5285 pass in cpu_pause_func via pause_cpus

[unleashed.git] / usr / src / uts / sun4u / ngdr / io / dr_quiesce.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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * A CPR derivative specifically for starfire/starcat
 */

#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>

#include <sys/cpu_sgnblk_defs.h>
#include <sys/dr.h>
#include <sys/dr_util.h>

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

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;
extern dr_unsafe_devs_t dr_unsafe_devs;

static int              dr_is_real_device(dev_info_t *dip);
static int              dr_is_unsafe_major(major_t major);
static int              dr_bypass_device(char *dname);
static int              dr_check_dip(dev_info_t *dip, void *arg, uint_t ref);
static int              dr_resolve_devname(dev_info_t *dip, char *buffer,
                                char *alias);
static sbd_error_t      *drerr_int(int e_code, uint64_t *arr, int idx,
                                int majors);
static int              dr_add_int(uint64_t *arr, int idx, int len,
                                uint64_t val);

int dr_pt_test_suspend(dr_handle_t *hp);

/*
 * dr_quiesce.c interface
 * NOTE: states used internally by dr_suspend and dr_resume
 */
typedef enum dr_suspend_state {
        DR_SRSTATE_BEGIN = 0,
        DR_SRSTATE_USER,
        DR_SRSTATE_DRIVER,
        DR_SRSTATE_FULL
} suspend_state_t;

struct dr_sr_handle {
        dr_handle_t             *sr_dr_handlep;
        dev_info_t              *sr_failed_dip;
        suspend_state_t         sr_suspend_state;
        uint_t                  sr_flags;
        uint64_t                sr_err_ints[DR_MAX_ERR_INT];
        int                     sr_err_idx;
};

#define SR_FLAG_WATCHDOG        0x1

/*
 * XXX
 * This hack will go away before RTI.  Just for testing.
 * List of drivers to bypass when performing a suspend.
 */
static char *dr_bypass_list[] = {
        ""
};


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

/*
 * dr_skip_user_threads is used to control if user threads should
 * be suspended.  If dr_skip_user_threads is true, the rest of the
 * flags are not used; if it is false, dr_check_user_stop_result
 * will be used to control whether or not we need to check suspend
 * result, and dr_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 dr_check_user_stop_result
 * and dr_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      dr_skip_user_threads = 0;       /* default to FALSE */
static int      dr_check_user_stop_result = 1;  /* default to TRUE */
static int      dr_allow_blocked_threads = 1;   /* default to TRUE */

#define DR_CPU_LOOP_MSEC        1000

static void
dr_stop_intr(void)
{
        ASSERT(MUTEX_HELD(&cpu_lock));

        kpreempt_disable();
        cyclic_suspend();
}

static void
dr_enable_intr(void)
{
        ASSERT(MUTEX_HELD(&cpu_lock));

        cyclic_resume();
        kpreempt_enable();
}

dr_sr_handle_t *
dr_get_sr_handle(dr_handle_t *hp)
{
        dr_sr_handle_t *srh;

        srh = GETSTRUCT(dr_sr_handle_t, 1);
        srh->sr_dr_handlep = hp;

        return (srh);
}

void
dr_release_sr_handle(dr_sr_handle_t *srh)
{
        ASSERT(srh->sr_failed_dip == NULL);
        FREESTRUCT(srh, dr_sr_handle_t, 1);
}

static int
dr_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);
        }
}

static int
dr_is_unsafe_major(major_t major)
{
        char    *dname, **cpp;
        int     i, ndevs;

        if ((dname = ddi_major_to_name(major)) == NULL) {
                PR_QR("dr_is_unsafe_major: invalid major # %d\n", major);
                return (0);
        }

        ndevs = dr_unsafe_devs.ndevs;
        for (i = 0, cpp = dr_unsafe_devs.devnames; i < ndevs; i++) {
                if (strcmp(dname, *cpp++) == 0)
                        return (1);
        }
        return (0);
}

static int
dr_bypass_device(char *dname)
{
        int i;
        char **lname;

        if (dname == NULL)
                return (0);

