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 struct _ddebug *ddebugs;
52 unsigned int first_lineno, last_lineno;
56 struct ddebug_table *table;
60 static DEFINE_MUTEX(ddebug_lock);
61 static LIST_HEAD(ddebug_tables);
62 static int verbose = 0;
63 module_param(verbose, int, 0644);
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;
156 pr_info("changed %s:%d [%s]%s %s\n",
157 dp->filename, dp->lineno,
158 dt->mod_name, dp->function,
159 ddebug_describe_flags(dp, flagbuf,
163 mutex_unlock(&ddebug_lock);
165 if (!nfound && verbose)
166 pr_info("no matches for query\n");
170 * Split the buffer `buf' into space-separated words.
171 * Handles simple " and ' quoting, i.e. without nested,
172 * embedded or escaped \". Return the number of words
175 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
182 /* Skip leading whitespace */
183 buf = skip_spaces(buf);
185 break; /* oh, it was trailing whitespace */
187 /* find `end' of word, whitespace separated or quoted */
188 if (*buf == '"' || *buf == '\'') {
190 for (end = buf ; *end && *end != quote ; end++)
193 return -EINVAL; /* unclosed quote */
195 for (end = buf ; *end && !isspace(*end) ; end++)
200 /* `buf' is start of word, `end' is one past its end */
201 if (nwords == maxwords)
202 return -EINVAL; /* ran out of words[] before bytes */
204 *end++ = '\0'; /* terminate the word */
205 words[nwords++] = buf;
211 pr_info("split into words:");
212 for (i = 0 ; i < nwords ; i++)
213 pr_cont(" \"%s\"", words[i]);
221 * Parse a single line number. Note that the empty string ""
222 * is treated as a special case and converted to zero, which
223 * is later treated as a "don't care" value.
225 static inline int parse_lineno(const char *str, unsigned int *val)
233 *val = simple_strtoul(str, &end, 10);
234 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
238 * Undo octal escaping in a string, inplace. This is useful to
239 * allow the user to express a query which matches a format
240 * containing embedded spaces.
242 #define isodigit(c) ((c) >= '0' && (c) <= '7')
243 static char *unescape(char *str)
254 } else if (in[1] == 't') {
258 } else if (in[1] == 'n') {
262 } else if (isodigit(in[1]) &&
265 *out++ = ((in[1] - '0')<<6) |
280 * Parse words[] as a ddebug query specification, which is a series
281 * of (keyword, value) pairs chosen from these possibilities:
283 * func <function-name>
284 * file <full-pathname>
285 * file <base-filename>
286 * module <module-name>
287 * format <escaped-string-to-find-in-format>
289 * line <first-lineno>-<last-lineno> // where either may be empty
291 static int ddebug_parse_query(char *words[], int nwords,
292 struct ddebug_query *query)
296 /* check we have an even number of words */
299 memset(query, 0, sizeof(*query));
301 for (i = 0 ; i < nwords ; i += 2) {
302 if (!strcmp(words[i], "func"))
303 query->function = words[i+1];
304 else if (!strcmp(words[i], "file"))
305 query->filename = words[i+1];
306 else if (!strcmp(words[i], "module"))
307 query->module = words[i+1];
308 else if (!strcmp(words[i], "format"))
309 query->format = unescape(words[i+1]);
310 else if (!strcmp(words[i], "line")) {
311 char *first = words[i+1];
312 char *last = strchr(first, '-');
315 if (parse_lineno(first, &query->first_lineno) < 0)
318 /* range <first>-<last> */
319 if (parse_lineno(last, &query->last_lineno) < 0)
322 query->last_lineno = query->first_lineno;
325 pr_err("unknown keyword \"%s\"\n", words[i]);
331 pr_info("q->function=\"%s\" q->filename=\"%s\" "
332 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
333 query->function, query->filename,
334 query->module, query->format, query->first_lineno,
341 * Parse `str' as a flags specification, format [-+=][p]+.
