/*      $NetBSD: subr_prof.c,v 1.52 2026/01/04 03:20:46 riastradh Exp $ */

/*-
 * Copyright (c) 1982, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)subr_prof.c 8.4 (Berkeley) 2/14/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_prof.c,v 1.52 2026/01/04 03:20:46 riastradh Exp $");

#ifdef _KERNEL_OPT
#include "opt_gprof.h"
#include "opt_multiprocessor.h"
#endif

#include <sys/param.h>
#include <sys/types.h>

#include <sys/cpu.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/sdt.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#ifdef GPROF
#include <sys/gmon.h>
#include <sys/malloc.h>
#include <sys/xcall.h>

MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");

static int sysctl_kern_profiling(SYSCTLFN_ARGS);
#ifdef MULTIPROCESSOR
void _gmonparam_merge(struct gmonparam *, struct gmonparam *);
#endif

/*
 * Froms is actually a bunch of unsigned shorts indexing tos
 */
struct gmonparam _gmonparam = { .state = GMON_PROF_OFF };

/* Actual start of the kernel text segment. */
extern char kernel_text[];

extern char etext[];


void
kmstartup(void)
{
        char *cp;
        struct gmonparam *p = &_gmonparam;
        unsigned long size;
        /*
         * Round lowpc and highpc to multiples of the density we're using
         * so the rest of the scaling (here and in gprof) stays in ints.
         */
        p->lowpc = rounddown(((u_long)kernel_text),
                HISTFRACTION * sizeof(HISTCOUNTER));
        p->highpc = roundup((u_long)etext,
                HISTFRACTION * sizeof(HISTCOUNTER));
        p->textsize = p->highpc - p->lowpc;
        printf("Profiling kernel, textsize=%ld [%lx..%lx]\n",
               p->textsize, p->lowpc, p->highpc);
        p->kcountsize = p->textsize / HISTFRACTION;
        p->hashfraction = HASHFRACTION;
        p->fromssize = p->textsize / HASHFRACTION;
        p->tolimit = p->textsize * ARCDENSITY / 100;
        if (p->tolimit < MINARCS)
                p->tolimit = MINARCS;
        else if (p->tolimit > MAXARCS)
                p->tolimit = MAXARCS;
        p->tossize = p->tolimit * sizeof(struct tostruct);

        size = p->kcountsize + p->fromssize + p->tossize;
#ifdef MULTIPROCESSOR
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci;
        for (CPU_INFO_FOREACH(cii, ci)) {
                p = malloc(sizeof(struct gmonparam) + size, M_GPROF,
                    M_NOWAIT | M_ZERO);
                if (p == NULL) {
                        printf("No memory for profiling on %s\n",
                            cpu_name(ci));
                        /* cannot profile on this cpu */
                        continue;
                }
                memcpy(p, &_gmonparam, sizeof(_gmonparam));
                ci->ci_gmon = p;

                /*
                 * To allow profiling to be controlled only by the global
                 * _gmonparam.state, set the default value for each CPU to
                 * GMON_PROF_ON. If _gmonparam.state is not ON, mcount will
                 * not be executed.
                 * This is For compatibility of the kgmon(8) kmem interface.
                 */
                p->state = GMON_PROF_ON;

                cp = (char *)(p + 1);
                p->tos = (struct tostruct *)cp;
                p->kcount = (u_short *)(cp + p->tossize);
                p->froms = (u_short *)(cp + p->tossize + p->kcountsize);
        }

        sysctl_createv(NULL, 0, NULL, NULL,
            0, CTLTYPE_NODE, "percpu",
            SYSCTL_DESCR("per cpu profiling information"),
            NULL, 0, NULL, 0,
            CTL_KERN, KERN_PROF, GPROF_PERCPU, CTL_EOL);

        for (CPU_INFO_FOREACH(cii, ci)) {
                if (ci->ci_gmon == NULL)
                        continue;

                sysctl_createv(NULL, 0, NULL, NULL,
                    0, CTLTYPE_NODE, cpu_name(ci),
                    NULL,
                    NULL, 0, NULL, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci), CTL_EOL);

