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> |
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 | }; |
a90917c3 | 29 | struct lttng_channel *chan = event->chan; |
d6d808f3 MD |
30 | struct lib_ring_buffer_ctx ctx; |
31 | int ret; | |
32 | unsigned long data = (unsigned long) p->addr; | |
33 | ||
585e5dcc | 34 | if (unlikely(!LTTNG_READ_ONCE(chan->session->active))) |
f17701fb | 35 | return 0; |
585e5dcc | 36 | if (unlikely(!LTTNG_READ_ONCE(chan->enabled))) |
e64957da | 37 | return 0; |
585e5dcc | 38 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
e64957da MD |
39 | return 0; |
40 | ||
79150a49 | 41 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data), |
a90917c3 | 42 | lttng_alignof(data), -1); |
4e1f08f4 | 43 | ret = chan->ops->event_reserve(&ctx, event->id); |
d6d808f3 | 44 | if (ret < 0) |
f17701fb | 45 | return 0; |
a90917c3 | 46 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); |
d6d808f3 MD |
47 | chan->ops->event_write(&ctx, &data, sizeof(data)); |
48 | chan->ops->event_commit(&ctx); | |
f17701fb | 49 | return 0; |
d6d808f3 | 50 | } |
f17701fb | 51 | |
2b16f0c9 FD |
52 | static |
53 | int lttng_kprobes_event_notifier_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
54 | { | |
55 | struct lttng_event_notifier *event_notifier = | |
56 | container_of(p, struct lttng_event_notifier, u.kprobe.kp); | |
c3eddb2e | 57 | struct lttng_kernel_notifier_ctx notif_ctx; |
2b16f0c9 FD |
58 | |
59 | if (unlikely(!READ_ONCE(event_notifier->enabled))) | |
60 | return 0; | |
61 | ||
c3eddb2e MD |
62 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); |
63 | event_notifier->send_notification(event_notifier, NULL, NULL, ¬if_ctx); | |
2b16f0c9 FD |
64 | |
65 | return 0; | |
66 | } | |
67 | ||
437d5aa5 MD |
68 | static const struct lttng_kernel_type_common *event_type = |
69 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16); | |
70 | ||
f17701fb MD |
71 | /* |
72 | * Create event description | |
73 | */ | |
74 | static | |
a90917c3 | 75 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb | 76 | { |
437d5aa5 MD |
77 | const struct lttng_kernel_event_field **fieldp_array; |
78 | struct lttng_kernel_event_field *field; | |
79 | struct lttng_kernel_event_desc *desc; | |
f17701fb MD |
80 | int ret; |
81 | ||
437d5aa5 | 82 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
d3dbe23c | 83 | if (!desc) |
f17701fb | 84 | return -ENOMEM; |
437d5aa5 MD |
85 | desc->event_name = kstrdup(name, GFP_KERNEL); |
86 | if (!desc->event_name) { | |
f17701fb MD |
87 | ret = -ENOMEM; |
88 | goto error_str; | |
89 | } | |
d3dbe23c | 90 | desc->nr_fields = 1; |
437d5aa5 MD |
91 | fieldp_array = kzalloc(1 * sizeof(struct lttng_kernel_event_field *), GFP_KERNEL); |
92 | if (!fieldp_array) { | |
93 | ret = -ENOMEM; | |
94 | goto error_fieldp_array; | |
95 | } | |
96 | desc->fields = fieldp_array; | |
97 | desc->fields[0] = field = | |
98 | kzalloc(sizeof(struct lttng_kernel_event_field), GFP_KERNEL); | |
0d1a681e MD |
99 | if (!field) { |
100 | ret = -ENOMEM; | |
101 | goto error_field; | |
102 | } | |
f17701fb | 103 | field->name = "ip"; |
437d5aa5 | 104 | field->type = event_type; |
dc7f600a | 105 | desc->owner = THIS_MODULE; |
d3dbe23c | 106 | event->desc = desc; |
f17701fb MD |
107 | |
108 | return 0; | |
109 | ||
0d1a681e | 110 | error_field: |
437d5aa5 MD |
111 | kfree(fieldp_array); |
112 | error_fieldp_array: | |
113 | kfree(desc->event_name); | |
f17701fb | 114 | error_str: |
d3dbe23c | 115 | kfree(desc); |
f17701fb MD |
116 | return ret; |
117 | } | |
118 | ||
2b16f0c9 FD |
119 | /* |
120 | * Create event_notifier description | |
121 | */ | |
122 | static | |
123 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
124 | { | |
437d5aa5 | 125 | struct lttng_kernel_event_desc *desc; |
2b16f0c9 FD |
126 | int ret; |
127 | ||
437d5aa5 | 128 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
2b16f0c9 FD |
129 | if (!desc) |
130 | return -ENOMEM; | |
437d5aa5 MD |
131 | desc->event_name = kstrdup(name, GFP_KERNEL); |
132 | if (!desc->event_name) { | |
2b16f0c9 FD |
133 | ret = -ENOMEM; |
134 | goto error_str; | |
135 | } | |
136 | desc->nr_fields = 0; | |
137 | ||
138 | desc->owner = THIS_MODULE; | |
139 | event_notifier->desc = desc; | |
140 | ||
141 | return 0; | |
142 | ||
143 | error_str: | |
144 | kfree(desc); | |
145 | return ret; | |
146 | } | |
147 | ||
8bf17deb FD |
148 | static |
149 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
150 | uint64_t offset, |
151 | uint64_t addr, | |
8bf17deb FD |
152 | struct lttng_kprobe *lttng_kp, |
153 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
154 | { |
155 | int ret; | |
156 | ||
c37f2a9b MD |
157 | /* Kprobes expects a NULL symbol name if unused */ |
158 | if (symbol_name[0] == '\0') | |
