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); | |
57 | ||
58 | if (unlikely(!READ_ONCE(event_notifier->enabled))) | |
59 | return 0; | |
60 | ||
99d223ad | 61 | event_notifier->send_notification(event_notifier, NULL, NULL); |
2b16f0c9 FD |
62 | |
63 | return 0; | |
64 | } | |
65 | ||
f17701fb MD |
66 | /* |
67 | * Create event description | |
68 | */ | |
69 | static | |
a90917c3 | 70 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb MD |
71 | { |
72 | struct lttng_event_field *field; | |
d3dbe23c | 73 | struct lttng_event_desc *desc; |
f17701fb MD |
74 | int ret; |
75 | ||
d3dbe23c MD |
76 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
77 | if (!desc) | |
f17701fb | 78 | return -ENOMEM; |
d3dbe23c MD |
79 | desc->name = kstrdup(name, GFP_KERNEL); |
80 | if (!desc->name) { | |
f17701fb MD |
81 | ret = -ENOMEM; |
82 | goto error_str; | |
83 | } | |
d3dbe23c MD |
84 | desc->nr_fields = 1; |
85 | desc->fields = field = | |
f17701fb | 86 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
0d1a681e MD |
87 | if (!field) { |
88 | ret = -ENOMEM; | |
89 | goto error_field; | |
90 | } | |
f17701fb MD |
91 | field->name = "ip"; |
92 | field->type.atype = atype_integer; | |
ceabb767 MD |
93 | field->type.u.integer.size = sizeof(unsigned long) * CHAR_BIT; |
94 | field->type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; | |
95 | field->type.u.integer.signedness = lttng_is_signed_type(unsigned long); | |
96 | field->type.u.integer.reverse_byte_order = 0; | |
97 | field->type.u.integer.base = 16; | |
98 | field->type.u.integer.encoding = lttng_encode_none; | |
dc7f600a | 99 | desc->owner = THIS_MODULE; |
d3dbe23c | 100 | event->desc = desc; |
f17701fb MD |
101 | |
102 | return 0; | |
103 | ||
0d1a681e MD |
104 | error_field: |
105 | kfree(desc->name); | |
f17701fb | 106 | error_str: |
d3dbe23c | 107 | kfree(desc); |
f17701fb MD |
108 | return ret; |
109 | } | |
110 | ||
2b16f0c9 FD |
111 | /* |
112 | * Create event_notifier description | |
113 | */ | |
114 | static | |
115 | int lttng_create_kprobe_event_notifier(const char *name, struct lttng_event_notifier *event_notifier) | |
116 | { | |
117 | struct lttng_event_desc *desc; | |
118 | int ret; | |
119 | ||
120 | desc = kzalloc(sizeof(*event_notifier->desc), GFP_KERNEL); | |
121 | if (!desc) | |
122 | return -ENOMEM; | |
123 | desc->name = kstrdup(name, GFP_KERNEL); | |
124 | if (!desc->name) { | |
125 | ret = -ENOMEM; | |
126 | goto error_str; | |
127 | } | |
128 | desc->nr_fields = 0; | |
129 | ||
130 | desc->owner = THIS_MODULE; | |
131 | event_notifier->desc = desc; | |
132 | ||
133 | return 0; | |
134 | ||
135 | error_str: | |
136 | kfree(desc); | |
137 | return ret; | |
138 | } | |
139 | ||
8bf17deb FD |
140 | static |
141 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
142 | uint64_t offset, |
143 | uint64_t addr, | |
8bf17deb FD |
144 | struct lttng_kprobe *lttng_kp, |
145 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
146 | { |
147 | int ret; | |
148 | ||
c37f2a9b MD |
149 | /* Kprobes expects a NULL symbol name if unused */ |
150 | if (symbol_name[0] == '\0') | |
151 | symbol_name = NULL; | |
152 | ||
8bf17deb FD |
153 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
154 | lttng_kp->kp.pre_handler = pre_handler; | |
155 | ||
c37f2a9b | 156 | if (symbol_name) { |
8bf17deb | 157 | lttng_kp->symbol_name = |
f8695253 | 158 | kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 159 | GFP_KERNEL); |
8bf17deb | 160 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
161 | ret = -ENOMEM; |
162 | goto name_error; | |
163 | } | |
8bf17deb | 164 | memcpy(lttng_kp->symbol_name, symbol_name, |
f8695253 | 165 | LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 166 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 167 | } |
8bf17deb FD |
168 | |
169 | lttng_kp->kp.offset = offset; | |
170 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
171 | |
