Root/lib/dynamic_debug.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
1/*
2 * lib/dynamic_debug.c
3 *
4 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
5 * source module.
6 *
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.
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
14
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>
36
37extern struct _ddebug __start___verbose[];
38extern struct _ddebug __stop___verbose[];
39
40struct ddebug_table {
41    struct list_head link;
42    char *mod_name;
43    unsigned int num_ddebugs;
44    struct _ddebug *ddebugs;
45};
46
47struct ddebug_query {
48    const char *filename;
49    const char *module;
50    const char *function;
51    const char *format;
52    unsigned int first_lineno, last_lineno;
53};
54
55struct ddebug_iter {
56    struct ddebug_table *table;
57    unsigned int idx;
58};
59
60static DEFINE_MUTEX(ddebug_lock);
61static LIST_HEAD(ddebug_tables);
62static int verbose = 0;
63
64/* Return the last part of a pathname */
65static inline const char *basename(const char *path)
66{
67    const char *tail = strrchr(path, '/');
68    return tail ? tail+1 : path;
69}
70
71static struct { unsigned flag:8; char opt_char; } opt_array[] = {
72    { _DPRINTK_FLAGS_PRINT, 'p' },
73    { _DPRINTK_FLAGS_INCL_MODNAME, 'm' },
74    { _DPRINTK_FLAGS_INCL_FUNCNAME, 'f' },
75    { _DPRINTK_FLAGS_INCL_LINENO, 'l' },
76    { _DPRINTK_FLAGS_INCL_TID, 't' },
77};
78
79/* format a string into buf[] which describes the _ddebug's flags */
80static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
81                    size_t maxlen)
82{
83    char *p = buf;
84    int i;
85
86    BUG_ON(maxlen < 4);
87    for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
88        if (dp->flags & opt_array[i].flag)
89            *p++ = opt_array[i].opt_char;
90    if (p == buf)
91        *p++ = '-';
92    *p = '\0';
93
94    return buf;
95}
96
97/*
98 * Search the tables for _ddebug's which match the given
99 * `query' and apply the `flags' and `mask' to them. Tells
100 * the user which ddebug's were changed, or whether none
101 * were matched.
102 */
103static void ddebug_change(const struct ddebug_query *query,
104               unsigned int flags, unsigned int mask)
105{
106    int i;
107    struct ddebug_table *dt;
108    unsigned int newflags;
109    unsigned int nfound = 0;
110    char flagbuf[8];
111
112    /* search for matching ddebugs */
113    mutex_lock(&ddebug_lock);
114    list_for_each_entry(dt, &ddebug_tables, link) {
115
116        /* match against the module name */
117        if (query->module != NULL &&
118            strcmp(query->module, dt->mod_name))
119            continue;
120
121        for (i = 0 ; i < dt->num_ddebugs ; i++) {
122            struct _ddebug *dp = &dt->ddebugs[i];
123
124            /* match against the source filename */
125            if (query->filename != NULL &&
126                strcmp(query->filename, dp->filename) &&
127                strcmp(query->filename, basename(dp->filename)))
128                continue;
129
130            /* match against the function */
131            if (query->function != NULL &&
132                strcmp(query->function, dp->function))
133                continue;
134
135            /* match against the format */
136            if (query->format != NULL &&
137                strstr(dp->format, query->format) == NULL)
138                continue;
139
140            /* match against the line number range */
141            if (query->first_lineno &&
142                dp->lineno < query->first_lineno)
143                continue;
144            if (query->last_lineno &&
145                dp->lineno > query->last_lineno)
146                continue;
147
148            nfound++;
149
150            newflags = (dp->flags & mask) | flags;
151            if (newflags == dp->flags)
152                continue;
153            dp->flags = newflags;
154            if (newflags)
155                dp->enabled = 1;
156            else
157                dp->enabled = 0;
158            if (verbose)
159                pr_info("changed %s:%d [%s]%s %s\n",
160                    dp->filename, dp->lineno,
161                    dt->mod_name, dp->function,
162                    ddebug_describe_flags(dp, flagbuf,
163                            sizeof(flagbuf)));
164        }
165    }
166    mutex_unlock(&ddebug_lock);
167
168    if (!nfound && verbose)
169        pr_info("no matches for query\n");
170}
171
172/*
173 * Split the buffer `buf' into space-separated words.
