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/mutex.h>
18 #include <linux/seq_file.h>
19 #include <linux/ctype.h>
20 #include <linux/dynamic_debug.h>
21 #include <linux/debugfs.h>
22 #include <linux/slab.h>
23 #include <linux/hardirq.h>
24 #include <linux/sched.h>
25 #include <linux/netdevice.h>
27 extern struct _ddebug __start___verbose[];
28 extern struct _ddebug __stop___verbose[];
31 struct list_head link;
33 unsigned int num_ddebugs;
34 struct _ddebug *ddebugs;
42 unsigned int first_lineno, last_lineno;
46 struct ddebug_table *table;
50 static DEFINE_MUTEX(ddebug_lock);
51 static LIST_HEAD(ddebug_tables);
52 static int verbose = 0;
53 module_param(verbose, int, 0644);
55 /* Return the last part of a pathname */
56 static inline const char *basename(const char *path)
58 const char *tail = strrchr(path, '/');
59 return tail ? tail+1 : path;
62 /* Return the path relative to source root */
63 static inline const char *trim_prefix(const char *path)
65 int skip = strlen(__FILE__) - strlen("lib/dynamic_debug.c");
67 if (strncmp(path, __FILE__, skip))
68 skip = 0; /* prefix mismatch, don't skip */
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' },
79 { _DPRINTK_FLAGS_NONE, '_' },
82 /* format a string into buf[] which describes the _ddebug's flags */
83 static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
90 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
91 if (dp->flags & opt_array[i].flag)
92 *p++ = opt_array[i].opt_char;
100 #define vpr_info(fmt, ...) \
101 if (verbose) do { pr_info(fmt, ##__VA_ARGS__); } while (0)
103 #define vpr_info_dq(q, msg) \
105 /* trim last char off format print */ \
106 vpr_info("%s: func=\"%s\" file=\"%s\" " \
107 "module=\"%s\" format=\"%.*s\" " \
110 q->function ? q->function : "", \
111 q->filename ? q->filename : "", \
112 q->module ? q->module : "", \
113 (int)(q->format ? strlen(q->format) - 1 : 0), \
114 q->format ? q->format : "", \
115 q->first_lineno, q->last_lineno); \
119 * Search the tables for _ddebug's which match the given `query' and
120 * apply the `flags' and `mask' to them. Returns number of matching
121 * callsites, normally the same as number of changes. If verbose,
122 * logs the changes. Takes ddebug_lock.
124 static int ddebug_change(const struct ddebug_query *query,
125 unsigned int flags, unsigned int mask)
128 struct ddebug_table *dt;
129 unsigned int newflags;
130 unsigned int nfound = 0;
133 /* search for matching ddebugs */
134 mutex_lock(&ddebug_lock);
135 list_for_each_entry(dt, &ddebug_tables, link) {
137 /* match against the module name */
138 if (query->module && strcmp(query->module, dt->mod_name))
141 for (i = 0 ; i < dt->num_ddebugs ; i++) {
142 struct _ddebug *dp = &dt->ddebugs[i];
144 /* match against the source filename */
145 if (query->filename &&
146 strcmp(query->filename, dp->filename) &&
147 strcmp(query->filename, basename(dp->filename)) &&
148 strcmp(query->filename, trim_prefix(dp->filename)))
151 /* match against the function */
152 if (query->function &&
153 strcmp(query->function, dp->function))
156 /* match against the format */
158 !strstr(dp->format, query->format))
161 /* match against the line number range */
162 if (query->first_lineno &&
163 dp->lineno < query->first_lineno)
165 if (query->last_lineno &&
166 dp->lineno > query->last_lineno)
171 newflags = (dp->flags & mask) | flags;
172 if (newflags == dp->flags)
174 dp->flags = newflags;
175 vpr_info("changed %s:%d [%s]%s =%s\n",
176 trim_prefix(dp->filename), dp->lineno,
177 dt->mod_name, dp->function,
178 ddebug_describe_flags(dp, flagbuf,
182 mutex_unlock(&ddebug_lock);
184 if (!nfound && verbose)
185 pr_info("no matches for query\n");
191 * Split the buffer `buf' into space-separated words.
