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
&& strcmp(query
->module
, dt
->mod_name
))
121 for (i
= 0 ; i
< dt
->num_ddebugs
; i
++) {
122 struct _ddebug
*dp
= &dt
->ddebugs
[i
];
124 /* match against the source filename */
125 if (query
->filename
&&
126 strcmp(query
->filename
, dp
->filename
) &&
127 strcmp(query
->filename
, basename(dp
->filename
)))
130 /* match against the function */
131 if (query
->function
&&
132 strcmp(query
->function
, dp
->function
))
135 /* match against the format */
137 !strstr(dp
->format
, query
->format
))
140 /* match against the line number range */
141 if (query
->first_lineno
&&
142 dp
->lineno
< query
->first_lineno
)
144 if (query
->last_lineno
&&
145 dp
->lineno
> query
->last_lineno
)
150 newflags
= (dp
->flags
& mask
) | flags
;
151 if (newflags
== dp
->flags
)
153 dp
->flags
= newflags
;
155 pr_info("changed %s:%d [%s]%s %s\n",
156 dp
->filename
, dp
->lineno
,
157 dt
->mod_name
, dp
->function
,
158 ddebug_describe_flags(dp
, flagbuf
,
162 mutex_unlock(&ddebug_lock
);
164 if (!nfound
&& verbose
)
165 pr_info("no matches for query\n");
169 * Split the buffer `buf' into space-separated words.
170 * Handles simple " and ' quoting, i.e. without nested,
171 * embedded or escaped \". Return the number of words
174 static int ddebug_tokenize(char *buf
, char *words
[], int maxwords
)
181 /* Skip leading whitespace */
182 buf
= skip_spaces(buf
);
184 break; /* oh, it was trailing whitespace */
186 /* find `end' of word, whitespace separated or quoted */
187 if (*buf
== '"' || *buf
== '\'') {
189 for (end
= buf
; *end
&& *end
!= quote
; end
++)
192 return -EINVAL
; /* unclosed quote */
194 for (end
= buf
; *end
&& !isspace(*end
) ; end
++)
199 /* `buf' is start of word, `end' is one past its end */
200 if (nwords
== maxwords
)
201 return -EINVAL
; /* ran out of words[] before bytes */
203 *end
++ = '\0'; /* terminate the word */
204 words
[nwords
++] = buf
;
210 pr_info("split into words:");
211 for (i
= 0 ; i
< nwords
; i
++)
212 pr_cont(" \"%s\"", words
[i
]);
220 * Parse a single line number. Note that the empty string ""
221 * is treated as a special case and converted to zero, which
222 * is later treated as a "don't care" value.
224 static inline int parse_lineno(const char *str
, unsigned int *val
)
232 *val
= simple_strtoul(str
, &end
, 10);
233 return end
== NULL
|| end
== str
|| *end
!= '\0' ? -EINVAL
: 0;
237 * Undo octal escaping in a string, inplace. This is useful to
238 * allow the user to express a query which matches a format
239 * containing embedded spaces.
241 #define isodigit(c) ((c) >= '0' && (c) <= '7')
242 static char *unescape(char *str
)
253 } else if (in
[1] == 't') {
257 } else if (in
[1] == 'n') {
261 } else if (isodigit(in
[1]) &&
264 *out
++ = ((in
[1] - '0')<<6) |
279 * Parse words[] as a ddebug query specification, which is a series
280 * of (keyword, value) pairs chosen from these possibilities:
282 * func <function-name>
283 * file <full-pathname>
284 * file <base-filename>
285 * module <module-name>
286 * format <escaped-string-to-find-in-format>
288 * line <first-lineno>-<last-lineno> // where either may be empty
290 static int ddebug_parse_query(char *words
[], int nwords
,
291 struct ddebug_query
*query
)
295 /* check we have an even number of words */
298 memset(query
, 0, sizeof(*query
));
300 for (i
= 0 ; i
< nwords
; i
+= 2) {
301 if (!strcmp(words
[i
], "func"))
302 query
->function
= words
[i
+1];
303 else if (!strcmp(words
[i
], "file"))
304 query
->filename
= words
[i
+1];
305 else if (!strcmp(words
[i
], "module"))
306 query
->module
= words
[i
+1];
307 else if (!strcmp(words
[i
], "format"))
308 query
->format
= unescape(words
[i
+1]);
309 else if (!strcmp(words
[i
], "line")) {
310 char *first
= words
[i
+1];
311 char *last
= strchr(first
, '-');
314 if (parse_lineno(first
, &query
->first_lineno
) < 0)
317 /* range <first>-<last> */
318 if (parse_lineno(last
, &query
->last_lineno
) < 0)
321 query
->last_lineno
= query
->first_lineno
;
324 pr_err("unknown keyword \"%s\"\n", words
[i
]);
330 pr_info("q->function=\"%s\" q->filename=\"%s\" "
331 "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
332 query
->function
, query
->filename
,
333 query
->module
, query
->format
, query
->first_lineno
,
340 * Parse `str' as a flags specification, format [-+=][p]+.