174 * Handles simple " and ' quoting, i.e. without nested,
175 * embedded or escaped \". Return the number of words
176 * or <0 on error.
177 */
178static int ddebug_tokenize(char *buf, char *words[], int maxwords)
179{
180    int nwords = 0;
181
182    while (*buf) {
183        char *end;
184
185        /* Skip leading whitespace */
186        buf = skip_spaces(buf);
187        if (!*buf)
188            break; /* oh, it was trailing whitespace */
189
190        /* Run `end' over a word, either whitespace separated or quoted */
191        if (*buf == '"' || *buf == '\'') {
192            int quote = *buf++;
193            for (end = buf ; *end && *end != quote ; end++)
194                ;
195            if (!*end)
196                return -EINVAL; /* unclosed quote */
197        } else {
198            for (end = buf ; *end && !isspace(*end) ; end++)
199                ;
200            BUG_ON(end == buf);
201        }
202        /* Here `buf' is the start of the word, `end' is one past the end */
203
204        if (nwords == maxwords)
205            return -EINVAL; /* ran out of words[] before bytes */
206        if (*end)
207            *end++ = '\0'; /* terminate the word */
208        words[nwords++] = buf;
209        buf = end;
210    }
211
212    if (verbose) {
213        int i;
214        pr_info("split into words:");
215        for (i = 0 ; i < nwords ; i++)
216            pr_cont(" \"%s\"", words[i]);
217        pr_cont("\n");
218    }
219
220    return nwords;
221}
222
223/*
224 * Parse a single line number. Note that the empty string ""
225 * is treated as a special case and converted to zero, which
226 * is later treated as a "don't care" value.
227 */
228static inline int parse_lineno(const char *str, unsigned int *val)
229{
230    char *end = NULL;
231    BUG_ON(str == NULL);
232    if (*str == '\0') {
233        *val = 0;
234        return 0;
235    }
236    *val = simple_strtoul(str, &end, 10);
237    return end == NULL || end == str || *end != '\0' ? -EINVAL : 0;
238}
239
240/*
241 * Undo octal escaping in a string, inplace. This is useful to
242 * allow the user to express a query which matches a format
243 * containing embedded spaces.
244 */
245#define isodigit(c) ((c) >= '0' && (c) <= '7')
246static char *unescape(char *str)
247{
248    char *in = str;
249    char *out = str;
250
251    while (*in) {
252        if (*in == '\\') {
253            if (in[1] == '\\') {
254                *out++ = '\\';
255                in += 2;
256                continue;
257            } else if (in[1] == 't') {
258                *out++ = '\t';
259                in += 2;
260                continue;
261            } else if (in[1] == 'n') {
262                *out++ = '\n';
263                in += 2;
264                continue;
265            } else if (isodigit(in[1]) &&
266                     isodigit(in[2]) &&
267                     isodigit(in[3])) {
268                *out++ = ((in[1] - '0')<<6) |
269                          ((in[2] - '0')<<3) |
270                          (in[3] - '0');
271                in += 4;
272                continue;
273            }
274        }
275        *out++ = *in++;
276    }
277    *out = '\0';
278
279    return str;
280}
281
282/*
283 * Parse words[] as a ddebug query specification, which is a series
284 * of (keyword, value) pairs chosen from these possibilities:
285 *
286 * func <function-name>
287 * file <full-pathname>
288 * file <base-filename>
289 * module <module-name>
290 * format <escaped-string-to-find-in-format>
291 * line <lineno>
292 * line <first-lineno>-<last-lineno> // where either may be empty
293 */
294static int ddebug_parse_query(char *words[], int nwords,
295                   struct ddebug_query *query)
296{
297    unsigned int i;
298
299    /* check we have an even number of words */
300    if (nwords % 2 != 0)
301        return -EINVAL;
302    memset(query, 0, sizeof(*query));
303
304    for (i = 0 ; i < nwords ; i += 2) {
305        if (!strcmp(words[i], "func"))
306            query->function = words[i+1];
307        else if (!strcmp(words[i], "file"))
308            query->filename = words[i+1];
309        else if (!strcmp(words[i], "module"))
310            query->module = words[i+1];
311        else if (!strcmp(words[i], "format"))
312            query->format = unescape(words[i+1]);
313        else if (!strcmp(words[i], "line")) {
314            char *first = words[i+1];
315            char *last = strchr(first, '-');
316            if (last)
317                *last++ = '\0';
318            if (parse_lineno(first, &query->first_lineno) < 0)
319                return -EINVAL;
320            if (last != NULL) {
321                /* range <first>-<last> */
322                if (parse_lineno(last, &query->last_lineno) < 0)
323                    return -EINVAL;
324            } else {
325                query->last_lineno = query->first_lineno;
326            }
327        } else {
328            if (verbose)
329                pr_err("unknown keyword \"%s\"\n", words[i]);
330            return -EINVAL;
331        }
332    }
333
334    if (verbose)
335        pr_info("q->function=\"%s\" q->filename=\"%s\" "
336            "q->module=\"%s\" q->format=\"%s\" q->lineno=%u-%u\n",
337            query->function, query->filename,
338            query->module, query->format, query->first_lineno,
339            query->last_lineno);
340
341    return 0;
342}
343
344/*
345 * Parse `str' as a flags specification, format [-+=][p]+.
