xnu-4570.1.46.tar.gz

[apple/xnu.git] / bsd / dev / dtrace / profile_prvd.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        "@(#)profile.c  1.7     07/01/10 SMI" */

#ifdef KERNEL
#ifndef _KERNEL
#define _KERNEL /* Solaris vs. Darwin */
#endif
#endif

#include <kern/cpu_data.h>
#include <kern/thread.h>
#include <kern/assert.h>
#include <mach/thread_status.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <miscfs/devfs/devfs.h>

#include <sys/dtrace.h>
#include <sys/dtrace_impl.h>

#include <sys/dtrace_glue.h>

#include <machine/pal_routines.h>

#if defined(__x86_64__)
extern x86_saved_state_t *find_kern_regs(thread_t);
#elif defined (__arm__) || defined(__arm64__)
extern struct arm_saved_state *find_kern_regs(thread_t);
#else
#error Unknown architecture
#endif

#undef ASSERT
#define ASSERT(x) do {} while(0)

extern void profile_init(void);

static dev_info_t *profile_devi;
static dtrace_provider_id_t profile_id;

/*
 * Regardless of platform, the stack frames look like this in the case of the
 * profile provider:
 *
 *      profile_fire
 *      cyclic_expire
 *      cyclic_fire
 *      [ cbe ]
 *      [ interrupt code ]
 *
 * On x86, there are five frames from the generic interrupt code; further, the
 * interrupted instruction appears as its own stack frame, giving us a total of
 * 10.
 *
 * On SPARC, the picture is further complicated because the compiler
 * optimizes away tail-calls -- so the following frames are optimized away:
 *
 *      profile_fire
 *      cyclic_expire
 *
 * This gives three frames.  However, on DEBUG kernels, the cyclic_expire
 * frame cannot be tail-call eliminated, yielding four frames in this case.
 *
 * All of the above constraints lead to the mess below.  Yes, the profile
 * provider should ideally figure this out on-the-fly by hitting one of its own
 * probes and then walking its own stack trace.  This is complicated, however,
 * and the static definition doesn't seem to be overly brittle.  Still, we
 * allow for a manual override in case we get it completely wrong.
 */

#if defined(__x86_64__)
#define PROF_ARTIFICIAL_FRAMES  9
#elif defined(__arm__) || defined(__arm64__)
#define PROF_ARTIFICIAL_FRAMES 8
#else
#error Unknown architecture
#endif

#define PROF_NAMELEN            15

#define PROF_PROFILE            0
#define PROF_TICK               1
#define PROF_PREFIX_PROFILE     "profile-"
#define PROF_PREFIX_TICK        "tick-"

typedef struct profile_probe {
        char            prof_name[PROF_NAMELEN];
        dtrace_id_t     prof_id;
        int             prof_kind;
        hrtime_t        prof_interval;
        cyclic_id_t     prof_cyclic;
} profile_probe_t;

typedef struct profile_probe_percpu {
        hrtime_t        profc_expected;
        hrtime_t        profc_interval;
        profile_probe_t *profc_probe;
} profile_probe_percpu_t;

hrtime_t        profile_interval_min = NANOSEC / 5000;          /* 5000 hz */
int             profile_aframes = 0;                            /* override */

static int profile_rates[] = {
    97, 199, 499, 997, 1999,
    4001, 4999, 0, 0, 0,
    0, 0, 0, 0, 0,
    0, 0, 0, 0, 0
};

static int profile_ticks[] = {
    1, 10, 100, 500, 1000,
    5000, 0, 0, 0, 0,
    0, 0, 0, 0, 0
};

/*
 * profile_max defines the upper bound on the number of profile probes that
 * can exist (this is to prevent malicious or clumsy users from exhausing
 * system resources by creating a slew of profile probes). At mod load time,
 * this gets its value from PROFILE_MAX_DEFAULT or profile-max-probes if it's
 * present in the profile.conf file.
 */
#define PROFILE_MAX_DEFAULT     1000    /* default max. number of probes */
static uint32_t profile_max;            /* maximum number of profile probes */
static uint32_t profile_total;  /* current number of profile probes */

static void
profile_fire(void *arg)
{
        profile_probe_percpu_t *pcpu = arg;
        profile_probe_t *prof = pcpu->profc_probe;
        hrtime_t late;

        late = dtrace_gethrtime() - pcpu->profc_expected;
        pcpu->profc_expected += pcpu->profc_interval;

