1/*- 2 * Copyright (c) 1983, 1992, 1993 3 * The Regents of the University of California. 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 *
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33 * $FreeBSD: head/sys/libkern/mcount.c 50477 1999-08-28 01:08:13Z peter $
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33 * $FreeBSD: head/sys/libkern/mcount.c 55206 1999-12-29 05:07:58Z peter $ |
34 */ 35 36#include <sys/param.h> 37#include <sys/gmon.h>
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38#ifdef KERNEL
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38#ifdef _KERNEL |
39#ifndef GUPROF 40#include <sys/systm.h> 41#endif 42#include <vm/vm.h> 43#include <vm/vm_param.h> 44#include <vm/pmap.h> 45void bintr __P((void)); 46void btrap __P((void)); 47void eintr __P((void)); 48void user __P((void)); 49#endif 50 51/* 52 * mcount is called on entry to each function compiled with the profiling 53 * switch set. _mcount(), which is declared in a machine-dependent way 54 * with _MCOUNT_DECL, does the actual work and is either inlined into a 55 * C routine or called by an assembly stub. In any case, this magic is 56 * taken care of by the MCOUNT definition in <machine/profile.h>. 57 * 58 * _mcount updates data structures that represent traversals of the 59 * program's call graph edges. frompc and selfpc are the return 60 * address and function address that represents the given call graph edge. 61 * 62 * Note: the original BSD code used the same variable (frompcindex) for 63 * both frompcindex and frompc. Any reasonable, modern compiler will 64 * perform this optimization. 65 */ 66_MCOUNT_DECL(frompc, selfpc) /* _mcount; may be static, inline, etc */ 67 register uintfptr_t frompc, selfpc; 68{ 69#ifdef GUPROF 70 int delta; 71#endif 72 register fptrdiff_t frompci; 73 register u_short *frompcindex; 74 register struct tostruct *top, *prevtop; 75 register struct gmonparam *p; 76 register long toindex;
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77#ifdef KERNEL
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77#ifdef _KERNEL |
78 MCOUNT_DECL(s) 79#endif 80 81 p = &_gmonparam; 82#ifndef GUPROF /* XXX */ 83 /* 84 * check that we are profiling 85 * and that we aren't recursively invoked. 86 */ 87 if (p->state != GMON_PROF_ON) 88 return; 89#endif
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90#ifdef KERNEL
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90#ifdef _KERNEL |
91 MCOUNT_ENTER(s); 92#else 93 p->state = GMON_PROF_BUSY; 94#endif 95 frompci = frompc - p->lowpc; 96
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97#ifdef KERNEL
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97#ifdef _KERNEL |
98 /* 99 * When we are called from an exception handler, frompci may be 100 * for a user address. Convert such frompci's to the index of 101 * user() to merge all user counts. 102 */ 103 if (frompci >= p->textsize) { 104 if (frompci + p->lowpc 105 >= (uintfptr_t)(VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE)) 106 goto done; 107 frompci = (uintfptr_t)user - p->lowpc; 108 if (frompci >= p->textsize) 109 goto done; 110 }
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111#endif /* KERNEL */
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111#endif |
112 113#ifdef GUPROF 114 if (p->state == GMON_PROF_HIRES) { 115 /* 116 * Count the time since cputime() was previously called 117 * against `frompc'. Compensate for overheads. 118 * 119 * cputime() sets its prev_count variable to the count when 120 * it is called. This in effect starts a counter for 121 * the next period of execution (normally from now until 122 * the next call to mcount() or mexitcount()). We set 123 * cputime_bias to compensate for our own overhead. 124 * 125 * We use the usual sampling counters since they can be 126 * located efficiently. 4-byte counters are usually 127 * necessary. gprof will add up the scattered counts 128 * just like it does for statistical profiling. All 129 * counts are signed so that underflow in the subtractions 130 * doesn't matter much (negative counts are normally 131 * compensated for by larger counts elsewhere). Underflow 132 * shouldn't occur, but may be caused by slightly wrong 133 * calibrations or from not clearing cputime_bias. 134 */ 135 delta = cputime() - cputime_bias - p->mcount_pre_overhead; 136 cputime_bias = p->mcount_post_overhead; 137 KCOUNT(p, frompci) += delta; 138 *p->cputime_count += p->cputime_overhead; 139 *p->mcount_count += p->mcount_overhead; 140 } 141#endif /* GUPROF */ 142