346 * Sets up *maskp and *flagsp to be used when changing the
347 * flags fields of matched _ddebug's. Returns 0 on success
348 * or <0 on error.
349 */
350static int ddebug_parse_flags(const char *str, unsigned int *flagsp,
351                   unsigned int *maskp)
352{
353    unsigned flags = 0;
354    int op = '=', i;
355
356    switch (*str) {
357    case '+':
358    case '-':
359    case '=':
360        op = *str++;
361        break;
362    default:
363        return -EINVAL;
364    }
365    if (verbose)
366        pr_info("op='%c'\n", op);
367
368    for ( ; *str ; ++str) {
369        for (i = ARRAY_SIZE(opt_array) - 1; i >= 0; i--) {
370            if (*str == opt_array[i].opt_char) {
371                flags |= opt_array[i].flag;
372                break;
373            }
374        }
375        if (i < 0)
376            return -EINVAL;
377    }
378    if (flags == 0)
379        return -EINVAL;
380    if (verbose)
381        pr_info("flags=0x%x\n", flags);
382
383    /* calculate final *flagsp, *maskp according to mask and op */
384    switch (op) {
385    case '=':
386        *maskp = 0;
387        *flagsp = flags;
388        break;
389    case '+':
390        *maskp = ~0U;
391        *flagsp = flags;
392        break;
393    case '-':
394        *maskp = ~flags;
395        *flagsp = 0;
396        break;
397    }
398    if (verbose)
399        pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
400    return 0;
401}
402
403static int ddebug_exec_query(char *query_string)
404{
405    unsigned int flags = 0, mask = 0;
406    struct ddebug_query query;
407#define MAXWORDS 9
408    int nwords;
409    char *words[MAXWORDS];
410
411    nwords = ddebug_tokenize(query_string, words, MAXWORDS);
412    if (nwords <= 0)
413        return -EINVAL;
414    if (ddebug_parse_query(words, nwords-1, &query))
415        return -EINVAL;
416    if (ddebug_parse_flags(words[nwords-1], &flags, &mask))
417        return -EINVAL;
418
419    /* actually go and implement the change */
420    ddebug_change(&query, flags, mask);
421    return 0;
422}
423
424#define PREFIX_SIZE 64
425
426static int remaining(int wrote)
427{
428    if (PREFIX_SIZE - wrote > 0)
429        return PREFIX_SIZE - wrote;
430    return 0;
431}
432
433static char *dynamic_emit_prefix(const struct _ddebug *desc, char *buf)
434{
435    int pos_after_tid;
436    int pos = 0;
437
438    pos += snprintf(buf + pos, remaining(pos), "%s", KERN_DEBUG);
439    if (desc->flags & _DPRINTK_FLAGS_INCL_TID) {
440        if (in_interrupt())
441            pos += snprintf(buf + pos, remaining(pos), "%s ",
442                        "<intr>");
443        else
444            pos += snprintf(buf + pos, remaining(pos), "[%d] ",
445                        task_pid_vnr(current));
446    }
447    pos_after_tid = pos;
448    if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME)
449        pos += snprintf(buf + pos, remaining(pos), "%s:",
450                    desc->modname);
451    if (desc->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
452        pos += snprintf(buf + pos, remaining(pos), "%s:",
453                    desc->function);
454    if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO)
455        pos += snprintf(buf + pos, remaining(pos), "%d:", desc->lineno);
456    if (pos - pos_after_tid)
457        pos += snprintf(buf + pos, remaining(pos), " ");
458    if (pos >= PREFIX_SIZE)
459        buf[PREFIX_SIZE - 1] = '\0';
460
461    return buf;
462}
463
464int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
465{
466    va_list args;
467    int res;
468    struct va_format vaf;
469    char buf[PREFIX_SIZE];
470
471    BUG_ON(!descriptor);
472    BUG_ON(!fmt);
473
474    va_start(args, fmt);
475    vaf.fmt = fmt;
476    vaf.va = &args;
477    res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
478    va_end(args);
479
480    return res;
481}
482EXPORT_SYMBOL(__dynamic_pr_debug);
483
484int __dynamic_dev_dbg(struct _ddebug *descriptor,
485              const struct device *dev, const char *fmt, ...)
