[apple/xnu.git] / bsd / kern / subr_prof.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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	8.3 (Berkeley) 9/23/93
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <machine/spl.h>

#include <sys/mount.h>

#include <kern/cpu_number.h>

#ifdef GPROF
#include <sys/malloc.h>
#include <sys/gmon.h>
#include <kern/mach_header.h>
#include <machine/profile.h>

decl_simple_lock_data(,mcount_lock);

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

kmstartup()
{
	char *cp;
	u_long	fromssize, tossize;
	struct segment_command		*sgp;
	struct gmonparam *p = &_gmonparam;
	
	sgp = getsegbyname("__TEXT");
	p->lowpc = (u_long)sgp->vmaddr;
	p->highpc = (u_long)(sgp->vmaddr + sgp->vmsize);
	
	/*
	 * 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(p->lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
	p->highpc = ROUNDUP(p->highpc, HISTFRACTION * sizeof(HISTCOUNTER));
	p->textsize = p->highpc - p->lowpc;
	printf("Profiling kernel, textsize=%d [0x%08x..0x%08x]\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);
	/* Why not use MALLOC with M_GPROF ? */
	cp = (char *)kalloc(p->kcountsize + p->fromssize + p->tossize);
	if (cp == 0) {
		printf("No memory for profiling.\n");
		return;
	}
	bzero(cp, p->kcountsize + p->tossize + p->fromssize);
	p->tos = (struct tostruct *)cp;
	cp += p->tossize;
	p->kcount = (u_short *)cp;
	cp += p->kcountsize;
	p->froms = (u_short *)cp;
	simple_lock_init(&mcount_lock);
}

/*
 * Return kernel profiling information.
 */
int
sysctl_doprof(name, namelen, oldp, oldlenp, newp, newlen)
	int *name;
	u_int namelen;
	void *oldp;
	size_t *oldlenp;
	void *newp;
	size_t newlen;
{
	struct gmonparam *gp = &_gmonparam;
	int error;

	/* all sysctl names at this level are terminal */
	if (namelen != 1)
		return (ENOTDIR);		/* overloaded */

	switch (name[0]) {
	case GPROF_STATE:
		error = sysctl_int(oldp, oldlenp, newp, newlen, &gp->state);
		if (error)
			return (error);
		if (gp->state == GMON_PROF_OFF)
			stopprofclock(kernproc);
		else
			startprofclock(kernproc);
		return (0);
	case GPROF_COUNT:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->kcount, gp->kcountsize));
	case GPROF_FROMS:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->froms, gp->fromssize));
	case GPROF_TOS:
		return (sysctl_struct(oldp, oldlenp, newp, newlen,
		    gp->tos, gp->tossize));
	case GPROF_GMONPARAM:
		return (sysctl_rdstruct(oldp, oldlenp, newp, gp, sizeof *gp));
	default:
		return (EOPNOTSUPP);
	}
	/* NOTREACHED */
}


/*
 * mcount() called with interrupts disabled.
 */
void
mcount(
    register u_long frompc,
    register u_long selfpc
)
{
    unsigned short *frompcindex;
	register struct tostruct *top, *prevtop;
	struct gmonparam *p = &_gmonparam;
	register long toindex;

    /*
     * check that we are profiling
     * and that we aren't recursively invoked.
     */
    if (p->state != GMON_PROF_ON)
        return;

	usimple_lock(&mcount_lock);

	/*
	 *	check that frompcindex is a reasonable pc value.
	 *	for example:	signal catchers get called from the stack,
	 *			not from text space.  too bad.
	 */
	frompc -= p->lowpc;
	if (frompc > p->textsize)
		goto done;

	frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))];
	toindex = *frompcindex;
	if (toindex == 0) {
		/*
		 *	first time traversing this arc
		 */
		toindex = ++p->tos[0].link;
		if (toindex >= p->tolimit) {
            /* halt further profiling */
			goto overflow;
		}
		*frompcindex = toindex;
		top = &p->tos[toindex];
		top->selfpc = selfpc;
		top->count = 1;
		top->link = 0;
		goto done;
	}
	top = &p->tos[toindex];
	if (top->selfpc == selfpc) {
		/*
		 *	arc at front of chain; usual case.
		 */
		top->count++;
		goto done;
	}
	/*
	 *	have to go looking down chain for it.
	 *	top points to what we are looking at,
	 *	prevtop points to previous top.
	 *	we know it is not at the head of the chain.
	 */
	for (; /* goto done */; ) {
		if (top->link == 0) {
			/*
			 *	top is end of the chain and none of the chain
			 *	had top->selfpc == selfpc.
			 *	so we allocate a new tostruct
			 *	and link it to the head of the chain.
			 */
			toindex = ++p->tos[0].link;
			if (toindex >= p->tolimit) {
				goto overflow;
			}
			top = &p->tos[toindex];
			top->selfpc = selfpc;
			top->count = 1;
			top->link = *frompcindex;
			*frompcindex = toindex;
			goto done;
		}
		/*
		 *	otherwise, check the next arc on the chain.
		 */
		prevtop = top;
		top = &p->tos[top->link];
		if (top->selfpc == selfpc) {
			/*
			 *	there it is.
			 *	increment its count
			 *	move it to the head of the chain.
			 */
			top->count++;
			toindex = prevtop->link;
			prevtop->link = top->link;
			top->link = *frompcindex;
			*frompcindex = toindex;
			goto done;
		}

	}
done:
	usimple_unlock(&mcount_lock);
	return;

overflow:
    p->state = GMON_PROF_ERROR;
        usimple_unlock(&mcount_lock);
	printf("mcount: tos overflow\n");
	return;
}

#endif /* GPROF */

#define PROFILE_LOCK(x)		simple_lock(x)
#define PROFILE_UNLOCK(x)	simple_unlock(x)

struct profil_args {
	short	*bufbase;
	u_int bufsize;
	u_int pcoffset;
	u_int pcscale;
};
int
profil(p, uap, retval)
	struct proc *p;
	register struct profil_args *uap;
	register_t *retval;
{
	register struct uprof *upp = &p->p_stats->p_prof;
	struct uprof *upc, *nupc;
	int s;

	if (uap->pcscale > (1 << 16))
		return (EINVAL);
	if (uap->pcscale == 0) {
		stopprofclock(p);
		return (0);
	}

	/* Block profile interrupts while changing state. */
        s = ml_set_interrupts_enabled(FALSE);	
	PROFILE_LOCK(&upp->pr_lock);
	upp->pr_base = (caddr_t)uap->bufbase;
	upp->pr_size = uap->bufsize;
	upp->pr_off = uap->pcoffset;
	upp->pr_scale = uap->pcscale;

	/* remove buffers previously allocated with add_profil() */
	for (upc = upp->pr_next; upc; upc = nupc) {
		nupc = upc->pr_next;
		kfree(upc, sizeof (struct uprof));
	}

	upp->pr_next = 0;
	PROFILE_UNLOCK(&upp->pr_lock);
	startprofclock(p);
	ml_set_interrupts_enabled(s);
	return(0);
}

struct add_profile_args {
	short	*bufbase;
	u_int bufsize;
	u_int pcoffset;
	u_int pcscale;
};
int
add_profil(p, uap, retval)
	struct proc *p;
	register struct add_profile_args *uap;
	register_t *retval;
{
	struct uprof *upp = &p->p_stats->p_prof, *upc;
	int s;

	if (upp->pr_scale == 0)
		return (0);
        s = ml_set_interrupts_enabled(FALSE);		
	upc = (struct uprof *) kalloc(sizeof (struct uprof));
	upc->pr_base = (caddr_t)uap->bufbase;
	upc->pr_size = uap->bufsize;
	upc->pr_off = uap->pcoffset;
	upc->pr_scale = uap->pcscale;
	PROFILE_LOCK(&upp->pr_lock);
	upc->pr_next = upp->pr_next;
	upp->pr_next = upc;
	PROFILE_UNLOCK(&upp->pr_lock);
	ml_set_interrupts_enabled(s);		
	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. We use
 * an AST that will vector us to trap() with a context in which copyin
 * and copyout will work.  Trap will then call addupc_task().
 *
 * 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.
 *
 * We can afford to take faults here.  If the
 * update fails, we simply turn off profiling.
 */
void
addupc_task(p, pc, ticks)
	register struct proc *p;
	register u_long pc;
	u_int ticks;
{
	register struct uprof *prof;
	register short *cell;
	register u_int off;
	u_short count;