#if defined(__x86_64__)
        x86_saved_state_t *kern_regs = find_kern_regs(current_thread());

        if (NULL != kern_regs) {
                /* Kernel was interrupted. */
                dtrace_probe(prof->prof_id, saved_state64(kern_regs)->isf.rip,  0x0, late, 0, 0);

        } else {
                pal_register_cache_state(current_thread(), VALID);
                /* Possibly a user interrupt */
                x86_saved_state_t   *tagged_regs = (x86_saved_state_t *)find_user_regs(current_thread());

                if (NULL == tagged_regs) {
                        /* Too bad, so sad, no useful interrupt state. */
                        dtrace_probe(prof->prof_id, 0xcafebabe,
                        0x0, late, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                } else if (is_saved_state64(tagged_regs)) {
                        x86_saved_state64_t *regs = saved_state64(tagged_regs);

                        dtrace_probe(prof->prof_id, 0x0, regs->isf.rip, late, 0, 0);
                } else {
                        x86_saved_state32_t *regs = saved_state32(tagged_regs);

                        dtrace_probe(prof->prof_id, 0x0, regs->eip, late, 0, 0);
                }
        }
#elif defined(__arm__)
        {
                arm_saved_state_t *arm_kern_regs = (arm_saved_state_t *) find_kern_regs(current_thread());

                // We should only come in here from interrupt context, so we should always have valid kernel regs
                assert(NULL != arm_kern_regs);

                if (arm_kern_regs->cpsr & 0xF) {
                        /* Kernel was interrupted. */
                        dtrace_probe(prof->prof_id, arm_kern_regs->pc,  0x0, late, 0, 0);
                } else {
                        /* Possibly a user interrupt */
                        arm_saved_state_t   *arm_user_regs = (arm_saved_state_t *)find_user_regs(current_thread());

                        if (NULL == arm_user_regs) {
                                /* Too bad, so sad, no useful interrupt state. */
                                dtrace_probe(prof->prof_id, 0xcafebabe, 0x0, late, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                        } else {
                                dtrace_probe(prof->prof_id, 0x0, arm_user_regs->pc, late, 0, 0);
                        }
                }
        }
#elif defined(__arm64__)
        {
                arm_saved_state_t *arm_kern_regs = (arm_saved_state_t *) find_kern_regs(current_thread());

                // We should only come in here from interrupt context, so we should always have valid kernel regs
                assert(NULL != arm_kern_regs);

                if (saved_state64(arm_kern_regs)->cpsr & 0xF) {
                        /* Kernel was interrupted. */
                        dtrace_probe(prof->prof_id, saved_state64(arm_kern_regs)->pc,  0x0, late, 0, 0);
                } else {
                        /* Possibly a user interrupt */
                        arm_saved_state_t   *arm_user_regs = (arm_saved_state_t *)find_user_regs(current_thread());

                        if (NULL == arm_user_regs) {
                                /* Too bad, so sad, no useful interrupt state. */
                                dtrace_probe(prof->prof_id, 0xcafebabe, 0x0, late, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                        } else {
                                dtrace_probe(prof->prof_id, 0x0, get_saved_state_pc(arm_user_regs), late, 0, 0);
                        }
                }
        }
#else
#error Unknown architecture
#endif
}

static void
profile_tick(void *arg)
{
        profile_probe_t *prof = arg;