        /* check the bypass list */
        for (i = 0, lname = &dr_bypass_list[i]; **lname != '\0'; lname++) {
                if (strcmp(dname, dr_bypass_list[i++]) == 0)
                        return (1);
        }
        return (0);
}

static int
dr_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);
}

struct dr_ref {
        int             *refcount;
        int             *refcount_non_gldv3;
        uint64_t        *arr;
        int             *idx;
        int             len;
};

/* ARGSUSED */
static int
dr_check_dip(dev_info_t *dip, void *arg, uint_t ref)
{
        major_t         major;
        char            *dname;
        struct dr_ref   *rp = (struct dr_ref *)arg;

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

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

        dname = ddi_binding_name(dip);

        if (dr_bypass_device(dname))
                return (DDI_WALK_CONTINUE);

        if (dname && ((major = ddi_name_to_major(dname)) != (major_t)-1)) {
                if (ref && rp->refcount) {
                        *rp->refcount += ref;
                        PR_QR("\n  %s (major# %d) is referenced(%u)\n", dname,
                            major, ref);
                }
                if (ref && rp->refcount_non_gldv3) {
                        if (NETWORK_PHYSDRV(major) && !GLDV3_DRV(major))
                                *rp->refcount_non_gldv3 += ref;
                }
                if (dr_is_unsafe_major(major) && i_ddi_devi_attached(dip)) {
                        PR_QR("\n  %s (major# %d) not hotpluggable\n", dname,
                            major);
                        if (rp->arr != NULL && rp->idx != NULL)
                                *rp->idx = dr_add_int(rp->arr, *rp->idx,
                                    rp->len, (uint64_t)major);
                }
        }
        return (DDI_WALK_CONTINUE);
}

static int
dr_check_unsafe_major(dev_info_t *dip, void *arg)
{
        return (dr_check_dip(dip, arg, 0));
}


/*ARGSUSED*/
void
dr_check_devices(dev_info_t *dip, int *refcount, dr_handle_t *handle,
    uint64_t *arr, int *idx, int len, int *refcount_non_gldv3)
{
        struct dr_ref bref = {0};

        if (dip == NULL)
                return;

        bref.refcount = refcount;
        bref.refcount_non_gldv3 = refcount_non_gldv3;
        bref.arr = arr;
        bref.idx = idx;
        bref.len = len;

        ASSERT(e_ddi_branch_held(dip));
        (void) e_ddi_branch_referenced(dip, dr_check_dip, &bref);
}

/*
 * The "dip" argument's parent (if it exists) must be held busy.
 */
static int
dr_suspend_devices(dev_info_t *dip, dr_sr_handle_t *srh)
{
        dr_handle_t     *handle;
        major_t         major;
        char            *dname;
        int             circ;

        /*
         * If dip is the root node, it has no siblings and it is
         * always held. If dip is not the root node, dr_suspend_devices()
         * will be invoked with the parent held busy.
         */
        for (; dip != NULL; dip = ddi_get_next_sibling(dip)) {
                char    d_name[40], d_alias[40], *d_info;

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

                if (!dr_is_real_device(dip))
                        continue;

                major = (major_t)-1;
                if ((dname = ddi_binding_name(dip)) != NULL)
                        major = ddi_name_to_major(dname);

                if (dr_bypass_device(dname)) {
                        PR_QR(" bypassed suspend of %s (major# %d)\n", dname,
                            major);
                        continue;
                }

                if (drmach_verify_sr(dip, 1)) {
                        PR_QR(" bypassed suspend of %s (major# %d)\n", dname,
                            major);
                        continue;
                }

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

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

                if (devi_detach(dip, DDI_SUSPEND) != DDI_SUCCESS) {
                        prom_printf("\tFAILED to suspend %s@%s\n",
                            d_name[0] ? d_name : dname, d_info);

                        srh->sr_err_idx = dr_add_int(srh->sr_err_ints,
                            srh->sr_err_idx, DR_MAX_ERR_INT, (uint64_t)major);

                        ndi_hold_devi(dip);
                        srh->sr_failed_dip = dip;

