363 lines
9.3 KiB
Groff
363 lines
9.3 KiB
Groff
.\" Copyright (c) 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 August 25, 2006
|
|
.Dt ITHREAD 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ithread_add_handler ,
|
|
.Nm ithread_create ,
|
|
.Nm ithread_destroy ,
|
|
.Nm ithread_priority ,
|
|
.Nm ithread_remove_handler ,
|
|
.Nm ithread_schedule
|
|
.Nd kernel interrupt threads
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In sys/bus.h
|
|
.In sys/interrupt.h
|
|
.Ft int
|
|
.Fo ithread_add_handler
|
|
.Fa "struct ithd *ithread"
|
|
.Fa "const char *name"
|
|
.Fa "driver_intr_t handler"
|
|
.Fa "void *arg"
|
|
.Fa "u_char pri"
|
|
.Fa "enum intr_type flags"
|
|
.Fa "void **cookiep"
|
|
.Fc
|
|
.Ft int
|
|
.Fo ithread_create
|
|
.Fa "struct ithd **ithread"
|
|
.Fa "int vector"
|
|
.Fa "int flags"
|
|
.Fa "void (*disable)(int)"
|
|
.Fa "void (*enable)(int)"
|
|
.Fa "const char *fmt"
|
|
.Fa "..."
|
|
.Fc
|
|
.Ft int
|
|
.Fn ithread_destroy "struct ithd *ithread"
|
|
.Ft u_char
|
|
.Fn ithread_priority "enum intr_type flags"
|
|
.Ft int
|
|
.Fn ithread_remove_handler "void *cookie"
|
|
.Ft int
|
|
.Fn ithread_schedule "struct ithd *ithread" "int do_switch"
|
|
.Sh DESCRIPTION
|
|
Interrupt threads are kernel threads that run a list of handlers when
|
|
triggered by either a hardware or software interrupt.
|
|
Each interrupt handler has a name, handler function, handler argument,
|
|
priority, and various flags.
|
|
Each interrupt thread maintains a list of handlers sorted by priority.
|
|
This results in higher priority handlers being executed prior to lower
|
|
priority handlers.
|
|
Each thread assumes the priority of its highest priority handler for its
|
|
process priority, or
|
|
.Dv PRIO_MAX
|
|
if it has no handlers.
|
|
Interrupt threads are also associated with a single interrupt source,
|
|
represented as a vector number.
|
|
.Pp
|
|
The
|
|
.Fn ithread_create
|
|
function creates a new interrupt thread.
|
|
The
|
|
.Fa ithread
|
|
argument points to an
|
|
.Vt struct ithd
|
|
pointer that will point to the newly created thread upon success.
|
|
The
|
|
.Fa vector
|
|
argument specifies the interrupt source to associate this thread with.
|
|
The
|
|
.Fa flags
|
|
argument is a mask of properties of this thread.
|
|
The only valid flag currently for
|
|
.Fn ithread_create
|
|
is
|
|
.Dv IT_SOFT
|
|
to specify that this interrupt thread is a software interrupt.
|
|
The
|
|
.Fa enable
|
|
and
|
|
.Fa disable
|
|
arguments specify optional functions used to enable and disable this
|
|
interrupt thread's interrupt source.
|
|
The functions receive the vector corresponding to the thread's interrupt
|
|
source as their only argument.
|
|
The remaining arguments form a
|
|
.Xr printf 9
|
|
argument list that is used to build the base name of the new ithread.
|
|
The full name of an interrupt thread is formed by concatenating the base
|
|
name of an interrupt thread with the names of all of its interrupt handlers.
|
|
.Pp
|
|
The
|
|
.Fn ithread_destroy
|
|
function destroys a previously created interrupt thread by releasing its
|
|
resources and arranging for the backing kernel thread to terminate.
|
|
An interrupt thread can only be destroyed if it has no handlers remaining.
|
|
.Pp
|
|
The
|
|
.Fn ithread_add_handler
|
|
function adds a new handler to an existing interrupt thread specified by
|
|
.Fa ithread .
|
|
The
|
|
.Fa name
|
|
argument specifies a name for this handler.
|
|
The
|
|
.Fa handler
|
|
and
|
|
.Fa arg
|
|
arguments provide the function to execute for this handler and an argument
|
|
to pass to it.
|
|
The
|
|
.Fa pri
|
|
argument specifies the priority of this handler and is used both in sorting
|
|
it in relation to the other handlers for this thread and to specify the
|
|
priority of the backing kernel thread.
|
|
The
|
|
.Fa flags
|
|
argument can be used to specify properties of this handler as defined in
|
|
.In sys/bus.h .
|
|
If
|
|
.Fa cookiep
|
|
is not
|
|
.Dv NULL ,
|
|
then it will be assigned a cookie that can be used later to remove this
|
|
handler.
|
|
.Pp
|
|
The
|
|
.Fn ithread_remove_handler
|
|
removes a handler from an interrupt thread.
|
|
The
|
|
.Fa cookie
|
|
argument specifies the handler to remove from its thread.
|
|
.Pp
|
|
The
|
|
.Fn ithread_schedule
|
|
function schedules an interrupt thread to run.
|
|
If the
|
|
.Fa do_switch
|
|
argument is non-zero and the interrupt thread is idle, then a context switch
|
|
will be forced after putting the interrupt thread on the run queue.
|
|
.Pp
|
|
The
|
|
.Fn ithread_priority
|
|
function translates the
|
|
.Dv INTR_TYPE_*
|
|
interrupt flags into interrupt handler priorities.
