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         CPU_FOREACH(i) {
 112                 d = &dtrace_debug_data[i];
 113
 114                 if (d->first == NULL) {
 115                         d->first = d->bufr;
 116                         d->next = d->bufr;
 117                         d->last = d->bufr + DTRACE_DEBUG_BUFR_SIZE - 1;
 118                         *(d->last) = '\0';
 119                 }
 120         }
 121 }
 122
 123 SYSINIT(dtrace_debug_init, SI_SUB_KDTRACE, SI_ORDER_ANY, dtrace_debug_init, NULL);
 124 SYSINIT(dtrace_debug_smpinit, SI_SUB_SMP, SI_ORDER_ANY, dtrace_debug_init, NULL);
 125
 126 static void
 127 dtrace_debug_output(void)
 128 {
 129         char *p;
 130         int i;
 131         struct dtrace_debug_data *d;
 132         uintptr_t count;
 133
 134         CPU_FOREACH(i) {
 135                 dtrace_debug_lock(i);
 136
 137                 d = &dtrace_debug_data[i];
 138
 139                 count = 0;
 140
 141                 if (d->first < d->next) {
 142                         char *p1 = dtrace_debug_bufr;
 143
 144                         count = (uintptr_t) d->next - (uintptr_t) d->first;
 145
 146                         for (p = d->first; p < d->next; p++)
 147                                 *p1++ = *p;
 148                 } else if (d->next > d->first) {
 149                         char *p1 = dtrace_debug_bufr;
 150
 151                         count = (uintptr_t) d->last - (uintptr_t) d->first;
 152
 153                         for (p = d->first; p < d->last; p++)
 154                                 *p1++ = *p;
 155
 156                         count += (uintptr_t) d->next - (uintptr_t) d->bufr;
 157
 158                         for (p = d->bufr; p < d->next; p++)
 159                                 *p1++ = *p;
 160                 }
 161
 162                 d->first = d->bufr;
 163                 d->next = d->bufr;
 164
 165                 dtrace_debug_unlock(i);
 166
 167                 if (count > 0) {
 168                         char *last = dtrace_debug_bufr + count;
 169
 170                         p = dtrace_debug_bufr;
 171
 172                         while (p < last) {
 173                                 if (*p == '\0') {
 174                                         p++;
 175                                         continue;
 176                                 }
 177
 178                                 printf("%s", p);
 179
 180                                 p += strlen(p);
 181                         }
 182                 }
 183         }
 184 }
 185
 186 /*
 187  * Functions below here are called from the probe context, so they can't call
 188  * _any_ functions outside the dtrace module without running foul of the function
 189  * boundary trace provider (fbt). The purpose of these functions is limited to
 190  * buffering debug strings for output when the probe completes on the current CPU.
 191  */
 192
 193 static __inline void
 194 dtrace_debug__putc(char c)
 195 {
 196         struct dtrace_debug_data *d = &dtrace_debug_data[curcpu];
 197
 198         *d->next++ = c;
 199
 200         if (d->next == d->last)
 201                 d->next = d->bufr;
 202
 203         *(d->next) = '\0';
 204
 205         if (d->next == d->first)
 206                 d->first++;
 207
 208         if (d->first == d->last)
 209                 d->first = d->bufr;
 210 }
 211
 212 static void __used
 213 dtrace_debug_putc(char c)
 214 {
 215         dtrace_debug_lock(curcpu);
 216
 217         dtrace_debug__putc(c);
 218
 219         dtrace_debug_unlock(curcpu);
 220 }
 221
 222 static void __used
 223 dtrace_debug_puts(const char *s)
 224 {
 225         dtrace_debug_lock(curcpu);
 226
 227         while (*s != '\0')
 228                 dtrace_debug__putc(*s++);
 229
 230         dtrace_debug__putc('\0');
 231
 232         dtrace_debug_unlock(curcpu);
 233 }
 234
 235 /*
 236  * Snaffled from sys/kern/subr_prf.c
 237  *
 238  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 239  * order; return an optional length and a pointer to the last character
 240  * written in the buffer (i.e., the first character of the string).