                        handle = srh->sr_dr_handlep;
                        dr_op_err(CE_IGNORE, handle, ESBD_SUSPEND, "%s@%s",
                            d_name[0] ? d_name : dname, d_info);

                        return (DDI_FAILURE);
                }
        }

        return (DDI_SUCCESS);
}

static void
dr_resume_devices(dev_info_t *start, dr_sr_handle_t *srh)
{
        dr_handle_t     *handle;
        dev_info_t      *dip, *next, *last = NULL;
        major_t         major;
        char            *bn;
        int             circ;

        major = (major_t)-1;

        /* attach in reverse device tree order */
        while (last != start) {
                dip = start;
                next = ddi_get_next_sibling(dip);
                while (next != last && dip != srh->sr_failed_dip) {
                        dip = next;
                        next = ddi_get_next_sibling(dip);
                }
                if (dip == srh->sr_failed_dip) {
                        /* release hold acquired in dr_suspend_devices() */
                        srh->sr_failed_dip = NULL;
                        ndi_rele_devi(dip);
                } else if (dr_is_real_device(dip) &&
                    srh->sr_failed_dip == NULL) {

                        if ((bn = ddi_binding_name(dip)) != NULL) {
                                major = ddi_name_to_major(bn);
                        } else {
                                bn = "<null>";
                        }
                        if (!dr_bypass_device(bn) &&
                            !drmach_verify_sr(dip, 0)) {
                                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 (!dr_resolve_devname(dip, d_name, d_alias)) {
                                        if (d_alias[0] != 0) {
                                                prom_printf("\tresuming "
                                                    "%s@%s (aka %s)\n", d_name,
                                                    d_info, d_alias);
                                        } else {
                                                prom_printf("\tresuming "
                                                    "%s@%s\n", d_name, d_info);
                                        }
                                } else {
                                        prom_printf("\tresuming %s@%s\n", bn,
                                            d_info);
                                }

                                if (devi_attach(dip, DDI_RESUME) !=
                                    DDI_SUCCESS) {
                                        /*
                                         * Print a console warning,
                                         * set an e_code of ESBD_RESUME,
                                         * and save the driver major
                                         * number in the e_rsc.
                                         */
                                        prom_printf("\tFAILED to resume %s@%s",
                                            d_name[0] ? d_name : bn, d_info);

                                        srh->sr_err_idx =
                                            dr_add_int(srh->sr_err_ints,
                                            srh->sr_err_idx, DR_MAX_ERR_INT,
                                            (uint64_t)major);

                                        handle = srh->sr_dr_handlep;

                                        dr_op_err(CE_IGNORE, handle,
                                            ESBD_RESUME, "%s@%s",
                                            d_name[0] ? d_name : bn, d_info);
                                }
                        }
                }

                /* Hold parent busy while walking its children */
                ndi_devi_enter(dip, &circ);
                dr_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 complete in the kernel, they will process
 * the stop signal and stop.
 */
#define DR_VSTOPPED(t)                  \
        ((t)->t_state == TS_SLEEP &&    \
        (t)->t_wchan != NULL &&         \
        (t)->t_astflag &&               \
        ((t)->t_proc_flag & TP_CHKPT))

/* ARGSUSED */
static int
dr_stop_user_threads(dr_sr_handle_t *srh)
{
        int             count;
        int             bailout;
        dr_handle_t     *handle = srh->sr_dr_handlep;
        static fn_t     f = "dr_stop_user_threads";
        kthread_id_t    tp;

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

#define DR_UTSTOP_RETRY 4
#define DR_UTSTOP_WAIT  hz

        if (dr_skip_user_threads)
                return (DDI_SUCCESS);

        utstop_init();

        /* we need to try a few times to get past fork, etc. */
        srh->sr_err_idx = 0;
        for (count = 0; count < DR_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 (ISWAKEABLE(tp) || ISWAITING(tp)) {
                                        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 * DR_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) &&
                            !(dr_allow_blocked_threads &&
                            DR_VSTOPPED(tp))) {
                                bailout = 1;
                                if (count == DR_UTSTOP_RETRY - 1) {
                                        /*
                                         * save the pid for later reporting
                                         */
                                        srh->sr_err_idx =
                                            dr_add_int(srh->sr_err_ints,
                                            srh->sr_err_idx, DR_MAX_ERR_INT,
                                            (uint64_t)p->p_pid);

