serengeti/io/sbdp_quiesce.c

	sbdp_quiesce.c revision 03831d35f7499c87d51205817c93e9a8d42c4bae
/*
 * 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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * A CPR derivative specifically for sbd
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/machparam.h>
#include <sys/machsystm.h>
#include <sys/ddi.h>
#define SUNDDI_IMPL
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/devctl.h>
#include <sys/time.h>
#include <sys/kmem.h>
#include <nfs/lm.h>
#include <sys/ddi_impldefs.h>
#include <sys/ndi_impldefs.h>
#include <sys/obpdefs.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/callb.h>
#include <sys/clock.h>
#include <sys/x_call.h>
#include <sys/cpuvar.h>
#include <sys/epm.h>
#include <sys/vfs.h>

#ifdef DEBUG
#include <sys/note.h>
#endif

#include <sys/promif.h>
#include <sys/conf.h>
#include <sys/cyclic.h>

#include <sys/sbd_ioctl.h>
#include <sys/sbd.h>
#include <sys/sbdp_priv.h>
#include <sys/cpu_sgnblk_defs.h>

static char *
sbdp_get_err_buf(sbd_error_t *ep)
{
    return (ep->e_rsc);
}

extern void e_ddi_enter_driver_list(struct devnames *dnp, int *listcnt);
extern void e_ddi_exit_driver_list(struct devnames *dnp, int listcnt);
extern int  is_pseudo_device(dev_info_t *dip);

extern kmutex_t cpu_lock;

static int  sbdp_is_real_device(dev_info_t *dip);
#ifdef DEBUG
static int  sbdp_bypass_device(char *dname);
#endif
static int  sbdp_check_dip(dev_info_t *dip, void *arg, uint_t ref);

static int  sbdp_resolve_devname(dev_info_t *dip, char *buffer,
                char *alias);

int sbdp_test_suspend(sbdp_handle_t *hp);

#define SR_STATE(srh)           ((srh)->sr_suspend_state)
#define SR_SET_STATE(srh, state)    (SR_STATE((srh)) = (state))
#define SR_FAILED_DIP(srh)      ((srh)->sr_failed_dip)

#define SR_FLAG_WATCHDOG    0x1
#define SR_CHECK_FLAG(srh, flag)    ((srh)->sr_flags & (flag))
#define SR_SET_FLAG(srh, flag)      ((srh)->sr_flags |= (flag))
#define SR_CLEAR_FLAG(srh, flag)    ((srh)->sr_flags &= ~(flag))

#ifdef DEBUG
/*
 * Just for testing. List of drivers to bypass when performing a suspend.
 */
static char *sbdp_bypass_list[] = {
    /* "sgsbbc", this is an example when needed */
    ""
};
#endif

#define     SKIP_SYNC   /* bypass sync ops in sbdp_suspend */

/*
 * sbdp_skip_user_threads is used to control if user threads should
 * be suspended.  If sbdp_skip_user_threads is true, the rest of the
 * flags are not used; if it is false, sbdp_check_user_stop_result
 * will be used to control whether or not we need to check suspend
 * result, and sbdp_allow_blocked_threads will be used to control
 * whether or not we allow suspend to continue if there are blocked
 * threads.  We allow all combinations of sbdp_check_user_stop_result
 * and sbdp_allow_block_threads, even though it might not make much
 * sense to not allow block threads when we don't even check stop
 * result.
 */
static int  sbdp_skip_user_threads = 0;     /* default to FALSE */
static int  sbdp_check_user_stop_result = 1;    /* default to TRUE */
static int  sbdp_allow_blocked_threads = 1;     /* default to TRUE */


static void
sbdp_stop_intr(void)
{
    kpreempt_disable();
    cyclic_suspend();
}

static void
sbdp_enable_intr(void)
{
    cyclic_resume();
    kpreempt_enable();
}

sbdp_sr_handle_t *
sbdp_get_sr_handle(void)
{
    sbdp_sr_handle_t *srh;
    srh = kmem_zalloc(sizeof (sbdp_sr_handle_t), KM_SLEEP);

