1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
3 * probes/lttng-kprobes.c
5 * LTTng kprobes integration module.
7 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 #include <linux/module.h>
11 #include <linux/kprobes.h>
12 #include <linux/slab.h>
13 #include <lttng/events.h>
14 #include <ringbuffer/frontend_types.h>
15 #include <wrapper/vmalloc.h>
16 #include <wrapper/irqflags.h>
17 #include <lttng/tracer.h>
18 #include <blacklist/kprobes.h>
21 int lttng_kprobes_event_handler_pre(struct kprobe
*p
, struct pt_regs
*regs
)
23 struct lttng_event
*event
=
24 container_of(p
, struct lttng_event
, u
.kprobe
.kp
);
25 struct lttng_probe_ctx lttng_probe_ctx
= {
27 .interruptible
= !lttng_regs_irqs_disabled(regs
),
29 struct lttng_channel
*chan
= event
->chan
;
30 struct lib_ring_buffer_ctx ctx
;
32 unsigned long data
= (unsigned long) p
->addr
;
34 if (unlikely(!LTTNG_READ_ONCE(chan
->session
->active
)))
36 if (unlikely(!LTTNG_READ_ONCE(chan
->enabled
)))
38 if (unlikely(!LTTNG_READ_ONCE(event
->enabled
)))
41 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, <tng_probe_ctx
, sizeof(data
),
42 lttng_alignof(data
), -1);
43 ret
= chan
->ops
->event_reserve(&ctx
, event
->id
);
46 lib_ring_buffer_align_ctx(&ctx
, lttng_alignof(data
));
47 chan
->ops
->event_write(&ctx
, &data
, sizeof(data
));
48 chan
->ops
->event_commit(&ctx
);
53 int lttng_kprobes_event_notifier_handler_pre(struct kprobe
*p
, struct pt_regs
*regs
)
55 struct lttng_event_notifier
*event_notifier
=
56 container_of(p
, struct lttng_event_notifier
, u
.kprobe
.kp
);
57 struct lttng_kernel_notifier_ctx notif_ctx
;
59 if (unlikely(!READ_ONCE(event_notifier
->enabled
)))
62 notif_ctx
.eval_capture
= LTTNG_READ_ONCE(event_notifier
->eval_capture
);
63 event_notifier
->send_notification(event_notifier
, NULL
, NULL
, ¬if_ctx
);
68 static const struct lttng_kernel_type_common
*event_type
=
69 lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER
, 16);
72 * Create event description
75 int lttng_create_kprobe_event(const char *name
, struct lttng_event
*event
)
77 const struct lttng_kernel_event_field
**fieldp_array
;
78 struct lttng_kernel_event_field
*field
;
79 struct lttng_kernel_event_desc
*desc
;
82 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
85 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
86 if (!desc
->event_name
) {
91 fieldp_array
= kzalloc(1 * sizeof(struct lttng_kernel_event_field
*), GFP_KERNEL
);
94 goto error_fieldp_array
;
96 desc
->fields
= fieldp_array
;
97 desc
->fields
[0] = field
=
98 kzalloc(sizeof(struct lttng_kernel_event_field
), GFP_KERNEL
);
104 field
->type
= event_type
;
105 desc
->owner
= THIS_MODULE
;
113 kfree(desc
->event_name
);
120 * Create event_notifier description
123 int lttng_create_kprobe_event_notifier(const char *name
, struct lttng_event_notifier
*event_notifier
)
125 struct lttng_kernel_event_desc
*desc
;
128 desc
= kzalloc(sizeof(*desc
), GFP_KERNEL
);
131 desc
->event_name
= kstrdup(name
, GFP_KERNEL
);
132 if (!desc
->event_name
) {
138 desc
->owner
= THIS_MODULE
;
139 event_notifier
->desc
= desc
;
149 int _lttng_kprobes_register(const char *symbol_name
,
152 struct lttng_kprobe
*lttng_kp
,
153 kprobe_pre_handler_t pre_handler
)
157 /* Kprobes expects a NULL symbol name if unused */
158 if (symbol_name
[0] == '\0')
161 memset(<tng_kp
->kp
, 0, sizeof(lttng_kp
->kp
));
162 lttng_kp
->kp
.pre_handler
= pre_handler
;
165 lttng_kp
->symbol_name
=
166 kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN
* sizeof(char),
168 if (!lttng_kp
->symbol_name
) {
172 memcpy(lttng_kp
->symbol_name
, symbol_name
,
173 LTTNG_KERNEL_ABI_SYM_NAME_LEN
* sizeof(char));
174 lttng_kp
->kp
.symbol_name
= lttng_kp
->symbol_name
;
177 lttng_kp
->kp
.offset
= offset
;
178 lttng_kp
->kp
.addr
= (void *) (unsigned long) addr
;
181 * Ensure the memory we just allocated don't notify page faults.
182 * Well.. kprobes itself puts the page fault handler on the blacklist,
183 * but we can never be too careful.
185 wrapper_vmalloc_sync_mappings();
187 ret
= register_kprobe(<tng_kp
->kp
);
194 kfree(lttng_kp
->symbol_name
);
199 int lttng_kprobes_register_event(const char *name
,
200 const char *symbol_name
,
203 struct lttng_event
*event
)
207 ret
= lttng_create_kprobe_event(name
, event
);
211 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
212 &event
->u
.kprobe
, lttng_kprobes_event_handler_pre
);
219 kfree(event
->desc
->fields
);
220 kfree(event
->desc
->event_name
);
225 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event
);
227 int lttng_kprobes_register_event_notifier(const char *symbol_name
,
230 struct lttng_event_notifier
*event_notifier
)
233 ret
= lttng_create_kprobe_event_notifier(symbol_name
, event_notifier
);
237 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
238 &event_notifier
->u
.kprobe
, lttng_kprobes_event_notifier_handler_pre
);
245 kfree(event_notifier
->desc
->event_name
);
246 kfree(event_notifier
->desc
);
250 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier
);
252 void lttng_kprobes_unregister_event(struct lttng_event
*event
)
254 unregister_kprobe(&event
->u
.kprobe
.kp
);
256 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event
);
258 void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier
*event_notifier
)
260 unregister_kprobe(&event_notifier
->u
.kprobe
.kp
);
262 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier
);
264 void lttng_kprobes_destroy_event_private(struct lttng_event
*event
)
266 kfree(event
->u
.kprobe
.symbol_name
);
267 kfree(event
->desc
->fields
[0]);
268 kfree(event
->desc
->fields
);
269 kfree(event
->desc
->event_name
);
272 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private
);
274 void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier
*event_notifier
)
276 kfree(event_notifier
->u
.kprobe
.symbol_name
);
277 kfree(event_notifier
->desc
->event_name
);
278 kfree(event_notifier
->desc
);
280 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private
);
282 MODULE_LICENSE("GPL and additional rights");
283 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
284 MODULE_DESCRIPTION("LTTng kprobes probes");
285 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
286 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
287 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
288 LTTNG_MODULES_EXTRAVERSION
);