dynamic_debug.c 21 KB

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  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. */
  12. #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
  13. #include <linux/kernel.h>
  14. #include <linux/module.h>
  15. #include <linux/moduleparam.h>
  16. #include <linux/kallsyms.h>
  17. #include <linux/types.h>
  18. #include <linux/mutex.h>
  19. #include <linux/proc_fs.h>
  20. #include <linux/seq_file.h>
  21. #include <linux/list.h>
  22. #include <linux/sysctl.h>
  23. #include <linux/ctype.h>
  24. #include <linux/string.h>
  25. #include <linux/uaccess.h>
  26. #include <linux/dynamic_debug.h>
  27. #include <linux/debugfs.h>
  28. #include <linux/slab.h>
  29. #include <linux/jump_label.h>
  30. #include <linux/hardirq.h>
  31. #include <linux/sched.h>
  32. #include <linux/device.h>
  33. #include <linux/netdevice.h>
  34. extern struct _ddebug __start___verbose[];
  35. extern struct _ddebug __stop___verbose[];
  36. struct ddebug_table {
  37. struct list_head link;
  38. char *mod_name;
  39. unsigned int num_ddebugs;
  40. struct _ddebug *ddebugs;
  41. };
  42. struct ddebug_query {
  43. const char *filename;
  44. const char *module;
  45. const char *function;
  46. const char *format;
  47. unsigned int first_lineno, last_lineno;
  48. };
  49. struct ddebug_iter {
  50. struct ddebug_table *table;
  51. unsigned int idx;
  52. };
  53. static DEFINE_MUTEX(ddebug_lock);
  54. static LIST_HEAD(ddebug_tables);
  55. static int verbose = 0;
  56. module_param(verbose, int, 0644);
  57. /* Return the last part of a pathname */
  58. static inline const char *basename(const char *path)
  59. {
  60. const char *tail = strrchr(path, '/');
  61. return tail ? tail+1 : path;
  62. }
  63. static struct { unsigned flag:8; char opt_char; } opt_array[] = {
  64. { _DPRINTK_FLAGS_PRINT, 'p' },
  65. { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
  66. { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
  67. { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
  68. { _DPRINTK_FLAGS_INCL_TID, 't' },
  69. { _DPRINTK_FLAGS_NONE, '_' },
  70. };
  71. /* format a string into buf[] which describes the _ddebug's flags */
  72. static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
  73. size_t maxlen)
  74. {
  75. char *p = buf;
  76. int i;
  77. BUG_ON(maxlen < 6);
  78. for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
  79. if (dp->flags & opt_array[i].flag)
  80. *p++ = opt_array[i].opt_char;
  81. if (p == buf)
  82. *p++ = '_';
  83. *p = '\0';
  84. return buf;
  85. }
  86. /*
  87. * Search the tables for _ddebug's which match the given
  88. * `query' and apply the `flags' and `mask' to them. Tells
  89. * the user which ddebug's were changed, or whether none
  90. * were matched.
