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 #include <machine/atomic.h>
  35
  36 #define DTRACE_DEBUG_BUFR_SIZE  (32 * 1024)
  37
  38 struct dtrace_debug_data {
  39         uintptr_t lock __aligned(CACHE_LINE_SIZE);
  40         char bufr[DTRACE_DEBUG_BUFR_SIZE];
  41         char *first;
  42         char *last;
  43         char *next;
  44 } dtrace_debug_data[MAXCPU];
  45
  46 static char dtrace_debug_bufr[DTRACE_DEBUG_BUFR_SIZE];
  47
  48 static void
  49 dtrace_debug_lock(int cpu)
  50 {
  51          uintptr_t tid;
  52
  53         tid = (uintptr_t)curthread;
  54         spinlock_enter();
  55         while (atomic_cmpset_acq_ptr(&dtrace_debug_data[cpu].lock, 0, tid) == 0)                /* Loop until the lock is obtained. */
  56                 ;
  57 }
  58
  59 static void
  60 dtrace_debug_unlock(int cpu)
  61 {
  62         atomic_store_rel_ptr(&dtrace_debug_data[cpu].lock, 0);
  63         spinlock_exit();
  64 }
  65
  66 static void
  67 dtrace_debug_init(void *dummy)
  68 {
  69         int i;
  70         struct dtrace_debug_data *d;
  71
  72         CPU_FOREACH(i) {
  73                 d = &dtrace_debug_data[i];
  74
  75                 if (d->first == NULL) {
  76                         d->first = d->bufr;
  77                         d->next = d->bufr;
  78                         d->last = d->bufr + DTRACE_DEBUG_BUFR_SIZE - 1;
  79                         *(d->last) = '\0';
  80                 }
  81         }
  82 }
  83
  84 SYSINIT(dtrace_debug_init, SI_SUB_KDTRACE, SI_ORDER_ANY, dtrace_debug_init, NULL);
  85 SYSINIT(dtrace_debug_smpinit, SI_SUB_SMP, SI_ORDER_ANY, dtrace_debug_init, NULL);
  86
  87 static void
  88 dtrace_debug_output(void)
  89 {
  90         char *p;
  91         int i;
  92         struct dtrace_debug_data *d;
  93         uintptr_t count;
  94
  95         CPU_FOREACH(i) {
  96                 dtrace_debug_lock(i);
  97
  98                 d = &dtrace_debug_data[i];
  99
 100                 count = 0;
 101
 102                 if (d->first < d->next) {
 103                         char *p1 = dtrace_debug_bufr;
 104
 105                         count = (uintptr_t) d->next - (uintptr_t) d->first;
 106
 107                         for (p = d->first; p < d->next; p++)
 108                                 *p1++ = *p;
 109                 } else if (d->next > d->first) {
 110                         char *p1 = dtrace_debug_bufr;
 111
 112                         count = (uintptr_t) d->last - (uintptr_t) d->first;
 113
 114                         for (p = d->first; p < d->last; p++)
 115                                 *p1++ = *p;
 116
 117                         count += (uintptr_t) d->next - (uintptr_t) d->bufr;
 118
 119                         for (p = d->bufr; p < d->next; p++)
 120                                 *p1++ = *p;
 121                 }
 122
 123                 d->first = d->bufr;
 124                 d->next = d->bufr;
 125
 126                 dtrace_debug_unlock(i);
 127
 128                 if (count > 0) {
 129                         char *last = dtrace_debug_bufr + count;
 130
 131                         p = dtrace_debug_bufr;
 132
 133                         while (p < last) {
 134                                 if (*p == '\0') {
 135                                         p++;
 136                                         continue;
 137                                 }
 138
 139                                 printf("%s", p);
 140
 141                                 p += strlen(p);
 142                         }
 143                 }
 144         }
 145 }
 146
 147 /*
 148  * Functions below here are called from the probe context, so they can't call
 149  * _any_ functions outside the dtrace module without running foul of the function
 150  * boundary trace provider (fbt). The purpose of these functions is limited to
 151  * buffering debug strings for output when the probe completes on the current CPU.
