[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
# ifndef is_compat_task
#  define is_compat_task()	(0)
# endif
#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	31	#ifndef CONFIG_COMPAT
bfa949bf MD	32	# ifndef is_compat_task
	33	# define is_compat_task() (0)
	34	# endif
6333ace3 MD	35	#endif
6333ace3 MD	36
a93244f8	37	static
2faf7d1b	38	void syscall_entry_probe(void __data, struct pt_regs regs, long id);
259b6cb3	39
f7bdf4db MD	40	/*
	41	* Take care of NOARGS not supported by mainline.
	42	*/
	43	#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
	44	#define DEFINE_EVENT_NOARGS(template, name)
	45	#define TRACE_EVENT_NOARGS(name, struct, assign, print)
	46
259b6cb3 MD	47	/*
	48	* Create LTTng tracepoint probes.
	49	*/
	50	#define LTTNG_PACKAGE_BUILD
	51	#define CREATE_TRACE_POINTS
2f804c0a MD	52	#define TP_MODULE_OVERRIDE
2f804c0a MD	53	#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
259b6cb3	54
a93244f8 MD	55	#define PARAMS(args...) args
a93244f8 MD	56
259b6cb3	57	/* Hijack probe callback for system calls */
a93244f8	58	#undef TP_PROBE_CB
259b6cb3	59	#define TP_PROBE_CB(_template) &syscall_entry_probe
a93244f8 MD	60	#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
	61	TRACE_EVENT(_name, PARAMS(_proto), PARAMS(_args),\
	62	PARAMS(_struct), PARAMS(_assign), PARAMS(_printk))
	63	#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
	64	DECLARE_EVENT_CLASS_NOARGS(_name, PARAMS(_struct), PARAMS(_assign),\
	65	PARAMS(_printk))
	66	#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
	67	DEFINE_EVENT_NOARGS(_template, _name)
	68	#undef TRACE_SYSTEM
	69	#define TRACE_SYSTEM syscalls_integers
177b3692	70	#include "instrumentation/syscalls/headers/syscalls_integers.h"
a93244f8 MD	71	#undef TRACE_SYSTEM
a93244f8 MD	72	#define TRACE_SYSTEM syscalls_pointers
177b3692	73	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
a93244f8 MD	74	#undef TRACE_SYSTEM
	75	#undef SC_TRACE_EVENT
	76	#undef SC_DECLARE_EVENT_CLASS_NOARGS
	77	#undef SC_DEFINE_EVENT_NOARGS
2f804c0a	78
a93244f8	79	#define TRACE_SYSTEM syscalls_unknown
63728b02	80	#include "instrumentation/syscalls/headers/syscalls_unknown.h"
a93244f8 MD	81	#undef TRACE_SYSTEM
	82
	83	/* For compat syscalls */
	84	#undef _TRACE_SYSCALLS_integers_H
	85	#undef _TRACE_SYSCALLS_pointers_H
	86
	87	/* Hijack probe callback for system calls */
	88	#undef TP_PROBE_CB
	89	#define TP_PROBE_CB(_template) &syscall_entry_probe
	90	#define SC_TRACE_EVENT(_name, _proto, _args, _struct, _assign, _printk) \
	91	TRACE_EVENT(compat_##_name, PARAMS(_proto), PARAMS(_args), \
	92	PARAMS(_struct), PARAMS(_assign), \
	93	PARAMS(_printk))
	94	#define SC_DECLARE_EVENT_CLASS_NOARGS(_name, _struct, _assign, _printk) \
	95	DECLARE_EVENT_CLASS_NOARGS(compat_##_name, PARAMS(_struct), \
	96	PARAMS(_assign), PARAMS(_printk))
	97	#define SC_DEFINE_EVENT_NOARGS(_template, _name) \
	98	DEFINE_EVENT_NOARGS(compat_##_template, compat_##_name)
	99	#define TRACE_SYSTEM compat_syscalls_integers
	100	#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
	101	#undef TRACE_SYSTEM
	102	#define TRACE_SYSTEM compat_syscalls_pointers
	103	#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
	104	#undef TRACE_SYSTEM
	105	#undef SC_TRACE_EVENT
	106	#undef SC_DECLARE_EVENT_CLASS_NOARGS
	107	#undef SC_DEFINE_EVENT_NOARGS
	108	#undef TP_PROBE_CB
259b6cb3 MD	109
259b6cb3 MD	110	#undef TP_MODULE_OVERRIDE
259b6cb3 MD	111	#undef LTTNG_PACKAGE_BUILD
	112	#undef CREATE_TRACE_POINTS
	113
a93244f8 MD	114	struct trace_syscall_entry {
	115	void *func;
	116	const struct lttng_event_desc *desc;
	117	const struct lttng_event_field *fields;
	118	unsigned int nrargs;
	119	};
	120
	121	#define CREATE_SYSCALL_TABLE
	122
259b6cb3	123	#undef TRACE_SYSCALL_TABLE
f7bdf4db	124	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
259b6cb3	125	[ _nr ] = { \
f7bdf4db	126	.func = __event_probe__##_template, \
259b6cb3	127	.nrargs = (_nrargs), \
f7bdf4db MD	128	.fields = __event_fields___##_template, \
