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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only) |
8134eb60 | 2 | * |
149b9a9d YB |
3 | * probes/lttng-uprobes.c |
4 | * | |
5 | * LTTng uprobes integration module. | |
6 | * | |
7 | * Copyright (C) 2013 Yannick Brosseau <yannick.brosseau@gmail.com> | |
8 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
9 | * | |
149b9a9d YB |
10 | */ |
11 | ||
0aebcd68 | 12 | #include <wrapper/fdtable.h> |
3aed4dca | 13 | #include <linux/list.h> |
149b9a9d YB |
14 | #include <linux/module.h> |
15 | #include <linux/namei.h> | |
16 | #include <linux/slab.h> | |
3aed4dca | 17 | #include <linux/uaccess.h> |
2df37e95 | 18 | #include <lttng/events.h> |
a67ba386 | 19 | #include <lttng/events-internal.h> |
2df37e95 | 20 | #include <lttng/tracer.h> |
149b9a9d | 21 | #include <wrapper/irqflags.h> |
24591303 | 22 | #include <ringbuffer/frontend_types.h> |
149b9a9d YB |
23 | #include <wrapper/uprobes.h> |
24 | #include <wrapper/vmalloc.h> | |
25 | ||
26 | static | |
83b802dc | 27 | int lttng_uprobes_event_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs) |
149b9a9d | 28 | { |
3aed4dca FD |
29 | struct lttng_uprobe_handler *uprobe_handler = |
30 | container_of(uc, struct lttng_uprobe_handler, up_consumer); | |
e2d5dbc7 | 31 | struct lttng_kernel_event_common *event = uprobe_handler->event; |
a92e844e | 32 | struct lttng_kernel_probe_ctx lttng_probe_ctx = { |
e2d5dbc7 | 33 | .event = event, |
149b9a9d YB |
34 | .interruptible = !lttng_regs_irqs_disabled(regs), |
35 | }; | |
149b9a9d YB |
36 | struct { |
37 | unsigned long ip; | |
56377c91 | 38 | } payload; |
149b9a9d | 39 | |
e2d5dbc7 MD |
40 | switch (event->type) { |
41 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
42 | { | |
43 | struct lttng_kernel_event_recorder *event_recorder = | |
44 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
f7d06400 | 45 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e2d5dbc7 | 46 | |
f7d06400 | 47 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active))) |
e2d5dbc7 | 48 | return 0; |
f7d06400 | 49 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled))) |
e2d5dbc7 MD |
50 | return 0; |
51 | break; | |
52 | } | |
53 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
54 | break; | |
55 | default: | |
56 | WARN_ON_ONCE(1); | |
57 | } | |
9de67196 | 58 | |
e2d5dbc7 | 59 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
9de67196 FD |
60 | return 0; |
61 | ||
e2d5dbc7 MD |
62 | switch (event->type) { |
63 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
64 | { | |
65 | struct lttng_kernel_event_recorder *event_recorder = | |
66 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
f7d06400 | 67 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
8a57ec02 | 68 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
69 | int ret; |
70 | ||
b1199bd3 MD |
71 | lib_ring_buffer_ctx_init(&ctx, event_recorder, |
72 | sizeof(payload), lttng_alignof(payload), <tng_probe_ctx); | |
e2d5dbc7 | 73 | |
c2fb9c1c | 74 | ret = chan->ops->event_reserve(&ctx); |
e2d5dbc7 MD |
75 | if (ret < 0) |
76 | return 0; | |
77 | ||
78 | /* Event payload. */ | |
79 | payload.ip = (unsigned long)instruction_pointer(regs); | |
80 | ||
f5ffbd77 | 81 | chan->ops->event_write(&ctx, &payload, sizeof(payload), lttng_alignof(payload)); |
e2d5dbc7 MD |
82 | chan->ops->event_commit(&ctx); |
83 | break; | |
84 | } | |
85 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
86 | { | |
87 | struct lttng_kernel_event_notifier *event_notifier = | |
88 | container_of(event, struct lttng_kernel_event_notifier, parent); | |
89 | struct lttng_kernel_notification_ctx notif_ctx; | |
90 | ||
91 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); | |
92 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); | |
93 | break; | |
94 | } | |
95 | default: | |
96 | WARN_ON_ONCE(1); | |
97 | } | |
9de67196 FD |
98 | return 0; |
99 | } | |
100 | ||
6c8c025b MD |
101 | static const struct lttng_kernel_event_field *event_fields[] = { |
