lib/dynamic_debug.c

   1 /*
   2  * lib/dynamic_debug.c
   3  *
   4  * make pr_debug()/dev_dbg() calls runtime configurable based upon their
   5  * source module.
   6  *
   7  * Copyright (C) 2008 Jason Baron <jbaron@redhat.com>
   8  * By Greg Banks <gnb@melbourne.sgi.com>
   9  * Copyright (c) 2008 Silicon Graphics Inc.  All Rights Reserved.
  10  * Copyright (C) 2011 Bart Van Assche.  All Rights Reserved.
  11  * Copyright (C) 2013 Du, Changbin <changbin.du@gmail.com>
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/types.h>
  21 #include <linux/mutex.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/list.h>
  25 #include <linux/sysctl.h>
  26 #include <linux/ctype.h>
  27 #include <linux/string.h>
  28 #include <linux/parser.h>
  29 #include <linux/string_helpers.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/dynamic_debug.h>
  32 #include <linux/debugfs.h>
  33 #include <linux/slab.h>
  34 #include <linux/jump_label.h>
  35 #include <linux/hardirq.h>
  36 #include <linux/sched.h>
  37 #include <linux/device.h>
  38 #include <linux/netdevice.h>
  39
  40 #include <rdma/ib_verbs.h>
  41
  42 extern struct _ddebug __start___verbose[];
  43 extern struct _ddebug __stop___verbose[];
  44
  45 struct ddebug_table {
  46         struct list_head link;
  47         const char *mod_name;
  48         unsigned int num_ddebugs;
  49         struct _ddebug *ddebugs;
  50 };
  51
  52 struct ddebug_query {
  53         const char *filename;
  54         const char *module;
  55         const char *function;
  56         const char *format;
  57         unsigned int first_lineno, last_lineno;
  58 };
  59
  60 struct ddebug_iter {
  61         struct ddebug_table *table;
  62         unsigned int idx;
  63 };
  64
  65 static DEFINE_MUTEX(ddebug_lock);
  66 static LIST_HEAD(ddebug_tables);
  67 static int verbose;
  68 module_param(verbose, int, 0644);
  69
  70 /* Return the path relative to source root */
  71 static inline const char *trim_prefix(const char *path)
  72 {
  73         int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");
  74
  75         if (strncmp(path, __FILE__, skip))
  76                 skip = 0; /* prefix mismatch, don't skip */
  77
  78         return path + skip;
  79 }
  80
  81 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
  82         { _DPRINTK_FLAGS_PRINT, 'p' },
  83         { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
  84         { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
  85         { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
  86         { _DPRINTK_FLAGS_INCL_TID, 't' },
  87         { _DPRINTK_FLAGS_NONE, '_' },
  88 };
  89
  90 /* format a string into buf[] which describes the _ddebug's flags */
  91 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
  92                                     size_t maxlen)
  93 {
  94         char *p = buf;
  95         int i;
  96
  97         BUG_ON(maxlen < 6);
  98         for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
  99                 if (dp->flags & opt_array[i].flag)
 100                         *p++ = opt_array[i].opt_char;
 101         if (p == buf)
 102                 *p++ = '_';
 103         *p = '\0';
 104
 105         return buf;
 106 }
 107
 108 #define vpr_info(fmt, ...)                                      \
 109 do {                                                            \
 110         if (verbose)                                            \
 111                 pr_info(fmt, ##__VA_ARGS__);                    \
 112 } while (0)
 113
 114 static void vpr_info_dq(const struct ddebug_query *query, const char *msg)
 115 {
 116         /* trim any trailing newlines */
 117         int fmtlen = 0;
 118
 119         if (query->format) {
 120                 fmtlen = strlen(query->format);
 121                 while (fmtlen && query->format[fmtlen - 1] == '\n')
 122                         fmtlen--;
 123         }
 124
 125         vpr_info("%s: func=\"%s\" file=\"%s\" module=\"%s\" format=\"%.*s\" lineno=%u-%u\n",
 126                  msg,
 127                  query->function ? query->function : "",
 128                  query->filename ? query->filename : "",
 129                  query->module ? query->module : "",
 130                  fmtlen, query->format ? query->format : "",
 131                  query->first_lineno, query->last_lineno);
 132 }
 133
 134 /*
 135  * Search the tables for _ddebug's which match the given `query' and
 136  * apply the `flags' and `mask' to them.  Returns number of matching
 137  * callsites, normally the same as number of changes.  If verbose,
 138  * logs the changes.  Takes ddebug_lock.