    return (srh);
}

void
sbdp_release_sr_handle(sbdp_sr_handle_t *srh)
{
    ASSERT(SR_FAILED_DIP(srh) == NULL);
    kmem_free((caddr_t)srh, sizeof (sbdp_sr_handle_t));
}

static int
sbdp_is_real_device(dev_info_t *dip)
{
    struct regspec *regbuf = NULL;
    int length = 0;
    int rc;

    if (ddi_get_driver(dip) == NULL)
        return (0);

    if (DEVI(dip)->devi_pm_flags & (PMC_NEEDS_SR|PMC_PARENTAL_SR))
        return (1);
    if (DEVI(dip)->devi_pm_flags & PMC_NO_SR)
        return (0);

    /*
     * now the general case
     */
    rc = ddi_getlongprop(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS, "reg",
        (caddr_t)&regbuf, &length);
    ASSERT(rc != DDI_PROP_NO_MEMORY);
    if (rc != DDI_PROP_SUCCESS) {
        return (0);
    } else {
        if ((length > 0) && (regbuf != NULL))
            kmem_free(regbuf, length);
        return (1);
    }
}

#ifdef DEBUG
static int
sbdp_bypass_device(char *dname)
{
    int i;
    char **lname;
    /* check the bypass list */
    for (i = 0, lname = &sbdp_bypass_list[i]; **lname != '\0'; lname++) {
        SBDP_DBG_QR("Checking %s\n", *lname);
        if (strcmp(dname, sbdp_bypass_list[i++]) == 0)
            return (1);
    }
    return (0);
}
#endif

static int
sbdp_resolve_devname(dev_info_t *dip, char *buffer, char *alias)
{
    major_t devmajor;
    char    *aka, *name;

    *buffer = *alias = 0;

    if (dip == NULL)
        return (-1);

    if ((name = ddi_get_name(dip)) == NULL)
        name = "<null name>";

    aka = name;

    if ((devmajor = ddi_name_to_major(aka)) != -1)
        aka = ddi_major_to_name(devmajor);

    (void) strcpy(buffer, name);

    if (strcmp(name, aka))
        (void) strcpy(alias, aka);
    else
        *alias = 0;

    return (0);
}

typedef struct sbdp_ref {
    int *refcount;
    sbd_error_t *sep;
} sbdp_ref_t;

static int
sbdp_check_dip(dev_info_t *dip, void *arg, uint_t ref)
{
    char        *dname;
    sbdp_ref_t  *sbrp = (sbdp_ref_t *)arg;

    if (dip == NULL)
        return (DDI_WALK_CONTINUE);

    ASSERT(sbrp->sep != NULL);
    ASSERT(sbrp->refcount != NULL);

    if (!sbdp_is_real_device(dip))
        return (DDI_WALK_CONTINUE);

    dname = ddi_binding_name(dip);

    if ((strcmp(dname, "pciclass,060940") == 0) || (strcmp(dname,
        "pciclass,060980") == 0)) {
        (void) ddi_pathname(dip, sbdp_get_err_buf(sbrp->sep));
        sbdp_set_err(sbrp->sep, ESBD_BUSY, NULL);
        (*sbrp->refcount)++;
        return (DDI_WALK_TERMINATE);
    }

#ifdef DEBUG
    if (sbdp_bypass_device(dname))
        return (DDI_WALK_CONTINUE);
#endif

    if (ref) {
        (*sbrp->refcount)++;
        SBDP_DBG_QR("\n%s (major# %d) is referenced\n",
            dname, ddi_name_to_major(dname));
        (void) ddi_pathname(dip, sbdp_get_err_buf(sbrp->sep));
        sbdp_set_err(sbrp->sep, ESBD_BUSY, NULL);
        return (DDI_WALK_TERMINATE);
    }
    return (DDI_WALK_CONTINUE);
}

void
sbdp_check_devices(dev_info_t *dip, int *refcount, sbd_error_t *sep)
{
    sbdp_ref_t sbr;

    sbr.refcount = refcount;
    sbr.sep = sep;