  91. */
  92. static void ddebug_change(const struct ddebug_query *query,
  93. unsigned int flags, unsigned int mask)
  94. {
  95. int i;
  96. struct ddebug_table *dt;
  97. unsigned int newflags;
  98. unsigned int nfound = 0;
  99. char flagbuf[10];
  100. /* search for matching ddebugs */
  101. mutex_lock(&ddebug_lock);
  102. list_for_each_entry(dt, &ddebug_tables, link) {
  103. /* match against the module name */
  104. if (query->module && strcmp(query->module, dt->mod_name))
  105. continue;
  106. for (i = 0 ; i < dt->num_ddebugs ; i++) {
  107. struct _ddebug *dp = &dt->ddebugs[i];
  108. /* match against the source filename */
  109. if (query->filename &&
  110. strcmp(query->filename, dp->filename) &&
  111. strcmp(query->filename, basename(dp->filename)))
  112. continue;
  113. /* match against the function */
  114. if (query->function &&
  115. strcmp(query->function, dp->function))
  116. continue;
  117. /* match against the format */
  118. if (query->format &&
  119. !strstr(dp->format, query->format))
  120. continue;
  121. /* match against the line number range */
  122. if (query->first_lineno &&
  123. dp->lineno < query->first_lineno)
  124. continue;
  125. if (query->last_lineno &&
  126. dp->lineno > query->last_lineno)
  127. continue;
  128. nfound++;
  129. newflags = (dp->flags & mask) | flags;
  130. if (newflags == dp->flags)
  131. continue;
  132. dp->flags = newflags;
  133. if (verbose)
  134. pr_info("changed %s:%d [%s]%s =%s\n",
  135. dp->filename, dp->lineno,
  136. dt->mod_name, dp->function,
  137. ddebug_describe_flags(dp, flagbuf,
  138. sizeof(flagbuf)));
  139. }
  140. }
  141. mutex_unlock(&ddebug_lock);
  142. if (!nfound && verbose)
  143. pr_info("no matches for query\n");
  144. }
  145. /*
  146. * Split the buffer `buf' into space-separated words.
  147. * Handles simple " and ' quoting, i.e. without nested,
  148. * embedded or escaped \". Return the number of words
  149. * or <0 on error.
  150. */
  151. static int ddebug_tokenize(char *buf, char *words[], int maxwords)
  152. {
  153. int nwords = 0;
  154. while (*buf) {
  155. char *end;
  156. /* Skip leading whitespace */
  157. buf = skip_spaces(buf);
  158. if (!*buf)
  159. break; /* oh, it was trailing whitespace */
  160. /* find `end' of word, whitespace separated or quoted */
  161. if (*buf == '"' || *buf == '\'') {
  162. int quote = *buf++;
  163. for (end = buf ; *end && *end != quote ; end++)
  164. ;
  165. if (!*end)
  166. return -EINVAL; /* unclosed quote */
  167. } else {
  168. for (end = buf ; *end && !isspace(*end) ; end++)
  169. ;
  170. BUG_ON(end == buf);
  171. }
  172. /* `buf' is start of word, `end' is one past its end */
  173. if (nwords == maxwords)
  174. return -EINVAL; /* ran out of words[] before bytes */
  175. if (*end)
  176. *end++ = '\0'; /* terminate the word */
  177. words[nwords++] = buf;
  178. buf = end;
  179. }
  180. if (verbose) {
  181. int i;
  182. pr_info("split into words:");
  183. for (i = 0 ; i < nwords ; i++)
  184. pr_cont(" \"%s\"", words[i]);
  185. pr_cont("\n");
  186. }
  187. return nwords;
  188. }
  189. /*
  190. * Parse a single line number. Note that the empty string ""
  191. * is treated as a special case and converted to zero, which
  192. * is later treated as a "don't care" value.
  193. */
  194. static inline int parse_lineno(const char *str, unsigned int *val)
  195. {
  196. char *end = NULL;
  197. BUG_ON(str == NULL);
  198. if (*str == '\0') {
  199. *val = 0;
  200. return 0;
  201. }
  202. *val = simple_strtoul(str, &end, 10);
  203. return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
  204. }
  205. /*
  206. * Undo octal escaping in a string, inplace. This is useful to
  207. * allow the user to express a query which matches a format
  208. * containing embedded spaces.