 139  */
 140 static int ddebug_change(const struct ddebug_query *query,
 141                         unsigned int flags, unsigned int mask)
 142 {
 143         int i;
 144         struct ddebug_table *dt;
 145         unsigned int newflags;
 146         unsigned int nfound = 0;
 147         char flagbuf[10];
 148
 149         /* search for matching ddebugs */
 150         mutex_lock(&ddebug_lock);
 151         list_for_each_entry(dt, &ddebug_tables, link) {
 152
 153                 /* match against the module name */
 154                 if (query->module &&
 155                     !match_wildcard(query->module, dt->mod_name))
 156                         continue;
 157
 158                 for (i = 0; i < dt->num_ddebugs; i++) {
 159                         struct _ddebug *dp = &dt->ddebugs[i];
 160
 161                         /* match against the source filename */
 162                         if (query->filename &&
 163                             !match_wildcard(query->filename, dp->filename) &&
 164                             !match_wildcard(query->filename,
 165                                            kbasename(dp->filename)) &&
 166                             !match_wildcard(query->filename,
 167                                            trim_prefix(dp->filename)))
 168                                 continue;
 169
 170                         /* match against the function */
 171                         if (query->function &&
 172                             !match_wildcard(query->function, dp->function))
 173                                 continue;
 174
 175                         /* match against the format */
 176                         if (query->format &&
 177                             !strstr(dp->format, query->format))
 178                                 continue;
 179
 180                         /* match against the line number range */
 181                         if (query->first_lineno &&
 182                             dp->lineno < query->first_lineno)
 183                                 continue;
 184                         if (query->last_lineno &&
 185                             dp->lineno > query->last_lineno)
 186                                 continue;
 187
 188                         nfound++;
 189
 190                         newflags = (dp->flags & mask) | flags;
 191                         if (newflags == dp->flags)
 192                                 continue;
 193 #ifdef CONFIG_JUMP_LABEL
 194                         if (dp->flags & _DPRINTK_FLAGS_PRINT) {
 195                                 if (!(flags & _DPRINTK_FLAGS_PRINT))
 196                                         static_branch_disable(&dp->key.dd_key_true);
 197                         } else if (flags & _DPRINTK_FLAGS_PRINT)
 198                                 static_branch_enable(&dp->key.dd_key_true);
 199 #endif
 200                         dp->flags = newflags;
 201                         vpr_info("changed %s:%d [%s]%s =%s\n",
 202                                  trim_prefix(dp->filename), dp->lineno,
 203                                  dt->mod_name, dp->function,
 204                                  ddebug_describe_flags(dp, flagbuf,
 205                                                        sizeof(flagbuf)));
 206                 }
 207         }
 208         mutex_unlock(&ddebug_lock);
 209
 210         if (!nfound && verbose)
 211                 pr_info("no matches for query\n");
 212
 213         return nfound;
 214 }
 215
 216 /*
 217  * Split the buffer `buf' into space-separated words.
 218  * Handles simple " and ' quoting, i.e. without nested,
 219  * embedded or escaped \".  Return the number of words
 220  * or <0 on error.
 221  */
 222 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 223 {
 224         int nwords = 0;
 225
 226         while (*buf) {
 227                 char *end;
 228
 229                 /* Skip leading whitespace */
 230                 buf = skip_spaces(buf);
 231                 if (!*buf)
 232                         break;  /* oh, it was trailing whitespace */
 233                 if (*buf == '#')
 234                         break;  /* token starts comment, skip rest of line */
 235
 236                 /* find `end' of word, whitespace separated or quoted */
 237                 if (*buf == '"' || *buf == '\'') {
 238                         int quote = *buf++;
 239                         for (end = buf; *end && *end != quote; end++)
 240                                 ;
 241                         if (!*end) {
 242                                 pr_err("unclosed quote: %s\n", buf);
 243                                 return -EINVAL; /* unclosed quote */
 244                         }
 245                 } else {
 246                         for (end = buf; *end && !isspace(*end); end++)
 247                                 ;
 248                         BUG_ON(end == buf);
 249                 }
 250
 251                 /* `buf' is start of word, `end' is one past its end */
 252                 if (nwords == maxwords) {
 253                         pr_err("too many words, legal max <=%d\n", maxwords);
 254                         return -EINVAL; /* ran out of words[] before bytes */
 255                 }
 256                 if (*end)
 257                         *end++ = '\0';  /* terminate the word */
 258                 words[nwords++] = buf;
 259                 buf = end;
 260         }
 261
 262         if (verbose) {
 263                 int i;
 264                 pr_info("split into words:");
 265                 for (i = 0; i < nwords; i++)
 266                         pr_cont(" \"%s\"", words[i]);
 267                 pr_cont("\n");
 268         }
 269
 270         return nwords;
 271 }
 272
 273 /*
 274  * Parse a single line number.  Note that the empty string ""
 275  * is treated as a special case and converted to zero, which
 276  * is later treated as a "don't care" value.