    ASSERT(e_ddi_branch_held(dip));

    (void) e_ddi_branch_referenced(dip, sbdp_check_dip, &sbr);
}

static int
sbdp_suspend_devices(dev_info_t *dip, sbdp_sr_handle_t *srh)
{
    int circ;
    major_t major;
    char    *dname;

    for (; dip != NULL; dip = ddi_get_next_sibling(dip)) {
        char    d_name[40], d_alias[40], *d_info;

        ndi_devi_enter(dip, &circ);
        if (sbdp_suspend_devices(ddi_get_child(dip), srh)) {
            ndi_devi_exit(dip, circ);
            return (ENXIO);
        }
        ndi_devi_exit(dip, circ);

        if (!sbdp_is_real_device(dip))
                continue;

        major = (major_t)-1;
        if ((dname = DEVI(dip)->devi_binding_name) != NULL)
            major = ddi_name_to_major(dname);

#ifdef DEBUG
        if (sbdp_bypass_device(dname)) {
            SBDP_DBG_QR("bypassed suspend of %s (major# %d)\n",
                dname, major);
            continue;
        }
#endif

        if ((d_info = ddi_get_name_addr(dip)) == NULL)
            d_info = "<null>";

        d_name[0] = 0;
        if (sbdp_resolve_devname(dip, d_name, d_alias) == 0) {
            if (d_alias[0] != 0) {
                SBDP_DBG_QR("\tsuspending %s@%s (aka %s)\n",
                    d_name, d_info, d_alias);
            } else {
                SBDP_DBG_QR("\tsuspending %s@%s\n",
                    d_name, d_info);
            }
        } else {
            SBDP_DBG_QR("\tsuspending %s@%s\n", dname, d_info);
        }

        if (devi_detach(dip, DDI_SUSPEND) != DDI_SUCCESS) {
            (void) sprintf(sbdp_get_err_buf(&srh->sep),
                "%d", major);

            sbdp_set_err(&srh->sep, ESGT_SUSPEND, NULL);
            ndi_hold_devi(dip);
            SR_FAILED_DIP(srh) = dip;
            return (DDI_FAILURE);
        }
    }

    return (DDI_SUCCESS);
}

static void
sbdp_resume_devices(dev_info_t *start, sbdp_sr_handle_t *srh)
{
    int circ;
    dev_info_t  *dip, *next, *last = NULL;
    char        *bn;
    sbd_error_t *sep;

    sep = &srh->sep;

    /* attach in reverse device tree order */
    while (last != start) {
        dip = start;
        next = ddi_get_next_sibling(dip);
        while (next != last && dip != SR_FAILED_DIP(srh)) {
            dip = next;
            next = ddi_get_next_sibling(dip);
        }
        if (dip == SR_FAILED_DIP(srh)) {
            /* Release hold acquired in sbdp_suspend_devices() */
            ndi_rele_devi(dip);
            SR_FAILED_DIP(srh) = NULL;
        } else if (sbdp_is_real_device(dip) &&
                SR_FAILED_DIP(srh) == NULL) {

            if (DEVI(dip)->devi_binding_name != NULL) {
                bn = ddi_binding_name(dip);
            }
#ifdef DEBUG
            if (!sbdp_bypass_device(bn)) {
#else
            {
#endif
                char    d_name[40], d_alias[40], *d_info;

                d_name[0] = 0;
                d_info = ddi_get_name_addr(dip);
                if (d_info == NULL)
                    d_info = "<null>";

                if (!sbdp_resolve_devname(dip, d_name,
                                d_alias)) {
                    if (d_alias[0] != 0) {
                        SBDP_DBG_QR("\tresuming "
                            "%s@%s (aka %s)\n",
                            d_name, d_info,
                            d_alias);
                    } else {
                        SBDP_DBG_QR("\tresuming "
                            "%s@%s\n",
                            d_name, d_info);
                    }
                } else {
                    SBDP_DBG_QR("\tresuming %s@%s\n",
                        bn, d_info);
                }

                if (devi_attach(dip, DDI_RESUME) !=
                            DDI_SUCCESS) {
                    /*
                     * Print a console warning,
                     * set an errno of ESGT_RESUME,
                     * and save the driver major
                     * number in the e_str.
                     */

