[lttng-modules.git] / lttng-syscalls.c

/*
 * lttng-syscalls.c
 *
 * LTTng syscall probes.
 *
 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/compat.h>
#include <asm/ptrace.h>
#include <asm/syscall.h>

#include "lttng-events.h"

#ifndef CONFIG_COMPAT
static inline int is_compat_task(void)
{
	return 0;
}
#endif

static
void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);

/*
 * Take care of NOARGS not supported by mainline.
 */
#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
#define DEFINE_EVENT_NOARGS(template, name)
#define TRACE_EVENT_NOARGS(name, struct, assign, print)

/*
 * Create LTTng tracepoint probes.
 */
#define LTTNG_PACKAGE_BUILD
#define CREATE_TRACE_POINTS
#define TP_MODULE_OVERRIDE
#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers

#define PARAMS(args...)	args

/* Hijack probe callback for system calls */
#undef TP_PROBE_CB
#define TP_PROBE_CB(_template)		&syscall_entry_probe
#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk)	\
	TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\
		PARAMS(_struct), PARAMS(_assign), PARAMS(_printk))
#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk)	\
	DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\
		PARAMS(_printk))
#define SC_DEFINE_EVENT_NOARGS(_template, _name)			\
	DEFINE_EVENT_NOARGS(_template, _name)
#undef TRACE_SYSTEM
#define TRACE_SYSTEM syscalls_integers
#include "instrumentation/syscalls/headers/syscalls_integers.h"
#undef TRACE_SYSTEM
#define TRACE_SYSTEM syscalls_pointers
#include "instrumentation/syscalls/headers/syscalls_pointers.h"
#undef TRACE_SYSTEM
#undef SC_TRACE_EVENT
#undef SC_DECLARE_EVENT_CLASS_NOARGS
#undef SC_DEFINE_EVENT_NOARGS

#define TRACE_SYSTEM syscalls_unknown
#include "instrumentation/syscalls/headers/syscalls_unknown.h"
#undef TRACE_SYSTEM

/* For compat syscalls */
#undef _TRACE_SYSCALLS_integers_H
#undef _TRACE_SYSCALLS_pointers_H

/* Hijack probe callback for system calls */
#undef TP_PROBE_CB
#define TP_PROBE_CB(_template)		&syscall_entry_probe
#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk)	\
	TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args),	\
		PARAMS(_struct), PARAMS(_assign),			\
		PARAMS(_printk))
#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
	DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct),	\
		PARAMS(_assign), PARAMS(_printk))
#define SC_DEFINE_EVENT_NOARGS(_template, _name)			\
	DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name)
#define TRACE_SYSTEM compat_syscalls_integers
#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
#undef TRACE_SYSTEM
#define TRACE_SYSTEM compat_syscalls_pointers
#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
#undef TRACE_SYSTEM
#undef SC_TRACE_EVENT
#undef SC_DECLARE_EVENT_CLASS_NOARGS
#undef SC_DEFINE_EVENT_NOARGS
#undef TP_PROBE_CB

#undef TP_MODULE_OVERRIDE
#undef LTTNG_PACKAGE_BUILD
#undef CREATE_TRACE_POINTS

struct trace_syscall_entry {
	void *func;
	const struct lttng_event_desc *desc;
	const struct lttng_event_field *fields;
	unsigned int nrargs;
};

#define CREATE_SYSCALL_TABLE

#undef TRACE_SYSCALL_TABLE
#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)	\
	[ _nr ] = {						\
		.func = __event_probe__##_template,		\
		.nrargs = (_nrargs),				\
		.fields = __event_fields___##_template,		\
		.desc = &__event_desc___##_name,		\
	},

static const struct trace_syscall_entry sc_table[] = {
#include "instrumentation/syscalls/headers/syscalls_integers.h"
#include "instrumentation/syscalls/headers/syscalls_pointers.h"
};

