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 /* Return the path relative to source root */
73 static inline const char *trim_prefix(const char *path)
75 int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");
77 if (strncmp(path, __FILE__, skip))
78 skip = 0; /* prefix mismatch, don't skip */
83 static struct { unsigned flag:8; char opt_char; } opt_array[] = {
84 { _DPRINTK_FLAGS_PRINT, 'p' },
85 { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
86 { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
87 { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
88 { _DPRINTK_FLAGS_INCL_TID, 't' },
89 { _DPRINTK_FLAGS_NONE, '_' },
92 /* format a string into buf[] which describes the _ddebug's flags */
93 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
100 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
101 if (dp->flags & opt_array[i].flag)
102 *p++ = opt_array[i].opt_char;
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 && strcmp(query->module, dt->mod_name))
133 for (i = 0 ; i < dt->num_ddebugs ; i++) {
134 struct _ddebug *dp = &dt->ddebugs[i];
136 /* match against the source filename */
137 if (query->filename &&
138 strcmp(query->filename, dp->filename) &&
139 strcmp(query->filename, basename(dp->filename)) &&
140 strcmp(query->filename, trim_prefix(dp->filename)))
143 /* match against the function */
144 if (query->function &&
145 strcmp(query->function, dp->function))
148 /* match against the format */
150 !strstr(dp->format, query->format))
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)
166 dp->flags = newflags;
168 pr_info("changed %s:%d [%s]%s =%s\n",
169 trim_prefix(dp->filename), dp->lineno,
170 dt->mod_name, dp->function,
171 ddebug_describe_flags(dp, flagbuf,
175 mutex_unlock(&ddebug_lock);
177 if (!nfound && verbose)
178 pr_info("no matches for query\n");
182 * Split the buffer `buf' into space-separated words.
183 * Handles simple " and ' quoting, i.e. without nested,
184 * embedded or escaped \". Return the number of words
187 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
194 /* Skip leading whitespace */
195 buf = skip_spaces(buf);
197 break; /* oh, it was trailing whitespace */
199 break; /* token starts comment, skip rest of line */
201 /* find `end' of word, whitespace separated or quoted */
202 if (*buf == '"' || *buf == '\'') {
204 for (end = buf ; *end && *end != quote ; end++)
207 return -EINVAL; /* unclosed quote */
209 for (end = buf ; *end && !isspace(*end) ; end++)
214 /* `buf' is start of word, `end' is one past its end */
215 if (nwords == maxwords)
216 return -EINVAL; /* ran out of words[] before bytes */
218 *end++ = '\0'; /* terminate the word */
219 words[nwords++] = buf;
225 pr_info("split into words:");
226 for (i = 0 ; i < nwords ; i++)
227 pr_cont(" \"%s\"", words[i]);
235 * Parse a single line number. Note that the empty string ""
236 * is treated as a special case and converted to zero, which
237 * is later treated as a "don't care" value.
239 static inline int parse_lineno(const char *str, unsigned int *val)
247 *val = simple_strtoul(str, &end, 10);
248 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
252 * Undo octal escaping in a string, inplace. This is useful to
253 * allow the user to express a query which matches a format
254 * containing embedded spaces.
256 #define isodigit(c) ((c) >= '0' && (c) <= '7')
257 static char *unescape(char *str)
268 } else if (in[1] == 't') {
272 } else if (in[1] == 'n') {
276 } else if (isodigit(in[1]) &&
279 *out++ = ((in[1] - '0')<<6) |
293 static int check_set(const char **dest, char *src, char *name)
299 pr_err("match-spec:%s val:%s overridden by %s",
307 * Parse words[] as a ddebug query specification, which is a series
308 * of (keyword, value) pairs chosen from these possibilities:
310 * func <function-name>
311 * file <full-pathname>
312 * file <base-filename>
313 * module <module-name>
314 * format <escaped-string-to-find-in-format>
316 * line <first-lineno>-<last-lineno> // where either may be empty
318 * Only 1 of each type is allowed.
319 * Returns 0 on success, <0 on error.
321 static int ddebug_parse_query(char *words[], int nwords,
322 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 rc = check_set(&query->function, words[i+1], "func");
335 else if (!strcmp(words[i], "file"))
336 rc = check_set(&query->filename, words[i+1], "file");
337 else if (!strcmp(words[i], "module"))
338 rc = check_set(&query->module, words[i+1], "module");
339 else if (!strcmp(words[i], "format"))
340 rc = check_set(&query->format, unescape(words[i+1]),
342 else if (!strcmp(words[i], "line")) {
343 char *first = words[i+1];
344 char *last = strchr(first, '-');
345 if (query->first_lineno || query->last_lineno) {
346 pr_err("match-spec:line given 2 times\n");
351 if (parse_lineno(first, &query->first_lineno) < 0)
354 /* range <first>-<last> */
355 if (parse_lineno(last, &query->last_lineno)
356 < query->first_lineno) {
357 pr_err("last-line < 1st-line\n");
361 query->last_lineno = query->first_lineno;
364 pr_err("unknown keyword \"%s\"\n", words[i]);
372 pr_info("q->function=\"%s\" q->filename=\"%s\" "
373 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
374 query->function, query->filename,
375 query->module, query->format, query->first_lineno,
382 * Parse `str' as a flags specification, format [-+=][p]+.
