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> |
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); | |
26 | struct lttng_kernel_event_recorder_private *event_recorder_priv = | |
27 | container_of(event_priv, struct lttng_kernel_event_recorder_private, parent); | |
28 | struct lttng_kernel_event_recorder *event_recorder = | |
29 | event_recorder_priv->pub; | |
79150a49 | 30 | struct lttng_probe_ctx lttng_probe_ctx = { |
a67ba386 | 31 | .event = event_recorder, |
ccecf3fb | 32 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 33 | }; |
a67ba386 | 34 | struct lttng_channel *chan = event_recorder->chan; |
d6d808f3 MD |
35 | struct lib_ring_buffer_ctx ctx; |
36 | int ret; | |
37 | unsigned long data = (unsigned long) p->addr; | |
38 | ||
585e5dcc | 39 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) |
f17701fb | 40 | return 0; |
585e5dcc | 41 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) |
e64957da | 42 | return 0; |
a67ba386 | 43 | if (unlikely(!LTTNG_READ_ONCE(event_recorder->parent.enabled))) |
e64957da MD |
44 | return 0; |
45 | ||
79150a49 | 46 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data), |
a90917c3 | 47 | lttng_alignof(data), -1); |
a67ba386 | 48 | ret = chan->ops->event_reserve(&ctx, event_recorder->priv->id); |
d6d808f3 | 49 | if (ret < 0) |
f17701fb | 50 | return 0; |
a90917c3 | 51 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); |
d6d808f3 MD |
52 | chan->ops->event_write(&ctx, &data, sizeof(data)); |
53 | chan->ops->event_commit(&ctx); | |
f17701fb | 54 | return 0; |
d6d808f3 | 55 | } |
f17701fb | 56 | |
2b16f0c9 FD |
57 | static |
58 | int lttng_kprobes_event_notifier_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
59 | { | |
a67ba386 MD |
60 | struct lttng_kernel_event_common_private *event_priv = |
61 | container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp); | |
62 | struct lttng_kernel_event_notifier_private *event_notifier_priv = | |
63 | container_of(event_priv, struct lttng_kernel_event_notifier_private, parent); | |
64 | struct lttng_kernel_event_notifier *event_notifier = | |
65 | event_notifier_priv->pub; | |
66 | struct lttng_kernel_notification_ctx notif_ctx; | |
67 | ||
68 | if (unlikely(!READ_ONCE(event_notifier->parent.enabled))) | |
2b16f0c9 FD |
69 | return 0; |
70 | ||
c3eddb2e | 71 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); |
a67ba386 | 72 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); |
2b16f0c9 FD |
73 | |
74 | return 0; | |
75 | } | |
76 | ||
437d5aa5 MD |
77 | static const struct lttng_kernel_type_common *event_type = |
78 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
79 | ||
f17701fb MD |
80 | /* |
81 | * Create event description | |
82 | */ | |
83 | static | |
a67ba386 | 84 | int lttng_create_kprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder) |
f17701fb | 85 | { |
437d5aa5 MD |
86 | const struct lttng_kernel_event_field **fieldp_array; |
87 | struct lttng_kernel_event_field *field; | |
88 | struct lttng_kernel_event_desc *desc; | |
f17701fb MD |
89 | int ret; |
90 | ||
437d5aa5 | 91 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
d3dbe23c | 92 | if (!desc) |
f17701fb | 93 | return -ENOMEM; |
437d5aa5 MD |
94 | desc->event_name = kstrdup(name, GFP_KERNEL); |
95 | if (!desc->event_name) { | |
f17701fb MD |
96 | ret = -ENOMEM; |
97 | goto error_str; | |
98 | } | |
d3dbe23c | 99 | desc->nr_fields = 1; |
437d5aa5 MD |
100 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
101 | if (!fieldp_array) { | |
102 | ret = -ENOMEM; | |
103 | goto error_fieldp_array; | |
104 | } | |
105 | desc->fields = fieldp_array; | |
106 | desc->fields[0] = field = | |
107 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
0d1a681e MD |
108 | if (!field) { |
109 | ret = -ENOMEM; | |
110 | goto error_field; | |
111 | } | |
f17701fb | 112 | field->name = "ip"; |
437d5aa5 | 113 | field->type = event_type; |
dc7f600a | 114 | desc->owner = THIS_MODULE; |
a67ba386 | 115 | event_recorder->priv->parent.desc = desc; |
f17701fb MD |
116 | |
117 | return 0; | |
118 | ||
0d1a681e | 119 | error_field: |
437d5aa5 MD |
120 | kfree(fieldp_array); |
121 | error_fieldp_array: | |
122 | kfree(desc->event_name); | |
f17701fb | 123 | error_str: |
d3dbe23c | 124 | kfree(desc); |
f17701fb MD |
125 | return ret; |
126 | } | |
127 | ||
2b16f0c9 FD |
128 | /* |
129 | * Create event_notifier description | |
130 | */ | |
131 | static | |
a67ba386 | 132 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 133 | { |
437d5aa5 | 134 | struct lttng_kernel_event_desc *desc; |
2b16f0c9 FD |
135 | int ret; |
136 | ||
437d5aa5 | 137 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
2b16f0c9 FD |
138 | if (!desc) |
139 | return -ENOMEM; | |
437d5aa5 MD |
140 | desc->event_name = kstrdup(name, GFP_KERNEL); |
141 | if (!desc->event_name) { | |
2b16f0c9 FD |
142 | ret = -ENOMEM; |
143 | goto error_str; | |
144 | } | |
145 | desc->nr_fields = 0; | |
146 | ||
147 | desc->owner = THIS_MODULE; | |
a67ba386 | 148 | event_notifier->priv->parent.desc = desc; |
2b16f0c9 FD |
149 | |
150 | return 0; | |
151 | ||
152 | error_str: | |
153 | kfree(desc); | |
154 | return ret; | |
155 | } | |
156 | ||
