dynamic_debug.c 20 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. };
  70. /* format a string into buf[] which describes the _ddebug's flags */
  71. static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
  72. size_t maxlen)
  73. {
  74. char *p = buf;
  75. int i;
  76. BUG_ON(maxlen < 4);
  77. for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
  78. if (dp->flags & opt_array[i].flag)
  79. *p++ = opt_array[i].opt_char;
  80. if (p == buf)
  81. *p++ = '-';
  82. *p = '\0';
  83. return buf;
  84. }
  85. /*
  86. * Search the tables for _ddebug's which match the given
  87. * `query' and apply the `flags' and `mask' to them. Tells
  88. * the user which ddebug's were changed, or whether none
  89. * were matched.
  90. */
  91. static void ddebug_change(const struct ddebug_query *query,
  92. unsigned int flags, unsigned int mask)
  93. {
  94. int i;
  95. struct ddebug_table *dt;
  96. unsigned int newflags;
  97. unsigned int nfound = 0;
  98. char flagbuf[8];
  99. /* search for matching ddebugs */
  100. mutex_lock(&ddebug_lock);
  101. list_for_each_entry(dt, &ddebug_tables, link) {
  102. /* match against the module name */
  103. if (query->module != NULL &&
  104. 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 != NULL &&
  110. strcmp(query->filename, dp->filename) &&
  111. strcmp(query->filename, basename(dp->filename)))
  112. continue;
  113. /* match against the function */
  114. if (query->function != NULL &&
  115. strcmp(query->function, dp->function))
  116. continue;
  117. /* match against the format */
  118. if (query->format != NULL &&
  119. strstr(dp->format, query->format) == NULL)
  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. /*
  245. * Parse words[] as a ddebug query specification, which is a series
  246. * of (keyword, value) pairs chosen from these possibilities:
  247. *
  248. * func <function-name>
  249. * file <full-pathname>
  250. * file <base-filename>
  251. * module <module-name>
  252. * format <escaped-string-to-find-in-format>
  253. * line <lineno>
  254. * line <first-lineno>-<last-lineno> // where either may be empty
  255. */
  256. static int ddebug_parse_query(char *words[], int nwords,
  257. struct ddebug_query *query)
  258. {
  259. unsigned int i;
  260. /* check we have an even number of words */
  261. if (nwords % 2 != 0)
  262. return -EINVAL;
  263. memset(query, 0, sizeof(*query));
  264. for (i = 0 ; i < nwords ; i += 2) {
  265. if (!strcmp(words[i], "func"))
  266. query->function = words[i+1];
  267. else if (!strcmp(words[i], "file"))
  268. query->filename = words[i+1];
  269. else if (!strcmp(words[i], "module"))
  270. query->module = words[i+1];
  271. else if (!strcmp(words[i], "format"))
  272. query->format = unescape(words[i+1]);
  273. else if (!strcmp(words[i], "line")) {
  274. char *first = words[i+1];
  275. char *last = strchr(first, '-');
  276. if (last)
  277. *last++ = '\0';
  278. if (parse_lineno(first, &query->first_lineno) < 0)
  279. return -EINVAL;
  280. if (last != NULL) {
  281. /* range <first>-<last> */
  282. if (parse_lineno(last, &query->last_lineno) < 0)
  283. return -EINVAL;
  284. } else {
  285. query->last_lineno = query->first_lineno;
  286. }
  287. } else {
  288. if (verbose)
  289. pr_err("unknown keyword \"%s\"\n", words[i]);
  290. return -EINVAL;
  291. }
  292. }
  293. if (verbose)
  294. pr_info("q->function=\"%s\" q->filename=\"%s\" "
  295. "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
  296. query->function, query->filename,
  297. query->module, query->format, query->first_lineno,
  298. query->last_lineno);
  299. return 0;
  300. }
  301. /*
  302. * Parse `str' as a flags specification, format [-+=][p]+.
  303. * Sets up *maskp and *flagsp to be used when changing the
  304. * flags fields of matched _ddebug's. Returns 0 on success
  305. * or <0 on error.
