Commit | Line | Data |
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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
9f36eaed | 2 | * |
886d51a3 | 3 | * probes/lttng-kprobes.c |
d6d808f3 MD |
4 | * |
5 | * LTTng kprobes integration module. | |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
d6d808f3 MD |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/kprobes.h> | |
f17701fb | 12 | #include <linux/slab.h> |
156a3977 | 13 | #include <lttng-events.h> |
5760f3f4 | 14 | #include <include/ringbuffer/frontend_types.h> |
156a3977 MD |
15 | #include <wrapper/irqflags.h> |
16 | #include <lttng-tracer.h> | |
d6d808f3 | 17 | |
f17701fb MD |
18 | static |
19 | int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
d6d808f3 | 20 | { |
a90917c3 MD |
21 | struct lttng_event *event = |
22 | container_of(p, struct lttng_event, u.kprobe.kp); | |
79150a49 JD |
23 | struct lttng_probe_ctx lttng_probe_ctx = { |
24 | .event = event, | |
ccecf3fb | 25 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 26 | }; |
a90917c3 | 27 | struct lttng_channel *chan = event->chan; |
d6d808f3 MD |
28 | struct lib_ring_buffer_ctx ctx; |
29 | int ret; | |
30 | unsigned long data = (unsigned long) p->addr; | |
31 | ||
a8f2d0c7 | 32 | if (unlikely(!READ_ONCE(chan->session->active))) |
f17701fb | 33 | return 0; |
a8f2d0c7 | 34 | if (unlikely(!READ_ONCE(chan->enabled))) |
e64957da | 35 | return 0; |
a8f2d0c7 | 36 | if (unlikely(!READ_ONCE(event->enabled))) |
e64957da MD |
37 | return 0; |
38 | ||
79150a49 | 39 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data), |
a90917c3 | 40 | lttng_alignof(data), -1); |
4e1f08f4 | 41 | ret = chan->ops->event_reserve(&ctx, event->id); |
d6d808f3 | 42 | if (ret < 0) |
f17701fb | 43 | return 0; |
a90917c3 | 44 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); |
d6d808f3 MD |
45 | chan->ops->event_write(&ctx, &data, sizeof(data)); |
46 | chan->ops->event_commit(&ctx); | |
f17701fb | 47 | return 0; |
d6d808f3 | 48 | } |
f17701fb MD |
49 | |
50 | /* | |
51 | * Create event description | |
52 | */ | |
53 | static | |
a90917c3 | 54 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb MD |
55 | { |
56 | struct lttng_event_field *field; | |
d3dbe23c | 57 | struct lttng_event_desc *desc; |
f17701fb MD |
58 | int ret; |
59 | ||
d3dbe23c MD |
60 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
61 | if (!desc) | |
f17701fb | 62 | return -ENOMEM; |
d3dbe23c MD |
63 | desc->name = kstrdup(name, GFP_KERNEL); |
64 | if (!desc->name) { | |
f17701fb MD |
65 | ret = -ENOMEM; |
66 | goto error_str; | |
67 | } | |
d3dbe23c MD |
68 | desc->nr_fields = 1; |
69 | desc->fields = field = | |
f17701fb | 70 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
0d1a681e MD |
71 | if (!field) { |
72 | ret = -ENOMEM; | |
73 | goto error_field; | |
74 | } | |
f17701fb MD |
75 | field->name = "ip"; |
76 | field->type.atype = atype_integer; | |
ceabb767 MD |
77 | field->type.u.integer.size = sizeof(unsigned long) * CHAR_BIT; |
78 | field->type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; | |
79 | field->type.u.integer.signedness = lttng_is_signed_type(unsigned long); | |
80 | field->type.u.integer.reverse_byte_order = 0; | |
81 | field->type.u.integer.base = 16; | |
82 | field->type.u.integer.encoding = lttng_encode_none; | |
dc7f600a | 83 | desc->owner = THIS_MODULE; |
d3dbe23c | 84 | event->desc = desc; |
f17701fb MD |
85 | |
86 | return 0; | |
87 | ||
0d1a681e MD |
88 | error_field: |
89 | kfree(desc->name); | |
f17701fb | 90 | error_str: |
d3dbe23c | 91 | kfree(desc); |
f17701fb MD |
92 | return ret; |
93 | } | |
94 | ||
95 | int lttng_kprobes_register(const char *name, | |
96 | const char *symbol_name, | |
97 | uint64_t offset, | |
98 | uint64_t addr, | |
a90917c3 | 99 | struct lttng_event *event) |
f17701fb MD |
100 | { |
101 | int ret; | |
102 | ||
c37f2a9b MD |
103 | /* Kprobes expects a NULL symbol name if unused */ |
104 | if (symbol_name[0] == '\0') | |
105 | symbol_name = NULL; | |
106 | ||
f17701fb MD |
107 | ret = lttng_create_kprobe_event(name, event); |
108 | if (ret) | |
109 | goto error; | |
110 | memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp)); | |
111 | event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre; | |
c37f2a9b MD |
112 | if (symbol_name) { |
113 | event->u.kprobe.symbol_name = | |
f8695253 | 114 | kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char), |
c37f2a9b MD |
115 | GFP_KERNEL); |
116 | if (!event->u.kprobe.symbol_name) { | |
117 | ret = -ENOMEM; | |
118 | goto name_error; | |
119 | } | |
120 | memcpy(event->u.kprobe.symbol_name, symbol_name, | |
f8695253 | 121 | LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char)); |
c37f2a9b MD |
122 | event->u.kprobe.kp.symbol_name = |
123 | event->u.kprobe.symbol_name; | |
f17701fb | 124 | } |
f17701fb | 125 | event->u.kprobe.kp.offset = offset; |
b2c4e8fb | 126 | event->u.kprobe.kp.addr = (void *) (unsigned long) addr; |
16a9a591 | 127 | |
f17701fb MD |
128 | ret = register_kprobe(&event->u.kprobe.kp); |
129 | if (ret) | |
130 | goto register_error; | |
131 | return 0; | |
132 | ||
133 | register_error: | |
134 | kfree(event->u.kprobe.symbol_name); | |
135 | name_error: | |
0d1a681e | 136 | kfree(event->desc->fields); |
f17701fb MD |
137 | kfree(event->desc->name); |
138 | kfree(event->desc); | |
139 | error: | |
140 | return ret; | |
141 | } | |
142 | EXPORT_SYMBOL_GPL(lttng_kprobes_register); | |
143 | ||
a90917c3 | 144 | void lttng_kprobes_unregister(struct lttng_event *event) |
f17701fb MD |
145 | { |
146 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 MD |
147 | } |
148 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister); | |
149 | ||
a90917c3 | 150 | void lttng_kprobes_destroy_private(struct lttng_event *event) |
edeb3137 | 151 | { |
f17701fb | 152 | kfree(event->u.kprobe.symbol_name); |
0d1a681e | 153 | kfree(event->desc->fields); |
f17701fb MD |
154 | kfree(event->desc->name); |
155 | kfree(event->desc); | |
156 | } | |
edeb3137 | 157 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private); |
d6d808f3 MD |
158 | |
159 | MODULE_LICENSE("GPL and additional rights"); | |
1c124020 MJ |
160 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
161 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
162 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
163 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
164 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
165 | LTTNG_MODULES_EXTRAVERSION); |