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1 | /* |
2 | * (C) Copyright 2009-2011 - | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
5 | * LTTng function tracer integration module. | |
6 | * | |
7 | * Dual LGPL v2.1/GPL v2 license. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/ftrace.h> | |
12 | #include <linux/slab.h> | |
13 | #include "../ltt-events.h" | |
14 | #include "../wrapper/ringbuffer/frontend_types.h" | |
15 | #include "../ltt-tracer.h" | |
16 | ||
17 | static | |
18 | int lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data) | |
19 | { | |
20 | struct ltt_event *event = *data; | |
21 | struct ltt_channel *chan = event->chan; | |
22 | struct lib_ring_buffer_ctx ctx; | |
23 | struct { | |
24 | unsigned long ip; | |
25 | unsigned long parent_ip; | |
26 | } payload; | |
27 | int ret; | |
28 | ||
29 | if (!ACCESS_ONCE(chan->session->active)) | |
30 | return 0; | |
31 | lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, | |
32 | sizeof(payload), ltt_alignof(payload), -1); | |
33 | ret = chan->ops->event_reserve(&ctx); | |
34 | if (ret < 0) | |
35 | return 0; | |
36 | payload.ip = ip; | |
37 | payload.parent_ip = parent_ip; | |
38 | lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload)); | |
39 | chan->ops->event_write(&ctx, &payload, sizeof(payload)); | |
40 | chan->ops->event_commit(&ctx); | |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* | |
45 | * Create event description | |
46 | */ | |
47 | static | |
48 | int lttng_create_ftrace_event(const char *name, struct ltt_event *event) | |
49 | { | |
50 | struct lttng_event_field *fields; | |
51 | struct lttng_event_desc *desc; | |
52 | int ret; | |
53 | ||
54 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); | |
55 | if (!desc) | |
56 | return -ENOMEM; | |
57 | desc->name = kstrdup(name, GFP_KERNEL); | |
58 | if (!desc->name) { | |
59 | ret = -ENOMEM; | |
60 | goto error_str; | |
61 | } | |
62 | desc->nr_fields = 2; | |
63 | desc->fields = fields = | |
64 | kzalloc(2 * sizeof(struct lttng_event_field), GFP_KERNEL); | |
65 | fields[0].name = "ip"; | |
66 | fields[0].type.atype = atype_integer; | |
67 | fields[0].type.u.basic.integer.size = sizeof(unsigned long); | |
68 | fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
69 | fields[0].type.u.basic.integer.signedness = 0; | |
70 | fields[0].type.u.basic.integer.reverse_byte_order = 0; | |
71 | fields[0].type.u.basic.integer.base = 16; | |
72 | fields[0].type.u.basic.integer.encoding = lttng_encode_none; | |
73 | ||
74 | fields[1].name = "parent_ip"; | |
75 | fields[1].type.atype = atype_integer; | |
76 | fields[1].type.u.basic.integer.size = sizeof(unsigned long); | |
77 | fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
78 | fields[1].type.u.basic.integer.signedness = 0; | |
79 | fields[1].type.u.basic.integer.reverse_byte_order = 0; | |
80 | fields[1].type.u.basic.integer.base = 16; | |
81 | fields[1].type.u.basic.integer.encoding = lttng_encode_none; | |
82 | ||
83 | event->desc = desc; | |
84 | ||
85 | return 0; | |
86 | ||
87 | error_str: | |
88 | kfree(desc); | |
89 | return ret; | |
90 | } | |
91 | ||
92 | static | |
93 | struct ftrace_probe_ops lttng_ftrace_ops = { | |
94 | .func = lttng_ftrace_handler, | |
95 | }; | |
96 | ||
97 | int lttng_ftrace_register(const char *name, | |
98 | const char *symbol_name, | |
99 | struct ltt_event *event) | |
100 | { | |
101 | int ret; | |
102 | ||
103 | ret = lttng_create_ftrace_event(name, event); | |
104 | if (ret) | |
105 | goto error; | |
106 | ||
107 | event->u.ftrace.symbol_name = kstrdup(name, GFP_KERNEL); | |
108 | if (!event->u.ftrace.symbol_name) | |
109 | goto name_error; | |
110 | ||
111 | ret = register_ftrace_function_probe(symbol_name, | |
112 | <tng_ftrace_ops, event); | |
113 | if (ret) | |
114 | goto register_error; | |
115 | return 0; | |
116 | ||
117 | register_error: | |
118 | kfree(event->u.ftrace.symbol_name); | |
119 | name_error: | |
120 | kfree(event->desc->name); | |
121 | kfree(event->desc); | |
122 | error: | |
123 | return ret; | |
124 | } | |
125 | EXPORT_SYMBOL_GPL(lttng_ftrace_register); | |
126 | ||
127 | void lttng_ftrace_unregister(struct ltt_event *event) | |
128 | { | |
129 | unregister_ftrace_function_probe(event->u.ftrace.symbol_name, | |
130 | <tng_ftrace_ops, event); | |
131 | kfree(event->u.ftrace.symbol_name); | |
132 | kfree(event->desc->name); | |
133 | kfree(event->desc); | |
134 | } | |
135 | EXPORT_SYMBOL_GPL(lttng_ftrace_unregister); | |
136 | ||
137 | MODULE_LICENSE("GPL and additional rights"); | |
138 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
139 | MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support"); |