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