1 /* $NetBSD: subr_prof.c,v 1.43 2007/12/20 23:03:10 dsl Exp $ */ 2 3 /*- 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)subr_prof.c 8.4 (Berkeley) 2/14/95 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: subr_prof.c,v 1.43 2007/12/20 23:03:10 dsl Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/kernel.h> 40 #include <sys/proc.h> 41 #include <sys/user.h> 42 #include <sys/mount.h> 43 #include <sys/syscallargs.h> 44 #include <sys/sysctl.h> 45 46 #include <sys/cpu.h> 47 48 #ifdef GPROF 49 #include <sys/malloc.h> 50 #include <sys/gmon.h> 51 52 MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 53 54 /* 55 * Froms is actually a bunch of unsigned shorts indexing tos 56 */ 57 struct gmonparam _gmonparam = { .state = GMON_PROF_OFF }; 58 59 /* Actual start of the kernel text segment. */ 60 extern char kernel_text[]; 61 62 extern char etext[]; 63 64 65 void 66 kmstartup(void) 67 { 68 char *cp; 69 struct gmonparam *p = &_gmonparam; 70 /* 71 * Round lowpc and highpc to multiples of the density we're using 72 * so the rest of the scaling (here and in gprof) stays in ints. 73 */ 74 p->lowpc = rounddown(((u_long)kernel_text), 75 HISTFRACTION * sizeof(HISTCOUNTER)); 76 p->highpc = roundup((u_long)etext, 77 HISTFRACTION * sizeof(HISTCOUNTER)); 78 p->textsize = p->highpc - p->lowpc; 79 printf("Profiling kernel, textsize=%ld [%lx..%lx]\n", 80 p->textsize, p->lowpc, p->highpc); 81 p->kcountsize = p->textsize / HISTFRACTION; 82 p->hashfraction = HASHFRACTION; 83 p->fromssize = p->textsize / HASHFRACTION; 84 p->tolimit = p->textsize * ARCDENSITY / 100; 85 if (p->tolimit < MINARCS) 86 p->tolimit = MINARCS; 87 else if (p->tolimit > MAXARCS) 88 p->tolimit = MAXARCS; 89 p->tossize = p->tolimit * sizeof(struct tostruct); 90 cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize, 91 M_GPROF, M_NOWAIT | M_ZERO); 92 if (cp == 0) { 93 printf("No memory for profiling.\n"); 94 return; 95 } 96 p->tos = (struct tostruct *)cp; 97 cp += p->tossize; 98 p->kcount = (u_short *)cp; 99 cp += p->kcountsize; 100 p->froms = (u_short *)cp; 101 } 102 103 /* 104 * Return kernel profiling information. 105 */ 106 /* 107 * sysctl helper routine for kern.profiling subtree. enables/disables 108 * kernel profiling and gives out copies of the profiling data. 109 */ 110 static int 111 sysctl_kern_profiling(SYSCTLFN_ARGS) 112 { 113 struct gmonparam *gp = &_gmonparam; 114 int error; 115 struct sysctlnode node; 116 117 node = *rnode; 118 119 switch (node.sysctl_num) { 120 case GPROF_STATE: 121 node.sysctl_data = &gp->state; 122 break; 123 case GPROF_COUNT: 124 node.sysctl_data = gp->kcount; 125 node.sysctl_size = gp->kcountsize; 126 break; 127 case GPROF_FROMS: 128 node.sysctl_data = gp->froms; 129 node.sysctl_size = gp->fromssize; 130 break; 131 case GPROF_TOS: 132 node.sysctl_data = gp->tos; 133 node.sysctl_size = gp->tossize; 134 break; 135 case GPROF_GMONPARAM: 136 node.sysctl_data = gp; 137 node.sysctl_size = sizeof(*gp); 138 break; 139 default: 140 return (EOPNOTSUPP); 141 } 142 143 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 144 if (error || newp == NULL) 145 return (error); 146 147 if (node.sysctl_num == GPROF_STATE) { 148 mutex_spin_enter(&proc0.p_stmutex); 149 if (gp->state == GMON_PROF_OFF) 150 stopprofclock(&proc0); 151 else 152 startprofclock(&proc0); 153 mutex_spin_exit(&proc0.p_stmutex); 154 } 155 156 return (0); 157 } 158 159 SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup") 160 { 161 162 sysctl_createv(clog, 0, NULL, NULL, 163 CTLFLAG_PERMANENT, 164 CTLTYPE_NODE, "kern", NULL, 165 NULL, 0, NULL, 0, 166 CTL_KERN, CTL_EOL); 167 sysctl_createv(clog, 0, NULL, NULL, 168 CTLFLAG_PERMANENT, 169 CTLTYPE_NODE, "profiling", 170 SYSCTL_DESCR("Profiling information (available)"), 171 NULL, 0, NULL, 0, 172 CTL_KERN, KERN_PROF, CTL_EOL); 173 174 sysctl_createv(clog, 0, NULL, NULL, 175 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 176 CTLTYPE_INT, "state", 177 SYSCTL_DESCR("Profiling state"), 178 sysctl_kern_profiling, 0, NULL, 0, 179 CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL); 180 sysctl_createv(clog, 0, NULL, NULL, 181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 182 CTLTYPE_STRUCT, "count", 183 SYSCTL_DESCR("Array of statistical program counters"), 184 sysctl_kern_profiling, 0, NULL, 0, 185 CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL); 186 sysctl_createv(clog, 0, NULL, NULL, 187 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 188 CTLTYPE_STRUCT, "froms", 189 SYSCTL_DESCR("Array indexed by program counter of " 190 "call-from points"), 191 sysctl_kern_profiling, 0, NULL, 0, 192 CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL); 193 sysctl_createv(clog, 0, NULL, NULL, 194 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 195 CTLTYPE_STRUCT, "tos", 196 SYSCTL_DESCR("Array of structures describing " 197 "destination of calls and their counts"), 198 sysctl_kern_profiling, 0, NULL, 0, 199 CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL); 200 sysctl_createv(clog, 0, NULL, NULL, 201 CTLFLAG_PERMANENT, 202 CTLTYPE_STRUCT, "gmonparam", 203 SYSCTL_DESCR("Structure giving the sizes of the above " 204 "arrays"), 205 sysctl_kern_profiling, 0, NULL, 0, 206 CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL); 207 } 208 #endif /* GPROF */ 209 210 /* 211 * Profiling system call. 212 * 213 * The scale factor is a fixed point number with 16 bits of fraction, so that 214 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 215 */ 216 /* ARGSUSED */ 217 int 218 sys_profil(struct lwp *l, const struct sys_profil_args *uap, register_t *retval) 219 { 220 /* { 221 syscallarg(char *) samples; 222 syscallarg(u_int) size; 223 syscallarg(u_int) offset; 224 syscallarg(u_int) scale; 225 } */ 226 struct proc *p = l->l_proc; 227 struct uprof *upp; 228 229 if (SCARG(uap, scale) > (1 << 16)) 230 return (EINVAL); 231 if (SCARG(uap, scale) == 0) { 232 mutex_spin_enter(&p->p_stmutex); 233 stopprofclock(p); 234 mutex_spin_exit(&p->p_stmutex); 235 return (0); 236 } 237 upp = &p->p_stats->p_prof; 238 239 /* Block profile interrupts while changing state. */ 240 mutex_spin_enter(&p->p_stmutex); 241 upp->pr_off = SCARG(uap, offset); 242 upp->pr_scale = SCARG(uap, scale); 243 upp->pr_base = SCARG(uap, samples); 244 upp->pr_size = SCARG(uap, size); 245 startprofclock(p); 246 mutex_spin_exit(&p->p_stmutex); 247 248 return (0); 249 } 250 251 /* 252 * Scale is a fixed-point number with the binary point 16 bits 253 * into the value, and is <= 1.0. pc is at most 32 bits, so the 254 * intermediate result is at most 48 bits. 255 */ 256 #define PC_TO_INDEX(pc, prof) \ 257 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 258 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 259 260 /* 261 * Collect user-level profiling statistics; called on a profiling tick, 262 * when a process is running in user-mode. This routine may be called 263 * from an interrupt context. We try to update the user profiling buffers 264 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 265 * an AST that will vector us to trap() with a context in which copyin 266 * and copyout will work. Trap will then call addupc_task(). 267 * 268 * Note that we may (rarely) not get around to the AST soon enough, and 269 * lose profile ticks when the next tick overwrites this one, but in this 270 * case the system is overloaded and the profile is probably already 271 * inaccurate. 272 */ 273 void 274 addupc_intr(struct lwp *l, u_long pc) 275 { 276 struct uprof *prof; 277 struct proc *p; 278 void *addr; 279 u_int i; 280 int v; 281 282 p = l->l_proc; 283 284 KASSERT(mutex_owned(&p->p_stmutex)); 285 286 prof = &p->p_stats->p_prof; 287 if (pc < prof->pr_off || 288 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 289 return; /* out of range; ignore */ 290 291 addr = prof->pr_base + i; 292 mutex_spin_exit(&p->p_stmutex); 293 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) { 294 /* XXXSMP */ 295 prof->pr_addr = pc; 296 prof->pr_ticks++; 297 cpu_need_proftick(l); 298 } 299 mutex_spin_enter(&p->p_stmutex); 300 } 301 302 /* 303 * Much like before, but we can afford to take faults here. If the 304 * update fails, we simply turn off profiling. 305 */ 306 void 307 addupc_task(struct lwp *l, u_long pc, u_int ticks) 308 { 309 struct uprof *prof; 310 struct proc *p; 311 void *addr; 312 int error; 313 u_int i; 314 u_short v; 315 316 p = l->l_proc; 317 318 if (ticks == 0) 319 return; 320 321 mutex_spin_enter(&p->p_stmutex); 322 prof = &p->p_stats->p_prof; 323 324 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 325 if ((p->p_stflag & PST_PROFIL) == 0 || pc < prof->pr_off || 326 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 327 mutex_spin_exit(&p->p_stmutex); 328 return; 329 } 330 331 addr = prof->pr_base + i; 332 mutex_spin_exit(&p->p_stmutex); 333 if ((error = copyin(addr, (void *)&v, sizeof(v))) == 0) { 334 v += ticks; 335 error = copyout((void *)&v, addr, sizeof(v)); 336 } 337 if (error != 0) { 338 mutex_spin_enter(&p->p_stmutex); 339 stopprofclock(p); 340 mutex_spin_exit(&p->p_stmutex); 341 } 342 } 343