4 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
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.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/kallsyms.h>
16 #include <linux/version.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>
30 extern struct _ddebug __start___verbose[];
31 extern struct _ddebug __stop___verbose[];
33 /* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which
34 * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
35 * use independent hash functions, to reduce the chance of false positives.
37 long long dynamic_debug_enabled;
38 EXPORT_SYMBOL_GPL(dynamic_debug_enabled);
39 long long dynamic_debug_enabled2;
40 EXPORT_SYMBOL_GPL(dynamic_debug_enabled2);
43 struct list_head link;
45 unsigned int num_ddebugs;
46 unsigned int num_enabled;
47 struct _ddebug *ddebugs;
55 unsigned int first_lineno, last_lineno;
59 struct ddebug_table *table;
63 static DEFINE_MUTEX(ddebug_lock);
64 static LIST_HEAD(ddebug_tables);
65 static int verbose = 0;
67 /* Return the last part of a pathname */
68 static inline const char *basename(const char *path)
70 const char *tail = strrchr(path, '/');
71 return tail ? tail+1 : path;
74 /* format a string into buf[] which describes the _ddebug's flags */
75 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
81 if (dp->flags & _DPRINTK_FLAGS_PRINT)
91 * must be called with ddebug_lock held
94 static int disabled_hash(char hash, bool first_table)
96 struct ddebug_table *dt;
97 char table_hash_value;
99 list_for_each_entry(dt, &ddebug_tables, link) {
101 table_hash_value = dt->ddebugs->primary_hash;
103 table_hash_value = dt->ddebugs->secondary_hash;
104 if (dt->num_enabled && (hash == table_hash_value))
111 * Search the tables for _ddebug's which match the given
112 * `query' and apply the `flags' and `mask' to them. Tells
113 * the user which ddebug's were changed, or whether none
116 static void ddebug_change(const struct ddebug_query *query,
117 unsigned int flags, unsigned int mask)
120 struct ddebug_table *dt;
121 unsigned int newflags;
122 unsigned int nfound = 0;
125 /* search for matching ddebugs */
126 mutex_lock(&ddebug_lock);
127 list_for_each_entry(dt, &ddebug_tables, link) {
129 /* match against the module name */
130 if (query->module != NULL &&
131 strcmp(query->module, dt->mod_name))
134 for (i = 0 ; i < dt->num_ddebugs ; i++) {
135 struct _ddebug *dp = &dt->ddebugs[i];
137 /* match against the source filename */
138 if (query->filename != NULL &&
139 strcmp(query->filename, dp->filename) &&
140 strcmp(query->filename, basename(dp->filename)))
143 /* match against the function */
144 if (query->function != NULL &&
145 strcmp(query->function, dp->function))
148 /* match against the format */
149 if (query->format != NULL &&
150 strstr(dp->format, query->format) == NULL)
153 /* match against the line number range */
154 if (query->first_lineno &&
155 dp->lineno < query->first_lineno)
157 if (query->last_lineno &&
158 dp->lineno > query->last_lineno)
163 newflags = (dp->flags & mask) | flags;
164 if (newflags == dp->flags)
171 dp->flags = newflags;
173 dynamic_debug_enabled |=
174 (1LL << dp->primary_hash);
175 dynamic_debug_enabled2 |=
176 (1LL << dp->secondary_hash);
178 if (disabled_hash(dp->primary_hash, true))
179 dynamic_debug_enabled &=
180 ~(1LL << dp->primary_hash);
181 if (disabled_hash(dp->secondary_hash, false))
182 dynamic_debug_enabled2 &=
183 ~(1LL << dp->secondary_hash);
187 "ddebug: changed %s:%d [%s]%s %s\n",
188 dp->filename, dp->lineno,
189 dt->mod_name, dp->function,
190 ddebug_describe_flags(dp, flagbuf,
194 mutex_unlock(&ddebug_lock);
196 if (!nfound && verbose)
197 printk(KERN_INFO "ddebug: no matches for query\n");
201 * Split the buffer `buf' into space-separated words.