341 * Sets up *maskp and *flagsp to be used when changing the
342 * flags fields of matched _ddebug's. Returns 0 on success
345 static int ddebug_parse_flags(const char *str
, unsigned int *flagsp
,
361 pr_info("op='%c'\n", op
);
363 for ( ; *str
; ++str
) {
364 for (i
= ARRAY_SIZE(opt_array
) - 1; i
>= 0; i
--) {
365 if (*str
== opt_array
[i
].opt_char
) {
366 flags
|= opt_array
[i
].flag
;
376 pr_info("flags=0x%x\n", flags
);
378 /* calculate final *flagsp, *maskp according to mask and op */
394 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp
, *maskp
);
398 static int ddebug_exec_query(char *query_string
)
400 unsigned int flags
= 0, mask
= 0;
401 struct ddebug_query query
;
404 char *words
[MAXWORDS
];
406 nwords
= ddebug_tokenize(query_string
, words
, MAXWORDS
);
409 if (ddebug_parse_query(words
, nwords
-1, &query
))
411 if (ddebug_parse_flags(words
[nwords
-1], &flags
, &mask
))
414 /* actually go and implement the change */
415 ddebug_change(&query
, flags
, mask
);
419 #define PREFIX_SIZE 64
421 static int remaining(int wrote
)
423 if (PREFIX_SIZE
- wrote
> 0)
424 return PREFIX_SIZE
- wrote
;
428 static char *dynamic_emit_prefix(const struct _ddebug
*desc
, char *buf
)
433 pos
+= snprintf(buf
+ pos
, remaining(pos
), "%s", KERN_DEBUG
);
434 if (desc
->flags
& _DPRINTK_FLAGS_INCL_TID
) {
436 pos
+= snprintf(buf
+ pos
, remaining(pos
), "%s ",
439 pos
+= snprintf(buf
+ pos
, remaining(pos
), "[%d] ",
440 task_pid_vnr(current
));
443 if (desc
->flags
& _DPRINTK_FLAGS_INCL_MODNAME
)
444 pos
+= snprintf(buf
+ pos
, remaining(pos
), "%s:",
446 if (desc
->flags
& _DPRINTK_FLAGS_INCL_FUNCNAME
)
447 pos
+= snprintf(buf
+ pos
, remaining(pos
), "%s:",
449 if (desc
->flags
& _DPRINTK_FLAGS_INCL_LINENO
)
450 pos
+= snprintf(buf
+ pos
, remaining(pos
), "%d:",
452 if (pos
- pos_after_tid
)
453 pos
+= snprintf(buf
+ pos
, remaining(pos
), " ");
454 if (pos
>= PREFIX_SIZE
)
455 buf
[PREFIX_SIZE
- 1] = '\0';
460 int __dynamic_pr_debug(struct _ddebug
*descriptor
, const char *fmt
, ...)
464 struct va_format vaf
;
465 char buf
[PREFIX_SIZE
];
473 res
= printk("%s%pV", dynamic_emit_prefix(descriptor
, buf
), &vaf
);
478 EXPORT_SYMBOL(__dynamic_pr_debug
);
480 int __dynamic_dev_dbg(struct _ddebug
*descriptor
,
481 const struct device
*dev
, const char *fmt
, ...)
483 struct va_format vaf
;
486 char buf
[PREFIX_SIZE
];
494 res
= __dev_printk(dynamic_emit_prefix(descriptor
, buf
), dev
, &vaf
);
499 EXPORT_SYMBOL(__dynamic_dev_dbg
);
503 int __dynamic_netdev_dbg(struct _ddebug
*descriptor
,
504 const struct net_device
*dev
, const char *fmt
, ...)
506 struct va_format vaf
;
509 char buf
[PREFIX_SIZE
];
517 res
= __netdev_printk(dynamic_emit_prefix(descriptor
, buf
), dev
, &vaf
);
522 EXPORT_SYMBOL(__dynamic_netdev_dbg
);
526 #define DDEBUG_STRING_SIZE 1024
527 static __initdata
char ddebug_setup_string
[DDEBUG_STRING_SIZE
];
529 static __init
int ddebug_setup_query(char *str
)
531 if (strlen(str
) >= DDEBUG_STRING_SIZE
) {
532 pr_warn("ddebug boot param string too large\n");
535 strlcpy(ddebug_setup_string
, str
, DDEBUG_STRING_SIZE
);
539 __setup("ddebug_query=", ddebug_setup_query
);
542 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
543 * command text from userspace, parses and executes it.