#undef TRACE_SYSCALL_TABLE
#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)	\
	[ _nr ] = {						\
		.func = __event_probe__##compat_##_template,	\
		.nrargs = (_nrargs),				\
		.fields = __event_fields___##compat_##_template,\
		.desc = &__event_desc___##compat_##_name,	\
	},

/* Create compatibility syscall table */
const struct trace_syscall_entry compat_sc_table[] = {
#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
};

#undef CREATE_SYSCALL_TABLE

static void syscall_entry_unknown(struct lttng_event *event,
	struct pt_regs *regs, unsigned int id)
{
	unsigned long args[UNKNOWN_SYSCALL_NRARGS];

	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
	if (unlikely(is_compat_task()))
		__event_probe__compat_sys_unknown(event, id, args);
	else
		__event_probe__sys_unknown(event, id, args);
}

void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
{
	struct lttng_channel *chan = __data;
	struct lttng_event *event, *unknown_event;
	const struct trace_syscall_entry *table, *entry;
	size_t table_len;

	if (unlikely(is_compat_task())) {
		table = compat_sc_table;
		table_len = ARRAY_SIZE(compat_sc_table);
		unknown_event = chan->sc_compat_unknown;
	} else {
		table = sc_table;
		table_len = ARRAY_SIZE(sc_table);
		unknown_event = chan->sc_unknown;
	}
	if (unlikely(id >= table_len)) {
		syscall_entry_unknown(unknown_event, regs, id);
		return;
	}
	if (unlikely(is_compat_task()))
		event = chan->compat_sc_table[id];
	else
		event = chan->sc_table[id];
	if (unlikely(!event)) {
		syscall_entry_unknown(unknown_event, regs, id);
		return;
	}
	entry = &table[id];
	WARN_ON_ONCE(!entry);

	switch (entry->nrargs) {
	case 0:
	{
		void (*fptr)(void *__data) = entry->func;

		fptr(event);
		break;
	}
	case 1:
	{
		void (*fptr)(void *__data, unsigned long arg0) = entry->func;
		unsigned long args[1];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0]);
		break;
	}
	case 2:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1) = entry->func;
		unsigned long args[2];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1]);
		break;
	}
	case 3:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2) = entry->func;
		unsigned long args[3];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2]);
		break;
	}
	case 4:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3) = entry->func;
		unsigned long args[4];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2], args[3]);
		break;
	}
	case 5:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3,
			unsigned long arg4) = entry->func;
		unsigned long args[5];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2], args[3], args[4]);
		break;
	}
	case 6:
	{
		void (*fptr)(void *__data,
			unsigned long arg0,
			unsigned long arg1,
			unsigned long arg2,
			unsigned long arg3,
			unsigned long arg4,
			unsigned long arg5) = entry->func;
		unsigned long args[6];

		syscall_get_arguments(current, regs, 0, entry->nrargs, args);
		fptr(event, args[0], args[1], args[2],
			args[3], args[4], args[5]);
		break;
	}
	default:
		break;
	}
}

/* noinline to diminish caller stack size */
static
int fill_table(const struct trace_syscall_entry *table, size_t table_len,
	struct lttng_event **chan_table, struct lttng_channel *chan, void *filter)
{
	const struct lttng_event_desc *desc;
	unsigned int i;

	/* Allocate events for each syscall, insert into table */
	for (i = 0; i < table_len; i++) {
		struct lttng_kernel_event ev;
		desc = table[i].desc;

		if (!desc) {
			/* Unknown syscall */
			continue;
		}
		/*
		 * Skip those already populated by previous failed
		 * register for this channel.
		 */
		if (chan_table[i])
			continue;
		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
		ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan_table[i] = lttng_event_create(chan, &ev, filter,
						desc);
		if (!chan_table[i]) {
			/*
			 * If something goes wrong in event registration
			 * after the first one, we have no choice but to
			 * leave the previous events in there, until
			 * deleted by session teardown.
			 */
			return -EINVAL;
		}
	}
	return 0;
}

int lttng_syscalls_register(struct lttng_channel *chan, void *filter)
{
	struct lttng_kernel_event ev;
	int ret;

	wrapper_vmalloc_sync_all();

	if (!chan->sc_table) {
		/* create syscall table mapping syscall to events */
		chan->sc_table = kzalloc(sizeof(struct lttng_event *)
					* ARRAY_SIZE(sc_table), GFP_KERNEL);
		if (!chan->sc_table)
			return -ENOMEM;
	}