                    (void) sprintf(sbdp_get_err_buf(sep),
                        "%s@%s",
                        d_name[0] ? d_name : bn, d_info);
                    SBDP_DBG_QR("\tFAILED to resume "
                        "%s\n", sbdp_get_err_buf(sep));
                    sbdp_set_err(sep,
                        ESGT_RESUME, NULL);
                }
            }
        }
        ndi_devi_enter(dip, &circ);
        sbdp_resume_devices(ddi_get_child(dip), srh);
        ndi_devi_exit(dip, circ);
        last = dip;
    }
}

/*
 * True if thread is virtually stopped.  Similar to CPR_VSTOPPED
 * but from DR point of view.  These user threads are waiting in
 * the kernel.  Once they return from kernel, they will process
 * the stop signal and stop.
 */
#define SBDP_VSTOPPED(t)            \
    ((t)->t_state == TS_SLEEP &&        \
    (t)->t_wchan != NULL &&         \
    (t)->t_astflag &&       \
    ((t)->t_proc_flag & TP_CHKPT))


static int
sbdp_stop_user_threads(sbdp_sr_handle_t *srh)
{
    int     count;
    char        cache_psargs[PSARGSZ];
    kthread_id_t    cache_tp;
    uint_t      cache_t_state;
    int     bailout;
    sbd_error_t *sep;
    kthread_id_t    tp;

    extern void add_one_utstop();
    extern void utstop_timedwait(clock_t);
    extern void utstop_init(void);

#define SBDP_UTSTOP_RETRY   4
#define SBDP_UTSTOP_WAIT    hz

    if (sbdp_skip_user_threads)
        return (DDI_SUCCESS);

    sep = &srh->sep;
    ASSERT(sep);

    utstop_init();

    /* we need to try a few times to get past fork, etc. */
    for (count = 0; count < SBDP_UTSTOP_RETRY; count++) {
        /* walk the entire threadlist */
        mutex_enter(&pidlock);
        for (tp = curthread->t_next; tp != curthread; tp = tp->t_next) {
            proc_t *p = ttoproc(tp);

            /* handle kernel threads separately */
            if (p->p_as == &kas || p->p_stat == SZOMB)
                continue;

            mutex_enter(&p->p_lock);
            thread_lock(tp);

            if (tp->t_state == TS_STOPPED) {
                /* add another reason to stop this thread */
                tp->t_schedflag &= ~TS_RESUME;
            } else {
                tp->t_proc_flag |= TP_CHKPT;

                thread_unlock(tp);
                mutex_exit(&p->p_lock);
                add_one_utstop();
                mutex_enter(&p->p_lock);
                thread_lock(tp);

                aston(tp);

                if (tp->t_state == TS_SLEEP &&
                    (tp->t_flag & T_WAKEABLE)) {
                    setrun_locked(tp);
                }

            }

            /* grab thread if needed */
            if (tp->t_state == TS_ONPROC && tp->t_cpu != CPU)
                poke_cpu(tp->t_cpu->cpu_id);


            thread_unlock(tp);
            mutex_exit(&p->p_lock);
        }
        mutex_exit(&pidlock);


        /* let everything catch up */
        utstop_timedwait(count * count * SBDP_UTSTOP_WAIT);


        /* now, walk the threadlist again to see if we are done */
        mutex_enter(&pidlock);
        for (tp = curthread->t_next, bailout = 0;
            tp != curthread; tp = tp->t_next) {
            proc_t *p = ttoproc(tp);

            /* handle kernel threads separately */
            if (p->p_as == &kas || p->p_stat == SZOMB)
                continue;

            /*
             * If this thread didn't stop, and we don't allow
             * unstopped blocked threads, bail.
             */
            thread_lock(tp);
            if (!CPR_ISTOPPED(tp) &&
                !(sbdp_allow_blocked_threads &&
                SBDP_VSTOPPED(tp))) {