102 | lttng_kernel_static_event_field("ip", | |
103 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16), | |
104 | false, false, false), | |
105 | }; | |
106 | ||
107 | static const struct lttng_kernel_tracepoint_class tp_class = { | |
108 | .nr_fields = ARRAY_SIZE(event_fields), | |
109 | .fields = event_fields, | |
110 | }; | |
437d5aa5 | 111 | |
149b9a9d YB |
112 | /* |
113 | * Create event description. | |
114 | */ | |
115 | static | |
17806c46 | 116 | int lttng_create_uprobe_event(const char *name, struct lttng_kernel_event_common *event) |
149b9a9d | 117 | { |
437d5aa5 | 118 | struct lttng_kernel_event_desc *desc; |
149b9a9d YB |
119 | int ret; |
120 | ||
437d5aa5 | 121 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
149b9a9d YB |
122 | if (!desc) |
123 | return -ENOMEM; | |
6c8c025b | 124 | desc->tp_class = &tp_class; |
437d5aa5 MD |
125 | desc->event_name = kstrdup(name, GFP_KERNEL); |
126 | if (!desc->event_name) { | |
149b9a9d YB |
127 | ret = -ENOMEM; |
128 | goto error_str; | |
129 | } | |
149b9a9d | 130 | desc->owner = THIS_MODULE; |
17806c46 | 131 | event->priv->desc = desc; |
9de67196 FD |
132 | |
133 | return 0; | |
134 | ||
135 | error_str: | |
136 | kfree(desc); | |
137 | return ret; | |
138 | } | |
139 | ||
56377c91 FD |
140 | /* |
141 | * Returns the inode struct from the current task and an fd. The inode is | |
142 | * grabbed by this function and must be put once we are done with it using | |
143 | * iput(). | |
144 | */ | |
145 | static struct inode *get_inode_from_fd(int fd) | |
146 | { | |
147 | struct file *file; | |
148 | struct inode *inode; | |
149 | ||
150 | rcu_read_lock(); | |
151 | /* | |
152 | * Returns the file backing the given fd. Needs to be done inside an RCU | |
153 | * critical section. | |
154 | */ | |
0aebcd68 | 155 | file = lttng_lookup_fd_rcu(fd); |
56377c91 | 156 | if (file == NULL) { |
5a15f70c | 157 | printk(KERN_WARNING "LTTng: Cannot access file backing the fd(%d)\n", fd); |
56377c91 FD |
158 | inode = NULL; |
159 | goto error; | |
160 | } | |
161 | ||
162 | /* Grab a reference on the inode. */ | |
163 | inode = igrab(file->f_path.dentry->d_inode); | |
164 | if (inode == NULL) | |
5a15f70c | 165 | printk(KERN_WARNING "LTTng: Cannot grab a reference on the inode.\n"); |
56377c91 FD |
166 | error: |
167 | rcu_read_unlock(); | |
168 | return inode; | |
169 | } | |
170 | ||
83b802dc FD |
171 | |
172 | static | |
173 | int lttng_uprobes_add_callsite(struct lttng_uprobe *uprobe, | |
606828e4 | 174 | struct lttng_kernel_abi_event_callsite __user *callsite, |
83b802dc FD |
175 | int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs), |
176 | void *priv_data) | |
149b9a9d | 177 | { |
3aed4dca FD |
178 | int ret = 0; |
179 | struct lttng_uprobe_handler *uprobe_handler; | |
180 | ||
83b802dc | 181 | if (!priv_data) { |
3aed4dca FD |
182 | ret = -EINVAL; |
183 | goto end; | |
184 | } | |
185 | ||
186 | uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL); | |
187 | if (!uprobe_handler) { | |
5a15f70c | 188 | printk(KERN_WARNING "LTTng: Error allocating uprobe_handler"); |
3aed4dca FD |
189 | ret = -ENOMEM; |
190 | goto end; | |
191 | } | |
192 | ||
196bfc6a | 193 | /* Ensure the memory we just allocated don't notify page faults. */ |
263b6c88 | 194 | wrapper_vmalloc_sync_mappings(); |
3aed4dca | 195 | |
e2d5dbc7 | 196 | uprobe_handler->event = priv_data; |
83b802dc | 197 | uprobe_handler->up_consumer.handler = handler; |
3aed4dca FD |
198 | |
199 | ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t)); | |
200 | if (ret) { | |
201 | goto register_error; | |
202 | } | |
203 | ||
83b802dc | 204 | ret = wrapper_uprobe_register(uprobe->inode, |
3aed4dca FD |
205 | uprobe_handler->offset, &uprobe_handler->up_consumer); |
206 | if (ret) { | |
5a15f70c | 207 | printk(KERN_WARNING "LTTng: Error registering probe on inode %lu " |
83b802dc | 208 | "and offset 0x%llx\n", uprobe->inode->i_ino, |
3aed4dca FD |
209 | uprobe_handler->offset); |
210 | ret = -1; | |