486{
487    struct va_format vaf;
488    va_list args;
489    int res;
490    char buf[PREFIX_SIZE];
491
492    BUG_ON(!descriptor);
493    BUG_ON(!fmt);
494
495    va_start(args, fmt);
496    vaf.fmt = fmt;
497    vaf.va = &args;
498    res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
499    va_end(args);
500
501    return res;
502}
503EXPORT_SYMBOL(__dynamic_dev_dbg);
504
505#ifdef CONFIG_NET
506
507int __dynamic_netdev_dbg(struct _ddebug *descriptor,
508              const struct net_device *dev, const char *fmt, ...)
509{
510    struct va_format vaf;
511    va_list args;
512    int res;
513    char buf[PREFIX_SIZE];
514
515    BUG_ON(!descriptor);
516    BUG_ON(!fmt);
517
518    va_start(args, fmt);
519    vaf.fmt = fmt;
520    vaf.va = &args;
521    res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
522    va_end(args);
523
524    return res;
525}
526EXPORT_SYMBOL(__dynamic_netdev_dbg);
527
528#endif
529
530static __initdata char ddebug_setup_string[1024];
531static __init int ddebug_setup_query(char *str)
532{
533    if (strlen(str) >= 1024) {
534        pr_warn("ddebug boot param string too large\n");
535        return 0;
536    }
537    strcpy(ddebug_setup_string, str);
538    return 1;
539}
540
541__setup("ddebug_query=", ddebug_setup_query);
542
543/*
544 * File_ops->write method for <debugfs>/dynamic_debug/conrol. Gathers the
545 * command text from userspace, parses and executes it.
546 */
547static ssize_t ddebug_proc_write(struct file *file, const char __user *ubuf,
548                  size_t len, loff_t *offp)
549{
550    char tmpbuf[256];
551    int ret;
552
553    if (len == 0)
554        return 0;
555    /* we don't check *offp -- multiple writes() are allowed */
556    if (len > sizeof(tmpbuf)-1)
557        return -E2BIG;
558    if (copy_from_user(tmpbuf, ubuf, len))
559        return -EFAULT;
560    tmpbuf[len] = '\0';
561    if (verbose)
562        pr_info("read %d bytes from userspace\n", (int)len);
563
564    ret = ddebug_exec_query(tmpbuf);
565    if (ret)
566        return ret;
567
568    *offp += len;
569    return len;
570}
571
572/*
573 * Set the iterator to point to the first _ddebug object
574 * and return a pointer to that first object. Returns
575 * NULL if there are no _ddebugs at all.
576 */
577static struct _ddebug *ddebug_iter_first(struct ddebug_iter *iter)
578{
579    if (list_empty(&ddebug_tables)) {
580        iter->table = NULL;
581        iter->idx = 0;
582        return NULL;
583    }
584    iter->table = list_entry(ddebug_tables.next,
585                 struct ddebug_table, link);
586    iter->idx = 0;
587    return &iter->table->ddebugs[iter->idx];
588}
589
590/*
591 * Advance the iterator to point to the next _ddebug
592 * object from the one the iterator currently points at,
593 * and returns a pointer to the new _ddebug. Returns
594 * NULL if the iterator has seen all the _ddebugs.
