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> |
2df37e95 | 13 | #include <lttng/events.h> |
a67ba386 | 14 | #include <lttng/events-internal.h> |
24591303 | 15 | #include <ringbuffer/frontend_types.h> |
156a3977 MD |
16 | #include <wrapper/vmalloc.h> |
17 | #include <wrapper/irqflags.h> | |
2df37e95 | 18 | #include <lttng/tracer.h> |
caa068b5 | 19 | #include <blacklist/kprobes.h> |
d6d808f3 | 20 | |
f17701fb | 21 | static |
8bf17deb | 22 | int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs) |
d6d808f3 | 23 | { |
a67ba386 MD |
24 | struct lttng_kernel_event_common_private *event_priv = |
25 | container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp); | |
e2d5dbc7 | 26 | struct lttng_kernel_event_common *event = event_priv->pub; |
a92e844e | 27 | struct lttng_kernel_probe_ctx lttng_probe_ctx = { |
e2d5dbc7 | 28 | .event = event, |
ccecf3fb | 29 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 30 | }; |
d6d808f3 MD |
31 | unsigned long data = (unsigned long) p->addr; |
32 | ||
e2d5dbc7 MD |
33 | switch (event->type) { |
34 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
35 | { | |
36 | struct lttng_kernel_event_recorder_private *event_recorder_priv = | |
37 | container_of(event_priv, struct lttng_kernel_event_recorder_private, parent); | |
38 | struct lttng_kernel_event_recorder *event_recorder = | |
39 | event_recorder_priv->pub; | |
40 | struct lttng_channel *chan = event_recorder->chan; | |
41 | ||
42 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) | |
43 | return 0; | |
44 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) | |
45 | return 0; | |
46 | break; | |
47 | } | |
48 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
49 | break; | |
50 | default: | |
51 | WARN_ON_ONCE(1); | |
52 | } | |
a67ba386 | 53 | |
e2d5dbc7 | 54 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
2b16f0c9 FD |
55 | return 0; |
56 | ||
e2d5dbc7 MD |
57 | switch (event->type) { |
58 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
59 | { | |
60 | struct lttng_kernel_event_recorder *event_recorder = | |
61 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
62 | struct lttng_channel *chan = event_recorder->chan; | |
8a57ec02 | 63 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
64 | int ret; |
65 | ||
b1199bd3 MD |
66 | lib_ring_buffer_ctx_init(&ctx, event_recorder, sizeof(data), |
67 | lttng_alignof(data), <tng_probe_ctx); | |
c2fb9c1c | 68 | ret = chan->ops->event_reserve(&ctx); |
e2d5dbc7 MD |
69 | if (ret < 0) |
70 | return 0; | |
71 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); | |
72 | chan->ops->event_write(&ctx, &data, sizeof(data)); | |
73 | chan->ops->event_commit(&ctx); | |
74 | break; | |
75 | } | |
76 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
77 | { | |
78 | struct lttng_kernel_event_notifier *event_notifier = | |
79 | container_of(event, struct lttng_kernel_event_notifier, parent); | |
80 | struct lttng_kernel_notification_ctx notif_ctx; | |
81 | ||
82 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); | |
83 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); | |
84 | break; | |
85 | } | |
86 | default: | |
87 | WARN_ON_ONCE(1); | |
88 | } | |
2b16f0c9 FD |
89 | return 0; |
90 | } | |
91 | ||
437d5aa5 MD |
92 | static const struct lttng_kernel_type_common *event_type = |
93 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
94 | ||
f17701fb MD |
95 | /* |
96 | * Create event description | |
97 | */ | |
98 | static | |
a67ba386 | 99 | int lttng_create_kprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
f17701fb | 100 | { |
437d5aa5 MD |
101 | const struct lttng_kernel_event_field **fieldp_array; |
102 | struct lttng_kernel_event_field *field; | |
103 | struct lttng_kernel_event_desc *desc; | |
f17701fb MD |
104 | int ret; |
105 | ||
437d5aa5 | 106 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