 277  */
 278 static inline int parse_lineno(const char *str, unsigned int *val)
 279 {
 280         BUG_ON(str == NULL);
 281         if (*str == '\0') {
 282                 *val = 0;
 283                 return 0;
 284         }
 285         if (kstrtouint(str, 10, val) < 0) {
 286                 pr_err("bad line-number: %s\n", str);
 287                 return -EINVAL;
 288         }
 289         return 0;
 290 }
 291
 292 static int check_set(const char **dest, char *src, char *name)
 293 {
 294         int rc = 0;
 295
 296         if (*dest) {
 297                 rc = -EINVAL;
 298                 pr_err("match-spec:%s val:%s overridden by %s\n",
 299                        name, *dest, src);
 300         }
 301         *dest = src;
 302         return rc;
 303 }
 304
 305 /*
 306  * Parse words[] as a ddebug query specification, which is a series
 307  * of (keyword, value) pairs chosen from these possibilities:
 308  *
 309  * func <function-name>
 310  * file <full-pathname>
 311  * file <base-filename>
 312  * module <module-name>
 313  * format <escaped-string-to-find-in-format>
 314  * line <lineno>
 315  * line <first-lineno>-<last-lineno> // where either may be empty
 316  *
 317  * Only 1 of each type is allowed.
 318  * Returns 0 on success, <0 on error.
 319  */
 320 static int ddebug_parse_query(char *words[], int nwords,
 321                         struct ddebug_query *query, const char *modname)
 322 {
 323         unsigned int i;
 324         int rc = 0;
 325
 326         /* check we have an even number of words */
 327         if (nwords % 2 != 0) {
 328                 pr_err("expecting pairs of match-spec <value>\n");
 329                 return -EINVAL;
 330         }
 331         memset(query, 0, sizeof(*query));
 332
 333         if (modname)
 334                 /* support $modname.dyndbg=<multiple queries> */
 335                 query->module = modname;
 336
 337         for (i = 0; i < nwords; i += 2) {
 338                 if (!strcmp(words[i], "func")) {
 339                         rc = check_set(&query->function, words[i+1], "func");
 340                 } else if (!strcmp(words[i], "file")) {
 341                         rc = check_set(&query->filename, words[i+1], "file");
 342                 } else if (!strcmp(words[i], "module")) {
 343                         rc = check_set(&query->module, words[i+1], "module");
 344                 } else if (!strcmp(words[i], "format")) {
 345                         string_unescape_inplace(words[i+1], UNESCAPE_SPACE |
 346                                                             UNESCAPE_OCTAL |
 347                                                             UNESCAPE_SPECIAL);
 348                         rc = check_set(&query->format, words[i+1], "format");
 349                 } else if (!strcmp(words[i], "line")) {
 350                         char *first = words[i+1];
 351                         char *last = strchr(first, '-');
 352                         if (query->first_lineno || query->last_lineno) {
 353                                 pr_err("match-spec: line used 2x\n");
 354                                 return -EINVAL;
 355                         }
 356                         if (last)
 357                                 *last++ = '\0';
 358                         if (parse_lineno(first, &query->first_lineno) < 0)
 359                                 return -EINVAL;
 360                         if (last) {
 361                                 /* range <first>-<last> */
 362                                 if (parse_lineno(last, &query->last_lineno) < 0)
 363                                         return -EINVAL;
 364
 365                                 /* special case for last lineno not specified */
 366                                 if (query->last_lineno == 0)
 367                                         query->last_lineno = UINT_MAX;
 368
 369                                 if (query->last_lineno < query->first_lineno) {
 370                                         pr_err("last-line:%d < 1st-line:%d\n",
 371                                                 query->last_lineno,
 372                                                 query->first_lineno);
 373                                         return -EINVAL;
 374                                 }
 375                         } else {
 376                                 query->last_lineno = query->first_lineno;
 377                         }
 378                 } else {
 379                         pr_err("unknown keyword \"%s\"\n", words[i]);
 380                         return -EINVAL;
 381                 }
 382                 if (rc)
 383                         return rc;
 384         }
 385         vpr_info_dq(query, "parsed");
 386         return 0;
 387 }
 388
 389 /*
 390  * Parse `str' as a flags specification, format [-+=][p]+.
 391  * Sets up *maskp and *flagsp to be used when changing the
 392  * flags fields of matched _ddebug's.  Returns 0 on success
 393  * or <0 on error.