f7bdf4db MD	129	.desc = &__event_desc___##_name, \
259b6cb3 MD	130	},
259b6cb3 MD	131
49c50022	132	static const struct trace_syscall_entry sc_table[] = {
177b3692 MD	133	#include "instrumentation/syscalls/headers/syscalls_integers.h"
177b3692 MD	134	#include "instrumentation/syscalls/headers/syscalls_pointers.h"
259b6cb3 MD	135	};
259b6cb3 MD	136
a93244f8 MD	137	#undef TRACE_SYSCALL_TABLE
	138	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
	139	[ _nr ] = { \
	140	.func = __event_probe__##compat_##_template, \
	141	.nrargs = (_nrargs), \
	142	.fields = __event_fields___##compat_##_template,\
	143	.desc = &__event_desc___##compat_##_name, \
	144	},
	145
	146	/* Create compatibility syscall table */
	147	const struct trace_syscall_entry compat_sc_table[] = {
	148	#include "instrumentation/syscalls/headers/compat_syscalls_integers.h"
	149	#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
	150	};
259b6cb3	151
a93244f8	152	#undef CREATE_SYSCALL_TABLE
2faf7d1b	153
a90917c3	154	static void syscall_entry_unknown(struct lttng_event *event,
f405cfce MD	155	struct pt_regs *regs, unsigned int id)
	156	{
	157	unsigned long args[UNKNOWN_SYSCALL_NRARGS];
f405cfce	158
f405cfce	159	syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
a93244f8 MD	160	if (unlikely(is_compat_task()))
	161	__event_probe__compat_sys_unknown(event, id, args);
	162	else
	163	__event_probe__sys_unknown(event, id, args);
f405cfce MD	164	}
f405cfce MD	165
2faf7d1b	166	void syscall_entry_probe(void __data, struct pt_regs regs, long id)
259b6cb3	167	{
a90917c3 MD	168	struct lttng_channel *chan = __data;
a90917c3 MD	169	struct lttng_event event, unknown_event;
49c50022 MD	170	const struct trace_syscall_entry table, entry;
49c50022 MD	171	size_t table_len;
259b6cb3	172
b76dc1a0	173	if (unlikely(is_compat_task())) {
49c50022	174	table = compat_sc_table;
a93244f8	175	table_len = ARRAY_SIZE(compat_sc_table);
49c50022 MD	176	unknown_event = chan->sc_compat_unknown;
	177	} else {
	178	table = sc_table;
	179	table_len = ARRAY_SIZE(sc_table);
	180	unknown_event = chan->sc_unknown;
b76dc1a0	181	}
49c50022 MD	182	if (unlikely(id >= table_len)) {
49c50022 MD	183	syscall_entry_unknown(unknown_event, regs, id);
259b6cb3	184	return;
f405cfce	185	}
49c50022 MD	186	if (unlikely(is_compat_task()))
	187	event = chan->compat_sc_table[id];
	188	else
	189	event = chan->sc_table[id];
f405cfce	190	if (unlikely(!event)) {
49c50022	191	syscall_entry_unknown(unknown_event, regs, id);
f405cfce MD	192	return;
f405cfce MD	193	}
49c50022	194	entry = &table[id];
f405cfce	195	WARN_ON_ONCE(!entry);
259b6cb3 MD	196
	197	switch (entry->nrargs) {
	198	case 0:
	199	{
	200	void (fptr)(void __data) = entry->func;
	201
	202	fptr(event);
	203	break;
	204	}
	205	case 1:
	206	{
	207	void (fptr)(void __data, unsigned long arg0) = entry->func;
	208	unsigned long args[1];
	209
	210	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	211	fptr(event, args[0]);
	212	break;
	213	}
	214	case 2:
	215	{
	216	void (fptr)(void __data,
	217	unsigned long arg0,
	218	unsigned long arg1) = entry->func;
	219	unsigned long args[2];
	220
	221	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	222	fptr(event, args[0], args[1]);
	223	break;
	224	}
	225	case 3:
	226	{
	227	void (fptr)(void __data,
	228	unsigned long arg0,
	229	unsigned long arg1,
	230	unsigned long arg2) = entry->func;
	231	unsigned long args[3];
	232
	233	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	234	fptr(event, args[0], args[1], args[2]);
	235	break;
	236	}
	237	case 4:
	238	{
	239	void (fptr)(void __data,
	240	unsigned long arg0,
	241	unsigned long arg1,
	242	unsigned long arg2,
	243	unsigned long arg3) = entry->func;
	244	unsigned long args[4];
	245
	246	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	247	fptr(event, args[0], args[1], args[2], args[3]);
	248	break;
	249	}
	250	case 5:
	251	{
	252	void (fptr)(void __data,
	253	unsigned long arg0,
	254	unsigned long arg1,
	255	unsigned long arg2,