383 * Sets up *maskp and *flagsp to be used when changing the
384 * flags fields of matched _ddebug's. Returns 0 on success
387 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
403 pr_info("op='%c'\n", op);
405 for ( ; *str ; ++str) {
406 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
407 if (*str == opt_array[i].opt_char) {
408 flags |= opt_array[i].flag;
416 pr_info("flags=0x%x\n", flags);
418 /* calculate final *flagsp, *maskp according to mask and op */
434 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
438 static int ddebug_exec_query(char *query_string)
440 unsigned int flags = 0, mask = 0;
441 struct ddebug_query query;
444 char *words[MAXWORDS];
446 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
449 if (ddebug_parse_query(words, nwords-1, &query))
451 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
454 /* actually go and implement the change */
455 ddebug_change(&query, flags, mask);
459 #define PREFIX_SIZE 64
461 static int remaining(int wrote)
463 if (PREFIX_SIZE - wrote > 0)
464 return PREFIX_SIZE - wrote;
468 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
473 pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
474 if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
476 pos += snprintf(buf + pos, remaining(pos), "%s ",
479 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
480 task_pid_vnr(current));
483 if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
484 pos += snprintf(buf + pos, remaining(pos), "%s:",
486 if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
487 pos += snprintf(buf + pos, remaining(pos), "%s:",
489 if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
490 pos += snprintf(buf + pos, remaining(pos), "%d:",
492 if (pos - pos_after_tid)
493 pos += snprintf(buf + pos, remaining(pos), " ");
494 if (pos >= PREFIX_SIZE)
495 buf[PREFIX_SIZE - 1] = '\0';
500 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
504 struct va_format vaf;
505 char buf[PREFIX_SIZE];
513 res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
518 EXPORT_SYMBOL(__dynamic_pr_debug);
520 int __dynamic_dev_dbg(struct _ddebug *descriptor,
521 const struct device *dev, const char *fmt, ...)
523 struct va_format vaf;
526 char buf[PREFIX_SIZE];
534 res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
539 EXPORT_SYMBOL(__dynamic_dev_dbg);
543 int __dynamic_netdev_dbg(struct _ddebug *descriptor,
544 const struct net_device *dev, const char *fmt, ...)
546 struct va_format vaf;
549 char buf[PREFIX_SIZE];
557 res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
562 EXPORT_SYMBOL(__dynamic_netdev_dbg);
566 #define DDEBUG_STRING_SIZE 1024
567 static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
569 static __init int ddebug_setup_query(char *str)
571 if (strlen(str) >= DDEBUG_STRING_SIZE) {
572 pr_warn("ddebug boot param string too large\n");
575 strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
579 __setup("ddebug_query=", ddebug_setup_query);
582 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
583 * command text from userspace, parses and executes it.
585 #define USER_BUF_PAGE 4096
586 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
587 size_t len, loff_t *offp)
594 if (len > USER_BUF_PAGE - 1) {
595 pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
598 tmpbuf = kmalloc(len + 1, GFP_KERNEL);
601 if (copy_from_user(tmpbuf, ubuf, len)) {
607 pr_info("read %d bytes from userspace\n", (int)len);
609 ret = ddebug_exec_query(tmpbuf);
619 * Set the iterator to point to the first _ddebug object
620 * and return a pointer to that first object. Returns
621 * NULL if there are no _ddebugs at all.
623 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
625 if (list_empty(&ddebug_tables)) {
630 iter->table = list_entry(ddebug_tables.next,
631 struct ddebug_table, link);
633 return &iter->table->ddebugs[iter->idx];
637 * Advance the iterator to point to the next _ddebug
638 * object from the one the iterator currently points at,
639 * and returns a pointer to the new _ddebug. Returns
640 * NULL if the iterator has seen all the _ddebugs.
642 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
644 if (iter->table == NULL)
646 if (++iter->idx == iter->table->num_ddebugs) {
647 /* iterate to next table */
649 if (list_is_last(&iter->table->link, &ddebug_tables)) {
653 iter->table = list_entry(iter->table->link.next,
654 struct ddebug_table, link);
656 return &iter->table->ddebugs[iter->idx];
660 * Seq_ops start method. Called at the start of every
661 * read() call from userspace. Takes the ddebug_lock and
662 * seeks the seq_file's iterator to the given position.
664 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
666 struct ddebug_iter *iter = m->private;
671 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
673 mutex_lock(&ddebug_lock);
676 return SEQ_START_TOKEN;
679 dp = ddebug_iter_first(iter);
680 while (dp != NULL && --n > 0)
681 dp = ddebug_iter_next(iter);
686 * Seq_ops next method. Called several times within a read()
687 * call from userspace, with ddebug_lock held. Walks to the
688 * next _ddebug object with a special case for the header line.