192 * Handles simple " and ' quoting, i.e. without nested,
193 * embedded or escaped \". Return the number of words
196 static int ddebug_tokenize(char *buf, char *words[], int maxwords)
203 /* Skip leading whitespace */
204 buf = skip_spaces(buf);
206 break; /* oh, it was trailing whitespace */
208 break; /* token starts comment, skip rest of line */
210 /* find `end' of word, whitespace separated or quoted */
211 if (*buf == '"' || *buf == '\'') {
213 for (end = buf ; *end && *end != quote ; end++)
216 return -EINVAL; /* unclosed quote */
218 for (end = buf ; *end && !isspace(*end) ; end++)
223 /* `buf' is start of word, `end' is one past its end */
224 if (nwords == maxwords)
225 return -EINVAL; /* ran out of words[] before bytes */
227 *end++ = '\0'; /* terminate the word */
228 words[nwords++] = buf;
234 pr_info("split into words:");
235 for (i = 0 ; i < nwords ; i++)
236 pr_cont(" \"%s\"", words[i]);
244 * Parse a single line number. Note that the empty string ""
245 * is treated as a special case and converted to zero, which
246 * is later treated as a "don't care" value.
248 static inline int parse_lineno(const char *str, unsigned int *val)
256 *val = simple_strtoul(str, &end, 10);
257 return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
261 * Undo octal escaping in a string, inplace. This is useful to
262 * allow the user to express a query which matches a format
263 * containing embedded spaces.
265 #define isodigit(c) ((c) >= '0' && (c) <= '7')
266 static char *unescape(char *str)
277 } else if (in[1] == 't') {
281 } else if (in[1] == 'n') {
285 } else if (isodigit(in[1]) &&
288 *out++ = ((in[1] - '0')<<6) |
302 static int check_set(const char **dest, char *src, char *name)
308 pr_err("match-spec:%s val:%s overridden by %s",
316 * Parse words[] as a ddebug query specification, which is a series
317 * of (keyword, value) pairs chosen from these possibilities:
319 * func <function-name>
320 * file <full-pathname>
321 * file <base-filename>
322 * module <module-name>
323 * format <escaped-string-to-find-in-format>
325 * line <first-lineno>-<last-lineno> // where either may be empty
327 * Only 1 of each type is allowed.
328 * Returns 0 on success, <0 on error.
330 static int ddebug_parse_query(char *words[], int nwords,
331 struct ddebug_query *query, const char *modname)
336 /* check we have an even number of words */
339 memset(query, 0, sizeof(*query));
342 /* support $modname.dyndbg=<multiple queries> */
343 query->module = modname;
345 for (i = 0 ; i < nwords ; i += 2) {
346 if (!strcmp(words[i], "func"))
347 rc = check_set(&query->function, words[i+1], "func");
348 else if (!strcmp(words[i], "file"))
349 rc = check_set(&query->filename, words[i+1], "file");
350 else if (!strcmp(words[i], "module"))
351 rc = check_set(&query->module, words[i+1], "module");
352 else if (!strcmp(words[i], "format"))
353 rc = check_set(&query->format, unescape(words[i+1]),
355 else if (!strcmp(words[i], "line")) {
356 char *first = words[i+1];
357 char *last = strchr(first, '-');
358 if (query->first_lineno || query->last_lineno) {
359 pr_err("match-spec:line given 2 times\n");
364 if (parse_lineno(first, &query->first_lineno) < 0)
367 /* range <first>-<last> */
368 if (parse_lineno(last, &query->last_lineno)
369 < query->first_lineno) {
370 pr_err("last-line < 1st-line\n");
374 query->last_lineno = query->first_lineno;
377 pr_err("unknown keyword \"%s\"\n", words[i]);
383 vpr_info_dq(query, "parsed");
388 * Parse `str' as a flags specification, format [-+=][p]+.
389 * Sets up *maskp and *flagsp to be used when changing the
390 * flags fields of matched _ddebug's. Returns 0 on success
393 static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
408 vpr_info("op='%c'\n", op);
410 for ( ; *str ; ++str) {
411 for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
412 if (*str == opt_array[i].opt_char) {
413 flags |= opt_array[i].flag;
420 vpr_info("flags=0x%x\n", flags);
422 /* calculate final *flagsp, *maskp according to mask and op */
437 vpr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
441 static int ddebug_exec_query(char *query_string, const char *modname)
443 unsigned int flags = 0, mask = 0;
444 struct ddebug_query query;
447 char *words[MAXWORDS];
449 nwords = ddebug_tokenize(query_string, words, MAXWORDS);
452 if (ddebug_parse_query(words, nwords-1, &query, modname))
454 if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
457 /* actually go and implement the change */
458 nfound = ddebug_change(&query, flags, mask);
459 vpr_info_dq((&query), (nfound) ? "applied" : "no-match");
464 /* handle multiple queries in query string, continue on error, return
465 last error or number of matching callsites. Module name is either
466 in param (for boot arg) or perhaps in query string.
