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 1.20 2004/10/16 06:32:43 obrien 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 _MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc) 68 { 69 #ifdef GUPROF 70 u_int delta; 71 #endif 72 fptrdiff_t frompci; 73 u_short *frompcindex; 74 struct tostruct *top, *prevtop; 75 struct gmonparam *p; 76 long toindex; 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 90 #ifdef _KERNEL 91 MCOUNT_ENTER(s); 92 #else 93 p->state = GMON_PROF_BUSY; /* XXX */ 94 #endif 95 frompci = frompc - p->lowpc; 96 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 } 111 #endif 112 113 #ifdef GUPROF 114 if (p->state != GMON_PROF_HIRES) 115 goto skip_guprof_stuff; 116 /* 117 * Look at the clock and add the count of clock cycles since the 118 * clock was last looked at to a counter for frompc. This 119 * solidifies the count for the function containing frompc and 120 * effectively starts another clock for the current function. 121 * The count for the new clock will be solidified when another 122 * function call is made or the function returns. 123 * 124 * We use the usual sampling counters since they can be located 125 * efficiently. 4-byte counters are usually necessary. 126 * 127 * There are many complications for subtracting the profiling 128 * overheads from the counts for normal functions and adding 129 * them to the counts for mcount(), mexitcount() and cputime(). 130 * We attempt to handle fractional cycles, but the overheads 131 * are usually underestimated because they are calibrated for 132 * a simpler than usual setup. 133 */ 134 delta = cputime() - p->mcount_overhead; 135 p->cputime_overhead_resid += p->cputime_overhead_frac; 136 p->mcount_overhead_resid += p->mcount_overhead_frac; 137 if ((int)delta < 0) 138 *p->mcount_count += delta + p->mcount_overhead 139 - p->cputime_overhead; 140 else if (delta != 0) { 141 if (p->cputime_overhead_resid >= CALIB_SCALE) { 142 p->cputime_overhead_resid -= CALIB_SCALE; 143 ++*p->cputime_count; 144 --delta; 145 } 146 if (delta != 0) { 147 if (p->mcount_overhead_resid >= CALIB_SCALE) { 148 p->mcount_overhead_resid -= CALIB_SCALE; 149 ++*p->mcount_count; 150 --delta; 151 } 152 KCOUNT(p, frompci) += delta; 153 } 154 *p->mcount_count += p->mcount_overhead_sub; 155 } 156 *p->cputime_count += p->cputime_overhead; 157 skip_guprof_stuff: 158 #endif /* GUPROF */ 159 160 #ifdef _KERNEL 161 /* 162 * When we are called from an exception handler, frompc is faked 163 * to be for where the exception occurred. We've just solidified 164 * the count for there. Now convert frompci to the index of btrap() 165 * for trap handlers and bintr() for interrupt handlers to make 166 * exceptions appear in the call graph as calls from btrap() and 167 * bintr() instead of calls from all over. 168 */ 169 if ((uintfptr_t)selfpc >= (uintfptr_t)btrap 170 && (uintfptr_t)selfpc < (uintfptr_t)eintr) { 171 if ((uintfptr_t)selfpc >= (uintfptr_t)bintr) 172 frompci = (uintfptr_t)bintr - p->lowpc; 173 else 174 frompci = (uintfptr_t)btrap - p->lowpc; 175 } 176 #endif 177 178 /* 179 * check that frompc is a reasonable pc value. 180 * for example: signal catchers get called from the stack, 181 * not from text space. too bad. 182 */ 183 if (frompci >= p->textsize) 184 goto done; 185 186 frompcindex = &p->froms[frompci / (p->hashfraction * sizeof(*p->froms))]; 187 toindex = *frompcindex; 188 if (toindex == 0) { 189 /* 190 * first time traversing this arc 191 */ 192 toindex = ++p->tos[0].link; 193 if (toindex >= p->tolimit) 194 /* halt further profiling */ 195 goto overflow; 196 197 *frompcindex = toindex; 198 top = &p->tos[toindex]; 199 top->selfpc = selfpc; 200 top->count = 1; 201 top->link = 0; 202 goto done; 203 } 204 top = &p->tos[toindex]; 205 if (top->selfpc == selfpc) { 206 /* 207 * arc at front of chain; usual case. 208 */ 209 top->count++; 210 goto done; 211 } 212 /* 213 * have to go looking down chain for it. 214 * top points to what we are looking at, 215 * prevtop points to previous top. 216 * we know it is not at the head of the chain. 217 */ 218 for (; /* goto done */; ) { 219 if (top->link == 0) { 220 /* 221 * top is end of the chain and none of the chain 222 * had top->selfpc == selfpc. 223 * so we allocate a new tostruct 224 * and link it to the head of the chain. 225 */ 226 toindex = ++p->tos[0].link; 227 if (toindex >= p->tolimit) 228 goto overflow; 229 230 top = &p->tos[toindex]; 231 top->selfpc = selfpc; 232 top->count = 1; 233 top->link = *frompcindex; 234 *frompcindex = toindex; 235 goto done; 236 } 237 /* 238 * otherwise, check the next arc on the chain. 239 */ 240 prevtop = top; 241 top = &p->tos[top->link]; 242 if (top->selfpc == selfpc) { 243 /* 244 * there it is. 245 * increment its count 246 * move it to the head of the chain. 247 */ 248 top->count++; 249 toindex = prevtop->link; 250 prevtop->link = top->link; 251 top->link = *frompcindex; 252 *frompcindex = toindex; 253 goto done; 254 } 255 256 } 257 done: 258 #ifdef _KERNEL 259 MCOUNT_EXIT(s); 260 #else 261 p->state = GMON_PROF_ON; /* XXX */ 262 #endif 263 return; 264 overflow: 265 p->state = GMON_PROF_ERROR; /* XXX */ 266 #ifdef _KERNEL 267 MCOUNT_EXIT(s); 268 #endif 269 return; 270 } 271 272 /* 273 * Actual definition of mcount function. Defined in <machine/profile.h>, 274 * which is included by <sys/gmon.h>. 275 */ 276 MCOUNT 277 278 #ifdef GUPROF 279 void 280 mexitcount(uintfptr_t selfpc) 281 { 282 struct gmonparam *p; 283 uintfptr_t selfpcdiff; 284 285 p = &_gmonparam; 286 selfpcdiff = selfpc - (uintfptr_t)p->lowpc; 287 if (selfpcdiff < p->textsize) { 288 u_int delta; 289 290 /* 291 * Solidify the count for the current function. 292 */ 293 delta = cputime() - p->mexitcount_overhead; 294 p->cputime_overhead_resid += p->cputime_overhead_frac; 295 p->mexitcount_overhead_resid += p->mexitcount_overhead_frac; 296 if ((int)delta < 0) 297 *p->mexitcount_count += delta + p->mexitcount_overhead 298 - p->cputime_overhead; 299 else if (delta != 0) { 300 if (p->cputime_overhead_resid >= CALIB_SCALE) { 301 p->cputime_overhead_resid -= CALIB_SCALE; 302 ++*p->cputime_count; 303 --delta; 304 } 305 if (delta != 0) { 306 if (p->mexitcount_overhead_resid 307 >= CALIB_SCALE) { 308 p->mexitcount_overhead_resid 309 -= CALIB_SCALE; 310 ++*p->mexitcount_count; 311 --delta; 312 } 313 KCOUNT(p, selfpcdiff) += delta; 314 } 315 *p->mexitcount_count += p->mexitcount_overhead_sub; 316 } 317 *p->cputime_count += p->cputime_overhead; 318 } 319 } 320 #endif /* GUPROF */ 321