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 * 33 * @(#)mcount.c 8.1 (Berkeley) 6/4/93 34 * $FreeBSD: src/lib/libc/gmon/mcount.c,v 1.17 1999/12/29 05:04:13 peter Exp $ 35 * $DragonFly: src/lib/libc/gmon/mcount.c,v 1.5 2005/11/13 01:18:20 swildner Exp $ 36 */ 37 38 #include <sys/param.h> 39 #include <sys/gmon.h> 40 #ifdef _KERNEL 41 #include <sys/systm.h> 42 #include <vm/vm.h> 43 #include <vm/vm_param.h> 44 #include <vm/pmap.h> 45 void bintr (void); 46 void btrap (void); 47 void eintr (void); 48 void user (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; may be static, inline, etc 67 */ 68 _MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc) 69 { 70 #ifdef GUPROF 71 u_int delta; 72 #endif 73 fptrdiff_t frompci; 74 u_short *frompcindex; 75 struct tostruct *top, *prevtop; 76 struct gmonparam *p; 77 long toindex; 78 #ifdef _KERNEL 79 MCOUNT_DECL(s) 80 #endif 81 82 p = &_gmonparam; 83 #ifndef GUPROF /* XXX */ 84 /* 85 * check that we are profiling 86 * and that we aren't recursively invoked. 87 */ 88 if (p->state != GMON_PROF_ON) 89 return; 90 #endif 91 #ifdef _KERNEL 92 MCOUNT_ENTER(s); 93 #else 94 p->state = GMON_PROF_BUSY; 95 #endif 96 frompci = frompc - p->lowpc; 97 98 #ifdef _KERNEL 99 /* 100 * When we are called from an exception handler, frompci may be 101 * for a user address. Convert such frompci's to the index of 102 * user() to merge all user counts. 103 */ 104 if (frompci >= p->textsize) { 105 if (frompci + p->lowpc 106 >= (uintfptr_t)(VM_MAXUSER_ADDRESS + UPAGES * PAGE_SIZE)) 107 goto done; 108 frompci = (uintfptr_t)user - p->lowpc; 109 if (frompci >= p->textsize) 110 goto done; 111 } 112 #endif 113 114 #ifdef GUPROF 115 if (p->state != GMON_PROF_HIRES) 116 goto skip_guprof_stuff; 117 /* 118 * Look at the clock and add the count of clock cycles since the 119 * clock was last looked at to a counter for frompc. This 120 * solidifies the count for the function containing frompc and 121 * effectively starts another clock for the current function. 122 * The count for the new clock will be solidified when another 123 * function call is made or the function returns. 124 * 125 * We use the usual sampling counters since they can be located 126 * efficiently. 4-byte counters are usually necessary. 127 * 128 * There are many complications for subtracting the profiling 129 * overheads from the counts for normal functions and adding 130 * them to the counts for mcount(), mexitcount() and cputime(). 131 * We attempt to handle fractional cycles, but the overheads 132 * are usually underestimated because they are calibrated for 133 * a simpler than usual setup. 134 */ 135 delta = cputime() - p->mcount_overhead; 136 p->cputime_overhead_resid += p->cputime_overhead_frac; 137 p->mcount_overhead_resid += p->mcount_overhead_frac; 138 if ((int)delta < 0) 139 *p->mcount_count += delta + p->mcount_overhead 140 - p->cputime_overhead; 141 else if (delta != 0) { 142 if (p->cputime_overhead_resid >= CALIB_SCALE) { 143 p->cputime_overhead_resid -= CALIB_SCALE; 144 ++*p->cputime_count; 145 --delta; 146 } 147 if (delta != 0) { 148 if (p->mcount_overhead_resid >= CALIB_SCALE) { 149 p->mcount_overhead_resid -= CALIB_SCALE; 150 ++*p->mcount_count; 151 --delta; 152 } 153 KCOUNT(p, frompci) += delta; 154 } 155 *p->mcount_count += p->mcount_overhead_sub; 156 } 157 *p->cputime_count += p->cputime_overhead; 158 skip_guprof_stuff: 159 #endif /* GUPROF */ 160 161 #ifdef _KERNEL 162 /* 163 * When we are called from an exception handler, frompc is faked 164 * to be for where the exception occurred. We've just solidified 165 * the count for there. Now convert frompci to the index of btrap() 166 * for trap handlers and bintr() for interrupt handlers to make 167 * exceptions appear in the call graph as calls from btrap() and 168 * bintr() instead of calls from all over. 169 */ 170 if ((uintfptr_t)selfpc >= (uintfptr_t)btrap 171 && (uintfptr_t)selfpc < (uintfptr_t)eintr) { 172 if ((uintfptr_t)selfpc >= (uintfptr_t)bintr) 173 frompci = (uintfptr_t)bintr - p->lowpc; 174 else 175 frompci = (uintfptr_t)btrap - p->lowpc; 176 } 177 #endif 178 179 /* 180 * check that frompc is a reasonable pc value. 