Commit | Line | Data |
---|---|---|
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> |
2df37e95 | 13 | #include <lttng/events.h> |
24591303 | 14 | #include <ringbuffer/frontend_types.h> |
156a3977 MD |
15 | #include <wrapper/vmalloc.h> |
16 | #include <wrapper/irqflags.h> | |
2df37e95 | 17 | #include <lttng/tracer.h> |
caa068b5 | 18 | #include <blacklist/kprobes.h> |
d6d808f3 | 19 | |
f17701fb | 20 | static |
8bf17deb | 21 | int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs) |
d6d808f3 | 22 | { |
a90917c3 MD |
23 | struct lttng_event *event = |
24 | container_of(p, struct lttng_event, u.kprobe.kp); | |
79150a49 JD |
25 | struct lttng_probe_ctx lttng_probe_ctx = { |
26 | .event = event, | |
ccecf3fb | 27 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 28 | }; |
710e9669 | 29 | struct lttng_event_container *container = event->container; |
d6d808f3 MD |
30 | int ret; |
31 | unsigned long data = (unsigned long) p->addr; | |
32 | ||
710e9669 | 33 | if (unlikely(!LTTNG_READ_ONCE(container->session->active))) |
f17701fb | 34 | return 0; |
710e9669 | 35 | if (unlikely(!LTTNG_READ_ONCE(container->enabled))) |
e64957da | 36 | return 0; |
585e5dcc | 37 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
e64957da MD |
38 | return 0; |
39 | ||
710e9669 MD |
40 | switch (container->type) { |
41 | case LTTNG_EVENT_CONTAINER_CHANNEL: | |
42 | { | |
43 | struct lttng_channel *chan = lttng_event_container_get_channel(container); | |
44 | struct lib_ring_buffer_ctx ctx; | |
45 | ||
46 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data), | |
47 | lttng_alignof(data), -1); | |
48 | ret = chan->ops->event_reserve(&ctx, event->id); | |
49 | if (ret < 0) | |
50 | return 0; | |
51 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); | |
52 | chan->ops->event_write(&ctx, &data, sizeof(data)); | |
53 | chan->ops->event_commit(&ctx); | |
54 | break; | |
55 | } | |
56 | case LTTNG_EVENT_CONTAINER_COUNTER: | |
57 | { | |
58 | struct lttng_counter *counter = lttng_event_container_get_counter(container); | |
59 | size_t index = event->id; | |
60 | ||
61 | (void) counter->ops->counter_add(counter->counter, &index, 1); | |
62 | break; | |
63 | } | |
64 | } | |
f17701fb | 65 | return 0; |
d6d808f3 | 66 | } |
f17701fb | 67 | |
2b16f0c9 FD |
68 | static |
69 | int lttng_kprobes_event_notifier_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
70 | { | |
71 | struct lttng_event_notifier *event_notifier = | |
72 | container_of(p, struct lttng_event_notifier, u.kprobe.kp); | |
710e9669 | 73 | struct lttng_kernel_notifier_ctx notif_ctx; |
2b16f0c9 FD |
74 | |
75 | if (unlikely(!READ_ONCE(event_notifier->enabled))) | |
76 | return 0; | |
77 | ||
710e9669 MD |
78 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); |
79 | event_notifier->send_notification(event_notifier, NULL, NULL, ¬if_ctx); | |
2b16f0c9 FD |
80 | |
81 | return 0; | |
82 | } | |
83 | ||
f17701fb MD |
84 | /* |
85 | * Create event description | |
86 | */ | |
87 | static | |
a90917c3 | 88 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb MD |
89 | { |
90 | struct lttng_event_field *field; | |
d3dbe23c | 91 | struct lttng_event_desc *desc; |
f17701fb MD |
92 | int ret; |
93 | ||
d3dbe23c MD |
94 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
95 | if (!desc) | |
f17701fb | 96 | return -ENOMEM; |
d3dbe23c MD |
97 | desc->name = kstrdup(name, GFP_KERNEL); |
98 | if (!desc->name) { | |
f17701fb MD |
99 | ret = -ENOMEM; |
100 | goto error_str; | |
101 | } | |
d3dbe23c MD |
102 | desc->nr_fields = 1; |
103 | desc->fields = field = | |
f17701fb | 104 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
0d1a681e MD |
105 | if (!field) { |
106 | ret = -ENOMEM; | |
107 | goto error_field; | |
108 | } | |
f17701fb MD |
109 | field->name = "ip"; |
110 | field->type.atype = atype_integer; | |
ceabb767 MD |
111 | field->type.u.integer.size = sizeof(unsigned long) * CHAR_BIT; |
112 | field->type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; | |
113 | field->type.u.integer.signedness = lttng_is_signed_type(unsigned long); | |
114 | field->type.u.integer.reverse_byte_order = 0; | |
115 | field->type.u.integer.base = 16; | |
116 | field->type.u.integer.encoding = lttng_encode_none; | |
dc7f600a | 117 | desc->owner = THIS_MODULE; |
d3dbe23c | 118 | event->desc = desc; |
f17701fb MD |
119 | |
120 | return 0; | |
121 | ||
0d1a681e MD |
122 | error_field: |
123 | kfree(desc->name); | |
f17701fb | 124 | error_str: |
d3dbe23c | 125 | kfree(desc); |
f17701fb MD |
126 | return ret; |
127 | } | |
128 | ||
2b16f0c9 FD |
129 | /* |
130 | * Create event_notifier description | |
131 | */ | |
132 | static | |
133 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
134 | { | |
135 | struct lttng_event_desc *desc; | |
136 | int ret; | |
137 | ||
138 | desc = kzalloc(sizeof(*event_notifier->desc), GFP_KERNEL); | |
139 | if (!desc) | |
140 | return -ENOMEM; | |
141 | desc->name = kstrdup(name, GFP_KERNEL); | |
142 | if (!desc->name) { | |
143 | ret = -ENOMEM; | |
144 | goto error_str; | |
145 | } | |
146 | desc->nr_fields = 0; | |
147 | ||
148 | desc->owner = THIS_MODULE; | |
149 | event_notifier->desc = desc; | |
