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 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)
154 dp->flags = newflags;
160 pr_info("changed %s:%d [%s]%s %s\n",
161 dp->filename, dp->lineno,
162 dt->mod_name, dp->function,
163 ddebug_describe_flags(dp, flagbuf,
167 mutex_unlock(&ddebug_lock);
169 if (!nfound && verbose)
170 pr_info("no matches for query\n");
174 * Split the buffer `buf' into space-separated words.
175 * Handles simple " and ' quoting, i.e. without nested,
176 * embedded or escaped \". Return the number of words
179 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
186 /* Skip leading whitespace */
187 buf = skip_spaces(buf);
189 break; /* oh, it was trailing whitespace */
191 /* Run `end' over a word, either whitespace separated or quoted */
192 if (*buf == '"' || *buf == '\'') {
194 for (end = buf ; *end && *end != quote ; end++)
197 return -EINVAL; /* unclosed quote */
199 for (end = buf ; *end && !isspace(*end) ; end++)
203 /* Here `buf' is the start of the word, `end' is one past the end */
205 if (nwords == maxwords)
206 return -EINVAL; /* ran out of words[] before bytes */
208 *end++ = '\0'; /* terminate the word */
209 words[nwords++] = buf;
215 pr_info("split into words:");
216 for (i = 0 ; i < nwords ; i++)
217 pr_cont(" \"%s\"", words[i]);
225 * Parse a single line number. Note that the empty string ""
226 * is treated as a special case and converted to zero, which
227 * is later treated as a "don't care" value.
229 static inline int parse_lineno(const char *str, unsigned int *val)
237 *val = simple_strtoul(str, &end, 10);
238 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
242 * Undo octal escaping in a string, inplace. This is useful to
243 * allow the user to express a query which matches a format
244 * containing embedded spaces.
246 #define isodigit(c) ((c) >= '0' && (c) <= '7')
247 static char *unescape(char *str)
258 } else if (in[1] == 't') {
262 } else if (in[1] == 'n') {
266 } else if (isodigit(in[1]) &&
269 *out++ = ((in[1] - '0')<<6) |
284 * Parse words[] as a ddebug query specification, which is a series
285 * of (keyword, value) pairs chosen from these possibilities:
287 * func <function-name>
288 * file <full-pathname>
289 * file <base-filename>
290 * module <module-name>
291 * format <escaped-string-to-find-in-format>
293 * line <first-lineno>-<last-lineno> // where either may be empty
295 static int ddebug_parse_query(char *words[], int nwords,
296 struct ddebug_query *query)
300 /* check we have an even number of words */
303 memset(query, 0, sizeof(*query));
305 for (i = 0 ; i < nwords ; i += 2) {
306 if (!strcmp(words[i], "func"))
307 query->function = words[i+1];
308 else if (!strcmp(words[i], "file"))
309 query->filename = words[i+1];
310 else if (!strcmp(words[i], "module"))
311 query->module = words[i+1];
312 else if (!strcmp(words[i], "format"))
313 query->format = unescape(words[i+1]);
314 else if (!strcmp(words[i], "line")) {
315 char *first = words[i+1];
316 char *last = strchr(first, '-');
319 if (parse_lineno(first, &query->first_lineno) < 0)
322 /* range <first>-<last> */
323 if (parse_lineno(last, &query->last_lineno) < 0)
326 query->last_lineno = query->first_lineno;
330 pr_err("unknown keyword \"%s\"\n", words[i]);
336 pr_info("q->function=\"%s\" q->filename=\"%s\" "
337 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
338 query->function, query->filename,
339 query->module, query->format, query->first_lineno,
346 * Parse `str' as a flags specification, format [-+=][p]+.