d3dbe23c | 107 | if (!desc) |
f17701fb | 108 | return -ENOMEM; |
437d5aa5 MD |
109 | desc->event_name = kstrdup(name, GFP_KERNEL); |
110 | if (!desc->event_name) { | |
f17701fb MD |
111 | ret = -ENOMEM; |
112 | goto error_str; | |
113 | } | |
d3dbe23c | 114 | desc->nr_fields = 1; |
437d5aa5 MD |
115 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
116 | if (!fieldp_array) { | |
117 | ret = -ENOMEM; | |
118 | goto error_fieldp_array; | |
119 | } | |
120 | desc->fields = fieldp_array; | |
121 | desc->fields[0] = field = | |
122 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
0d1a681e MD |
123 | if (!field) { |
124 | ret = -ENOMEM; | |
125 | goto error_field; | |
126 | } | |
f17701fb | 127 | field->name = "ip"; |
437d5aa5 | 128 | field->type = event_type; |
dc7f600a | 129 | desc->owner = THIS_MODULE; |
a67ba386 | 130 | event_recorder->priv->parent.desc = desc; |
f17701fb MD |
131 | |
132 | return 0; | |
133 | ||
0d1a681e | 134 | error_field: |
437d5aa5 MD |
135 | kfree(fieldp_array); |
136 | error_fieldp_array: | |
137 | kfree(desc->event_name); | |
f17701fb | 138 | error_str: |
d3dbe23c | 139 | kfree(desc); |
f17701fb MD |
140 | return ret; |
141 | } | |
142 | ||
2b16f0c9 FD |
143 | /* |
144 | * Create event_notifier description | |
145 | */ | |
146 | static | |
a67ba386 | 147 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 148 | { |
437d5aa5 | 149 | struct lttng_kernel_event_desc *desc; |
2b16f0c9 FD |
150 | int ret; |
151 | ||
437d5aa5 | 152 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
2b16f0c9 FD |
153 | if (!desc) |
154 | return -ENOMEM; | |
437d5aa5 MD |
155 | desc->event_name = kstrdup(name, GFP_KERNEL); |
156 | if (!desc->event_name) { | |
2b16f0c9 FD |
157 | ret = -ENOMEM; |
158 | goto error_str; | |
159 | } | |
160 | desc->nr_fields = 0; | |
161 | ||
162 | desc->owner = THIS_MODULE; | |
a67ba386 | 163 | event_notifier->priv->parent.desc = desc; |
2b16f0c9 FD |
164 | |
165 | return 0; | |
166 | ||
167 | error_str: | |
168 | kfree(desc); | |
169 | return ret; | |
170 | } | |
171 | ||
8bf17deb FD |
172 | static |
173 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
174 | uint64_t offset, |
175 | uint64_t addr, | |
8bf17deb FD |
176 | struct lttng_kprobe *lttng_kp, |
177 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
178 | { |
179 | int ret; | |
180 | ||
c37f2a9b MD |
181 | /* Kprobes expects a NULL symbol name if unused */ |
182 | if (symbol_name[0] == '\0') | |
183 | symbol_name = NULL; | |
184 | ||
8bf17deb FD |
185 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
186 | lttng_kp->kp.pre_handler = pre_handler; | |
187 | ||
c37f2a9b | 188 | if (symbol_name) { |
8bf17deb | 189 | lttng_kp->symbol_name = |
606828e4 | 190 | kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 191 | GFP_KERNEL); |
8bf17deb | 192 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
193 | ret = -ENOMEM; |
194 | goto name_error; | |
195 | } | |
8bf17deb | 196 | memcpy(lttng_kp->symbol_name, symbol_name, |
606828e4 | 197 | LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 198 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 199 | } |
8bf17deb FD |
200 | |
201 | lttng_kp->kp.offset = offset; | |
202 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
203 | |
204 | /* | |
196bfc6a | 205 | * Ensure the memory we just allocated don't notify page faults. |
16a9a591 MD |
206 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
207 | * but we can never be too careful. | |
208 | */ | |
263b6c88 | 209 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 210 | |
8bf17deb | 211 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
212 | if (ret) |
213 | goto register_error; | |
8bf17deb | 214 | |
f17701fb MD |
215 | return 0; |
216 | ||
217 | register_error: | |
8bf17deb | 218 | kfree(lttng_kp->symbol_name); |