 152  */
 153
 154 static __inline void
 155 dtrace_debug__putc(int cpu, char c)
 156 {
 157         struct dtrace_debug_data *d;
 158
 159         d = &dtrace_debug_data[cpu];
 160         *d->next++ = c;
 161
 162         if (d->next == d->last)
 163                 d->next = d->bufr;
 164
 165         *(d->next) = '\0';
 166
 167         if (d->next == d->first)
 168                 d->first++;
 169
 170         if (d->first == d->last)
 171                 d->first = d->bufr;
 172 }
 173
 174 static void __used
 175 dtrace_debug_putc(char c)
 176 {
 177         int cpu;
 178
 179         cpu = curcpu;
 180         dtrace_debug_lock(cpu);
 181
 182         dtrace_debug__putc(cpu, c);
 183
 184         dtrace_debug_unlock(cpu);
 185 }
 186
 187 static void __used
 188 dtrace_debug_puts(const char *s)
 189 {
 190         int cpu;
 191
 192         cpu = curcpu;
 193         dtrace_debug_lock(cpu);
 194
 195         while (*s != '\0')
 196                 dtrace_debug__putc(cpu, *s++);
 197
 198         dtrace_debug__putc(cpu, '\0');
 199
 200         dtrace_debug_unlock(cpu);
 201 }
 202
 203 /*
 204  * Snaffled from sys/kern/subr_prf.c
 205  *
 206  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
 207  * order; return an optional length and a pointer to the last character
 208  * written in the buffer (i.e., the first character of the string).
 209  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
 210  */
 211 static char *
 212 dtrace_debug_ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
 213 {
 214         char *p, c;
 215
 216         p = nbuf;
 217         *p = '\0';
 218         do {
 219                 c = hex2ascii(num % base);
 220                 *++p = upper ? toupper(c) : c;
 221         } while (num /= base);
 222         if (lenp)
 223                 *lenp = p - nbuf;
 224         return (p);
 225 }
 226
 227 #define MAXNBUF (sizeof(intmax_t) * NBBY + 1)
 228
 229 static void
 230 dtrace_debug_vprintf(int cpu, const char *fmt, va_list ap)
 231 {
 232         char nbuf[MAXNBUF];
 233         const char *p, *percent, *q;
 234         u_char *up;
 235         int ch, n;
 236         uintmax_t num;
 237         int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
 238         int cflag, hflag, jflag, tflag, zflag;
 239         int dwidth, upper;
 240         int radix = 10;
 241         char padc;
 242         int stop = 0, retval = 0;
 243
 244         num = 0;
 245
 246         if (fmt == NULL)
 247                 fmt = "(fmt null)\n";
 248
 249         for (;;) {
 250                 padc = ' ';
 251                 width = 0;
 252                 while ((ch = (u_char)*fmt++) != '%' || stop) {
 253                         if (ch == '\0') {
 254                                 dtrace_debug__putc(cpu, '\0');
 255                                 return;
 256                         }
 257                         dtrace_debug__putc(cpu, ch);
 258                 }
 259                 percent = fmt - 1;
 260                 qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
 261                 sign = 0; dot = 0; dwidth = 0; upper = 0;
 262                 cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
 263 reswitch:       switch (ch = (u_char)*fmt++) {
 264                 case '.':
 265                         dot = 1;
 266                         goto reswitch;
 267                 case '#':
 268                         sharpflag = 1;
 269                         goto reswitch;
 270                 case '+':
 271                         sign = 1;
 272                         goto reswitch;
 273                 case '-':
 274                         ladjust = 1;
 275                         goto reswitch;
 276                 case '%':
 277                         dtrace_debug__putc(cpu, ch);
 278                         break;
 279                 case '*':
 280                         if (!dot) {
 281                                 width = va_arg(ap, int);
 282                                 if (width < 0) {
 283                                         ladjust = !ladjust;
 284                                         width = -width;
 285                                 }
 286                         } else {
 287                                 dwidth = va_arg(ap, int);
 288                         }
 289                         goto reswitch;
 290                 case '0':
 291                         if (!dot) {
 292                                 padc = '0';
 293                                 goto reswitch;
 294                         }
 295                 case '1': case '2': case '3': case '4':
 296                 case '5': case '6': case '7': case '8': case '9':
 297                                 for (n = 0;; ++fmt) {
 298                                         n = n * 10 + ch - '0';
 299                                         ch = *fmt;
 300                                         if (ch < '0' || ch > '9')
 301                                                 break;
 302                                 }
 303                         if (dot)
 304                                 dwidth = n;
 305                         else
 306                                 width = n;
 307                         goto reswitch;
 308                 case 'b':
 309                         num = (u_int)va_arg(ap, int);
 310                         p = va_arg(ap, char *);
 311                         for (q = dtrace_debug_ksprintn(nbuf, num, *p++, NULL, 0); *q;)
 312                                 dtrace_debug__putc(cpu, *q--);