202 * Handles simple " and ' quoting, i.e. without nested,
203 * embedded or escaped \". Return the number of words
206 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
213 /* Skip leading whitespace */
214 buf = skip_spaces(buf);
216 break; /* oh, it was trailing whitespace */
218 /* Run `end' over a word, either whitespace separated or quoted */
219 if (*buf == '"' || *buf == '\'') {
221 for (end = buf ; *end && *end != quote ; end++)
224 return -EINVAL; /* unclosed quote */
226 for (end = buf ; *end && !isspace(*end) ; end++)
230 /* Here `buf' is the start of the word, `end' is one past the end */
232 if (nwords == maxwords)
233 return -EINVAL; /* ran out of words[] before bytes */
235 *end++ = '\0'; /* terminate the word */
236 words[nwords++] = buf;
242 printk(KERN_INFO "%s: split into words:", __func__);
243 for (i = 0 ; i < nwords ; i++)
244 printk(" \"%s\"", words[i]);
252 * Parse a single line number. Note that the empty string ""
253 * is treated as a special case and converted to zero, which
254 * is later treated as a "don't care" value.
256 static inline int parse_lineno(const char *str, unsigned int *val)
264 *val = simple_strtoul(str, &end, 10);
265 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
269 * Undo octal escaping in a string, inplace. This is useful to
270 * allow the user to express a query which matches a format
271 * containing embedded spaces.
273 #define isodigit(c) ((c) >= '0' && (c) <= '7')
274 static char *unescape(char *str)
285 } else if (in[1] == 't') {
289 } else if (in[1] == 'n') {
293 } else if (isodigit(in[1]) &&
296 *out++ = ((in[1] - '0')<<6) |
311 * Parse words[] as a ddebug query specification, which is a series
312 * of (keyword, value) pairs chosen from these possibilities:
314 * func <function-name>
315 * file <full-pathname>
316 * file <base-filename>
317 * module <module-name>
318 * format <escaped-string-to-find-in-format>
320 * line <first-lineno>-<last-lineno> // where either may be empty
322 static int ddebug_parse_query(char *words[], int nwords,
323 struct ddebug_query *query)
327 /* check we have an even number of words */
330 memset(query, 0, sizeof(*query));
332 for (i = 0 ; i < nwords ; i += 2) {
333 if (!strcmp(words[i], "func"))
334 query->function = words[i+1];
335 else if (!strcmp(words[i], "file"))
336 query->filename = words[i+1];
337 else if (!strcmp(words[i], "module"))
338 query->module = words[i+1];
339 else if (!strcmp(words[i], "format"))
340 query->format = unescape(words[i+1]);
341 else if (!strcmp(words[i], "line")) {
342 char *first = words[i+1];
343 char *last = strchr(first, '-');
346 if (parse_lineno(first, &query->first_lineno) < 0)
349 /* range <first>-<last> */
350 if (parse_lineno(last, &query->last_lineno) < 0)
353 query->last_lineno = query->first_lineno;
357 printk(KERN_ERR "%s: unknown keyword \"%s\"\n",
364 printk(KERN_INFO "%s: q->function=\"%s\" q->filename=\"%s\" "
365 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
366 __func__, query->function, query->filename,
367 query->module, query->format, query->first_lineno,
374 * Parse `str' as a flags specification, format [-+=][p]+.