#ifdef CONFIG_COMPAT
	if (!chan->compat_sc_table) {
		/* create syscall table mapping compat syscall to events */
		chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *)
					* ARRAY_SIZE(compat_sc_table), GFP_KERNEL);
		if (!chan->compat_sc_table)
			return -ENOMEM;
	}
#endif
	if (!chan->sc_unknown) {
		const struct lttng_event_desc *desc =
			&__event_desc___sys_unknown;

		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
		ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_unknown = lttng_event_create(chan, &ev, filter,
						    desc);
		if (!chan->sc_unknown) {
			return -EINVAL;
		}
	}

	if (!chan->sc_compat_unknown) {
		const struct lttng_event_desc *desc =
			&__event_desc___compat_sys_unknown;

		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
		ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_compat_unknown = lttng_event_create(chan, &ev, filter,
							   desc);
		if (!chan->sc_compat_unknown) {
			return -EINVAL;
		}
	}

	if (!chan->sc_exit) {
		const struct lttng_event_desc *desc =
			&__event_desc___exit_syscall;

		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
		ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_exit = lttng_event_create(chan, &ev, filter,
						 desc);
		if (!chan->sc_exit) {
			return -EINVAL;
		}
	}

	ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
			chan->sc_table, chan, filter);
	if (ret)
		return ret;
#ifdef CONFIG_COMPAT
	ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
			chan->compat_sc_table, chan, filter);
	if (ret)
		return ret;
#endif
	ret = tracepoint_probe_register("sys_enter",
			(void *) syscall_entry_probe, chan);
	if (ret)
		return ret;
	/*
	 * We change the name of sys_exit tracepoint due to namespace
	 * conflict with sys_exit syscall entry.
	 */
	ret = tracepoint_probe_register("sys_exit",
			(void *) __event_probe__exit_syscall,
			chan->sc_exit);
	if (ret) {
		WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
			(void *) syscall_entry_probe, chan));
	}
	return ret;
}

/*
 * Only called at session destruction.
 */
int lttng_syscalls_unregister(struct lttng_channel *chan)
{
	int ret;

