blob: dcdade39e47fa4aebf0745c651cd389e18889e3a [file] [log] [blame]
Jason Barone9d376f2009-02-05 11:51:38 -05001/*
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.
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +010010 * Copyright (C) 2011 Bart Van Assche. All Rights Reserved.
Jason Barone9d376f2009-02-05 11:51:38 -050011 */
12
Joe Perches4ad275e2011-08-11 14:36:33 -040013#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
14
Jason Barone9d376f2009-02-05 11:51:38 -050015#include <linux/kernel.h>
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/kallsyms.h>
Jason Barone9d376f2009-02-05 11:51:38 -050019#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>
André Goddard Rosae7d28602009-12-14 18:01:06 -080026#include <linux/string.h>
Jason Barone9d376f2009-02-05 11:51:38 -050027#include <linux/uaccess.h>
28#include <linux/dynamic_debug.h>
29#include <linux/debugfs.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090030#include <linux/slab.h>
Jason Baron52159d92010-09-17 11:09:17 -040031#include <linux/jump_label.h>
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +010032#include <linux/hardirq.h>
Greg Kroah-Hartmane8d97922011-02-03 15:59:58 -080033#include <linux/sched.h>
Joe Perchescbc46632011-08-11 14:36:21 -040034#include <linux/device.h>
Jason Baronffa10cb2011-08-11 14:36:48 -040035#include <linux/netdevice.h>
Jason Barone9d376f2009-02-05 11:51:38 -050036
37extern struct _ddebug __start___verbose[];
38extern struct _ddebug __stop___verbose[];
39
Jason Barone9d376f2009-02-05 11:51:38 -050040struct ddebug_table {
41 struct list_head link;
42 char *mod_name;
43 unsigned int num_ddebugs;
Jason Barone9d376f2009-02-05 11:51:38 -050044 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
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +010071static 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
Jason Barone9d376f2009-02-05 11:51:38 -050079/* 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;
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +010084 int i;
Jason Barone9d376f2009-02-05 11:51:38 -050085
86 BUG_ON(maxlen < 4);
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +010087 for (i = 0; i < ARRAY_SIZE(opt_array); ++i)
88 if (dp->flags & opt_array[i].flag)
89 *p++ = opt_array[i].opt_char;
Jason Barone9d376f2009-02-05 11:51:38 -050090 if (p == buf)
91 *p++ = '-';
92 *p = '\0';
93
94 return buf;
95}
96
97/*
Jason Barone9d376f2009-02-05 11:51:38 -050098 * 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;
Jason Barone9d376f2009-02-05 11:51:38 -0500153 dp->flags = newflags;
Jason Baron2d75af22011-01-07 13:36:58 -0500154 if (newflags)
155 dp->enabled = 1;
156 else
157 dp->enabled = 0;
Jason Barone9d376f2009-02-05 11:51:38 -0500158 if (verbose)
Joe Perches4ad275e2011-08-11 14:36:33 -0400159 pr_info("changed %s:%d [%s]%s %s\n",
Jason Barone9d376f2009-02-05 11:51:38 -0500160 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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400169 pr_info("no matches for query\n");
Jason Barone9d376f2009-02-05 11:51:38 -0500170}
171
172/*
Jason Barone9d376f2009-02-05 11:51:38 -0500173 * Split the buffer `buf' into space-separated words.
Greg Banks9898abb2009-02-06 12:54:26 +1100174 * Handles simple " and ' quoting, i.e. without nested,
175 * embedded or escaped \". Return the number of words
176 * or <0 on error.