#if defined(__x86_64__)
        x86_saved_state_t *kern_regs = find_kern_regs(current_thread());

        if (NULL != kern_regs) {
                /* Kernel was interrupted. */
                dtrace_probe(prof->prof_id, saved_state64(kern_regs)->isf.rip,  0x0, 0, 0, 0);
        } else {
                pal_register_cache_state(current_thread(), VALID);
                /* Possibly a user interrupt */
                x86_saved_state_t   *tagged_regs = (x86_saved_state_t *)find_user_regs(current_thread());

                if (NULL == tagged_regs) {
                        /* Too bad, so sad, no useful interrupt state. */
                        dtrace_probe(prof->prof_id, 0xcafebabe,
                        0x0, 0, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                } else if (is_saved_state64(tagged_regs)) {
                        x86_saved_state64_t *regs = saved_state64(tagged_regs);

                        dtrace_probe(prof->prof_id, 0x0, regs->isf.rip, 0, 0, 0);
                } else {
                        x86_saved_state32_t *regs = saved_state32(tagged_regs);

                        dtrace_probe(prof->prof_id, 0x0, regs->eip, 0, 0, 0);
                }
        }
#elif defined(__arm__)
        {
                arm_saved_state_t *arm_kern_regs = (arm_saved_state_t *) find_kern_regs(current_thread());

                if (NULL != arm_kern_regs) {
                        /* Kernel was interrupted. */
                        dtrace_probe(prof->prof_id, arm_kern_regs->pc,  0x0, 0, 0, 0);
                } else {
                        /* Possibly a user interrupt */
                        arm_saved_state_t   *arm_user_regs = (arm_saved_state_t *)find_user_regs(current_thread());

                        if (NULL == arm_user_regs) {
                                /* Too bad, so sad, no useful interrupt state. */
                                dtrace_probe(prof->prof_id, 0xcafebabe, 0x0, 0, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                        } else {
                                dtrace_probe(prof->prof_id, 0x0, arm_user_regs->pc, 0, 0, 0);
                        }
                }
        }
#elif defined(__arm64__)
        {
                arm_saved_state_t *arm_kern_regs = (arm_saved_state_t *) find_kern_regs(current_thread());

                if (NULL != arm_kern_regs) {
                        /* Kernel was interrupted. */
                        dtrace_probe(prof->prof_id, saved_state64(arm_kern_regs)->pc,  0x0, 0, 0, 0);
                } else {
                        /* Possibly a user interrupt */
                        arm_saved_state_t   *arm_user_regs = (arm_saved_state_t *)find_user_regs(current_thread());

                        if (NULL == arm_user_regs) {
                                /* Too bad, so sad, no useful interrupt state. */
                                dtrace_probe(prof->prof_id, 0xcafebabe, 0x0, 0, 0, 0); /* XXX_BOGUS also see profile_usermode() below. */
                        } else {
                                dtrace_probe(prof->prof_id, 0x0, get_saved_state_pc(arm_user_regs), 0, 0, 0);
                        }
                }
        }

#else
#error Unknown architecture
#endif
}

static void
profile_create(hrtime_t interval, const char *name, int kind)
{
        profile_probe_t *prof;

        if (interval < profile_interval_min)
                return;

        if (dtrace_probe_lookup(profile_id, NULL, NULL, name) != 0)
                return;

        atomic_add_32(&profile_total, 1);
        if (profile_total > profile_max) {
                atomic_add_32(&profile_total, -1);
                return;
        }

        if (PROF_TICK == kind)
                prof = kmem_zalloc(sizeof (profile_probe_t), KM_SLEEP);
        else
                prof = kmem_zalloc(sizeof (profile_probe_t) + NCPU*sizeof(profile_probe_percpu_t), KM_SLEEP);

        (void) strlcpy(prof->prof_name, name, sizeof(prof->prof_name));
        prof->prof_interval = interval;
        prof->prof_cyclic = CYCLIC_NONE;
        prof->prof_kind = kind;
        prof->prof_id = dtrace_probe_create(profile_id,
            NULL, NULL, name,
            profile_aframes ? profile_aframes : PROF_ARTIFICIAL_FRAMES, prof);
}

