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.
10 * Copyright (C) 2011 Bart Van Assche. All Rights Reserved.
13 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/kallsyms.h>
19 #include <linux/version.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/uaccess.h>
29 #include <linux/dynamic_debug.h>
30 #include <linux/debugfs.h>
31 #include <linux/slab.h>
32 #include <linux/jump_label.h>
33 #include <linux/hardirq.h>
34 #include <linux/sched.h>
35 #include <linux/device.h>
36 #include <linux/netdevice.h>
38 extern struct _ddebug __start___verbose[];
39 extern struct _ddebug __stop___verbose[];
42 struct list_head link;
44 unsigned int num_ddebugs;
45 unsigned int num_enabled;
46 struct _ddebug *ddebugs;
54 unsigned int first_lineno, last_lineno;
58 struct ddebug_table *table;
62 static DEFINE_MUTEX(ddebug_lock);
63 static LIST_HEAD(ddebug_tables);
64 static int verbose = 0;
66 /* Return the last part of a pathname */
67 static inline const char *basename(const char *path)
69 const char *tail = strrchr(path, '/');
70 return tail ? tail+1 : path;
73 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
74 { _DPRINTK_FLAGS_PRINT, 'p' },
75 { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
76 { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
77 { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
78 { _DPRINTK_FLAGS_INCL_TID, 't' },
81 /* format a string into buf[] which describes the _ddebug's flags */
82 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
89 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
90 if (dp->flags & opt_array[i].flag)
91 *p++ = opt_array[i].opt_char;
100 * Search the tables for _ddebug's which match the given
101 * `query' and apply the `flags' and `mask' to them. Tells
102 * the user which ddebug's were changed, or whether none
105 static void ddebug_change(const struct ddebug_query *query,
106 unsigned int flags, unsigned int mask)
109 struct ddebug_table *dt;
110 unsigned int newflags;
111 unsigned int nfound = 0;
114 /* search for matching ddebugs */
115 mutex_lock(&ddebug_lock);
116 list_for_each_entry(dt, &ddebug_tables, link) {
118 /* match against the module name */
119 if (query->module != NULL &&
120 strcmp(query->module, dt->mod_name))
123 for (i = 0 ; i < dt->num_ddebugs ; i++) {
124 struct _ddebug *dp = &dt->ddebugs[i];
126 /* match against the source filename */
127 if (query->filename != NULL &&
128 strcmp(query->filename, dp->filename) &&
129 strcmp(query->filename, basename(dp->filename)))
132 /* match against the function */
133 if (query->function != NULL &&
134 strcmp(query->function, dp->function))
137 /* match against the format */
138 if (query->format != NULL &&
139 strstr(dp->format, query->format) == NULL)
142 /* match against the line number range */
143 if (query->first_lineno &&
144 dp->lineno < query->first_lineno)
146 if (query->last_lineno &&
147 dp->lineno > query->last_lineno)
152 newflags = (dp->flags & mask) | flags;
153 if (newflags == dp->flags)
160 dp->flags = newflags;
166 pr_info("changed %s:%d [%s]%s %s\n",
167 dp->filename, dp->lineno,
168 dt->mod_name, dp->function,
169 ddebug_describe_flags(dp, flagbuf,
173 mutex_unlock(&ddebug_lock);
175 if (!nfound && verbose)
176 pr_info("no matches for query\n");
180 * Split the buffer `buf' into space-separated words.
181 * Handles simple " and ' quoting, i.e. without nested,
182 * embedded or escaped \". Return the number of words
185 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
192 /* Skip leading whitespace */
193 buf = skip_spaces(buf);
195 break; /* oh, it was trailing whitespace */
197 /* Run `end' over a word, either whitespace separated or quoted */
198 if (*buf == '"' || *buf == '\'') {
200 for (end = buf ; *end && *end != quote ; end++)
203 return -EINVAL; /* unclosed quote */
205 for (end = buf ; *end && !isspace(*end) ; end++)
209 /* Here `buf' is the start of the word, `end' is one past the end */
211 if (nwords == maxwords)
212 return -EINVAL; /* ran out of words[] before bytes */
214 *end++ = '\0'; /* terminate the word */
215 words[nwords++] = buf;
221 pr_info("split into words:");
222 for (i = 0 ; i < nwords ; i++)
223 pr_cont(" \"%s\"", words[i]);
231 * Parse a single line number. Note that the empty string ""
232 * is treated as a special case and converted to zero, which
233 * is later treated as a "don't care" value.
