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-rw-r--r--kernel/trace/trace_nop.c65
1 files changed, 53 insertions, 12 deletions
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index 4592b4862515..b9767acd30ac 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -12,6 +12,27 @@
12 12
13#include "trace.h" 13#include "trace.h"
14 14
15/* Our two options */
16enum {
17 TRACE_NOP_OPT_ACCEPT = 0x1,
18 TRACE_NOP_OPT_REFUSE = 0x2
19};
20
21/* Options for the tracer (see trace_options file) */
22static struct tracer_opt nop_opts[] = {
23 /* Option that will be accepted by set_flag callback */
24 { TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) },
25 /* Option that will be refused by set_flag callback */
26 { TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) },
27 { } /* Always set a last empty entry */
28};
29
30static struct tracer_flags nop_flags = {
31 /* You can check your flags value here when you want. */
32 .val = 0, /* By default: all flags disabled */
33 .opts = nop_opts
34};
35
15static struct trace_array *ctx_trace; 36static struct trace_array *ctx_trace;
16 37
17static void start_nop_trace(struct trace_array *tr) 38static void start_nop_trace(struct trace_array *tr)
@@ -24,7 +45,7 @@ static void stop_nop_trace(struct trace_array *tr)
24 /* Nothing to do! */ 45 /* Nothing to do! */
25} 46}
26 47
27static void nop_trace_init(struct trace_array *tr) 48static int nop_trace_init(struct trace_array *tr)
28{ 49{
29 int cpu; 50 int cpu;
30 ctx_trace = tr; 51 ctx_trace = tr;
@@ -32,33 +53,53 @@ static void nop_trace_init(struct trace_array *tr)
32 for_each_online_cpu(cpu) 53 for_each_online_cpu(cpu)
33 tracing_reset(tr, cpu); 54 tracing_reset(tr, cpu);
34 55
35 if (tr->ctrl) 56 start_nop_trace(tr);
36 start_nop_trace(tr); 57 return 0;
37} 58}
38 59
39static void nop_trace_reset(struct trace_array *tr) 60static void nop_trace_reset(struct trace_array *tr)
40{ 61{
41 if (tr->ctrl) 62 stop_nop_trace(tr);
42 stop_nop_trace(tr);
43} 63}
44 64
45static void nop_trace_ctrl_update(struct trace_array *tr) 65/* It only serves as a signal handler and a callback to
66 * accept or refuse tthe setting of a flag.
67 * If you don't implement it, then the flag setting will be
68 * automatically accepted.
69 */
70static int nop_set_flag(u32 old_flags, u32 bit, int set)
46{ 71{
47 /* When starting a new trace, reset the buffers */ 72 /*
48 if (tr->ctrl) 73 * Note that you don't need to update nop_flags.val yourself.
49 start_nop_trace(tr); 74 * The tracing Api will do it automatically if you return 0
50 else 75 */
51 stop_nop_trace(tr); 76 if (bit == TRACE_NOP_OPT_ACCEPT) {
77 printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept."
78 " Now cat trace_options to see the result\n",
79 set);
80 return 0;
81 }
82
83 if (bit == TRACE_NOP_OPT_REFUSE) {
84 printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse."
85 "Now cat trace_options to see the result\n",
86 set);
87 return -EINVAL;
88 }
89
90 return 0;
52} 91}
53 92
93
54struct tracer nop_trace __read_mostly = 94struct tracer nop_trace __read_mostly =
55{ 95{
56 .name = "nop", 96 .name = "nop",
57 .init = nop_trace_init, 97 .init = nop_trace_init,
58 .reset = nop_trace_reset, 98 .reset = nop_trace_reset,
59 .ctrl_update = nop_trace_ctrl_update,
60#ifdef CONFIG_FTRACE_SELFTEST 99#ifdef CONFIG_FTRACE_SELFTEST
61 .selftest = trace_selftest_startup_nop, 100 .selftest = trace_selftest_startup_nop,
62#endif 101#endif
102 .flags = &nop_flags,
103 .set_flag = nop_set_flag
63}; 104};
64 105