                                        cmn_err(CE_WARN, "%s: "
                                            "failed to stop thread: "
                                            "process=%s, pid=%d",
                                            f, p->p_user.u_psargs, p->p_pid);

                                        PR_QR("%s: failed to stop thread: "
                                            "process=%s, pid=%d, t_id=0x%p, "
                                            "t_state=0x%x, t_proc_flag=0x%x, "
                                            "t_schedflag=0x%x\n",
                                            f, p->p_user.u_psargs, p->p_pid,
                                            (void *)tp, tp->t_state,
                                            tp->t_proc_flag, tp->t_schedflag);
                                }

                        }
                        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) {
                handle->h_err = drerr_int(ESBD_UTHREAD, srh->sr_err_ints,
                    srh->sr_err_idx, 0);
                return (ESRCH);
        }

        return (DDI_SUCCESS);
}

static void
dr_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
dr_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);
}

void
dr_resume(dr_sr_handle_t *srh)
{
        if (srh->sr_suspend_state < DR_SRSTATE_FULL) {
                /*
                 * Update the signature block.
                 * If cpus are not paused, this can be done now.
                 * See comments below.
                 */
                CPU_SIGNATURE(OS_SIG, SIGST_RESUME_INPROGRESS, SIGSUBST_NULL,
                    CPU->cpu_id);
        }

        switch (srh->sr_suspend_state) {
        case DR_SRSTATE_FULL:

                ASSERT(MUTEX_HELD(&cpu_lock));

                /*
                 * Prevent false alarm in tod_validate() due to tod
                 * value change between suspend and resume
                 */
                mutex_enter(&tod_lock);
                tod_status_set(TOD_DR_RESUME_DONE);
                mutex_exit(&tod_lock);

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

                start_cpus();
                mutex_exit(&cpu_lock);

                /*
                 * Update the signature block.
                 * This must not be done while cpus are paused, since on
                 * Starcat the cpu signature update aquires an adaptive
                 * mutex in the iosram driver. Blocking with cpus paused
                 * can lead to deadlock.
                 */
                CPU_SIGNATURE(OS_SIG, SIGST_RESUME_INPROGRESS, SIGSUBST_NULL,
                    CPU->cpu_id);

                /*
                 * If we suspended hw watchdog at suspend,
                 * re-enable it now.
                 */
                if (srh->sr_flags & (SR_FLAG_WATCHDOG)) {
                        mutex_enter(&tod_lock);
                        tod_ops.tod_set_watchdog_timer(
                            watchdog_timeout_seconds);
                        mutex_exit(&tod_lock);
                }

                /*
                 * This should only be called if drmach_suspend_last()
                 * was called and state transitioned to DR_SRSTATE_FULL
                 * to prevent resume attempts on device instances that
                 * were not previously suspended.
                 */
                drmach_resume_first();

                /* FALLTHROUGH */

        case DR_SRSTATE_DRIVER:
                /*
                 * resume drivers
                 */
                srh->sr_err_idx = 0;

                /* no parent dip to hold busy */
                dr_resume_devices(ddi_root_node(), srh);

                if (srh->sr_err_idx && srh->sr_dr_handlep) {
                        (srh->sr_dr_handlep)->h_err = drerr_int(ESBD_RESUME,
                            srh->sr_err_ints, srh->sr_err_idx, 1);
                }

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

                /* FALLTHROUGH */

        case DR_SRSTATE_USER:
                /*
                 * finally, resume user threads
                 */
                if (!dr_skip_user_threads) {
                        prom_printf("DR: resuming user threads...\n");
                        dr_start_user_threads();
                }
                /* FALLTHROUGH */