235 static inline int parse_lineno(const char *str, unsigned int *val)
243 *val = simple_strtoul(str, &end, 10);
244 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
248 * Undo octal escaping in a string, inplace. This is useful to
249 * allow the user to express a query which matches a format
250 * containing embedded spaces.
252 #define isodigit(c) ((c) >= '0' && (c) <= '7')
253 static char *unescape(char *str)
264 } else if (in[1] == 't') {
268 } else if (in[1] == 'n') {
272 } else if (isodigit(in[1]) &&
275 *out++ = ((in[1] - '0')<<6) |
290 * Parse words[] as a ddebug query specification, which is a series
291 * of (keyword, value) pairs chosen from these possibilities:
293 * func <function-name>
294 * file <full-pathname>
295 * file <base-filename>
296 * module <module-name>
297 * format <escaped-string-to-find-in-format>
299 * line <first-lineno>-<last-lineno> // where either may be empty
301 static int ddebug_parse_query(char *words[], int nwords,
302 struct ddebug_query *query)
306 /* check we have an even number of words */
309 memset(query, 0, sizeof(*query));
311 for (i = 0 ; i < nwords ; i += 2) {
312 if (!strcmp(words[i], "func"))
313 query->function = words[i+1];
314 else if (!strcmp(words[i], "file"))
315 query->filename = words[i+1];
316 else if (!strcmp(words[i], "module"))
317 query->module = words[i+1];
318 else if (!strcmp(words[i], "format"))
319 query->format = unescape(words[i+1]);
320 else if (!strcmp(words[i], "line")) {
321 char *first = words[i+1];
322 char *last = strchr(first, '-');
325 if (parse_lineno(first, &query->first_lineno) < 0)
328 /* range <first>-<last> */
329 if (parse_lineno(last, &query->last_lineno) < 0)
332 query->last_lineno = query->first_lineno;
336 pr_err("unknown keyword \"%s\"\n", words[i]);
342 pr_info("q->function=\"%s\" q->filename=\"%s\" "
343 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
344 query->function, query->filename,
345 query->module, query->format, query->first_lineno,
352 * Parse `str' as a flags specification, format [-+=][p]+.
353 * Sets up *maskp and *flagsp to be used when changing the
354 * flags fields of matched _ddebug's. Returns 0 on success
357 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
373 pr_info("op='%c'\n", op);
375 for ( ; *str ; ++str) {
376 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
377 if (*str == opt_array[i].opt_char) {
378 flags |= opt_array[i].flag;
388 pr_info("flags=0x%x\n", flags);
390 /* calculate final *flagsp, *maskp according to mask and op */
406 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
410 static int ddebug_exec_query(char *query_string)
412 unsigned int flags = 0, mask = 0;
413 struct ddebug_query query;
416 char *words[MAXWORDS];
418 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
421 if (ddebug_parse_query(words, nwords-1, &query))
423 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
426 /* actually go and implement the change */
427 ddebug_change(&query, flags, mask);
431 static int dynamic_emit_prefix(const struct _ddebug *descriptor)
433 char tid[sizeof(int) + sizeof(int)/2 + 4];
434 char lineno[sizeof(int) + sizeof(int)/2];
436 if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {
438 snprintf(tid, sizeof(tid), "%s", "<intr> ");
440 snprintf(tid, sizeof(tid), "[%d] ",
441 task_pid_vnr(current));
446 if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
447 snprintf(lineno, sizeof(lineno), "%d", descriptor->lineno);
451 return printk(KERN_DEBUG "%s%s%s%s%s%s",
453 (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
454 descriptor->modname : "",
455 (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
457 (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
458 descriptor->function : "",
459 (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
464 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
474 res = dynamic_emit_prefix(descriptor);
475 res += vprintk(fmt, args);
481 EXPORT_SYMBOL(__dynamic_pr_debug);
483 int __dynamic_dev_dbg(struct _ddebug *descriptor,
484 const struct device *dev, const char *fmt, ...)