595 */
596static struct _ddebug *ddebug_iter_next(struct ddebug_iter *iter)
597{
598    if (iter->table == NULL)
599        return NULL;
600    if (++iter->idx == iter->table->num_ddebugs) {
601        /* iterate to next table */
602        iter->idx = 0;
603        if (list_is_last(&iter->table->link, &ddebug_tables)) {
604            iter->table = NULL;
605            return NULL;
606        }
607        iter->table = list_entry(iter->table->link.next,
608                     struct ddebug_table, link);
609    }
610    return &iter->table->ddebugs[iter->idx];
611}
612
613/*
614 * Seq_ops start method. Called at the start of every
615 * read() call from userspace. Takes the ddebug_lock and
616 * seeks the seq_file's iterator to the given position.
617 */
618static void *ddebug_proc_start(struct seq_file *m, loff_t *pos)
619{
620    struct ddebug_iter *iter = m->private;
621    struct _ddebug *dp;
622    int n = *pos;
623
624    if (verbose)
625        pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
626
627    mutex_lock(&ddebug_lock);
628
629    if (!n)
630        return SEQ_START_TOKEN;
631    if (n < 0)
632        return NULL;
633    dp = ddebug_iter_first(iter);
634    while (dp != NULL && --n > 0)
635        dp = ddebug_iter_next(iter);
636    return dp;
637}
638
639/*
640 * Seq_ops next method. Called several times within a read()
641 * call from userspace, with ddebug_lock held. Walks to the
642 * next _ddebug object with a special case for the header line.
643 */
644static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos)
645{
646    struct ddebug_iter *iter = m->private;
647    struct _ddebug *dp;
648
649    if (verbose)
650        pr_info("called m=%p p=%p *pos=%lld\n",
651            m, p, (unsigned long long)*pos);
652
653    if (p == SEQ_START_TOKEN)
654        dp = ddebug_iter_first(iter);
655    else
656        dp = ddebug_iter_next(iter);
657    ++*pos;
658    return dp;
659}
660
661/*
662 * Seq_ops show method. Called several times within a read()
663 * call from userspace, with ddebug_lock held. Formats the
664 * current _ddebug as a single human-readable line, with a
665 * special case for the header line.
666 */
667static int ddebug_proc_show(struct seq_file *m, void *p)
668{
669    struct ddebug_iter *iter = m->private;
670    struct _ddebug *dp = p;
671    char flagsbuf[8];
672
673    if (verbose)
674        pr_info("called m=%p p=%p\n", m, p);
675
676    if (p == SEQ_START_TOKEN) {
677        seq_puts(m,
678            "# filename:lineno [module]function flags format\n");
679        return 0;
680    }
681
682    seq_printf(m, "%s:%u [%s]%s %s \"",
683           dp->filename, dp->lineno,
684           iter->table->mod_name, dp->function,
685           ddebug_describe_flags(dp, flagsbuf, sizeof(flagsbuf)));
686    seq_escape(m, dp->format, "\t\r\n\"");
687    seq_puts(m, "\"\n");
688
689    return 0;
690}
691
692/*
693 * Seq_ops stop method. Called at the end of each read()
694 * call from userspace. Drops ddebug_lock.
695 */
696static void ddebug_proc_stop(struct seq_file *m, void *p)
697{
698    if (verbose)
699        pr_info("called m=%p p=%p\n", m, p);
700    mutex_unlock(&ddebug_lock);
701}
702
703static const struct seq_operations ddebug_proc_seqops = {
704    .start = ddebug_proc_start,
705    .next = ddebug_proc_next,
706    .show = ddebug_proc_show,
707    .stop = ddebug_proc_stop
708};
709
710/*
711 * File_ops->open method for <debugfs>/dynamic_debug/control. Does the seq_file
712 * setup dance, and also creates an iterator to walk the _ddebugs.
713 * Note that we create a seq_file always, even for O_WRONLY files
714 * where it's not needed, as doing so simplifies the ->release method.
715 */
716static int ddebug_proc_open(struct inode *inode, struct file *file)
717{
718    struct ddebug_iter *iter;
719    int err;
720
721    if (verbose)
722        pr_info("called\n");
723
724    iter = kzalloc(sizeof(*iter), GFP_KERNEL);
725    if (iter == NULL)
726        return -ENOMEM;
727
728    err = seq_open(file, &ddebug_proc_seqops);
729    if (err) {
730        kfree(iter);
731        return err;
732    }
733    ((struct seq_file *) file->private_data)->private = iter;
734    return 0;
735}
736
737static const struct file_operations ddebug_proc_fops = {
738    .owner = THIS_MODULE,
739    .open = ddebug_proc_open,
740    .read = seq_read,
741    .llseek = seq_lseek,
742    .release = seq_release_private,
743    .write = ddebug_proc_write
744};
745
746/*
747 * Allocate a new ddebug_table for the given module
748 * and add it to the global list.