 394  */
 395 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
 396                                unsigned int *maskp)
 397 {
 398         unsigned flags = 0;
 399         int op = '=', i;
 400
 401         switch (*str) {
 402         case '+':
 403         case '-':
 404         case '=':
 405                 op = *str++;
 406                 break;
 407         default:
 408                 pr_err("bad flag-op %c, at start of %s\n", *str, str);
 409                 return -EINVAL;
 410         }
 411         vpr_info("op='%c'\n", op);
 412
 413         for (; *str ; ++str) {
 414                 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
 415                         if (*str == opt_array[i].opt_char) {
 416                                 flags |= opt_array[i].flag;
 417                                 break;
 418                         }
 419                 }
 420                 if (i < 0) {
 421                         pr_err("unknown flag '%c' in \"%s\"\n", *str, str);
 422                         return -EINVAL;
 423                 }
 424         }
 425         vpr_info("flags=0x%x\n", flags);
 426
 427         /* calculate final *flagsp, *maskp according to mask and op */
 428         switch (op) {
 429         case '=':
 430                 *maskp = 0;
 431                 *flagsp = flags;
 432                 break;
 433         case '+':
 434                 *maskp = ~0U;
 435                 *flagsp = flags;
 436                 break;
 437         case '-':
 438                 *maskp = ~flags;
 439                 *flagsp = 0;
 440                 break;
 441         }
 442         vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
 443         return 0;
 444 }
 445
 446 static int ddebug_exec_query(char *query_string, const char *modname)
 447 {
 448         unsigned int flags = 0, mask = 0;
 449         struct ddebug_query query;
 450 #define MAXWORDS 9
 451         int nwords, nfound;
 452         char *words[MAXWORDS];
 453
 454         nwords = ddebug_tokenize(query_string, words, MAXWORDS);
 455         if (nwords <= 0) {
 456                 pr_err("tokenize failed\n");
 457                 return -EINVAL;
 458         }
 459         /* check flags 1st (last arg) so query is pairs of spec,val */
 460         if (ddebug_parse_flags(words[nwords-1], &flags, &mask)) {
 461                 pr_err("flags parse failed\n");
 462                 return -EINVAL;
 463         }
 464         if (ddebug_parse_query(words, nwords-1, &query, modname)) {
 465                 pr_err("query parse failed\n");
 466                 return -EINVAL;
 467         }
 468         /* actually go and implement the change */
 469         nfound = ddebug_change(&query, flags, mask);
 470         vpr_info_dq(&query, nfound ? "applied" : "no-match");
 471
 472         return nfound;
 473 }
 474
 475 /* handle multiple queries in query string, continue on error, return
 476    last error or number of matching callsites.  Module name is either
 477    in param (for boot arg) or perhaps in query string.
 478 */
 479 static int ddebug_exec_queries(char *query, const char *modname)
 480 {
 481         char *split;
 482         int i, errs = 0, exitcode = 0, rc, nfound = 0;
 483
 484         for (i = 0; query; query = split) {
 485                 split = strpbrk(query, ";\n");
 486                 if (split)
 487                         *split++ = '\0';
 488
 489                 query = skip_spaces(query);
 490                 if (!query || !*query || *query == '#')
 491                         continue;
 492
 493                 vpr_info("query %d: \"%s\"\n", i, query);
 494
 495                 rc = ddebug_exec_query(query, modname);
 496                 if (rc < 0) {
 497                         errs++;
 498                         exitcode = rc;
 499                 } else {
 500                         nfound += rc;
 501                 }
 502                 i++;
 503         }
 504         vpr_info("processed %d queries, with %d matches, %d errs\n",
 505                  i, nfound, errs);
 506
 507         if (exitcode)
 508                 return exitcode;
 509         return nfound;
 510 }
 511
 512 #define PREFIX_SIZE 64
 513
 514 static int remaining(int wrote)
 515 {
 516         if (PREFIX_SIZE - wrote > 0)
 517                 return PREFIX_SIZE - wrote;
 518         return 0;
 519 }
 520
 521 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
 522 {
 523         int pos_after_tid;
 524         int pos = 0;
 525
 526         *buf = '\0';
 527
 528         if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
 529                 if (in_interrupt())
 530                         pos += snprintf(buf + pos, remaining(pos), "<intr> ");
 531                 else
 532                         pos += snprintf(buf + pos, remaining(pos), "[%d] ",
 533                                         task_pid_vnr(current));
 534         }
 535         pos_after_tid = pos;
 536         if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
 537                 pos += snprintf(buf + pos, remaining(pos), "%s:",
 538                                 desc->modname);
 539         if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
 540                 pos += snprintf(buf + pos, remaining(pos), "%s:",
 541                                 desc->function);
 542         if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
 543                 pos += snprintf(buf + pos, remaining(pos), "%d:",
 544                                 desc->lineno);
 545         if (pos - pos_after_tid)
 546                 pos += snprintf(buf + pos, remaining(pos), " ");
 547         if (pos >= PREFIX_SIZE)
 548                 buf[PREFIX_SIZE - 1] = '\0';
 549
 550         return buf;
 551 }
 552
 553 void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
 554 {
 555         va_list args;
 556         struct va_format vaf;
 557         char buf[PREFIX_SIZE];
 558
 559         BUG_ON(!descriptor);
 560         BUG_ON(!fmt);
 561
 562         va_start(args, fmt);
 563
 564         vaf.fmt = fmt;
 565         vaf.va = &args;
 566
 567         printk(KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
 568
 569         va_end(args);
 570 }
 571 EXPORT_SYMBOL(__dynamic_pr_debug);
 572
 573 void __dynamic_dev_dbg(struct _ddebug *descriptor,
 574                       const struct device *dev, const char *fmt, ...)