	/* Testing P_PROFIL may be unnecessary, but is certainly safe. */
	if ((p->p_flag & P_PROFIL) == 0 || ticks == 0)
		return;

	for (prof = &p->p_stats->p_prof; prof; prof = prof->pr_next) {
		off = PC_TO_INDEX(pc,prof);
		cell = (short *)(prof->pr_base + off);
		if (cell >= (short *)prof->pr_base &&
			cell < (short*)(prof->pr_size + (int) prof->pr_base)) {
			if (copyin((caddr_t)cell, (caddr_t) &count, sizeof(count)) == 0) {
				count += ticks;
				if(copyout((caddr_t) &count, (caddr_t)cell, sizeof(count)) == 0)
					return;
			}
			p->p_stats->p_prof.pr_scale = 0;
			stopprofclock(p);
			break;
		}
	}
}
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
43866e37	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
1c79356b	7	*
43866e37 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
43866e37 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
1c79356b A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
	26	/*-
	27	* Copyright (c) 1982, 1986, 1993
	28	* The Regents of the University of California. All rights reserved.
	29	*
	30	* Redistribution and use in source and binary forms, with or without
	31	* modification, are permitted provided that the following conditions
	32	* are met:
	33	* 1. Redistributions of source code must retain the above copyright
	34	* notice, this list of conditions and the following disclaimer.
	35	* 2. Redistributions in binary form must reproduce the above copyright
	36	* notice, this list of conditions and the following disclaimer in the
	37	* documentation and/or other materials provided with the distribution.
	38	* 3. All advertising materials mentioning features or use of this software
	39	* must display the following acknowledgement:
	40	* This product includes software developed by the University of
	41	* California, Berkeley and its contributors.
	42	* 4. Neither the name of the University nor the names of its contributors
	43	* may be used to endorse or promote products derived from this software
	44	* without specific prior written permission.
	45	*
	46	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	47	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	48	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	49	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	50	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	51	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	52	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	53	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	54	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	55	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	56	* SUCH DAMAGE.
	57	*
	58	* @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
	59	*/
	60
	61	#include <sys/param.h>
	62	#include <sys/systm.h>
	63	#include <sys/kernel.h>
	64	#include <sys/proc.h>
	65	#include <sys/user.h>
	66	#include <machine/spl.h>
	67
	68	#include <sys/mount.h>
	69
	70	#include <kern/cpu_number.h>
	71
	72	#ifdef GPROF
	73	#include <sys/malloc.h>
	74	#include <sys/gmon.h>
	75	#include <kern/mach_header.h>
	76	#include <machine/profile.h>
	77
55e303ae A	78	decl_simple_lock_data(,mcount_lock);
55e303ae A	79
1c79356b A	80	/*
	81	* Froms is actually a bunch of unsigned shorts indexing tos
