1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * nop tracer 2 * nop tracer
4 * 3 *
5 * Copyright (C) 2008 Steven Noonan <steven@up 4 * Copyright (C) 2008 Steven Noonan <steven@uplinklabs.net>
6 * 5 *
7 */ 6 */
8 7
9 #include <linux/module.h> 8 #include <linux/module.h>
>> 9 #include <linux/fs.h>
>> 10 #include <linux/debugfs.h>
10 #include <linux/ftrace.h> 11 #include <linux/ftrace.h>
11 12
12 #include "trace.h" 13 #include "trace.h"
13 14
14 /* Our two options */ 15 /* Our two options */
15 enum { 16 enum {
16 TRACE_NOP_OPT_ACCEPT = 0x1, 17 TRACE_NOP_OPT_ACCEPT = 0x1,
17 TRACE_NOP_OPT_REFUSE = 0x2 18 TRACE_NOP_OPT_REFUSE = 0x2
18 }; 19 };
19 20
20 /* Options for the tracer (see trace_options f 21 /* Options for the tracer (see trace_options file) */
21 static struct tracer_opt nop_opts[] = { 22 static struct tracer_opt nop_opts[] = {
22 /* Option that will be accepted by set 23 /* Option that will be accepted by set_flag callback */
23 { TRACER_OPT(test_nop_accept, TRACE_NO 24 { TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) },
24 /* Option that will be refused by set_ 25 /* Option that will be refused by set_flag callback */
25 { TRACER_OPT(test_nop_refuse, TRACE_NO 26 { TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) },
26 { } /* Always set a last empty entry * 27 { } /* Always set a last empty entry */
27 }; 28 };
28 29
29 static struct tracer_flags nop_flags = { 30 static struct tracer_flags nop_flags = {
30 /* You can check your flags value here 31 /* You can check your flags value here when you want. */
31 .val = 0, /* By default: all flags dis 32 .val = 0, /* By default: all flags disabled */
32 .opts = nop_opts 33 .opts = nop_opts
33 }; 34 };
34 35
35 static struct trace_array *ctx_trace; 36 static struct trace_array *ctx_trace;
36 37
37 static void start_nop_trace(struct trace_array 38 static void start_nop_trace(struct trace_array *tr)
38 { 39 {
39 /* Nothing to do! */ 40 /* Nothing to do! */
40 } 41 }
41 42
42 static void stop_nop_trace(struct trace_array 43 static void stop_nop_trace(struct trace_array *tr)
43 { 44 {
44 /* Nothing to do! */ 45 /* Nothing to do! */
45 } 46 }
46 47
47 static int nop_trace_init(struct trace_array * 48 static int nop_trace_init(struct trace_array *tr)
48 { 49 {
49 ctx_trace = tr; 50 ctx_trace = tr;
50 start_nop_trace(tr); 51 start_nop_trace(tr);
51 return 0; 52 return 0;
52 } 53 }
53 54
54 static void nop_trace_reset(struct trace_array 55 static void nop_trace_reset(struct trace_array *tr)
55 { 56 {
56 stop_nop_trace(tr); 57 stop_nop_trace(tr);
57 } 58 }
58 59
59 /* It only serves as a signal handler and a ca 60 /* It only serves as a signal handler and a callback to
60 * accept or refuse the setting of a flag. !! 61 * accept or refuse tthe setting of a flag.
61 * If you don't implement it, then the flag se 62 * If you don't implement it, then the flag setting will be
62 * automatically accepted. 63 * automatically accepted.
63 */ 64 */
64 static int nop_set_flag(struct trace_array *tr !! 65 static int nop_set_flag(u32 old_flags, u32 bit, int set)
65 { 66 {
66 /* 67 /*
67 * Note that you don't need to update 68 * Note that you don't need to update nop_flags.val yourself.
68 * The tracing Api will do it automati 69 * The tracing Api will do it automatically if you return 0
69 */ 70 */
70 if (bit == TRACE_NOP_OPT_ACCEPT) { 71 if (bit == TRACE_NOP_OPT_ACCEPT) {
71 printk(KERN_DEBUG "nop_test_ac 72 printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept."
72 " Now cat trace_option 73 " Now cat trace_options to see the result\n",
73 set); 74 set);
74 return 0; 75 return 0;
75 } 76 }
76 77
77 if (bit == TRACE_NOP_OPT_REFUSE) { 78 if (bit == TRACE_NOP_OPT_REFUSE) {
78 printk(KERN_DEBUG "nop_test_re 79 printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse."
79 " Now cat trace_option !! 80 "Now cat trace_options to see the result\n",
80 set); 81 set);
81 return -EINVAL; 82 return -EINVAL;
82 } 83 }
83 84
84 return 0; 85 return 0;
85 } 86 }
86 87
87 88
88 struct tracer nop_trace __read_mostly = 89 struct tracer nop_trace __read_mostly =
89 { 90 {
90 .name = "nop", 91 .name = "nop",
91 .init = nop_trace_init, 92 .init = nop_trace_init,
92 .reset = nop_trace_reset, 93 .reset = nop_trace_reset,
>> 94 .wait_pipe = poll_wait_pipe,
93 #ifdef CONFIG_FTRACE_SELFTEST 95 #ifdef CONFIG_FTRACE_SELFTEST
94 .selftest = trace_selftest_start 96 .selftest = trace_selftest_startup_nop,
95 #endif 97 #endif
96 .flags = &nop_flags, 98 .flags = &nop_flags,
97 .set_flag = nop_set_flag, !! 99 .set_flag = nop_set_flag
98 .allow_instances = true, <<
99 }; 100 };
100 101
101 102
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.