468 static int ddebug_exec_queries(char *query, const char *modname)
471 int i, errs = 0, exitcode = 0, rc, nfound = 0;
473 for (i = 0; query; query = split) {
474 split = strpbrk(query, ";\n");
478 query = skip_spaces(query);
479 if (!query || !*query || *query == '#')
482 vpr_info("query %d: \"%s\"\n", i, query);
484 rc = ddebug_exec_query(query, modname);
492 vpr_info("processed %d queries, with %d matches, %d errs\n",
500 #define PREFIX_SIZE 64
502 static int remaining(int wrote)
504 if (PREFIX_SIZE - wrote > 0)
505 return PREFIX_SIZE - wrote;
509 static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
514 pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
515 if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
517 pos += snprintf(buf + pos, remaining(pos), "%s ",
520 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
521 task_pid_vnr(current));
524 if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
525 pos += snprintf(buf + pos, remaining(pos), "%s:",
527 if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
528 pos += snprintf(buf + pos, remaining(pos), "%s:",
530 if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
531 pos += snprintf(buf + pos, remaining(pos), "%d:",
533 if (pos - pos_after_tid)
534 pos += snprintf(buf + pos, remaining(pos), " ");
535 if (pos >= PREFIX_SIZE)
536 buf[PREFIX_SIZE - 1] = '\0';
541 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
545 struct va_format vaf;
546 char buf[PREFIX_SIZE];
554 res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
559 EXPORT_SYMBOL(__dynamic_pr_debug);
561 int __dynamic_dev_dbg(struct _ddebug *descriptor,
562 const struct device *dev, const char *fmt, ...)
564 struct va_format vaf;
567 char buf[PREFIX_SIZE];
575 res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
580 EXPORT_SYMBOL(__dynamic_dev_dbg);
584 int __dynamic_netdev_dbg(struct _ddebug *descriptor,
585 const struct net_device *dev, const char *fmt, ...)
587 struct va_format vaf;
590 char buf[PREFIX_SIZE];
598 res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
603 EXPORT_SYMBOL(__dynamic_netdev_dbg);
607 #define DDEBUG_STRING_SIZE 1024
608 static __initdata char ddebug_setup_string[DDEBUG_STRING_SIZE];
610 static __init int ddebug_setup_query(char *str)
612 if (strlen(str) >= DDEBUG_STRING_SIZE) {
613 pr_warn("ddebug boot param string too large\n");
616 strlcpy(ddebug_setup_string, str, DDEBUG_STRING_SIZE);
620 __setup("ddebug_query=", ddebug_setup_query);
623 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
624 * command text from userspace, parses and executes it.
626 #define USER_BUF_PAGE 4096
627 static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
628 size_t len, loff_t *offp)
635 if (len > USER_BUF_PAGE - 1) {
636 pr_warn("expected <%d bytes into control\n", USER_BUF_PAGE);
639 tmpbuf = kmalloc(len + 1, GFP_KERNEL);
642 if (copy_from_user(tmpbuf, ubuf, len)) {
647 vpr_info("read %d bytes from userspace\n", (int)len);
649 ret = ddebug_exec_queries(tmpbuf, NULL);
659 * Set the iterator to point to the first _ddebug object
660 * and return a pointer to that first object. Returns
661 * NULL if there are no _ddebugs at all.
663 static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
665 if (list_empty(&ddebug_tables)) {
670 iter->table = list_entry(ddebug_tables.next,
671 struct ddebug_table, link);
673 return &iter->table->ddebugs[iter->idx];
677 * Advance the iterator to point to the next _ddebug
678 * object from the one the iterator currently points at,
679 * and returns a pointer to the new _ddebug. Returns
680 * NULL if the iterator has seen all the _ddebugs.
682 static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
684 if (iter->table == NULL)
686 if (++iter->idx == iter->table->num_ddebugs) {
687 /* iterate to next table */
689 if (list_is_last(&iter->table->link, &ddebug_tables)) {
693 iter->table = list_entry(iter->table->link.next,
694 struct ddebug_table, link);
696 return &iter->table->ddebugs[iter->idx];
700 * Seq_ops start method. Called at the start of every
701 * read() call from userspace. Takes the ddebug_lock and
702 * seeks the seq_file's iterator to the given position.
