aboutsummaryrefslogtreecommitdiffstats
path: root/lib/dynamic_printk.c
diff options
context:
space:
mode:
authorJason Baron <jbaron@redhat.com>2009-02-05 11:51:38 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-24 19:38:26 -0400
commite9d376f0fa66bd630fe27403669c6ae6c22a868f (patch)
tree6eadef32eb421647ae98d88341b9aceb259aaf22 /lib/dynamic_printk.c
parent095160aee954688a9bad225952c4bee546541e19 (diff)
dynamic debug: combine dprintk and dynamic printk
This patch combines Greg Bank's dprintk() work with the existing dynamic printk patchset, we are now calling it 'dynamic debug'. The new feature of this patchset is a richer /debugfs control file interface, (an example output from my system is at the bottom), which allows fined grained control over the the debug output. The output can be controlled by function, file, module, format string, and line number. for example, enabled all debug messages in module 'nf_conntrack': echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control to disable them: echo -n 'module nf_conntrack -p' > /mnt/debugfs/dynamic_debug/control A further explanation can be found in the documentation patch. Signed-off-by: Greg Banks <gnb@sgi.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'lib/dynamic_printk.c')
-rw-r--r--lib/dynamic_printk.c414
1 files changed, 0 insertions, 414 deletions
diff --git a/lib/dynamic_printk.c b/lib/dynamic_printk.c
deleted file mode 100644
index 165a19763dc9..000000000000
--- a/lib/dynamic_printk.c
+++ /dev/null
@@ -1,414 +0,0 @@
1/*
2 * lib/dynamic_printk.c
3 *
4 * make pr_debug()/dev_dbg() calls runtime configurable based upon their
5 * their source module.
6 *
7 * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/uaccess.h>
13#include <linux/seq_file.h>
14#include <linux/debugfs.h>
15#include <linux/fs.h>
16
17extern struct mod_debug __start___verbose[];
18extern struct mod_debug __stop___verbose[];
19
20struct debug_name {
21 struct hlist_node hlist;
22 struct hlist_node hlist2;
23 int hash1;
24 int hash2;
25 char *name;
26 int enable;
27 int type;
28};
29
30static int nr_entries;
31static int num_enabled;
32int dynamic_enabled = DYNAMIC_ENABLED_NONE;
33static struct hlist_head module_table[DEBUG_HASH_TABLE_SIZE] =
34 { [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
35static struct hlist_head module_table2[DEBUG_HASH_TABLE_SIZE] =
36 { [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
37static DECLARE_MUTEX(debug_list_mutex);
38
39/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
40 * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
41 * use independent hash functions, to reduce the chance of false positives.
42 */
43long long dynamic_printk_enabled;
44EXPORT_SYMBOL_GPL(dynamic_printk_enabled);
45long long dynamic_printk_enabled2;
46EXPORT_SYMBOL_GPL(dynamic_printk_enabled2);
47
48/* returns the debug module pointer. */
49static struct debug_name *find_debug_module(char *module_name)
50{
51 int i;
52 struct hlist_head *head;
53 struct hlist_node *node;
54 struct debug_name *element;
55
56 element = NULL;
57 for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
58 head = &module_table[i];
59 hlist_for_each_entry_rcu(element, node, head, hlist)
60 if (!strcmp(element->name, module_name))
61 return element;
62 }
63 return NULL;
64}
65
66/* returns the debug module pointer. */
67static struct debug_name *find_debug_module_hash(char *module_name, int hash)
68{
69 struct hlist_head *head;
70 struct hlist_node *node;
71 struct debug_name *element;
72
73 element = NULL;
74 head = &module_table[hash];
75 hlist_for_each_entry_rcu(element, node, head, hlist)
76 if (!strcmp(element->name, module_name))
77 return element;
78 return NULL;
79}
80
81/* caller must hold mutex*/
82static int __add_debug_module(char *mod_name, int hash, int hash2)
83{
84 struct debug_name *new;
85 char *module_name;
86 int ret = 0;
87
88 if (find_debug_module(mod_name)) {
89 ret = -EINVAL;
90 goto out;
91 }
92 module_name = kmalloc(strlen(mod_name) + 1, GFP_KERNEL);
93 if (!module_name) {
94 ret = -ENOMEM;
