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Inaky Perez-Gonzalezea912f42008-12-20 16:57:35 -08001/*
2 * Linux WiMAX
3 * Collection of tools to manage debug operations.
4 *
5 *
6 * Copyright (C) 2005-2007 Intel Corporation
7 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version
11 * 2 as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 * 02110-1301, USA.
22 *
23 *
24 * Don't #include this file directly, read on!
25 *
26 *
27 * EXECUTING DEBUGGING ACTIONS OR NOT
28 *
29 * The main thing this framework provides is decission power to take a
30 * debug action (like printing a message) if the current debug level
31 * allows it.
32 *
33 * The decission power is at two levels: at compile-time (what does
34 * not make it is compiled out) and at run-time. The run-time
35 * selection is done per-submodule (as they are declared by the user
36 * of the framework).
37 *
38 * A call to d_test(L) (L being the target debug level) returns true
39 * if the action should be taken because the current debug levels
40 * allow it (both compile and run time).
41 *
42 * It follows that a call to d_test() that can be determined to be
43 * always false at compile time will get the code depending on it
44 * compiled out by optimization.
45 *
46 *
47 * DEBUG LEVELS
48 *
49 * It is up to the caller to define how much a debugging level is.
50 *
51 * Convention sets 0 as "no debug" (so an action marked as debug level 0
52 * will always be taken). The increasing debug levels are used for
53 * increased verbosity.
54 *
55 *
56 * USAGE
57 *
58 * Group the code in modules and submodules inside each module [which
59 * in most cases maps to Linux modules and .c files that compose
60 * those].
61 *
62 *
63 * For each module, there is:
64 *
65 * - a MODULENAME (single word, legal C identifier)
66 *
67 * - a debug-levels.h header file that declares the list of
68 * submodules and that is included by all .c files that use
69 * the debugging tools. The file name can be anything.
70 *
71 * - some (optional) .c code to manipulate the runtime debug levels
72 * through debugfs.
73 *
74 * The debug-levels.h file would look like:
75 *
76 * #ifndef __debug_levels__h__
77 * #define __debug_levels__h__
78 *
79 * #define D_MODULENAME modulename
80 * #define D_MASTER 10
81 *
82 * #include <linux/wimax/debug.h>
83 *
84 * enum d_module {
85 * D_SUBMODULE_DECLARE(submodule_1),
86 * D_SUBMODULE_DECLARE(submodule_2),
87 * ...
88 * D_SUBMODULE_DECLARE(submodule_N)
89 * };
90 *
91 * #endif
92 *
93 * D_MASTER is the maximum compile-time debug level; any debug actions
94 * above this will be out. D_MODULENAME is the module name (legal C
95 * identifier), which has to be unique for each module (to avoid
96 * namespace collisions during linkage). Note those #defines need to
97 * be done before #including debug.h
98 *
99 * We declare N different submodules whose debug level can be
100 * independently controlled during runtime.
101 *
102 * In a .c file of the module (and only in one of them), define the
103 * following code:
104 *
105 * struct d_level D_LEVEL[] = {
106 * D_SUBMODULE_DEFINE(submodule_1),
107 * D_SUBMODULE_DEFINE(submodule_2),
108 * ...
109 * D_SUBMODULE_DEFINE(submodule_N),
110 * };
111 * size_t D_LEVEL_SIZE = ARRAY_SIZE(D_LEVEL);
112 *
113 * Externs for d_level_MODULENAME and d_level_size_MODULENAME are used
114 * and declared in this file using the D_LEVEL and D_LEVEL_SIZE macros
115 * #defined also in this file.
116 *
117 * To manipulate from user space the levels, create a debugfs dentry
118 * and then register each submodule with:
119 *
120 * result = d_level_register_debugfs("PREFIX_", submodule_X, parent);
121 * if (result < 0)
122 * goto error;
123 *
124 * Where PREFIX_ is a name of your chosing. This will create debugfs
125 * file with a single numeric value that can be use to tweak it. To
126 * remove the entires, just use debugfs_remove_recursive() on 'parent'.
127 *
128 * NOTE: remember that even if this will show attached to some
129 * particular instance of a device, the settings are *global*.
130 *
131 *
132 * On each submodule (for example, .c files), the debug infrastructure
133 * should be included like this:
134 *
135 * #define D_SUBMODULE submodule_x // matches one in debug-levels.h
136 * #include "debug-levels.h"
137 *
138 * after #including all your include files.
139 *
140 *
141 * Now you can use the d_*() macros below [d_test(), d_fnstart(),
142 * d_fnend(), d_printf(), d_dump()].
143 *
144 * If their debug level is greater than D_MASTER, they will be
145 * compiled out.
146 *
147 * If their debug level is lower or equal than D_MASTER but greater
148 * than the current debug level of their submodule, they'll be
149 * ignored.
150 *
151 * Otherwise, the action will be performed.