  306. */
  307. static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
  308. unsigned int *maskp)
  309. {
  310. unsigned flags = 0;
  311. int op = '=', i;
  312. switch (*str) {
  313. case '+':
  314. case '-':
  315. case '=':
  316. op = *str++;
  317. break;
  318. default:
  319. return -EINVAL;
  320. }
  321. if (verbose)
  322. pr_info("op='%c'\n", op);
  323. for ( ; *str ; ++str) {
  324. for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
  325. if (*str == opt_array[i].opt_char) {
  326. flags |= opt_array[i].flag;
  327. break;
  328. }
  329. }
  330. if (i < 0)
  331. return -EINVAL;
  332. }
  333. if (flags == 0)
  334. return -EINVAL;
  335. if (verbose)
  336. pr_info("flags=0x%x\n", flags);
  337. /* calculate final *flagsp, *maskp according to mask and op */
  338. switch (op) {
  339. case '=':
  340. *maskp = 0;
  341. *flagsp = flags;
  342. break;
  343. case '+':
  344. *maskp = ~0U;
  345. *flagsp = flags;
  346. break;
  347. case '-':
  348. *maskp = ~flags;
  349. *flagsp = 0;
  350. break;
  351. }
  352. if (verbose)
  353. pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
  354. return 0;
  355. }
  356. static int ddebug_exec_query(char *query_string)
  357. {
  358. unsigned int flags = 0, mask = 0;
  359. struct ddebug_query query;
  360. #define MAXWORDS 9
  361. int nwords;
  362. char *words[MAXWORDS];
  363. nwords = ddebug_tokenize(query_string, words, MAXWORDS);
  364. if (nwords <= 0)
  365. return -EINVAL;
  366. if (ddebug_parse_query(words, nwords-1, &query))
  367. return -EINVAL;
  368. if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
  369. return -EINVAL;
  370. /* actually go and implement the change */
  371. ddebug_change(&query, flags, mask);
  372. return 0;
  373. }
  374. #define PREFIX_SIZE 64
  375. static int remaining(int wrote)
  376. {
  377. if (PREFIX_SIZE - wrote > 0)
  378. return PREFIX_SIZE - wrote;
  379. return 0;
  380. }
  381. static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
  382. {
  383. int pos_after_tid;
  384. int pos = 0;
  385. pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
  386. if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
  387. if (in_interrupt())
  388. pos += snprintf(buf + pos, remaining(pos), "%s ",
  389. "<intr>");
  390. else
  391. pos += snprintf(buf + pos, remaining(pos), "[%d] ",
  392. task_pid_vnr(current));
  393. }
  394. pos_after_tid = pos;
  395. if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
  396. pos += snprintf(buf + pos, remaining(pos), "%s:",
  397. desc->modname);
  398. if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
  399. pos += snprintf(buf + pos, remaining(pos), "%s:",
  400. desc->function);
  401. if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
  402. pos += snprintf(buf + pos, remaining(pos), "%d:",
  403. desc->lineno);
  404. if (pos - pos_after_tid)
  405. pos += snprintf(buf + pos, remaining(pos), " ");
  406. if (pos >= PREFIX_SIZE)
  407. buf[PREFIX_SIZE - 1] = '\0';
  408. return buf;
  409. }
  410. int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
  411. {
  412. va_list args;
  413. int res;
  414. struct va_format vaf;
  415. char buf[PREFIX_SIZE];
  416. BUG_ON(!descriptor);
  417. BUG_ON(!fmt);
  418. va_start(args, fmt);
  419. vaf.fmt = fmt;
  420. vaf.va = &args;
  421. res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
  422. va_end(args);
  423. return res;
  424. }
  425. EXPORT_SYMBOL(__dynamic_pr_debug);
  426. int __dynamic_dev_dbg(struct _ddebug *descriptor,
  427. const struct device *dev, const char *fmt, ...)
  428. {
  429. struct va_format vaf;
  430. va_list args;
  431. int res;
  432. char buf[PREFIX_SIZE];
  433. BUG_ON(!descriptor);
  434. BUG_ON(!fmt);
  435. va_start(args, fmt);
  436. vaf.fmt = fmt;
  437. vaf.va = &args;
  438. res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
  439. va_end(args);
  440. return res;
  441. }
  442. EXPORT_SYMBOL(__dynamic_dev_dbg);
  443. #ifdef CONFIG_NET
  444. int __dynamic_netdev_dbg(struct _ddebug *descriptor,
  445. const struct net_device *dev, const char *fmt, ...)
