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