347 * Sets up *maskp and *flagsp to be used when changing the
348 * flags fields of matched _ddebug's. Returns 0 on success
351 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
367 pr_info("op='%c'\n", op);
369 for ( ; *str ; ++str) {
370 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
371 if (*str == opt_array[i].opt_char) {
372 flags |= opt_array[i].flag;
382 pr_info("flags=0x%x\n", flags);
384 /* calculate final *flagsp, *maskp according to mask and op */
400 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
404 static int ddebug_exec_query(char *query_string)
406 unsigned int flags = 0, mask = 0;
407 struct ddebug_query query;
410 char *words[MAXWORDS];
412 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
415 if (ddebug_parse_query(words, nwords-1, &query))
417 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
420 /* actually go and implement the change */
421 ddebug_change(&query, flags, mask);
425 #define PREFIX_SIZE 64
427 static int remaining(int wrote)
429 if (PREFIX_SIZE - wrote > 0)
430 return PREFIX_SIZE - wrote;
434 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
439 pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
440 if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
442 pos += snprintf(buf + pos, remaining(pos), "%s ",
445 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
446 task_pid_vnr(current));
449 if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
450 pos += snprintf(buf + pos, remaining(pos), "%s:",
452 if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
453 pos += snprintf(buf + pos, remaining(pos), "%s:",
455 if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
456 pos += snprintf(buf + pos, remaining(pos), "%d:", desc->lineno);
457 if (pos - pos_after_tid)
458 pos += snprintf(buf + pos, remaining(pos), " ");
459 if (pos >= PREFIX_SIZE)
460 buf[PREFIX_SIZE - 1] = '\0';
465 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
469 struct va_format vaf;
470 char buf[PREFIX_SIZE];
478 res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
483 EXPORT_SYMBOL(__dynamic_pr_debug);
485 int __dynamic_dev_dbg(struct _ddebug *descriptor,
486 const struct device *dev, const char *fmt, ...)
488 struct va_format vaf;
491 char buf[PREFIX_SIZE];
499 res = __dev_printk(dynamic_emit_prefix(descriptor, buf), 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;
512 char buf[PREFIX_SIZE];
520 res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
525 EXPORT_SYMBOL(__dynamic_netdev_dbg);
527 static __initdata char ddebug_setup_string[1024];
528 static __init int ddebug_setup_query(char *str)
530 if (strlen(str) >= 1024) {
531 pr_warn("ddebug boot param string too large\n");
534 strcpy(ddebug_setup_string, str);
538 __setup("ddebug_query=", ddebug_setup_query);
541 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
542 * command text from userspace, parses and executes it.
544 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
545 size_t len, loff_t *offp)
552 /* we don't check *offp -- multiple writes() are allowed */
553 if (len > sizeof(tmpbuf)-1)
555 if (copy_from_user(tmpbuf, ubuf, len))
559 pr_info("read %d bytes from userspace\n", (int)len);
561 ret = ddebug_exec_query(tmpbuf);
570 * Set the iterator to point to the first _ddebug object
571 * and return a pointer to that first object. Returns
572 * NULL if there are no _ddebugs at all.
574 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
576 if (list_empty(&ddebug_tables)) {
581 iter->table = list_entry(ddebug_tables.next,
582 struct ddebug_table, link);
584 return &iter->table->ddebugs[iter->idx];
588 * Advance the iterator to point to the next _ddebug
589 * object from the one the iterator currently points at,
590 * and returns a pointer to the new _ddebug. Returns
591 * NULL if the iterator has seen all the _ddebugs.
593 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
595 if (iter->table == NULL)
597 if (++iter->idx == iter->table->num_ddebugs) {
598 /* iterate to next table */
600 if (list_is_last(&iter->table->link, &ddebug_tables)) {
604 iter->table = list_entry(iter->table->link.next,
605 struct ddebug_table, link);
607 return &iter->table->ddebugs[iter->idx];
611 * Seq_ops start method. Called at the start of every
612 * read() call from userspace. Takes the ddebug_lock and
613 * seeks the seq_file's iterator to the given position.
615 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
617 struct ddebug_iter *iter = m->private;
622 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
624 mutex_lock(&ddebug_lock);
627 return SEQ_START_TOKEN;
630 dp = ddebug_iter_first(iter);
631 while (dp != NULL && --n > 0)
632 dp = ddebug_iter_next(iter);
637 * Seq_ops next method. Called several times within a read()
638 * call from userspace, with ddebug_lock held. Walks to the
639 * next _ddebug object with a special case for the header line.
641 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
643 struct ddebug_iter *iter = m->private;
647 pr_info("called m=%p p=%p *pos=%lld\n",
648 m, p, (unsigned long long)*pos);
650 if (p == SEQ_START_TOKEN)
651 dp = ddebug_iter_first(iter);
653 dp = ddebug_iter_next(iter);
659 * Seq_ops show method. Called several times within a read()
660 * call from userspace, with ddebug_lock held. Formats the
661 * current _ddebug as a single human-readable line, with a
662 * special case for the header line.
