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 | ||
f17701fb MD |
68 | /* |
69 | * Create event description | |
70 | */ | |
71 | static | |
a90917c3 | 72 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb MD |
73 | { |
74 | struct lttng_event_field *field; | |
d3dbe23c | 75 | struct lttng_event_desc *desc; |
f17701fb MD |
76 | int ret; |
77 | ||
d3dbe23c MD |
78 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
79 | if (!desc) | |
f17701fb | 80 | return -ENOMEM; |
d3dbe23c MD |
81 | desc->name = kstrdup(name, GFP_KERNEL); |
82 | if (!desc->name) { | |
f17701fb MD |
83 | ret = -ENOMEM; |
84 | goto error_str; | |
85 | } | |
d3dbe23c MD |
86 | desc->nr_fields = 1; |
87 | desc->fields = field = | |
f17701fb | 88 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
0d1a681e MD |
89 | if (!field) { |
90 | ret = -ENOMEM; | |
91 | goto error_field; | |
92 | } | |
f17701fb | 93 | field->name = "ip"; |
12bb2edb | 94 | field->type.type = lttng_kernel_type_integer; |
ceabb767 MD |
95 | field->type.u.integer.size = sizeof(unsigned long) * CHAR_BIT; |
96 | field->type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; | |
97 | field->type.u.integer.signedness = lttng_is_signed_type(unsigned long); | |
98 | field->type.u.integer.reverse_byte_order = 0; | |
99 | field->type.u.integer.base = 16; | |
100 | field->type.u.integer.encoding = lttng_encode_none; | |
dc7f600a | 101 | desc->owner = THIS_MODULE; |
d3dbe23c | 102 | event->desc = desc; |
f17701fb MD |
103 | |
104 | return 0; | |
105 | ||
0d1a681e MD |
106 | error_field: |
107 | kfree(desc->name); | |
f17701fb | 108 | error_str: |
d3dbe23c | 109 | kfree(desc); |
f17701fb MD |
110 | return ret; |
111 | } | |
112 | ||
2b16f0c9 FD |
113 | /* |
114 | * Create event_notifier description | |
115 | */ | |
116 | static | |
117 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
118 | { | |
119 | struct lttng_event_desc *desc; | |
120 | int ret; | |
121 | ||
122 | desc = kzalloc(sizeof(*event_notifier->desc), GFP_KERNEL); | |
123 | if (!desc) | |
124 | return -ENOMEM; | |
125 | desc->name = kstrdup(name, GFP_KERNEL); | |
126 | if (!desc->name) { | |
127 | ret = -ENOMEM; | |
128 | goto error_str; | |
129 | } | |
130 | desc->nr_fields = 0; | |
131 | ||
132 | desc->owner = THIS_MODULE; | |
133 | event_notifier->desc = desc; | |
134 | ||
135 | return 0; | |
136 | ||
137 | error_str: | |
138 | kfree(desc); | |
139 | return ret; | |
140 | } | |
141 | ||
8bf17deb FD |
142 | static |
143 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
144 | uint64_t offset, |
145 | uint64_t addr, | |
8bf17deb FD |
146 | struct lttng_kprobe *lttng_kp, |
147 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
148 | { |
149 | int ret; | |
150 | ||
c37f2a9b MD |
151 | /* Kprobes expects a NULL symbol name if unused */ |
152 | if (symbol_name[0] == '\0') | |
153 | symbol_name = NULL; | |
154 | ||
8bf17deb FD |
155 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
156 | lttng_kp->kp.pre_handler = pre_handler; | |
157 | ||
c37f2a9b | 158 | if (symbol_name) { |
8bf17deb | 159 | lttng_kp->symbol_name = |
f8695253 | 160 | kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 161 | GFP_KERNEL); |
8bf17deb | 162 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
163 | ret = -ENOMEM; |
164 | goto name_error; | |
165 | } | |
8bf17deb | 166 | memcpy(lttng_kp->symbol_name, symbol_name, |
f8695253 | 167 | LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 168 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 169 | } |
8bf17deb FD |
170 | |
171 | lttng_kp->kp.offset = offset; | |
172 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
173 | |
174 | /* | |
196bfc6a | 175 | * Ensure the memory we just allocated don't notify page faults. |
