[lttng-modules.git] / src / probes / lttng-kprobes.c

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * probes/lttng-kprobes.c
 *
 * LTTng kprobes integration module.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/slab.h>
#include <lttng/events.h>
#include <lttng/events-internal.h>
#include <ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <wrapper/irqflags.h>
#include <lttng/tracer.h>
#include <blacklist/kprobes.h>

static
int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
	struct lttng_kernel_event_common_private *event_priv =
		container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp);
	struct lttng_kernel_event_common *event = event_priv->pub;
	struct lttng_kernel_probe_ctx lttng_probe_ctx = {
		.event = event,
		.interruptible = !lttng_regs_irqs_disabled(regs),
	};
	unsigned long data = (unsigned long) p->addr;

	switch (event->type) {
	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
	{
		struct lttng_kernel_event_recorder_private *event_recorder_priv =
			container_of(event_priv, struct lttng_kernel_event_recorder_private, parent);
		struct lttng_kernel_event_recorder *event_recorder =
			event_recorder_priv->pub;
		struct lttng_kernel_channel_buffer *chan = event_recorder->chan;

		if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active)))
			return 0;
		if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled)))
			return 0;
		break;
	}
	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
		break;
	default:
		WARN_ON_ONCE(1);
	}

	if (unlikely(!LTTNG_READ_ONCE(event->enabled)))
		return 0;

	switch (event->type) {
	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
	{
		struct lttng_kernel_event_recorder *event_recorder =
			container_of(event, struct lttng_kernel_event_recorder, parent);
		struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
		struct lttng_kernel_ring_buffer_ctx ctx;
		int ret;

		lib_ring_buffer_ctx_init(&ctx, event_recorder, sizeof(data),
					 lttng_alignof(data), &lttng_probe_ctx);
		ret = chan->ops->event_reserve(&ctx);
		if (ret < 0)
			return 0;
		lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data));
		chan->ops->event_write(&ctx, &data, sizeof(data));
		chan->ops->event_commit(&ctx);
		break;
	}
	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
	{
		struct lttng_kernel_event_notifier *event_notifier =
			container_of(event, struct lttng_kernel_event_notifier, parent);
		struct lttng_kernel_notification_ctx notif_ctx;

		notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture);
		event_notifier->notification_send(event_notifier, NULL, NULL, &notif_ctx);
		break;
	}
	default:
		WARN_ON_ONCE(1);
	}
	return 0;
}

static const struct lttng_kernel_event_field *event_fields[] = {
	lttng_kernel_static_event_field("ip",
		lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16),
		false, false, false),
};

static const struct lttng_kernel_tracepoint_class tp_class = {
	.nr_fields = ARRAY_SIZE(event_fields),
	.fields = event_fields,
};

/*
 * Create event description
 */
static
int lttng_create_kprobe_event(const char *name, struct lttng_kernel_event_recorder *event_recorder)
{
	struct lttng_kernel_event_desc *desc;
	int ret;

	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
	if (!desc)
		return -ENOMEM;
	desc->tp_class = &tp_class;
	desc->event_name = kstrdup(name, GFP_KERNEL);
	if (!desc->event_name) {
		ret = -ENOMEM;
		goto error_str;
	}
	desc->owner = THIS_MODULE;
	event_recorder->priv->parent.desc = desc;

	return 0;

error_str:
	kfree(desc);
	return ret;
}

/*
 * Create event_notifier description
 */
static
int lttng_create_kprobe_event_notifier(const char *name, struct lttng_kernel_event_notifier *event_notifier)
{
	struct lttng_kernel_event_desc *desc;
	int ret;

	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
	if (!desc)
		return -ENOMEM;
	desc->tp_class = &tp_class;
	desc->event_name = kstrdup(name, GFP_KERNEL);
	if (!desc->event_name) {
		ret = -ENOMEM;
		goto error_str;
	}
	desc->owner = THIS_MODULE;
	event_notifier->priv->parent.desc = desc;

	return 0;

error_str:
	kfree(desc);
	return ret;
}

static
int _lttng_kprobes_register(const char *symbol_name,
			   uint64_t offset,
			   uint64_t addr,
			   struct lttng_kprobe *lttng_kp,
			   kprobe_pre_handler_t pre_handler)
{
	int ret;

