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/types.h>
20 #include <linux/mutex.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/list.h>
24 #include <linux/sysctl.h>
25 #include <linux/ctype.h>
26 #include <linux/string.h>
27 #include <linux/uaccess.h>
28 #include <linux/dynamic_debug.h>
29 #include <linux/debugfs.h>
30 #include <linux/slab.h>
31 #include <linux/jump_label.h>
32 #include <linux/hardirq.h>
33 #include <linux/sched.h>
34 #include <linux/device.h>
35 #include <linux/netdevice.h>
37 extern struct _ddebug __start___verbose[];
38 extern struct _ddebug __stop___verbose[];
41 struct list_head link;
43 unsigned int num_ddebugs;
44 unsigned int num_enabled;
45 struct _ddebug *ddebugs;
53 unsigned int first_lineno, last_lineno;
57 struct ddebug_table *table;
61 static DEFINE_MUTEX(ddebug_lock);
62 static LIST_HEAD(ddebug_tables);
63 static int verbose = 0;
65 /* Return the last part of a pathname */
66 static inline const char *basename(const char *path)
68 const char *tail = strrchr(path, '/');
69 return tail ? tail+1 : path;
72 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
73 { _DPRINTK_FLAGS_PRINT, 'p' },
74 { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
75 { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
76 { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
77 { _DPRINTK_FLAGS_INCL_TID, 't' },
80 /* format a string into buf[] which describes the _ddebug's flags */
81 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
88 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
89 if (dp->flags & opt_array[i].flag)
90 *p++ = opt_array[i].opt_char;
99 * Search the tables for _ddebug's which match the given
100 * `query' and apply the `flags' and `mask' to them. Tells
101 * the user which ddebug's were changed, or whether none
104 static void ddebug_change(const struct ddebug_query *query,
105 unsigned int flags, unsigned int mask)
108 struct ddebug_table *dt;
109 unsigned int newflags;
110 unsigned int nfound = 0;
113 /* search for matching ddebugs */
114 mutex_lock(&ddebug_lock);
115 list_for_each_entry(dt, &ddebug_tables, link) {
117 /* match against the module name */
118 if (query->module != NULL &&
119 strcmp(query->module, dt->mod_name))
122 for (i = 0 ; i < dt->num_ddebugs ; i++) {
123 struct _ddebug *dp = &dt->ddebugs[i];
125 /* match against the source filename */
126 if (query->filename != NULL &&
127 strcmp(query->filename, dp->filename) &&
128 strcmp(query->filename, basename(dp->filename)))
131 /* match against the function */
132 if (query->function != NULL &&
133 strcmp(query->function, dp->function))
136 /* match against the format */
137 if (query->format != NULL &&
138 strstr(dp->format, query->format) == NULL)
141 /* match against the line number range */
142 if (query->first_lineno &&
143 dp->lineno < query->first_lineno)
145 if (query->last_lineno &&
146 dp->lineno > query->last_lineno)
151 newflags = (dp->flags & mask) | flags;
152 if (newflags == dp->flags)
159 dp->flags = newflags;
165 pr_info("changed %s:%d [%s]%s %s\n",
166 dp->filename, dp->lineno,
167 dt->mod_name, dp->function,
168 ddebug_describe_flags(dp, flagbuf,
172 mutex_unlock(&ddebug_lock);
174 if (!nfound && verbose)
175 pr_info("no matches for query\n");
179 * Split the buffer `buf' into space-separated words.
180 * Handles simple " and ' quoting, i.e. without nested,
181 * embedded or escaped \". Return the number of words
184 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
191 /* Skip leading whitespace */
192 buf = skip_spaces(buf);
194 break; /* oh, it was trailing whitespace */
196 /* Run `end' over a word, either whitespace separated or quoted */
197 if (*buf == '"' || *buf == '\'') {
199 for (end = buf ; *end && *end != quote ; end++)
202 return -EINVAL; /* unclosed quote */
204 for (end = buf ; *end && !isspace(*end) ; end++)
208 /* Here `buf' is the start of the word, `end' is one past the end */
210 if (nwords == maxwords)
211 return -EINVAL; /* ran out of words[] before bytes */
213 *end++ = '\0'; /* terminate the word */
214 words[nwords++] = buf;
220 pr_info("split into words:");
221 for (i = 0 ; i < nwords ; i++)
222 pr_cont(" \"%s\"", words[i]);
230 * Parse a single line number. Note that the empty string ""
231 * is treated as a special case and converted to zero, which
232 * is later treated as a "don't care" value.