	82	*/
	83	struct gmonparam _gmonparam = { GMON_PROF_OFF };
	84
	85	kmstartup()
	86	{
	87	char *cp;
	88	u_long fromssize, tossize;
	89	struct segment_command *sgp;
	90	struct gmonparam *p = &_gmonparam;
	91
	92	sgp = getsegbyname("__TEXT");
	93	p->lowpc = (u_long)sgp->vmaddr;
	94	p->highpc = (u_long)(sgp->vmaddr + sgp->vmsize);
	95
	96	/*
	97	* Round lowpc and highpc to multiples of the density we're using
	98	* so the rest of the scaling (here and in gprof) stays in ints.
	99	*/
	100	p->lowpc = ROUNDDOWN(p->lowpc, HISTFRACTION * sizeof(HISTCOUNTER));
	101	p->highpc = ROUNDUP(p->highpc, HISTFRACTION * sizeof(HISTCOUNTER));
	102	p->textsize = p->highpc - p->lowpc;
	103	printf("Profiling kernel, textsize=%d [0x%08x..0x%08x]\n",
	104	p->textsize, p->lowpc, p->highpc);
	105	p->kcountsize = p->textsize / HISTFRACTION;
	106	p->hashfraction = HASHFRACTION;
	107	p->fromssize = p->textsize / HASHFRACTION;
	108	p->tolimit = p->textsize * ARCDENSITY / 100;
	109	if (p->tolimit < MINARCS)
	110	p->tolimit = MINARCS;
	111	else if (p->tolimit > MAXARCS)
	112	p->tolimit = MAXARCS;
	113	p->tossize = p->tolimit * sizeof(struct tostruct);
	114	/* Why not use MALLOC with M_GPROF ? */
	115	cp = (char *)kalloc(p->kcountsize + p->fromssize + p->tossize);
	116	if (cp == 0) {
	117	printf("No memory for profiling.\n");
	118	return;
	119	}
	120	bzero(cp, p->kcountsize + p->tossize + p->fromssize);
	121	p->tos = (struct tostruct *)cp;
	122	cp += p->tossize;
	123	p->kcount = (u_short *)cp;
	124	cp += p->kcountsize;
	125	p->froms = (u_short *)cp;
55e303ae	126	simple_lock_init(&mcount_lock);
1c79356b A	127	}
	128
	129	/*
	130	* Return kernel profiling information.
	131	*/
9bccf70c A	132	int
9bccf70c A	133	sysctl_doprof(name, namelen, oldp, oldlenp, newp, newlen)
1c79356b A	134	int *name;
	135	u_int namelen;
	136	void *oldp;
	137	size_t *oldlenp;
	138	void *newp;
	139	size_t newlen;
	140	{
	141	struct gmonparam *gp = &_gmonparam;
	142	int error;
	143
	144	/* all sysctl names at this level are terminal */
	145	if (namelen != 1)
	146	return (ENOTDIR); /* overloaded */
	147
	148	switch (name[0]) {
	149	case GPROF_STATE:
	150	error = sysctl_int(oldp, oldlenp, newp, newlen, &gp->state);
	151	if (error)
	152	return (error);
	153	if (gp->state == GMON_PROF_OFF)
	154	stopprofclock(kernproc);
	155	else
	156	startprofclock(kernproc);
	157	return (0);
	158	case GPROF_COUNT:
	159	return (sysctl_struct(oldp, oldlenp, newp, newlen,
	160	gp->kcount, gp->kcountsize));
	161	case GPROF_FROMS:
	162	return (sysctl_struct(oldp, oldlenp, newp, newlen,
	163	gp->froms, gp->fromssize));
	164	case GPROF_TOS:
	165	return (sysctl_struct(oldp, oldlenp, newp, newlen,
	166	gp->tos, gp->tossize));
	167	case GPROF_GMONPARAM:
	168	return (sysctl_rdstruct(oldp, oldlenp, newp, gp, sizeof *gp));
	169	default:
	170	return (EOPNOTSUPP);
	171	}
	172	/* NOTREACHED */
	173	}
	174
	175
	176	/*
	177	* mcount() called with interrupts disabled.
	178	*/
	179	void
	180	mcount(
	181	register u_long frompc,
	182	register u_long selfpc
	183	)
	184	{
	185	unsigned short *frompcindex;
	186	register struct tostruct top, prevtop;
	187	struct gmonparam *p = &_gmonparam;
	188	register long toindex;
1c79356b A	189
	190	/*
	191	* check that we are profiling
