Commit | Line | Data |
---|---|---|
1427cdf0 LJ |
1 | /* |
2 | * trace binary printk | |
3 | * | |
4 | * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com> | |
5 | * | |
6 | */ | |
7975a2be SR |
7 | #include <linux/seq_file.h> |
8 | #include <linux/debugfs.h> | |
9 | #include <linux/uaccess.h> | |
1427cdf0 LJ |
10 | #include <linux/kernel.h> |
11 | #include <linux/ftrace.h> | |
12 | #include <linux/string.h> | |
7975a2be | 13 | #include <linux/module.h> |
7975a2be | 14 | #include <linux/mutex.h> |
1427cdf0 LJ |
15 | #include <linux/ctype.h> |
16 | #include <linux/list.h> | |
1427cdf0 | 17 | #include <linux/slab.h> |
1427cdf0 | 18 | #include <linux/fs.h> |
1427cdf0 LJ |
19 | |
20 | #include "trace.h" | |
21 | ||
1ba28e02 LJ |
22 | #ifdef CONFIG_MODULES |
23 | ||
1ba28e02 | 24 | /* |
769b0441 | 25 | * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt |
1ba28e02 LJ |
26 | * which are queued on trace_bprintk_fmt_list. |
27 | */ | |
28 | static LIST_HEAD(trace_bprintk_fmt_list); | |
29 | ||
769b0441 FW |
30 | /* serialize accesses to trace_bprintk_fmt_list */ |
31 | static DEFINE_MUTEX(btrace_mutex); | |
32 | ||
1ba28e02 LJ |
33 | struct trace_bprintk_fmt { |
34 | struct list_head list; | |
0588fa30 | 35 | const char *fmt; |
1ba28e02 LJ |
36 | }; |
37 | ||
1ba28e02 | 38 | static inline struct trace_bprintk_fmt *lookup_format(const char *fmt) |
1427cdf0 | 39 | { |
1ba28e02 LJ |
40 | struct trace_bprintk_fmt *pos; |
41 | list_for_each_entry(pos, &trace_bprintk_fmt_list, list) { | |
42 | if (!strcmp(pos->fmt, fmt)) | |
43 | return pos; | |
44 | } | |
45 | return NULL; | |
1427cdf0 LJ |
46 | } |
47 | ||
1ba28e02 LJ |
48 | static |
49 | void hold_module_trace_bprintk_format(const char **start, const char **end) | |
1427cdf0 | 50 | { |
1ba28e02 | 51 | const char **iter; |
0588fa30 | 52 | char *fmt; |
769b0441 FW |
53 | |
54 | mutex_lock(&btrace_mutex); | |
1ba28e02 LJ |
55 | for (iter = start; iter < end; iter++) { |
56 | struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter); | |
57 | if (tb_fmt) { | |
58 | *iter = tb_fmt->fmt; | |
59 | continue; | |
60 | } | |
61 | ||
3a301d7c | 62 | fmt = NULL; |
0588fa30 | 63 | tb_fmt = kmalloc(sizeof(*tb_fmt), GFP_KERNEL); |
3a301d7c | 64 | if (tb_fmt) { |
0588fa30 | 65 | fmt = kmalloc(strlen(*iter) + 1, GFP_KERNEL); |
3a301d7c SR |
66 | if (fmt) { |
67 | list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list); | |
68 | strcpy(fmt, *iter); | |
69 | tb_fmt->fmt = fmt; | |
70 | } else | |
71 | kfree(tb_fmt); | |
0588fa30 | 72 | } |
3a301d7c SR |
73 | *iter = fmt; |
74 | ||
1ba28e02 | 75 | } |
769b0441 | 76 | mutex_unlock(&btrace_mutex); |
1427cdf0 LJ |
77 | } |
78 | ||
1ba28e02 LJ |
79 | static int module_trace_bprintk_format_notify(struct notifier_block *self, |
80 | unsigned long val, void *data) | |
81 | { | |
82 | struct module *mod = data; | |
83 | if (mod->num_trace_bprintk_fmt) { | |
84 | const char **start = mod->trace_bprintk_fmt_start; | |
85 | const char **end = start + mod->num_trace_bprintk_fmt; | |
86 | ||
87 | if (val == MODULE_STATE_COMING) | |
88 | hold_module_trace_bprintk_format(start, end); | |
89 | } | |
90 | return 0; | |
91 | } | |
92 | ||
1813dc37 SR |
93 | /* |
94 | * The debugfs/tracing/printk_formats file maps the addresses with | |
95 | * the ASCII formats that are used in the bprintk events in the | |
96 | * buffer. For userspace tools to be able to decode the events from | |
97 | * the buffer, they need to be able to map the address with the format. | |
98 | * | |
99 | * The addresses of the bprintk formats are in their own section | |
100 | * __trace_printk_fmt. But for modules we copy them into a link list. | |
101 | * The code to print the formats and their addresses passes around the | |
102 | * address of the fmt string. If the fmt address passed into the seq | |
103 | * functions is within the kernel core __trace_printk_fmt section, then | |