                /* nope, cache the details for later */
                bcopy(p->p_user.u_psargs, cache_psargs,
                    sizeof (cache_psargs));
                cache_tp = tp;
                cache_t_state = tp->t_state;
                bailout = 1;
            }
            thread_unlock(tp);
        }
        mutex_exit(&pidlock);

        /* were all the threads stopped? */
        if (!bailout)
            break;
    }

    /* were we unable to stop all threads after a few tries? */
    if (bailout) {
        cmn_err(CE_NOTE, "process: %s id: %p state: %x\n",
            cache_psargs, cache_tp, cache_t_state);

        (void) sprintf(sbdp_get_err_buf(sep), "%s", cache_psargs);
        sbdp_set_err(sep, ESGT_UTHREAD, NULL);
        return (ESRCH);
    }

    return (DDI_SUCCESS);
}

static void
sbdp_start_user_threads(void)
{
    kthread_id_t tp;

    mutex_enter(&pidlock);

    /* walk all threads and release them */
    for (tp = curthread->t_next; tp != curthread; tp = tp->t_next) {
        proc_t *p = ttoproc(tp);

        /* skip kernel threads */
        if (ttoproc(tp)->p_as == &kas)
            continue;

        mutex_enter(&p->p_lock);
        tp->t_proc_flag &= ~TP_CHKPT;
        mutex_exit(&p->p_lock);

        thread_lock(tp);
        if (CPR_ISTOPPED(tp)) {
            /* back on the runq */
            tp->t_schedflag |= TS_RESUME;
            setrun_locked(tp);
        }
        thread_unlock(tp);
    }

    mutex_exit(&pidlock);
}

static void
sbdp_signal_user(int sig)
{
    struct proc *p;

    mutex_enter(&pidlock);

    for (p = practive; p != NULL; p = p->p_next) {
        /* only user threads */
        if (p->p_exec == NULL || p->p_stat == SZOMB ||
            p == proc_init || p == ttoproc(curthread))
            continue;

        mutex_enter(&p->p_lock);
        sigtoproc(p, NULL, sig);
        mutex_exit(&p->p_lock);
    }

    mutex_exit(&pidlock);

    /* add a bit of delay */
    delay(hz);
}

static uint_t saved_watchdog_seconds;

void
sbdp_resume(sbdp_sr_handle_t *srh)
{
    /*
     * update the signature block
     */
    CPU_SIGNATURE(OS_SIG, SIGST_RESUME_INPROGRESS, SIGSUBST_NULL,
        CPU->cpu_id);

    switch (SR_STATE(srh)) {
    case SBDP_SRSTATE_FULL:

        ASSERT(MUTEX_HELD(&cpu_lock));

        sbdp_enable_intr();     /* enable intr & clock */

        /*
         * release all the other cpus
         * using start_cpus() vice sbdp_release_cpus()
         */
        start_cpus();
        mutex_exit(&cpu_lock);

        /*
         * If we suspended hw watchdog at suspend,
         * re-enable it now.
         */

        if (SR_CHECK_FLAG(srh, SR_FLAG_WATCHDOG)) {
            mutex_enter(&tod_lock);
            tod_ops.tod_set_watchdog_timer(
                saved_watchdog_seconds);
            mutex_exit(&tod_lock);
        }

        /* FALLTHROUGH */

    case SBDP_SRSTATE_DRIVER:
        /*
         * resume devices: root node doesn't have to
         * be held in any way.
         */
        sbdp_resume_devices(ddi_root_node(), srh);

        /*
         * resume the lock manager
         */
        lm_cprresume();

        /* FALLTHROUGH */

    case SBDP_SRSTATE_USER:
        /*
         * finally, resume user threads
         */
        if (!sbdp_skip_user_threads) {
            SBDP_DBG_QR("DR: resuming user threads...\n");
            sbdp_start_user_threads();
        }
        /* FALLTHROUGH */

    case SBDP_SRSTATE_BEGIN:
    default:
        /*
         * let those who care know that we've just resumed
         */
        SBDP_DBG_QR("sending SIGTHAW...\n");
        sbdp_signal_user(SIGTHAW);
        break;
    }

    i_ndi_allow_device_tree_changes(srh->sh_ndi);