|
|
.Pp
|
|
The interrupt flags not related to the type of a particular interrupt
|
|
.Pq Dv INTR_TYPE_*
|
|
can be used to specify additional properties of both hardware and software
|
|
interrupt handlers.
|
|
The
|
|
.Dv INTR_EXCL
|
|
flag specifies that this handler cannot share an interrupt thread with
|
|
another handler.
|
|
The
|
|
.Dv INTR_FAST
|
|
flag specifies that when this handler is executed, it should be run immediately
|
|
rather than being run asynchronously when its interrupt thread is scheduled to
|
|
run.
|
|
The
|
|
.Dv INTR_FAST
|
|
flag implies
|
|
.Dv INTR_EXCL .
|
|
The
|
|
.Dv INTR_MPSAFE
|
|
flag specifies that this handler is MP safe in that it does not need the
|
|
Giant mutex to be held while it is executed.
|
|
The
|
|
.Dv INTR_ENTROPY
|
|
flag specifies that the interrupt source this handler is tied to is a good
|
|
source of entropy, and thus that entropy should be gathered when an interrupt
|
|
from the handler's source triggers.
|
|
Presently, the
|
|
.Dv INTR_FAST
|
|
and
|
|
.Dv INTR_ENTROPY
|
|
flags are not valid for software interrupt handlers.
|
|
.Pp
|
|
It is not permitted to sleep in an interrupt thread; hence, any memory
|
|
or zone allocations in an interrupt thread should be specified with the
|
|
.Dv M_NOWAIT
|
|
flag set.
|
|
Any allocation errors must be handled thereafter.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn ithread_add_handler ,
|
|
.Fn ithread_create ,
|
|
.Fn ithread_destroy ,
|
|
.Fn ithread_remove_handler ,
|
|
and
|
|
.Fn ithread_schedule
|
|
functions return zero on success and non-zero on failure.
|
|
The
|
|
.Fn ithread_priority
|
|
function returns a process priority corresponding to the passed in interrupt
|
|
flags.
|
|
.Sh EXAMPLES
|
|
The
|
|
.Fn swi_add
|
|
function demonstrates the use of
|
|
.Fn ithread_create
|
|
and
|
|
.Fn ithread_add_handler .
|
|
.Bd -literal -offset indent
|
|
int
|
|
swi_add(struct ithd **ithdp, const char *name, driver_intr_t handler,
|
|
void *arg, int pri, enum intr_type flags, void **cookiep)
|
|
{
|
|
struct proc *p;
|
|
struct ithd *ithd;
|
|
int error;
|
|
|
|
if (flags & (INTR_FAST | INTR_ENTROPY))
|
|
return (EINVAL);
|
|
|
|
ithd = (ithdp != NULL) ? *ithdp : NULL;
|
|
|
|
if (ithd != NULL) {
|
|
if ((ithd->it_flags & IT_SOFT) == 0)
|
|
return(EINVAL);
|
|
} else {
|
|
error = ithread_create(&ithd, pri, IT_SOFT, NULL, NULL,
|
|
"swi%d:", pri);
|
|
if (error)
|
|
return (error);
|
|
|
|
if (ithdp != NULL)
|
|
*ithdp = ithd;
|
|
}
|
|
return (ithread_add_handler(ithd, name, handler, arg, pri + PI_SOFT,
|
|
flags, cookiep));
|
|
}
|
|
.Ed
|
|
.Sh ERRORS
|
|
The
|
|
.Fn ithread_add_handler
|
|
function will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
Any of the
|
|
.Fa ithread ,
|
|
.Fa handler ,
|
|
or
|
|
.Fa name
|
|
arguments are
|
|
.Dv NULL .
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Dv INTR_EXCL
|
|
flag is specified and the interrupt thread
|
|
.Fa ithread
|
|
already has at least one handler, or the interrupt thread
|
|
.Fa ithread
|
|
already has an exclusive handler.
|
|
.It Bq Er ENOMEM
|
|
Could not allocate needed memory for this handler.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn ithread_create
|
|
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
|
|
A flag other than
|
|
.Dv IT_SOFT
|
|
was specified in the
|
|
.Fa flags
|
|
parameter.
|
|
.It Bq Er ENOMEM
|
|
Could not allocate needed memory for this interrupt thread.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn ithread_destroy
|
|
function will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa ithread
|
|
argument is
|
|
.Dv NULL .
|
|
.It Bq Er EINVAL
|
|
The interrupt thread pointed to by
|
|
.Fa ithread
|
|
has at least one handler.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn ithread_remove_handler
|
|
function will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa cookie
|
|
argument is
|
|
.Dv NULL .
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn ithread_schedule
|
|
function will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa ithread
|
|
argument is
|
|
.Dv NULL .
|
|
.It Bq Er EINVAL
|
|
The interrupt thread pointed to by
|
|
.Fa ithread
|
|
has no interrupt handlers.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr kthread 9 ,
|
|
.Xr malloc 9 ,
|
|
.Xr swi 9 ,
|
|
.Xr uma 9
|
|
.Sh HISTORY
|
|
Interrupt threads and their corresponding API first appeared in
|
|
.Fx 5.0 .
|
|
.Sh BUGS
|
|
Currently
|
|
.Vt struct ithd
|
|
represents both an interrupt source and an interrupt thread.
|
|
There should be a separate
|
|
.Vt struct isrc
|
|
that contains a vector number, enable and disable functions, etc.\& that
|
|
an ithread holds a reference to.
|