545 static ssize_t
ddebug_proc_write(struct file
*file
, const char __user
*ubuf
,
546 size_t len
, loff_t
*offp
)
553 /* we don't check *offp -- multiple writes() are allowed */
554 if (len
> sizeof(tmpbuf
)-1)
556 if (copy_from_user(tmpbuf
, ubuf
, len
))
560 pr_info("read %d bytes from userspace\n", (int)len
);
562 ret
= ddebug_exec_query(tmpbuf
);
571 * Set the iterator to point to the first _ddebug object
572 * and return a pointer to that first object. Returns
573 * NULL if there are no _ddebugs at all.
575 static struct _ddebug
*ddebug_iter_first(struct ddebug_iter
*iter
)
577 if (list_empty(&ddebug_tables
)) {
582 iter
->table
= list_entry(ddebug_tables
.next
,
583 struct ddebug_table
, link
);
585 return &iter
->table
->ddebugs
[iter
->idx
];
589 * Advance the iterator to point to the next _ddebug
590 * object from the one the iterator currently points at,
591 * and returns a pointer to the new _ddebug. Returns
592 * NULL if the iterator has seen all the _ddebugs.
594 static struct _ddebug
*ddebug_iter_next(struct ddebug_iter
*iter
)
596 if (iter
->table
== NULL
)
598 if (++iter
->idx
== iter
->table
->num_ddebugs
) {
599 /* iterate to next table */
601 if (list_is_last(&iter
->table
->link
, &ddebug_tables
)) {
605 iter
->table
= list_entry(iter
->table
->link
.next
,
606 struct ddebug_table
, link
);
608 return &iter
->table
->ddebugs
[iter
->idx
];
612 * Seq_ops start method. Called at the start of every
613 * read() call from userspace. Takes the ddebug_lock and
614 * seeks the seq_file's iterator to the given position.
616 static void *ddebug_proc_start(struct seq_file
*m
, loff_t
*pos
)
618 struct ddebug_iter
*iter
= m
->private;
623 pr_info("called m=%p *pos=%lld\n", m
, (unsigned long long)*pos
);
625 mutex_lock(&ddebug_lock
);
628 return SEQ_START_TOKEN
;
631 dp
= ddebug_iter_first(iter
);
632 while (dp
!= NULL
&& --n
> 0)
633 dp
= ddebug_iter_next(iter
);
638 * Seq_ops next method. Called several times within a read()
639 * call from userspace, with ddebug_lock held. Walks to the
640 * next _ddebug object with a special case for the header line.
642 static void *ddebug_proc_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
644 struct ddebug_iter
*iter
= m
->private;
648 pr_info("called m=%p p=%p *pos=%lld\n",
649 m
, p
, (unsigned long long)*pos
);
651 if (p
== SEQ_START_TOKEN
)
652 dp
= ddebug_iter_first(iter
);
654 dp
= ddebug_iter_next(iter
);
660 * Seq_ops show method. Called several times within a read()
661 * call from userspace, with ddebug_lock held. Formats the
662 * current _ddebug as a single human-readable line, with a
663 * special case for the header line.
665 static int ddebug_proc_show(struct seq_file
*m
, void *p
)
667 struct ddebug_iter
*iter
= m
->private;
668 struct _ddebug
*dp
= p
;
672 pr_info("called m=%p p=%p\n", m
, p
);
674 if (p
== SEQ_START_TOKEN
) {
676 "# filename:lineno [module]function flags format\n");
680 seq_printf(m
, "%s:%u [%s]%s %s \"",
681 dp
->filename
, dp
->lineno
,
682 iter
->table
->mod_name
, dp
->function
,
683 ddebug_describe_flags(dp
, flagsbuf
, sizeof(flagsbuf
)));
684 seq_escape(m
, dp
->format
, "\t\r\n\"");
691 * Seq_ops stop method. Called at the end of each read()
692 * call from userspace. Drops ddebug_lock.
