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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; | |
d3dbe23c | 67 | event->desc = desc; |
f17701fb MD |
68 | |
69 | return 0; | |
70 | ||
71 | error_str: | |
d3dbe23c | 72 | kfree(desc); |
f17701fb MD |
73 | return ret; |
74 | } | |
75 | ||
76 | int lttng_kprobes_register(const char *name, | |
77 | const char *symbol_name, | |
78 | uint64_t offset, | |
79 | uint64_t addr, | |
80 | struct ltt_event *event) | |
81 | { | |
82 | int ret; | |
83 | ||
84 | ret = lttng_create_kprobe_event(name, event); | |
85 | if (ret) | |
86 | goto error; | |
87 | memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp)); | |
88 | event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre; | |
89 | event->u.kprobe.symbol_name = | |
90 | kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char), | |
91 | GFP_KERNEL); | |
92 | if (!event->u.kprobe.symbol_name) { | |
93 | ret = -ENOMEM; | |
94 | goto name_error; | |
95 | } | |
96 | memcpy(event->u.kprobe.symbol_name, symbol_name, | |
97 | LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char)); | |
98 | event->u.kprobe.kp.symbol_name = | |
99 | event->u.kprobe.symbol_name; | |
100 | event->u.kprobe.kp.offset = offset; | |
101 | event->u.kprobe.kp.addr = (void *) addr; | |
102 | ret = register_kprobe(&event->u.kprobe.kp); | |
103 | if (ret) | |
104 | goto register_error; | |
105 | return 0; | |
106 | ||
107 | register_error: | |
108 | kfree(event->u.kprobe.symbol_name); | |
109 | name_error: | |
110 | kfree(event->desc->name); | |
111 | kfree(event->desc); | |
112 | error: | |
113 | return ret; | |
114 | } | |
115 | EXPORT_SYMBOL_GPL(lttng_kprobes_register); | |
116 | ||
117 | void lttng_kprobes_unregister(struct ltt_event *event) | |
118 | { | |
119 | unregister_kprobe(&event->u.kprobe.kp); | |
120 | kfree(event->u.kprobe.symbol_name); | |
121 | kfree(event->desc->name); | |
122 | kfree(event->desc); | |
123 | } | |
124 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister); | |
d6d808f3 MD |
125 | |
126 | MODULE_LICENSE("GPL and additional rights"); | |
127 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
128 | MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support"); |