181 * for example: signal catchers get called from the stack, 182 * not from text space. too bad. 183 */ 184 if (frompci >= p->textsize) 185 goto done; 186 187 frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))]; 188 toindex = *frompcindex; 189 if (toindex == 0) { 190 /* 191 * first time traversing this arc 192 */ 193 toindex = ++p->tos[0].link; 194 if (toindex >= p->tolimit) 195 /* halt further profiling */ 196 goto overflow; 197 198 *frompcindex = toindex; 199 top = &p->tos[toindex]; 200 top->selfpc = selfpc; 201 top->count = 1; 202 top->link = 0; 203 goto done; 204 } 205 top = &p->tos[toindex]; 206 if (top->selfpc == selfpc) { 207 /* 208 * arc at front of chain; usual case. 209 */ 210 top->count++; 211 goto done; 212 } 213 /* 214 * have to go looking down chain for it. 215 * top points to what we are looking at, 216 * prevtop points to previous top. 217 * we know it is not at the head of the chain. 218 */ 219 for (; /* goto done */; ) { 220 if (top->link == 0) { 221 /* 222 * top is end of the chain and none of the chain 223 * had top->selfpc == selfpc. 224 * so we allocate a new tostruct 225 * and link it to the head of the chain. 226 */ 227 toindex = ++p->tos[0].link; 228 if (toindex >= p->tolimit) 229 goto overflow; 230 231 top = &p->tos[toindex]; 232 top->selfpc = selfpc; 233 top->count = 1; 234 top->link = *frompcindex; 235 *frompcindex = toindex; 236 goto done; 237 } 238 /* 239 * otherwise, check the next arc on the chain. 240 */ 241 prevtop = top; 242 top = &p->tos[top->link]; 243 if (top->selfpc == selfpc) { 244 /* 245 * there it is. 246 * increment its count 247 * move it to the head of the chain. 248 */ 249 top->count++; 250 toindex = prevtop->link; 251 prevtop->link = top->link; 252 top->link = *frompcindex; 253 *frompcindex = toindex; 254 goto done; 255 } 256 257 } 258 done: 259 #ifdef _KERNEL 260 MCOUNT_EXIT(s); 261 #else 262 p->state = GMON_PROF_ON; 263 #endif 264 return; 265 overflow: 266 p->state = GMON_PROF_ERROR; 267 #ifdef _KERNEL 268 MCOUNT_EXIT(s); 269 #endif 270 return; 271 } 272 273 /* 274 * Actual definition of mcount function. Defined in <machine/profile.h>, 275 * which is included by <sys/gmon.h>. 276 */ 277 MCOUNT 278 279 #ifdef GUPROF 280 void 281 mexitcount(uintfptr_t selfpc) 282 { 283 struct gmonparam *p; 284 uintfptr_t selfpcdiff; 285 286 p = &_gmonparam; 287 selfpcdiff = selfpc - (uintfptr_t)p->lowpc; 288 if (selfpcdiff < p->textsize) { 289 u_int delta; 290 291 /* 292 * Solidify the count for the current function. 293 */ 294 delta = cputime() - p->mexitcount_overhead; 295 p->cputime_overhead_resid += p->cputime_overhead_frac; 296 p->mexitcount_overhead_resid += p->mexitcount_overhead_frac; 297 if ((int)delta < 0) 298 *p->mexitcount_count += delta + p->mexitcount_overhead 299 - p->cputime_overhead; 300 else if (delta != 0) { 301 if (p->cputime_overhead_resid >= CALIB_SCALE) { 302 p->cputime_overhead_resid -= CALIB_SCALE; 303 ++*p->cputime_count; 304 --delta; 305 } 306 if (delta != 0) { 307 if (p->mexitcount_overhead_resid 308 >= CALIB_SCALE) { 309 p->mexitcount_overhead_resid 310 -= CALIB_SCALE; 311 ++*p->mexitcount_count; 312 --delta; 313 } 314 KCOUNT(p, selfpcdiff) += delta; 315 } 316 *p->mexitcount_count += p->mexitcount_overhead_sub; 317 } 318 *p->cputime_count += p->cputime_overhead; 319 } 320 } 321 #endif /* GUPROF */ 322