234 static inline int parse_lineno(const char *str, unsigned int *val)
242 *val = simple_strtoul(str, &end, 10);
243 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
247 * Undo octal escaping in a string, inplace. This is useful to
248 * allow the user to express a query which matches a format
249 * containing embedded spaces.
251 #define isodigit(c) ((c) >= '0' && (c) <= '7')
252 static char *unescape(char *str)
263 } else if (in[1] == 't') {
267 } else if (in[1] == 'n') {
271 } else if (isodigit(in[1]) &&
274 *out++ = ((in[1] - '0')<<6) |
289 * Parse words[] as a ddebug query specification, which is a series
290 * of (keyword, value) pairs chosen from these possibilities:
292 * func <function-name>
293 * file <full-pathname>
294 * file <base-filename>
295 * module <module-name>
296 * format <escaped-string-to-find-in-format>
298 * line <first-lineno>-<last-lineno> // where either may be empty
300 static int ddebug_parse_query(char *words[], int nwords,
301 struct ddebug_query *query)
305 /* check we have an even number of words */
308 memset(query, 0, sizeof(*query));
310 for (i = 0 ; i < nwords ; i += 2) {
311 if (!strcmp(words[i], "func"))
312 query->function = words[i+1];
313 else if (!strcmp(words[i], "file"))
314 query->filename = words[i+1];
315 else if (!strcmp(words[i], "module"))
316 query->module = words[i+1];
317 else if (!strcmp(words[i], "format"))
318 query->format = unescape(words[i+1]);
319 else if (!strcmp(words[i], "line")) {
320 char *first = words[i+1];
321 char *last = strchr(first, '-');
324 if (parse_lineno(first, &query->first_lineno) < 0)
327 /* range <first>-<last> */
328 if (parse_lineno(last, &query->last_lineno) < 0)
331 query->last_lineno = query->first_lineno;
335 pr_err("unknown keyword \"%s\"\n", words[i]);
341 pr_info("q->function=\"%s\" q->filename=\"%s\" "
342 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
343 query->function, query->filename,
344 query->module, query->format, query->first_lineno,
351 * Parse `str' as a flags specification, format [-+=][p]+.
352 * Sets up *maskp and *flagsp to be used when changing the
353 * flags fields of matched _ddebug's. Returns 0 on success
356 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
372 pr_info("op='%c'\n", op);
374 for ( ; *str ; ++str) {
375 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
376 if (*str == opt_array[i].opt_char) {
377 flags |= opt_array[i].flag;
387 pr_info("flags=0x%x\n", flags);
389 /* calculate final *flagsp, *maskp according to mask and op */
405 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
409 static int ddebug_exec_query(char *query_string)
411 unsigned int flags = 0, mask = 0;
412 struct ddebug_query query;
415 char *words[MAXWORDS];
417 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
420 if (ddebug_parse_query(words, nwords-1, &query))
422 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
425 /* actually go and implement the change */
426 ddebug_change(&query, flags, mask);
430 static int dynamic_emit_prefix(const struct _ddebug *descriptor)
432 char tid[sizeof(int) + sizeof(int)/2 + 4];
433 char lineno[sizeof(int) + sizeof(int)/2];
435 if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {
437 snprintf(tid, sizeof(tid), "%s", "<intr> ");
439 snprintf(tid, sizeof(tid), "[%d] ",
440 task_pid_vnr(current));
445 if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
446 snprintf(lineno, sizeof(lineno), "%d", descriptor->lineno);
450 return printk(KERN_DEBUG "%s%s%s%s%s%s",
452 (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
453 descriptor->modname : "",
454 (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
456 (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
457 descriptor->function : "",
458 (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
463 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
473 res = dynamic_emit_prefix(descriptor);
474 res += vprintk(fmt, args);
480 EXPORT_SYMBOL(__dynamic_pr_debug);
482 int __dynamic_dev_dbg(struct _ddebug *descriptor,
483 const struct device *dev, const char *fmt, ...)
