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-rw-r--r--kernel/trace/trace_printk.c270
1 files changed, 270 insertions, 0 deletions
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644
index 000000000000..eb81556107fe
--- /dev/null
+++ b/kernel/trace/trace_printk.c
@@ -0,0 +1,270 @@
1/*
2 * trace binary printk
3 *
4 * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
5 *
6 */
7#include <linux/seq_file.h>
8#include <linux/debugfs.h>
9#include <linux/uaccess.h>
10#include <linux/kernel.h>
11#include <linux/ftrace.h>
12#include <linux/string.h>
13#include <linux/module.h>
14#include <linux/marker.h>
15#include <linux/mutex.h>
16#include <linux/ctype.h>
17#include <linux/list.h>
18#include <linux/slab.h>
19#include <linux/fs.h>
20
21#include "trace.h"
22
23#ifdef CONFIG_MODULES
24
25/*
26 * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
27 * which are queued on trace_bprintk_fmt_list.
28 */
29static LIST_HEAD(trace_bprintk_fmt_list);
30
31/* serialize accesses to trace_bprintk_fmt_list */
32static DEFINE_MUTEX(btrace_mutex);
33
34struct trace_bprintk_fmt {
35 struct list_head list;
36 char fmt[0];
37};
38
39static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
40{
41 struct trace_bprintk_fmt *pos;
42 list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
43 if (!strcmp(pos->fmt, fmt))
44 return pos;
45 }
46 return NULL;
47}
48
49static
50void hold_module_trace_bprintk_format(const char **start, const char **end)
51{
52 const char **iter;
53
54 mutex_lock(&btrace_mutex);
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
62 tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt)
63 + strlen(*iter) + 1, GFP_KERNEL);
64 if (tb_fmt) {
65 list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
66 strcpy(tb_fmt->fmt, *iter);
67 *iter = tb_fmt->fmt;
68 } else
69 *iter = NULL;
70 }
71 mutex_unlock(&btrace_mutex);
72}
73
74static int module_trace_bprintk_format_notify(struct notifier_block *self,
75 unsigned long val, void *data)
76{
77 struct module *mod = data;
78 if (mod->num_trace_bprintk_fmt) {
79 const char **start = mod->trace_bprintk_fmt_start;
80 const char **end = start + mod->num_trace_bprintk_fmt;
81
82 if (val == MODULE_STATE_COMING)
83 hold_module_trace_bprintk_format(start, end);
84 }
85 return 0;
86}
87
88#else /* !CONFIG_MODULES */
89__init static int
90module_trace_bprintk_format_notify(struct notifier_block *self,
91 unsigned long val, void *data)
92{
93 return 0;
94}
95#endif /* CONFIG_MODULES */
96
97
98__initdata_or_module static
99struct notifier_block module_trace_bprintk_format_nb = {
100 .notifier_call = module_trace_bprintk_format_notify,
101};
102
103int __trace_bprintk(unsigned long ip, const char *fmt, ...)
104 {
105 int ret;
106 va_list ap;
107
108 if (unlikely(!fmt))
109 return 0;
110
111 if (!(trace_flags & TRACE_ITER_PRINTK))
112 return 0;
113
114 va_start(ap, fmt);
115 ret = trace_vbprintk(ip, fmt, ap);
116 va_end(ap);
117 return ret;
118}
119EXPORT_SYMBOL_GPL(__trace_bprintk);
120
121int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap)
122 {
123 if (unlikely(!fmt))
124 return 0;
125
126 if (!(trace_flags & TRACE_ITER_PRINTK))
127 return 0;
128
129 return trace_vbprintk(ip, fmt, ap);
130}
131EXPORT_SYMBOL_GPL(__ftrace_vbprintk);
132
133int __trace_printk(unsigned long ip, const char *fmt, ...)
134{
135 int ret;
136 va_list ap;
137
138 if (!(trace_flags & TRACE_ITER_PRINTK))
139 return 0;
140
141 va_start(ap, fmt);
142 ret = trace_vprintk(ip, fmt, ap);
143 va_end(ap);
144 return ret;
145}
146EXPORT_SYMBOL_GPL(__trace_printk);
147
148int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
149{
150 if (!(trace_flags & TRACE_ITER_PRINTK))
151 return 0;
152
153 return trace_vprintk(ip, fmt, ap);
154}
155EXPORT_SYMBOL_GPL(__ftrace_vprintk);
156
157static void *
158t_next(struct seq_file *m, void *v, loff_t *pos)
159{
160 const char **fmt = m->private;
161 const char **next = fmt;
162
163 (*pos)++;
164
165 if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt)
166 return NULL;
167
168 next = fmt;
169 m->private = ++next;
170
171 return fmt;
172}
173
174static void *t_start(struct seq_file *m, loff_t *pos)
175{
176 return t_next(m, NULL, pos);
177}
178
179static int t_show(struct seq_file *m, void *v)
180{
181 const char **fmt = v;
182 const char *str = *fmt;
183 int i;
184
185 seq_printf(m, "0x%lx : \"", (unsigned long)fmt);
186
187 /*
188 * Tabs and new lines need to be converted.
189 */
190 for (i = 0; str[i]; i++) {
191 switch (str[i]) {
192 case '\n':
193 seq_puts(m, "\\n");
194 break;
195 case '\t':
196 seq_puts(m, "\\t");
197 break;
198 case '\\':
199 seq_puts(m, "\\");
200 break;
201 case '"':
202 seq_puts(m, "\\\"");
203 break;
204 default:
205 seq_putc(m, str[i]);
206 }
207 }
208 seq_puts(m, "\"\n");
209
210 return 0;
211}
212
213static void t_stop(struct seq_file *m, void *p)
214{
215}
216
217static const struct seq_operations show_format_seq_ops = {
218 .start = t_start,
219 .next = t_next,
220 .show = t_show,
221 .stop = t_stop,
222};
223
224static int
225ftrace_formats_open(struct inode *inode, struct file *file)
226{
227 int ret;
228
229 ret = seq_open(file, &show_format_seq_ops);
230 if (!ret) {
231 struct seq_file *m = file->private_data;
232
233 m->private = __start___trace_bprintk_fmt;
234 }
235 return ret;
236}
237
238static const struct file_operations ftrace_formats_fops = {
239 .open = ftrace_formats_open,
240 .read = seq_read,
241 .llseek = seq_lseek,
242 .release = seq_release,
243};
244
245static __init int init_trace_printk_function_export(void)
246{
247 struct dentry *d_tracer;
248 struct dentry *entry;
249
250 d_tracer = tracing_init_dentry();
251 if (!d_tracer)
252 return 0;
253
254 entry = debugfs_create_file("printk_formats", 0444, d_tracer,
255 NULL, &ftrace_formats_fops);
256 if (!entry)
257 pr_warning("Could not create debugfs "
258 "'printk_formats' entry\n");
259
260 return 0;
261}
262
263fs_initcall(init_trace_printk_function_export);
264
265static __init int init_trace_printk(void)
266{
267 return register_module_notifier(&module_trace_bprintk_format_nb);
268}
269
270early_initcall(init_trace_printk);