Annotation of Net2/kern/subr_mcount.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1982, 1986 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer in the
                     12:  *    documentation and/or other materials provided with the distribution.
                     13:  * 3. All advertising materials mentioning features or use of this software
                     14:  *    must display the following acknowledgement:
                     15:  *     This product includes software developed by the University of
                     16:  *     California, Berkeley and its contributors.
                     17:  * 4. Neither the name of the University nor the names of its contributors
                     18:  *    may be used to endorse or promote products derived from this software
                     19:  *    without specific prior written permission.
                     20:  *
                     21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     31:  * SUCH DAMAGE.
                     32:  *
                     33:  *     @(#)subr_mcount.c       7.10 (Berkeley) 5/7/91
                     34:  */
                     35: 
                     36: #ifdef GPROF
                     37: #include "gprof.h"
                     38: #include "param.h"
                     39: #include "systm.h"
                     40: #include "malloc.h"
                     41: 
                     42: /*
                     43:  * Froms is actually a bunch of unsigned shorts indexing tos
                     44:  */
                     45: int    profiling = 3;
                     46: u_short        *froms;
                     47: struct tostruct *tos = 0;
                     48: long   tolimit = 0;
                     49: char   *s_lowpc = (char *)KERNBASE;
                     50: extern char etext;
                     51: char   *s_highpc = &etext;
                     52: u_long s_textsize = 0;
                     53: int    ssiz;
                     54: u_short        *sbuf;
                     55: u_short        *kcount;
                     56: 
                     57: kmstartup()
                     58: {
                     59:        u_long fromssize, tossize;
                     60: 
                     61:        /*
                     62:         * Round lowpc and highpc to multiples of the density we're using
                     63:         * so the rest of the scaling (here and in gprof) stays in ints.
                     64:         */
                     65:        s_lowpc = (char *)
                     66:            ROUNDDOWN((unsigned)s_lowpc, HISTFRACTION*sizeof (HISTCOUNTER));
                     67:        s_highpc = (char *)
                     68:            ROUNDUP((unsigned)s_highpc, HISTFRACTION*sizeof (HISTCOUNTER));
                     69:        s_textsize = s_highpc - s_lowpc;
                     70:        printf("Profiling kernel, s_textsize=%d [%x..%x]\n",
                     71:                s_textsize, s_lowpc, s_highpc);
                     72:        ssiz = (s_textsize / HISTFRACTION) + sizeof (struct phdr);
                     73:        sbuf = (u_short *)malloc(ssiz, M_GPROF, M_WAITOK);
                     74:        if (sbuf == 0) {
                     75:                printf("No space for monitor buffer(s)\n");
                     76:                return;
                     77:        }
                     78:        bzero(sbuf, ssiz);
                     79:        fromssize = s_textsize / HASHFRACTION;
                     80:        froms = (u_short *)malloc(fromssize, M_GPROF, M_NOWAIT);
                     81:        if (froms == 0) {
                     82:                printf("No space for monitor buffer(s)\n");
                     83:                free(sbuf, M_GPROF);
                     84:                sbuf = 0;
                     85:                return;
                     86:        }
                     87:        bzero(froms, fromssize);
                     88:        tolimit = s_textsize * ARCDENSITY / 100;
                     89:        if (tolimit < MINARCS)
                     90:                tolimit = MINARCS;
                     91:        else if (tolimit > (0xffff - 1))
                     92:                tolimit = 0xffff - 1;
                     93:        tossize = tolimit * sizeof (struct tostruct);
                     94:        tos = (struct tostruct *)malloc(tossize, M_GPROF, M_WAITOK);
                     95:        if (tos == 0) {
                     96:                printf("No space for monitor buffer(s)\n");
                     97:                free(sbuf, M_GPROF), sbuf = 0;
                     98:                free(froms, M_GPROF), froms = 0;
                     99:                return;
                    100:        }
                    101:        bzero(tos, tossize);
                    102:        tos[0].link = 0;
                    103:        ((struct phdr *)sbuf)->lpc = s_lowpc;
                    104:        ((struct phdr *)sbuf)->hpc = s_highpc;
                    105:        ((struct phdr *)sbuf)->ncnt = ssiz;
                    106:        kcount = (u_short *)(((int)sbuf) + sizeof (struct phdr));
                    107: }
                    108: 
                    109: /*
                    110:  * This routine is massaged so that it may be jsb'ed to on vax.
                    111:  */
                    112: asm(".text");
                    113: asm("#the beginning of mcount()");
                    114: asm(".data");
                    115: mcount()
                    116: {
                    117:        register char *selfpc;                  /* r11 => r5 */
                    118:        register u_short *frompcindex;          /* r10 => r4 */
                    119:        register struct tostruct *top;          /* r9  => r3 */
                    120:        register struct tostruct *prevtop;      /* r8  => r2 */
                    121:        register long toindex;                  /* r7  => r1 */
                    122:        static int s;
                    123: 
                    124:        asm("   .text");                /* make sure we're in text space */
                    125:        /*
                    126:         * Check that we are profiling.
                    127:         */
                    128:        if (profiling)
                    129:                goto out;
                    130:        /*
                    131:         * Find the return address for mcount,
                    132:         * and the return address for mcount's caller.
                    133:         */
                    134: #ifdef lint
                    135:        selfpc = (char *)0;
                    136:        frompcindex = 0;
                    137: #else
                    138:        ;                               /* avoid label botch */
                    139: #ifdef __GNUC__
                    140: #if defined(vax)
                    141:        Fix Me!!