	192	* and that we aren't recursively invoked.
	193	*/
	194	if (p->state != GMON_PROF_ON)
	195	return;
	196
55e303ae	197	usimple_lock(&mcount_lock);
1c79356b A	198
	199	/*
	200	* check that frompcindex is a reasonable pc value.
	201	* for example: signal catchers get called from the stack,
	202	* not from text space. too bad.
	203	*/
	204	frompc -= p->lowpc;
	205	if (frompc > p->textsize)
	206	goto done;
	207
	208	frompcindex = &p->froms[frompc / (p->hashfraction * sizeof(*p->froms))];
	209	toindex = *frompcindex;
	210	if (toindex == 0) {
	211	/*
	212	* first time traversing this arc
	213	*/
	214	toindex = ++p->tos[0].link;
	215	if (toindex >= p->tolimit) {
	216	/* halt further profiling */
	217	goto overflow;
	218	}
	219	*frompcindex = toindex;
	220	top = &p->tos[toindex];
	221	top->selfpc = selfpc;
	222	top->count = 1;
	223	top->link = 0;
	224	goto done;
	225	}
	226	top = &p->tos[toindex];
	227	if (top->selfpc == selfpc) {
	228	/*
	229	* arc at front of chain; usual case.
	230	*/
	231	top->count++;
	232	goto done;
	233	}
	234	/*
	235	* have to go looking down chain for it.
	236	* top points to what we are looking at,
	237	* prevtop points to previous top.
	238	* we know it is not at the head of the chain.
	239	*/
	240	for (; /* goto done */; ) {
	241	if (top->link == 0) {
	242	/*
	243	* top is end of the chain and none of the chain
	244	* had top->selfpc == selfpc.
	245	* so we allocate a new tostruct
	246	* and link it to the head of the chain.
	247	*/
	248	toindex = ++p->tos[0].link;
	249	if (toindex >= p->tolimit) {
	250	goto overflow;
	251	}
	252	top = &p->tos[toindex];
	253	top->selfpc = selfpc;
	254	top->count = 1;
	255	top->link = *frompcindex;
	256	*frompcindex = toindex;
	257	goto done;
	258	}
	259	/*
	260	* otherwise, check the next arc on the chain.
	261	*/
262	prevtop = top;
263	top = &p->tos[top->link];
264	if (top->selfpc == selfpc) {
265	/*
266	* there it is.
267	* increment its count
268	* move it to the head of the chain.
269	*/
270	top->count++;
271	toindex = prevtop->link;
272	prevtop->link = top->link;
273	top->link = *frompcindex;
274	*frompcindex = toindex;
275	goto done;
276	}
277
278	}
279	done:
55e303ae	280	usimple_unlock(&mcount_lock);
1c79356b A	281	return;
	282
	283	overflow:
	284	p->state = GMON_PROF_ERROR;
55e303ae	285	usimple_unlock(&mcount_lock);
1c79356b A	286	printf("mcount: tos overflow\n");
	287	return;
	288	}
	289
	290	#endif /* GPROF */
	291
1c79356b A	292	#define PROFILE_LOCK(x) simple_lock(x)
1c79356b A	293	#define PROFILE_UNLOCK(x) simple_unlock(x)
1c79356b A	294
	295	struct profil_args {
	296	short *bufbase;
	297	u_int bufsize;
	298	u_int pcoffset;
	299	u_int pcscale;
	300	};
	301	int
	302	profil(p, uap, retval)
	303	struct proc *p;
	304	register struct profil_args *uap;
	305	register_t *retval;
	306	{
	307	register struct uprof *upp = &p->p_stats->p_prof;
	308	struct uprof upc, nupc;
	309	int s;
	310
	311	if (uap->pcscale > (1 << 16))
	312	return (EINVAL);
	313	if (uap->pcscale == 0) {
	314	stopprofclock(p);
	315	return (0);
	316	}
	317
	318	/* Block profile interrupts while changing state. */
55e303ae	319	s = ml_set_interrupts_enabled(FALSE);
1c79356b A	320	PROFILE_LOCK(&upp->pr_lock);
	321	upp->pr_base = (caddr_t)uap->bufbase;
