tracing/kprobes: Increment probe hit-count even if it is used by perf
[linux-3.10.git] / kernel / trace / trace_kdb.c
1 /*
2  * kdb helper for dumping the ftrace buffer
3  *
4  * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
5  *
6  * ftrace_dump_buf based on ftrace_dump:
7  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
8  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
9  *
10  */
11 #include <linux/init.h>
12 #include <linux/kgdb.h>
13 #include <linux/kdb.h>
14 #include <linux/ftrace.h>
15
16 #include "trace.h"
17 #include "trace_output.h"
18
19 static void ftrace_dump_buf(int skip_lines, long cpu_file)
20 {
21         /* use static because iter can be a bit big for the stack */
22         static struct trace_iterator iter;
23         unsigned int old_userobj;
24         int cnt = 0, cpu;
25
26         trace_init_global_iter(&iter);
27
28         for_each_tracing_cpu(cpu) {
29                 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
30         }
31
32         old_userobj = trace_flags;
33
34         /* don't look at user memory in panic mode */
35         trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
36
37         kdb_printf("Dumping ftrace buffer:\n");
38
39         /* reset all but tr, trace, and overruns */
40         memset(&iter.seq, 0,
41                    sizeof(struct trace_iterator) -
42                    offsetof(struct trace_iterator, seq));
43         iter.iter_flags |= TRACE_FILE_LAT_FMT;
44         iter.pos = -1;
45
46         if (cpu_file == RING_BUFFER_ALL_CPUS) {
47                 for_each_tracing_cpu(cpu) {
48                         iter.buffer_iter[cpu] =
49                         ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu);
50                         ring_buffer_read_start(iter.buffer_iter[cpu]);
51                         tracing_iter_reset(&iter, cpu);
52                 }
53         } else {
54                 iter.cpu_file = cpu_file;
55                 iter.buffer_iter[cpu_file] =
56                         ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file);
57                 ring_buffer_read_start(iter.buffer_iter[cpu_file]);
58                 tracing_iter_reset(&iter, cpu_file);
59         }
60         if (!trace_empty(&iter))
61                 trace_find_next_entry_inc(&iter);
62         while (!trace_empty(&iter)) {
63                 if (!cnt)
64                         kdb_printf("---------------------------------\n");
65                 cnt++;
66
67                 if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines)
68                         print_trace_line(&iter);
69                 if (!skip_lines)
70                         trace_printk_seq(&iter.seq);
71                 else
72                         skip_lines--;
73                 if (KDB_FLAG(CMD_INTERRUPT))
74                         goto out;
75         }
76
77         if (!cnt)
78                 kdb_printf("   (ftrace buffer empty)\n");
79         else
80                 kdb_printf("---------------------------------\n");
81
82 out:
83         trace_flags = old_userobj;
84
85         for_each_tracing_cpu(cpu) {
86                 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
87         }
88
89         for_each_tracing_cpu(cpu)
90                 if (iter.buffer_iter[cpu])
91                         ring_buffer_read_finish(iter.buffer_iter[cpu]);
92 }
93
94 /*
95  * kdb_ftdump - Dump the ftrace log buffer
96  */
97 static int kdb_ftdump(int argc, const char **argv)
98 {
99         int skip_lines = 0;
100         long cpu_file;
101         char *cp;
102
103         if (argc > 2)
104                 return KDB_ARGCOUNT;
105
106         if (argc) {
107                 skip_lines = simple_strtol(argv[1], &cp, 0);
108                 if (*cp)
109                         skip_lines = 0;
110         }
111
112         if (argc == 2) {
113                 cpu_file = simple_strtol(argv[2], &cp, 0);
114                 if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
115                     !cpu_online(cpu_file))
116                         return KDB_BADINT;
117         } else {
118                 cpu_file = RING_BUFFER_ALL_CPUS;
119         }
120
121         kdb_trap_printk++;
122         ftrace_dump_buf(skip_lines, cpu_file);
123         kdb_trap_printk--;
124
125         return 0;
126 }
127
128 static __init int kdb_ftrace_register(void)
129 {
130         kdb_register_repeat("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
131                             "Dump ftrace log", 0, KDB_REPEAT_NONE);
132         return 0;
133 }
134
135 late_initcall(kdb_ftrace_register);