104 | * it simply uses the next pointer in the list. | |
105 | * | |
106 | * When the fmt pointer is outside the kernel core __trace_printk_fmt | |
107 | * section, then we need to read the link list pointers. The trick is | |
108 | * we pass the address of the string to the seq function just like | |
109 | * we do for the kernel core formats. To get back the structure that | |
110 | * holds the format, we simply use containerof() and then go to the | |
111 | * next format in the list. | |
112 | */ | |
113 | static const char ** | |
114 | find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) | |
115 | { | |
116 | struct trace_bprintk_fmt *mod_fmt; | |
117 | ||
118 | if (list_empty(&trace_bprintk_fmt_list)) | |
119 | return NULL; | |
120 | ||
121 | /* | |
122 | * v will point to the address of the fmt record from t_next | |
123 | * v will be NULL from t_start. | |
124 | * If this is the first pointer or called from start | |
125 | * then we need to walk the list. | |
126 | */ | |
127 | if (!v || start_index == *pos) { | |
128 | struct trace_bprintk_fmt *p; | |
129 | ||
130 | /* search the module list */ | |
131 | list_for_each_entry(p, &trace_bprintk_fmt_list, list) { | |
132 | if (start_index == *pos) | |
133 | return &p->fmt; | |
134 | start_index++; | |
135 | } | |
136 | /* pos > index */ | |
137 | return NULL; | |
138 | } | |
139 | ||
140 | /* | |
141 | * v points to the address of the fmt field in the mod list | |
142 | * structure that holds the module print format. | |
143 | */ | |
144 | mod_fmt = container_of(v, typeof(*mod_fmt), fmt); | |
145 | if (mod_fmt->list.next == &trace_bprintk_fmt_list) | |
146 | return NULL; | |
147 | ||
148 | mod_fmt = container_of(mod_fmt->list.next, typeof(*mod_fmt), list); | |
149 | ||
150 | return &mod_fmt->fmt; | |
151 | } | |
152 | ||
153 | static void format_mod_start(void) | |
154 | { | |
155 | mutex_lock(&btrace_mutex); | |
156 | } | |
157 | ||
158 | static void format_mod_stop(void) | |
159 | { | |
160 | mutex_unlock(&btrace_mutex); | |
161 | } | |
162 | ||
1ba28e02 LJ |
163 | #else /* !CONFIG_MODULES */ |
164 | __init static int | |
165 | module_trace_bprintk_format_notify(struct notifier_block *self, | |
166 | unsigned long val, void *data) | |
167 | { | |
168 | return 0; | |
169 | } | |
1813dc37 SR |
170 | static inline const char ** |
171 | find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) | |
172 | { | |
173 | return NULL; | |
174 | } | |
175 | static inline void format_mod_start(void) { } | |
176 | static inline void format_mod_stop(void) { } | |
1ba28e02 LJ |
177 | #endif /* CONFIG_MODULES */ |
178 | ||
179 | ||
180 | __initdata_or_module static | |
181 | struct notifier_block module_trace_bprintk_format_nb = { | |
182 | .notifier_call = module_trace_bprintk_format_notify, | |
183 | }; | |
184 | ||
48ead020 | 185 | int __trace_bprintk(unsigned long ip, const char *fmt, ...) |
769b0441 FW |
186 | { |
187 | int ret; | |
188 | va_list ap; | |
1427cdf0 | 189 | |
769b0441 FW |
190 | if (unlikely(!fmt)) |
191 | return 0; | |
1427cdf0 | 192 | |
769b0441 FW |
193 | if (!(trace_flags & TRACE_ITER_PRINTK)) |
194 | return 0; | |
195 | ||
196 | va_start(ap, fmt); | |
40ce74f1 | 197 | ret = trace_vbprintk(ip, fmt, ap); |
769b0441 FW |
198 | va_end(ap); |
199 | return ret; | |
1427cdf0 | 200 | } |
48ead020 | 201 | EXPORT_SYMBOL_GPL(__trace_bprintk); |
1427cdf0 | 202 | |
48ead020 | 203 | int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap) |
769b0441 FW |
204 | { |
205 | if (unlikely(!fmt)) | |
206 | return 0; | |
207 | ||
208 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
209 | return 0; | |
210 | ||
40ce74f1 | 211 | return trace_vbprintk(ip, fmt, ap); |
48ead020 FW |
212 | } |
213 | EXPORT_SYMBOL_GPL(__ftrace_vbprintk); | |
214 | ||
215 | int __trace_printk(unsigned long ip, const char *fmt, ...) | |
216 | { | |