95 goto out;
96 }
97 module_name = strcpy(module_name, mod_name);
98 module_name[strlen(mod_name)] = '\0';
99 new = kzalloc(sizeof(struct debug_name), GFP_KERNEL);
100 if (!new) {
101 kfree(module_name);
102 ret = -ENOMEM;
103 goto out;
104 }
105 INIT_HLIST_NODE(&new->hlist);
106 INIT_HLIST_NODE(&new->hlist2);
107 new->name = module_name;
108 new->hash1 = hash;
109 new->hash2 = hash2;
110 hlist_add_head_rcu(&new->hlist, &module_table[hash]);
111 hlist_add_head_rcu(&new->hlist2, &module_table2[hash2]);
112 nr_entries++;
113out:
114 return ret;
115}
116
117int unregister_dynamic_debug_module(char *mod_name)
118{
119 struct debug_name *element;
120 int ret = 0;
121
122 down(&debug_list_mutex);
123 element = find_debug_module(mod_name);
124 if (!element) {
125 ret = -EINVAL;
126 goto out;
127 }
128 hlist_del_rcu(&element->hlist);
129 hlist_del_rcu(&element->hlist2);
130 synchronize_rcu();
131 kfree(element->name);
132 if (element->enable)
133 num_enabled--;
134 kfree(element);
135 nr_entries--;
136out:
137 up(&debug_list_mutex);
138 return ret;
139}
140EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
141
142int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
143 char *flags, int hash, int hash2)
144{
145 struct debug_name *elem;
146 int ret = 0;
147
148 down(&debug_list_mutex);
149 elem = find_debug_module(mod_name);
150 if (!elem) {
151 if (__add_debug_module(mod_name, hash, hash2))
152 goto out;
153 elem = find_debug_module(mod_name);
154 if (dynamic_enabled == DYNAMIC_ENABLED_ALL &&
155 !strcmp(mod_name, share_name)) {
156 elem->enable = true;
157 num_enabled++;
158 }
159 }
160 elem->type |= type;
161out:
162 up(&debug_list_mutex);
163 return ret;
164}
165EXPORT_SYMBOL_GPL(register_dynamic_debug_module);
166
167int __dynamic_dbg_enabled_helper(char *mod_name, int type, int value, int hash)
168{
169 struct debug_name *elem;
170 int ret = 0;
171
172 if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
173 return 1;
174 rcu_read_lock();
175 elem = find_debug_module_hash(mod_name, hash);
176 if (elem && elem->enable)
177 ret = 1;
178 rcu_read_unlock();
179 return ret;
180}
181EXPORT_SYMBOL_GPL(__dynamic_dbg_enabled_helper);
182
183static void set_all(bool enable)
184{
185 struct debug_name *e;
186 struct hlist_node *node;
187 int i;
188 long long enable_mask;
189
190 for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
191 if (module_table[i].first != NULL) {
192 hlist_for_each_entry(e, node, &module_table[i], hlist) {
193 e->enable = enable;
194 }
195 }
196 }
197 if (enable)
198 enable_mask = ULLONG_MAX;
199 else
200 enable_mask = 0;
201 dynamic_printk_enabled = enable_mask;
202 dynamic_printk_enabled2 = enable_mask;
203}
204
205static int disabled_hash(int i, bool first_table)
206{
207 struct debug_name *e;
208 struct hlist_node *node;
209
210 if (first_table) {
211 hlist_for_each_entry(e, node, &module_table[i], hlist) {
212 if (e->enable)
213 return 0;
214 }
215 } else {
216 hlist_for_each_entry(e, node, &module_table2[i], hlist2) {
217 if (e->enable)
218 return 0;
219 }
220 }
221 return 1;
222}
223
224static ssize_t pr_debug_write(struct file *file, const char __user *buf,
225 size_t length, loff_t *ppos)
226{
227 char *buffer, *s, *value_str, *setting_str;
228 int err, value;
229 struct debug_name *elem = NULL;
230 int all = 0;
231
232 if (length > PAGE_SIZE || length < 0)
233 return -EINVAL;
234
235 buffer = (char *)__get_free_page(GFP_KERNEL);
236 if (!buffer)
237 return -ENOMEM;
238
239 err = -EFAULT;
240 if (copy_from_user(buffer, buf, length))
241 goto out;
242
243 err = -EINVAL;
244 if (length < PAGE_SIZE)
245 buffer[length] = '\0';
246 else if (buffer[PAGE_SIZE-1])
247 goto out;
248
249 err = -EINVAL;
250 down(&debug_list_mutex);
251
252 if (strncmp("set", buffer, 3))
253 goto out_up;
254 s = buffer + 3;
255 setting_str = strsep(&s, "=");
256 if (s == NULL)
257 goto out_up;
258 setting_str = strstrip(setting_str);
259 value_str = strsep(&s, " ");
260 if (s == NULL)
261 goto out_up;
262 s = strstrip(s);
263 if (!strncmp(s, "all", 3))