	if (!chan->sc_table)
		return 0;
	ret = tracepoint_probe_unregister("sys_exit",
			(void *) __event_probe__exit_syscall,
			chan->sc_exit);
	if (ret)
		return ret;
	ret = tracepoint_probe_unregister("sys_enter",
			(void *) syscall_entry_probe, chan);
	if (ret)
		return ret;
	/* lttng_event destroy will be performed by lttng_session_destroy() */
	kfree(chan->sc_table);
#ifdef CONFIG_COMPAT
	kfree(chan->compat_sc_table);
#endif
	return 0;
}
Commit	Line	Data
259b6cb3 MD	1	/*
	2	* lttng-syscalls.c
	3	*
2faf7d1b	4	* LTTng syscall probes.
259b6cb3	5	*
886d51a3 MD	6	* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
259b6cb3 MD	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/slab.h>
6333ace3	25	#include <linux/compat.h>
259b6cb3 MD	26	#include <asm/ptrace.h>
	27	#include <asm/syscall.h>
	28
a90917c3	29	#include "lttng-events.h"
259b6cb3	30
6333ace3 MD	31	#ifndef CONFIG_COMPAT
	32	static inline int is_compat_task(void)
	33	{
	34	return 0;
	35	}
	36	#endif
	37
a93244f8	38	static
2faf7d1b	39	void syscall_entry_probe(void __data, struct pt_regs regs, long id);
259b6cb3	40
f7bdf4db MD	41	/*
	42	* Take care of NOARGS not supported by mainline.
	43	*/
	44	#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
	45	#define DEFINE_EVENT_NOARGS(template, name)
	46	#define TRACE_EVENT_NOARGS(name, struct, assign, print)
	47
259b6cb3 MD	48	/*
	49	* Create LTTng tracepoint probes.
	50	*/
	51	#define LTTNG_PACKAGE_BUILD
	52	#define CREATE_TRACE_POINTS
2f804c0a MD	53	#define TP_MODULE_OVERRIDE
2f804c0a MD	54	#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
259b6cb3	55
a93244f8 MD	56	#define PARAMS(args...) args
a93244f8 MD	57
259b6cb3	58	/* Hijack probe callback for system calls */
a93244f8	59	#undef TP_PROBE_CB
259b6cb3	60	#define TP_PROBE_CB(_template) &syscall_entry_probe
a93244f8 MD	61	#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
	62	TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\
	63	PARAMS(_struct), PARAMS(_assign), PARAMS(_printk))
	64	#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
	65	DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\
	66	PARAMS(_printk))
	67	#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
	68	DEFINE_EVENT_NOARGS(_template, _name)
	69	#undef TRACE_SYSTEM
	70	#define TRACE_SYSTEM syscalls_integers
177b3692	71	#include "instrumentation/syscalls/headers/syscalls_integers.h"
a93244f8 MD	72	#undef TRACE_SYSTEM
a93244f8 MD	73	#define TRACE_SYSTEM syscalls_pointers
177b3692	74	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
a93244f8 MD	75	#undef TRACE_SYSTEM
	76	#undef SC_TRACE_EVENT
	77	#undef SC_DECLARE_EVENT_CLASS_NOARGS
	78	#undef SC_DEFINE_EVENT_NOARGS
2f804c0a	79
a93244f8	80	#define TRACE_SYSTEM syscalls_unknown
63728b02	81	#include "instrumentation/syscalls/headers/syscalls_unknown.h"
a93244f8 MD	82	#undef TRACE_SYSTEM
	83
	84	/* For compat syscalls */
	85	#undef _TRACE_SYSCALLS_integers_H
	86	#undef _TRACE_SYSCALLS_pointers_H
	87
	88	/* Hijack probe callback for system calls */
	89	#undef TP_PROBE_CB
	90	#define TP_PROBE_CB(_template) &syscall_entry_probe
	91	#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
	92	TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args), \
	93	PARAMS(_struct), PARAMS(_assign), \
	94	PARAMS(_printk))
	95	#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
	96	DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct), \
	97	PARAMS(_assign), PARAMS(_printk))
	98	#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
	99	DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name)
	100	#define TRACE_SYSTEM compat_syscalls_integers
	101	#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