/*ARGSUSED*/
static void
profile_provide(void *arg, const dtrace_probedesc_t *desc)
{
#pragma unused(arg) /* __APPLE__ */
        int i, j, rate, kind;
        hrtime_t val = 0, mult = 1, len;
        const char *name, *suffix = NULL;

        const struct {
                const char *prefix;
                int kind;
        } types[] = {
                { PROF_PREFIX_PROFILE, PROF_PROFILE },
                { PROF_PREFIX_TICK, PROF_TICK },
                { NULL, 0 }
        };

        const struct {
                const char *name;
                hrtime_t mult;
        } suffixes[] = {
                { "ns",         NANOSEC / NANOSEC },
                { "nsec",       NANOSEC / NANOSEC },
                { "us",         NANOSEC / MICROSEC },
                { "usec",       NANOSEC / MICROSEC },
                { "ms",         NANOSEC / MILLISEC },
                { "msec",       NANOSEC / MILLISEC },
                { "s",          NANOSEC / SEC },
                { "sec",        NANOSEC / SEC },
                { "m",          NANOSEC * (hrtime_t)60 },
                { "min",        NANOSEC * (hrtime_t)60 },
                { "h",          NANOSEC * (hrtime_t)(60 * 60) },
                { "hour",       NANOSEC * (hrtime_t)(60 * 60) },
                { "d",          NANOSEC * (hrtime_t)(24 * 60 * 60) },
                { "day",        NANOSEC * (hrtime_t)(24 * 60 * 60) },
                { "hz",         0 },
                { NULL, 0 }
        };              

        if (desc == NULL) {
                char n[PROF_NAMELEN];

                /*
                 * If no description was provided, provide all of our probes.
                 */
                for (i = 0; i < (int)(sizeof (profile_rates) / sizeof (int)); i++) {
                        if ((rate = profile_rates[i]) == 0)
                                continue;

                        (void) snprintf(n, PROF_NAMELEN, "%s%d",
                            PROF_PREFIX_PROFILE, rate);
                        profile_create(NANOSEC / rate, n, PROF_PROFILE);
                }

                for (i = 0; i < (int)(sizeof (profile_ticks) / sizeof (int)); i++) {
                        if ((rate = profile_ticks[i]) == 0)
                                continue;

                        (void) snprintf(n, PROF_NAMELEN, "%s%d",
                            PROF_PREFIX_TICK, rate);
                        profile_create(NANOSEC / rate, n, PROF_TICK);
                }

                return;
        }

        name = desc->dtpd_name;

        for (i = 0; types[i].prefix != NULL; i++) {
                len = strlen(types[i].prefix);

                if (strncmp(name, types[i].prefix, len) != 0)
                        continue;
                break;
        }

        if (types[i].prefix == NULL)
                return;

        kind = types[i].kind;
        j = strlen(name) - len;

        /*
         * We need to start before any time suffix.
         */
        for (j = strlen(name); j >= len; j--) {
                if (name[j] >= '0' && name[j] <= '9')
                        break;
                suffix = &name[j];
        }

        ASSERT(suffix != NULL);

        /*
         * Now determine the numerical value present in the probe name.
         */
        for (; j >= len; j--) {
                if (name[j] < '0' || name[j] > '9')
                        return;

                val += (name[j] - '0') * mult;
                mult *= (hrtime_t)10;
        }

        if (val == 0)
                return;

        /*
         * Look-up the suffix to determine the multiplier.
         */
        for (i = 0, mult = 0; suffixes[i].name != NULL; i++) {
                /* APPLE NOTE: Darwin employs size bounded string operations */
                if (strncasecmp(suffixes[i].name, suffix, strlen(suffixes[i].name) + 1) == 0) {
                        mult = suffixes[i].mult;
                        break;
                }
        }

        if (suffixes[i].name == NULL && *suffix != '\0')
                return;

        if (mult == 0) {
                /*
                 * The default is frequency-per-second.
                 */
                val = NANOSEC / val;
        } else {
                val *= mult;
        }

        profile_create(val, name, kind);
}

/*ARGSUSED*/
static void
profile_destroy(void *arg, dtrace_id_t id, void *parg)
{
#pragma unused(arg,id) /* __APPLE__ */
        profile_probe_t *prof = parg;