16a9a591 MD |
176 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
177 | * but we can never be too careful. | |
178 | */ | |
263b6c88 | 179 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 180 | |
8bf17deb | 181 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
182 | if (ret) |
183 | goto register_error; | |
8bf17deb | 184 | |
f17701fb MD |
185 | return 0; |
186 | ||
187 | register_error: | |
8bf17deb | 188 | kfree(lttng_kp->symbol_name); |
f17701fb | 189 | name_error: |
8bf17deb FD |
190 | return ret; |
191 | } | |
192 | ||
193 | int lttng_kprobes_register_event(const char *name, | |
194 | const char *symbol_name, | |
195 | uint64_t offset, | |
196 | uint64_t addr, | |
197 | struct lttng_event *event) | |
198 | { | |
199 | int ret; | |
200 | ||
201 | ret = lttng_create_kprobe_event(name, event); | |
202 | if (ret) | |
203 | goto error; | |
204 | ||
205 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
206 | &event->u.kprobe, lttng_kprobes_event_handler_pre); | |
207 | if (ret) | |
208 | goto register_error; | |
209 | ||
210 | return 0; | |
211 | ||
212 | register_error: | |
0d1a681e | 213 | kfree(event->desc->fields); |
f17701fb MD |
214 | kfree(event->desc->name); |
215 | kfree(event->desc); | |
216 | error: | |
217 | return ret; | |
218 | } | |
8bf17deb | 219 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 220 | |
2b16f0c9 FD |
221 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
222 | uint64_t offset, | |
223 | uint64_t addr, | |
224 | struct lttng_event_notifier *event_notifier) | |
225 | { | |
226 | int ret; | |
227 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
228 | if (ret) | |
229 | goto error; | |
230 | ||
231 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
232 | &event_notifier->u.kprobe, lttng_kprobes_event_notifier_handler_pre); | |
233 | if (ret) | |
234 | goto register_error; | |
235 | ||
236 | return 0; | |
237 | ||
238 | register_error: | |
239 | kfree(event_notifier->desc->name); | |
240 | kfree(event_notifier->desc); | |
241 | error: | |
242 | return ret; | |
243 | } | |
244 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
245 | ||
8bf17deb | 246 | void lttng_kprobes_unregister_event(struct lttng_event *event) |
f17701fb MD |
247 | { |
248 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 | 249 | } |
8bf17deb | 250 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 251 | |
2b16f0c9 FD |
252 | void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
253 | { | |
254 | unregister_kprobe(&event_notifier->u.kprobe.kp); | |
255 | } | |
256 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
257 | ||
8bf17deb | 258 | void lttng_kprobes_destroy_event_private(struct lttng_event *event) |
edeb3137 | 259 | { |
f17701fb | 260 | kfree(event->u.kprobe.symbol_name); |
0d1a681e | 261 | kfree(event->desc->fields); |
f17701fb MD |
262 | kfree(event->desc->name); |
263 | kfree(event->desc); | |
264 | } | |
8bf17deb | 265 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 266 | |
2b16f0c9 FD |
267 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
268 | { | |
269 | kfree(event_notifier->u.kprobe.symbol_name); | |
270 | kfree(event_notifier->desc->name); | |
271 | kfree(event_notifier->desc); | |
272 | } | |
273 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private); | |
274 | ||
d6d808f3 | 275 | MODULE_LICENSE("GPL and additional rights"); |
1c124020 MJ |
276 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
277 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
278 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
279 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
280 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
281 | LTTNG_MODULES_EXTRAVERSION); |