 313
 314                         if (num == 0)
 315                                 break;
 316
 317                         for (tmp = 0; *p;) {
 318                                 n = *p++;
 319                                 if (num & (1 << (n - 1))) {
 320                                         dtrace_debug__putc(cpu, tmp ? ',' : '<');
 321                                         for (; (n = *p) > ' '; ++p)
 322                                                 dtrace_debug__putc(cpu, n);
 323                                         tmp = 1;
 324                                 } else
 325                                         for (; *p > ' '; ++p)
 326                                                 continue;
 327                         }
 328                         if (tmp)
 329                                 dtrace_debug__putc(cpu, '>');
 330                         break;
 331                 case 'c':
 332                         dtrace_debug__putc(cpu, va_arg(ap, int));
 333                         break;
 334                 case 'D':
 335                         up = va_arg(ap, u_char *);
 336                         p = va_arg(ap, char *);
 337                         if (!width)
 338                                 width = 16;
 339                         while(width--) {
 340                                 dtrace_debug__putc(cpu, hex2ascii(*up >> 4));
 341                                 dtrace_debug__putc(cpu, hex2ascii(*up & 0x0f));
 342                                 up++;
 343                                 if (width)
 344                                         for (q=p;*q;q++)
 345                                                 dtrace_debug__putc(cpu, *q);
 346                         }
 347                         break;
 348                 case 'd':
 349                 case 'i':
 350                         base = 10;
 351                         sign = 1;
 352                         goto handle_sign;
 353                 case 'h':
 354                         if (hflag) {
 355                                 hflag = 0;
 356                                 cflag = 1;
 357                         } else
 358                                 hflag = 1;
 359                         goto reswitch;
 360                 case 'j':
 361                         jflag = 1;
 362                         goto reswitch;
 363                 case 'l':
 364                         if (lflag) {
 365                                 lflag = 0;
 366                                 qflag = 1;
 367                         } else
 368                                 lflag = 1;
 369                         goto reswitch;
 370                 case 'n':
 371                         if (jflag)
 372                                 *(va_arg(ap, intmax_t *)) = retval;
 373                         else if (qflag)
 374                                 *(va_arg(ap, quad_t *)) = retval;
 375                         else if (lflag)
 376                                 *(va_arg(ap, long *)) = retval;
 377                         else if (zflag)
 378                                 *(va_arg(ap, size_t *)) = retval;
 379                         else if (hflag)
 380                                 *(va_arg(ap, short *)) = retval;
 381                         else if (cflag)
 382                                 *(va_arg(ap, char *)) = retval;
 383                         else
 384                                 *(va_arg(ap, int *)) = retval;
 385                         break;
 386                 case 'o':
 387                         base = 8;
 388                         goto handle_nosign;
 389                 case 'p':
 390                         base = 16;
 391                         sharpflag = (width == 0);
 392                         sign = 0;
 393                         num = (uintptr_t)va_arg(ap, void *);
 394                         goto number;
 395                 case 'q':
 396                         qflag = 1;
 397                         goto reswitch;
 398                 case 'r':
 399                         base = radix;
 400                         if (sign)
 401                                 goto handle_sign;
 402                         goto handle_nosign;
 403                 case 's':
 404                         p = va_arg(ap, char *);
 405                         if (p == NULL)
 406                                 p = "(null)";
 407                         if (!dot)
 408                                 n = strlen (p);
 409                         else
 410                                 for (n = 0; n < dwidth && p[n]; n++)
 411                                         continue;
 412
 413                         width -= n;
 414
 415                         if (!ladjust && width > 0)
 416                                 while (width--)
 417                                         dtrace_debug__putc(cpu, padc);
 418                         while (n--)
 419                                 dtrace_debug__putc(cpu, *p++);
 420                         if (ladjust && width > 0)
 421                                 while (width--)
 422                                         dtrace_debug__putc(cpu, padc);
 423                         break;
 424                 case 't':
 425                         tflag = 1;
 426                         goto reswitch;
 427                 case 'u':
 428                         base = 10;
 429                         goto handle_nosign;
 430                 case 'X':