704 static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
706 struct ddebug_iter *iter = m->private;
710 vpr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
712 mutex_lock(&ddebug_lock);
715 return SEQ_START_TOKEN;
718 dp = ddebug_iter_first(iter);
719 while (dp != NULL && --n > 0)
720 dp = ddebug_iter_next(iter);
725 * Seq_ops next method. Called several times within a read()
726 * call from userspace, with ddebug_lock held. Walks to the
727 * next _ddebug object with a special case for the header line.
729 static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
731 struct ddebug_iter *iter = m->private;
734 vpr_info("called m=%p p=%p *pos=%lld\n",
735 m, p, (unsigned long long)*pos);
737 if (p == SEQ_START_TOKEN)
738 dp = ddebug_iter_first(iter);
740 dp = ddebug_iter_next(iter);
746 * Seq_ops show method. Called several times within a read()
747 * call from userspace, with ddebug_lock held. Formats the
748 * current _ddebug as a single human-readable line, with a
749 * special case for the header line.
751 static int ddebug_proc_show(struct seq_file *m, void *p)
753 struct ddebug_iter *iter = m->private;
754 struct _ddebug *dp = p;
757 vpr_info("called m=%p p=%p\n", m, p);
759 if (p == SEQ_START_TOKEN) {
761 "# filename:lineno [module]function flags format\n");
765 seq_printf(m, "%s:%u [%s]%s =%s \"",
766 trim_prefix(dp->filename), dp->lineno,
767 iter->table->mod_name, dp->function,
768 ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
769 seq_escape(m, dp->format, "\t\r\n\"");
776 * Seq_ops stop method. Called at the end of each read()
777 * call from userspace. Drops ddebug_lock.
779 static void ddebug_proc_stop(struct seq_file *m, void *p)
781 vpr_info("called m=%p p=%p\n", m, p);
782 mutex_unlock(&ddebug_lock);
785 static const struct seq_operations ddebug_proc_seqops = {
786 .start = ddebug_proc_start,
787 .next = ddebug_proc_next,
788 .show = ddebug_proc_show,
789 .stop = ddebug_proc_stop
793 * File_ops->open method for <debugfs>/dynamic_debug/control. Does
794 * the seq_file setup dance, and also creates an iterator to walk the
795 * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
796 * files where it's not needed, as doing so simplifies the ->release
799 static int ddebug_proc_open(struct inode *inode, struct file *file)
801 struct ddebug_iter *iter;
804 vpr_info("called\n");
806 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
810 err = seq_open(file, &ddebug_proc_seqops);
815 ((struct seq_file *) file->private_data)->private = iter;
819 static const struct file_operations ddebug_proc_fops = {
820 .owner = THIS_MODULE,
821 .open = ddebug_proc_open,
824 .release = seq_release_private,
825 .write = ddebug_proc_write
829 * Allocate a new ddebug_table for the given module
830 * and add it to the global list.
832 int ddebug_add_module(struct _ddebug *tab, unsigned int n,
835 struct ddebug_table *dt;
838 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
841 new_name = kstrdup(name, GFP_KERNEL);
842 if (new_name == NULL) {
846 dt->mod_name = new_name;
850 mutex_lock(&ddebug_lock);
851 list_add_tail(&dt->link, &ddebug_tables);
852 mutex_unlock(&ddebug_lock);
854 vpr_info("%u debug prints in module %s\n", n, dt->mod_name);
857 EXPORT_SYMBOL_GPL(ddebug_add_module);
859 /* helper for ddebug_dyndbg_(boot|module)_param_cb */
860 static int ddebug_dyndbg_param_cb(char *param, char *val,
861 const char *modname, int on_err)
865 sep = strchr(param, '.');
867 /* needed only for ddebug_dyndbg_boot_param_cb */
872 if (strcmp(param, "dyndbg"))
873 return on_err; /* determined by caller */
875 ddebug_exec_queries((val ? val : "+p"), modname);
877 return 0; /* query failure shouldnt stop module load */
880 /* handle both dyndbg and $module.dyndbg params at boot */
881 static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
884 vpr_info("%s=\"%s\"\n", param, val);
885 return ddebug_dyndbg_param_cb(param, val, NULL, 0);
889 * modprobe foo finds foo.params in boot-args, strips "foo.", and
890 * passes them to load_module(). This callback gets unknown params,
891 * processes dyndbg params, rejects others.