 241  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 242  */
 243 static char *
 244 dtrace_debug_ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
 245 {
 246         char *p, c;
 247
 248         p = nbuf;
 249         *p = '\0';
 250         do {
 251                 c = hex2ascii(num % base);
 252                 *++p = upper ? toupper(c) : c;
 253         } while (num /= base);
 254         if (lenp)
 255                 *lenp = p - nbuf;
 256         return (p);
 257 }
 258
 259 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1)
 260
 261 static void
 262 dtrace_debug_vprintf(const char *fmt, va_list ap)
 263 {
 264         char nbuf[MAXNBUF];
 265         const char *p, *percent, *q;
 266         u_char *up;
 267         int ch, n;
 268         uintmax_t num;
 269         int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
 270         int cflag, hflag, jflag, tflag, zflag;
 271         int dwidth, upper;
 272         int radix = 10;
 273         char padc;
 274         int stop = 0, retval = 0;
 275
 276         num = 0;
 277
 278         if (fmt == NULL)
 279                 fmt = "(fmt null)\n";
 280
 281         for (;;) {
 282                 padc = ' ';
 283                 width = 0;
 284                 while ((ch = (u_char)*fmt++) != '%' || stop) {
 285                         if (ch == '\0') {
 286                                 dtrace_debug__putc('\0');
 287                                 return;
 288                         }
 289                         dtrace_debug__putc(ch);
 290                 }
 291                 percent = fmt - 1;
 292                 qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
 293                 sign = 0; dot = 0; dwidth = 0; upper = 0;
 294                 cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
 295 reswitch:       switch (ch = (u_char)*fmt++) {
 296                 case '.':
 297                         dot = 1;
 298                         goto reswitch;
 299                 case '#':
 300                         sharpflag = 1;
 301                         goto reswitch;
 302                 case '+':
 303                         sign = 1;
 304                         goto reswitch;
 305                 case '-':
 306                         ladjust = 1;
 307                         goto reswitch;
 308                 case '%':
 309                         dtrace_debug__putc(ch);
 310                         break;
 311                 case '*':
 312                         if (!dot) {
 313                                 width = va_arg(ap, int);
 314                                 if (width < 0) {
 315                                         ladjust = !ladjust;
 316                                         width = -width;
 317                                 }
 318                         } else {
 319                                 dwidth = va_arg(ap, int);
 320                         }
 321                         goto reswitch;
 322                 case '0':
 323                         if (!dot) {
 324                                 padc = '0';
 325                                 goto reswitch;
 326                         }
 327                 case '1': case '2': case '3': case '4':
 328                 case '5': case '6': case '7': case '8': case '9':
 329                                 for (n = 0;; ++fmt) {
 330                                         n = n * 10 + ch - '0';
 331                                         ch = *fmt;
 332                                         if (ch < '0' || ch > '9')
 333                                                 break;
 334                                 }
 335                         if (dot)
 336                                 dwidth = n;
 337                         else
 338                                 width = n;
 339                         goto reswitch;
 340                 case 'b':
 341                         num = (u_int)va_arg(ap, int);
 342                         p = va_arg(ap, char *);
 343                         for (q = dtrace_debug_ksprintn(nbuf, num, *p++, NULL, 0); *q;)
 344                                 dtrace_debug__putc(*q--);
 345
 346                         if (num == 0)
 347                                 break;
 348
 349                         for (tmp = 0; *p;) {
 350                                 n = *p++;
 351                                 if (num & (1 << (n - 1))) {
 352                                         dtrace_debug__putc(tmp ? ',' : '<');
 353                                         for (; (n = *p) > ' '; ++p)
 354                                                 dtrace_debug__putc(n);
 355                                         tmp = 1;
 356                                 } else
 357                                         for (; *p > ' '; ++p)
 358                                                 continue;
 359                         }
 360                         if (tmp)
 361                                 dtrace_debug__putc('>');
