sys/cddl/dev/dtrace/dtrace_debug.c

   1 /*-
   2  * Copyright (C) 2008 John Birrell <jb@freebsd.org>.
   3  * 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(s), this list of conditions and the following disclaimer as
  10  *    the first lines of this file unmodified other than the possible
  11  *    addition of one or more copyright notices.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice(s), this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
  17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  * DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  26  * DAMAGE.
  27  *
  28  * $FreeBSD$
  29  *
  30  */
  31
  32 #ifdef DEBUG
  33
  34 #if defined(__amd64__)
  35 static __inline int
  36 dtrace_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
  37 {
  38         u_char res;
  39
  40         __asm __volatile(
  41         "        lock ;                 "
  42         "       cmpxchgq %2,%1 ;        "
  43         "       sete    %0 ;            "
  44         "1:                             "
  45         "# dtrace_cmpset_long"
  46         : "=a" (res),                   /* 0 */
  47           "=m" (*dst)                   /* 1 */
  48         : "r" (src),                    /* 2 */
  49           "a" (exp),                    /* 3 */
  50           "m" (*dst)                    /* 4 */
  51         : "memory");
  52
  53         return (res);
  54 }
  55 #elif defined(__i386__)
  56 static __inline int
  57 dtrace_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
  58 {
  59         u_char res;
  60
  61         __asm __volatile(
  62         "        lock ;                 "
  63         "       cmpxchgl %2,%1 ;        "
  64         "       sete    %0 ;            "
  65         "1:                             "
  66         "# dtrace_cmpset_long"
  67         : "=a" (res),                   /* 0 */
  68           "=m" (*dst)                   /* 1 */
  69         : "r" (src),                    /* 2 */
  70           "a" (exp),                    /* 3 */
  71           "m" (*dst)                    /* 4 */
  72         : "memory");
  73
  74         return (res);
  75 }
  76 #endif
  77
  78 #define DTRACE_DEBUG_BUFR_SIZE  (32 * 1024)
  79
  80 struct dtrace_debug_data {
  81         char bufr[DTRACE_DEBUG_BUFR_SIZE];
  82         char *first;
  83         char *last;
  84         char *next;
  85 } dtrace_debug_data[MAXCPU];
  86
  87 static char dtrace_debug_bufr[DTRACE_DEBUG_BUFR_SIZE];
  88
  89 static volatile u_long  dtrace_debug_flag[MAXCPU];
  90
  91 static void
  92 dtrace_debug_lock(int cpu)
  93 {
  94         while (dtrace_cmpset_long(&dtrace_debug_flag[cpu], 0, 1) == 0)
  95                 /* Loop until the lock is obtained. */
  96                 ;
  97 }
  98
  99 static void
 100 dtrace_debug_unlock(int cpu)
 101 {
 102         dtrace_debug_flag[cpu] = 0;
 103 }
 104
 105 static void
 106 dtrace_debug_init(void *dummy)
 107 {
 108         int i;
 109         struct dtrace_debug_data *d;
 110
 111         for (i = 0; i <= mp_maxid; i++) {
 112                 if (pcpu_find(i) == NULL)
 113                         continue;
 114
 115                 d = &dtrace_debug_data[i];
 116
 117                 if (d->first == NULL) {
 118                         d->first = d->bufr;
 119                         d->next = d->bufr;
 120                         d->last = d->bufr + DTRACE_DEBUG_BUFR_SIZE - 1;
 121                         *(d->last) = '\0';
 122                 }
 123         }
 124 }
 125
 126 SYSINIT(dtrace_debug_init, SI_SUB_KDTRACE, SI_ORDER_ANY, dtrace_debug_init, NULL);
 127 SYSINIT(dtrace_debug_smpinit, SI_SUB_SMP, SI_ORDER_ANY, dtrace_debug_init, NULL);
 128
 129 static void
 130 dtrace_debug_output(void)
 131 {
 132         char *p;
 133         int i;
 134         struct dtrace_debug_data *d;
 135         uintptr_t count;
 136
 137         for (i = 0; i <= mp_maxid; i++) {
 138                 if (pcpu_find(i) == NULL)
 139                         continue;
 140
 141                 dtrace_debug_lock(i);
 142
 143                 d = &dtrace_debug_data[i];
 144
 145                 count = 0;
 146
 147                 if (d->first < d->next) {
 148                         char *p1 = dtrace_debug_bufr;
 149
 150                         count = (uintptr_t) d->next - (uintptr_t) d->first;
 151
 152                         for (p = d->first; p < d->next; p++)
 153                                 *p1++ = *p;
 154                 } else if (d->next > d->first) {
 155                         char *p1 = dtrace_debug_bufr;
 156
 157                         count = (uintptr_t) d->last - (uintptr_t) d->first;
 158
 159                         for (p = d->first; p < d->last; p++)
 160                                 *p1++ = *p;
 161
 162                         count += (uintptr_t) d->next - (uintptr_t) d->bufr;
 163
 164                         for (p = d->bufr; p < d->next; p++)
 165                                 *p1++ = *p;
 166                 }
 167
 168                 d->first = d->bufr;
 169                 d->next = d->bufr;
 170
 171                 dtrace_debug_unlock(i);
 172
 173                 if (count > 0) {
 174                         char *last = dtrace_debug_bufr + count;
 175
 176                         p = dtrace_debug_bufr;
 177
 178                         while (p < last) {
 179                                 if (*p == '\0') {
 180                                         p++;
 181                                         continue;
 182                                 }
 183
 184                                 printf("%s", p);
 185
 186                                 p += strlen(p);
 187                         }
 188                 }
 189         }
 190 }
 191
 192 /*
 193  * Functions below here are called from the probe context, so they can't call
 194  * _any_ functions outside the dtrace module without running foul of the function
 195  * boundary trace provider (fbt). The purpose of these functions is limited to
 196  * buffering debug strings for output when the probe completes on the current CPU.