217 | int ret; | |
218 | va_list ap; | |
219 | ||
220 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
221 | return 0; | |
222 | ||
223 | va_start(ap, fmt); | |
40ce74f1 | 224 | ret = trace_vprintk(ip, fmt, ap); |
48ead020 FW |
225 | va_end(ap); |
226 | return ret; | |
227 | } | |
228 | EXPORT_SYMBOL_GPL(__trace_printk); | |
229 | ||
230 | int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) | |
231 | { | |
232 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
233 | return 0; | |
234 | ||
40ce74f1 | 235 | return trace_vprintk(ip, fmt, ap); |
1427cdf0 | 236 | } |
769b0441 | 237 | EXPORT_SYMBOL_GPL(__ftrace_vprintk); |
1427cdf0 | 238 | |
1813dc37 SR |
239 | static const char **find_next(void *v, loff_t *pos) |
240 | { | |
241 | const char **fmt = v; | |
242 | int start_index; | |
243 | ||
1813dc37 SR |
244 | start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt; |
245 | ||
246 | if (*pos < start_index) | |
db5e7ecc | 247 | return __start___trace_bprintk_fmt + *pos; |
1813dc37 SR |
248 | |
249 | return find_next_mod_format(start_index, v, fmt, pos); | |
250 | } | |
251 | ||
7975a2be | 252 | static void * |
c8961ec6 | 253 | t_start(struct seq_file *m, loff_t *pos) |
7975a2be | 254 | { |
1813dc37 SR |
255 | format_mod_start(); |
256 | return find_next(NULL, pos); | |
7975a2be SR |
257 | } |
258 | ||
c8961ec6 | 259 | static void *t_next(struct seq_file *m, void * v, loff_t *pos) |
7975a2be | 260 | { |
c8961ec6 | 261 | (*pos)++; |
1813dc37 | 262 | return find_next(v, pos); |
7975a2be SR |
263 | } |
264 | ||
265 | static int t_show(struct seq_file *m, void *v) | |
266 | { | |
267 | const char **fmt = v; | |
268 | const char *str = *fmt; | |
269 | int i; | |
270 | ||
4c739ff0 | 271 | seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt); |
7975a2be SR |
272 | |
273 | /* | |
274 | * Tabs and new lines need to be converted. | |
275 | */ | |
276 | for (i = 0; str[i]; i++) { | |
277 | switch (str[i]) { | |
278 | case '\n': | |
279 | seq_puts(m, "\\n"); | |
280 | break; | |
281 | case '\t': | |
282 | seq_puts(m, "\\t"); | |
283 | break; | |
284 | case '\\': | |
285 | seq_puts(m, "\\"); | |
286 | break; | |
287 | case '"': | |
288 | seq_puts(m, "\\\""); | |
289 | break; | |
290 | default: | |
291 | seq_putc(m, str[i]); | |
292 | } | |
293 | } | |
294 | seq_puts(m, "\"\n"); | |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | static void t_stop(struct seq_file *m, void *p) | |
300 | { | |
1813dc37 | 301 | format_mod_stop(); |
7975a2be SR |
302 | } |
303 | ||
304 | static const struct seq_operations show_format_seq_ops = { | |
305 | .start = t_start, | |
306 | .next = t_next, | |
307 | .show = t_show, | |
308 | .stop = t_stop, | |
309 | }; | |
310 | ||
311 | static int | |
312 | ftrace_formats_open(struct inode *inode, struct file *file) | |
313 | { | |
c8961ec6 | 314 | return seq_open(file, &show_format_seq_ops); |
7975a2be SR |
315 | } |
316 | ||
317 | static const struct file_operations ftrace_formats_fops = { | |
318 | .open = ftrace_formats_open, | |
319 | .read = seq_read, | |
320 | .llseek = seq_lseek, | |
321 | .release = seq_release, | |
322 | }; | |
323 | ||
324 | static __init int init_trace_printk_function_export(void) | |
325 | { | |
326 | struct dentry *d_tracer; | |
7975a2be SR |
327 | |
328 | d_tracer = tracing_init_dentry(); | |
329 | if (!d_tracer) | |
330 | return 0; | |
331 | ||
5452af66 | 332 | trace_create_file("printk_formats", 0444, d_tracer, |
7975a2be | 333 | NULL, &ftrace_formats_fops); |
7975a2be SR |
334 | |
335 | return 0; | |
336 | } | |
337 | ||
338 | fs_initcall(init_trace_printk_function_export); | |
339 | ||
769b0441 | 340 | static __init int init_trace_printk(void) |
1427cdf0 | 341 | { |
769b0441 | 342 | return register_module_notifier(&module_trace_bprintk_format_nb); |
1427cdf0 LJ |
343 | } |
344 | ||
769b0441 | 345 | early_initcall(init_trace_printk); |