486 struct va_format vaf;
498 res = dynamic_emit_prefix(descriptor);
499 res += __dev_printk(KERN_CONT, dev, &vaf);
505 EXPORT_SYMBOL(__dynamic_dev_dbg);
507 int __dynamic_netdev_dbg(struct _ddebug *descriptor,
508 const struct net_device *dev, const char *fmt, ...)
510 struct va_format vaf;
522 res = dynamic_emit_prefix(descriptor);
523 res += __netdev_printk(KERN_CONT, dev, &vaf);
529 EXPORT_SYMBOL(__dynamic_netdev_dbg);
531 static __initdata char ddebug_setup_string[1024];
532 static __init int ddebug_setup_query(char *str)
534 if (strlen(str) >= 1024) {
535 pr_warn("ddebug boot param string too large\n");
538 strcpy(ddebug_setup_string, str);
542 __setup("ddebug_query=", ddebug_setup_query);
545 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
546 * command text from userspace, parses and executes it.
548 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
549 size_t len, loff_t *offp)
556 /* we don't check *offp -- multiple writes() are allowed */
557 if (len > sizeof(tmpbuf)-1)
559 if (copy_from_user(tmpbuf, ubuf, len))
563 pr_info("read %d bytes from userspace\n", (int)len);
565 ret = ddebug_exec_query(tmpbuf);
574 * Set the iterator to point to the first _ddebug object
575 * and return a pointer to that first object. Returns
576 * NULL if there are no _ddebugs at all.
578 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
580 if (list_empty(&ddebug_tables)) {
585 iter->table = list_entry(ddebug_tables.next,
586 struct ddebug_table, link);
588 return &iter->table->ddebugs[iter->idx];
592 * Advance the iterator to point to the next _ddebug
593 * object from the one the iterator currently points at,
594 * and returns a pointer to the new _ddebug. Returns
595 * NULL if the iterator has seen all the _ddebugs.
597 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
599 if (iter->table == NULL)
601 if (++iter->idx == iter->table->num_ddebugs) {
602 /* iterate to next table */
604 if (list_is_last(&iter->table->link, &ddebug_tables)) {
608 iter->table = list_entry(iter->table->link.next,
609 struct ddebug_table, link);
611 return &iter->table->ddebugs[iter->idx];
615 * Seq_ops start method. Called at the start of every
616 * read() call from userspace. Takes the ddebug_lock and
617 * seeks the seq_file's iterator to the given position.
619 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
621 struct ddebug_iter *iter = m->private;
626 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
628 mutex_lock(&ddebug_lock);
631 return SEQ_START_TOKEN;
634 dp = ddebug_iter_first(iter);
635 while (dp != NULL && --n > 0)
636 dp = ddebug_iter_next(iter);
641 * Seq_ops next method. Called several times within a read()
642 * call from userspace, with ddebug_lock held. Walks to the
643 * next _ddebug object with a special case for the header line.
645 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
647 struct ddebug_iter *iter = m->private;
651 pr_info("called m=%p p=%p *pos=%lld\n",
652 m, p, (unsigned long long)*pos);
654 if (p == SEQ_START_TOKEN)
655 dp = ddebug_iter_first(iter);
657 dp = ddebug_iter_next(iter);
663 * Seq_ops show method. Called several times within a read()
664 * call from userspace, with ddebug_lock held. Formats the
665 * current _ddebug as a single human-readable line, with a
666 * special case for the header line.
668 static int ddebug_proc_show(struct seq_file *m, void *p)
670 struct ddebug_iter *iter = m->private;
671 struct _ddebug *dp = p;
675 pr_info("called m=%p p=%p\n", m, p);
677 if (p == SEQ_START_TOKEN) {
679 "# filename:lineno [module]function flags format\n");
683 seq_printf(m, "%s:%u [%s]%s %s \"",
684 dp->filename, dp->lineno,
685 iter->table->mod_name, dp->function,
686 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
687 seq_escape(m, dp->format, "\t\r\n\"");
694 * Seq_ops stop method. Called at the end of each read()
695 * call from userspace. Drops ddebug_lock.
