1 /* $NetBSD: subr_prof.c,v 1.47 2014/07/10 21:13:52 christos 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 1.47 2014/07/10 21:13:52 christos 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/mount.h> 42 #include <sys/syscallargs.h> 43 #include <sys/sysctl.h> 44 45 #include <sys/cpu.h> 46 47 #ifdef GPROF 48 #include <sys/malloc.h> 49 #include <sys/gmon.h> 50 51 MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer"); 52 53 /* 54 * Froms is actually a bunch of unsigned shorts indexing tos 55 */ 56 struct gmonparam _gmonparam = { .state = GMON_PROF_OFF }; 57 58 /* Actual start of the kernel text segment. */ 59 extern char kernel_text[]; 60 61 extern char etext[]; 62 63 64 void 65 kmstartup(void) 66 { 67 char *cp; 68 struct gmonparam *p = &_gmonparam; 69 /* 70 * Round lowpc and highpc to multiples of the density we're using 71 * so the rest of the scaling (here and in gprof) stays in ints. 72 */ 73 p->lowpc = rounddown(((u_long)kernel_text), 74 HISTFRACTION * sizeof(HISTCOUNTER)); 75 p->highpc = roundup((u_long)etext, 76 HISTFRACTION * sizeof(HISTCOUNTER)); 77 p->textsize = p->highpc - p->lowpc; 78 printf("Profiling kernel, textsize=%ld [%lx..%lx]\n", 79 p->textsize, p->lowpc, p->highpc); 80 p->kcountsize = p->textsize / HISTFRACTION; 81 p->hashfraction = HASHFRACTION; 82 p->fromssize = p->textsize / HASHFRACTION; 83 p->tolimit = p->textsize * ARCDENSITY / 100; 84 if (p->tolimit < MINARCS) 85 p->tolimit = MINARCS; 86 else if (p->tolimit > MAXARCS) 87 p->tolimit = MAXARCS; 88 p->tossize = p->tolimit * sizeof(struct tostruct); 89 cp = malloc(p->kcountsize + p->fromssize + p->tossize, 90 M_GPROF, M_NOWAIT | M_ZERO); 91 if (cp == 0) { 92 printf("No memory for profiling.\n"); 93 return; 94 } 95 p->tos = (struct tostruct *)cp; 96 cp += p->tossize; 97 p->kcount = (u_short *)cp; 98 cp += p->kcountsize; 99 p->froms = (u_short *)cp; 100 } 101 102 /* 103 * Return kernel profiling information. 104 */ 105 /* 106 * sysctl helper routine for kern.profiling subtree. enables/disables 107 * kernel profiling and gives out copies of the profiling data. 108 */ 109 static int 110 sysctl_kern_profiling(SYSCTLFN_ARGS) 111 { 112 struct gmonparam *gp = &_gmonparam; 113 int error; 114 struct sysctlnode node; 115 116 node = *rnode; 117 118 switch (node.sysctl_num) { 119 case GPROF_STATE: 120 node.sysctl_data = &gp->state; 121 break; 122 case GPROF_COUNT: 123 node.sysctl_data = gp->kcount; 124 node.sysctl_size = gp->kcountsize; 125 break; 126 case GPROF_FROMS: 127 node.sysctl_data = gp->froms; 128 node.sysctl_size = gp->fromssize; 129 break; 130 case GPROF_TOS: 131 node.sysctl_data = gp->tos; 132 node.sysctl_size = gp->tossize; 133 break; 134 case GPROF_GMONPARAM: 135 node.sysctl_data = gp; 136 node.sysctl_size = sizeof(*gp); 137 break; 138 default: 139 return (EOPNOTSUPP); 140 } 141 142 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 143 if (error || newp == NULL) 144 return (error); 145 146 if (node.sysctl_num == GPROF_STATE) { 147 mutex_spin_enter(&proc0.p_stmutex); 148 if (gp->state == GMON_PROF_OFF) 149 stopprofclock(&proc0); 150 else 151 startprofclock(&proc0); 152 mutex_spin_exit(&proc0.p_stmutex); 153 } 154 155 return (0); 156 } 157 158 SYSCTL_SETUP(sysctl_kern_gprof_setup, "sysctl kern.profiling subtree setup") 159 { 160 161 sysctl_createv(clog, 0, NULL, NULL, 162 CTLFLAG_PERMANENT, 163 CTLTYPE_NODE, "profiling", 164 SYSCTL_DESCR("Profiling information (available)"), 165 NULL, 0, NULL, 0, 166 CTL_KERN, KERN_PROF, CTL_EOL); 167 168 sysctl_createv(clog, 0, NULL, NULL, 169 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 170 CTLTYPE_INT, "state", 171 SYSCTL_DESCR("Profiling state"), 172 sysctl_kern_profiling, 0, NULL, 0, 173 CTL_KERN, KERN_PROF, GPROF_STATE, CTL_EOL); 174 sysctl_createv(clog, 0, NULL, NULL, 175 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 176 CTLTYPE_STRUCT, "count", 177 SYSCTL_DESCR("Array of statistical program counters"), 178 sysctl_kern_profiling, 0, NULL, 0, 179 CTL_KERN, KERN_PROF, GPROF_COUNT, CTL_EOL); 180 sysctl_createv(clog, 0, NULL, NULL, 181 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 182 CTLTYPE_STRUCT, "froms", 183 SYSCTL_DESCR("Array indexed by program counter of " 184 "call-from points"), 185 sysctl_kern_profiling, 0, NULL, 0, 186 CTL_KERN, KERN_PROF, GPROF_FROMS, CTL_EOL); 187 sysctl_createv(clog, 0, NULL, NULL, 188 