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