893 int ddebug_dyndbg_module_param_cb(char *param, char *val, const char *module)
895 vpr_info("module: %s %s=\"%s\"\n", module, param, val);
896 return ddebug_dyndbg_param_cb(param, val, module, -ENOENT);
899 static void ddebug_table_free(struct ddebug_table *dt)
901 list_del_init(&dt->link);
907 * Called in response to a module being unloaded. Removes
908 * any ddebug_table's which point at the module.
910 int ddebug_remove_module(const char *mod_name)
912 struct ddebug_table *dt, *nextdt;
915 vpr_info("removing module \"%s\"\n", mod_name);
917 mutex_lock(&ddebug_lock);
918 list_for_each_entry_safe(dt, nextdt, &ddebug_tables, link) {
919 if (!strcmp(dt->mod_name, mod_name)) {
920 ddebug_table_free(dt);
924 mutex_unlock(&ddebug_lock);
927 EXPORT_SYMBOL_GPL(ddebug_remove_module);
929 static void ddebug_remove_all_tables(void)
931 mutex_lock(&ddebug_lock);
932 while (!list_empty(&ddebug_tables)) {
933 struct ddebug_table *dt = list_entry(ddebug_tables.next,
936 ddebug_table_free(dt);
938 mutex_unlock(&ddebug_lock);
941 static __initdata int ddebug_init_success;
943 static int __init dynamic_debug_init_debugfs(void)
945 struct dentry *dir, *file;
947 if (!ddebug_init_success)
950 dir = debugfs_create_dir("dynamic_debug", NULL);
953 file = debugfs_create_file("control", 0644, dir, NULL,
962 static int __init dynamic_debug_init(void)
964 struct _ddebug *iter, *iter_start;
965 const char *modname = NULL;
968 int n = 0, entries = 0, modct = 0;
969 int verbose_bytes = 0;
971 if (__start___verbose == __stop___verbose) {
972 pr_warn("_ddebug table is empty in a "
973 "CONFIG_DYNAMIC_DEBUG build");
976 iter = __start___verbose;
977 modname = iter->modname;
979 for (; iter < __stop___verbose; iter++) {
981 verbose_bytes += strlen(iter->modname) + strlen(iter->function)
982 + strlen(iter->filename) + strlen(iter->format);
984 if (strcmp(modname, iter->modname)) {
986 ret = ddebug_add_module(iter_start, n, modname);
990 modname = iter->modname;
995 ret = ddebug_add_module(iter_start, n, modname);
999 ddebug_init_success = 1;
1000 vpr_info("%d modules, %d entries and %d bytes in ddebug tables,"
1001 " %d bytes in (readonly) verbose section\n",
1002 modct, entries, (int)( modct * sizeof(struct ddebug_table)),
1003 verbose_bytes + (int)(__stop___verbose - __start___verbose));
1005 /* apply ddebug_query boot param, dont unload tables on err */
1006 if (ddebug_setup_string[0] != '\0') {
1007 pr_warn("ddebug_query param name is deprecated,"
1008 " change it to dyndbg\n");
1009 ret = ddebug_exec_queries(ddebug_setup_string, NULL);
1011 pr_warn("Invalid ddebug boot param %s",
1012 ddebug_setup_string);
1014 pr_info("%d changes by ddebug_query\n", ret);
1016 /* now that ddebug tables are loaded, process all boot args
1017 * again to find and activate queries given in dyndbg params.
1018 * While this has already been done for known boot params, it
1019 * ignored the unknown ones (dyndbg in particular). Reusing
1020 * parse_args avoids ad-hoc parsing. This will also attempt
1021 * to activate queries for not-yet-loaded modules, which is
1022 * slightly noisy if verbose, but harmless.
1024 cmdline = kstrdup(saved_command_line, GFP_KERNEL);
1025 parse_args("dyndbg params", cmdline, NULL,
1026 0, 0, 0, &ddebug_dyndbg_boot_param_cb);
1031 ddebug_remove_all_tables();
1034 /* Allow early initialization for boot messages via boot param */
1035 early_initcall(dynamic_debug_init);
1037 /* Debugfs setup must be done later */
1038 fs_initcall(dynamic_debug_init_debugfs);