 575 {
 576         struct va_format vaf;
 577         va_list args;
 578
 579         BUG_ON(!descriptor);
 580         BUG_ON(!fmt);
 581
 582         va_start(args, fmt);
 583
 584         vaf.fmt = fmt;
 585         vaf.va = &args;
 586
 587         if (!dev) {
 588                 printk(KERN_DEBUG "(NULL device *): %pV", &vaf);
 589         } else {
 590                 char buf[PREFIX_SIZE];
 591
 592                 dev_printk_emit(LOGLEVEL_DEBUG, dev, "%s%s %s: %pV",
 593                                 dynamic_emit_prefix(descriptor, buf),
 594                                 dev_driver_string(dev), dev_name(dev),
 595                                 &vaf);
 596         }
 597
 598         va_end(args);
 599 }
 600 EXPORT_SYMBOL(__dynamic_dev_dbg);
 601
 602 #ifdef CONFIG_NET
 603
 604 void __dynamic_netdev_dbg(struct _ddebug *descriptor,
 605                           const struct net_device *dev, const char *fmt, ...)
 606 {
 607         struct va_format vaf;
 608         va_list args;
 609
 610         BUG_ON(!descriptor);
 611         BUG_ON(!fmt);
 612
 613         va_start(args, fmt);
 614
 615         vaf.fmt = fmt;
 616         vaf.va = &args;
 617
 618         if (dev && dev->dev.parent) {
 619                 char buf[PREFIX_SIZE];
 620
 621                 dev_printk_emit(LOGLEVEL_DEBUG, dev->dev.parent,
 622                                 "%s%s %s %s%s: %pV",
 623                                 dynamic_emit_prefix(descriptor, buf),
 624                                 dev_driver_string(dev->dev.parent),
 625                                 dev_name(dev->dev.parent),
 626                                 netdev_name(dev), netdev_reg_state(dev),
 627                                 &vaf);
 628         } else if (dev) {
 629                 printk(KERN_DEBUG "%s%s: %pV", netdev_name(dev),
 630                        netdev_reg_state(dev), &vaf);
 631         } else {
 632                 printk(KERN_DEBUG "(NULL net_device): %pV", &vaf);
 633         }
 634
 635         va_end(args);
 636 }
 637 EXPORT_SYMBOL(__dynamic_netdev_dbg);
 638
 639 #endif
 640
 641 #if IS_ENABLED(CONFIG_INFINIBAND)
 642
 643 void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 644                          const struct ib_device *ibdev, const char *fmt, ...)
 645 {
 646         struct va_format vaf;
 647         va_list args;
 648
 649         va_start(args, fmt);
 650
 651         vaf.fmt = fmt;
 652         vaf.va = &args;
 653
 654         if (ibdev && ibdev->dev.parent) {
 655                 char buf[PREFIX_SIZE];
 656
 657                 dev_printk_emit(LOGLEVEL_DEBUG, ibdev->dev.parent,
 658                                 "%s%s %s %s: %pV",
 659                                 dynamic_emit_prefix(descriptor, buf),
 660                                 dev_driver_string(ibdev->dev.parent),
 661                                 dev_name(ibdev->dev.parent),
 662                                 dev_name(&ibdev->dev),
 663                                 &vaf);
 664         } else if (ibdev) {
 665                 printk(KERN_DEBUG "%s: %pV", dev_name(&ibdev->dev), &vaf);
 666         } else {
 667                 printk(KERN_DEBUG "(NULL ib_device): %pV", &vaf);
 668         }
 669
 670         va_end(args);
 671 }
 672 EXPORT_SYMBOL(__dynamic_ibdev_dbg);
 673
 674 #endif
 675
 676 #define DDEBUG_STRING_SIZE 1024
 677 static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
 678
 679 static __init int ddebug_setup_query(char *str)
 680 {
 681         if (strlen(str) >= DDEBUG_STRING_SIZE) {
 682                 pr_warn("ddebug boot param string too large\n");
 683                 return 0;
 684         }
 685         strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
 686         return 1;
 687 }
 688
 689 __setup("ddebug_query=", ddebug_setup_query);
 690
 691 /*
 692  * File_ops->write method for <debugfs>/dynamic_debug/control.  Gathers the
 693  * command text from userspace, parses and executes it.