485 struct va_format vaf;
497 res = dynamic_emit_prefix(descriptor);
498 res += __dev_printk(KERN_CONT, dev, &vaf);
504 EXPORT_SYMBOL(__dynamic_dev_dbg);
506 int __dynamic_netdev_dbg(struct _ddebug *descriptor,
507 const struct net_device *dev, const char *fmt, ...)
509 struct va_format vaf;
521 res = dynamic_emit_prefix(descriptor);
522 res += __netdev_printk(KERN_CONT, dev, &vaf);
528 EXPORT_SYMBOL(__dynamic_netdev_dbg);
530 static __initdata char ddebug_setup_string[1024];
531 static __init int ddebug_setup_query(char *str)
533 if (strlen(str) >= 1024) {
534 pr_warn("ddebug boot param string too large\n");
537 strcpy(ddebug_setup_string, str);
541 __setup("ddebug_query=", ddebug_setup_query);
544 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
545 * command text from userspace, parses and executes it.
547 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
548 size_t len, loff_t *offp)
555 /* we don't check *offp -- multiple writes() are allowed */
556 if (len > sizeof(tmpbuf)-1)
558 if (copy_from_user(tmpbuf, ubuf, len))
562 pr_info("read %d bytes from userspace\n", (int)len);
564 ret = ddebug_exec_query(tmpbuf);
573 * Set the iterator to point to the first _ddebug object
574 * and return a pointer to that first object. Returns
575 * NULL if there are no _ddebugs at all.
577 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
579 if (list_empty(&ddebug_tables)) {
584 iter->table = list_entry(ddebug_tables.next,
585 struct ddebug_table, link);
587 return &iter->table->ddebugs[iter->idx];
591 * Advance the iterator to point to the next _ddebug
592 * object from the one the iterator currently points at,
593 * and returns a pointer to the new _ddebug. Returns
594 * NULL if the iterator has seen all the _ddebugs.
596 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
598 if (iter->table == NULL)
600 if (++iter->idx == iter->table->num_ddebugs) {
601 /* iterate to next table */
603 if (list_is_last(&iter->table->link, &ddebug_tables)) {
607 iter->table = list_entry(iter->table->link.next,
608 struct ddebug_table, link);
610 return &iter->table->ddebugs[iter->idx];
614 * Seq_ops start method. Called at the start of every
615 * read() call from userspace. Takes the ddebug_lock and
616 * seeks the seq_file's iterator to the given position.
618 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
620 struct ddebug_iter *iter = m->private;
625 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
627 mutex_lock(&ddebug_lock);
630 return SEQ_START_TOKEN;
633 dp = ddebug_iter_first(iter);
634 while (dp != NULL && --n > 0)
635 dp = ddebug_iter_next(iter);
640 * Seq_ops next method. Called several times within a read()
641 * call from userspace, with ddebug_lock held. Walks to the
642 * next _ddebug object with a special case for the header line.
644 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
646 struct ddebug_iter *iter = m->private;
650 pr_info("called m=%p p=%p *pos=%lld\n",
651 m, p, (unsigned long long)*pos);
653 if (p == SEQ_START_TOKEN)
654 dp = ddebug_iter_first(iter);
656 dp = ddebug_iter_next(iter);
662 * Seq_ops show method. Called several times within a read()
663 * call from userspace, with ddebug_lock held. Formats the
664 * current _ddebug as a single human-readable line, with a
665 * special case for the header line.
667 static int ddebug_proc_show(struct seq_file *m, void *p)
669 struct ddebug_iter *iter = m->private;
670 struct _ddebug *dp = p;
674 pr_info("called m=%p p=%p\n", m, p);
676 if (p == SEQ_START_TOKEN) {
678 "# filename:lineno [module]function flags format\n");
682 seq_printf(m, "%s:%u [%s]%s %s \"",
683 dp->filename, dp->lineno,
684 iter->table->mod_name, dp->function,
685 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
686 seq_escape(m, dp->format, "\t\r\n\"");
693 * Seq_ops stop method. Called at the end of each read()
694 * call from userspace. Drops ddebug_lock.