f17701fb | 219 | name_error: |
8bf17deb FD |
220 | return ret; |
221 | } | |
222 | ||
223 | int lttng_kprobes_register_event(const char *name, | |
224 | const char *symbol_name, | |
225 | uint64_t offset, | |
226 | uint64_t addr, | |
a67ba386 | 227 | struct lttng_kernel_event_recorder *event_recorder) |
8bf17deb FD |
228 | { |
229 | int ret; | |
230 | ||
a67ba386 | 231 | ret = lttng_create_kprobe_event(name, event_recorder); |
8bf17deb FD |
232 | if (ret) |
233 | goto error; | |
234 | ||
235 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
a67ba386 | 236 | &event_recorder->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre); |
8bf17deb FD |
237 | if (ret) |
238 | goto register_error; | |
239 | ||
240 | return 0; | |
241 | ||
242 | register_error: | |
a67ba386 MD |
243 | kfree(event_recorder->priv->parent.desc->fields); |
244 | kfree(event_recorder->priv->parent.desc->event_name); | |
245 | kfree(event_recorder->priv->parent.desc); | |
f17701fb MD |
246 | error: |
247 | return ret; | |
248 | } | |
8bf17deb | 249 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 250 | |
2b16f0c9 FD |
251 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
252 | uint64_t offset, | |
253 | uint64_t addr, | |
a67ba386 | 254 | struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 FD |
255 | { |
256 | int ret; | |
257 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
258 | if (ret) | |
259 | goto error; | |
260 | ||
261 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
e2d5dbc7 | 262 | &event_notifier->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre); |
2b16f0c9 FD |
263 | if (ret) |
264 | goto register_error; | |
265 | ||
266 | return 0; | |
267 | ||
268 | register_error: | |
a67ba386 MD |
269 | kfree(event_notifier->priv->parent.desc->event_name); |
270 | kfree(event_notifier->priv->parent.desc); | |
2b16f0c9 FD |
271 | error: |
272 | return ret; | |
273 | } | |
274 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
275 | ||
a67ba386 | 276 | void lttng_kprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
f17701fb | 277 | { |
a67ba386 | 278 | unregister_kprobe(&event_recorder->priv->parent.u.kprobe.kp); |
edeb3137 | 279 | } |
8bf17deb | 280 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 281 | |
a67ba386 | 282 | void lttng_kprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 283 | { |
a67ba386 | 284 | unregister_kprobe(&event_notifier->priv->parent.u.kprobe.kp); |
2b16f0c9 FD |
285 | } |
286 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
287 | ||
a67ba386 | 288 | void lttng_kprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
edeb3137 | 289 | { |
a67ba386 MD |
290 | kfree(event_recorder->priv->parent.u.kprobe.symbol_name); |
291 | kfree(event_recorder->priv->parent.desc->fields[0]); | |
292 | kfree(event_recorder->priv->parent.desc->fields); | |
293 | kfree(event_recorder->priv->parent.desc->event_name); | |
294 | kfree(event_recorder->priv->parent.desc); | |
f17701fb | 295 | } |
8bf17deb | 296 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 297 | |
a67ba386 | 298 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 299 | { |
a67ba386 MD |
300 | kfree(event_notifier->priv->parent.u.kprobe.symbol_name); |
301 | kfree(event_notifier->priv->parent.desc->event_name); | |
302 | kfree(event_notifier->priv->parent.desc); | |
2b16f0c9 FD |
303 | } |
304 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private); | |
305 | ||
d6d808f3 | 306 | MODULE_LICENSE("GPL and additional rights"); |
1c124020 MJ |
307 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
308 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
309 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
310 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
311 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
312 | LTTNG_MODULES_EXTRAVERSION); |