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e0a7a7c4 MD |
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" | |
5a9479dc | 15 | #include "../wrapper/ftrace.h" |
e0a7a7c4 MD |
16 | #include "../ltt-tracer.h" |
17 | ||
18 | static | |
5a9479dc | 19 | void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data) |
e0a7a7c4 MD |
20 | { |
21 | struct ltt_event *event = *data; | |
22 | struct ltt_channel *chan = event->chan; | |
23 | struct lib_ring_buffer_ctx ctx; | |
24 | struct { | |
25 | unsigned long ip; | |
26 | unsigned long parent_ip; | |
27 | } payload; | |
28 | int ret; | |
29 | ||
30 | if (!ACCESS_ONCE(chan->session->active)) | |
5a9479dc | 31 | return; |
e0a7a7c4 MD |
32 | lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, |
33 | sizeof(payload), ltt_alignof(payload), -1); | |
34 | ret = chan->ops->event_reserve(&ctx); | |
35 | if (ret < 0) | |
5a9479dc | 36 | return; |
e0a7a7c4 MD |
37 | payload.ip = ip; |
38 | payload.parent_ip = parent_ip; | |
39 | lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload)); | |
40 | chan->ops->event_write(&ctx, &payload, sizeof(payload)); | |
41 | chan->ops->event_commit(&ctx); | |
5a9479dc | 42 | return; |
e0a7a7c4 MD |
43 | } |
44 | ||
45 | /* | |
46 | * Create event description | |
47 | */ | |
48 | static | |
49 | int lttng_create_ftrace_event(const char *name, struct ltt_event *event) | |
50 | { | |
51 | struct lttng_event_field *fields; | |
52 | struct lttng_event_desc *desc; | |
53 | int ret; | |
54 | ||
55 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); | |
56 | if (!desc) | |
57 | return -ENOMEM; | |
58 | desc->name = kstrdup(name, GFP_KERNEL); | |
59 | if (!desc->name) { | |
60 | ret = -ENOMEM; | |
61 | goto error_str; | |
62 | } | |
63 | desc->nr_fields = 2; | |
64 | desc->fields = fields = | |
65 | kzalloc(2 * sizeof(struct lttng_event_field), GFP_KERNEL); | |
66 | fields[0].name = "ip"; | |
67 | fields[0].type.atype = atype_integer; | |
68 | fields[0].type.u.basic.integer.size = sizeof(unsigned long); | |
69 | fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
70 | fields[0].type.u.basic.integer.signedness = 0; | |
71 | fields[0].type.u.basic.integer.reverse_byte_order = 0; | |
72 | fields[0].type.u.basic.integer.base = 16; | |
73 | fields[0].type.u.basic.integer.encoding = lttng_encode_none; | |
74 | ||
75 | fields[1].name = "parent_ip"; | |
76 | fields[1].type.atype = atype_integer; | |
77 | fields[1].type.u.basic.integer.size = sizeof(unsigned long); | |
78 | fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
79 | fields[1].type.u.basic.integer.signedness = 0; | |
80 | fields[1].type.u.basic.integer.reverse_byte_order = 0; | |
81 | fields[1].type.u.basic.integer.base = 16; | |
82 | fields[1].type.u.basic.integer.encoding = lttng_encode_none; | |
83 | ||
84 | event->desc = desc; | |
85 | ||
86 | return 0; | |
87 | ||
88 | error_str: | |
89 | kfree(desc); | |
90 | return ret; | |
91 | } | |
92 | ||
93 | static | |
94 | struct ftrace_probe_ops lttng_ftrace_ops = { | |
95 | .func = lttng_ftrace_handler, | |
96 | }; | |
97 | ||
98 | int lttng_ftrace_register(const char *name, | |
99 | const char *symbol_name, | |
100 | struct ltt_event *event) | |
101 | { | |
102 | int ret; | |
103 | ||
104 | ret = lttng_create_ftrace_event(name, event); | |
105 | if (ret) | |
106 | goto error; | |
107 | ||
108 | event->u.ftrace.symbol_name = kstrdup(name, GFP_KERNEL); | |
109 | if (!event->u.ftrace.symbol_name) | |
110 | goto name_error; | |
111 | ||
5a9479dc | 112 | ret = wrapper_register_ftrace_function_probe(event->u.ftrace.symbol_name, |
e0a7a7c4 MD |
113 | <tng_ftrace_ops, event); |
114 | if (ret) | |
115 | goto register_error; | |
116 | return 0; | |
117 | ||
118 | register_error: | |
119 | kfree(event->u.ftrace.symbol_name); | |
120 | name_error: | |
121 | kfree(event->desc->name); | |
122 | kfree(event->desc); | |
123 | error: | |
124 | return ret; | |
125 | } | |
126 | EXPORT_SYMBOL_GPL(lttng_ftrace_register); | |
127 | ||
128 | void lttng_ftrace_unregister(struct ltt_event *event) | |
129 | { | |
5a9479dc | 130 | wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name, |
e0a7a7c4 MD |
131 | <tng_ftrace_ops, event); |
132 | kfree(event->u.ftrace.symbol_name); | |
133 | kfree(event->desc->name); | |
134 | kfree(event->desc); | |
135 | } | |
136 | EXPORT_SYMBOL_GPL(lttng_ftrace_unregister); | |
137 | ||
138 | MODULE_LICENSE("GPL and additional rights"); | |
139 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
140 | MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support"); |