  209. */
  210. #define isodigit(c) ((c) >= '0' && (c) <= '7')
  211. static char *unescape(char *str)
  212. {
  213. char *in = str;
  214. char *out = str;
  215. while (*in) {
  216. if (*in == '\\') {
  217. if (in[1] == '\\') {
  218. *out++ = '\\';
  219. in += 2;
  220. continue;
  221. } else if (in[1] == 't') {
  222. *out++ = '\t';
  223. in += 2;
  224. continue;
  225. } else if (in[1] == 'n') {
  226. *out++ = '\n';
  227. in += 2;
  228. continue;
  229. } else if (isodigit(in[1]) &&
  230. isodigit(in[2]) &&
  231. isodigit(in[3])) {
  232. *out++ = ((in[1] - '0')<<6) |
  233. ((in[2] - '0')<<3) |
  234. (in[3] - '0');
  235. in += 4;
  236. continue;
  237. }
  238. }
  239. *out++ = *in++;
  240. }
  241. *out = '\0';
  242. return str;
  243. }
  244. static int check_set(const char **dest, char *src, char *name)
  245. {
  246. int rc = 0;
  247. if (*dest) {
  248. rc = -EINVAL;
  249. pr_err("match-spec:%s val:%s overridden by %s",
  250. name, *dest, src);
  251. }
  252. *dest = src;
  253. return rc;
  254. }
  255. /*
  256. * Parse words[] as a ddebug query specification, which is a series
  257. * of (keyword, value) pairs chosen from these possibilities:
  258. *
  259. * func <function-name>
  260. * file <full-pathname>
  261. * file <base-filename>
  262. * module <module-name>
  263. * format <escaped-string-to-find-in-format>
  264. * line <lineno>
  265. * line <first-lineno>-<last-lineno> // where either may be empty
  266. *
  267. * Only 1 of each type is allowed.
  268. * Returns 0 on success, <0 on error.
  269. */
  270. static int ddebug_parse_query(char *words[], int nwords,
  271. struct ddebug_query *query)
  272. {
  273. unsigned int i;
  274. int rc;
  275. /* check we have an even number of words */
  276. if (nwords % 2 != 0)
  277. return -EINVAL;
  278. memset(query, 0, sizeof(*query));
  279. for (i = 0 ; i < nwords ; i += 2) {
  280. if (!strcmp(words[i], "func"))
  281. rc = check_set(&query->function, words[i+1], "func");
  282. else if (!strcmp(words[i], "file"))
  283. rc = check_set(&query->filename, words[i+1], "file");
  284. else if (!strcmp(words[i], "module"))
  285. rc = check_set(&query->module, words[i+1], "module");
  286. else if (!strcmp(words[i], "format"))
  287. rc = check_set(&query->format, unescape(words[i+1]),
  288. "format");
  289. else if (!strcmp(words[i], "line")) {
  290. char *first = words[i+1];
  291. char *last = strchr(first, '-');
  292. if (query->first_lineno || query->last_lineno) {
  293. pr_err("match-spec:line given 2 times\n");
  294. return -EINVAL;
  295. }
  296. if (last)
  297. *last++ = '\0';
  298. if (parse_lineno(first, &query->first_lineno) < 0)
  299. return -EINVAL;
  300. if (last) {
  301. /* range <first>-<last> */
  302. if (parse_lineno(last, &query->last_lineno)
  303. < query->first_lineno) {
  304. pr_err("last-line < 1st-line\n");
  305. return -EINVAL;
  306. }
  307. } else {
  308. query->last_lineno = query->first_lineno;
  309. }
  310. } else {
  311. pr_err("unknown keyword \"%s\"\n", words[i]);
  312. return -EINVAL;
  313. }
  314. if (rc)
  315. return rc;
  316. }
  317. if (verbose)
  318. pr_info("q->function=\"%s\" q->filename=\"%s\" "
  319. "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
  320. query->function, query->filename,
  321. query->module, query->format, query->first_lineno,
  322. query->last_lineno);
  323. return 0;
  324. }
  325. /*
  326. * Parse `str' as a flags specification, format [-+=][p]+.
  327. * Sets up *maskp and *flagsp to be used when changing the
  328. * flags fields of matched _ddebug's. Returns 0 on success
  329. * or <0 on error.