152 */
153#ifndef __debug__h__
154#define __debug__h__
155
156#include <linux/types.h>
157#include <linux/device.h>
158
159
160/* Backend stuff */
161
162/*
163 * Debug backend: generate a message header from a 'struct device'
164 *
165 * @head: buffer where to place the header
166 * @head_size: length of @head
167 * @dev: pointer to device used to generate a header from. If NULL,
168 * an empty ("") header is generated.
169 */
170static inline
171void __d_head(char *head, size_t head_size,
172 struct device *dev)
173{
174 if (dev == NULL)
175 head[0] = 0;
176 else if ((unsigned long)dev < 4096) {
177 printk(KERN_ERR "E: Corrupt dev %p\n", dev);
178 WARN_ON(1);
179 } else
180 snprintf(head, head_size, "%s %s: ",
Kay Sievers2c0f3e92009-03-24 16:38:23 -0700181 dev_driver_string(dev), dev_name(dev));
Inaky Perez-Gonzalezea912f42008-12-20 16:57:35 -0800182}
183
184
185/*
186 * Debug backend: log some message if debugging is enabled
187 *
188 * @l: intended debug level
189 * @tag: tag to prefix the message with
190 * @dev: 'struct device' associated to this message
191 * @f: printf-like format and arguments
192 *
193 * Note this is optimized out if it doesn't pass the compile-time
194 * check; however, it is *always* compiled. This is useful to make
195 * sure the printf-like formats and variables are always checked and
196 * they don't get bit rot if you have all the debugging disabled.
197 */
198#define _d_printf(l, tag, dev, f, a...) \
199do { \
200 char head[64]; \
201 if (!d_test(l)) \
202 break; \
203 __d_head(head, sizeof(head), dev); \
204 printk(KERN_ERR "%s%s%s: " f, head, __func__, tag, ##a); \
205} while (0)
206
207
208/*
209 * CPP sintatic sugar to generate A_B like symbol names when one of
210 * the arguments is a a preprocessor #define.
211 */
212#define __D_PASTE__(varname, modulename) varname##_##modulename
213#define __D_PASTE(varname, modulename) (__D_PASTE__(varname, modulename))
214#define _D_SUBMODULE_INDEX(_name) (D_SUBMODULE_DECLARE(_name))
215
216
217/*
218 * Store a submodule's runtime debug level and name
219 */
220struct d_level {
221 u8 level;
222 const char *name;
223};
224
225
226/*
227 * List of available submodules and their debug levels
228 *
229 * We call them d_level_MODULENAME and d_level_size_MODULENAME; the
230 * macros D_LEVEL and D_LEVEL_SIZE contain the name already for
231 * convenience.
232 *
233 * This array and the size are defined on some .c file that is part of
234 * the current module.
235 */
236#define D_LEVEL __D_PASTE(d_level, D_MODULENAME)
237#define D_LEVEL_SIZE __D_PASTE(d_level_size, D_MODULENAME)
238
239extern struct d_level D_LEVEL[];
240extern size_t D_LEVEL_SIZE;
241
242
243/*
244 * Frontend stuff
245 *
246 *
247 * Stuff you need to declare prior to using the actual "debug" actions
248 * (defined below).
249 */
250
251#ifndef D_MODULENAME
252#error D_MODULENAME is not defined in your debug-levels.h file
253/**
254 * D_MODULE - Name of the current module
255 *
256 * #define in your module's debug-levels.h, making sure it is
257 * unique. This has to be a legal C identifier.
258 */
259#define D_MODULENAME undefined_modulename
260#endif
261
262
263#ifndef D_MASTER
264#warning D_MASTER not defined, but debug.h included! [see docs]
265/**
266 * D_MASTER - Compile time maximum debug level
267 *
268 * #define in your debug-levels.h file to the maximum debug level the
269 * runtime code will be allowed to have. This allows you to provide a
270 * main knob.
271 *
272 * Anything above that level will be optimized out of the compile.
273 *
274 * Defaults to zero (no debug code compiled in).
275 *
276 * Maximum one definition per module (at the debug-levels.h file).
277 */
278#define D_MASTER 0
279#endif
280
281#ifndef D_SUBMODULE
282#error D_SUBMODULE not defined, but debug.h included! [see docs]
283/**
284 * D_SUBMODULE - Name of the current submodule
285 *
286 * #define in your submodule .c file before #including debug-levels.h
287 * to the name of the current submodule as previously declared and
288 * defined with D_SUBMODULE_DECLARE() (in your module's
289 * debug-levels.h) and D_SUBMODULE_DEFINE().
290 *
291 * This is used to provide runtime-control over the debug levels.
292 *
293 * Maximum one per .c file! Can be shared among different .c files
294 * (meaning they belong to the same submodule categorization).
295 */
296#define D_SUBMODULE undefined_module
297#endif
298
299
300/**
301 * D_SUBMODULE_DECLARE - Declare a submodule for runtime debug level control
302 *
303 * @_name: name of the submodule, restricted to the chars that make up a
304 * valid C identifier ([a-zA-Z0-9_]).
305 *
306 * Declare in the module's debug-levels.h header file as:
307 *
308 * enum d_module {
309 * D_SUBMODULE_DECLARE(submodule_1),
310 * D_SUBMODULE_DECLARE(submodule_2),
311 * D_SUBMODULE_DECLARE(submodule_3),
312 * };
313 *
314 * Some corresponding .c file needs to have a matching
315 * D_SUBMODULE_DEFINE().