                sysctl_createv(NULL, 0, NULL, NULL,
                    CTLFLAG_READWRITE, CTLTYPE_INT, "state",
                    SYSCTL_DESCR("Profiling state"),
                    sysctl_kern_profiling, 0, (void *)ci, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci),
                    GPROF_STATE, CTL_EOL);
                sysctl_createv(NULL, 0, NULL, NULL,
                    CTLFLAG_READWRITE, CTLTYPE_STRUCT, "count",
                    SYSCTL_DESCR("Array of statistical program counters"),
                    sysctl_kern_profiling, 0, (void *)ci, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci),
                    GPROF_COUNT, CTL_EOL);
                sysctl_createv(NULL, 0, NULL, NULL,
                    CTLFLAG_READWRITE, CTLTYPE_STRUCT, "froms",
                    SYSCTL_DESCR("Array indexed by program counter of "
                    "call-from points"),
                    sysctl_kern_profiling, 0, (void *)ci, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci),
                    GPROF_FROMS, CTL_EOL);
                sysctl_createv(NULL, 0, NULL, NULL,
                    CTLFLAG_READWRITE, CTLTYPE_STRUCT, "tos",
                    SYSCTL_DESCR("Array of structures describing "
                    "destination of calls and their counts"),
                    sysctl_kern_profiling, 0, (void *)ci, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci),
                    GPROF_TOS, CTL_EOL);
                sysctl_createv(NULL, 0, NULL, NULL,
                    CTLFLAG_READWRITE, CTLTYPE_STRUCT, "gmonparam",
                    SYSCTL_DESCR("Structure giving the sizes of the above "
                    "arrays"),
                    sysctl_kern_profiling, 0, (void *)ci, 0,
                    CTL_KERN, KERN_PROF, GPROF_PERCPU, cpu_index(ci),
                    GPROF_GMONPARAM, CTL_EOL);
        }

        /*
         * For minimal compatibility of the kgmon(8) kmem interface,
         * the _gmonparam and cpu0:ci_gmon share buffers.
         */
        p = curcpu()->ci_gmon;
        if (p != NULL) {
                _gmonparam.tos = p->tos;
                _gmonparam.kcount = p->kcount;
                _gmonparam.froms = p->froms;
        }
#else /* MULTIPROCESSOR */
        cp = malloc(size, M_GPROF, M_NOWAIT | M_ZERO);
        if (cp == 0) {
                printf("No memory for profiling.\n");
                return;
        }
        p->tos = (struct tostruct *)cp;
        cp += p->tossize;
        p->kcount = (u_short *)cp;
        cp += p->kcountsize;
        p->froms = (u_short *)cp;
#endif /* MULTIPROCESSOR */
}

#ifdef MULTIPROCESSOR
static void
prof_set_state_xc(void *arg1, void *arg2 __unused)
{
        int state = PTRTOUINT64(arg1);
        struct gmonparam *gp = curcpu()->ci_gmon;

        if (gp != NULL)
                gp->state = state;
}
#endif /* MULTIPROCESSOR */

/*
 * Return kernel profiling information.
 */
/*
 * sysctl helper routine for kern.profiling subtree.  enables/disables
 * kernel profiling and gives out copies of the profiling data.
 */
static int
sysctl_kern_profiling(SYSCTLFN_ARGS)
{
        struct sysctlnode node = *rnode;
        struct gmonparam *gp;
        int error;
#ifdef MULTIPROCESSOR
        CPU_INFO_ITERATOR cii;
        struct cpu_info *ci, *target_ci;
        uint64_t where;
        int state;
        bool prof_on, do_merge;

        target_ci = (struct cpu_info *)rnode->sysctl_data;
        do_merge = (oldp != NULL) && (target_ci == NULL) &&
            ((node.sysctl_num == GPROF_COUNT) ||
            (node.sysctl_num == GPROF_FROMS) ||
            (node.sysctl_num == GPROF_TOS));

        if (do_merge) {
                /* kern.profiling.{count,froms,tos} */
                unsigned long size;
                char *cp;

                /* allocate temporary gmonparam, and merge results of all CPU */
                size = _gmonparam.kcountsize + _gmonparam.fromssize +
                    _gmonparam.tossize;
                gp = malloc(sizeof(struct gmonparam) + size, M_GPROF,
                    M_NOWAIT | M_ZERO);
                if (gp == NULL)
                        return SET_ERROR(ENOMEM);
                memcpy(gp, &_gmonparam, sizeof(_gmonparam));
                cp = (char *)(gp + 1);
                gp->tos = (struct tostruct *)cp;
                gp->kcount = (u_short *)(cp + gp->tossize);
                gp->froms = (u_short *)(cp + gp->tossize + gp->kcountsize);

                for (CPU_INFO_FOREACH(cii, ci)) {
                        if (ci->ci_gmon == NULL)
                                continue;
                        _gmonparam_merge(gp, ci->ci_gmon);
                }
        } else if (target_ci != NULL) {
                /* kern.profiling.percpu.* */
                gp = target_ci->ci_gmon;
        } else {
                /* kern.profiling.{state,gmonparam} */
                gp = &_gmonparam;
        }
#else /* MULTIPROCESSOR */
        gp = &_gmonparam;
#endif