690 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
692 struct ddebug_iter *iter = m->private;
696 pr_info("called m=%p p=%p *pos=%lld\n",
697 m, p, (unsigned long long)*pos);
699 if (p == SEQ_START_TOKEN)
700 dp = ddebug_iter_first(iter);
702 dp = ddebug_iter_next(iter);
708 * Seq_ops show method. Called several times within a read()
709 * call from userspace, with ddebug_lock held. Formats the
710 * current _ddebug as a single human-readable line, with a
711 * special case for the header line.
713 static int ddebug_proc_show(struct seq_file *m, void *p)
715 struct ddebug_iter *iter = m->private;
716 struct _ddebug *dp = p;
720 pr_info("called m=%p p=%p\n", m, p);
722 if (p == SEQ_START_TOKEN) {
724 "# filename:lineno [module]function flags format\n");
728 seq_printf(m, "%s:%u [%s]%s =%s \"",
729 trim_prefix(dp->filename), dp->lineno,
730 iter->table->mod_name, dp->function,
731 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
732 seq_escape(m, dp->format, "\t\r\n\"");
739 * Seq_ops stop method. Called at the end of each read()
740 * call from userspace. Drops ddebug_lock.
742 static void ddebug_proc_stop(struct seq_file *m, void *p)
745 pr_info("called m=%p p=%p\n", m, p);
746 mutex_unlock(&ddebug_lock);
749 static const struct seq_operations ddebug_proc_seqops = {
750 .start = ddebug_proc_start,
751 .next = ddebug_proc_next,
752 .show = ddebug_proc_show,
753 .stop = ddebug_proc_stop
757 * File_ops->open method for <debugfs>/dynamic_debug/control. Does
758 * the seq_file setup dance, and also creates an iterator to walk the
759 * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
760 * files where it's not needed, as doing so simplifies the ->release
763 static int ddebug_proc_open(struct inode *inode, struct file *file)
765 struct ddebug_iter *iter;
771 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
775 err = seq_open(file, &ddebug_proc_seqops);
780 ((struct seq_file *) file->private_data)->private = iter;
784 static const struct file_operations ddebug_proc_fops = {
785 .owner = THIS_MODULE,
786 .open = ddebug_proc_open,
789 .release = seq_release_private,
790 .write = ddebug_proc_write
794 * Allocate a new ddebug_table for the given module
795 * and add it to the global list.
797 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
800 struct ddebug_table *dt;
803 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
806 new_name = kstrdup(name, GFP_KERNEL);
807 if (new_name == NULL) {
811 dt->mod_name = new_name;
815 mutex_lock(&ddebug_lock);
816 list_add_tail(&dt->link, &ddebug_tables);
817 mutex_unlock(&ddebug_lock);
820 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
823 EXPORT_SYMBOL_GPL(ddebug_add_module);
825 static void ddebug_table_free(struct ddebug_table *dt)
827 list_del_init(&dt->link);
833 * Called in response to a module being unloaded. Removes
834 * any ddebug_table's which point at the module.
836 int ddebug_remove_module(const char *mod_name)
838 struct ddebug_table *dt, *nextdt;
842 pr_info("removing module \"%s\"\n", mod_name);
844 mutex_lock(&ddebug_lock);
845 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
846 if (!strcmp(dt->mod_name, mod_name)) {
847 ddebug_table_free(dt);
851 mutex_unlock(&ddebug_lock);
854 EXPORT_SYMBOL_GPL(ddebug_remove_module);
856 static void ddebug_remove_all_tables(void)
858 mutex_lock(&ddebug_lock);
859 while (!list_empty(&ddebug_tables)) {
860 struct ddebug_table *dt = list_entry(ddebug_tables.next,
863 ddebug_table_free(dt);
865 mutex_unlock(&ddebug_lock);
868 static __initdata int ddebug_init_success;
870 static int __init dynamic_debug_init_debugfs(void)
872 struct dentry *dir, *file;
874 if (!ddebug_init_success)
877 dir = debugfs_create_dir("dynamic_debug", NULL);
880 file = debugfs_create_file("control", 0644, dir, NULL,
889 static int __init dynamic_debug_init(void)
891 struct _ddebug *iter, *iter_start;
892 const char *modname = NULL;
896 if (__start___verbose == __stop___verbose) {
897 pr_warn("_ddebug table is empty in a "
898 "CONFIG_DYNAMIC_DEBUG build");
901 iter = __start___verbose;
902 modname = iter->modname;
904 for (; iter < __stop___verbose; iter++) {
905 if (strcmp(modname, iter->modname)) {
906 ret = ddebug_add_module(iter_start, n, modname);
910 modname = iter->modname;
915 ret = ddebug_add_module(iter_start, n, modname);
919 /* ddebug_query boot param got passed -> set it up */
920 if (ddebug_setup_string[0] != '\0') {
921 ret = ddebug_exec_query(ddebug_setup_string);
923 pr_warn("Invalid ddebug boot param %s",
924 ddebug_setup_string);
926 pr_info("ddebug initialized with string %s",
927 ddebug_setup_string);
932 ddebug_remove_all_tables();
934 ddebug_init_success = 1;
937 /* Allow early initialization for boot messages via boot param */
938 arch_initcall(dynamic_debug_init);
939 /* Debugfs setup must be done later */
940 module_init(dynamic_debug_init_debugfs);