        ASSERT(prof->prof_cyclic == CYCLIC_NONE);

        if (prof->prof_kind == PROF_TICK)
                kmem_free(prof, sizeof (profile_probe_t));
        else
                kmem_free(prof, sizeof (profile_probe_t) + NCPU*sizeof(profile_probe_percpu_t));

        ASSERT(profile_total >= 1);
        atomic_add_32(&profile_total, -1);
}

/*ARGSUSED*/
static void
profile_online(void *arg, dtrace_cpu_t *cpu, cyc_handler_t *hdlr, cyc_time_t *when)
{
#pragma unused(cpu) /* __APPLE__ */
        profile_probe_t *prof = arg;
        profile_probe_percpu_t *pcpu;

        pcpu = ((profile_probe_percpu_t *)(&(prof[1]))) + cpu_number();
        pcpu->profc_probe = prof;

        hdlr->cyh_func = profile_fire;
        hdlr->cyh_arg = pcpu;
        hdlr->cyh_level = CY_HIGH_LEVEL;

        when->cyt_interval = prof->prof_interval;
        when->cyt_when = dtrace_gethrtime() + when->cyt_interval;

        pcpu->profc_expected = when->cyt_when;
        pcpu->profc_interval = when->cyt_interval;
}

/*ARGSUSED*/
static void
profile_offline(void *arg, dtrace_cpu_t *cpu, void *oarg)
{
        profile_probe_percpu_t *pcpu = oarg;

        ASSERT(pcpu->profc_probe == arg);
#pragma unused(pcpu,arg,cpu) /* __APPLE__ */
}

/*ARGSUSED*/
static int
profile_enable(void *arg, dtrace_id_t id, void *parg)
{
#pragma unused(arg,id) /* __APPLE__ */
        profile_probe_t *prof = parg;
        cyc_omni_handler_t omni;
        cyc_handler_t hdlr;
        cyc_time_t when;

        ASSERT(prof->prof_interval != 0);
        ASSERT(MUTEX_HELD(&cpu_lock));

        if (prof->prof_kind == PROF_TICK) {
                hdlr.cyh_func = profile_tick;
                hdlr.cyh_arg = prof;
                hdlr.cyh_level = CY_HIGH_LEVEL;

                when.cyt_interval = prof->prof_interval;
#if !defined(__APPLE__)
                when.cyt_when = dtrace_gethrtime() + when.cyt_interval;
#else
                when.cyt_when = 0;
#endif /* __APPLE__ */
        } else {
                ASSERT(prof->prof_kind == PROF_PROFILE);
                omni.cyo_online = profile_online;
                omni.cyo_offline = profile_offline;
                omni.cyo_arg = prof;
        }

        if (prof->prof_kind == PROF_TICK) {
                prof->prof_cyclic = cyclic_timer_add(&hdlr, &when);
        } else {
                prof->prof_cyclic = (cyclic_id_t)cyclic_add_omni(&omni); /* cast puns cyclic_id_list_t with cyclic_id_t */
        }

        return(0);
}

/*ARGSUSED*/
static void
profile_disable(void *arg, dtrace_id_t id, void *parg)
{
        profile_probe_t *prof = parg;

        ASSERT(prof->prof_cyclic != CYCLIC_NONE);
        ASSERT(MUTEX_HELD(&cpu_lock));

#pragma unused(arg,id)
        if (prof->prof_kind == PROF_TICK) {
                cyclic_timer_remove(prof->prof_cyclic);
        } else {
                cyclic_remove_omni((cyclic_id_list_t)prof->prof_cyclic); /* cast puns cyclic_id_list_t with cyclic_id_t */
        }
        prof->prof_cyclic = CYCLIC_NONE;
}

static uint64_t
profile_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes)
{
#pragma unused(arg, id, parg, argno, aframes)
        /*
         * All the required arguments for the profile probe are passed directly
         * to dtrace_probe, and we do not go through dtrace_getarg which doesn't
         * know how to hop to the kernel stack from the interrupt stack like
         * dtrace_getpcstack
         */
        return 0;
}

static void
profile_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
{
#pragma unused(arg, id)
        profile_probe_t *prof = parg;
        const char *argdesc = NULL;
        switch (desc->dtargd_ndx) {
                case 0:
                        argdesc = "void*";
                        break;
                case 1:
                        argdesc = "user_addr_t";
                        break;
                case 2:
                        if (prof->prof_kind == PROF_PROFILE) {
                                argdesc = "hrtime_t";
                        }
                        break;
        }
        if (argdesc) {
                strlcpy(desc->dtargd_native, argdesc, DTRACE_ARGTYPELEN);
        }
        else {
                desc->dtargd_ndx = DTRACE_ARGNONE;
        }
}