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143#ifdef KERNEL
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143#ifdef _KERNEL |
144 /* 145 * When we are called from an exception handler, frompc is faked 146 * to be for where the exception occurred. We've just solidified 147 * the count for there. Now convert frompci to the index of btrap() 148 * for trap handlers and bintr() for interrupt handlers to make 149 * exceptions appear in the call graph as calls from btrap() and 150 * bintr() instead of calls from all over. 151 */ 152 if ((uintfptr_t)selfpc >= (uintfptr_t)btrap 153 && (uintfptr_t)selfpc < (uintfptr_t)eintr) { 154 if ((uintfptr_t)selfpc >= (uintfptr_t)bintr) 155 frompci = (uintfptr_t)bintr - p->lowpc; 156 else 157 frompci = (uintfptr_t)btrap - p->lowpc; 158 }
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159#endif /* KERNEL */
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159#endif |
160 161 /* 162 * check that frompc is a reasonable pc value. 163 * for example: signal catchers get called from the stack, 164 * not from text space. too bad. 165 */ 166 if (frompci >= p->textsize) 167 goto done; 168 169 frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))]; 170 toindex = *frompcindex; 171 if (toindex == 0) { 172 /* 173 * first time traversing this arc 174 */ 175 toindex = ++p->tos[0].link; 176 if (toindex >= p->tolimit) 177 /* halt further profiling */ 178 goto overflow; 179 180 *frompcindex = toindex; 181 top = &p->tos[toindex]; 182 top->selfpc = selfpc; 183 top->count = 1; 184 top->link = 0; 185 goto done; 186 } 187 top = &p->tos[toindex]; 188 if (top->selfpc == selfpc) { 189 /* 190 * arc at front of chain; usual case. 191 */ 192 top->count++; 193 goto done; 194 } 195 /* 196 * have to go looking down chain for it. 197 * top points to what we are looking at, 198 * prevtop points to previous top. 199 * we know it is not at the head of the chain. 200 */ 201 for (; /* goto done */; ) { 202 if (top->link == 0) { 203 /* 204 * top is end of the chain and none of the chain 205 * had top->selfpc == selfpc. 206 * so we allocate a new tostruct 207 * and link it to the head of the chain. 208 */ 209 toindex = ++p->tos[0].link; 210 if (toindex >= p->tolimit) 211 goto overflow; 212 213 top = &p->tos[toindex]; 214 top->selfpc = selfpc; 215 top->count = 1; 216 top->link = *frompcindex; 217 *frompcindex = toindex; 218 goto done; 219 } 220 /* 221 * otherwise, check the next arc on the chain. 222 */ 223 prevtop = top; 224 top = &p->tos[top->link]; 225 if (top->selfpc == selfpc) { 226 /* 227 * there it is. 228 * increment its count 229 * move it to the head of the chain. 230 */ 231 top->count++; 232 toindex = prevtop->link; 233 prevtop->link = top->link; 234 top->link = *frompcindex; 235 *frompcindex = toindex; 236 goto done; 237 } 238 239 } 240done:
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241#ifdef KERNEL
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241#ifdef _KERNEL |
242 MCOUNT_EXIT(s); 243#else 244 p->state = GMON_PROF_ON; 245#endif 246 return; 247overflow: 248 p->state = GMON_PROF_ERROR;
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249#ifdef KERNEL
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249#ifdef _KERNEL |
250 MCOUNT_EXIT(s); 251#endif 252 return; 253} 254 255/* 256 * Actual definition of mcount function. Defined in <machine/profile.h>, 257 * which is included by <sys/gmon.h>. 258 */ 259MCOUNT 260 261#ifdef GUPROF 262void 263mexitcount(selfpc) 264 uintfptr_t selfpc; 265{ 266 struct gmonparam *p; 267 uintfptr_t selfpcdiff; 268 269 p = &_gmonparam; 270 selfpcdiff = selfpc - (uintfptr_t)p->lowpc; 271 if (selfpcdiff < p->textsize) { 272 int delta; 273 274 /* 275 * Count the time since cputime() was previously called 276 * against `selfpc'. Compensate for overheads. 277 */ 278 delta = cputime() - cputime_bias - p->mexitcount_pre_overhead; 279 cputime_bias = p->mexitcount_post_overhead; 280 KCOUNT(p, selfpcdiff) += delta; 281 *p->cputime_count += p->cputime_overhead; 282 *p->mexitcount_count += p->mexitcount_overhead; 283 } 284} 285 286void 287empty_loop() 288{ 289 int i; 290 291 for (i = 0; i < CALIB_SCALE; i++) 292 ; 293} 294 295void 296nullfunc() 297{ 298} 299 300void 301nullfunc_loop() 302{ 303 int i; 304 305 for (i = 0; i < CALIB_SCALE; i++) 306 nullfunc(); 307} 308#endif /* GUPROF */
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