749 */
750int ddebug_add_module(struct _ddebug *tab, unsigned int n,
751                 const char *name)
752{
753    struct ddebug_table *dt;
754    char *new_name;
755
756    dt = kzalloc(sizeof(*dt), GFP_KERNEL);
757    if (dt == NULL)
758        return -ENOMEM;
759    new_name = kstrdup(name, GFP_KERNEL);
760    if (new_name == NULL) {
761        kfree(dt);
762        return -ENOMEM;
763    }
764    dt->mod_name = new_name;
765    dt->num_ddebugs = n;
766    dt->ddebugs = tab;
767
768    mutex_lock(&ddebug_lock);
769    list_add_tail(&dt->link, &ddebug_tables);
770    mutex_unlock(&ddebug_lock);
771
772    if (verbose)
773        pr_info("%u debug prints in module %s\n", n, dt->mod_name);
774    return 0;
775}
776EXPORT_SYMBOL_GPL(ddebug_add_module);
777
778static void ddebug_table_free(struct ddebug_table *dt)
779{
780    list_del_init(&dt->link);
781    kfree(dt->mod_name);
782    kfree(dt);
783}
784
785/*
786 * Called in response to a module being unloaded. Removes
787 * any ddebug_table's which point at the module.
788 */
789int ddebug_remove_module(const char *mod_name)
790{
791    struct ddebug_table *dt, *nextdt;
792    int ret = -ENOENT;
793
794    if (verbose)
795        pr_info("removing module \"%s\"\n", mod_name);
796
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);
801            ret = 0;
802        }
803    }
804    mutex_unlock(&ddebug_lock);
805    return ret;
806}
807EXPORT_SYMBOL_GPL(ddebug_remove_module);
808
809static void ddebug_remove_all_tables(void)
810{
811    mutex_lock(&ddebug_lock);
812    while (!list_empty(&ddebug_tables)) {
813        struct ddebug_table *dt = list_entry(ddebug_tables.next,
814                              struct ddebug_table,
815                              link);
816        ddebug_table_free(dt);
817    }
818    mutex_unlock(&ddebug_lock);
819}
820
821static __initdata int ddebug_init_success;
822
823static int __init dynamic_debug_init_debugfs(void)
824{
825    struct dentry *dir, *file;
826
827    if (!ddebug_init_success)
828        return -ENODEV;
829
830    dir = debugfs_create_dir("dynamic_debug", NULL);
831    if (!dir)
832        return -ENOMEM;
833    file = debugfs_create_file("control", 0644, dir, NULL,
834                    &ddebug_proc_fops);
835    if (!file) {
836        debugfs_remove(dir);
837        return -ENOMEM;
838    }
839    return 0;
840}
841
842static int __init dynamic_debug_init(void)
843{
844    struct _ddebug *iter, *iter_start;
845    const char *modname = NULL;
846    int ret = 0;
847    int n = 0;
848
849    if (__start___verbose != __stop___verbose) {
850        iter = __start___verbose;
851        modname = iter->modname;
852        iter_start = iter;
853        for (; iter < __stop___verbose; iter++) {
854            if (strcmp(modname, iter->modname)) {
855                ret = ddebug_add_module(iter_start, n, modname);
856                if (ret)
857                    goto out_free;
858                n = 0;
859                modname = iter->modname;
860                iter_start = iter;
861            }
862            n++;
863        }
864        ret = ddebug_add_module(iter_start, n, modname);
865    }
866
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);
870        if (ret)
871            pr_warn("Invalid ddebug boot param %s",
872                ddebug_setup_string);
873        else
874            pr_info("ddebug initialized with string %s",
875                ddebug_setup_string);
876    }
877
878out_free:
879    if (ret)
880        ddebug_remove_all_tables();
881    else
882        ddebug_init_success = 1;
883    return 0;
884}
885/* Allow early initialization for boot messages via boot param */
886arch_initcall(dynamic_debug_init);
887/* Debugfs setup must be done later */
888module_init(dynamic_debug_init_debugfs);
889

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