 197  */
 198
 199 static __inline void
 200 dtrace_debug__putc(char c)
 201 {
 202         struct dtrace_debug_data *d = &dtrace_debug_data[curcpu];
 203
 204         *d->next++ = c;
 205
 206         if (d->next == d->last)
 207                 d->next = d->bufr;
 208
 209         *(d->next) = '\0';
 210
 211         if (d->next == d->first)
 212                 d->first++;
 213
 214         if (d->first == d->last)
 215                 d->first = d->bufr;
 216 }
 217
 218 static void __used
 219 dtrace_debug_putc(char c)
 220 {
 221         dtrace_debug_lock(curcpu);
 222
 223         dtrace_debug__putc(c);
 224
 225         dtrace_debug_unlock(curcpu);
 226 }
 227
 228 static void __used
 229 dtrace_debug_puts(const char *s)
 230 {
 231         dtrace_debug_lock(curcpu);
 232
 233         while (*s != '\0')
 234                 dtrace_debug__putc(*s++);
 235
 236         dtrace_debug__putc('\0');
 237
 238         dtrace_debug_unlock(curcpu);
 239 }
 240
 241 /*
 242  * Snaffled from sys/kern/subr_prf.c
 243  *
 244  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 245  * order; return an optional length and a pointer to the last character
 246  * written in the buffer (i.e., the first character of the string).
 247  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 248  */
 249 static char *
 250 dtrace_debug_ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
 251 {
 252         char *p, c;
 253
 254         p = nbuf;
 255         *p = '\0';
 256         do {
 257                 c = hex2ascii(num % base);
 258                 *++p = upper ? toupper(c) : c;
 259         } while (num /= base);
 260         if (lenp)
 261                 *lenp = p - nbuf;
 262         return (p);
 263 }
 264
 265 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1)
 266
 267 static void
 268 dtrace_debug_vprintf(const char *fmt, va_list ap)
 269 {
 270         char nbuf[MAXNBUF];
 271         const char *p, *percent, *q;
 272         u_char *up;
 273         int ch, n;
 274         uintmax_t num;
 275         int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
 276         int cflag, hflag, jflag, tflag, zflag;
 277         int dwidth, upper;
 278         int radix = 10;
 279         char padc;
 280         int stop = 0, retval = 0;
 281
 282         num = 0;
 283
 284         if (fmt == NULL)
 285                 fmt = "(fmt null)\n";
 286
 287         for (;;) {
 288                 padc = ' ';
 289                 width = 0;
 290                 while ((ch = (u_char)*fmt++) != '%' || stop) {
 291                         if (ch == '\0') {
 292                                 dtrace_debug__putc('\0');
 293                                 return;
 294                         }
 295                         dtrace_debug__putc(ch);
 296                 }
 297                 percent = fmt - 1;
 298                 qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
 299                 sign = 0; dot = 0; dwidth = 0; upper = 0;
 300                 cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
 301 reswitch:       switch (ch = (u_char)*fmt++) {
 302                 case '.':
 303                         dot = 1;
 304                         goto reswitch;
 305                 case '#':
 306                         sharpflag = 1;
 307                         goto reswitch;
 308                 case '+':
 309                         sign = 1;
 310                         goto reswitch;
 311                 case '-':
 312                         ladjust = 1;
 313                         goto reswitch;
 314                 case '%':
 315                         dtrace_debug__putc(ch);
 316                         break;
 317                 case '*':
 318                         if (!dot) {
 319                                 width = va_arg(ap, int);
 320                                 if (width < 0) {
 321                                         ladjust = !ladjust;
 322                                         width = -width;
 323                                 }
 324                         } else {
 325                                 dwidth = va_arg(ap, int);
 326                         }
 327                         goto reswitch;
 328                 case '0':
 329                         if (!dot) {
 330                                 padc = '0';
 331                                 goto reswitch;
 332                         }
 333                 case '1': case '2': case '3': case '4':
 334                 case '5': case '6': case '7': case '8': case '9':
 335                                 for (n = 0;; ++fmt) {
 336                                         n = n * 10 + ch - '0';
 337                                         ch = *fmt;
 338                                         if (ch < '0' || ch > '9')
 339                                                 break;
 340                                 }
 341                         if (dot)
 342                                 dwidth = n;
 343                         else
 344                                 width = n;
 345                         goto reswitch;
 346                 case 'b':
 347                         num = (u_int)va_arg(ap, int);
 348                         p = va_arg(ap, char *);
 349                         for (q = dtrace_debug_ksprintn(nbuf, num, *p++, NULL, 0); *q;)
 350                                 dtrace_debug__putc(*q--);
 351