 694  */
 695 #define USER_BUF_PAGE 4096
 696 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
 697                                   size_t len, loff_t *offp)
 698 {
 699         char *tmpbuf;
 700         int ret;
 701
 702         if (len == 0)
 703                 return 0;
 704         if (len > USER_BUF_PAGE - 1) {
 705                 pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
 706                 return -E2BIG;
 707         }
 708         tmpbuf = memdup_user_nul(ubuf, len);
 709         if (IS_ERR(tmpbuf))
 710                 return PTR_ERR(tmpbuf);
 711         vpr_info("read %d bytes from userspace\n", (int)len);
 712
 713         ret = ddebug_exec_queries(tmpbuf, NULL);
 714         kfree(tmpbuf);
 715         if (ret < 0)
 716                 return ret;
 717
 718         *offp += len;
 719         return len;
 720 }
 721
 722 /*
 723  * Set the iterator to point to the first _ddebug object
 724  * and return a pointer to that first object.  Returns
 725  * NULL if there are no _ddebugs at all.
 726  */
 727 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
 728 {
 729         if (list_empty(&ddebug_tables)) {
 730                 iter->table = NULL;
 731                 iter->idx = 0;
 732                 return NULL;
 733         }
 734         iter->table = list_entry(ddebug_tables.next,
 735                                  struct ddebug_table, link);
 736         iter->idx = 0;
 737         return &iter->table->ddebugs[iter->idx];
 738 }
 739
 740 /*
 741  * Advance the iterator to point to the next _ddebug
 742  * object from the one the iterator currently points at,
 743  * and returns a pointer to the new _ddebug.  Returns
 744  * NULL if the iterator has seen all the _ddebugs.
 745  */
 746 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
 747 {
 748         if (iter->table == NULL)
 749                 return NULL;
 750         if (++iter->idx == iter->table->num_ddebugs) {
 751                 /* iterate to next table */
 752                 iter->idx = 0;
 753                 if (list_is_last(&iter->table->link, &ddebug_tables)) {
 754                         iter->table = NULL;
 755                         return NULL;
 756                 }
 757                 iter->table = list_entry(iter->table->link.next,
 758                                          struct ddebug_table, link);
 759         }
 760         return &iter->table->ddebugs[iter->idx];
 761 }
 762
 763 /*
 764  * Seq_ops start method.  Called at the start of every
 765  * read() call from userspace.  Takes the ddebug_lock and
 766  * seeks the seq_file's iterator to the given position.
 767  */
 768 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
 769 {
 770         struct ddebug_iter *iter = m->private;
 771         struct _ddebug *dp;
 772         int n = *pos;
 773
 774         vpr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
 775
 776         mutex_lock(&ddebug_lock);
 777
 778         if (!n)
 779                 return SEQ_START_TOKEN;
 780         if (n < 0)
 781                 return NULL;
 782         dp = ddebug_iter_first(iter);
 783         while (dp != NULL && --n > 0)
 784                 dp = ddebug_iter_next(iter);
 785         return dp;
 786 }
 787
 788 /*
 789  * Seq_ops next method.  Called several times within a read()
 790  * call from userspace, with ddebug_lock held.  Walks to the
 791  * next _ddebug object with a special case for the header line.
 792  */
 793 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
 794 {
 795         struct ddebug_iter *iter = m->private;
 796         struct _ddebug *dp;
 797
 798         vpr_info("called m=%p p=%p *pos=%lld\n",
 799                  m, p, (unsigned long long)*pos);
 800
 801         if (p == SEQ_START_TOKEN)
 802                 dp = ddebug_iter_first(iter);
 803         else
 804                 dp = ddebug_iter_next(iter);
 805         ++*pos;
 806         return dp;
 807 }
 808
 809 /*
 810  * Seq_ops show method.  Called several times within a read()
 811  * call from userspace, with ddebug_lock held.  Formats the
 812  * current _ddebug as a single human-readable line, with a
 813  * special case for the header line.
 814  */
 815 static int ddebug_proc_show(struct seq_file *m, void *p)
 816 {
 817         struct ddebug_iter *iter = m->private;
 818         struct _ddebug *dp = p;
 819         char flagsbuf[10];
 820
 821         vpr_info("called m=%p p=%p\n", m, p);
 822
 823         if (p == SEQ_START_TOKEN) {
 824                 seq_puts(m,
 825                          "# filename:lineno [module]function flags format\n");
 826                 return 0;
 827         }
 828
 829         seq_printf(m, "%s:%u [%s]%s =%s \"",
 830                    trim_prefix(dp->filename), dp->lineno,
 831                    iter->table->mod_name, dp->function,
 832                    ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
 833         seq_escape(m, dp->format, "\t\r\n\"");
 834         seq_puts(m, "\"\n");
 835
 836         return 0;
 837 }
 838
 839 /*
 840  * Seq_ops stop method.  Called at the end of each read()
 841  * call from userspace.  Drops ddebug_lock.
