Commit | Line | Data |
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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 | 53 | |
07d777fe SR |
54 | /* allocate the trace_printk per cpu buffers */ |
55 | if (start != end) | |
56 | trace_printk_init_buffers(); | |
57 | ||
769b0441 | 58 | mutex_lock(&btrace_mutex); |
1ba28e02 LJ |
59 | for (iter = start; iter < end; iter++) { |
60 | struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter); | |
61 | if (tb_fmt) { | |
62 | *iter = tb_fmt->fmt; | |
63 | continue; | |
64 | } | |
65 | ||
3a301d7c | 66 | fmt = NULL; |
0588fa30 | 67 | tb_fmt = kmalloc(sizeof(*tb_fmt), GFP_KERNEL); |
3a301d7c | 68 | if (tb_fmt) { |
0588fa30 | 69 | fmt = kmalloc(strlen(*iter) + 1, GFP_KERNEL); |
3a301d7c SR |
70 | if (fmt) { |
71 | list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list); | |
72 | strcpy(fmt, *iter); | |
73 | tb_fmt->fmt = fmt; | |
74 | } else | |
75 | kfree(tb_fmt); | |
0588fa30 | 76 | } |
3a301d7c SR |
77 | *iter = fmt; |
78 | ||
1ba28e02 | 79 | } |
769b0441 | 80 | mutex_unlock(&btrace_mutex); |
1427cdf0 LJ |
81 | } |
82 | ||
1ba28e02 LJ |
83 | static int module_trace_bprintk_format_notify(struct notifier_block *self, |
84 | unsigned long val, void *data) | |
85 | { | |
86 | struct module *mod = data; | |
87 | if (mod->num_trace_bprintk_fmt) { | |
88 | const char **start = mod->trace_bprintk_fmt_start; | |
89 | const char **end = start + mod->num_trace_bprintk_fmt; | |
90 | ||
91 | if (val == MODULE_STATE_COMING) | |
92 | hold_module_trace_bprintk_format(start, end); | |
93 | } | |
94 | return 0; | |
95 | } | |
96 | ||
1813dc37 SR |
97 | /* |
98 | * The debugfs/tracing/printk_formats file maps the addresses with | |
99 | * the ASCII formats that are used in the bprintk events in the | |
100 | * buffer. For userspace tools to be able to decode the events from | |
101 | * the buffer, they need to be able to map the address with the format. | |
102 | * | |
103 | * The addresses of the bprintk formats are in their own section | |
104 | * __trace_printk_fmt. But for modules we copy them into a link list. | |
105 | * The code to print the formats and their addresses passes around the | |
106 | * address of the fmt string. If the fmt address passed into the seq | |
107 | * functions is within the kernel core __trace_printk_fmt section, then | |
108 | * it simply uses the next pointer in the list. | |
109 | * | |
110 | * When the fmt pointer is outside the kernel core __trace_printk_fmt | |
111 | * section, then we need to read the link list pointers. The trick is | |
112 | * we pass the address of the string to the seq function just like | |
113 | * we do for the kernel core formats. To get back the structure that | |
114 | * holds the format, we simply use containerof() and then go to the | |
115 | * next format in the list. | |
116 | */ | |
117 | static const char ** | |
118 | find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) | |
119 | { | |
120 | struct trace_bprintk_fmt *mod_fmt; | |
121 | ||
122 | if (list_empty(&trace_bprintk_fmt_list)) | |
123 | return NULL; | |
124 | ||
125 | /* | |
126 | * v will point to the address of the fmt record from t_next | |
127 | * v will be NULL from t_start. | |
128 | * If this is the first pointer or called from start | |
129 | * then we need to walk the list. | |
130 | */ | |