 362                         break;
 363                 case 'c':
 364                         dtrace_debug__putc(va_arg(ap, int));
 365                         break;
 366                 case 'D':
 367                         up = va_arg(ap, u_char *);
 368                         p = va_arg(ap, char *);
 369                         if (!width)
 370                                 width = 16;
 371                         while(width--) {
 372                                 dtrace_debug__putc(hex2ascii(*up >> 4));
 373                                 dtrace_debug__putc(hex2ascii(*up & 0x0f));
 374                                 up++;
 375                                 if (width)
 376                                         for (q=p;*q;q++)
 377                                                 dtrace_debug__putc(*q);
 378                         }
 379                         break;
 380                 case 'd':
 381                 case 'i':
 382                         base = 10;
 383                         sign = 1;
 384                         goto handle_sign;
 385                 case 'h':
 386                         if (hflag) {
 387                                 hflag = 0;
 388                                 cflag = 1;
 389                         } else
 390                                 hflag = 1;
 391                         goto reswitch;
 392                 case 'j':
 393                         jflag = 1;
 394                         goto reswitch;
 395                 case 'l':
 396                         if (lflag) {
 397                                 lflag = 0;
 398                                 qflag = 1;
 399                         } else
 400                                 lflag = 1;
 401                         goto reswitch;
 402                 case 'n':
 403                         if (jflag)
 404                                 *(va_arg(ap, intmax_t *)) = retval;
 405                         else if (qflag)
 406                                 *(va_arg(ap, quad_t *)) = retval;
 407                         else if (lflag)
 408                                 *(va_arg(ap, long *)) = retval;
 409                         else if (zflag)
 410                                 *(va_arg(ap, size_t *)) = retval;
 411                         else if (hflag)
 412                                 *(va_arg(ap, short *)) = retval;
 413                         else if (cflag)
 414                                 *(va_arg(ap, char *)) = retval;
 415                         else
 416                                 *(va_arg(ap, int *)) = retval;
 417                         break;
 418                 case 'o':
 419                         base = 8;
 420                         goto handle_nosign;
 421                 case 'p':
 422                         base = 16;
 423                         sharpflag = (width == 0);
 424                         sign = 0;
 425                         num = (uintptr_t)va_arg(ap, void *);
 426                         goto number;
 427                 case 'q':
 428                         qflag = 1;
 429                         goto reswitch;
 430                 case 'r':
 431                         base = radix;
 432                         if (sign)
 433                                 goto handle_sign;
 434                         goto handle_nosign;
 435                 case 's':
 436                         p = va_arg(ap, char *);
 437                         if (p == NULL)
 438                                 p = "(null)";
 439                         if (!dot)
 440                                 n = strlen (p);
 441                         else
 442                                 for (n = 0; n < dwidth && p[n]; n++)
 443                                         continue;
 444
 445                         width -= n;
 446
 447                         if (!ladjust && width > 0)
 448                                 while (width--)
 449                                         dtrace_debug__putc(padc);
 450                         while (n--)
 451                                 dtrace_debug__putc(*p++);
 452                         if (ladjust && width > 0)
 453                                 while (width--)
 454                                         dtrace_debug__putc(padc);
 455                         break;
 456                 case 't':
 457                         tflag = 1;
 458                         goto reswitch;
 459                 case 'u':
 460                         base = 10;
 461                         goto handle_nosign;
 462                 case 'X':
 463                         upper = 1;
 464                 case 'x':
 465                         base = 16;
 466                         goto handle_nosign;
 467                 case 'y':
 468                         base = 16;
 469                         sign = 1;
 470                         goto handle_sign;
 471                 case 'z':
 472                         zflag = 1;