375 * Sets up *maskp and *flagsp to be used when changing the
376 * flags fields of matched _ddebug's. Returns 0 on success
379 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
395 printk(KERN_INFO "%s: op='%c'\n", __func__, op);
397 for ( ; *str ; ++str) {
400 flags |= _DPRINTK_FLAGS_PRINT;
409 printk(KERN_INFO "%s: flags=0x%x\n", __func__, flags);
411 /* calculate final *flagsp, *maskp according to mask and op */
427 printk(KERN_INFO "%s: *flagsp=0x%x *maskp=0x%x\n",
428 __func__, *flagsp, *maskp);
432 static int ddebug_exec_query(char *query_string)
434 unsigned int flags = 0, mask = 0;
435 struct ddebug_query query;
438 char *words[MAXWORDS];
440 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
443 if (ddebug_parse_query(words, nwords-1, &query))
445 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
448 /* actually go and implement the change */
449 ddebug_change(&query, flags, mask);
453 static __initdata char ddebug_setup_string[1024];
454 static __init int ddebug_setup_query(char *str)
456 if (strlen(str) >= 1024) {
457 pr_warning("ddebug boot param string too large\n");
460 strcpy(ddebug_setup_string, str);
464 __setup("ddebug_query=", ddebug_setup_query);
467 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
468 * command text from userspace, parses and executes it.
470 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
471 size_t len, loff_t *offp)
478 /* we don't check *offp -- multiple writes() are allowed */
479 if (len > sizeof(tmpbuf)-1)
481 if (copy_from_user(tmpbuf, ubuf, len))
485 printk(KERN_INFO "%s: read %d bytes from userspace\n",
488 ret = ddebug_exec_query(tmpbuf);
497 * Set the iterator to point to the first _ddebug object
498 * and return a pointer to that first object. Returns
499 * NULL if there are no _ddebugs at all.
501 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
503 if (list_empty(&ddebug_tables)) {
508 iter->table = list_entry(ddebug_tables.next,
509 struct ddebug_table, link);
511 return &iter->table->ddebugs[iter->idx];
515 * Advance the iterator to point to the next _ddebug
516 * object from the one the iterator currently points at,
517 * and returns a pointer to the new _ddebug. Returns
518 * NULL if the iterator has seen all the _ddebugs.
520 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
522 if (iter->table == NULL)
524 if (++iter->idx == iter->table->num_ddebugs) {
525 /* iterate to next table */
527 if (list_is_last(&iter->table->link, &ddebug_tables)) {
531 iter->table = list_entry(iter->table->link.next,
532 struct ddebug_table, link);
534 return &iter->table->ddebugs[iter->idx];
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.
542 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
544 struct ddebug_iter *iter = m->private;
549 printk(KERN_INFO "%s: called m=%p *pos=%lld\n",
550 __func__, m, (unsigned long long)*pos);
552 mutex_lock(&ddebug_lock);
555 return SEQ_START_TOKEN;
558 dp = ddebug_iter_first(iter);
559 while (dp != NULL && --n > 0)
560 dp = ddebug_iter_next(iter);
565 * Seq_ops next method. Called several times within a read()
566 * call from userspace, with ddebug_lock held. Walks to the
567 * next _ddebug object with a special case for the header line.
569 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
571 struct ddebug_iter *iter = m->private;
575 printk(KERN_INFO "%s: called m=%p p=%p *pos=%lld\n",
576 __func__, m, p, (unsigned long long)*pos);
578 if (p == SEQ_START_TOKEN)
579 dp = ddebug_iter_first(iter);
581 dp = ddebug_iter_next(iter);
587 * Seq_ops show method. Called several times within a read()
588 * call from userspace, with ddebug_lock held. Formats the
589 * current _ddebug as a single human-readable line, with a
590 * special case for the header line.
592 static int ddebug_proc_show(struct seq_file *m, void *p)
594 struct ddebug_iter *iter = m->private;
595 struct _ddebug *dp = p;
599 printk(KERN_INFO "%s: called m=%p p=%p\n",
602 if (p == SEQ_START_TOKEN) {
604 "# filename:lineno [module]function flags format\n");
608 seq_printf(m, "%s:%u [%s]%s %s \"",
609 dp->filename, dp->lineno,
610 iter->table->mod_name, dp->function,
611 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
612 seq_escape(m, dp->format, "\t\r\n\"");
619 * Seq_ops stop method. Called at the end of each read()
620 * call from userspace. Drops ddebug_lock.