694 static void ddebug_proc_stop(struct seq_file
*m
, void *p
)
697 pr_info("called m=%p p=%p\n", m
, p
);
698 mutex_unlock(&ddebug_lock
);
701 static const struct seq_operations ddebug_proc_seqops
= {
702 .start
= ddebug_proc_start
,
703 .next
= ddebug_proc_next
,
704 .show
= ddebug_proc_show
,
705 .stop
= ddebug_proc_stop
709 * File_ops->open method for <debugfs>/dynamic_debug/control. Does
710 * the seq_file setup dance, and also creates an iterator to walk the
711 * _ddebugs. Note that we create a seq_file always, even for O_WRONLY
712 * files where it's not needed, as doing so simplifies the ->release
715 static int ddebug_proc_open(struct inode
*inode
, struct file
*file
)
717 struct ddebug_iter
*iter
;
723 iter
= kzalloc(sizeof(*iter
), GFP_KERNEL
);
727 err
= seq_open(file
, &ddebug_proc_seqops
);
732 ((struct seq_file
*) file
->private_data
)->private = iter
;
736 static const struct file_operations ddebug_proc_fops
= {
737 .owner
= THIS_MODULE
,
738 .open
= ddebug_proc_open
,
741 .release
= seq_release_private
,
742 .write
= ddebug_proc_write
746 * Allocate a new ddebug_table for the given module
747 * and add it to the global list.
749 int ddebug_add_module(struct _ddebug
*tab
, unsigned int n
,
752 struct ddebug_table
*dt
;
755 dt
= kzalloc(sizeof(*dt
), GFP_KERNEL
);
758 new_name
= kstrdup(name
, GFP_KERNEL
);
759 if (new_name
== NULL
) {
763 dt
->mod_name
= new_name
;
767 mutex_lock(&ddebug_lock
);
768 list_add_tail(&dt
->link
, &ddebug_tables
);
769 mutex_unlock(&ddebug_lock
);
772 pr_info("%u debug prints in module %s\n", n
, dt
->mod_name
);
775 EXPORT_SYMBOL_GPL(ddebug_add_module
);
777 static void ddebug_table_free(struct ddebug_table
*dt
)
779 list_del_init(&dt
->link
);
785 * Called in response to a module being unloaded. Removes
786 * any ddebug_table's which point at the module.
788 int ddebug_remove_module(const char *mod_name
)
790 struct ddebug_table
*dt
, *nextdt
;
794 pr_info("removing module \"%s\"\n", mod_name
);
796 mutex_lock(&ddebug_lock
);
797 list_for_each_entry_safe(dt
, nextdt
, &ddebug_tables
, link
) {
798 if (!strcmp(dt
->mod_name
, mod_name
)) {
799 ddebug_table_free(dt
);
803 mutex_unlock(&ddebug_lock
);
806 EXPORT_SYMBOL_GPL(ddebug_remove_module
);
808 static void ddebug_remove_all_tables(void)
810 mutex_lock(&ddebug_lock
);
811 while (!list_empty(&ddebug_tables
)) {
812 struct ddebug_table
*dt
= list_entry(ddebug_tables
.next
,
815 ddebug_table_free(dt
);
817 mutex_unlock(&ddebug_lock
);
820 static __initdata
int ddebug_init_success
;
822 static int __init
dynamic_debug_init_debugfs(void)
824 struct dentry
*dir
, *file
;
826 if (!ddebug_init_success
)
829 dir
= debugfs_create_dir("dynamic_debug", NULL
);
832 file
= debugfs_create_file("control", 0644, dir
, NULL
,
841 static int __init
dynamic_debug_init(void)
843 struct _ddebug
*iter
, *iter_start
;
844 const char *modname
= NULL
;
848 if (__start___verbose
!= __stop___verbose
) {
849 iter
= __start___verbose
;
850 modname
= iter
->modname
;
852 for (; iter
< __stop___verbose
; iter
++) {
853 if (strcmp(modname
, iter
->modname
)) {
854 ret
= ddebug_add_module(iter_start
, n
, modname
);
858 modname
= iter
->modname
;
863 ret
= ddebug_add_module(iter_start
, n
, modname
);
866 /* ddebug_query boot param got passed -> set it up */
867 if (ddebug_setup_string
[0] != '\0') {
868 ret
= ddebug_exec_query(ddebug_setup_string
);
870 pr_warn("Invalid ddebug boot param %s",
871 ddebug_setup_string
);
873 pr_info("ddebug initialized with string %s",
874 ddebug_setup_string
);
879 ddebug_remove_all_tables();
881 ddebug_init_success
= 1;
884 /* Allow early initialization for boot messages via boot param */
885 arch_initcall(dynamic_debug_init
);
886 /* Debugfs setup must be done later */
887 module_init(dynamic_debug_init_debugfs
);