 473                         goto reswitch;
 474 handle_nosign:
 475                         sign = 0;
 476                         if (jflag)
 477                                 num = va_arg(ap, uintmax_t);
 478                         else if (qflag)
 479                                 num = va_arg(ap, u_quad_t);
 480                         else if (tflag)
 481                                 num = va_arg(ap, ptrdiff_t);
 482                         else if (lflag)
 483                                 num = va_arg(ap, u_long);
 484                         else if (zflag)
 485                                 num = va_arg(ap, size_t);
 486                         else if (hflag)
 487                                 num = (u_short)va_arg(ap, int);
 488                         else if (cflag)
 489                                 num = (u_char)va_arg(ap, int);
 490                         else
 491                                 num = va_arg(ap, u_int);
 492                         goto number;
 493 handle_sign:
 494                         if (jflag)
 495                                 num = va_arg(ap, intmax_t);
 496                         else if (qflag)
 497                                 num = va_arg(ap, quad_t);
 498                         else if (tflag)
 499                                 num = va_arg(ap, ptrdiff_t);
 500                         else if (lflag)
 501                                 num = va_arg(ap, long);
 502                         else if (zflag)
 503                                 num = va_arg(ap, size_t);
 504                         else if (hflag)
 505                                 num = (short)va_arg(ap, int);
 506                         else if (cflag)
 507                                 num = (char)va_arg(ap, int);
 508                         else
 509                                 num = va_arg(ap, int);
 510 number:
 511                         if (sign && (intmax_t)num < 0) {
 512                                 neg = 1;
 513                                 num = -(intmax_t)num;
 514                         }
 515                         p = dtrace_debug_ksprintn(nbuf, num, base, &tmp, upper);
 516                         if (sharpflag && num != 0) {
 517                                 if (base == 8)
 518                                         tmp++;
 519                                 else if (base == 16)
 520                                         tmp += 2;
 521                         }
 522                         if (neg)
 523                                 tmp++;
 524
 525                         if (!ladjust && padc != '0' && width
 526                             && (width -= tmp) > 0)
 527                                 while (width--)
 528                                         dtrace_debug__putc(padc);
 529                         if (neg)
 530                                 dtrace_debug__putc('-');
 531                         if (sharpflag && num != 0) {
 532                                 if (base == 8) {
 533                                         dtrace_debug__putc('0');
 534                                 } else if (base == 16) {
 535                                         dtrace_debug__putc('0');
 536                                         dtrace_debug__putc('x');
 537                                 }
 538                         }
 539                         if (!ladjust && width && (width -= tmp) > 0)
 540                                 while (width--)
 541                                         dtrace_debug__putc(padc);
 542
 543                         while (*p)
 544                                 dtrace_debug__putc(*p--);
 545
 546                         if (ladjust && width && (width -= tmp) > 0)
 547                                 while (width--)
 548                                         dtrace_debug__putc(padc);
 549
 550                         break;
 551                 default:
 552                         while (percent < fmt)
 553                                 dtrace_debug__putc(*percent++);
 554                         /*
 555                          * Since we ignore an formatting argument it is no
 556                          * longer safe to obey the remaining formatting
 557                          * arguments as the arguments will no longer match
 558                          * the format specs.
 559                          */
 560                         stop = 1;
 561                         break;
 562                 }
 563         }
 564
 565         dtrace_debug__putc('\0');
 566 }
 567
 568 void
 569 dtrace_debug_printf(const char *fmt, ...)
 570 {
 571         va_list ap;
 572
 573         dtrace_debug_lock(curcpu);
 574
 575         va_start(ap, fmt);
 576
 577         dtrace_debug_vprintf(fmt, ap);
 578
 579         va_end(ap);
 580
 581         dtrace_debug_unlock(curcpu);
 582 }
 583
 584 #else
 585
 586 #define dtrace_debug_output()
 587 #define dtrace_debug_puts(_s)
 588 #define dtrace_debug_printf(fmt, ...)
 589
 590 #endif