    /*
     * update the signature block
     */
    CPU_SIGNATURE(OS_SIG, SIGST_RUN, SIGSUBST_NULL, CPU->cpu_id);

    SBDP_DBG_QR("DR: resume COMPLETED\n");
}

int
sbdp_suspend(sbdp_sr_handle_t *srh)
{
    int force;
    int rc = DDI_SUCCESS;

    force = (srh && (srh->sr_flags & SBDP_IOCTL_FLAG_FORCE));

    /*
     * if no force flag, check for unsafe drivers
     */
    if (force) {
        SBDP_DBG_QR("\nsbdp_suspend invoked with force flag");
    }

    /*
     * update the signature block
     */
    CPU_SIGNATURE(OS_SIG, SIGST_QUIESCE_INPROGRESS, SIGSUBST_NULL,
        CPU->cpu_id);

    i_ndi_block_device_tree_changes(&srh->sh_ndi);

    /*
     * first, stop all user threads
     */
    SBDP_DBG_QR("SBDP: suspending user threads...\n");
    SR_SET_STATE(srh, SBDP_SRSTATE_USER);
    if (((rc = sbdp_stop_user_threads(srh)) != DDI_SUCCESS) &&
        sbdp_check_user_stop_result) {
        sbdp_resume(srh);
        return (rc);
    }

#ifndef SKIP_SYNC
    /*
     * This sync swap out all user pages
     */
    vfs_sync(SYNC_ALL);
#endif

    /*
     * special treatment for lock manager
     */
    lm_cprsuspend();

#ifndef SKIP_SYNC
    /*
     * sync the file system in case we never make it back
     */
    sync();

#endif
    /*
     * now suspend drivers
     */
    SBDP_DBG_QR("SBDP: suspending drivers...\n");
    SR_SET_STATE(srh, SBDP_SRSTATE_DRIVER);

    /*
     * Root node doesn't have to be held in any way.
     */
    if ((rc = sbdp_suspend_devices(ddi_root_node(), srh)) != DDI_SUCCESS) {
        sbdp_resume(srh);
        return (rc);
    }

    /*
     * finally, grab all cpus
     */
    SR_SET_STATE(srh, SBDP_SRSTATE_FULL);

    /*
     * if watchdog was activated, disable it
     */
    if (watchdog_activated) {
        mutex_enter(&tod_lock);
        saved_watchdog_seconds = tod_ops.tod_clear_watchdog_timer();
        mutex_exit(&tod_lock);
        SR_SET_FLAG(srh, SR_FLAG_WATCHDOG);
    } else {
        SR_CLEAR_FLAG(srh, SR_FLAG_WATCHDOG);
    }

    mutex_enter(&cpu_lock);
    pause_cpus(NULL);
    sbdp_stop_intr();

    /*
     * update the signature block
     */
    CPU_SIGNATURE(OS_SIG, SIGST_QUIESCED, SIGSUBST_NULL, CPU->cpu_id);

    return (rc);
}

/*ARGSUSED*/
int
sbdp_test_suspend(sbdp_handle_t *hp)
{
    sbdp_sr_handle_t    *srh;
    int         err;

    SBDP_DBG_QR("%s...\n", "sbdp_test_suspend");

    srh = sbdp_get_sr_handle();

    srh->sr_flags = hp->h_flags;

    if ((err = sbdp_suspend(srh)) == DDI_SUCCESS) {
        sbdp_resume(srh);
    } else {
        SBDP_DBG_MISC("sbdp_suspend() failed, err = 0x%x\n", err);
    }
    sbdp_release_sr_handle(srh);

    return (0);
}

#ifdef  DEBUG
int
sbdp_passthru_test_quiesce(sbdp_handle_t *hp, void *arg)
{
    _NOTE(ARGUNUSED(arg))

    return (sbdp_test_suspend(hp));
}
#endif