	/* Kprobes expects a NULL symbol name if unused */
	if (symbol_name[0] == '\0')
		symbol_name = NULL;

	memset(&lttng_kp->kp, 0, sizeof(lttng_kp->kp));
	lttng_kp->kp.pre_handler = pre_handler;

	if (symbol_name) {
		lttng_kp->symbol_name =
			kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char),
				GFP_KERNEL);
		if (!lttng_kp->symbol_name) {
			ret = -ENOMEM;
			goto name_error;
		}
		memcpy(lttng_kp->symbol_name, symbol_name,
		       LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char));
		lttng_kp->kp.symbol_name = lttng_kp->symbol_name;
	}

	lttng_kp->kp.offset = offset;
	lttng_kp->kp.addr = (void *) (unsigned long) addr;

	/*
	 * Ensure the memory we just allocated don't notify page faults.
	 * Well.. kprobes itself puts the page fault handler on the blacklist,
	 * but we can never be too careful.
	 */
	wrapper_vmalloc_sync_mappings();

	ret = register_kprobe(&lttng_kp->kp);
	if (ret)
		goto register_error;

	return 0;

register_error:
	kfree(lttng_kp->symbol_name);
name_error:
	return ret;
}

int lttng_kprobes_register_event(const char *name,
			   const char *symbol_name,
			   uint64_t offset,
			   uint64_t addr,
			   struct lttng_kernel_event_recorder *event_recorder)
{
	int ret;

	ret = lttng_create_kprobe_event(name, event_recorder);
	if (ret)
		goto error;

	ret = _lttng_kprobes_register(symbol_name, offset, addr,
		&event_recorder->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre);
	if (ret)
		goto register_error;

	return 0;

register_error:
	kfree(event_recorder->priv->parent.desc->event_name);
	kfree(event_recorder->priv->parent.desc);
error:
	return ret;
}
EXPORT_SYMBOL_GPL(lttng_kprobes_register_event);

int lttng_kprobes_register_event_notifier(const char *symbol_name,
			   uint64_t offset,
			   uint64_t addr,
			   struct lttng_kernel_event_notifier *event_notifier)
{
	int ret;
	ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier);
	if (ret)
		goto error;

	ret = _lttng_kprobes_register(symbol_name, offset, addr,
		&event_notifier->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre);
	if (ret)
		goto register_error;

	return 0;

register_error:
	kfree(event_notifier->priv->parent.desc->event_name);
	kfree(event_notifier->priv->parent.desc);
error:
	return ret;
}
EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier);

void lttng_kprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder)
{
	unregister_kprobe(&event_recorder->priv->parent.u.kprobe.kp);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event);

void lttng_kprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier)
{
	unregister_kprobe(&event_notifier->priv->parent.u.kprobe.kp);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier);

void lttng_kprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder)
{
	kfree(event_recorder->priv->parent.u.kprobe.symbol_name);
	kfree(event_recorder->priv->parent.desc->event_name);
	kfree(event_recorder->priv->parent.desc);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private);