 352                         if (num == 0)
 353                                 break;
 354
 355                         for (tmp = 0; *p;) {
 356                                 n = *p++;
 357                                 if (num & (1 << (n - 1))) {
 358                                         dtrace_debug__putc(tmp ? ',' : '<');
 359                                         for (; (n = *p) > ' '; ++p)
 360                                                 dtrace_debug__putc(n);
 361                                         tmp = 1;
 362                                 } else
 363                                         for (; *p > ' '; ++p)
 364                                                 continue;
 365                         }
 366                         if (tmp)
 367                                 dtrace_debug__putc('>');
 368                         break;
 369                 case 'c':
 370                         dtrace_debug__putc(va_arg(ap, int));
 371                         break;
 372                 case 'D':
 373                         up = va_arg(ap, u_char *);
 374                         p = va_arg(ap, char *);
 375                         if (!width)
 376                                 width = 16;
 377                         while(width--) {
 378                                 dtrace_debug__putc(hex2ascii(*up >> 4));
 379                                 dtrace_debug__putc(hex2ascii(*up & 0x0f));
 380                                 up++;
 381                                 if (width)
 382                                         for (q=p;*q;q++)
 383                                                 dtrace_debug__putc(*q);
 384                         }
 385                         break;
 386                 case 'd':
 387                 case 'i':
 388                         base = 10;
 389                         sign = 1;
 390                         goto handle_sign;
 391                 case 'h':
 392                         if (hflag) {
 393                                 hflag = 0;
 394                                 cflag = 1;
 395                         } else
 396                                 hflag = 1;
 397                         goto reswitch;
 398                 case 'j':
 399                         jflag = 1;
 400                         goto reswitch;
 401                 case 'l':
 402                         if (lflag) {
 403                                 lflag = 0;
 404                                 qflag = 1;
 405                         } else
 406                                 lflag = 1;
 407                         goto reswitch;
 408                 case 'n':
 409                         if (jflag)
 410                                 *(va_arg(ap, intmax_t *)) = retval;
 411                         else if (qflag)
 412                                 *(va_arg(ap, quad_t *)) = retval;
 413                         else if (lflag)
 414                                 *(va_arg(ap, long *)) = retval;
 415                         else if (zflag)
 416                                 *(va_arg(ap, size_t *)) = retval;
 417                         else if (hflag)
 418                                 *(va_arg(ap, short *)) = retval;
 419                         else if (cflag)
 420                                 *(va_arg(ap, char *)) = retval;
 421                         else
 422                                 *(va_arg(ap, int *)) = retval;
 423                         break;
 424                 case 'o':
 425                         base = 8;
 426                         goto handle_nosign;
 427                 case 'p':
 428                         base = 16;
 429                         sharpflag = (width == 0);
 430                         sign = 0;
 431                         num = (uintptr_t)va_arg(ap, void *);
 432                         goto number;
 433                 case 'q':
 434                         qflag = 1;
 435                         goto reswitch;
 436                 case 'r':
 437                         base = radix;
 438                         if (sign)
 439                                 goto handle_sign;
 440                         goto handle_nosign;
 441                 case 's':
 442                         p = va_arg(ap, char *);
 443                         if (p == NULL)
 444                                 p = "(null)";
 445                         if (!dot)
 446                                 n = strlen (p);
 447                         else
 448                                 for (n = 0; n < dwidth && p[n]; n++)
 449                                         continue;
 450
 451                         width -= n;
 452
 453                         if (!ladjust && width > 0)
 454                                 while (width--)
 455                                         dtrace_debug__putc(padc);
 456                         while (n--)
 457                                 dtrace_debug__putc(*p++);
 458                         if (ladjust && width > 0)
 459                                 while (width--)
 460                                         dtrace_debug__putc(padc);
 461                         break;
 462                 case 't':
 463                         tflag = 1;
 464                         goto reswitch;
 465                 case 'u':
 466                         base = 10;
 467                         goto handle_nosign;
 468                 case 'X':
