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d6d808f3 MD |
1 | /* |
2 | * (C) Copyright 2009-2011 - | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
5 | * LTTng kprobes integration module. | |
6 | * | |
7 | * Dual LGPL v2.1/GPL v2 license. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/kprobes.h> | |
f17701fb | 12 | #include <linux/slab.h> |
d6d808f3 MD |
13 | #include "../ltt-events.h" |
14 | #include "../wrapper/ringbuffer/frontend_types.h" | |
15 | #include "../ltt-tracer.h" | |
16 | ||
f17701fb MD |
17 | static |
18 | int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
d6d808f3 MD |
19 | { |
20 | struct ltt_event *event = | |
21 | container_of(p, struct ltt_event, u.kprobe.kp); | |
22 | struct ltt_channel *chan = event->chan; | |
23 | struct lib_ring_buffer_ctx ctx; | |
24 | int ret; | |
25 | unsigned long data = (unsigned long) p->addr; | |
26 | ||
27 | if (!ACCESS_ONCE(chan->session->active)) | |
f17701fb | 28 | return 0; |
d6d808f3 MD |
29 | lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data), |
30 | ltt_alignof(data), -1); | |
31 | ret = chan->ops->event_reserve(&ctx); | |
32 | if (ret < 0) | |
f17701fb | 33 | return 0; |
d6d808f3 MD |
34 | lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data)); |
35 | chan->ops->event_write(&ctx, &data, sizeof(data)); | |
36 | chan->ops->event_commit(&ctx); | |
f17701fb | 37 | return 0; |
d6d808f3 | 38 | } |
f17701fb MD |
39 | |
40 | /* | |
41 | * Create event description | |
42 | */ | |
43 | static | |
44 | int lttng_create_kprobe_event(const char *name, struct ltt_event *event) | |
45 | { | |
46 | struct lttng_event_field *field; | |
d3dbe23c | 47 | struct lttng_event_desc *desc; |
f17701fb MD |
48 | int ret; |
49 | ||
d3dbe23c MD |
50 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
51 | if (!desc) | |
f17701fb | 52 | return -ENOMEM; |
d3dbe23c MD |
53 | desc->name = kstrdup(name, GFP_KERNEL); |
54 | if (!desc->name) { | |
f17701fb MD |
55 | ret = -ENOMEM; |
56 | goto error_str; | |
57 | } | |
d3dbe23c MD |
58 | desc->nr_fields = 1; |
59 | desc->fields = field = | |
f17701fb MD |
60 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
61 | field->name = "ip"; | |
62 | field->type.atype = atype_integer; | |
63 | field->type.u.basic.integer.size = sizeof(unsigned long); | |
64 | field->type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
65 | field->type.u.basic.integer.signedness = 0; | |
66 | field->type.u.basic.integer.reverse_byte_order = 0; | |
e0a7a7c4 MD |
67 | field->type.u.basic.integer.base = 16; |
68 | field->type.u.basic.integer.encoding = lttng_encode_none; | |
d3dbe23c | 69 | event->desc = desc; |
f17701fb MD |
70 | |
71 | return 0; | |
72 | ||
73 | error_str: | |
d3dbe23c | 74 | kfree(desc); |
f17701fb MD |
75 | return ret; |
76 | } | |
77 | ||
78 | int lttng_kprobes_register(const char *name, | |
79 | const char *symbol_name, | |
80 | uint64_t offset, | |
81 | uint64_t addr, | |
82 | struct ltt_event *event) | |
83 | { | |
84 | int ret; | |
85 | ||
86 | ret = lttng_create_kprobe_event(name, event); | |
87 | if (ret) | |
88 | goto error; | |
89 | memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp)); | |
90 | event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre; | |
91 | event->u.kprobe.symbol_name = | |
e0a7a7c4 | 92 | kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char), |
f17701fb MD |
93 | GFP_KERNEL); |
94 | if (!event->u.kprobe.symbol_name) { | |
95 | ret = -ENOMEM; | |
96 | goto name_error; | |
97 | } | |
98 | memcpy(event->u.kprobe.symbol_name, symbol_name, | |
e0a7a7c4 | 99 | LTTNG_SYM_NAME_LEN * sizeof(char)); |
f17701fb MD |
100 | event->u.kprobe.kp.symbol_name = |
101 | event->u.kprobe.symbol_name; | |
102 | event->u.kprobe.kp.offset = offset; | |
103 | event->u.kprobe.kp.addr = (void *) addr; | |
104 | ret = register_kprobe(&event->u.kprobe.kp); | |
105 | if (ret) | |
106 | goto register_error; | |
107 | return 0; | |
108 | ||
109 | register_error: | |
110 | kfree(event->u.kprobe.symbol_name); | |
111 | name_error: | |
112 | kfree(event->desc->name); | |
113 | kfree(event->desc); | |
114 | error: | |
115 | return ret; | |
116 | } | |
117 | EXPORT_SYMBOL_GPL(lttng_kprobes_register); | |
118 | ||
119 | void lttng_kprobes_unregister(struct ltt_event *event) | |
120 | { | |
121 | unregister_kprobe(&event->u.kprobe.kp); | |
122 | kfree(event->u.kprobe.symbol_name); | |
123 | kfree(event->desc->name); | |
124 | kfree(event->desc); | |
125 | } | |
126 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister); | |
d6d808f3 MD |
127 | |
128 | MODULE_LICENSE("GPL and additional rights"); | |
129 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
130 | MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support"); |