342 * Sets up *maskp and *flagsp to be used when changing the
343 * flags fields of matched _ddebug's. Returns 0 on success
346 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
362 pr_info("op='%c'\n", op);
364 for ( ; *str ; ++str) {
365 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
366 if (*str == opt_array[i].opt_char) {
367 flags |= opt_array[i].flag;
377 pr_info("flags=0x%x\n", flags);
379 /* calculate final *flagsp, *maskp according to mask and op */
395 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
399 static int ddebug_exec_query(char *query_string)
401 unsigned int flags = 0, mask = 0;
402 struct ddebug_query query;
405 char *words[MAXWORDS];
407 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
410 if (ddebug_parse_query(words, nwords-1, &query))
412 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
415 /* actually go and implement the change */
416 ddebug_change(&query, flags, mask);
420 #define PREFIX_SIZE 64
422 static int remaining(int wrote)
424 if (PREFIX_SIZE - wrote > 0)
425 return PREFIX_SIZE - wrote;
429 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
434 pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
435 if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
437 pos += snprintf(buf + pos, remaining(pos), "%s ",
440 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
441 task_pid_vnr(current));
444 if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
445 pos += snprintf(buf + pos, remaining(pos), "%s:",
447 if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
448 pos += snprintf(buf + pos, remaining(pos), "%s:",
450 if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
451 pos += snprintf(buf + pos, remaining(pos), "%d:",
453 if (pos - pos_after_tid)
454 pos += snprintf(buf + pos, remaining(pos), " ");
455 if (pos >= PREFIX_SIZE)
456 buf[PREFIX_SIZE - 1] = '\0';
461 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
465 struct va_format vaf;
466 char buf[PREFIX_SIZE];
474 res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
479 EXPORT_SYMBOL(__dynamic_pr_debug);
481 int __dynamic_dev_dbg(struct _ddebug *descriptor,
482 const struct device *dev, const char *fmt, ...)
484 struct va_format vaf;
487 char buf[PREFIX_SIZE];
495 res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
500 EXPORT_SYMBOL(__dynamic_dev_dbg);
504 int __dynamic_netdev_dbg(struct _ddebug *descriptor,
505 const struct net_device *dev, const char *fmt, ...)
507 struct va_format vaf;
510 char buf[PREFIX_SIZE];
518 res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
523 EXPORT_SYMBOL(__dynamic_netdev_dbg);
527 #define DDEBUG_STRING_SIZE 1024
528 static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
530 static __init int ddebug_setup_query(char *str)
532 if (strlen(str) >= DDEBUG_STRING_SIZE) {
533 pr_warn("ddebug boot param string too large\n");
536 strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
540 __setup("ddebug_query=", ddebug_setup_query);
543 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
544 * command text from userspace, parses and executes it.
546 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
547 size_t len, loff_t *offp)
554 /* we don't check *offp -- multiple writes() are allowed */
555 if (len > sizeof(tmpbuf)-1)
557 if (copy_from_user(tmpbuf, ubuf, len))
561 pr_info("read %d bytes from userspace\n", (int)len);
563 ret = ddebug_exec_query(tmpbuf);
572 * Set the iterator to point to the first _ddebug object
573 * and return a pointer to that first object. Returns
574 * NULL if there are no _ddebugs at all.
576 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
578 if (list_empty(&ddebug_tables)) {
583 iter->table = list_entry(ddebug_tables.next,
584 struct ddebug_table, link);
586 return &iter->table->ddebugs[iter->idx];
590 * Advance the iterator to point to the next _ddebug
591 * object from the one the iterator currently points at,
592 * and returns a pointer to the new _ddebug. Returns
593 * NULL if the iterator has seen all the _ddebugs.
595 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
597 if (iter->table == NULL)
599 if (++iter->idx == iter->table->num_ddebugs) {
600 /* iterate to next table */
602 if (list_is_last(&iter->table->link, &ddebug_tables)) {
606 iter->table = list_entry(iter->table->link.next,
607 struct ddebug_table, link);
609 return &iter->table->ddebugs[iter->idx];
613 * Seq_ops start method. Called at the start of every
614 * read() call from userspace. Takes the ddebug_lock and
615 * seeks the seq_file's iterator to the given position.
617 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
619 struct ddebug_iter *iter = m->private;
624 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
626 mutex_lock(&ddebug_lock);
629 return SEQ_START_TOKEN;
632 dp = ddebug_iter_first(iter);
633 while (dp != NULL && --n > 0)
634 dp = ddebug_iter_next(iter);
639 * Seq_ops next method. Called several times within a read()
640 * call from userspace, with ddebug_lock held. Walks to the
641 * next _ddebug object with a special case for the header line.