622 static void ddebug_proc_stop(struct seq_file *m, void *p)
625 printk(KERN_INFO "%s: called m=%p p=%p\n",
627 mutex_unlock(&ddebug_lock);
630 static const struct seq_operations ddebug_proc_seqops = {
631 .start = ddebug_proc_start,
632 .next = ddebug_proc_next,
633 .show = ddebug_proc_show,
634 .stop = ddebug_proc_stop
638 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
639 * setup dance, and also creates an iterator to walk the _ddebugs.
640 * Note that we create a seq_file always, even for O_WRONLY files
641 * where it's not needed, as doing so simplifies the ->release method.
643 static int ddebug_proc_open(struct inode *inode, struct file *file)
645 struct ddebug_iter *iter;
649 printk(KERN_INFO "%s: called\n", __func__);
651 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
655 err = seq_open(file, &ddebug_proc_seqops);
660 ((struct seq_file *) file->private_data)->private = iter;
664 static const struct file_operations ddebug_proc_fops = {
665 .owner = THIS_MODULE,
666 .open = ddebug_proc_open,
669 .release = seq_release_private,
670 .write = ddebug_proc_write
674 * Allocate a new ddebug_table for the given module
675 * and add it to the global list.
677 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
680 struct ddebug_table *dt;
683 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
686 new_name = kstrdup(name, GFP_KERNEL);
687 if (new_name == NULL) {
691 dt->mod_name = new_name;
696 mutex_lock(&ddebug_lock);
697 list_add_tail(&dt->link, &ddebug_tables);
698 mutex_unlock(&ddebug_lock);
701 printk(KERN_INFO "%u debug prints in module %s\n",
705 EXPORT_SYMBOL_GPL(ddebug_add_module);
707 static void ddebug_table_free(struct ddebug_table *dt)
709 list_del_init(&dt->link);
715 * Called in response to a module being unloaded. Removes
716 * any ddebug_table's which point at the module.
718 int ddebug_remove_module(const char *mod_name)
720 struct ddebug_table *dt, *nextdt;
724 printk(KERN_INFO "%s: removing module \"%s\"\n",
727 mutex_lock(&ddebug_lock);
728 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
729 if (!strcmp(dt->mod_name, mod_name)) {
730 ddebug_table_free(dt);
734 mutex_unlock(&ddebug_lock);
737 EXPORT_SYMBOL_GPL(ddebug_remove_module);
739 static void ddebug_remove_all_tables(void)
741 mutex_lock(&ddebug_lock);
742 while (!list_empty(&ddebug_tables)) {
743 struct ddebug_table *dt = list_entry(ddebug_tables.next,
746 ddebug_table_free(dt);
748 mutex_unlock(&ddebug_lock);
751 static __initdata int ddebug_init_success;
753 static int __init dynamic_debug_init_debugfs(void)
755 struct dentry *dir, *file;
757 if (!ddebug_init_success)
760 dir = debugfs_create_dir("dynamic_debug", NULL);
763 file = debugfs_create_file("control", 0644, dir, NULL,
772 static int __init dynamic_debug_init(void)
774 struct _ddebug *iter, *iter_start;
775 const char *modname = NULL;
779 if (__start___verbose != __stop___verbose) {
780 iter = __start___verbose;
781 modname = iter->modname;
783 for (; iter < __stop___verbose; iter++) {
784 if (strcmp(modname, iter->modname)) {
785 ret = ddebug_add_module(iter_start, n, modname);
789 modname = iter->modname;
794 ret = ddebug_add_module(iter_start, n, modname);
797 /* ddebug_query boot param got passed -> set it up */
798 if (ddebug_setup_string[0] != '\0') {
799 ret = ddebug_exec_query(ddebug_setup_string);
801 pr_warning("Invalid ddebug boot param %s",
802 ddebug_setup_string);
804 pr_info("ddebug initialized with string %s",
805 ddebug_setup_string);
810 ddebug_remove_all_tables();
812 ddebug_init_success = 1;
815 /* Allow early initialization for boot messages via boot param */
816 arch_initcall(dynamic_debug_init);
817 /* Debugfs setup must be done later */
818 module_init(dynamic_debug_init_debugfs);