211 | goto register_error; | |
212 | } | |
213 | ||
83b802dc | 214 | list_add(&uprobe_handler->node, &uprobe->head); |
3aed4dca FD |
215 | |
216 | return ret; | |
217 | ||
218 | register_error: | |
219 | kfree(uprobe_handler); | |
220 | end: | |
221 | return ret; | |
222 | } | |
3aed4dca | 223 | |
e2d5dbc7 | 224 | int lttng_uprobes_event_add_callsite(struct lttng_kernel_event_common *event, |
606828e4 | 225 | struct lttng_kernel_abi_event_callsite __user *callsite) |
83b802dc | 226 | { |
e2d5dbc7 MD |
227 | return lttng_uprobes_add_callsite(&event->priv->u.uprobe, callsite, |
228 | lttng_uprobes_event_handler_pre, event); | |
83b802dc FD |
229 | } |
230 | EXPORT_SYMBOL_GPL(lttng_uprobes_event_add_callsite); | |
231 | ||
232 | static | |
233 | int lttng_uprobes_register(struct lttng_uprobe *uprobe, int fd) | |
3aed4dca FD |
234 | { |
235 | int ret = 0; | |
56377c91 | 236 | struct inode *inode; |
149b9a9d | 237 | |
56377c91 FD |
238 | inode = get_inode_from_fd(fd); |
239 | if (!inode) { | |
5a15f70c | 240 | printk(KERN_WARNING "LTTng: Cannot get inode from fd\n"); |
56377c91 FD |
241 | ret = -EBADF; |
242 | goto inode_error; | |
243 | } | |
83b802dc FD |
244 | uprobe->inode = inode; |
245 | INIT_LIST_HEAD(&uprobe->head); | |
246 | ||
247 | inode_error: | |
248 | return ret; | |
249 | } | |
250 | ||
17806c46 | 251 | int lttng_uprobes_register_event(const char *name, int fd, struct lttng_kernel_event_common *event) |
83b802dc FD |
252 | { |
253 | int ret = 0; | |
254 | ||
17806c46 | 255 | ret = lttng_create_uprobe_event(name, event); |
83b802dc FD |
256 | if (ret) |
257 | goto error; | |
258 | ||
17806c46 | 259 | ret = lttng_uprobes_register(&event->priv->u.uprobe, fd); |
83b802dc FD |
260 | if (ret) |
261 | goto register_error; | |
149b9a9d | 262 | |
149b9a9d YB |
263 | return 0; |
264 | ||
83b802dc | 265 | register_error: |
17806c46 MD |
266 | kfree(event->priv->desc->event_name); |
267 | kfree(event->priv->desc); | |
149b9a9d YB |
268 | error: |
269 | return ret; | |
270 | } | |
83b802dc | 271 | EXPORT_SYMBOL_GPL(lttng_uprobes_register_event); |
149b9a9d | 272 | |
9de67196 FD |
273 | static |
274 | void lttng_uprobes_unregister(struct inode *inode, struct list_head *head) | |
149b9a9d | 275 | { |
3aed4dca FD |
276 | struct lttng_uprobe_handler *iter, *tmp; |
277 | ||
278 | /* | |
279 | * Iterate over the list of handler, remove each handler from the list | |
280 | * and free the struct. | |
281 | */ | |
9de67196 FD |
282 | list_for_each_entry_safe(iter, tmp, head, node) { |
283 | wrapper_uprobe_unregister(inode, iter->offset, &iter->up_consumer); | |
3aed4dca FD |
284 | list_del(&iter->node); |
285 | kfree(iter); | |
286 | } | |
9de67196 FD |
287 | } |
288 | ||
17806c46 | 289 | void lttng_uprobes_unregister_event(struct lttng_kernel_event_common *event) |
9de67196 | 290 | { |
17806c46 | 291 | lttng_uprobes_unregister(event->priv->u.uprobe.inode, &event->priv->u.uprobe.head); |
149b9a9d | 292 | } |
83b802dc | 293 | EXPORT_SYMBOL_GPL(lttng_uprobes_unregister_event); |
149b9a9d | 294 | |
17806c46 | 295 | void lttng_uprobes_destroy_event_private(struct lttng_kernel_event_common *event) |
149b9a9d | 296 | { |
17806c46 MD |
297 | iput(event->priv->u.uprobe.inode); |
298 | kfree(event->priv->desc->event_name); | |
299 | kfree(event->priv->desc); | |
149b9a9d | 300 | } |
83b802dc | 301 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_private); |
149b9a9d | 302 | |
a67ba386 | 303 | void lttng_uprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier) |
9de67196 | 304 | { |
a67ba386 MD |
305 | iput(event_notifier->priv->parent.u.uprobe.inode); |
306 | kfree(event_notifier->priv->parent.desc->event_name); | |
307 | kfree(event_notifier->priv->parent.desc); | |
9de67196 FD |
308 | } |
309 | EXPORT_SYMBOL_GPL(lttng_uprobes_destroy_event_notifier_private); | |
310 | ||
149b9a9d YB |
311 | MODULE_LICENSE("GPL and additional rights"); |
312 | MODULE_AUTHOR("Yannick Brosseau"); | |
313 | MODULE_DESCRIPTION("Linux Trace Toolkit Uprobes Support"); |