/*      $NetBSD: subr_prof.c,v 1.50 2021/08/14 17:51:20 ryo 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 1.50 2021/08/14 17:51:20 ryo Exp $");

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

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

#include <sys/cpu.h>

#ifdef GPROF
#include <sys/malloc.h>
#include <sys/gmon.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 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 (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 (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);
       }
}