 469                         upper = 1;
 470                 case 'x':
 471                         base = 16;
 472                         goto handle_nosign;
 473                 case 'y':
 474                         base = 16;
 475                         sign = 1;
 476                         goto handle_sign;
 477                 case 'z':
 478                         zflag = 1;
 479                         goto reswitch;
 480 handle_nosign:
 481                         sign = 0;
 482                         if (jflag)
 483                                 num = va_arg(ap, uintmax_t);
 484                         else if (qflag)
 485                                 num = va_arg(ap, u_quad_t);
 486                         else if (tflag)
 487                                 num = va_arg(ap, ptrdiff_t);
 488                         else if (lflag)
 489                                 num = va_arg(ap, u_long);
 490                         else if (zflag)
 491                                 num = va_arg(ap, size_t);
 492                         else if (hflag)
 493                                 num = (u_short)va_arg(ap, int);
 494                         else if (cflag)
 495                                 num = (u_char)va_arg(ap, int);
 496                         else
 497                                 num = va_arg(ap, u_int);
 498                         goto number;
 499 handle_sign:
 500                         if (jflag)
 501                                 num = va_arg(ap, intmax_t);
 502                         else if (qflag)
 503                                 num = va_arg(ap, quad_t);
 504                         else if (tflag)
 505                                 num = va_arg(ap, ptrdiff_t);
 506                         else if (lflag)
 507                                 num = va_arg(ap, long);
 508                         else if (zflag)
 509                                 num = va_arg(ap, size_t);
 510                         else if (hflag)
 511                                 num = (short)va_arg(ap, int);
 512                         else if (cflag)
 513                                 num = (char)va_arg(ap, int);
 514                         else
 515                                 num = va_arg(ap, int);
 516 number:
 517                         if (sign && (intmax_t)num < 0) {
 518                                 neg = 1;
 519                                 num = -(intmax_t)num;
 520                         }
 521                         p = dtrace_debug_ksprintn(nbuf, num, base, &tmp, upper);
 522                         if (sharpflag && num != 0) {
 523                                 if (base == 8)
 524                                         tmp++;
 525                                 else if (base == 16)
 526                                         tmp += 2;
 527                         }
 528                         if (neg)
 529                                 tmp++;
 530
 531                         if (!ladjust && padc != '0' && width
 532                             && (width -= tmp) > 0)
 533                                 while (width--)
 534                                         dtrace_debug__putc(padc);
 535                         if (neg)
 536                                 dtrace_debug__putc('-');
 537                         if (sharpflag && num != 0) {
 538                                 if (base == 8) {
 539                                         dtrace_debug__putc('0');
 540                                 } else if (base == 16) {
 541                                         dtrace_debug__putc('0');
 542                                         dtrace_debug__putc('x');
 543                                 }
 544                         }
 545                         if (!ladjust && width && (width -= tmp) > 0)
 546                                 while (width--)
 547                                         dtrace_debug__putc(padc);
 548
 549                         while (*p)
 550                                 dtrace_debug__putc(*p--);
 551
 552                         if (ladjust && width && (width -= tmp) > 0)
 553                                 while (width--)
 554                                         dtrace_debug__putc(padc);
 555
 556                         break;
 557                 default:
 558                         while (percent < fmt)
 559                                 dtrace_debug__putc(*percent++);
 560                         /*
 561                          * Since we ignore an formatting argument it is no
 562                          * longer safe to obey the remaining formatting
 563                          * arguments as the arguments will no longer match
 564                          * the format specs.
 565                          */
 566                         stop = 1;
 567                         break;
 568                 }
 569         }
 570
 571         dtrace_debug__putc('\0');
 572 }
 573
 574 void
 575 dtrace_debug_printf(const char *fmt, ...)
 576 {
 577         va_list ap;
 578
 579         dtrace_debug_lock(curcpu);
 580
 581         va_start(ap, fmt);
 582
 583         dtrace_debug_vprintf(fmt, ap);
 584
 585         va_end(ap);
 586
 587         dtrace_debug_unlock(curcpu);
 588 }
 589
 590 #else
 591
 592 #define dtrace_debug_output()
 593 #define dtrace_debug_puts(_s)
 594 #define dtrace_debug_printf(fmt, ...)
 595
 596 #endif