696 static void ddebug_proc_stop(struct seq_file *m, void *p)
699 pr_info("called m=%p p=%p\n", m, p);
700 mutex_unlock(&ddebug_lock);
703 static const struct seq_operations ddebug_proc_seqops = {
704 .start = ddebug_proc_start,
705 .next = ddebug_proc_next,
706 .show = ddebug_proc_show,
707 .stop = ddebug_proc_stop
711 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
712 * setup dance, and also creates an iterator to walk the _ddebugs.
713 * Note that we create a seq_file always, even for O_WRONLY files
714 * where it's not needed, as doing so simplifies the ->release method.
716 static int ddebug_proc_open(struct inode *inode, struct file *file)
718 struct ddebug_iter *iter;
724 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
728 err = seq_open(file, &ddebug_proc_seqops);
733 ((struct seq_file *) file->private_data)->private = iter;
737 static const struct file_operations ddebug_proc_fops = {
738 .owner = THIS_MODULE,
739 .open = ddebug_proc_open,
742 .release = seq_release_private,
743 .write = ddebug_proc_write
747 * Allocate a new ddebug_table for the given module
748 * and add it to the global list.
750 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
753 struct ddebug_table *dt;
756 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
759 new_name = kstrdup(name, GFP_KERNEL);
760 if (new_name == NULL) {
764 dt->mod_name = new_name;
769 mutex_lock(&ddebug_lock);
770 list_add_tail(&dt->link, &ddebug_tables);
771 mutex_unlock(&ddebug_lock);
774 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
777 EXPORT_SYMBOL_GPL(ddebug_add_module);
779 static void ddebug_table_free(struct ddebug_table *dt)
781 list_del_init(&dt->link);
787 * Called in response to a module being unloaded. Removes
788 * any ddebug_table's which point at the module.
790 int ddebug_remove_module(const char *mod_name)
792 struct ddebug_table *dt, *nextdt;
796 pr_info("removing module \"%s\"\n", mod_name);
798 mutex_lock(&ddebug_lock);
799 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
800 if (!strcmp(dt->mod_name, mod_name)) {
801 ddebug_table_free(dt);
805 mutex_unlock(&ddebug_lock);
808 EXPORT_SYMBOL_GPL(ddebug_remove_module);
810 static void ddebug_remove_all_tables(void)
812 mutex_lock(&ddebug_lock);
813 while (!list_empty(&ddebug_tables)) {
814 struct ddebug_table *dt = list_entry(ddebug_tables.next,
817 ddebug_table_free(dt);
819 mutex_unlock(&ddebug_lock);
822 static __initdata int ddebug_init_success;
824 static int __init dynamic_debug_init_debugfs(void)
826 struct dentry *dir, *file;
828 if (!ddebug_init_success)
831 dir = debugfs_create_dir("dynamic_debug", NULL);
834 file = debugfs_create_file("control", 0644, dir, NULL,
843 static int __init dynamic_debug_init(void)
845 struct _ddebug *iter, *iter_start;
846 const char *modname = NULL;
850 if (__start___verbose != __stop___verbose) {
851 iter = __start___verbose;
852 modname = iter->modname;
854 for (; iter < __stop___verbose; iter++) {
855 if (strcmp(modname, iter->modname)) {
856 ret = ddebug_add_module(iter_start, n, modname);
860 modname = iter->modname;
865 ret = ddebug_add_module(iter_start, n, modname);
868 /* ddebug_query boot param got passed -> set it up */
869 if (ddebug_setup_string[0] != '\0') {
870 ret = ddebug_exec_query(ddebug_setup_string);
872 pr_warn("Invalid ddebug boot param %s",
873 ddebug_setup_string);
875 pr_info("ddebug initialized with string %s",
876 ddebug_setup_string);
881 ddebug_remove_all_tables();
883 ddebug_init_success = 1;
886 /* Allow early initialization for boot messages via boot param */
887 arch_initcall(dynamic_debug_init);
888 /* Debugfs setup must be done later */
889 module_init(dynamic_debug_init_debugfs);