  446. {
  447. struct va_format vaf;
  448. va_list args;
  449. int res;
  450. char buf[PREFIX_SIZE];
  451. BUG_ON(!descriptor);
  452. BUG_ON(!fmt);
  453. va_start(args, fmt);
  454. vaf.fmt = fmt;
  455. vaf.va = &args;
  456. res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
  457. va_end(args);
  458. return res;
  459. }
  460. EXPORT_SYMBOL(__dynamic_netdev_dbg);
  461. #endif
  462. static __initdata char ddebug_setup_string[1024];
  463. static __init int ddebug_setup_query(char *str)
  464. {
  465. if (strlen(str) >= 1024) {
  466. pr_warn("ddebug boot param string too large\n");
  467. return 0;
  468. }
  469. strcpy(ddebug_setup_string, str);
  470. return 1;
  471. }
  472. __setup("ddebug_query=", ddebug_setup_query);
  473. /*
  474. * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
  475. * command text from userspace, parses and executes it.
  476. */
  477. static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
  478. size_t len, loff_t *offp)
  479. {
  480. char tmpbuf[256];
  481. int ret;
  482. if (len == 0)
  483. return 0;
  484. /* we don't check *offp -- multiple writes() are allowed */
  485. if (len > sizeof(tmpbuf)-1)
  486. return -E2BIG;
  487. if (copy_from_user(tmpbuf, ubuf, len))
  488. return -EFAULT;
  489. tmpbuf[len] = '\0';
  490. if (verbose)
  491. pr_info("read %d bytes from userspace\n", (int)len);
  492. ret = ddebug_exec_query(tmpbuf);
  493. if (ret)
  494. return ret;
  495. *offp += len;
  496. return len;
  497. }
  498. /*
  499. * Set the iterator to point to the first _ddebug object
  500. * and return a pointer to that first object. Returns
  501. * NULL if there are no _ddebugs at all.
  502. */
  503. static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
  504. {
  505. if (list_empty(&ddebug_tables)) {
  506. iter->table = NULL;
  507. iter->idx = 0;
  508. return NULL;
  509. }
  510. iter->table = list_entry(ddebug_tables.next,
  511. struct ddebug_table, link);
  512. iter->idx = 0;
  513. return &iter->table->ddebugs[iter->idx];
  514. }
  515. /*
  516. * Advance the iterator to point to the next _ddebug
  517. * object from the one the iterator currently points at,
  518. * and returns a pointer to the new _ddebug. Returns
  519. * NULL if the iterator has seen all the _ddebugs.
  520. */
  521. static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
  522. {
  523. if (iter->table == NULL)
  524. return NULL;
  525. if (++iter->idx == iter->table->num_ddebugs) {
  526. /* iterate to next table */
  527. iter->idx = 0;
  528. if (list_is_last(&iter->table->link, &ddebug_tables)) {
  529. iter->table = NULL;
  530. return NULL;
  531. }
  532. iter->table = list_entry(iter->table->link.next,
  533. struct ddebug_table, link);
  534. }
  535. return &iter->table->ddebugs[iter->idx];
  536. }
  537. /*
  538. * Seq_ops start method. Called at the start of every
  539. * read() call from userspace. Takes the ddebug_lock and
  540. * seeks the seq_file's iterator to the given position.
  541. */
  542. static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
  543. {
  544. struct ddebug_iter *iter = m->private;
  545. struct _ddebug *dp;
  546. int n = *pos;
  547. if (verbose)
  548. pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
  549. mutex_lock(&ddebug_lock);
  550. if (!n)
  551. return SEQ_START_TOKEN;
  552. if (n < 0)
  553. return NULL;
  554. dp = ddebug_iter_first(iter);
  555. while (dp != NULL && --n > 0)
  556. dp = ddebug_iter_next(iter);
  557. return dp;
  558. }
  559. /*
  560. * Seq_ops next method. Called several times within a read()
  561. * call from userspace, with ddebug_lock held. Walks to the
  562. * next _ddebug object with a special case for the header line.
