common/os/softint.c

	softint.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/param.h>
#include <sys/t_lock.h>
#include <sys/systm.h>
#include <sys/spl.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/kdi_impl.h>

/*
 * Handle software interrupts through 'softcall' mechanism
 */

#define NSOFTCALLS  200

typedef struct softcall {
    void (*sc_func)(void *);    /* function to call */
    void *sc_arg;           /* arg to pass to func */
    struct softcall *sc_next;   /* next in list */
} softcall_t;

static softcall_t softcalls[NSOFTCALLS], *softhead, *softtail, *softfree;

static kmutex_t softcall_lock;      /* protects softcall lists */

static void (*kdi_softcall_func)(void);

extern void siron(void);

void
softcall_init(void)
{
    softcall_t *sc;

    for (sc = softcalls; sc < &softcalls[NSOFTCALLS]; sc++) {
        sc->sc_next = softfree;
        softfree = sc;
    }
    mutex_init(&softcall_lock, NULL, MUTEX_SPIN, (void *)ipltospl(SPL8));
}

/*
 * Call function func with argument arg
 * at some later time at software interrupt priority
 */
void
softcall(void (*func)(void *), void *arg)
{
    softcall_t *sc;

    /*
     * protect against cross-calls
     */
    mutex_enter(&softcall_lock);
    /* coalesce identical softcalls */
    for (sc = softhead; sc != 0; sc = sc->sc_next) {
        if (sc->sc_func == func && sc->sc_arg == arg) {
            mutex_exit(&softcall_lock);
            return;
        }
    }

    if ((sc = softfree) == 0)
        panic("too many softcalls");
    softfree = sc->sc_next;
    sc->sc_func = func;
    sc->sc_arg = arg;
    sc->sc_next = 0;

    if (softhead) {
        softtail->sc_next = sc;
        softtail = sc;
        mutex_exit(&softcall_lock);
    } else {
        softhead = softtail = sc;
        mutex_exit(&softcall_lock);
        siron();
    }
}

void
kdi_softcall(void (*func)(void))
{
    kdi_softcall_func = func;

    if (softhead == NULL)
        siron();
}

/*
 * Called to process software interrupts
 * take one off queue, call it, repeat
 * Note queue may change during call
 */
void
softint(void)
{
    softcall_t *sc;
    void (*func)();
    caddr_t arg;

    for (;;) {
        mutex_enter(&softcall_lock);
        if ((sc = softhead) != NULL) {
            func = sc->sc_func;
            arg = sc->sc_arg;
            softhead = sc->sc_next;
            sc->sc_next = softfree;
            softfree = sc;
        }
        mutex_exit(&softcall_lock);
        if (sc == NULL)
            break;
        func(arg);
    }

    if ((func = kdi_softcall_func) != NULL) {
        kdi_softcall_func = NULL;
        func();
    }
}