  330. */
  331. static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
  332. unsigned int *maskp)
  333. {
  334. unsigned flags = 0;
  335. int op = '=', i;
  336. switch (*str) {
  337. case '+':
  338. case '-':
  339. case '=':
  340. op = *str++;
  341. break;
  342. default:
  343. return -EINVAL;
  344. }
  345. if (verbose)
  346. pr_info("op='%c'\n", op);
  347. for ( ; *str ; ++str) {
  348. for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
  349. if (*str == opt_array[i].opt_char) {
  350. flags |= opt_array[i].flag;
  351. break;
  352. }
  353. }
  354. if (i < 0)
  355. return -EINVAL;
  356. }
  357. if (verbose)
  358. pr_info("flags=0x%x\n", flags);
  359. /* calculate final *flagsp, *maskp according to mask and op */
  360. switch (op) {
  361. case '=':
  362. *maskp = 0;
  363. *flagsp = flags;
  364. break;
  365. case '+':
  366. *maskp = ~0U;
  367. *flagsp = flags;
  368. break;
  369. case '-':
  370. *maskp = ~flags;
  371. *flagsp = 0;
  372. break;
  373. }
  374. if (verbose)
  375. pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
  376. return 0;
  377. }
  378. static int ddebug_exec_query(char *query_string)
  379. {
  380. unsigned int flags = 0, mask = 0;
  381. struct ddebug_query query;
  382. #define MAXWORDS 9
  383. int nwords;
  384. char *words[MAXWORDS];
  385. nwords = ddebug_tokenize(query_string, words, MAXWORDS);
  386. if (nwords <= 0)
  387. return -EINVAL;
  388. if (ddebug_parse_query(words, nwords-1, &query))
  389. return -EINVAL;
  390. if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
  391. return -EINVAL;
  392. /* actually go and implement the change */
  393. ddebug_change(&query, flags, mask);
  394. return 0;
  395. }
  396. #define PREFIX_SIZE 64
  397. static int remaining(int wrote)
  398. {
  399. if (PREFIX_SIZE - wrote > 0)
  400. return PREFIX_SIZE - wrote;
  401. return 0;
  402. }
  403. static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
  404. {
  405. int pos_after_tid;
  406. int pos = 0;
  407. pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
  408. if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
  409. if (in_interrupt())
  410. pos += snprintf(buf + pos, remaining(pos), "%s ",
  411. "<intr>");
  412. else
  413. pos += snprintf(buf + pos, remaining(pos), "[%d] ",
  414. task_pid_vnr(current));
  415. }
  416. pos_after_tid = pos;
  417. if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
  418. pos += snprintf(buf + pos, remaining(pos), "%s:",
  419. desc->modname);
  420. if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
  421. pos += snprintf(buf + pos, remaining(pos), "%s:",
  422. desc->function);
  423. if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
  424. pos += snprintf(buf + pos, remaining(pos), "%d:",
  425. desc->lineno);
  426. if (pos - pos_after_tid)
  427. pos += snprintf(buf + pos, remaining(pos), " ");
  428. if (pos >= PREFIX_SIZE)
  429. buf[PREFIX_SIZE - 1] = '\0';
  430. return buf;
  431. }
  432. int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
  433. {
  434. va_list args;
  435. int res;
  436. struct va_format vaf;
  437. char buf[PREFIX_SIZE];
  438. BUG_ON(!descriptor);
  439. BUG_ON(!fmt);
  440. va_start(args, fmt);
  441. vaf.fmt = fmt;
  442. vaf.va = &args;
  443. res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
  444. va_end(args);
  445. return res;
  446. }
  447. EXPORT_SYMBOL(__dynamic_pr_debug);
  448. int __dynamic_dev_dbg(struct _ddebug *descriptor,
  449. const struct device *dev, const char *fmt, ...)
  450. {
  451. struct va_format vaf;
  452. va_list args;
  453. int res;
  454. char buf[PREFIX_SIZE];
  455. BUG_ON(!descriptor);
  456. BUG_ON(!fmt);
  457. va_start(args, fmt);
  458. vaf.fmt = fmt;
  459. vaf.va = &args;
  460. res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
  461. va_end(args);
  462. return res;
  463. }
  464. EXPORT_SYMBOL(__dynamic_dev_dbg);
  465. #ifdef CONFIG_NET
  466. int __dynamic_netdev_dbg(struct _ddebug *descriptor,
  467. const struct net_device *dev, const char *fmt, ...)