void lttng_kprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier)
{
	kfree(event_notifier->priv->parent.u.kprobe.symbol_name);
	kfree(event_notifier->priv->parent.desc->event_name);
	kfree(event_notifier->priv->parent.desc);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
MODULE_DESCRIPTION("LTTng kprobes probes");
MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	LTTNG_MODULES_EXTRAVERSION);
Commit	Line	Data
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>
a67ba386	14	#include <lttng/events-internal.h>
24591303	15	#include <ringbuffer/frontend_types.h>
156a3977 MD	16	#include <wrapper/vmalloc.h>
156a3977 MD	17	#include <wrapper/irqflags.h>
2df37e95	18	#include <lttng/tracer.h>
caa068b5	19	#include <blacklist/kprobes.h>
d6d808f3	20
f17701fb	21	static
8bf17deb	22	int lttng_kprobes_event_handler_pre(struct kprobe p, struct pt_regs regs)
d6d808f3	23	{
a67ba386 MD	24	struct lttng_kernel_event_common_private *event_priv =
a67ba386 MD	25	container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp);
e2d5dbc7	26	struct lttng_kernel_event_common *event = event_priv->pub;
a92e844e	27	struct lttng_kernel_probe_ctx lttng_probe_ctx = {
e2d5dbc7	28	.event = event,
ccecf3fb	29	.interruptible = !lttng_regs_irqs_disabled(regs),
79150a49	30	};
d6d808f3 MD	31	unsigned long data = (unsigned long) p->addr;
d6d808f3 MD	32
e2d5dbc7 MD	33	switch (event->type) {
	34	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
	35	{
	36	struct lttng_kernel_event_recorder_private *event_recorder_priv =
	37	container_of(event_priv, struct lttng_kernel_event_recorder_private, parent);
	38	struct lttng_kernel_event_recorder *event_recorder =
	39	event_recorder_priv->pub;
f7d06400	40	struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
e2d5dbc7	41
f7d06400	42	if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active)))
e2d5dbc7	43	return 0;
f7d06400	44	if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled)))
e2d5dbc7 MD	45	return 0;
	46	break;
	47	}
	48	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
	49	break;
	50	default:
	51	WARN_ON_ONCE(1);
	52	}
a67ba386	53
e2d5dbc7	54	if (unlikely(!LTTNG_READ_ONCE(event->enabled)))
2b16f0c9 FD	55	return 0;
2b16f0c9 FD	56
e2d5dbc7 MD	57	switch (event->type) {
	58	case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
	59	{
	60	struct lttng_kernel_event_recorder *event_recorder =
	61	container_of(event, struct lttng_kernel_event_recorder, parent);
f7d06400	62	struct lttng_kernel_channel_buffer *chan = event_recorder->chan;
8a57ec02	63	struct lttng_kernel_ring_buffer_ctx ctx;
e2d5dbc7 MD	64	int ret;
e2d5dbc7 MD	65
b1199bd3 MD	66	lib_ring_buffer_ctx_init(&ctx, event_recorder, sizeof(data),
b1199bd3 MD	67	lttng_alignof(data), &lttng_probe_ctx);
c2fb9c1c	68	ret = chan->ops->event_reserve(&ctx);
e2d5dbc7 MD	69	if (ret < 0)
	70	return 0;
	71	lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data));
	72	chan->ops->event_write(&ctx, &data, sizeof(data));
	73	chan->ops->event_commit(&ctx);
	74	break;
	75	}
	76	case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
	77	{
	78	struct lttng_kernel_event_notifier *event_notifier =
	79	container_of(event, struct lttng_kernel_event_notifier, parent);
	80	struct lttng_kernel_notification_ctx notif_ctx;
	81
	82	notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture);
	83	event_notifier->notification_send(event_notifier, NULL, NULL, &notif_ctx);
	84	break;
	85	}
	86	default:
	87	WARN_ON_ONCE(1);
	88	}
2b16f0c9 FD	89	return 0;
	90	}
	91
6c8c025b MD	92	static const struct lttng_kernel_event_field *event_fields[] = {