Jason Barone9d376f2009-02-05 11:51:38 -0500177 */
178static int ddebug_tokenize(char *buf, char *words[], int maxwords)
179{
180 int nwords = 0;
181
Greg Banks9898abb2009-02-06 12:54:26 +1100182 while (*buf) {
183 char *end;
184
185 /* Skip leading whitespace */
André Goddard Rosae7d28602009-12-14 18:01:06 -0800186 buf = skip_spaces(buf);
Greg Banks9898abb2009-02-06 12:54:26 +1100187 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 }
Jason Barone9d376f2009-02-05 11:51:38 -0500211
212 if (verbose) {
213 int i;
Joe Perches4ad275e2011-08-11 14:36:33 -0400214 pr_info("split into words:");
Jason Barone9d376f2009-02-05 11:51:38 -0500215 for (i = 0 ; i < nwords ; i++)
Joe Perches4ad275e2011-08-11 14:36:33 -0400216 pr_cont(" \"%s\"", words[i]);
217 pr_cont("\n");
Jason Barone9d376f2009-02-05 11:51:38 -0500218 }
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400329 pr_err("unknown keyword \"%s\"\n", words[i]);
Jason Barone9d376f2009-02-05 11:51:38 -0500330 return -EINVAL;
331 }
332 }
333
334 if (verbose)
Joe Perches4ad275e2011-08-11 14:36:33 -0400335 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,
Jason Barone9d376f2009-02-05 11:51:38 -0500338 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;
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100354 int op = '=', i;
Jason Barone9d376f2009-02-05 11:51:38 -0500355
356 switch (*str) {
357 case '+':
358 case '-':
359 case '=':
360 op = *str++;
361 break;
362 default:
363 return -EINVAL;
364 }
365 if (verbose)
Joe Perches4ad275e2011-08-11 14:36:33 -0400366 pr_info("op='%c'\n", op);
Jason Barone9d376f2009-02-05 11:51:38 -0500367
368 for ( ; *str ; ++str) {
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100369 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 }
Jason Barone9d376f2009-02-05 11:51:38 -0500374 }
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100375 if (i < 0)
376 return -EINVAL;
Jason Barone9d376f2009-02-05 11:51:38 -0500377 }
378 if (flags == 0)
379 return -EINVAL;
380 if (verbose)
Joe Perches4ad275e2011-08-11 14:36:33 -0400381 pr_info("flags=0x%x\n", flags);
Jason Barone9d376f2009-02-05 11:51:38 -0500382
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400399 pr_info("*flagsp=0x%x *maskp=0x%x\n", *flagsp, *maskp);
Jason Barone9d376f2009-02-05 11:51:38 -0500400 return 0;
401}
402
Thomas Renningerfd89cfb2010-08-06 16:11:01 +0200403static 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
Jason Baron431625d2011-10-04 14:13:19 -0700424#define PREFIX_SIZE 64
425
426static int remaining(int wrote)
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100427{
Jason Baron431625d2011-10-04 14:13:19 -0700428 if (PREFIX_SIZE - wrote > 0)
429 return PREFIX_SIZE - wrote;
430 return 0;
431}
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100432
Jason Baron431625d2011-10-04 14:13:19 -0700433static 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) {
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100440 if (in_interrupt())
Jason Baron431625d2011-10-04 14:13:19 -0700441 pos += snprintf(buf + pos, remaining(pos), "%s ",
442 "<intr>");
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100443 else
Jason Baron431625d2011-10-04 14:13:19 -0700444 pos += snprintf(buf + pos, remaining(pos), "[%d] ",
445 task_pid_vnr(current));
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100446 }
Jason Baron431625d2011-10-04 14:13:19 -0700447 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';
Joe Perches6c2140e2011-08-11 14:36:25 -0400460
Jason Baron431625d2011-10-04 14:13:19 -0700461 return buf;
Joe Perches6c2140e2011-08-11 14:36:25 -0400462}
463
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100464int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
465{
466 va_list args;
467 int res;
Jason Baron431625d2011-10-04 14:13:19 -0700468 struct va_format vaf;
469 char buf[PREFIX_SIZE];
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100470
471 BUG_ON(!descriptor);
472 BUG_ON(!fmt);
473
474 va_start(args, fmt);
Jason Baron431625d2011-10-04 14:13:19 -0700475 vaf.fmt = fmt;
476 vaf.va = &args;
477 res = printk("%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);
Bart Van Assche8ba6ebf52011-01-23 17:17:24 +0100478 va_end(args);
479
480 return res;
481}
482EXPORT_SYMBOL(__dynamic_pr_debug);
483
Joe Perchescbc46632011-08-11 14:36:21 -0400484int __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;
Jason Baron431625d2011-10-04 14:13:19 -0700490 char buf[PREFIX_SIZE];
Joe Perchescbc46632011-08-11 14:36:21 -0400491
492 BUG_ON(!descriptor);
493 BUG_ON(!fmt);
494
495 va_start(args, fmt);
Joe Perchescbc46632011-08-11 14:36:21 -0400496 vaf.fmt = fmt;
497 vaf.va = &args;
Jason Baron431625d2011-10-04 14:13:19 -0700498 res = __dev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
Joe Perchescbc46632011-08-11 14:36:21 -0400499 va_end(args);
500
501 return res;
502}
503EXPORT_SYMBOL(__dynamic_dev_dbg);
504
Jason Baron0feefd92011-10-04 14:13:22 -0700505#ifdef CONFIG_NET
506