  468. {
  469. struct va_format vaf;
  470. va_list args;
  471. int res;
  472. char buf[PREFIX_SIZE];
  473. BUG_ON(!descriptor);
  474. BUG_ON(!fmt);
  475. va_start(args, fmt);
  476. vaf.fmt = fmt;
  477. vaf.va = &args;
  478. res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
  479. va_end(args);
  480. return res;
  481. }
  482. EXPORT_SYMBOL(__dynamic_netdev_dbg);
  483. #endif
  484. #define DDEBUG_STRING_SIZE 1024
  485. static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
  486. static __init int ddebug_setup_query(char *str)
  487. {
  488. if (strlen(str) >= DDEBUG_STRING_SIZE) {
  489. pr_warn("ddebug boot param string too large\n");
  490. return 0;
  491. }
  492. strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
  493. return 1;
  494. }
  495. __setup("ddebug_query=", ddebug_setup_query);
  496. /*
  497. * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
  498. * command text from userspace, parses and executes it.
  499. */
  500. static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
  501. size_t len, loff_t *offp)
  502. {
  503. char tmpbuf[256];
  504. int ret;
  505. if (len == 0)
  506. return 0;
  507. /* we don't check *offp -- multiple writes() are allowed */
  508. if (len > sizeof(tmpbuf)-1)
  509. return -E2BIG;
  510. if (copy_from_user(tmpbuf, ubuf, len))
  511. return -EFAULT;
  512. tmpbuf[len] = '\0';
  513. if (verbose)
  514. pr_info("read %d bytes from userspace\n", (int)len);
  515. ret = ddebug_exec_query(tmpbuf);
  516. if (ret)
  517. return ret;
  518. *offp += len;
  519. return len;
  520. }
  521. /*
  522. * Set the iterator to point to the first _ddebug object
  523. * and return a pointer to that first object. Returns
  524. * NULL if there are no _ddebugs at all.
  525. */
  526. static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
  527. {
  528. if (list_empty(&ddebug_tables)) {
  529. iter->table = NULL;
  530. iter->idx = 0;
  531. return NULL;
  532. }
  533. iter->table = list_entry(ddebug_tables.next,
  534. struct ddebug_table, link);
  535. iter->idx = 0;
  536. return &iter->table->ddebugs[iter->idx];
  537. }
  538. /*
  539. * Advance the iterator to point to the next _ddebug
  540. * object from the one the iterator currently points at,
  541. * and returns a pointer to the new _ddebug. Returns
  542. * NULL if the iterator has seen all the _ddebugs.
  543. */
  544. static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
  545. {
  546. if (iter->table == NULL)
  547. return NULL;
  548. if (++iter->idx == iter->table->num_ddebugs) {
  549. /* iterate to next table */
  550. iter->idx = 0;
  551. if (list_is_last(&iter->table->link, &ddebug_tables)) {
  552. iter->table = NULL;
  553. return NULL;
  554. }
  555. iter->table = list_entry(iter->table->link.next,
  556. struct ddebug_table, link);
  557. }
  558. return &iter->table->ddebugs[iter->idx];
  559. }
  560. /*
  561. * Seq_ops start method. Called at the start of every
  562. * read() call from userspace. Takes the ddebug_lock and
  563. * seeks the seq_file's iterator to the given position.
  564. */
  565. static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
  566. {
  567. struct ddebug_iter *iter = m->private;
  568. struct _ddebug *dp;
  569. int n = *pos;
  570. if (verbose)
  571. pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
  572. mutex_lock(&ddebug_lock);
  573. if (!n)
  574. return SEQ_START_TOKEN;
  575. if (n < 0)
  576. return NULL;
  577. dp = ddebug_iter_first(iter);
  578. while (dp != NULL && --n > 0)
  579. dp = ddebug_iter_next(iter);
  580. return dp;
  581. }
  582. /*
  583. * Seq_ops next method. Called several times within a read()
  584. * call from userspace, with ddebug_lock held. Walks to the
  585. * next _ddebug object with a special case for the header line.