        switch (node.sysctl_num) {
        case GPROF_STATE:
#ifdef MULTIPROCESSOR
                /*
                 * if _gmonparam.state is OFF, the state of each CPU is
                 * considered to be OFF, even if it is actually ON.
                 */
                if (_gmonparam.state == GMON_PROF_OFF ||
                    gp->state == GMON_PROF_OFF)
                        state = GMON_PROF_OFF;
                else
                        state = GMON_PROF_ON;
                node.sysctl_data = &state;
#else
                node.sysctl_data = &gp->state;
#endif
                break;
        case GPROF_COUNT:
                node.sysctl_data = gp->kcount;
                node.sysctl_size = gp->kcountsize;
                break;
        case GPROF_FROMS:
                node.sysctl_data = gp->froms;
                node.sysctl_size = gp->fromssize;
                break;
        case GPROF_TOS:
                node.sysctl_data = gp->tos;
                node.sysctl_size = gp->tossize;
                break;
        case GPROF_GMONPARAM:
                node.sysctl_data = gp;
                node.sysctl_size = sizeof(*gp);
                break;
        default:
                return SET_ERROR(EOPNOTSUPP);
        }

        error = sysctl_lookup(SYSCTLFN_CALL(&node));
        if (error || newp == NULL)
                goto done;

#ifdef MULTIPROCESSOR
        switch (node.sysctl_num) {
        case GPROF_STATE:
                if (target_ci != NULL) {
                        where = xc_unicast(0, prof_set_state_xc,
                            UINT64TOPTR(state), NULL, target_ci);
                        xc_wait(where);

                        /* if even one CPU being profiled, enable perfclock. */
                        prof_on = false;
                        for (CPU_INFO_FOREACH(cii, ci)) {
                                if (ci->ci_gmon == NULL)
                                        continue;
                                if (ci->ci_gmon->state != GMON_PROF_OFF) {
                                        prof_on = true;
                                        break;
                                }
                        }
                        mutex_spin_enter(&proc0.p_stmutex);
                        if (prof_on)
                                startprofclock(&proc0);
                        else
                                stopprofclock(&proc0);
                        mutex_spin_exit(&proc0.p_stmutex);

                        if (prof_on) {
                                _gmonparam.state = GMON_PROF_ON;
                        } else {
                                _gmonparam.state = GMON_PROF_OFF;
                                /*
                                 * when _gmonparam.state and all CPU gmon state
                                 * are OFF, all CPU states should be ON so that
                                 * the entire CPUs profiling can be controlled
                                 * by _gmonparam.state only.
                                 */
                                for (CPU_INFO_FOREACH(cii, ci)) {
                                        if (ci->ci_gmon == NULL)
                                                continue;
                                        ci->ci_gmon->state = GMON_PROF_ON;
                                }
                        }
                } else {
                        _gmonparam.state = state;
                        where = xc_broadcast(0, prof_set_state_xc,
                            UINT64TOPTR(state), NULL);
                        xc_wait(where);

                        mutex_spin_enter(&proc0.p_stmutex);
                        if (state == GMON_PROF_OFF)
                                stopprofclock(&proc0);
                        else
                                startprofclock(&proc0);
                        mutex_spin_exit(&proc0.p_stmutex);
                }
                break;
        case GPROF_COUNT:
                /*
                 * if 'kern.profiling.{count,froms,tos}' is written, the same
                 * data will be written to 'kern.profiling.percpu.cpuN.xxx'
                 */
                if (target_ci == NULL) {
                        for (CPU_INFO_FOREACH(cii, ci)) {
                                if (ci->ci_gmon == NULL)
                                        continue;
                                memmove(ci->ci_gmon->kcount, gp->kcount,
                                    newlen);
                        }
                }
                break;
        case GPROF_FROMS:
                if (target_ci == NULL) {
                        for (CPU_INFO_FOREACH(cii, ci)) {
                                if (ci->ci_gmon == NULL)
                                        continue;
                                memmove(ci->ci_gmon->froms, gp->froms, newlen);
                        }
                }
                break;
        case GPROF_TOS:
                if (target_ci == NULL) {
                        for (CPU_INFO_FOREACH(cii, ci)) {
                                if (ci->ci_gmon == NULL)
                                        continue;
                                memmove(ci->ci_gmon->tos, gp->tos, newlen);
                        }
                }
                break;
        }
#else
        if (node.sysctl_num == GPROF_STATE) {
                mutex_spin_enter(&proc0.p_stmutex);
                if (gp->state == GMON_PROF_OFF)
                        stopprofclock(&proc0);
                else
                        startprofclock(&proc0);
                mutex_spin_exit(&proc0.p_stmutex);
        }
#endif

 done:
#ifdef MULTIPROCESSOR
        if (do_merge)
                free(gp, M_GPROF);
#endif
        return error;
}

SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup")
{

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "profiling",
                       SYSCTL_DESCR("Profiling information (available)"),
                       NULL, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, CTL_EOL);