8bf17deb FD |
157 | static |
158 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
159 | uint64_t offset, |
160 | uint64_t addr, | |
8bf17deb FD |
161 | struct lttng_kprobe *lttng_kp, |
162 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
163 | { |
164 | int ret; | |
165 | ||
c37f2a9b MD |
166 | /* Kprobes expects a NULL symbol name if unused */ |
167 | if (symbol_name[0] == '\0') | |
168 | symbol_name = NULL; | |
169 | ||
8bf17deb FD |
170 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
171 | lttng_kp->kp.pre_handler = pre_handler; | |
172 | ||
c37f2a9b | 173 | if (symbol_name) { |
8bf17deb | 174 | lttng_kp->symbol_name = |
606828e4 | 175 | kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 176 | GFP_KERNEL); |
8bf17deb | 177 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
178 | ret = -ENOMEM; |
179 | goto name_error; | |
180 | } | |
8bf17deb | 181 | memcpy(lttng_kp->symbol_name, symbol_name, |
606828e4 | 182 | LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 183 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 184 | } |
8bf17deb FD |
185 | |
186 | lttng_kp->kp.offset = offset; | |
187 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
188 | |
189 | /* | |
196bfc6a | 190 | * Ensure the memory we just allocated don't notify page faults. |
16a9a591 MD |
191 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
192 | * but we can never be too careful. | |
193 | */ | |
263b6c88 | 194 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 195 | |
8bf17deb | 196 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
197 | if (ret) |
198 | goto register_error; | |
8bf17deb | 199 | |
f17701fb MD |
200 | return 0; |
201 | ||
202 | register_error: | |
8bf17deb | 203 | kfree(lttng_kp->symbol_name); |
f17701fb | 204 | name_error: |
8bf17deb FD |
205 | return ret; |
206 | } | |
207 | ||
208 | int lttng_kprobes_register_event(const char *name, | |
209 | const char *symbol_name, | |
210 | uint64_t offset, | |
211 | uint64_t addr, | |
a67ba386 | 212 | struct lttng_kernel_event_recorder *event_recorder) |
8bf17deb FD |
213 | { |
214 | int ret; | |
215 | ||
a67ba386 | 216 | ret = lttng_create_kprobe_event(name, event_recorder); |
8bf17deb FD |
217 | if (ret) |
218 | goto error; | |
219 | ||
220 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
a67ba386 | 221 | &event_recorder->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre); |
8bf17deb FD |
222 | if (ret) |
223 | goto register_error; | |
224 | ||
225 | return 0; | |
226 | ||
227 | register_error: | |
a67ba386 MD |
228 | kfree(event_recorder->priv->parent.desc->fields); |
229 | kfree(event_recorder->priv->parent.desc->event_name); | |
230 | kfree(event_recorder->priv->parent.desc); | |
f17701fb MD |
231 | error: |
232 | return ret; | |
233 | } | |
8bf17deb | 234 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 235 | |
2b16f0c9 FD |
236 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
237 | uint64_t offset, | |
238 | uint64_t addr, | |
a67ba386 | 239 | struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 FD |
240 | { |
241 | int ret; | |
242 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
243 | if (ret) | |
244 | goto error; | |
245 | ||
246 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
a67ba386 | 247 | &event_notifier->priv->parent.u.kprobe, lttng_kprobes_event_notifier_handler_pre); |
2b16f0c9 FD |
248 | if (ret) |
249 | goto register_error; | |
250 | ||
251 | return 0; | |
252 | ||
253 | register_error: | |
a67ba386 MD |
254 | kfree(event_notifier->priv->parent.desc->event_name); |
255 | kfree(event_notifier->priv->parent.desc); | |
2b16f0c9 FD |
256 | error: |
257 | return ret; | |
258 | } | |
259 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
260 | ||
a67ba386 | 261 | void lttng_kprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder) |
f17701fb | 262 | { |
a67ba386 | 263 | unregister_kprobe(&event_recorder->priv->parent.u.kprobe.kp); |
edeb3137 | 264 | } |
8bf17deb | 265 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 266 | |
a67ba386 | 267 | void lttng_kprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 268 | { |
a67ba386 | 269 | unregister_kprobe(&event_notifier->priv->parent.u.kprobe.kp); |
2b16f0c9 FD |
270 | } |
271 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
272 | ||
a67ba386 | 273 | void lttng_kprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder) |
edeb3137 | 274 | { |
a67ba386 MD |
275 | kfree(event_recorder->priv->parent.u.kprobe.symbol_name); |
276 | kfree(event_recorder->priv->parent.desc->fields[0]); | |
277 | kfree(event_recorder->priv->parent.desc->fields); | |
278 | kfree(event_recorder->priv->parent.desc->event_name); | |
279 | kfree(event_recorder->priv->parent.desc); | |
f17701fb | 280 | } |
8bf17deb | 281 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 282 | |
a67ba386 | 283 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
2b16f0c9 | 284 | { |
a67ba386 MD |
285 | kfree(event_notifier->priv->parent.u.kprobe.symbol_name); |
286 | kfree(event_notifier->priv->parent.desc->event_name); | |
287 | kfree(event_notifier->priv->parent.desc); | |
2b16f0c9 FD |
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); |