  586. */
  587. static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
  588. {
  589. struct ddebug_iter *iter = m->private;
  590. struct _ddebug *dp;
  591. if (verbose)
  592. pr_info("called m=%p p=%p *pos=%lld\n",
  593. m, p, (unsigned long long)*pos);
  594. if (p == SEQ_START_TOKEN)
  595. dp = ddebug_iter_first(iter);
  596. else
  597. dp = ddebug_iter_next(iter);
  598. ++*pos;
  599. return dp;
  600. }
  601. /*
  602. * Seq_ops show method. Called several times within a read()
  603. * call from userspace, with ddebug_lock held. Formats the
  604. * current _ddebug as a single human-readable line, with a
  605. * special case for the header line.
  606. */
  607. static int ddebug_proc_show(struct seq_file *m, void *p)
  608. {
  609. struct ddebug_iter *iter = m->private;
  610. struct _ddebug *dp = p;
  611. char flagsbuf[10];
  612. if (verbose)
  613. pr_info("called m=%p p=%p\n", m, p);
  614. if (p == SEQ_START_TOKEN) {
  615. seq_puts(m,
  616. "# filename:lineno [module]function flags format\n");
  617. return 0;
  618. }
  619. seq_printf(m, "%s:%u [%s]%s =%s \"",
  620. dp->filename, dp->lineno,
  621. iter->table->mod_name, dp->function,
  622. ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
  623. seq_escape(m, dp->format, "\t\r\n\"");
  624. seq_puts(m, "\"\n");
  625. return 0;
  626. }
  627. /*
  628. * Seq_ops stop method. Called at the end of each read()
  629. * call from userspace. Drops ddebug_lock.
  630. */
  631. static void ddebug_proc_stop(struct seq_file *m, void *p)
  632. {
  633. if (verbose)
  634. pr_info("called m=%p p=%p\n", m, p);
  635. mutex_unlock(&ddebug_lock);
  636. }
  637. static const struct seq_operations ddebug_proc_seqops = {
  638. .start = ddebug_proc_start,
  639. .next = ddebug_proc_next,
  640. .show = ddebug_proc_show,
  641. .stop = ddebug_proc_stop
  642. };
  643. /*
  644. * File_ops->open method for <debugfs>/dynamic_debug/control. Does
  645. * the seq_file setup dance, and also creates an iterator to walk the
  646. * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
  647. * files where it's not needed, as doing so simplifies the ->release
  648. * method.
  649. */
  650. static int ddebug_proc_open(struct inode *inode, struct file *file)
  651. {
  652. struct ddebug_iter *iter;
  653. int err;
  654. if (verbose)
  655. pr_info("called\n");
  656. iter = kzalloc(sizeof(*iter), GFP_KERNEL);
  657. if (iter == NULL)
  658. return -ENOMEM;
  659. err = seq_open(file, &ddebug_proc_seqops);
  660. if (err) {
  661. kfree(iter);
  662. return err;
  663. }
  664. ((struct seq_file *) file->private_data)->private = iter;
  665. return 0;
  666. }
  667. static const struct file_operations ddebug_proc_fops = {
  668. .owner = THIS_MODULE,
  669. .open = ddebug_proc_open,
  670. .read = seq_read,
  671. .llseek = seq_lseek,
  672. .release = seq_release_private,
  673. .write = ddebug_proc_write
  674. };
  675. /*
  676. * Allocate a new ddebug_table for the given module
  677. * and add it to the global list.