  563. */
  564. static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
  565. {
  566. struct ddebug_iter *iter = m->private;
  567. struct _ddebug *dp;
  568. if (verbose)
  569. pr_info("called m=%p p=%p *pos=%lld\n",
  570. m, p, (unsigned long long)*pos);
  571. if (p == SEQ_START_TOKEN)
  572. dp = ddebug_iter_first(iter);
  573. else
  574. dp = ddebug_iter_next(iter);
  575. ++*pos;
  576. return dp;
  577. }
  578. /*
  579. * Seq_ops show method. Called several times within a read()
  580. * call from userspace, with ddebug_lock held. Formats the
  581. * current _ddebug as a single human-readable line, with a
  582. * special case for the header line.
  583. */
  584. static int ddebug_proc_show(struct seq_file *m, void *p)
  585. {
  586. struct ddebug_iter *iter = m->private;
  587. struct _ddebug *dp = p;
  588. char flagsbuf[8];
  589. if (verbose)
  590. pr_info("called m=%p p=%p\n", m, p);
  591. if (p == SEQ_START_TOKEN) {
  592. seq_puts(m,
  593. "# filename:lineno [module]function flags format\n");
  594. return 0;
  595. }
  596. seq_printf(m, "%s:%u [%s]%s %s \"",
  597. dp->filename, dp->lineno,
  598. iter->table->mod_name, dp->function,
  599. ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
  600. seq_escape(m, dp->format, "\t\r\n\"");
  601. seq_puts(m, "\"\n");
  602. return 0;
  603. }
  604. /*
  605. * Seq_ops stop method. Called at the end of each read()
  606. * call from userspace. Drops ddebug_lock.
  607. */
  608. static void ddebug_proc_stop(struct seq_file *m, void *p)
  609. {
  610. if (verbose)
  611. pr_info("called m=%p p=%p\n", m, p);
  612. mutex_unlock(&ddebug_lock);
  613. }
  614. static const struct seq_operations ddebug_proc_seqops = {
  615. .start = ddebug_proc_start,
  616. .next = ddebug_proc_next,
  617. .show = ddebug_proc_show,
  618. .stop = ddebug_proc_stop
  619. };
  620. /*
  621. * File_ops->open method for <debugfs>/dynamic_debug/control. Does
  622. * the seq_file setup dance, and also creates an iterator to walk the
  623. * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
  624. * files where it's not needed, as doing so simplifies the ->release
  625. * method.
  626. */
  627. static int ddebug_proc_open(struct inode *inode, struct file *file)
  628. {
  629. struct ddebug_iter *iter;
  630. int err;
  631. if (verbose)
  632. pr_info("called\n");
  633. iter = kzalloc(sizeof(*iter), GFP_KERNEL);
  634. if (iter == NULL)
  635. return -ENOMEM;
  636. err = seq_open(file, &ddebug_proc_seqops);
  637. if (err) {
  638. kfree(iter);
  639. return err;
  640. }
  641. ((struct seq_file *) file->private_data)->private = iter;
  642. return 0;
  643. }
  644. static const struct file_operations ddebug_proc_fops = {
  645. .owner = THIS_MODULE,
  646. .open = ddebug_proc_open,
  647. .read = seq_read,
  648. .llseek = seq_lseek,
  649. .release = seq_release_private,
  650. .write = ddebug_proc_write
  651. };
  652. /*
  653. * Allocate a new ddebug_table for the given module
  654. * and add it to the global list.