264 all = 1;
265 else
266 elem = find_debug_module(s);
267 if (!strncmp(setting_str, "enable", 6)) {
268 value = !!simple_strtol(value_str, NULL, 10);
269 if (all) {
270 if (value) {
271 set_all(true);
272 num_enabled = nr_entries;
273 dynamic_enabled = DYNAMIC_ENABLED_ALL;
274 } else {
275 set_all(false);
276 num_enabled = 0;
277 dynamic_enabled = DYNAMIC_ENABLED_NONE;
278 }
279 err = 0;
280 } else if (elem) {
281 if (value && (elem->enable == 0)) {
282 dynamic_printk_enabled |= (1LL << elem->hash1);
283 dynamic_printk_enabled2 |= (1LL << elem->hash2);
284 elem->enable = 1;
285 num_enabled++;
286 dynamic_enabled = DYNAMIC_ENABLED_SOME;
287 err = 0;
288 printk(KERN_DEBUG
289 "debugging enabled for module %s\n",
290 elem->name);
291 } else if (!value && (elem->enable == 1)) {
292 elem->enable = 0;
293 num_enabled--;
294 if (disabled_hash(elem->hash1, true))
295 dynamic_printk_enabled &=
296 ~(1LL << elem->hash1);
297 if (disabled_hash(elem->hash2, false))
298 dynamic_printk_enabled2 &=
299 ~(1LL << elem->hash2);
300 if (num_enabled)
301 dynamic_enabled = DYNAMIC_ENABLED_SOME;
302 else
303 dynamic_enabled = DYNAMIC_ENABLED_NONE;
304 err = 0;
305 printk(KERN_DEBUG
306 "debugging disabled for module %s\n",
307 elem->name);
308 }
309 }
310 }
311 if (!err)
312 err = length;
313out_up:
314 up(&debug_list_mutex);
315out:
316 free_page((unsigned long)buffer);
317 return err;
318}
319
320static void *pr_debug_seq_start(struct seq_file *f, loff_t *pos)
321{
322 return (*pos < DEBUG_HASH_TABLE_SIZE) ? pos : NULL;
323}
324
325static void *pr_debug_seq_next(struct seq_file *s, void *v, loff_t *pos)
326{
327 (*pos)++;
328 if (*pos >= DEBUG_HASH_TABLE_SIZE)
329 return NULL;
330 return pos;
331}
332
333static void pr_debug_seq_stop(struct seq_file *s, void *v)
334{
335 /* Nothing to do */
336}
337
338static int pr_debug_seq_show(struct seq_file *s, void *v)
339{
340 struct hlist_head *head;
341 struct hlist_node *node;
342 struct debug_name *elem;
343 unsigned int i = *(loff_t *) v;
344
345 rcu_read_lock();
346 head = &module_table[i];
347 hlist_for_each_entry_rcu(elem, node, head, hlist) {
348 seq_printf(s, "%s enabled=%d", elem->name, elem->enable);
349 seq_printf(s, "\n");
350 }
351 rcu_read_unlock();
352 return 0;
353}
354
355static struct seq_operations pr_debug_seq_ops = {
356 .start = pr_debug_seq_start,
357 .next = pr_debug_seq_next,
358 .stop = pr_debug_seq_stop,
359 .show = pr_debug_seq_show
360};
361
362static int pr_debug_open(struct inode *inode, struct file *filp)
363{
364 return seq_open(filp, &pr_debug_seq_ops);
365}
366
367static const struct file_operations pr_debug_operations = {
368 .open = pr_debug_open,
369 .read = seq_read,
370 .write = pr_debug_write,
371 .llseek = seq_lseek,
372 .release = seq_release,
373};
374
375static int __init dynamic_printk_init(void)
376{
377 struct dentry *dir, *file;
378 struct mod_debug *iter;
379 unsigned long value;
380
381 dir = debugfs_create_dir("dynamic_printk", NULL);
382 if (!dir)
383 return -ENOMEM;
384 file = debugfs_create_file("modules", 0644, dir, NULL,
385 &pr_debug_operations);
386 if (!file) {
387 debugfs_remove(dir);
388 return -ENOMEM;
389 }
390 for (value = (unsigned long)__start___verbose;
391 value < (unsigned long)__stop___verbose;
392 value += sizeof(struct mod_debug)) {
393 iter = (struct mod_debug *)value;
394 register_dynamic_debug_module(iter->modname,
395 iter->type,
396 iter->logical_modname,
397 iter->flag_names, iter->hash, iter->hash2);
398 }
399 if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
400 set_all(true);
401 return 0;
402}
403module_init(dynamic_printk_init);
404/* may want to move this earlier so we can get traces as early as possible */
405
406static int __init dynamic_printk_setup(char *str)
407{
408 if (str)
409 return -ENOENT;
410 dynamic_enabled = DYNAMIC_ENABLED_ALL;
411 return 0;
412}
413/* Use early_param(), so we can get debug output as early as possible */
414early_param("dynamic_printk", dynamic_printk_setup);
generated by cgit v1.2.2 (git 2.25.0) at 2024-10-07 09:32:43 -0400