kmdb/kctl/kctl_wr.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * Implements the kernel side of the debugger/kernel work queue.
 */

#include <kmdb/kmdb_kdi.h>
#include <kmdb/kctl/kctl.h>
#include <kmdb/kctl/kctl_wr.h>

#include <sys/proc.h>
#include <sys/disp.h>
#include <sys/kdi_impl.h>
#include <sys/callb.h>

#define KCTL_WR_PROCESS_NORMAL      (void *)0
#define KCTL_WR_PROCESS_UNLOADING   (void *)1

/*
 * Processes events from the debugger -> driver notification queue.  Returns
 * 1 if the debugger should be awakened after the queue has been processed.
 */
static int
kctl_wr_process_cb(kmdb_wr_t *wn, void *arg)
{
    int unloading = (arg == KCTL_WR_PROCESS_UNLOADING);

    switch (WR_TASK(wn)) {
    case WNTASK_DMOD_LOAD: {
        /*
         * If this is an ack, then we're getting back a message from a
         * load we initiated.  Free it.  If it's not an ack, we process
         * the message (attempt to load the requested module) and send
         * an ack back to the debugger.
         */
        kmdb_wr_load_t *dlr = (kmdb_wr_load_t *)wn;

        if (WR_ISACK(dlr)) {
            kctl_dprintf("received ack for dmod load of %s",
                dlr->dlr_fname);
            kctl_dmod_load_ack(dlr);
            return (0);
        } else
            kctl_dprintf("received dmod load request %s",
                dlr->dlr_fname);

        if (unloading) {
            /*
             * If the user didn't wait for all dmods to load before
             * she triggered the debugger unload, we may have some
             * dmod load requests on the queue in front of the
             * blizzard of dmod unload requests that the debugger
             * will generate as part of its unload.  The debugger
             * won't have generated unloads for pending dmods, so
             * we can safely ignore the load requests.
             */
            kctl_dprintf("skipping load of dmod %s due to "
                "in-process unload");
        } else
            (void) kctl_dmod_load(dlr); /* dlr will have errno */

        WR_ACK(dlr);
        kmdb_wr_debugger_notify(dlr);
        return (1);
    }

    case WNTASK_DMOD_LOAD_ALL:
        /*
         * We don't initiate all-module loads, so this can't be an
         * ack.  We process the load-all, and send the message back
         * to the driver as an ack.
         */
        ASSERT(!WR_ISACK(wn));

        kctl_dprintf("received request to load all dmods");

        (void) kctl_dmod_load_all();

        WR_ACK(wn);
        kmdb_wr_debugger_notify(wn);
        return (1);

    case WNTASK_DMOD_UNLOAD: {
        /*
         * The driver received an unload request.  We don't initiate
         * unloads, so this can't be an ack.  We process the unload,
         * and send the message back to the driver as an ack.
         */
        kmdb_wr_unload_t *dur = (kmdb_wr_unload_t *)wn;

        ASSERT(!WR_ISACK(dur));
        ASSERT(kctl.kctl_boot_ops == NULL);

        kctl_dprintf("received dmod unload message %s",
            dur->dur_modname);

        kctl_dmod_unload(dur);

        WR_ACK(dur);
        kmdb_wr_debugger_notify(dur);
        return (1);
    }

    case WNTASK_DMOD_PATH_CHANGE: {
        /*
         * We don't initiate path changes, so this can't be an ack.
         * This request type differs from the others in that we only
         * return it (as an ack) when we're done with it.  We're only
         * done with it when we receive another one, or when the
         * debugger is unloading.
         */
        kmdb_wr_path_t *pth = (kmdb_wr_path_t *)wn;
        kmdb_wr_path_t *opth;

        ASSERT(!WR_ISACK(pth));

        kctl_dprintf("received path change message");

        if ((opth = kctl_dmod_path_set(pth)) != NULL) {
            /* We have an old path request to return */
            WR_ACK(opth);
            kmdb_wr_debugger_notify(opth);

            /*
             * The debugger can process the returned path change
             * request at its leisure
             */
            return (0);
        }

        /* Nothing to do */
        return (0);
    }

    default:
        cmn_err(CE_WARN, "Received unknown work request %d from kmdb\n",
            wn->wn_task);
        /* Drop message */
        return (0);
    }