697 static void ddebug_proc_stop(struct seq_file *m, void *p)
700 pr_info("called m=%p p=%p\n", m, p);
701 mutex_unlock(&ddebug_lock);
704 static const struct seq_operations ddebug_proc_seqops = {
705 .start = ddebug_proc_start,
706 .next = ddebug_proc_next,
707 .show = ddebug_proc_show,
708 .stop = ddebug_proc_stop
712 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
713 * setup dance, and also creates an iterator to walk the _ddebugs.
714 * Note that we create a seq_file always, even for O_WRONLY files
715 * where it's not needed, as doing so simplifies the ->release method.
717 static int ddebug_proc_open(struct inode *inode, struct file *file)
719 struct ddebug_iter *iter;
725 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
729 err = seq_open(file, &ddebug_proc_seqops);
734 ((struct seq_file *) file->private_data)->private = iter;
738 static const struct file_operations ddebug_proc_fops = {
739 .owner = THIS_MODULE,
740 .open = ddebug_proc_open,
743 .release = seq_release_private,
744 .write = ddebug_proc_write
748 * Allocate a new ddebug_table for the given module
749 * and add it to the global list.
751 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
754 struct ddebug_table *dt;
757 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
760 new_name = kstrdup(name, GFP_KERNEL);
761 if (new_name == NULL) {
765 dt->mod_name = new_name;
770 mutex_lock(&ddebug_lock);
771 list_add_tail(&dt->link, &ddebug_tables);
772 mutex_unlock(&ddebug_lock);
775 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
778 EXPORT_SYMBOL_GPL(ddebug_add_module);
780 static void ddebug_table_free(struct ddebug_table *dt)
782 list_del_init(&dt->link);
788 * Called in response to a module being unloaded. Removes
789 * any ddebug_table's which point at the module.
791 int ddebug_remove_module(const char *mod_name)
793 struct ddebug_table *dt, *nextdt;
797 pr_info("removing module \"%s\"\n", mod_name);
799 mutex_lock(&ddebug_lock);
800 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
801 if (!strcmp(dt->mod_name, mod_name)) {
802 ddebug_table_free(dt);
806 mutex_unlock(&ddebug_lock);
809 EXPORT_SYMBOL_GPL(ddebug_remove_module);
811 static void ddebug_remove_all_tables(void)
813 mutex_lock(&ddebug_lock);
814 while (!list_empty(&ddebug_tables)) {
815 struct ddebug_table *dt = list_entry(ddebug_tables.next,
818 ddebug_table_free(dt);
820 mutex_unlock(&ddebug_lock);
823 static __initdata int ddebug_init_success;
825 static int __init dynamic_debug_init_debugfs(void)
827 struct dentry *dir, *file;
829 if (!ddebug_init_success)
832 dir = debugfs_create_dir("dynamic_debug", NULL);
835 file = debugfs_create_file("control", 0644, dir, NULL,
844 static int __init dynamic_debug_init(void)
846 struct _ddebug *iter, *iter_start;
847 const char *modname = NULL;
851 if (__start___verbose != __stop___verbose) {
852 iter = __start___verbose;
853 modname = iter->modname;
855 for (; iter < __stop___verbose; iter++) {
856 if (strcmp(modname, iter->modname)) {
857 ret = ddebug_add_module(iter_start, n, modname);
861 modname = iter->modname;
866 ret = ddebug_add_module(iter_start, n, modname);
869 /* ddebug_query boot param got passed -> set it up */
870 if (ddebug_setup_string[0] != '\0') {
871 ret = ddebug_exec_query(ddebug_setup_string);
873 pr_warn("Invalid ddebug boot param %s",
874 ddebug_setup_string);
876 pr_info("ddebug initialized with string %s",
877 ddebug_setup_string);
882 ddebug_remove_all_tables();
884 ddebug_init_success = 1;
887 /* Allow early initialization for boot messages via boot param */
888 arch_initcall(dynamic_debug_init);
889 /* Debugfs setup must be done later */
890 module_init(dynamic_debug_init_debugfs);