/*
 * APPLE NOTE:  profile_usermode call not supported.
 */
static int
profile_usermode(void *arg, dtrace_id_t id, void *parg)
{
#pragma unused(arg,id,parg)
        return 1; /* XXX_BOGUS */
}

static dtrace_pattr_t profile_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_UNSTABLE, DTRACE_STABILITY_UNSTABLE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
};

static dtrace_pops_t profile_pops = {
        profile_provide,
        NULL,
        profile_enable,
        profile_disable,
        NULL,
        NULL,
        profile_getargdesc,
        profile_getarg,
        profile_usermode,
        profile_destroy
};

static int
profile_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
        switch (cmd) {
        case DDI_ATTACH:
                break;
        case DDI_RESUME:
                return (DDI_SUCCESS);
        default:
                return (DDI_FAILURE);
        }

        if (ddi_create_minor_node(devi, "profile", S_IFCHR, 0,
            DDI_PSEUDO, 0) == DDI_FAILURE ||
            dtrace_register("profile", &profile_attr,
            DTRACE_PRIV_KERNEL | DTRACE_PRIV_USER, NULL,
            &profile_pops, NULL, &profile_id) != 0) {
                ddi_remove_minor_node(devi, NULL);
                return (DDI_FAILURE);
        }

        profile_max = PROFILE_MAX_DEFAULT;

        ddi_report_dev(devi);
        profile_devi = devi;
        return (DDI_SUCCESS);
}

/*
 * APPLE NOTE:  profile_detach not implemented
 */
#if !defined(__APPLE__)
static int
profile_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
        switch (cmd) {
        case DDI_DETACH:
                break;
        case DDI_SUSPEND:
                return (DDI_SUCCESS);
        default:
                return (DDI_FAILURE);
        }

        if (dtrace_unregister(profile_id) != 0)
                return (DDI_FAILURE);

        ddi_remove_minor_node(devi, NULL);
        return (DDI_SUCCESS);
}
#endif /* __APPLE__ */

d_open_t _profile_open;

int _profile_open(dev_t dev, int flags, int devtype, struct proc *p)
{
#pragma unused(dev,flags,devtype,p)
        return 0;
}

#define PROFILE_MAJOR  -24 /* let the kernel pick the device number */

/*
 * A struct describing which functions will get invoked for certain
 * actions.
 */
static struct cdevsw profile_cdevsw =
{
        _profile_open,          /* open */
        eno_opcl,                       /* close */
        eno_rdwrt,                      /* read */
        eno_rdwrt,                      /* write */
        eno_ioctl,                      /* ioctl */
        (stop_fcn_t *)nulldev, /* stop */
        (reset_fcn_t *)nulldev, /* reset */
        NULL,                           /* tty's */
        eno_select,                     /* select */
        eno_mmap,                       /* mmap */
        eno_strat,                      /* strategy */
        eno_getc,                       /* getc */
        eno_putc,                       /* putc */
        0                                       /* type */
};

static int gProfileInited = 0;

void profile_init( void )
{
        if (0 == gProfileInited)
        {
                int majdevno = cdevsw_add(PROFILE_MAJOR, &profile_cdevsw);
                
                if (majdevno < 0) {
                        printf("profile_init: failed to allocate a major number!\n");
                        gProfileInited = 0;
                        return;
                }

                profile_attach( (dev_info_t     *)(uintptr_t)majdevno, DDI_ATTACH );

                gProfileInited = 1;
        } else
                panic("profile_init: called twice!\n");
}
#undef PROFILE_MAJOR