	93	lttng_kernel_static_event_field("ip",
	94	lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16),
	95	false, false, false),
	96	};
	97
	98	static const struct lttng_kernel_tracepoint_class tp_class = {
	99	.nr_fields = ARRAY_SIZE(event_fields),
	100	.fields = event_fields,
	101	};
437d5aa5	102
f17701fb MD	103	/*
	104	* Create event description
	105	*/
	106	static
a67ba386	107	int lttng_create_kprobe_event(const char name, struct lttng_kernel_event_recorder event_recorder)
f17701fb	108	{
437d5aa5	109	struct lttng_kernel_event_desc *desc;
f17701fb MD	110	int ret;
f17701fb MD	111
437d5aa5	112	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
d3dbe23c	113	if (!desc)
f17701fb	114	return -ENOMEM;
6c8c025b	115	desc->tp_class = &tp_class;
437d5aa5 MD	116	desc->event_name = kstrdup(name, GFP_KERNEL);
437d5aa5 MD	117	if (!desc->event_name) {
f17701fb MD	118	ret = -ENOMEM;
	119	goto error_str;
	120	}
dc7f600a	121	desc->owner = THIS_MODULE;
a67ba386	122	event_recorder->priv->parent.desc = desc;
f17701fb MD	123
	124	return 0;
	125
	126	error_str:
d3dbe23c	127	kfree(desc);
f17701fb MD	128	return ret;
	129	}
	130
2b16f0c9 FD	131	/*
	132	* Create event_notifier description
	133	*/
	134	static
a67ba386	135	int lttng_create_kprobe_event_notifier(const char name, struct lttng_kernel_event_notifier event_notifier)
2b16f0c9	136	{
437d5aa5	137	struct lttng_kernel_event_desc *desc;
2b16f0c9 FD	138	int ret;
2b16f0c9 FD	139
437d5aa5	140	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
2b16f0c9 FD	141	if (!desc)
2b16f0c9 FD	142	return -ENOMEM;
6c8c025b	143	desc->tp_class = &tp_class;
437d5aa5 MD	144	desc->event_name = kstrdup(name, GFP_KERNEL);
437d5aa5 MD	145	if (!desc->event_name) {
2b16f0c9 FD	146	ret = -ENOMEM;
	147	goto error_str;
	148	}
2b16f0c9	149	desc->owner = THIS_MODULE;
a67ba386	150	event_notifier->priv->parent.desc = desc;
2b16f0c9 FD	151
	152	return 0;
	153
	154	error_str:
	155	kfree(desc);
	156	return ret;
	157	}
	158
8bf17deb FD	159	static
8bf17deb FD	160	int _lttng_kprobes_register(const char *symbol_name,
f17701fb MD	161	uint64_t offset,
f17701fb MD	162	uint64_t addr,
8bf17deb FD	163	struct lttng_kprobe *lttng_kp,
8bf17deb FD	164	kprobe_pre_handler_t pre_handler)
f17701fb MD	165	{
	166	int ret;
	167
c37f2a9b MD	168	/* Kprobes expects a NULL symbol name if unused */
	169	if (symbol_name[0] == '\0')
	170	symbol_name = NULL;
	171
8bf17deb FD	172	memset(&lttng_kp->kp, 0, sizeof(lttng_kp->kp));
	173	lttng_kp->kp.pre_handler = pre_handler;
	174
c37f2a9b	175	if (symbol_name) {
8bf17deb	176	lttng_kp->symbol_name =
606828e4	177	kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char),
c37f2a9b	178	GFP_KERNEL);
8bf17deb	179	if (!lttng_kp->symbol_name) {
c37f2a9b MD	180	ret = -ENOMEM;
	181	goto name_error;
	182	}
8bf17deb	183	memcpy(lttng_kp->symbol_name, symbol_name,
606828e4	184	LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char));
8bf17deb	185	lttng_kp->kp.symbol_name = lttng_kp->symbol_name;
f17701fb	186	}
8bf17deb FD	187
	188	lttng_kp->kp.offset = offset;
	189	lttng_kp->kp.addr = (void *) (unsigned long) addr;
16a9a591 MD	190
16a9a591 MD	191	/*
196bfc6a	192	* Ensure the memory we just allocated don't notify page faults.
16a9a591 MD	193	* Well.. kprobes itself puts the page fault handler on the blacklist,
	194	* but we can never be too careful.
	195	*/
263b6c88	196	wrapper_vmalloc_sync_mappings();
16a9a591	197
8bf17deb	198	ret = register_kprobe(&lttng_kp->kp);
f17701fb MD	199	if (ret)
f17701fb MD	200	goto register_error;
8bf17deb	201
f17701fb MD	202	return 0;
	203
	204	register_error:
8bf17deb	205	kfree(lttng_kp->symbol_name);