 431                         upper = 1;
 432                 case 'x':
 433                         base = 16;
 434                         goto handle_nosign;
 435                 case 'y':
 436                         base = 16;
 437                         sign = 1;
 438                         goto handle_sign;
 439                 case 'z':
 440                         zflag = 1;
 441                         goto reswitch;
 442 handle_nosign:
 443                         sign = 0;
 444                         if (jflag)
 445                                 num = va_arg(ap, uintmax_t);
 446                         else if (qflag)
 447                                 num = va_arg(ap, u_quad_t);
 448                         else if (tflag)
 449                                 num = va_arg(ap, ptrdiff_t);
 450                         else if (lflag)
 451                                 num = va_arg(ap, u_long);
 452                         else if (zflag)
 453                                 num = va_arg(ap, size_t);
 454                         else if (hflag)
 455                                 num = (u_short)va_arg(ap, int);
 456                         else if (cflag)
 457                                 num = (u_char)va_arg(ap, int);
 458                         else
 459                                 num = va_arg(ap, u_int);
 460                         goto number;
 461 handle_sign:
 462                         if (jflag)
 463                                 num = va_arg(ap, intmax_t);
 464                         else if (qflag)
 465                                 num = va_arg(ap, quad_t);
 466                         else if (tflag)
 467                                 num = va_arg(ap, ptrdiff_t);
 468                         else if (lflag)
 469                                 num = va_arg(ap, long);
 470                         else if (zflag)
 471                                 num = va_arg(ap, size_t);
 472                         else if (hflag)
 473                                 num = (short)va_arg(ap, int);
 474                         else if (cflag)
 475                                 num = (char)va_arg(ap, int);
 476                         else
 477                                 num = va_arg(ap, int);
 478 number:
 479                         if (sign && (intmax_t)num < 0) {
 480                                 neg = 1;
 481                                 num = -(intmax_t)num;
 482                         }
 483                         p = dtrace_debug_ksprintn(nbuf, num, base, &tmp, upper);
 484                         if (sharpflag && num != 0) {
 485                                 if (base == 8)
 486                                         tmp++;
 487                                 else if (base == 16)
 488                                         tmp += 2;
 489                         }
 490                         if (neg)
 491                                 tmp++;
 492
 493                         if (!ladjust && padc != '0' && width
 494                             && (width -= tmp) > 0)
 495                                 while (width--)
 496                                         dtrace_debug__putc(cpu, padc);
 497                         if (neg)
 498                                 dtrace_debug__putc(cpu, '-');
 499                         if (sharpflag && num != 0) {
 500                                 if (base == 8) {
 501                                         dtrace_debug__putc(cpu, '0');
 502                                 } else if (base == 16) {
 503                                         dtrace_debug__putc(cpu, '0');
 504                                         dtrace_debug__putc(cpu, 'x');
 505                                 }
 506                         }
 507                         if (!ladjust && width && (width -= tmp) > 0)
 508                                 while (width--)
 509                                         dtrace_debug__putc(cpu, padc);
 510
 511                         while (*p)
 512                                 dtrace_debug__putc(cpu, *p--);
 513
 514                         if (ladjust && width && (width -= tmp) > 0)
 515                                 while (width--)
 516                                         dtrace_debug__putc(cpu, padc);
 517
 518                         break;
 519                 default:
 520                         while (percent < fmt)
 521                                 dtrace_debug__putc(cpu, *percent++);
 522                         /*
 523                          * Since we ignore an formatting argument it is no
 524                          * longer safe to obey the remaining formatting
 525                          * arguments as the arguments will no longer match
 526                          * the format specs.
 527                          */
 528                         stop = 1;
 529                         break;
 530                 }
 531         }
 532
 533         dtrace_debug__putc(cpu, '\0');
 534 }
 535
 536 void
 537 dtrace_debug_printf(const char *fmt, ...)
 538 {
 539         va_list ap;
 540         int cpu;
 541
 542         cpu = curcpu;
 543         dtrace_debug_lock(cpu);
 544
 545         va_start(ap, fmt);
 546
 547         dtrace_debug_vprintf(cpu, fmt, ap);
 548
 549         va_end(ap);
 550
 551         dtrace_debug_unlock(cpu);
 552 }
 553
 554 #else
 555
 556 #define dtrace_debug_output()
 557 #define dtrace_debug_puts(_s)
 558 #define dtrace_debug_printf(fmt, ...)
 559
 560 #endif