172 | /* | |
2b16f0c9 | 173 | * Ensure the memory we just allocated don't event_notifier page faults. |
16a9a591 MD |
174 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
175 | * but we can never be too careful. | |
176 | */ | |
263b6c88 | 177 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 178 | |
8bf17deb | 179 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
180 | if (ret) |
181 | goto register_error; | |
8bf17deb | 182 | |
f17701fb MD |
183 | return 0; |
184 | ||
185 | register_error: | |
8bf17deb | 186 | kfree(lttng_kp->symbol_name); |
f17701fb | 187 | name_error: |
8bf17deb FD |
188 | return ret; |
189 | } | |
190 | ||
191 | int lttng_kprobes_register_event(const char *name, | |
192 | const char *symbol_name, | |
193 | uint64_t offset, | |
194 | uint64_t addr, | |
195 | struct lttng_event *event) | |
196 | { | |
197 | int ret; | |
198 | ||
199 | ret = lttng_create_kprobe_event(name, event); | |
200 | if (ret) | |
201 | goto error; | |
202 | ||
203 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
204 | &event->u.kprobe, lttng_kprobes_event_handler_pre); | |
205 | if (ret) | |
206 | goto register_error; | |
207 | ||
208 | return 0; | |
209 | ||
210 | register_error: | |
0d1a681e | 211 | kfree(event->desc->fields); |
f17701fb MD |
212 | kfree(event->desc->name); |
213 | kfree(event->desc); | |
214 | error: | |
215 | return ret; | |
216 | } | |
8bf17deb | 217 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 218 | |
2b16f0c9 FD |
219 | int lttng_kprobes_register_event_notifier(const char *symbol_name, |
220 | uint64_t offset, | |
221 | uint64_t addr, | |
222 | struct lttng_event_notifier *event_notifier) | |
223 | { | |
224 | int ret; | |
225 | ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier); | |
226 | if (ret) | |
227 | goto error; | |
228 | ||
229 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
230 | &event_notifier->u.kprobe, lttng_kprobes_event_notifier_handler_pre); | |
231 | if (ret) | |
232 | goto register_error; | |
233 | ||
234 | return 0; | |
235 | ||
236 | register_error: | |
237 | kfree(event_notifier->desc->name); | |
238 | kfree(event_notifier->desc); | |
239 | error: | |
240 | return ret; | |
241 | } | |
242 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier); | |
243 | ||
8bf17deb | 244 | void lttng_kprobes_unregister_event(struct lttng_event *event) |
f17701fb MD |
245 | { |
246 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 | 247 | } |
8bf17deb | 248 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 249 | |
2b16f0c9 FD |
250 | void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier *event_notifier) |
251 | { | |
252 | unregister_kprobe(&event_notifier->u.kprobe.kp); | |
253 | } | |
254 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier); | |
255 | ||
8bf17deb | 256 | void lttng_kprobes_destroy_event_private(struct lttng_event *event) |
edeb3137 | 257 | { |
f17701fb | 258 | kfree(event->u.kprobe.symbol_name); |
0d1a681e | 259 | kfree(event->desc->fields); |
f17701fb MD |
260 | kfree(event->desc->name); |
261 | kfree(event->desc); | |
262 | } | |
8bf17deb | 263 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 | 264 | |
2b16f0c9 FD |
265 | void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier *event_notifier) |
266 | { | |
267 | kfree(event_notifier->u.kprobe.symbol_name); | |
268 | kfree(event_notifier->desc->name); | |
269 | kfree(event_notifier->desc); | |
270 | } | |
271 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private); | |
272 | ||
d6d808f3 | 273 | MODULE_LICENSE("GPL and additional rights"); |
1c124020 MJ |
274 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
275 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
276 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
277 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
278 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
279 | LTTNG_MODULES_EXTRAVERSION); |