f17701fb	206	name_error:
8bf17deb FD	207	return ret;
	208	}
	209
	210	int lttng_kprobes_register_event(const char *name,
	211	const char *symbol_name,
	212	uint64_t offset,
	213	uint64_t addr,
a67ba386	214	struct lttng_kernel_event_recorder *event_recorder)
8bf17deb FD	215	{
	216	int ret;
	217
a67ba386	218	ret = lttng_create_kprobe_event(name, event_recorder);
8bf17deb FD	219	if (ret)
	220	goto error;
	221
	222	ret = _lttng_kprobes_register(symbol_name, offset, addr,
a67ba386	223	&event_recorder->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre);
8bf17deb FD	224	if (ret)
	225	goto register_error;
	226
	227	return 0;
	228
	229	register_error:
a67ba386 MD	230	kfree(event_recorder->priv->parent.desc->event_name);
a67ba386 MD	231	kfree(event_recorder->priv->parent.desc);
f17701fb MD	232	error:
	233	return ret;
	234	}
8bf17deb	235	EXPORT_SYMBOL_GPL(lttng_kprobes_register_event);
f17701fb	236
2b16f0c9 FD	237	int lttng_kprobes_register_event_notifier(const char *symbol_name,
	238	uint64_t offset,
	239	uint64_t addr,
a67ba386	240	struct lttng_kernel_event_notifier *event_notifier)
2b16f0c9 FD	241	{
	242	int ret;
	243	ret = lttng_create_kprobe_event_notifier(symbol_name, event_notifier);
	244	if (ret)
	245	goto error;
	246
	247	ret = _lttng_kprobes_register(symbol_name, offset, addr,
e2d5dbc7	248	&event_notifier->priv->parent.u.kprobe, lttng_kprobes_event_handler_pre);
2b16f0c9 FD	249	if (ret)
	250	goto register_error;
	251
	252	return 0;
	253
	254	register_error:
a67ba386 MD	255	kfree(event_notifier->priv->parent.desc->event_name);
a67ba386 MD	256	kfree(event_notifier->priv->parent.desc);
2b16f0c9 FD	257	error:
	258	return ret;
	259	}
	260	EXPORT_SYMBOL_GPL(lttng_kprobes_register_event_notifier);
	261
a67ba386	262	void lttng_kprobes_unregister_event(struct lttng_kernel_event_recorder *event_recorder)
f17701fb	263	{
a67ba386	264	unregister_kprobe(&event_recorder->priv->parent.u.kprobe.kp);
edeb3137	265	}
8bf17deb	266	EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event);
edeb3137	267
a67ba386	268	void lttng_kprobes_unregister_event_notifier(struct lttng_kernel_event_notifier *event_notifier)
2b16f0c9	269	{
a67ba386	270	unregister_kprobe(&event_notifier->priv->parent.u.kprobe.kp);
2b16f0c9 FD	271	}
	272	EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event_notifier);
	273
a67ba386	274	void lttng_kprobes_destroy_event_private(struct lttng_kernel_event_recorder *event_recorder)
edeb3137	275	{
a67ba386	276	kfree(event_recorder->priv->parent.u.kprobe.symbol_name);
a67ba386 MD	277	kfree(event_recorder->priv->parent.desc->event_name);
a67ba386 MD	278	kfree(event_recorder->priv->parent.desc);
f17701fb	279	}
8bf17deb	280	EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private);
d6d808f3	281
a67ba386	282	void lttng_kprobes_destroy_event_notifier_private(struct lttng_kernel_event_notifier *event_notifier)
2b16f0c9	283	{
a67ba386 MD	284	kfree(event_notifier->priv->parent.u.kprobe.symbol_name);
	285	kfree(event_notifier->priv->parent.desc->event_name);
	286	kfree(event_notifier->priv->parent.desc);
2b16f0c9 FD	287	}
	288	EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_notifier_private);
	289
d6d808f3	290	MODULE_LICENSE("GPL and additional rights");
1c124020 MJ	291	MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
1c124020 MJ	292	MODULE_DESCRIPTION("LTTng kprobes probes");
13ab8b0a MD	293	MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
	294	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
	295	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
	296	LTTNG_MODULES_EXTRAVERSION);