664 static int ddebug_proc_show(struct seq_file *m, void *p)
666 struct ddebug_iter *iter = m->private;
667 struct _ddebug *dp = p;
671 pr_info("called m=%p p=%p\n", m, p);
673 if (p == SEQ_START_TOKEN) {
675 "# filename:lineno [module]function flags format\n");
679 seq_printf(m, "%s:%u [%s]%s %s \"",
680 dp->filename, dp->lineno,
681 iter->table->mod_name, dp->function,
682 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
683 seq_escape(m, dp->format, "\t\r\n\"");
690 * Seq_ops stop method. Called at the end of each read()
691 * call from userspace. Drops ddebug_lock.
693 static void ddebug_proc_stop(struct seq_file *m, void *p)
696 pr_info("called m=%p p=%p\n", m, p);
697 mutex_unlock(&ddebug_lock);
700 static const struct seq_operations ddebug_proc_seqops = {
701 .start = ddebug_proc_start,
702 .next = ddebug_proc_next,
703 .show = ddebug_proc_show,
704 .stop = ddebug_proc_stop
708 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
709 * setup dance, and also creates an iterator to walk the _ddebugs.
710 * Note that we create a seq_file always, even for O_WRONLY files
711 * where it's not needed, as doing so simplifies the ->release method.
713 static int ddebug_proc_open(struct inode *inode, struct file *file)
715 struct ddebug_iter *iter;
721 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
725 err = seq_open(file, &ddebug_proc_seqops);
730 ((struct seq_file *) file->private_data)->private = iter;
734 static const struct file_operations ddebug_proc_fops = {
735 .owner = THIS_MODULE,
736 .open = ddebug_proc_open,
739 .release = seq_release_private,
740 .write = ddebug_proc_write
744 * Allocate a new ddebug_table for the given module
745 * and add it to the global list.
747 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
750 struct ddebug_table *dt;
753 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
756 new_name = kstrdup(name, GFP_KERNEL);
757 if (new_name == NULL) {
761 dt->mod_name = new_name;
765 mutex_lock(&ddebug_lock);
766 list_add_tail(&dt->link, &ddebug_tables);
767 mutex_unlock(&ddebug_lock);
770 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
773 EXPORT_SYMBOL_GPL(ddebug_add_module);
775 static void ddebug_table_free(struct ddebug_table *dt)
777 list_del_init(&dt->link);
783 * Called in response to a module being unloaded. Removes
784 * any ddebug_table's which point at the module.
786 int ddebug_remove_module(const char *mod_name)
788 struct ddebug_table *dt, *nextdt;
792 pr_info("removing module \"%s\"\n", mod_name);
794 mutex_lock(&ddebug_lock);
795 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
796 if (!strcmp(dt->mod_name, mod_name)) {
797 ddebug_table_free(dt);
801 mutex_unlock(&ddebug_lock);
804 EXPORT_SYMBOL_GPL(ddebug_remove_module);
806 static void ddebug_remove_all_tables(void)
808 mutex_lock(&ddebug_lock);
809 while (!list_empty(&ddebug_tables)) {
810 struct ddebug_table *dt = list_entry(ddebug_tables.next,
813 ddebug_table_free(dt);
815 mutex_unlock(&ddebug_lock);
818 static __initdata int ddebug_init_success;
820 static int __init dynamic_debug_init_debugfs(void)
822 struct dentry *dir, *file;
824 if (!ddebug_init_success)
827 dir = debugfs_create_dir("dynamic_debug", NULL);
830 file = debugfs_create_file("control", 0644, dir, NULL,
839 static int __init dynamic_debug_init(void)
841 struct _ddebug *iter, *iter_start;
842 const char *modname = NULL;
846 if (__start___verbose != __stop___verbose) {
847 iter = __start___verbose;
848 modname = iter->modname;
850 for (; iter < __stop___verbose; iter++) {
851 if (strcmp(modname, iter->modname)) {
852 ret = ddebug_add_module(iter_start, n, modname);
856 modname = iter->modname;
861 ret = ddebug_add_module(iter_start, n, modname);
864 /* ddebug_query boot param got passed -> set it up */
865 if (ddebug_setup_string[0] != '\0') {
866 ret = ddebug_exec_query(ddebug_setup_string);
868 pr_warn("Invalid ddebug boot param %s",
869 ddebug_setup_string);
871 pr_info("ddebug initialized with string %s",
872 ddebug_setup_string);
877 ddebug_remove_all_tables();
879 ddebug_init_success = 1;
882 /* Allow early initialization for boot messages via boot param */
883 arch_initcall(dynamic_debug_init);
884 /* Debugfs setup must be done later */
885 module_init(dynamic_debug_init_debugfs);