 842  */
 843 static void ddebug_proc_stop(struct seq_file *m, void *p)
 844 {
 845         vpr_info("called m=%p p=%p\n", m, p);
 846         mutex_unlock(&ddebug_lock);
 847 }
 848
 849 static const struct seq_operations ddebug_proc_seqops = {
 850         .start = ddebug_proc_start,
 851         .next = ddebug_proc_next,
 852         .show = ddebug_proc_show,
 853         .stop = ddebug_proc_stop
 854 };
 855
 856 /*
 857  * File_ops->open method for <debugfs>/dynamic_debug/control.  Does
 858  * the seq_file setup dance, and also creates an iterator to walk the
 859  * _ddebugs.  Note that we create a seq_file always, even for O_WRONLY
 860  * files where it's not needed, as doing so simplifies the ->release
 861  * method.
 862  */
 863 static int ddebug_proc_open(struct inode *inode, struct file *file)
 864 {
 865         vpr_info("called\n");
 866         return seq_open_private(file, &ddebug_proc_seqops,
 867                                 sizeof(struct ddebug_iter));
 868 }
 869
 870 static const struct file_operations ddebug_proc_fops = {
 871         .owner = THIS_MODULE,
 872         .open = ddebug_proc_open,
 873         .read = seq_read,
 874         .llseek = seq_lseek,
 875         .release = seq_release_private,
 876         .write = ddebug_proc_write
 877 };
 878
 879 static const struct proc_ops proc_fops = {
 880         .proc_open = ddebug_proc_open,
 881         .proc_read = seq_read,
 882         .proc_lseek = seq_lseek,
 883         .proc_release = seq_release_private,
 884         .proc_write = ddebug_proc_write
 885 };
 886
 887 /*
 888  * Allocate a new ddebug_table for the given module
 889  * and add it to the global list.
 890  */
 891 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 892                              const char *name)
 893 {
 894         struct ddebug_table *dt;
 895
 896         dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 897         if (dt == NULL) {
 898                 pr_err("error adding module: %s\n", name);
 899                 return -ENOMEM;
 900         }
 901         /*
 902          * For built-in modules, name lives in .rodata and is
 903          * immortal. For loaded modules, name points at the name[]
 904          * member of struct module, which lives at least as long as
 905          * this struct ddebug_table.
 906          */
 907         dt->mod_name = name;
 908         dt->num_ddebugs = n;
 909         dt->ddebugs = tab;
 910
 911         mutex_lock(&ddebug_lock);
 912         list_add_tail(&dt->link, &ddebug_tables);
 913         mutex_unlock(&ddebug_lock);
 914
 915         vpr_info("%u debug prints in module %s\n", n, dt->mod_name);
 916         return 0;
 917 }
 918
 919 /* helper for ddebug_dyndbg_(boot|module)_param_cb */
 920 static int ddebug_dyndbg_param_cb(char *param, char *val,
 921                                 const char *modname, int on_err)
 922 {
 923         char *sep;
 924
 925         sep = strchr(param, '.');
 926         if (sep) {
 927                 /* needed only for ddebug_dyndbg_boot_param_cb */
 928                 *sep = '\0';
 929                 modname = param;
 930                 param = sep + 1;
 931         }
 932         if (strcmp(param, "dyndbg"))
 933                 return on_err; /* determined by caller */
 934
 935         ddebug_exec_queries((val ? val : "+p"), modname);
 936
 937         return 0; /* query failure shouldnt stop module load */
 938 }
 939
 940 /* handle both dyndbg and $module.dyndbg params at boot */
 941 static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
 942                                 const char *unused, void *arg)
 943 {
 944         vpr_info("%s=\"%s\"\n", param, val);
 945         return ddebug_dyndbg_param_cb(param, val, NULL, 0);
 946 }
 947
 948 /*
 949  * modprobe foo finds foo.params in boot-args, strips "foo.", and
 950  * passes them to load_module().  This callback gets unknown params,
 951  * processes dyndbg params, rejects others.
 952  */
 953 int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *module)
 954 {
 955         vpr_info("module: %s %s=\"%s\"\n", module, param, val);
 956         return ddebug_dyndbg_param_cb(param, val, module, -ENOENT);
 957 }
 958
 959 static void ddebug_table_free(struct ddebug_table *dt)
 960 {
 961         list_del_init(&dt->link);
 962         kfree(dt);
 963 }
 964
 965 /*
 966  * Called in response to a module being unloaded.  Removes
 967  * any ddebug_table's which point at the module.