    /*NOTREACHED*/
}

int
kctl_wr_process(void)
{
    return (kmdb_wr_driver_process(kctl_wr_process_cb,
        KCTL_WR_PROCESS_NORMAL));
}

/*
 * Catches the "work to do" soft interrupt, and passes the notification along
 * to the worker thread.
 */
/*ARGSUSED*/
void
kctl_wrintr(void)
{
    kctl.kctl_wr_avail = 0;

    sema_v(&kctl.kctl_wr_avail_sem);
}

/*
 * This routine is called by the debugger while the world is resuming.
 */
void
kctl_wrintr_fire(void)
{
    kctl.kctl_wr_avail = 1;

    kdi_softcall(kctl_wrintr);
}

/*
 * Given the possibility of asynchronous unload, the locking semantics are
 * somewhat tricky.  See kctl_main.c
 */
/*ARGSUSED*/
static void
kctl_wr_thread(void *arg)
{
    callb_cpr_t cprinfo;
    kmutex_t cprlock;

    mutex_init(&cprlock, NULL, MUTEX_DEFAULT, NULL);
    CALLB_CPR_INIT(&cprinfo, &cprlock, callb_generic_cpr, "kmdb work");

    for (;;) {
        /*
         * XXX what should I do here for panic?  It'll spin unless I
         * can figure out a way to park it.  Presumably I don't want to
         * let it exit.
         */
        mutex_enter(&cprlock);
        CALLB_CPR_SAFE_BEGIN(&cprinfo);
        mutex_exit(&cprlock);

        sema_p(&kctl.kctl_wr_avail_sem);

        mutex_enter(&cprlock);
        CALLB_CPR_SAFE_END(&cprinfo, &cprlock);
        mutex_exit(&cprlock);

        kctl_dprintf("kctl worker thread - waking up");

        if (kmdb_kdi_get_unload_request() ||
            kctl.kctl_wr_state != KCTL_WR_ST_RUN) {
            /*
             * We've either got a debugger-initiated unload (if
             * unload_request returned true), or we're stopping due
             * to an error discovered by the driver (if
             * kctl_worker_run is no longer non-zero).  Start
             * cleaning up.
             */

            /*
             * The debugger has already deactivated itself, and will
             * have dumped a bunch of stuff on the queue.  We need
             * to process it before exiting.
             */
            (void) kmdb_wr_driver_process(kctl_wr_process_cb,
                KCTL_WR_PROCESS_UNLOADING);
            break;
        }

        /*
         * A non-zero return means we've passed messages back to the
         * debugger for processing, so we need to wake the debugger up.
         */
        if (kctl_wr_process() > 0)
            kmdb_kdi_kmdb_enter();
    }

    /*
     * NULL out the dmod search path, so we can send the current one back
     * to the debugger.  XXX this should probably be somewhere else.
     */
    kctl_dmod_path_reset();

    /*
     * The debugger will send us unload notifications for each dmod that it
     * noticed.  If, for example, the debugger is unloaded before the first
     * start, it won't have noticed any of the dmods we loaded.  We'll need
     * to initiate the unloads ourselves.
     */
    kctl_dmod_unload_all();

    kctl.kctl_wr_state = KCTL_WR_ST_STOPPED;

    /*
     * Must be last, as it concludes by setting state to INACTIVE.  The
     * kctl data structure must not be accessed by this thread after that
     * point.
     */
    kctl_cleanup();

    mutex_enter(&cprlock);
    CALLB_CPR_EXIT(&cprinfo);
    mutex_destroy(&cprlock);
}

void
kctl_wr_thr_start(void)
{
    kctl.kctl_wr_avail = 0;
    kctl.kctl_wr_state = KCTL_WR_ST_RUN;
    kctl.kctl_wr_thr = thread_create(NULL, 0, kctl_wr_thread, NULL, 0, &p0,
        TS_RUN, minclsyspri);
}

void
kctl_wr_thr_stop(void)
{
    ASSERT(kctl.kctl_wr_state == KCTL_WR_ST_RUN);
    kctl.kctl_wr_state = KCTL_WR_ST_STOP;
    sema_v(&kctl.kctl_wr_avail_sem);
}

void
kctl_wr_thr_join(void)
{
    thread_join(kctl.kctl_wr_thr->t_did);
}