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 189 CTLTYPE_STRUCT, "tos", 190 SYSCTL_DESCR("Array of structures describing " 191 "destination of calls and their counts"), 192 sysctl_kern_profiling, 0, NULL, 0, 193 CTL_KERN, KERN_PROF, GPROF_TOS, CTL_EOL); 194 sysctl_createv(clog, 0, NULL, NULL, 195 CTLFLAG_PERMANENT, 196 CTLTYPE_STRUCT, "gmonparam", 197 SYSCTL_DESCR("Structure giving the sizes of the above " 198 "arrays"), 199 sysctl_kern_profiling, 0, NULL, 0, 200 CTL_KERN, KERN_PROF, GPROF_GMONPARAM, CTL_EOL); 201 } 202 #endif /* GPROF */ 203 204 /* 205 * Profiling system call. 206 * 207 * The scale factor is a fixed point number with 16 bits of fraction, so that 208 * 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling. 209 */ 210 /* ARGSUSED */ 211 int 212 sys_profil(struct lwp *l, const struct sys_profil_args *uap, register_t *retval) 213 { 214 /* { 215 syscallarg(char *) samples; 216 syscallarg(size_t) size; 217 syscallarg(u_long) offset; 218 syscallarg(u_int) scale; 219 } */ 220 struct proc *p = l->l_proc; 221 struct uprof *upp; 222 223 if (SCARG(uap, scale) > (1 << 16)) 224 return (EINVAL); 225 if (SCARG(uap, scale) == 0) { 226 mutex_spin_enter(&p->p_stmutex); 227 stopprofclock(p); 228 mutex_spin_exit(&p->p_stmutex); 229 return (0); 230 } 231 upp = &p->p_stats->p_prof; 232 233 /* Block profile interrupts while changing state. */ 234 mutex_spin_enter(&p->p_stmutex); 235 upp->pr_off = SCARG(uap, offset); 236 upp->pr_scale = SCARG(uap, scale); 237 upp->pr_base = SCARG(uap, samples); 238 upp->pr_size = SCARG(uap, size); 239 startprofclock(p); 240 mutex_spin_exit(&p->p_stmutex); 241 242 return (0); 243 } 244 245 /* 246 * Scale is a fixed-point number with the binary point 16 bits 247 * into the value, and is <= 1.0. pc is at most 32 bits, so the 248 * intermediate result is at most 48 bits. 249 */ 250 #define PC_TO_INDEX(pc, prof) \ 251 ((int)(((u_quad_t)((pc) - (prof)->pr_off) * \ 252 (u_quad_t)((prof)->pr_scale)) >> 16) & ~1) 253 254 /* 255 * Collect user-level profiling statistics; called on a profiling tick, 256 * when a process is running in user-mode. This routine may be called 257 * from an interrupt context. We try to update the user profiling buffers 258 * cheaply with fuswintr() and suswintr(). If that fails, we revert to 259 * an AST that will vector us to trap() with a context in which copyin 260 * and copyout will work. Trap will then call addupc_task(). 261 * 262 * Note that we may (rarely) not get around to the AST soon enough, and 263 * lose profile ticks when the next tick overwrites this one, but in this 264 * case the system is overloaded and the profile is probably already 265 * inaccurate. 266 */ 267 void 268 addupc_intr(struct lwp *l, u_long pc) 269 { 270 struct uprof *prof; 271 struct proc *p; 272 void *addr; 273 u_int i; 274 int v; 275 276 p = l->l_proc; 277 278 KASSERT(mutex_owned(&p->p_stmutex)); 279 280 prof = &p->p_stats->p_prof; 281 if (pc < prof->pr_off || 282 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) 283 return; /* out of range; ignore */ 284 285 addr = prof->pr_base + i; 286 mutex_spin_exit(&p->p_stmutex); 287 if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + 1) == -1) { 288 /* XXXSMP */ 289 prof->pr_addr = pc; 290 prof->pr_ticks++; 291 cpu_need_proftick(l); 292 } 293 mutex_spin_enter(&p->p_stmutex); 294 } 295 296 /* 297 * Much like before, but we can afford to take faults here. If the 298 * update fails, we simply turn off profiling. 299 */ 300 void 301 addupc_task(struct lwp *l, u_long pc, u_int ticks) 302 { 303 struct uprof *prof; 304 struct proc *p; 305 void *addr; 306 int error; 307 u_int i; 308 u_short v; 309 310 p = l->l_proc; 311 312 if (ticks == 0) 313 return; 314 315 mutex_spin_enter(&p->p_stmutex); 316 prof = &p->p_stats->p_prof; 317 318 /* Testing P_PROFIL may be unnecessary, but is certainly safe. */ 319 if ((p->p_stflag & PST_PROFIL) == 0 || pc < prof->pr_off || 320 (i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) { 321 mutex_spin_exit(&p->p_stmutex); 322 return; 323 } 324 325 addr = prof->pr_base + i; 326 mutex_spin_exit(&p->p_stmutex); 327 if ((error = copyin(addr, (void *)&v, sizeof(v))) == 0) { 328 v += ticks; 329 error = copyout((void *)&v, addr, sizeof(v)); 330 } 331 if (error != 0) { 332 mutex_spin_enter(&p->p_stmutex); 333 stopprofclock(p); 334 mutex_spin_exit(&p->p_stmutex); 335 } 336 } 337