  655. */
  656. int ddebug_add_module(struct _ddebug *tab, unsigned int n,
  657. const char *name)
  658. {
  659. struct ddebug_table *dt;
  660. char *new_name;
  661. dt = kzalloc(sizeof(*dt), GFP_KERNEL);
  662. if (dt == NULL)
  663. return -ENOMEM;
  664. new_name = kstrdup(name, GFP_KERNEL);
  665. if (new_name == NULL) {
  666. kfree(dt);
  667. return -ENOMEM;
  668. }
  669. dt->mod_name = new_name;
  670. dt->num_ddebugs = n;
  671. dt->ddebugs = tab;
  672. mutex_lock(&ddebug_lock);
  673. list_add_tail(&dt->link, &ddebug_tables);
  674. mutex_unlock(&ddebug_lock);
  675. if (verbose)
  676. pr_info("%u debug prints in module %s\n", n, dt->mod_name);
  677. return 0;
  678. }
  679. EXPORT_SYMBOL_GPL(ddebug_add_module);
  680. static void ddebug_table_free(struct ddebug_table *dt)
  681. {
  682. list_del_init(&dt->link);
  683. kfree(dt->mod_name);
  684. kfree(dt);
  685. }
  686. /*
  687. * Called in response to a module being unloaded. Removes
  688. * any ddebug_table's which point at the module.
  689. */
  690. int ddebug_remove_module(const char *mod_name)
  691. {
  692. struct ddebug_table *dt, *nextdt;
  693. int ret = -ENOENT;
  694. if (verbose)
  695. pr_info("removing module \"%s\"\n", mod_name);
  696. mutex_lock(&ddebug_lock);
  697. list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
  698. if (!strcmp(dt->mod_name, mod_name)) {
  699. ddebug_table_free(dt);
  700. ret = 0;
  701. }
  702. }
  703. mutex_unlock(&ddebug_lock);
  704. return ret;
  705. }
  706. EXPORT_SYMBOL_GPL(ddebug_remove_module);
  707. static void ddebug_remove_all_tables(void)
  708. {
  709. mutex_lock(&ddebug_lock);
  710. while (!list_empty(&ddebug_tables)) {
  711. struct ddebug_table *dt = list_entry(ddebug_tables.next,
  712. struct ddebug_table,
  713. link);
  714. ddebug_table_free(dt);
  715. }
  716. mutex_unlock(&ddebug_lock);
  717. }
  718. static __initdata int ddebug_init_success;
  719. static int __init dynamic_debug_init_debugfs(void)
  720. {
  721. struct dentry *dir, *file;
  722. if (!ddebug_init_success)
  723. return -ENODEV;
  724. dir = debugfs_create_dir("dynamic_debug", NULL);
  725. if (!dir)
  726. return -ENOMEM;
  727. file = debugfs_create_file("control", 0644, dir, NULL,
  728. &ddebug_proc_fops);
  729. if (!file) {
  730. debugfs_remove(dir);
  731. return -ENOMEM;
  732. }
  733. return 0;
  734. }
  735. static int __init dynamic_debug_init(void)
  736. {
  737. struct _ddebug *iter, *iter_start;
  738. const char *modname = NULL;
  739. int ret = 0;
  740. int n = 0;
  741. if (__start___verbose != __stop___verbose) {
  742. iter = __start___verbose;
  743. modname = iter->modname;
  744. iter_start = iter;
  745. for (; iter < __stop___verbose; iter++) {
  746. if (strcmp(modname, iter->modname)) {
  747. ret = ddebug_add_module(iter_start, n, modname);
  748. if (ret)
  749. goto out_free;
  750. n = 0;
  751. modname = iter->modname;
  752. iter_start = iter;
  753. }
  754. n++;
  755. }
  756. ret = ddebug_add_module(iter_start, n, modname);
  757. }
  758. /* ddebug_query boot param got passed -> set it up */
  759. if (ddebug_setup_string[0] != '\0') {
  760. ret = ddebug_exec_query(ddebug_setup_string);
  761. if (ret)
  762. pr_warn("Invalid ddebug boot param %s",
  763. ddebug_setup_string);
  764. else
  765. pr_info("ddebug initialized with string %s",
  766. ddebug_setup_string);
  767. }
  768. out_free:
  769. if (ret)
  770. ddebug_remove_all_tables();
  771. else
  772. ddebug_init_success = 1;
  773. return 0;
  774. }
  775. /* Allow early initialization for boot messages via boot param */
  776. arch_initcall(dynamic_debug_init);
  777. /* Debugfs setup must be done later */
  778. module_init(dynamic_debug_init_debugfs);