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "state",
                       SYSCTL_DESCR("Profiling state"),
                       sysctl_kern_profiling, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRUCT, "count",
                       SYSCTL_DESCR("Array of statistical program counters"),
                       sysctl_kern_profiling, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRUCT, "froms",
                       SYSCTL_DESCR("Array indexed by program counter of "
                                    "call-from points"),
                       sysctl_kern_profiling, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_STRUCT, "tos",
                       SYSCTL_DESCR("Array of structures describing "
                                    "destination of calls and their counts"),
                       sysctl_kern_profiling, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_STRUCT, "gmonparam",
                       SYSCTL_DESCR("Structure giving the sizes of the above "
                                    "arrays"),
                       sysctl_kern_profiling, 0, NULL, 0,
                       CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL);
}
#endif /* GPROF */

/*
 * Profiling system call.
 *
 * The scale factor is a fixed point number with 16 bits of fraction, so that
 * 1.0 is represented as 0x10000.  A scale factor of 0 turns off profiling.
 */
/* ARGSUSED */
int
sys_profil(struct lwp *l, const struct sys_profil_args *uap, register_t *retval)
{
        /* {
                syscallarg(char *) samples;
                syscallarg(size_t) size;
                syscallarg(u_long) offset;
                syscallarg(u_int) scale;
        } */
        struct proc *p = l->l_proc;
        struct uprof *upp;

        if (SCARG(uap, scale) > (1 << 16))
                return SET_ERROR(EINVAL);
        if (SCARG(uap, scale) == 0) {
                mutex_spin_enter(&p->p_stmutex);
                stopprofclock(p);
                mutex_spin_exit(&p->p_stmutex);
                return 0;
        }
        upp = &p->p_stats->p_prof;

        /* Block profile interrupts while changing state. */
        mutex_spin_enter(&p->p_stmutex);
        upp->pr_off = SCARG(uap, offset);
        upp->pr_scale = SCARG(uap, scale);
        upp->pr_base = SCARG(uap, samples);
        upp->pr_size = SCARG(uap, size);
        startprofclock(p);
        mutex_spin_exit(&p->p_stmutex);

        return 0;
}

/*
 * Scale is a fixed-point number with the binary point 16 bits
 * into the value, and is <= 1.0.  pc is at most 32 bits, so the
 * intermediate result is at most 48 bits.
 */
#define PC_TO_INDEX(pc, prof) \
        ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
            (u_quad_t)((prof)->pr_scale)) >> 16) & ~1)

/*
 * Collect user-level profiling statistics; called on a profiling tick,
 * when a process is running in user-mode.  This routine may be called
 * from an interrupt context.  We schedule an AST that will vector us
 * to trap() with a context in which copyin and copyout will work.
 * Trap will then call addupc_task().
 *
 * XXX We could use ufetch/ustore here if the profile buffers were
 * wired.
 *
 * Note that we may (rarely) not get around to the AST soon enough, and
 * lose profile ticks when the next tick overwrites this one, but in this
 * case the system is overloaded and the profile is probably already
 * inaccurate.
 */
void
addupc_intr(struct lwp *l, u_long pc)
{
        struct uprof *prof;
        struct proc *p;
        u_int i;

        p = l->l_proc;

        KASSERT(mutex_owned(&p->p_stmutex));

        prof = &p->p_stats->p_prof;
        if (pc < prof->pr_off ||
            (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size)
                return;                 /* out of range; ignore */

        mutex_spin_exit(&p->p_stmutex);

        /* XXXSMP */
        prof->pr_addr = pc;
        prof->pr_ticks++;
        cpu_need_proftick(l);

        mutex_spin_enter(&p->p_stmutex);
}

/*
 * Much like before, but we can afford to take faults here.  If the
 * update fails, we simply turn off profiling.
 */
void
addupc_task(struct lwp *l, u_long pc, u_int ticks)
{
        struct uprof *prof;
        struct proc *p;
        void *addr;
        int error;
        u_int i;
        u_short v;

        p = l->l_proc;

        if (ticks == 0)
                return;

        mutex_spin_enter(&p->p_stmutex);
        prof = &p->p_stats->p_prof;

        /* Testing P_PROFIL may be unnecessary, but is certainly safe. */
        if ((p->p_stflag & PST_PROFIL) == 0 || pc < prof->pr_off ||
            (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
                mutex_spin_exit(&p->p_stmutex);
                return;
        }

        addr = prof->pr_base + i;
        mutex_spin_exit(&p->p_stmutex);
        if ((error = copyin(addr, (void *)&v, sizeof(v))) == 0) {
                v += ticks;
                error = copyout((void *)&v, addr, sizeof(v));
        }
        if (error != 0) {
                mutex_spin_enter(&p->p_stmutex);
                stopprofclock(p);
                mutex_spin_exit(&p->p_stmutex);
        }
}