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
);
69 * Create event description
72 int lttng_create_kprobe_event(const char *name
, struct lttng_event
*event
)
74 struct lttng_event_field
*field
;
75 struct lttng_event_desc
*desc
;
78 desc
= kzalloc(sizeof(*event
->desc
), GFP_KERNEL
);
81 desc
->name
= kstrdup(name
, GFP_KERNEL
);
87 desc
->fields
= field
=
88 kzalloc(1 * sizeof(struct lttng_event_field
), GFP_KERNEL
);
94 field
->type
.atype
= atype_integer
;
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
;
101 desc
->owner
= THIS_MODULE
;
114 * Create event_notifier description
117 int lttng_create_kprobe_event_notifier(const char *name
, struct lttng_event_notifier
*event_notifier
)
119 struct lttng_event_desc
*desc
;
122 desc
= kzalloc(sizeof(*event_notifier
->desc
), GFP_KERNEL
);
125 desc
->name
= kstrdup(name
, GFP_KERNEL
);
132 desc
->owner
= THIS_MODULE
;
133 event_notifier
->desc
= desc
;
143 int _lttng_kprobes_register(const char *symbol_name
,
146 struct lttng_kprobe
*lttng_kp
,
147 kprobe_pre_handler_t pre_handler
)
151 /* Kprobes expects a NULL symbol name if unused */
152 if (symbol_name
[0] == '\0')
155 memset(<tng_kp
->kp
, 0, sizeof(lttng_kp
->kp
));
156 lttng_kp
->kp
.pre_handler
= pre_handler
;
159 lttng_kp
->symbol_name
=
160 kzalloc(LTTNG_KERNEL_SYM_NAME_LEN
* sizeof(char),
162 if (!lttng_kp
->symbol_name
) {
166 memcpy(lttng_kp
->symbol_name
, symbol_name
,
167 LTTNG_KERNEL_SYM_NAME_LEN
* sizeof(char));
168 lttng_kp
->kp
.symbol_name
= lttng_kp
->symbol_name
;
171 lttng_kp
->kp
.offset
= offset
;
172 lttng_kp
->kp
.addr
= (void *) (unsigned long) addr
;
175 * Ensure the memory we just allocated don't event_notifier page faults.
176 * Well.. kprobes itself puts the page fault handler on the blacklist,
177 * but we can never be too careful.
179 wrapper_vmalloc_sync_mappings();
181 ret
= register_kprobe(<tng_kp
->kp
);
188 kfree(lttng_kp
->symbol_name
);
193 int lttng_kprobes_register_event(const char *name
,
194 const char *symbol_name
,
197 struct lttng_event
*event
)
201 ret
= lttng_create_kprobe_event(name
, event
);
205 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
206 &event
->u
.kprobe
, lttng_kprobes_event_handler_pre
);
213 kfree(event
->desc
->fields
);
214 kfree(event
->desc
->name
);
219 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event
);
221 int lttng_kprobes_register_event_notifier(const char *symbol_name
,
224 struct lttng_event_notifier
*event_notifier
)
227 ret
= lttng_create_kprobe_event_notifier(symbol_name
, event_notifier
);
231 ret
= _lttng_kprobes_register(symbol_name
, offset
, addr
,
232 &event_notifier
->u
.kprobe
, lttng_kprobes_event_notifier_handler_pre
);
239 kfree(event_notifier
->desc
->name
);
240 kfree(event_notifier
->desc
);
244 EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier
);
246 void lttng_kprobes_unregister_event(struct lttng_event
*event
)
248 unregister_kprobe(&event
->u
.kprobe
.kp
);
250 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event
);
252 void lttng_kprobes_unregister_event_notifier(struct lttng_event_notifier
*event_notifier
)
254 unregister_kprobe(&event_notifier
->u
.kprobe
.kp
);
256 EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier
);
258 void lttng_kprobes_destroy_event_private(struct lttng_event
*event
)
260 kfree(event
->u
.kprobe
.symbol_name
);
261 kfree(event
->desc
->fields
);
262 kfree(event
->desc
->name
);
265 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private
);
267 void lttng_kprobes_destroy_event_notifier_private(struct lttng_event_notifier
*event_notifier
)
269 kfree(event_notifier
->u
.kprobe
.symbol_name
);
270 kfree(event_notifier
->desc
->name
);
271 kfree(event_notifier
->desc
);
273 EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private
);
275 MODULE_LICENSE("GPL and additional rights");
276 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
277 MODULE_DESCRIPTION("LTTng kprobes probes");
278 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
279 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
280 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
281 LTTNG_MODULES_EXTRAVERSION
);