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

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

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

int
dr_suspend(dr_sr_handle_t *srh)
{
        dr_handle_t     *handle;
        int             force;
        int             dev_errs_idx;
        uint64_t        dev_errs[DR_MAX_ERR_INT];
        int             rc = DDI_SUCCESS;

        handle = srh->sr_dr_handlep;

        force = dr_cmd_flags(handle) & SBD_FLAG_FORCE;

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

        prom_printf("\nDR: suspending user threads...\n");
        srh->sr_suspend_state = DR_SRSTATE_USER;
        if (((rc = dr_stop_user_threads(srh)) != DDI_SUCCESS) &&
            dr_check_user_stop_result) {
                dr_resume(srh);
                return (rc);
        }

        if (!force) {
                struct dr_ref drc = {0};

                prom_printf("\nDR: checking devices...\n");
                dev_errs_idx = 0;

                drc.arr = dev_errs;
                drc.idx = &dev_errs_idx;
                drc.len = DR_MAX_ERR_INT;

                /*
                 * Since the root node can never go away, it
                 * doesn't have to be held.
                 */
                ddi_walk_devs(ddi_root_node(), dr_check_unsafe_major, &drc);
                if (dev_errs_idx) {
                        handle->h_err = drerr_int(ESBD_UNSAFE, dev_errs,
                            dev_errs_idx, 1);
                        dr_resume(srh);
                        return (DDI_FAILURE);
                }
                PR_QR("done\n");
        } else {
                prom_printf("\nDR: dr_suspend invoked with force flag\n");
        }

#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
         */
        prom_printf("DR: suspending drivers...\n");
        srh->sr_suspend_state = DR_SRSTATE_DRIVER;
        srh->sr_err_idx = 0;
        /* No parent to hold busy */
        if ((rc = dr_suspend_devices(ddi_root_node(), srh)) != DDI_SUCCESS) {
                if (srh->sr_err_idx && srh->sr_dr_handlep) {
                        (srh->sr_dr_handlep)->h_err = drerr_int(ESBD_SUSPEND,
                            srh->sr_err_ints, srh->sr_err_idx, 1);
                }
                dr_resume(srh);
                return (rc);
        }

        drmach_suspend_last();

        /*
         * finally, grab all cpus
         */
        srh->sr_suspend_state = DR_SRSTATE_FULL;

        /*
         * if watchdog was activated, disable it
         */
        if (watchdog_activated) {
                mutex_enter(&tod_lock);
                tod_ops.tod_clear_watchdog_timer();
                mutex_exit(&tod_lock);
                srh->sr_flags |= SR_FLAG_WATCHDOG;
        } else {
                srh->sr_flags &= ~(SR_FLAG_WATCHDOG);
        }

        /*
         * Update the signature block.
         * This must be done before cpus are paused, since on Starcat the
         * cpu signature update aquires an adaptive mutex in the iosram driver.
         * Blocking with cpus paused can lead to deadlock.
         */
        CPU_SIGNATURE(OS_SIG, SIGST_QUIESCED, SIGSUBST_NULL, CPU->cpu_id);

        mutex_enter(&cpu_lock);
        pause_cpus(NULL, NULL);
        dr_stop_intr();

        return (rc);
}

int
dr_pt_test_suspend(dr_handle_t *hp)
{
        dr_sr_handle_t *srh;
        int             err;
        uint_t          psmerr;
        static fn_t     f = "dr_pt_test_suspend";

        PR_QR("%s...\n", f);

        srh = dr_get_sr_handle(hp);
        if ((err = dr_suspend(srh)) == DDI_SUCCESS) {
                dr_resume(srh);
                if ((hp->h_err) && ((psmerr = hp->h_err->e_code) != 0)) {
                        PR_QR("%s: error on dr_resume()", f);
                        switch (psmerr) {
                        case ESBD_RESUME:
                                PR_QR("Couldn't resume devices: %s\n",
                                    DR_GET_E_RSC(hp->h_err));
                                break;

