedule software interrupt handlers. +Software interrupt handlers are attached to a software interrupt thread, just +as hardware interrupt handlers are attached to a hardware interrupt thread. +Multiple handlers can be attached to the same thread. +Software interrupt handlers can be used to queue up less critical processing +inside of hardware interrupt handlers so that the work can be done at a later +time. +Software interrupt threads are different from other kernel threads in that they +are treated as an interrupt thread. +This means that time spent executing these threads is counted as interrupt +time, and that they can be run via a lightweight context switch. +.Pp +The +.Fn swi_add +function is used to register a new software interrupt handler. +The +.Fa ithdp +argument is an optional pointer to a +.Vt struct ithd +pointer. +If this argument points to an existing software interrupt thread, then this +handler will be attached to that thread. +Otherwise a new thread will be created, and if +.Fa ithdp +is not +.Dv NULL , +then the pointer at that address to will be modified to point to the +newly created thread. +The +.Fa name +argument is used to associate a name with a specific handler. +This name is appended to the name of the software interrupt thread that this +handler is attached to. +The +.Fa handler +argument is the function that will be executed when the handler is scheduled +to run. +The +.Fa arg +parameter will be passed in as the only parameter to +.Fa handler +when the function is executed. +The +.Fa pri +value specifies the priority of this interrupt handler relative to other +software interrupt handlers. +If an interrupt thread is created, then this value is used as the vector, +and the +.Fa flags +argument is used to specify the attributes of a handler such as +.Dv INTR_MPSAFE . +The +.Fa cookiep +argument points to a +.Vt void * +cookie. +This cookie will be set to a value that uniquely identifies this handler, +and is used to schedule the handler for execution later on. +.Pp +The +.Fn swi_sched +function is used to schedule an interrupt handler and its associated thread to +run. +The +.Fa cookie +argument specifies which software interrupt handler should be scheduled to run. +The +.Fa flags +argument specifies how and when the handler should be run and is a mask of one +or more of the following flags: +.Bl -tag -width SWI_DELAY +.It Dv SWI_DELAY +Specifies that the kernel should mark the specified handler as needing to run, +but the kernel should not schedule the software interrupt thread to run. +Instead, +.Fa handler +will be executed the next time that the software interrupt thread runs after +being scheduled by another event. +Attaching a handler to the clock software interrupt thread and using this flag +when scheduling a software interrupt handler can be used to implement the +functionality performed by +.Fn setdelayed +in earlier versions of +.Fx . +.El +.Pp +The +.Va tty_ithd +and +.Va clk_ithd +variables contain pointers to the software interrupt threads for the tty and +clock software interrupts, respectively. +.Va tty_ithd +is used to hang tty software interrupt handlers off of the same thread. +.Va clk_ithd +is used to hang delayed handlers off of the clock software interrupt thread so +that the functionality of +.Fn setdelayed +can be obtained in conjunction with +.Dv SWI_DELAY . +The +.Va net_ih , +.Va softclock_ih , +and +.Va vm_ih +handler cookies are used to schedule software interrupt threads to run for the +networking stack, clock interrupt, and VM subsystem respectively. +.Sh RETURN VALUES +The +.Fn swi_add +function returns zero on success and non-zero on failure. +.Sh ERRORS +The +.Fn swi_add +function will fail if: +.Bl -tag -width Er +.It Bq Er EAGAIN +The system-imposed limit on the total +number of processes under execution would be exceeded. +The limit is given by the +.Xr sysctl 3 +MIB variable +.Dv KERN_MAXPROC . +.It Bq Er EINVAL +The +.Fa flags +argument specifies either +.Dv INTR_ENTROPY +or +.Dv INTR_FAST . +.It Bq Er EINVAL +The +.Fa ithdp +argument points to a hardware interrupt thread. +.It Bq Er EINVAL +Either of the +.Fa name +or +.Fa handler +arguments are +.Dv NULL . +.It Bq Er EINVAL +The +.Dv INTR_EXCL +flag is specified and the interrupt thread pointed to by +.Fa ithdp +already has at least one handler, or the interrupt thread already has an +exclusive handler. +.El +.Sh SEE ALSO +.Xr ithread 9 , +.Xr taskqueue 9 +.Sh HISTORY +The +.Fn swi_add +and +.Fn swi_sched +functions first appeared in +.Fx 5.0 . +They replaced the +.Fn register_swi +function which appeared in +.Fx 3.0 +and the +.Fn setsoft* , +and +.Fn schedsoft* +functions which date back to at least +.Bx 4.4 . +.Sh BUGS +Most of the global variables described in this manual page should not be +global, or at the very least should not be declared in +.In sys/interrupt.h . |