316 */
317#define D_SUBMODULE_DECLARE(_name) __D_SUBMODULE_##_name
318
319
320/**
321 * D_SUBMODULE_DEFINE - Define a submodule for runtime debug level control
322 *
323 * @_name: name of the submodule, restricted to the chars that make up a
324 * valid C identifier ([a-zA-Z0-9_]).
325 *
326 * Use once per module (in some .c file) as:
327 *
328 * static
329 * struct d_level d_level_SUBMODULENAME[] = {
330 * D_SUBMODULE_DEFINE(submodule_1),
331 * D_SUBMODULE_DEFINE(submodule_2),
332 * D_SUBMODULE_DEFINE(submodule_3),
333 * };
334 * size_t d_level_size_SUBDMODULENAME = ARRAY_SIZE(d_level_SUBDMODULENAME);
335 *
336 * Matching D_SUBMODULE_DECLARE()s have to be present in a
337 * debug-levels.h header file.
338 */
339#define D_SUBMODULE_DEFINE(_name) \
340[__D_SUBMODULE_##_name] = { \
341 .level = 0, \
342 .name = #_name \
343}
344
345
346
347/* The actual "debug" operations */
348
349
350/**
351 * d_test - Returns true if debugging should be enabled
352 *
353 * @l: intended debug level (unsigned)
354 *
355 * If the master debug switch is enabled and the current settings are
356 * higher or equal to the requested level, then debugging
357 * output/actions should be enabled.
358 *
359 * NOTE:
360 *
361 * This needs to be coded so that it can be evaluated in compile
362 * time; this is why the ugly BUG_ON() is placed in there, so the
363 * D_MASTER evaluation compiles all out if it is compile-time false.
364 */
365#define d_test(l) \
366({ \
367 unsigned __l = l; /* type enforcer */ \
368 (D_MASTER) >= __l \
369 && ({ \
370 BUG_ON(_D_SUBMODULE_INDEX(D_SUBMODULE) >= D_LEVEL_SIZE);\
371 D_LEVEL[_D_SUBMODULE_INDEX(D_SUBMODULE)].level >= __l; \
372 }); \
373})
374
375
376/**
377 * d_fnstart - log message at function start if debugging enabled
378 *
379 * @l: intended debug level
380 * @_dev: 'struct device' pointer, NULL if none (for context)
381 * @f: printf-like format and arguments
382 */
383#define d_fnstart(l, _dev, f, a...) _d_printf(l, " FNSTART", _dev, f, ## a)
384
385
386/**
387 * d_fnend - log message at function end if debugging enabled
388 *
389 * @l: intended debug level
390 * @_dev: 'struct device' pointer, NULL if none (for context)
391 * @f: printf-like format and arguments
392 */
393#define d_fnend(l, _dev, f, a...) _d_printf(l, " FNEND", _dev, f, ## a)
394
395
396/**
397 * d_printf - log message if debugging enabled
398 *
399 * @l: intended debug level
400 * @_dev: 'struct device' pointer, NULL if none (for context)
401 * @f: printf-like format and arguments
402 */
403#define d_printf(l, _dev, f, a...) _d_printf(l, "", _dev, f, ## a)
404
405
406/**
407 * d_dump - log buffer hex dump if debugging enabled
408 *
409 * @l: intended debug level
410 * @_dev: 'struct device' pointer, NULL if none (for context)
411 * @f: printf-like format and arguments
412 */
413#define d_dump(l, dev, ptr, size) \
414do { \
415 char head[64]; \
416 if (!d_test(l)) \
417 break; \
418 __d_head(head, sizeof(head), dev); \
419 print_hex_dump(KERN_ERR, head, 0, 16, 1, \
420 ((void *) ptr), (size), 0); \
421} while (0)
422
423
424/**
425 * Export a submodule's debug level over debugfs as PREFIXSUBMODULE
426 *
427 * @prefix: string to prefix the name with
428 * @submodule: name of submodule (not a string, just the name)
429 * @dentry: debugfs parent dentry
430 *
431 * Returns: 0 if ok, < 0 errno on error.
432 *
433 * For removing, just use debugfs_remove_recursive() on the parent.
434 */
435#define d_level_register_debugfs(prefix, name, parent) \
436({ \
437 int rc; \
438 struct dentry *fd; \
439 struct dentry *verify_parent_type = parent; \
440 fd = debugfs_create_u8( \
441 prefix #name, 0600, verify_parent_type, \
442 &(D_LEVEL[__D_SUBMODULE_ ## name].level)); \
443 rc = PTR_ERR(fd); \
444 if (IS_ERR(fd) && rc != -ENODEV) \
445 printk(KERN_ERR "%s: Can't create debugfs entry %s: " \
446 "%d\n", __func__, prefix #name, rc); \
447 else \
448 rc = 0; \
449 rc; \
450})
451
452
453#endif /* #ifndef __debug__h__ */