131 | if (!v || start_index == *pos) { | |
132 | struct trace_bprintk_fmt *p; | |
133 | ||
134 | /* search the module list */ | |
135 | list_for_each_entry(p, &trace_bprintk_fmt_list, list) { | |
136 | if (start_index == *pos) | |
137 | return &p->fmt; | |
138 | start_index++; | |
139 | } | |
140 | /* pos > index */ | |
141 | return NULL; | |
142 | } | |
143 | ||
144 | /* | |
145 | * v points to the address of the fmt field in the mod list | |
146 | * structure that holds the module print format. | |
147 | */ | |
148 | mod_fmt = container_of(v, typeof(*mod_fmt), fmt); | |
149 | if (mod_fmt->list.next == &trace_bprintk_fmt_list) | |
150 | return NULL; | |
151 | ||
152 | mod_fmt = container_of(mod_fmt->list.next, typeof(*mod_fmt), list); | |
153 | ||
154 | return &mod_fmt->fmt; | |
155 | } | |
156 | ||
157 | static void format_mod_start(void) | |
158 | { | |
159 | mutex_lock(&btrace_mutex); | |
160 | } | |
161 | ||
162 | static void format_mod_stop(void) | |
163 | { | |
164 | mutex_unlock(&btrace_mutex); | |
165 | } | |
166 | ||
1ba28e02 LJ |
167 | #else /* !CONFIG_MODULES */ |
168 | __init static int | |
169 | module_trace_bprintk_format_notify(struct notifier_block *self, | |
170 | unsigned long val, void *data) | |
171 | { | |
172 | return 0; | |
173 | } | |
1813dc37 SR |
174 | static inline const char ** |
175 | find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) | |
176 | { | |
177 | return NULL; | |
178 | } | |
179 | static inline void format_mod_start(void) { } | |
180 | static inline void format_mod_stop(void) { } | |
1ba28e02 LJ |
181 | #endif /* CONFIG_MODULES */ |
182 | ||
183 | ||
184 | __initdata_or_module static | |
185 | struct notifier_block module_trace_bprintk_format_nb = { | |
186 | .notifier_call = module_trace_bprintk_format_notify, | |
187 | }; | |
188 | ||
48ead020 | 189 | int __trace_bprintk(unsigned long ip, const char *fmt, ...) |
769b0441 FW |
190 | { |
191 | int ret; | |
192 | va_list ap; | |
1427cdf0 | 193 | |
769b0441 FW |
194 | if (unlikely(!fmt)) |
195 | return 0; | |
1427cdf0 | 196 | |
769b0441 FW |
197 | if (!(trace_flags & TRACE_ITER_PRINTK)) |
198 | return 0; | |
199 | ||
200 | va_start(ap, fmt); | |
40ce74f1 | 201 | ret = trace_vbprintk(ip, fmt, ap); |
769b0441 FW |
202 | va_end(ap); |
203 | return ret; | |
1427cdf0 | 204 | } |
48ead020 | 205 | EXPORT_SYMBOL_GPL(__trace_bprintk); |
1427cdf0 | 206 | |
48ead020 | 207 | int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap) |
769b0441 FW |
208 | { |
209 | if (unlikely(!fmt)) | |
210 | return 0; | |
211 | ||
212 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
213 | return 0; | |
214 | ||
40ce74f1 | 215 | return trace_vbprintk(ip, fmt, ap); |
48ead020 FW |
216 | } |
217 | EXPORT_SYMBOL_GPL(__ftrace_vbprintk); | |
218 | ||
219 | int __trace_printk(unsigned long ip, const char *fmt, ...) | |
220 | { | |
221 | int ret; | |
222 | va_list ap; | |
223 | ||
224 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
225 | return 0; | |
226 | ||
227 | va_start(ap, fmt); | |
40ce74f1 | 228 | ret = trace_vprintk(ip, fmt, ap); |
48ead020 FW |
229 | va_end(ap); |
230 | return ret; | |
231 | } | |
232 | EXPORT_SYMBOL_GPL(__trace_printk); | |
233 | ||
234 | int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) | |
235 | { | |
236 | if (!(trace_flags & TRACE_ITER_PRINTK)) | |
237 | return 0; | |
238 | ||
