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_event_container
*container
= event
->container
;
31 unsigned long data
= (unsigned long) p
->addr
;
33 if (unlikely(!LTTNG_READ_ONCE(container
->session
->active
)))
35 if (unlikely(!LTTNG_READ_ONCE(container
->enabled
)))
37 if (unlikely(!LTTNG_READ_ONCE(event
->enabled
)))
40 switch (container
->type
) {
41 case LTTNG_EVENT_CONTAINER_CHANNEL
:
43 struct lttng_channel
*chan
= lttng_event_container_get_channel(container
);
44 struct lib_ring_buffer_ctx ctx
;
46 lib_ring_buffer_ctx_init(&ctx
, chan
->chan
, <tng_probe_ctx
, sizeof(data
),
47 lttng_alignof(data
), -1);
48 ret
= chan
->ops
->event_reserve(&ctx
, event
->id
);
51 lib_ring_buffer_align_ctx(&ctx
, lttng_alignof(data
));
52 chan
->ops
->event_write(&ctx
, &data
, sizeof(data
));
53 chan
->ops
->event_commit(&ctx
);
56 case LTTNG_EVENT_CONTAINER_COUNTER
:
58 struct lttng_counter
*counter
= lttng_event_container_get_counter(container
);
59 size_t index
= event
->id
;
61 (void) counter
->ops
->counter_add(counter
->counter
, &index
, 1);
69 int lttng_kprobes_event_notifier_handler_pre(struct kprobe
*p
, struct pt_regs
*regs
)
71 struct lttng_event_notifier
*event_notifier
=
72 container_of(p
, struct lttng_event_notifier
, u
.kprobe
.kp
);
73 struct lttng_kernel_notifier_ctx notif_ctx
;
75 if (unlikely(!READ_ONCE(event_notifier
->enabled
)))
78 notif_ctx
.eval_capture
= LTTNG_READ_ONCE(event_notifier
->eval_capture
);
79 event_notifier
->send_notification(event_notifier
, NULL
, NULL
, ¬if_ctx
);
85 * Create event description
88 int lttng_create_kprobe_event(const char *name
, struct lttng_event
*event
)
90 struct lttng_event_field
*field
;
91 struct lttng_event_desc
*desc
;
94 desc
= kzalloc(sizeof(*event
->desc
), GFP_KERNEL
);
97 desc
->name
= kstrdup(name
, GFP_KERNEL
);
103 desc
->fields
= field
=
104 kzalloc(1 * sizeof(struct lttng_event_field
), GFP_KERNEL
);
110 field
->type
.atype
= atype_integer
;
111 field
->type
.u
.integer
.size
= sizeof(unsigned long) * CHAR_BIT
;
112 field
->type
.u
.integer
.alignment
= lttng_alignof(unsigned long) * CHAR_BIT
;
113 field
->type
.u
.integer
.signedness
= lttng_is_signed_type(unsigned long);
114 field
->type
.u
.integer
.reverse_byte_order
= 0;
115 field
->type
.u
.integer
.base
= 16;
116 field
->type
.u
.integer
.encoding
= lttng_encode_none
;
117 desc
->owner
= THIS_MODULE
;
130 * Create event_notifier description
133 int lttng_create_kprobe_event_notifier(const char *name
, struct lttng_event_notifier
*event_notifier
)
135 struct lttng_event_desc
*desc
;
138 desc
= kzalloc(sizeof(*event_notifier
->desc
), GFP_KERNEL
);
141 desc
->name
= kstrdup(name
, GFP_KERNEL
);
148 desc
->owner
= THIS_MODULE
;
149 event_notifier
->desc
= desc
;
159 int _lttng_kprobes_register(const char *symbol_name
,
162 struct lttng_kprobe
*lttng_kp
,
163 kprobe_pre_handler_t pre_handler
)
167 /* Kprobes expects a NULL symbol name if unused */
168 if (symbol_name
[0] == '\0')
171 memset(<tng_kp
->kp
, 0, sizeof(lttng_kp
->kp
));
172 lttng_kp
->kp
.pre_handler
= pre_handler
;
175 lttng_kp
->symbol_name
=
176 kzalloc(LTTNG_KERNEL_SYM_NAME_LEN
* sizeof(char),
178 if (!lttng_kp
->symbol_name
) {
182 memcpy(lttng_kp
->symbol_name
, symbol_name
,
183 LTTNG_KERNEL_SYM_NAME_LEN
* sizeof(char));
184 lttng_kp
->kp
.symbol_name
= lttng_kp
->symbol_name
;
187 lttng_kp
->kp
.offset
= offset
;
188 lttng_kp
->kp
.addr
= (void *) (unsigned long) addr
;
191 * Ensure the memory we just allocated don't event_notifier page faults.
192 * Well.. kprobes itself puts the page fault handler on the blacklist,
193 * but we can never be too careful.
195 wrapper_vmalloc_sync_mappings();
197 ret
= register_kprobe(<tng_kp
->kp
);
204 kfree(lttng_kp
->symbol_name
);
209 int lttng_kprobes_register_event(const char *name
,
210 const char *symbol_name
,
213 struct lttng_event
*event
)
217 ret
= lttng_create_kprobe_event(name
, event
);
221 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
222 &event
->u
.kprobe
, lttng_kprobes_event_handler_pre
);
229 kfree(event
->desc
->fields
);
230 kfree(event
->desc
->name
);
235 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event
);
237 int lttng_kprobes_register_event_notifier(const char *symbol_name
,
240 struct lttng_event_notifier
*event_notifier
)
243 ret
= lttng_create_kprobe_event_notifier(symbol_name
, event_notifier
);
247 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
248 &event_notifier
->u
.kprobe
, lttng_kprobes_event_notifier_handler_pre
);
255 kfree(event_notifier
->desc
->name
);
256 kfree(event_notifier
->desc
);
260 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier
);
262 void lttng_kprobes_unregister_event(struct lttng_event
*event
)
264 unregister_kprobe(&event
->u
.kprobe
.kp
);
266 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event
);
268 void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier
*event_notifier
)
270 unregister_kprobe(&event_notifier
->u
.kprobe
.kp
);
272 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier
);
274 void lttng_kprobes_destroy_event_private(struct lttng_event
*event
)
276 kfree(event
->u
.kprobe
.symbol_name
);
277 kfree(event
->desc
->fields
);
278 kfree(event
->desc
->name
);
281 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private
);
283 void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier
*event_notifier
)
285 kfree(event_notifier
->u
.kprobe
.symbol_name
);
286 kfree(event_notifier
->desc
->name
);
287 kfree(event_notifier
->desc
);
289 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private
);
291 MODULE_LICENSE("GPL and additional rights");
292 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
293 MODULE_DESCRIPTION("LTTng kprobes probes");
294 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
295 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
296 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
297 LTTNG_MODULES_EXTRAVERSION
);