                        case ESBD_KTHREAD:
                                PR_ALL("psmerr is ESBD_KTHREAD\n");
                                break;
                        default:
                                PR_ALL("Resume error unknown = %d\n", psmerr);
                                break;
                        }
                }
        } else {
                PR_ALL("%s: dr_suspend() failed, err = 0x%x\n", f, err);
                psmerr = hp->h_err ? hp->h_err->e_code : ESBD_NOERROR;
                switch (psmerr) {
                case ESBD_UNSAFE:
                        PR_ALL("Unsafe devices (major #): %s\n",
                            DR_GET_E_RSC(hp->h_err));
                        break;

                case ESBD_RTTHREAD:
                        PR_ALL("RT threads (PIDs): %s\n",
                            DR_GET_E_RSC(hp->h_err));
                        break;

                case ESBD_UTHREAD:
                        PR_ALL("User threads (PIDs): %s\n",
                            DR_GET_E_RSC(hp->h_err));
                        break;

                case ESBD_SUSPEND:
                        PR_ALL("Non-suspendable devices (major #): %s\n",
                            DR_GET_E_RSC(hp->h_err));
                        break;

                case ESBD_RESUME:
                        PR_ALL("Could not resume devices (major #): %s\n",
                            DR_GET_E_RSC(hp->h_err));
                        break;

                case ESBD_KTHREAD:
                        PR_ALL("psmerr is ESBD_KTHREAD\n");
                        break;

                case ESBD_NOERROR:
                        PR_ALL("sbd_error_t error code not set\n");
                        break;

                default:
                        PR_ALL("Unknown error psmerr = %d\n", psmerr);
                        break;
                }
        }
        dr_release_sr_handle(srh);

        return (0);
}

/*
 * Add a new integer value to the end of an array.  Don't allow duplicates to
 * appear in the array, and don't allow the array to overflow.  Return the new
 * total number of entries in the array.
 */
static int
dr_add_int(uint64_t *arr, int idx, int len, uint64_t val)
{
        int i;

        if (arr == NULL)
                return (0);

        if (idx >= len)
                return (idx);

        for (i = 0; i < idx; i++) {
                if (arr[i] == val)
                        return (idx);
        }

        arr[idx++] = val;

        return (idx);
}

/*
 * Construct an sbd_error_t featuring a string representation of an array of
 * integers as its e_rsc.
 */
static sbd_error_t *
drerr_int(int e_code, uint64_t *arr, int idx, int majors)
{
        int             i, n, buf_len, buf_idx, buf_avail;
        char            *dname;
        char            *buf;
        sbd_error_t     *new_sbd_err;
        static char     s_ellipsis[] = "...";

        if (arr == NULL || idx <= 0)
                return (NULL);

        /* MAXPATHLEN is the size of the e_rsc field in sbd_error_t. */
        buf = (char *)kmem_zalloc(MAXPATHLEN, KM_SLEEP);

        /*
         * This is the total working area of the buffer.  It must be computed
         * as the size of 'buf', minus reserved space for the null terminator
         * and the ellipsis string.
         */
        buf_len = MAXPATHLEN - (strlen(s_ellipsis) + 1);

        /* Construct a string representation of the array values */
        for (buf_idx = 0, i = 0; i < idx; i++) {
                buf_avail = buf_len - buf_idx;
                if (majors) {
                        dname = ddi_major_to_name(arr[i]);
                        if (dname) {
                                n = snprintf(&buf[buf_idx], buf_avail, "%s, ",
                                    dname);
                        } else {
                                n = snprintf(&buf[buf_idx], buf_avail,
                                    "major %lu, ", arr[i]);
                        }
                } else {
                        n = snprintf(&buf[buf_idx], buf_avail, "%lu, ", arr[i]);
                }

                /* An ellipsis gets appended when no more values fit */
                if (n >= buf_avail) {
                        (void) strcpy(&buf[buf_idx], s_ellipsis);
                        break;
                }

                buf_idx += n;
        }

        /* If all the contents fit, remove the trailing comma */
        if (n < buf_avail) {
                buf[--buf_idx] = '\0';
                buf[--buf_idx] = '\0';
        }

        /* Return an sbd_error_t with the buffer and e_code */
        new_sbd_err = drerr_new(1, e_code, buf);
        kmem_free(buf, MAXPATHLEN);
        return (new_sbd_err);
}