643 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
645 struct ddebug_iter *iter = m->private;
649 pr_info("called m=%p p=%p *pos=%lld\n",
650 m, p, (unsigned long long)*pos);
652 if (p == SEQ_START_TOKEN)
653 dp = ddebug_iter_first(iter);
655 dp = ddebug_iter_next(iter);
661 * Seq_ops show method. Called several times within a read()
662 * call from userspace, with ddebug_lock held. Formats the
663 * current _ddebug as a single human-readable line, with a
664 * special case for the header line.
666 static int ddebug_proc_show(struct seq_file *m, void *p)
668 struct ddebug_iter *iter = m->private;
669 struct _ddebug *dp = p;
673 pr_info("called m=%p p=%p\n", m, p);
675 if (p == SEQ_START_TOKEN) {
677 "# filename:lineno [module]function flags format\n");
681 seq_printf(m, "%s:%u [%s]%s %s \"",
682 dp->filename, dp->lineno,
683 iter->table->mod_name, dp->function,
684 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
685 seq_escape(m, dp->format, "\t\r\n\"");
692 * Seq_ops stop method. Called at the end of each read()
693 * call from userspace. Drops ddebug_lock.
695 static void ddebug_proc_stop(struct seq_file *m, void *p)
698 pr_info("called m=%p p=%p\n", m, p);
699 mutex_unlock(&ddebug_lock);
702 static const struct seq_operations ddebug_proc_seqops = {
703 .start = ddebug_proc_start,
704 .next = ddebug_proc_next,
705 .show = ddebug_proc_show,
706 .stop = ddebug_proc_stop
710 * File_ops->open method for <debugfs>/dynamic_debug/control. Does
711 * the seq_file setup dance, and also creates an iterator to walk the
712 * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
713 * files where it's not needed, as doing so simplifies the ->release
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;
768 mutex_lock(&ddebug_lock);
769 list_add_tail(&dt->link, &ddebug_tables);
770 mutex_unlock(&ddebug_lock);
773 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
776 EXPORT_SYMBOL_GPL(ddebug_add_module);
778 static void ddebug_table_free(struct ddebug_table *dt)
780 list_del_init(&dt->link);
786 * Called in response to a module being unloaded. Removes
787 * any ddebug_table's which point at the module.
789 int ddebug_remove_module(const char *mod_name)
791 struct ddebug_table *dt, *nextdt;
795 pr_info("removing module \"%s\"\n", mod_name);
797 mutex_lock(&ddebug_lock);
798 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
799 if (!strcmp(dt->mod_name, mod_name)) {
800 ddebug_table_free(dt);
804 mutex_unlock(&ddebug_lock);
807 EXPORT_SYMBOL_GPL(ddebug_remove_module);
809 static void ddebug_remove_all_tables(void)
811 mutex_lock(&ddebug_lock);
812 while (!list_empty(&ddebug_tables)) {
813 struct ddebug_table *dt = list_entry(ddebug_tables.next,
816 ddebug_table_free(dt);
818 mutex_unlock(&ddebug_lock);
821 static __initdata int ddebug_init_success;
823 static int __init dynamic_debug_init_debugfs(void)
825 struct dentry *dir, *file;
827 if (!ddebug_init_success)
830 dir = debugfs_create_dir("dynamic_debug", NULL);
833 file = debugfs_create_file("control", 0644, dir, NULL,
842 static int __init dynamic_debug_init(void)
844 struct _ddebug *iter, *iter_start;
845 const char *modname = NULL;
849 if (__start___verbose != __stop___verbose) {
850 iter = __start___verbose;
851 modname = iter->modname;
853 for (; iter < __stop___verbose; iter++) {
854 if (strcmp(modname, iter->modname)) {
855 ret = ddebug_add_module(iter_start, n, modname);
859 modname = iter->modname;
864 ret = ddebug_add_module(iter_start, n, modname);
867 /* ddebug_query boot param got passed -> set it up */
868 if (ddebug_setup_string[0] != '\0') {
869 ret = ddebug_exec_query(ddebug_setup_string);
871 pr_warn("Invalid ddebug boot param %s",
872 ddebug_setup_string);
874 pr_info("ddebug initialized with string %s",
875 ddebug_setup_string);
880 ddebug_remove_all_tables();
882 ddebug_init_success = 1;
885 /* Allow early initialization for boot messages via boot param */
886 arch_initcall(dynamic_debug_init);
887 /* Debugfs setup must be done later */
888 module_init(dynamic_debug_init_debugfs);