	102	#undef TRACE_SYSTEM
	103	#define TRACE_SYSTEM compat_syscalls_pointers
	104	#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
	105	#undef TRACE_SYSTEM
	106	#undef SC_TRACE_EVENT
	107	#undef SC_DECLARE_EVENT_CLASS_NOARGS
	108	#undef SC_DEFINE_EVENT_NOARGS
	109	#undef TP_PROBE_CB
259b6cb3 MD	110
259b6cb3 MD	111	#undef TP_MODULE_OVERRIDE
259b6cb3 MD	112	#undef LTTNG_PACKAGE_BUILD
	113	#undef CREATE_TRACE_POINTS
	114
a93244f8 MD	115	struct trace_syscall_entry {
	116	void *func;
	117	const struct lttng_event_desc *desc;
	118	const struct lttng_event_field *fields;
	119	unsigned int nrargs;
	120	};
	121
	122	#define CREATE_SYSCALL_TABLE
	123
259b6cb3	124	#undef TRACE_SYSCALL_TABLE
f7bdf4db	125	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
259b6cb3	126	[ _nr ] = { \
f7bdf4db	127	.func = __event_probe__##_template, \
259b6cb3	128	.nrargs = (_nrargs), \
f7bdf4db MD	129	.fields = __event_fields___##_template, \
f7bdf4db MD	130	.desc = &__event_desc___##_name, \
259b6cb3 MD	131	},
259b6cb3 MD	132
49c50022	133	static const struct trace_syscall_entry sc_table[] = {
177b3692 MD	134	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	135	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
259b6cb3 MD	136	};
259b6cb3 MD	137
a93244f8 MD	138	#undef TRACE_SYSCALL_TABLE
	139	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
	140	[ _nr ] = { \
	141	.func = __event_probe__##compat_##_template, \
	142	.nrargs = (_nrargs), \
	143	.fields = __event_fields___##compat_##_template,\
	144	.desc = &__event_desc___##compat_##_name, \
	145	},
	146
	147	/* Create compatibility syscall table */
	148	const struct trace_syscall_entry compat_sc_table[] = {
	149	#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
	150	#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
	151	};
259b6cb3	152
a93244f8	153	#undef CREATE_SYSCALL_TABLE
2faf7d1b	154
a90917c3	155	static void syscall_entry_unknown(struct lttng_event *event,
f405cfce MD	156	struct pt_regs *regs, unsigned int id)
	157	{
	158	unsigned long args[UNKNOWN_SYSCALL_NRARGS];
f405cfce	159
f405cfce	160	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
a93244f8 MD	161	if (unlikely(is_compat_task()))
	162	__event_probe__compat_sys_unknown(event, id, args);
	163	else
	164	__event_probe__sys_unknown(event, id, args);
f405cfce MD	165	}
f405cfce MD	166
2faf7d1b	167	void syscall_entry_probe(void __data, struct pt_regs regs, long id)
259b6cb3	168	{
a90917c3 MD	169	struct lttng_channel *chan = __data;
a90917c3 MD	170	struct lttng_event event, unknown_event;
49c50022 MD	171	const struct trace_syscall_entry table, entry;
49c50022 MD	172	size_t table_len;
259b6cb3	173
b76dc1a0	174	if (unlikely(is_compat_task())) {
49c50022	175	table = compat_sc_table;
a93244f8	176	table_len = ARRAY_SIZE(compat_sc_table);
49c50022 MD	177	unknown_event = chan->sc_compat_unknown;
	178	} else {
	179	table = sc_table;
	180	table_len = ARRAY_SIZE(sc_table);
	181	unknown_event = chan->sc_unknown;
b76dc1a0	182	}
49c50022 MD	183	if (unlikely(id >= table_len)) {
49c50022 MD	184	syscall_entry_unknown(unknown_event, regs, id);
259b6cb3	185	return;
f405cfce	186	}
49c50022 MD	187	if (unlikely(is_compat_task()))
	188	event = chan->compat_sc_table[id];
	189	else
	190	event = chan->sc_table[id];
f405cfce	191	if (unlikely(!event)) {
49c50022	192	syscall_entry_unknown(unknown_event, regs, id);
f405cfce MD	193	return;
f405cfce MD	194	}
49c50022	195	entry = &table[id];
f405cfce	196	WARN_ON_ONCE(!entry);
259b6cb3 MD	197
	198	switch (entry->nrargs) {
	199	case 0:
	200	{
	201	void (fptr)(void __data) = entry->func;
	202
	203	fptr(event);
	204	break;
	205	}
	206	case 1:
	207	{
	208	void (fptr)(void __data, unsigned long arg0) = entry->func;