Jason Baronffa10cb2011-08-11 14:36:48 -0400507int __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;
Jason Baron431625d2011-10-04 14:13:19 -0700513 char buf[PREFIX_SIZE];
Jason Baronffa10cb2011-08-11 14:36:48 -0400514
515 BUG_ON(!descriptor);
516 BUG_ON(!fmt);
517
518 va_start(args, fmt);
Jason Baronffa10cb2011-08-11 14:36:48 -0400519 vaf.fmt = fmt;
520 vaf.va = &args;
Jason Baron431625d2011-10-04 14:13:19 -0700521 res = __netdev_printk(dynamic_emit_prefix(descriptor, buf), dev, &vaf);
Jason Baronffa10cb2011-08-11 14:36:48 -0400522 va_end(args);
523
524 return res;
525}
526EXPORT_SYMBOL(__dynamic_netdev_dbg);
527
Jason Baron0feefd92011-10-04 14:13:22 -0700528#endif
529
Thomas Renningera648ec02010-08-06 16:11:02 +0200530static __initdata char ddebug_setup_string[1024];
531static __init int ddebug_setup_query(char *str)
532{
533 if (strlen(str) >= 1024) {
Joe Perches4ad275e2011-08-11 14:36:33 -0400534 pr_warn("ddebug boot param string too large\n");
Thomas Renningera648ec02010-08-06 16:11:02 +0200535 return 0;
536 }
537 strcpy(ddebug_setup_string, str);
538 return 1;
539}
540
541__setup("ddebug_query=", ddebug_setup_query);
542
Jason Barone9d376f2009-02-05 11:51:38 -0500543/*
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{
Jason Barone9d376f2009-02-05 11:51:38 -0500550 char tmpbuf[256];
Thomas Renningerfd89cfb2010-08-06 16:11:01 +0200551 int ret;
Jason Barone9d376f2009-02-05 11:51:38 -0500552
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400562 pr_info("read %d bytes from userspace\n", (int)len);
Jason Barone9d376f2009-02-05 11:51:38 -0500563
Thomas Renningerfd89cfb2010-08-06 16:11:01 +0200564 ret = ddebug_exec_query(tmpbuf);
565 if (ret)
566 return ret;
Jason Barone9d376f2009-02-05 11:51:38 -0500567
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400625 pr_info("called m=%p *pos=%lld\n", m, (unsigned long long)*pos);
Jason Barone9d376f2009-02-05 11:51:38 -0500626
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400650 pr_info("called m=%p p=%p *pos=%lld\n",
651 m, p, (unsigned long long)*pos);
Jason Barone9d376f2009-02-05 11:51:38 -0500652
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400674 pr_info("called m=%p p=%p\n", m, p);
Jason Barone9d376f2009-02-05 11:51:38 -0500675
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400699 pr_info("called m=%p p=%p\n", m, p);
Jason Barone9d376f2009-02-05 11:51:38 -0500700 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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400722 pr_info("called\n");
Jason Barone9d376f2009-02-05 11:51:38 -0500723
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;
Jason Barone9d376f2009-02-05 11:51:38 -0500766 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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400773 pr_info("%u debug prints in module %s\n", n, dt->mod_name);
Jason Barone9d376f2009-02-05 11:51:38 -0500774 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 */
Yehuda Sadehff49d742010-07-03 13:07:35 +1000789int ddebug_remove_module(const char *mod_name)
Jason Barone9d376f2009-02-05 11:51:38 -0500790{
791 struct ddebug_table *dt, *nextdt;
792 int ret = -ENOENT;
793
794 if (verbose)
Joe Perches4ad275e2011-08-11 14:36:33 -0400795 pr_info("removing module \"%s\"\n", mod_name);
Jason Barone9d376f2009-02-05 11:51:38 -0500796
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
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200821static __initdata int ddebug_init_success;
822
823static int __init dynamic_debug_init_debugfs(void)
Jason Barone9d376f2009-02-05 11:51:38 -0500824{
825 struct dentry *dir, *file;
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200826
827 if (!ddebug_init_success)
828 return -ENODEV;
Jason Barone9d376f2009-02-05 11:51:38 -0500829
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 }
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200839 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
Jason Barone9d376f2009-02-05 11:51:38 -0500849 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 }
Thomas Renningera648ec02010-08-06 16:11:02 +0200866
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)
Joe Perches4ad275e2011-08-11 14:36:33 -0400871 pr_warn("Invalid ddebug boot param %s",
872 ddebug_setup_string);
Thomas Renningera648ec02010-08-06 16:11:02 +0200873 else
874 pr_info("ddebug initialized with string %s",
875 ddebug_setup_string);
Jason Barone9d376f2009-02-05 11:51:38 -0500876 }
Thomas Renningera648ec02010-08-06 16:11:02 +0200877
Jason Barone9d376f2009-02-05 11:51:38 -0500878out_free:
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200879 if (ret)
Jason Barone9d376f2009-02-05 11:51:38 -0500880 ddebug_remove_all_tables();
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200881 else
882 ddebug_init_success = 1;
Jason Barone9d376f2009-02-05 11:51:38 -0500883 return 0;
884}
Thomas Renninger6a5c0832010-08-06 16:11:03 +0200885/* 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);