  678. */
  679. int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  680. const char *name)
  681. {
  682. struct ddebug_table *dt;
  683. char *new_name;
  684. dt = kzalloc(sizeof(*dt), GFP_KERNEL);
  685. if (dt == NULL)
  686. return -ENOMEM;
  687. new_name = kstrdup(name, GFP_KERNEL);
  688. if (new_name == NULL) {
  689. kfree(dt);
  690. return -ENOMEM;
  691. }
  692. dt->mod_name = new_name;
  693. dt->num_ddebugs = n;
  694. dt->ddebugs = tab;
  695. mutex_lock(&ddebug_lock);
  696. list_add_tail(&dt->link, &ddebug_tables);
  697. mutex_unlock(&ddebug_lock);
  698. if (verbose)
  699. pr_info("%u debug prints in module %s\n", n, dt->mod_name);
  700. return 0;
  701. }
  702. EXPORT_SYMBOL_GPL(ddebug_add_module);
  703. static void ddebug_table_free(struct ddebug_table *dt)
  704. {
  705. list_del_init(&dt->link);
  706. kfree(dt->mod_name);
  707. kfree(dt);
  708. }
  709. /*
  710. * Called in response to a module being unloaded. Removes
  711. * any ddebug_table's which point at the module.
  712. */
  713. int ddebug_remove_module(const char *mod_name)
  714. {
  715. struct ddebug_table *dt, *nextdt;
  716. int ret = -ENOENT;
  717. if (verbose)
  718. pr_info("removing module \"%s\"\n", mod_name);
  719. mutex_lock(&ddebug_lock);
  720. list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
  721. if (!strcmp(dt->mod_name, mod_name)) {
  722. ddebug_table_free(dt);
  723. ret = 0;
  724. }
  725. }
  726. mutex_unlock(&ddebug_lock);
  727. return ret;
  728. }
  729. EXPORT_SYMBOL_GPL(ddebug_remove_module);
  730. static void ddebug_remove_all_tables(void)
  731. {
  732. mutex_lock(&ddebug_lock);
  733. while (!list_empty(&ddebug_tables)) {
  734. struct ddebug_table *dt = list_entry(ddebug_tables.next,
  735. struct ddebug_table,
  736. link);
  737. ddebug_table_free(dt);
  738. }
  739. mutex_unlock(&ddebug_lock);
  740. }
  741. static __initdata int ddebug_init_success;
  742. static int __init dynamic_debug_init_debugfs(void)
  743. {
  744. struct dentry *dir, *file;
  745. if (!ddebug_init_success)
  746. return -ENODEV;
  747. dir = debugfs_create_dir("dynamic_debug", NULL);
  748. if (!dir)
  749. return -ENOMEM;
  750. file = debugfs_create_file("control", 0644, dir, NULL,
  751. &ddebug_proc_fops);
  752. if (!file) {
  753. debugfs_remove(dir);
  754. return -ENOMEM;
  755. }
  756. return 0;
  757. }
  758. static int __init dynamic_debug_init(void)
  759. {
  760. struct _ddebug *iter, *iter_start;
  761. const char *modname = NULL;
  762. int ret = 0;
  763. int n = 0;
  764. if (__start___verbose != __stop___verbose) {
  765. iter = __start___verbose;
  766. modname = iter->modname;
  767. iter_start = iter;
  768. for (; iter < __stop___verbose; iter++) {
  769. if (strcmp(modname, iter->modname)) {
  770. ret = ddebug_add_module(iter_start, n, modname);
  771. if (ret)
  772. goto out_free;
  773. n = 0;
  774. modname = iter->modname;
  775. iter_start = iter;
  776. }
  777. n++;
  778. }
  779. ret = ddebug_add_module(iter_start, n, modname);
  780. }
  781. /* ddebug_query boot param got passed -> set it up */
  782. if (ddebug_setup_string[0] != '\0') {
  783. ret = ddebug_exec_query(ddebug_setup_string);
  784. if (ret)
  785. pr_warn("Invalid ddebug boot param %s",
  786. ddebug_setup_string);
  787. else
  788. pr_info("ddebug initialized with string %s",
  789. ddebug_setup_string);
  790. }
  791. out_free:
  792. if (ret)
  793. ddebug_remove_all_tables();
  794. else
  795. ddebug_init_success = 1;
  796. return 0;
  797. }
  798. /* Allow early initialization for boot messages via boot param */
  799. arch_initcall(dynamic_debug_init);
  800. /* Debugfs setup must be done later */
  801. module_init(dynamic_debug_init_debugfs);