150 | ||
151 | return 0; | |
152 | ||
153 | error_str: | |
154 | kfree(desc); | |
155 | return ret; | |
156 | } | |
157 | ||
8bf17deb FD |
158 | static |
159 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
160 | uint64_t offset, |
161 | uint64_t addr, | |
8bf17deb FD |
162 | struct lttng_kprobe *lttng_kp, |
163 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
164 | { |
165 | int ret; | |
166 | ||
c37f2a9b MD |
167 | /* Kprobes expects a NULL symbol name if unused */ |
168 | if (symbol_name[0] == '\0') | |
169 | symbol_name = NULL; | |
170 | ||
8bf17deb FD |
171 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
172 | lttng_kp->kp.pre_handler = pre_handler; | |
173 | ||
c37f2a9b | 174 | if (symbol_name) { |
8bf17deb | 175 | lttng_kp->symbol_name = |
f8695253 | 176 | kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 177 | GFP_KERNEL); |
8bf17deb | 178 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
179 | ret = -ENOMEM; |
180 | goto name_error; | |
181 | } | |
8bf17deb | 182 | memcpy(lttng_kp->symbol_name, symbol_name, |
f8695253 | 183 | LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 184 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 185 | } |
8bf17deb FD |
186 | |
187 | lttng_kp->kp.offset = offset; | |
188 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
189 | |
190 | /* | |
2b16f0c9 | 191 | * Ensure the memory we just allocated don't event_notifier page faults. |
16a9a591 MD |
192 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
193 | * but we can never be too careful. | |
194 | */ | |
263b6c88 | 195 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 196 | |
8bf17deb | 197 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
198 | if (ret) |
199 | goto register_error; | |
8bf17deb | 200 | |
f17701fb MD |
201 | return 0; |
202 | ||
203 | register_error: | |
8bf17deb | 204 | kfree(lttng_kp->symbol_name); |
f17701fb | 205 | name_error: |
8bf17deb FD |
206 | return ret; |
207 | } | |
208 | ||
209 | int lttng_kprobes_register_event(const char *name, | |
210 | const char *symbol_name, | |
211 | uint64_t offset, | |
212 | uint64_t addr, | |
213 | struct lttng_event *event) | |
214 | { | |
215 | int ret; | |
216 | ||
217 | ret = lttng_create_kprobe_event(name, event); | |
218 | if (ret) | |
219 | goto error; | |
220 | ||
221 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
222 | &event->u.kprobe, lttng_kprobes_event_handler_pre); | |
223 | if (ret) | |
224 | goto register_error; | |
225 | ||
226 | return 0; | |
227 | ||
228 | register_error: | |
0d1a681e | 229 | kfree(event->desc->fields); |
f17701fb MD |
230 | kfree(event->desc->name); |
231 | kfree(event->desc); | |
232 | error: | |
233 | return ret; | |
234 | } | |
8bf17deb | 235 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 236 | |
2b16f0c9 FD |
237 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
238 | uint64_t offset, | |
239 | uint64_t addr, | |
240 | struct lttng_event_notifier *event_notifier) | |
241 | { | |
242 | int ret; | |
243 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
244 | if (ret) | |
245 | goto error; | |
246 | ||
247 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
248 | &event_notifier->u.kprobe, lttng_kprobes_event_notifier_handler_pre); | |
249 | if (ret) | |
250 | goto register_error; | |
251 | ||
252 | return 0; | |
253 | ||
254 | register_error: | |
255 | kfree(event_notifier->desc->name); | |
256 | kfree(event_notifier->desc); | |
257 | error: | |
258 | return ret; | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
261 | ||
8bf17deb | 262 | void lttng_kprobes_unregister_event(struct lttng_event *event) |
f17701fb MD |
263 | { |
264 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 | 265 | } |
8bf17deb | 266 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 267 | |
2b16f0c9 FD |
268 | void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
269 | { | |
270 | unregister_kprobe(&event_notifier->u.kprobe.kp); | |
271 | } | |
272 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
273 | ||
8bf17deb | 274 | void lttng_kprobes_destroy_event_private(struct lttng_event *event) |
edeb3137 | 275 | { |
f17701fb | 276 | kfree(event->u.kprobe.symbol_name); |
0d1a681e | 277 | kfree(event->desc->fields); |
f17701fb MD |
278 | kfree(event->desc->name); |
279 | kfree(event->desc); | |
280 | } | |
8bf17deb | 281 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 282 | |
2b16f0c9 FD |
283 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
284 | { | |
285 | kfree(event_notifier->u.kprobe.symbol_name); | |
286 | kfree(event_notifier->desc->name); | |
287 | kfree(event_notifier->desc); | |
288 | } | |
289 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private); | |
290 | ||
d6d808f3 | 291 | MODULE_LICENSE("GPL and additional rights"); |
1c124020 MJ |
292 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
293 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
294 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
295 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
296 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
297 | LTTNG_MODULES_EXTRAVERSION); |