159 | symbol_name = NULL; | |
160 | ||
8bf17deb FD |
161 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
162 | lttng_kp->kp.pre_handler = pre_handler; | |
163 | ||
c37f2a9b | 164 | if (symbol_name) { |
8bf17deb | 165 | lttng_kp->symbol_name = |
606828e4 | 166 | kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 167 | GFP_KERNEL); |
8bf17deb | 168 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
169 | ret = -ENOMEM; |
170 | goto name_error; | |
171 | } | |
8bf17deb | 172 | memcpy(lttng_kp->symbol_name, symbol_name, |
606828e4 | 173 | LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 174 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 175 | } |
8bf17deb FD |
176 | |
177 | lttng_kp->kp.offset = offset; | |
178 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
179 | |
180 | /* | |
196bfc6a | 181 | * Ensure the memory we just allocated don't notify page faults. |
16a9a591 MD |
182 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
183 | * but we can never be too careful. | |
184 | */ | |
263b6c88 | 185 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 186 | |
8bf17deb | 187 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
188 | if (ret) |
189 | goto register_error; | |
8bf17deb | 190 | |
f17701fb MD |
191 | return 0; |
192 | ||
193 | register_error: | |
8bf17deb | 194 | kfree(lttng_kp->symbol_name); |
f17701fb | 195 | name_error: |
8bf17deb FD |
196 | return ret; |
197 | } | |
198 | ||
199 | int lttng_kprobes_register_event(const char *name, | |
200 | const char *symbol_name, | |
201 | uint64_t offset, | |
202 | uint64_t addr, | |
203 | struct lttng_event *event) | |
204 | { | |
205 | int ret; | |
206 | ||
207 | ret = lttng_create_kprobe_event(name, event); | |
208 | if (ret) | |
209 | goto error; | |
210 | ||
211 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
212 | &event->u.kprobe, lttng_kprobes_event_handler_pre); | |
213 | if (ret) | |
214 | goto register_error; | |
215 | ||
216 | return 0; | |
217 | ||
218 | register_error: | |
0d1a681e | 219 | kfree(event->desc->fields); |
437d5aa5 | 220 | kfree(event->desc->event_name); |
f17701fb MD |
221 | kfree(event->desc); |
222 | error: | |
223 | return ret; | |
224 | } | |
8bf17deb | 225 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 226 | |
2b16f0c9 FD |
227 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
228 | uint64_t offset, | |
229 | uint64_t addr, | |
230 | struct lttng_event_notifier *event_notifier) | |
231 | { | |
232 | int ret; | |
233 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
234 | if (ret) | |
235 | goto error; | |
236 | ||
237 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
238 | &event_notifier->u.kprobe, lttng_kprobes_event_notifier_handler_pre); | |
239 | if (ret) | |
240 | goto register_error; | |
241 | ||
242 | return 0; | |
243 | ||
244 | register_error: | |
437d5aa5 | 245 | kfree(event_notifier->desc->event_name); |
2b16f0c9 FD |
246 | kfree(event_notifier->desc); |
247 | error: | |
248 | return ret; | |
249 | } | |
250 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
251 | ||
8bf17deb | 252 | void lttng_kprobes_unregister_event(struct lttng_event *event) |
f17701fb MD |
253 | { |
254 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 | 255 | } |
8bf17deb | 256 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 257 | |
2b16f0c9 FD |
258 | void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
259 | { | |
260 | unregister_kprobe(&event_notifier->u.kprobe.kp); | |
261 | } | |
262 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
263 | ||
8bf17deb | 264 | void lttng_kprobes_destroy_event_private(struct lttng_event *event) |
edeb3137 | 265 | { |
f17701fb | 266 | kfree(event->u.kprobe.symbol_name); |
437d5aa5 | 267 | kfree(event->desc->fields[0]); |
0d1a681e | 268 | kfree(event->desc->fields); |
437d5aa5 | 269 | kfree(event->desc->event_name); |
f17701fb MD |
270 | kfree(event->desc); |
271 | } | |
8bf17deb | 272 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 273 | |
2b16f0c9 FD |
274 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
275 | { | |
276 | kfree(event_notifier->u.kprobe.symbol_name); | |
437d5aa5 | 277 | kfree(event_notifier->desc->event_name); |
2b16f0c9 FD |
278 | kfree(event_notifier->desc); |
279 | } | |
280 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private); | |
281 | ||
d6d808f3 | 282 | MODULE_LICENSE("GPL and additional rights"); |
1c124020 MJ |
283 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
284 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
285 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
286 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
287 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
288 | LTTNG_MODULES_EXTRAVERSION); |