	209	unsigned long args[1];
	210
	211	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	212	fptr(event, args[0]);
	213	break;
	214	}
	215	case 2:
	216	{
	217	void (fptr)(void __data,
	218	unsigned long arg0,
	219	unsigned long arg1) = entry->func;
	220	unsigned long args[2];
	221
	222	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	223	fptr(event, args[0], args[1]);
	224	break;
	225	}
	226	case 3:
	227	{
	228	void (fptr)(void __data,
	229	unsigned long arg0,
	230	unsigned long arg1,
	231	unsigned long arg2) = entry->func;
	232	unsigned long args[3];
	233
	234	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	235	fptr(event, args[0], args[1], args[2]);
	236	break;
	237	}
	238	case 4:
	239	{
	240	void (fptr)(void __data,
	241	unsigned long arg0,
	242	unsigned long arg1,
	243	unsigned long arg2,
	244	unsigned long arg3) = entry->func;
	245	unsigned long args[4];
	246
	247	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	248	fptr(event, args[0], args[1], args[2], args[3]);
	249	break;
	250	}
	251	case 5:
	252	{
	253	void (fptr)(void __data,
	254	unsigned long arg0,
	255	unsigned long arg1,
	256	unsigned long arg2,
	257	unsigned long arg3,
	258	unsigned long arg4) = entry->func;
	259	unsigned long args[5];
	260
261	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
262	fptr(event, args[0], args[1], args[2], args[3], args[4]);
263	break;
264	}
265	case 6:
266	{
267	void (fptr)(void __data,
268	unsigned long arg0,
269	unsigned long arg1,
270	unsigned long arg2,
271	unsigned long arg3,
272	unsigned long arg4,
273	unsigned long arg5) = entry->func;
274	unsigned long args[6];
275
276	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
277	fptr(event, args[0], args[1], args[2],
278	args[3], args[4], args[5]);
279	break;
280	}
281	default:
282	break;
283	}
284	}
285
2a0c4816	286	/* noinline to diminish caller stack size */
49c50022 MD	287	static
49c50022 MD	288	int fill_table(const struct trace_syscall_entry *table, size_t table_len,
a90917c3	289	struct lttng_event *chan_table, struct lttng_channel chan, void *filter)
259b6cb3	290	{
2a0c4816	291	const struct lttng_event_desc *desc;
259b6cb3	292	unsigned int i;
49c50022 MD	293
	294	/* Allocate events for each syscall, insert into table */
	295	for (i = 0; i < table_len; i++) {
	296	struct lttng_kernel_event ev;
2a0c4816	297	desc = table[i].desc;
49c50022 MD	298
	299	if (!desc) {
	300	/* Unknown syscall */
	301	continue;
	302	}
	303	/*
	304	* Skip those already populated by previous failed
	305	* register for this channel.
	306	*/
	307	if (chan_table[i])
	308	continue;
	309	memset(&ev, 0, sizeof(ev));
f8695253 MD	310	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	311	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
49c50022	312	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	313	chan_table[i] = lttng_event_create(chan, &ev, filter,
49c50022 MD	314	desc);
	315	if (!chan_table[i]) {
	316	/*
	317	* If something goes wrong in event registration
	318	* after the first one, we have no choice but to
	319	* leave the previous events in there, until
	320	* deleted by session teardown.
	321	*/
	322	return -EINVAL;
	323	}
	324	}
	325	return 0;
	326	}
	327
a90917c3	328	int lttng_syscalls_register(struct lttng_channel chan, void filter)
49c50022	329	{
2a0c4816	330	struct lttng_kernel_event ev;
259b6cb3 MD	331	int ret;
	332
	333	wrapper_vmalloc_sync_all();
259b6cb3 MD	334
	335	if (!chan->sc_table) {
	336	/* create syscall table mapping syscall to events */
a90917c3	337	chan->sc_table = kzalloc(sizeof(struct lttng_event *)
259b6cb3 MD	338	* ARRAY_SIZE(sc_table), GFP_KERNEL);
	339	if (!chan->sc_table)