	322	upp->pr_size = uap->bufsize;
	323	upp->pr_off = uap->pcoffset;
	324	upp->pr_scale = uap->pcscale;
	325
	326	/* remove buffers previously allocated with add_profil() */
	327	for (upc = upp->pr_next; upc; upc = nupc) {
	328	nupc = upc->pr_next;
	329	kfree(upc, sizeof (struct uprof));
	330	}
	331
	332	upp->pr_next = 0;
	333	PROFILE_UNLOCK(&upp->pr_lock);
	334	startprofclock(p);
55e303ae	335	ml_set_interrupts_enabled(s);
1c79356b A	336	return(0);
	337	}
	338
	339	struct add_profile_args {
	340	short *bufbase;
	341	u_int bufsize;
	342	u_int pcoffset;
	343	u_int pcscale;
	344	};
	345	int
	346	add_profil(p, uap, retval)
	347	struct proc *p;
	348	register struct add_profile_args *uap;
	349	register_t *retval;
	350	{
	351	struct uprof upp = &p->p_stats->p_prof, upc;
	352	int s;
	353
	354	if (upp->pr_scale == 0)
	355	return (0);
55e303ae	356	s = ml_set_interrupts_enabled(FALSE);
1c79356b A	357	upc = (struct uprof *) kalloc(sizeof (struct uprof));
	358	upc->pr_base = (caddr_t)uap->bufbase;
	359	upc->pr_size = uap->bufsize;
	360	upc->pr_off = uap->pcoffset;
	361	upc->pr_scale = uap->pcscale;
	362	PROFILE_LOCK(&upp->pr_lock);
	363	upc->pr_next = upp->pr_next;
	364	upp->pr_next = upc;
	365	PROFILE_UNLOCK(&upp->pr_lock);
55e303ae	366	ml_set_interrupts_enabled(s);
1c79356b A	367	return(0);
	368	}
	369
	370	/*
	371	* Scale is a fixed-point number with the binary point 16 bits
	372	* into the value, and is <= 1.0. pc is at most 32 bits, so the
	373	* intermediate result is at most 48 bits.
	374	*/
	375	#define PC_TO_INDEX(pc, prof) \
	376	((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
	377	(u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
	378
	379	/*
	380	* Collect user-level profiling statistics; called on a profiling tick,
	381	* when a process is running in user-mode. We use
	382	* an AST that will vector us to trap() with a context in which copyin
	383	* and copyout will work. Trap will then call addupc_task().
	384	*
	385	* Note that we may (rarely) not get around to the AST soon enough, and
	386	* lose profile ticks when the next tick overwrites this one, but in this
	387	* case the system is overloaded and the profile is probably already
	388	* inaccurate.
	389	*
	390	* We can afford to take faults here. If the
	391	* update fails, we simply turn off profiling.
	392	*/
	393	void
	394	addupc_task(p, pc, ticks)
	395	register struct proc *p;
	396	register u_long pc;
	397	u_int ticks;
	398	{
	399	register struct uprof *prof;
	400	register short *cell;
	401	register u_int off;
	402	u_short count;
	403
	404	/* Testing P_PROFIL may be unnecessary, but is certainly safe. */
	405	if ((p->p_flag & P_PROFIL) == 0 \|\| ticks == 0)
	406	return;
	407
	408	for (prof = &p->p_stats->p_prof; prof; prof = prof->pr_next) {
	409	off = PC_TO_INDEX(pc,prof);
	410	cell = (short *)(prof->pr_base + off);
	411	if (cell >= (short *)prof->pr_base &&
	412	cell < (short*)(prof->pr_size + (int) prof->pr_base)) {
	413	if (copyin((caddr_t)cell, (caddr_t) &count, sizeof(count)) == 0) {
	414	count += ticks;
	415	if(copyout((caddr_t) &count, (caddr_t)cell, sizeof(count)) == 0)
	416	return;
	417	}
	418	p->p_stats->p_prof.pr_scale = 0;
	419	stopprofclock(p);
	420	break;
	421	}
	422	}
	423	}