 968  */
 969 int ddebug_remove_module(const char *mod_name)
 970 {
 971         struct ddebug_table *dt, *nextdt;
 972         int ret = -ENOENT;
 973
 974         vpr_info("removing module \"%s\"\n", mod_name);
 975
 976         mutex_lock(&ddebug_lock);
 977         list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
 978                 if (dt->mod_name == mod_name) {
 979                         ddebug_table_free(dt);
 980                         ret = 0;
 981                         break;
 982                 }
 983         }
 984         mutex_unlock(&ddebug_lock);
 985         return ret;
 986 }
 987
 988 static void ddebug_remove_all_tables(void)
 989 {
 990         mutex_lock(&ddebug_lock);
 991         while (!list_empty(&ddebug_tables)) {
 992                 struct ddebug_table *dt = list_entry(ddebug_tables.next,
 993                                                       struct ddebug_table,
 994                                                       link);
 995                 ddebug_table_free(dt);
 996         }
 997         mutex_unlock(&ddebug_lock);
 998 }
 999
1000 static __initdata int ddebug_init_success;
1001
1002 static int __init dynamic_debug_init_control(void)
1003 {
1004         struct proc_dir_entry *procfs_dir;
1005         struct dentry *debugfs_dir;
1006
1007         if (!ddebug_init_success)
1008                 return -ENODEV;
1009
1010         /* Create the control file in debugfs if it is enabled */
1011         if (debugfs_initialized()) {
1012                 debugfs_dir = debugfs_create_dir("dynamic_debug", NULL);
1013                 debugfs_create_file("control", 0644, debugfs_dir, NULL,
1014                                     &ddebug_proc_fops);
1015         }
1016
1017         /* Also create the control file in procfs */
1018         procfs_dir = proc_mkdir("dynamic_debug", NULL);
1019         if (procfs_dir)
1020                 proc_create("control", 0644, procfs_dir, &proc_fops);
1021
1022         return 0;
1023 }
1024
1025 static int __init dynamic_debug_init(void)
1026 {
1027         struct _ddebug *iter, *iter_start;
1028         const char *modname = NULL;
1029         char *cmdline;
1030         int ret = 0;
1031         int n = 0, entries = 0, modct = 0;
1032         int verbose_bytes = 0;
1033
1034         if (&__start___verbose == &__stop___verbose) {
1035                 pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
1036                 return 1;
1037         }
1038         iter = __start___verbose;
1039         modname = iter->modname;
1040         iter_start = iter;
1041         for (; iter < __stop___verbose; iter++) {
1042                 entries++;
1043                 verbose_bytes += strlen(iter->modname) + strlen(iter->function)
1044                         + strlen(iter->filename) + strlen(iter->format);
1045
1046                 if (strcmp(modname, iter->modname)) {
1047                         modct++;
1048                         ret = ddebug_add_module(iter_start, n, modname);
1049                         if (ret)
1050                                 goto out_err;
1051                         n = 0;
1052                         modname = iter->modname;
1053                         iter_start = iter;
1054                 }
1055                 n++;
1056         }
1057         ret = ddebug_add_module(iter_start, n, modname);
1058         if (ret)
1059                 goto out_err;
1060
1061         ddebug_init_success = 1;
1062         vpr_info("%d modules, %d entries and %d bytes in ddebug tables, %d bytes in (readonly) verbose section\n",
1063                  modct, entries, (int)(modct * sizeof(struct ddebug_table)),
1064                  verbose_bytes + (int)(__stop___verbose - __start___verbose));
1065
1066         /* apply ddebug_query boot param, dont unload tables on err */
1067         if (ddebug_setup_string[0] != '\0') {
1068                 pr_warn("ddebug_query param name is deprecated, change it to dyndbg\n");
1069                 ret = ddebug_exec_queries(ddebug_setup_string, NULL);
1070                 if (ret < 0)
1071                         pr_warn("Invalid ddebug boot param %s\n",
1072                                 ddebug_setup_string);
1073                 else
1074                         pr_info("%d changes by ddebug_query\n", ret);
1075         }
1076         /* now that ddebug tables are loaded, process all boot args
1077          * again to find and activate queries given in dyndbg params.
1078          * While this has already been done for known boot params, it
1079          * ignored the unknown ones (dyndbg in particular).  Reusing
1080          * parse_args avoids ad-hoc parsing.  This will also attempt
1081          * to activate queries for not-yet-loaded modules, which is
1082          * slightly noisy if verbose, but harmless.
1083          */
1084         cmdline = kstrdup(saved_command_line, GFP_KERNEL);
1085         parse_args("dyndbg params", cmdline, NULL,
1086                    0, 0, 0, NULL, &ddebug_dyndbg_boot_param_cb);
1087         kfree(cmdline);
1088         return 0;
1089
1090 out_err:
1091         ddebug_remove_all_tables();
1092         return 0;
1093 }
1094 /* Allow early initialization for boot messages via boot param */
1095 early_initcall(dynamic_debug_init);
1096
1097 /* Debugfs setup must be done later */
1098 fs_initcall(dynamic_debug_init_control);