	340	return -ENOMEM;
	341	}
	342
49c50022 MD	343	#ifdef CONFIG_COMPAT
	344	if (!chan->compat_sc_table) {
	345	/* create syscall table mapping compat syscall to events */
a90917c3	346	chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *)
a93244f8	347	* ARRAY_SIZE(compat_sc_table), GFP_KERNEL);
49c50022 MD	348	if (!chan->compat_sc_table)
	349	return -ENOMEM;
	350	}
	351	#endif
f405cfce	352	if (!chan->sc_unknown) {
f405cfce MD	353	const struct lttng_event_desc *desc =
f405cfce MD	354	&__event_desc___sys_unknown;
2f804c0a	355
f405cfce	356	memset(&ev, 0, sizeof(ev));
f8695253 MD	357	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	358	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
f405cfce	359	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	360	chan->sc_unknown = lttng_event_create(chan, &ev, filter,
f405cfce MD	361	desc);
	362	if (!chan->sc_unknown) {
	363	return -EINVAL;
	364	}
	365	}
	366
b76dc1a0	367	if (!chan->sc_compat_unknown) {
b76dc1a0 MD	368	const struct lttng_event_desc *desc =
	369	&__event_desc___compat_sys_unknown;
	370
	371	memset(&ev, 0, sizeof(ev));
f8695253 MD	372	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	373	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
b76dc1a0	374	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	375	chan->sc_compat_unknown = lttng_event_create(chan, &ev, filter,
b76dc1a0 MD	376	desc);
	377	if (!chan->sc_compat_unknown) {
	378	return -EINVAL;
	379	}
	380	}
	381
2f804c0a	382	if (!chan->sc_exit) {
2f804c0a MD	383	const struct lttng_event_desc *desc =
	384	&__event_desc___exit_syscall;
	385
	386	memset(&ev, 0, sizeof(ev));
f8695253 MD	387	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	388	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
2f804c0a	389	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	390	chan->sc_exit = lttng_event_create(chan, &ev, filter,
2f804c0a MD	391	desc);
	392	if (!chan->sc_exit) {
	393	return -EINVAL;
	394	}
	395	}
	396
49c50022 MD	397	ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
	398	chan->sc_table, chan, filter);
	399	if (ret)
	400	return ret;
	401	#ifdef CONFIG_COMPAT
a93244f8	402	ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
49c50022 MD	403	chan->compat_sc_table, chan, filter);
	404	if (ret)
	405	return ret;
	406	#endif
259b6cb3 MD	407	ret = tracepoint_probe_register("sys_enter",
259b6cb3 MD	408	(void *) syscall_entry_probe, chan);
63728b02 MD	409	if (ret)
	410	return ret;
	411	/*
	412	* We change the name of sys_exit tracepoint due to namespace
	413	* conflict with sys_exit syscall entry.
	414	*/
	415	ret = tracepoint_probe_register("sys_exit",
2c01ec07	416	(void *) __event_probe__exit_syscall,
2f804c0a	417	chan->sc_exit);
63728b02 MD	418	if (ret) {
	419	WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
	420	(void *) syscall_entry_probe, chan));
	421	}
259b6cb3 MD	422	return ret;
	423	}
	424
	425	/*
	426	* Only called at session destruction.
	427	*/
a90917c3	428	int lttng_syscalls_unregister(struct lttng_channel *chan)
259b6cb3 MD	429	{
	430	int ret;
	431
	432	if (!chan->sc_table)
	433	return 0;
63728b02	434	ret = tracepoint_probe_unregister("sys_exit",
2c01ec07	435	(void *) __event_probe__exit_syscall,
2f804c0a	436	chan->sc_exit);
63728b02 MD	437	if (ret)
63728b02 MD	438	return ret;
259b6cb3 MD	439	ret = tracepoint_probe_unregister("sys_enter",
	440	(void *) syscall_entry_probe, chan);
	441	if (ret)
	442	return ret;
a90917c3	443	/* lttng_event destroy will be performed by lttng_session_destroy() */
259b6cb3	444	kfree(chan->sc_table);
49c50022 MD	445	#ifdef CONFIG_COMPAT
	446	kfree(chan->compat_sc_table);
	447	#endif
259b6cb3 MD	448	return 0;
259b6cb3 MD	449	}