40ce74f1 | 239 | return trace_vprintk(ip, fmt, ap); |
1427cdf0 | 240 | } |
769b0441 | 241 | EXPORT_SYMBOL_GPL(__ftrace_vprintk); |
1427cdf0 | 242 | |
1813dc37 SR |
243 | static const char **find_next(void *v, loff_t *pos) |
244 | { | |
245 | const char **fmt = v; | |
246 | int start_index; | |
247 | ||
1813dc37 SR |
248 | start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt; |
249 | ||
250 | if (*pos < start_index) | |
db5e7ecc | 251 | return __start___trace_bprintk_fmt + *pos; |
1813dc37 SR |
252 | |
253 | return find_next_mod_format(start_index, v, fmt, pos); | |
254 | } | |
255 | ||
7975a2be | 256 | static void * |
c8961ec6 | 257 | t_start(struct seq_file *m, loff_t *pos) |
7975a2be | 258 | { |
1813dc37 SR |
259 | format_mod_start(); |
260 | return find_next(NULL, pos); | |
7975a2be SR |
261 | } |
262 | ||
c8961ec6 | 263 | static void *t_next(struct seq_file *m, void * v, loff_t *pos) |
7975a2be | 264 | { |
c8961ec6 | 265 | (*pos)++; |
1813dc37 | 266 | return find_next(v, pos); |
7975a2be SR |
267 | } |
268 | ||
269 | static int t_show(struct seq_file *m, void *v) | |
270 | { | |
271 | const char **fmt = v; | |
272 | const char *str = *fmt; | |
273 | int i; | |
274 | ||
4c739ff0 | 275 | seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt); |
7975a2be SR |
276 | |
277 | /* | |
278 | * Tabs and new lines need to be converted. | |
279 | */ | |
280 | for (i = 0; str[i]; i++) { | |
281 | switch (str[i]) { | |
282 | case '\n': | |
283 | seq_puts(m, "\\n"); | |
284 | break; | |
285 | case '\t': | |
286 | seq_puts(m, "\\t"); | |
287 | break; | |
288 | case '\\': | |
289 | seq_puts(m, "\\"); | |
290 | break; | |
291 | case '"': | |
292 | seq_puts(m, "\\\""); | |
293 | break; | |
294 | default: | |
295 | seq_putc(m, str[i]); | |
296 | } | |
297 | } | |
298 | seq_puts(m, "\"\n"); | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | static void t_stop(struct seq_file *m, void *p) | |
304 | { | |
1813dc37 | 305 | format_mod_stop(); |
7975a2be SR |
306 | } |
307 | ||
308 | static const struct seq_operations show_format_seq_ops = { | |
309 | .start = t_start, | |
310 | .next = t_next, | |
311 | .show = t_show, | |
312 | .stop = t_stop, | |
313 | }; | |
314 | ||
315 | static int | |
316 | ftrace_formats_open(struct inode *inode, struct file *file) | |
317 | { | |
c8961ec6 | 318 | return seq_open(file, &show_format_seq_ops); |
7975a2be SR |
319 | } |
320 | ||
321 | static const struct file_operations ftrace_formats_fops = { | |
322 | .open = ftrace_formats_open, | |
323 | .read = seq_read, | |
324 | .llseek = seq_lseek, | |
325 | .release = seq_release, | |
326 | }; | |
327 | ||
328 | static __init int init_trace_printk_function_export(void) | |
329 | { | |
330 | struct dentry *d_tracer; | |
7975a2be SR |
331 | |
332 | d_tracer = tracing_init_dentry(); | |
333 | if (!d_tracer) | |
334 | return 0; | |
335 | ||
5452af66 | 336 | trace_create_file("printk_formats", 0444, d_tracer, |
7975a2be | 337 | NULL, &ftrace_formats_fops); |
7975a2be SR |
338 | |
339 | return 0; | |
340 | } | |
341 | ||
342 | fs_initcall(init_trace_printk_function_export); | |
343 | ||
769b0441 | 344 | static __init int init_trace_printk(void) |
1427cdf0 | 345 | { |
769b0441 | 346 | return register_module_notifier(&module_trace_bprintk_format_nb); |
1427cdf0 LJ |
347 | } |
348 | ||
769b0441 | 349 | early_initcall(init_trace_printk); |