Source to kern/subr_mcount.c


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/*
 * Copyright (c) 1982, 1986 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.
 *
 *	from: @(#)subr_mcount.c	7.10 (Berkeley) 5/7/91
 *	subr_mcount.c,v 1.3 1993/05/20 02:54:56 cgd Exp
 */

#ifdef GPROF
#include "gprof.h"
#include "param.h"
#include "systm.h"
#include "malloc.h"

/*
 * Froms is actually a bunch of unsigned shorts indexing tos
 */
int	profiling = 3;
u_short	*froms;
struct	tostruct *tos = 0;
long	tolimit = 0;
char	*s_lowpc = (char *)KERNBASE;
extern	char etext;
char	*s_highpc = &etext;
u_long	s_textsize = 0;
int	ssiz;
u_short	*sbuf;
u_short	*kcount;

kmstartup()
{
	u_long fromssize, tossize;

	/*
	 * 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.
	 */
	s_lowpc = (char *)
	    ROUNDDOWN((unsigned)s_lowpc, HISTFRACTION*sizeof (HISTCOUNTER));
	s_highpc = (char *)
	    ROUNDUP((unsigned)s_highpc, HISTFRACTION*sizeof (HISTCOUNTER));
	s_textsize = s_highpc - s_lowpc;
	printf("Profiling kernel, s_textsize=%d [%x..%x]\n",
		s_textsize, s_lowpc, s_highpc);
	ssiz = (s_textsize / HISTFRACTION) + sizeof (struct phdr);
	sbuf = (u_short *)malloc(ssiz, M_GPROF, M_WAITOK);
	if (sbuf == 0) {
		printf("No space for monitor buffer(s)\n");
		return;
	}
	bzero(sbuf, ssiz);
	fromssize = s_textsize / HASHFRACTION;
	froms = (u_short *)malloc(fromssize, M_GPROF, M_NOWAIT);
	if (froms == 0) {
		printf("No space for monitor buffer(s)\n");
		free(sbuf, M_GPROF);
		sbuf = 0;
		return;
	}
	bzero(froms, fromssize);
	tolimit = s_textsize * ARCDENSITY / 100;
	if (tolimit < MINARCS)
		tolimit = MINARCS;
	else if (tolimit > (0xffff - 1))
		tolimit = 0xffff - 1;
	tossize = tolimit * sizeof (struct tostruct);
	tos = (struct tostruct *)malloc(tossize, M_GPROF, M_WAITOK);
	if (tos == 0) {
		printf("No space for monitor buffer(s)\n");
		free(sbuf, M_GPROF), sbuf = 0;
		free(froms, M_GPROF), froms = 0;
		return;
	}
	bzero(tos, tossize);
	tos[0].link = 0;
	((struct phdr *)sbuf)->lpc = s_lowpc;
	((struct phdr *)sbuf)->hpc = s_highpc;
	((struct phdr *)sbuf)->ncnt = ssiz;
	kcount = (u_short *)(((int)sbuf) + sizeof (struct phdr));
}

mcount()
{
	register char *selfpc;			/* r11 => r5 */
	register u_short *frompcindex;		/* r10 => r4 */
	register struct tostruct *top;		/* r9  => r3 */
	register struct tostruct *prevtop;	/* r8  => r2 */
	register long toindex;			/* r7  => r1 */
	static int s;

	/*
	 * Check that we are profiling.
	 */
	if (profiling)
		goto out;
	/*
	 * Find the return address for mcount,
	 * and the return address for mcount's caller.
	 */
#ifdef lint
	selfpc = (char *)0;
	frompcindex = 0;
#else
	;				/* avoid label botch */
#ifdef __GNUC__
#if defined(vax)
	Fix Me!!
#endif
#if defined(tahoe)
	Fix Me!!
#endif
#if defined(hp300)
	/*
	 * selfpc = pc pushed by mcount jsr,
	 * frompcindex = pc pushed by jsr into self.
	 * In GCC the caller's stack frame has already been built so we
	 * have to chase a6 to find caller's raddr.  This assumes that all
	 * routines we are profiling were built with GCC and that all
	 * profiled routines use link/unlk.
	 */
	asm("movl [email protected](4),%0" : "=r" (selfpc));
	asm("movl [email protected](0)@(4),%0" : "=r" (frompcindex));
#endif
#if defined(i386)
        /*
         * selfpc = pc pushed by mcount call
         */
        asm("movl 4(%%ebp),%0" : "=r" (selfpc));
        /*
         * frompcindex = pc pushed by jsr into self.
         * in GCC, the caller's stack frame has already been built, so we
         * have to chase the base pointer to find caller's raddr.
         */
        asm("movl (%%ebp),%0" : "=r" (frompcindex));
        frompcindex = ((unsigned short **)frompcindex)[1];
#endif /* i386 */
#else
#if defined(vax)
	asm("	movl (sp), r11");	/* selfpc = ... (jsb frame) */
	asm("	movl 16(fp), r10");	/* frompcindex =     (calls frame) */
#endif
#if defined(i386)
	Fix Me!!
#endif /* i386 */
#if defined(tahoe)
	asm("	movl -8(fp),r12");	/* selfpc = callf frame */
	asm("	movl (fp),r11");
	asm("	movl -8(r11),r11");	/* frompcindex = 1 callf frame back */
#endif
#if defined(hp300)
	Fix Me!!
#endif
#endif /* not __GNUC__ */
#endif /* not lint */
	/*
	 * Insure that we cannot be recursively invoked.
	 * this requires that splhigh() and splx() below
	 * do NOT call mcount!
	 */
#if defined(hp300)
	asm("movw	sr,%0" : "=g" (s));
	asm("movw	#0x2700,sr");
#else
	s = splhigh();
#endif
	/*
	 * Check that frompcindex is a reasonable pc value.
	 * For example:	signal catchers get called from the stack,
	 *	not from text space.  too bad.
	 */
	frompcindex = (u_short *)((u_long)frompcindex - (u_long)s_lowpc);
	if ((u_long)frompcindex > s_textsize)
		goto done;
	frompcindex =
	    &froms[((long)frompcindex) / (HASHFRACTION * sizeof (*froms))];
	toindex = *frompcindex;
	if (toindex == 0) {
		/*
		 * First time traversing this arc
		 */
		toindex = ++tos[0].link;
		if (toindex >= tolimit)
			goto overflow;
		*frompcindex = toindex;
		top = &tos[toindex];
		top->selfpc = selfpc;
		top->count = 1;
		top->link = 0;
		goto done;
	}
	top = &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 = ++tos[0].link;
			if (toindex >= tolimit)
				goto overflow;
			top = &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 = &tos[top->link];
		if (top->selfpc == selfpc) {
			/*
			 * There it is, increment its count and
			 * 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:
#if defined(hp300)
	asm("movw	%0,sr" : : "g" (s));
#else
	splx(s);
#endif
	/* and fall through */
out:
#if defined(vax)
	asm("	rsb");
#endif
	return;
overflow:
	profiling = 3;
	printf("mcount: tos overflow\n");
	goto out;
}
#endif