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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; | |
47 | int ret; | |
48 | ||
49 | event->desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); | |
50 | if (!event->desc) | |
51 | return -ENOMEM; | |
52 | event->desc->name = kstrdup(name, GFP_KERNEL); | |
53 | if (!event->desc->name) { | |
54 | ret = -ENOMEM; | |
55 | goto error_str; | |
56 | } | |
57 | event->desc->nr_fields = 1; | |
58 | event->desc->fields = field = | |
59 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); | |
60 | field->name = "ip"; | |
61 | field->type.atype = atype_integer; | |
62 | field->type.u.basic.integer.size = sizeof(unsigned long); | |
63 | field->type.u.basic.integer.alignment = ltt_alignof(unsigned long); | |
64 | field->type.u.basic.integer.signedness = 0; | |
65 | field->type.u.basic.integer.reverse_byte_order = 0; | |
66 | ||
67 | return 0; | |
68 | ||
69 | error_str: | |
70 | kfree(event->desc); | |
71 | return ret; | |
72 | } | |
73 | ||
74 | int lttng_kprobes_register(const char *name, | |
75 | const char *symbol_name, | |
76 | uint64_t offset, | |
77 | uint64_t addr, | |
78 | struct ltt_event *event) | |
79 | { | |
80 | int ret; | |
81 | ||
82 | ret = lttng_create_kprobe_event(name, event); | |
83 | if (ret) | |
84 | goto error; | |
85 | memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp)); | |
86 | event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre; | |
87 | event->u.kprobe.symbol_name = | |
88 | kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char), | |
89 | GFP_KERNEL); | |
90 | if (!event->u.kprobe.symbol_name) { | |
91 | ret = -ENOMEM; | |
92 | goto name_error; | |
93 | } | |
94 | memcpy(event->u.kprobe.symbol_name, symbol_name, | |
95 | LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char)); | |
96 | event->u.kprobe.kp.symbol_name = | |
97 | event->u.kprobe.symbol_name; | |
98 | event->u.kprobe.kp.offset = offset; | |
99 | event->u.kprobe.kp.addr = (void *) addr; | |
100 | ret = register_kprobe(&event->u.kprobe.kp); | |
101 | if (ret) | |
102 | goto register_error; | |
103 | return 0; | |
104 | ||
105 | register_error: | |
106 | kfree(event->u.kprobe.symbol_name); | |
107 | name_error: | |
108 | kfree(event->desc->name); | |
109 | kfree(event->desc); | |
110 | error: | |
111 | return ret; | |
112 | } | |
113 | EXPORT_SYMBOL_GPL(lttng_kprobes_register); | |
114 | ||
115 | void lttng_kprobes_unregister(struct ltt_event *event) | |
116 | { | |
117 | unregister_kprobe(&event->u.kprobe.kp); | |
118 | kfree(event->u.kprobe.symbol_name); | |
119 | kfree(event->desc->name); | |
120 | kfree(event->desc); | |
121 | } | |
122 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister); | |
d6d808f3 MD |
123 | |
124 | MODULE_LICENSE("GPL and additional rights"); | |
125 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
126 | MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support"); |