                    142: #endif
                    143: #if defined(tahoe)
                    144:        Fix Me!!
                    145: #endif
                    146: #if defined(hp300)
                    147:        /*
                    148:         * selfpc = pc pushed by mcount jsr,
                    149:         * frompcindex = pc pushed by jsr into self.
                    150:         * In GCC the caller's stack frame has already been built so we
                    151:         * have to chase a6 to find caller's raddr.  This assumes that all
                    152:         * routines we are profiling were built with GCC and that all
                    153:         * profiled routines use link/unlk.
                    154:         */
                    155:        asm("movl a6@(4),%0" : "=r" (selfpc));
                    156:        asm("movl a6@(0)@(4),%0" : "=r" (frompcindex));
                    157: #endif
                    158: #else
                    159: #if defined(vax)
                    160:        asm("   movl (sp), r11");       /* selfpc = ... (jsb frame) */
                    161:        asm("   movl 16(fp), r10");     /* frompcindex =     (calls frame) */
                    162: #endif
                    163: #if defined(tahoe)
                    164:        asm("   movl -8(fp),r12");      /* selfpc = callf frame */
                    165:        asm("   movl (fp),r11");
                    166:        asm("   movl -8(r11),r11");     /* frompcindex = 1 callf frame back */
                    167: #endif
                    168: #if defined(hp300)
                    169:        Fix Me!!
                    170: #endif
                    171: #endif /* not __GNUC__ */
                    172: #endif /* not lint */
                    173:        /*
                    174:         * Insure that we cannot be recursively invoked.
                    175:         * this requires that splhigh() and splx() below
                    176:         * do NOT call mcount!
                    177:         */
                    178: #if defined(hp300)
                    179:        asm("movw       sr,%0" : "=g" (s));
                    180:        asm("movw       #0x2700,sr");
                    181: #else
                    182:        s = splhigh();
                    183: #endif
                    184:        /*
                    185:         * Check that frompcindex is a reasonable pc value.
                    186:         * For example: signal catchers get called from the stack,
                    187:         *      not from text space.  too bad.
                    188:         */
                    189:        frompcindex = (u_short *)((long)frompcindex - (long)s_lowpc);
                    190:        if ((u_long)frompcindex > s_textsize)
                    191:                goto done;
                    192:        frompcindex =
                    193:            &froms[((long)frompcindex) / (HASHFRACTION * sizeof (*froms))];
                    194:        toindex = *frompcindex;
                    195:        if (toindex == 0) {
                    196:                /*
                    197:                 * First time traversing this arc
                    198:                 */
                    199:                toindex = ++tos[0].link;
                    200:                if (toindex >= tolimit)
                    201:                        goto overflow;
                    202:                *frompcindex = toindex;
                    203:                top = &tos[toindex];
                    204:                top->selfpc = selfpc;
                    205:                top->count = 1;
                    206:                top->link = 0;
                    207:                goto done;
                    208:        }
                    209:        top = &tos[toindex];
                    210:        if (top->selfpc == selfpc) {
                    211:                /*
                    212:                 * Arc at front of chain; usual case.
                    213:                 */
                    214:                top->count++;
                    215:                goto done;
                    216:        }
                    217:        /*
                    218:         * Have to go looking down chain for it.
                    219:         * Top points to what we are looking at,
                    220:         * prevtop points to previous top.
                    221:         * We know it is not at the head of the chain.
                    222:         */
                    223:        for (; /* goto done */; ) {
                    224:                if (top->link == 0) {
                    225:                        /*
                    226:                         * Top is end of the chain and none of the chain
                    227:                         * had top->selfpc == selfpc.
                    228:                         * So we allocate a new tostruct
                    229:                         * and link it to the head of the chain.
                    230:                         */
                    231:                        toindex = ++tos[0].link;
                    232:                        if (toindex >= tolimit)
                    233:                                goto overflow;
                    234:                        top = &tos[toindex];
                    235:                        top->selfpc = selfpc;
                    236:                        top->count = 1;
                    237:                        top->link = *frompcindex;
                    238:                        *frompcindex = toindex;
                    239:                        goto done;
                    240:                }
                    241:                /*
                    242:                 * Otherwise, check the next arc on the chain.
                    243:                 */
                    244:                prevtop = top;
                    245:                top = &tos[top->link];
                    246:                if (top->selfpc == selfpc) {
                    247:                        /*
                    248:                         * There it is, increment its count and
                    249:                         * move it to the head of the chain.
                    250:                         */
                    251:                        top->count++;
                    252:                        toindex = prevtop->link;
                    253:                        prevtop->link = top->link;
                    254:                        top->link = *frompcindex;
                    255:                        *frompcindex = toindex;
                    256:                        goto done;
                    257:                }
                    258: 
                    259:        }
                    260: done:
                    261: #if defined(hp300)
                    262:        asm("movw       %0,sr" : : "g" (s));
                    263: #else
                    264:        splx(s);
                    265: #endif
                    266:        /* and fall through */
                    267: out:
                    268: #if defined(vax)
                    269:        asm("   rsb");
                    270: #endif
                    271:        return;
                    272: overflow:
                    273:        profiling = 3;
                    274:        printf("mcount: tos overflow\n");
                    275:        goto out;
                    276: }
                    277: asm(".text");
                    278: asm("#the end of mcount()");
                    279: asm(".data");
                    280: #endif

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