	256	unsigned long arg3,
	257	unsigned long arg4) = entry->func;
	258	unsigned long args[5];
	259
260	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
261	fptr(event, args[0], args[1], args[2], args[3], args[4]);
262	break;
263	}
264	case 6:
265	{
266	void (fptr)(void __data,
267	unsigned long arg0,
268	unsigned long arg1,
269	unsigned long arg2,
270	unsigned long arg3,
271	unsigned long arg4,
272	unsigned long arg5) = entry->func;
273	unsigned long args[6];
274
275	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
276	fptr(event, args[0], args[1], args[2],
277	args[3], args[4], args[5]);
278	break;
279	}
280	default:
281	break;
282	}
283	}
284
2a0c4816	285	/* noinline to diminish caller stack size */
49c50022 MD	286	static
49c50022 MD	287	int fill_table(const struct trace_syscall_entry *table, size_t table_len,
a90917c3	288	struct lttng_event *chan_table, struct lttng_channel chan, void *filter)
259b6cb3	289	{
2a0c4816	290	const struct lttng_event_desc *desc;
259b6cb3	291	unsigned int i;
49c50022 MD	292
	293	/* Allocate events for each syscall, insert into table */
	294	for (i = 0; i < table_len; i++) {
	295	struct lttng_kernel_event ev;
2a0c4816	296	desc = table[i].desc;
49c50022 MD	297
	298	if (!desc) {
	299	/* Unknown syscall */
	300	continue;
	301	}
	302	/*
	303	* Skip those already populated by previous failed
	304	* register for this channel.
	305	*/
	306	if (chan_table[i])
	307	continue;
	308	memset(&ev, 0, sizeof(ev));
f8695253 MD	309	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	310	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
49c50022	311	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	312	chan_table[i] = lttng_event_create(chan, &ev, filter,
49c50022 MD	313	desc);
	314	if (!chan_table[i]) {
	315	/*
	316	* If something goes wrong in event registration
	317	* after the first one, we have no choice but to
	318	* leave the previous events in there, until
	319	* deleted by session teardown.
	320	*/
	321	return -EINVAL;
	322	}
	323	}
	324	return 0;
	325	}
	326
a90917c3	327	int lttng_syscalls_register(struct lttng_channel chan, void filter)
49c50022	328	{
2a0c4816	329	struct lttng_kernel_event ev;
259b6cb3 MD	330	int ret;
	331
	332	wrapper_vmalloc_sync_all();
259b6cb3 MD	333
	334	if (!chan->sc_table) {
	335	/* create syscall table mapping syscall to events */
a90917c3	336	chan->sc_table = kzalloc(sizeof(struct lttng_event *)
259b6cb3 MD	337	* ARRAY_SIZE(sc_table), GFP_KERNEL);
	338	if (!chan->sc_table)
	339	return -ENOMEM;
	340	}
	341
49c50022 MD	342	#ifdef CONFIG_COMPAT
	343	if (!chan->compat_sc_table) {
	344	/* create syscall table mapping compat syscall to events */
a90917c3	345	chan->compat_sc_table = kzalloc(sizeof(struct lttng_event *)
a93244f8	346	* ARRAY_SIZE(compat_sc_table), GFP_KERNEL);
49c50022 MD	347	if (!chan->compat_sc_table)
	348	return -ENOMEM;
	349	}
	350	#endif
f405cfce	351	if (!chan->sc_unknown) {
f405cfce MD	352	const struct lttng_event_desc *desc =
f405cfce MD	353	&__event_desc___sys_unknown;
2f804c0a	354
f405cfce	355	memset(&ev, 0, sizeof(ev));
f8695253 MD	356	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	357	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
f405cfce	358	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	359	chan->sc_unknown = lttng_event_create(chan, &ev, filter,
f405cfce MD	360	desc);
	361	if (!chan->sc_unknown) {
	362	return -EINVAL;
	363	}
	364	}
	365
b76dc1a0	366	if (!chan->sc_compat_unknown) {
b76dc1a0 MD	367	const struct lttng_event_desc *desc =
	368	&__event_desc___compat_sys_unknown;
	369
	370	memset(&ev, 0, sizeof(ev));
f8695253 MD	371	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	372	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
b76dc1a0	373	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	374	chan->sc_compat_unknown = lttng_event_create(chan, &ev, filter,
b76dc1a0 MD	375	desc);
	376	if (!chan->sc_compat_unknown) {
	377	return -EINVAL;
	378	}
	379	}
	380
2f804c0a	381	if (!chan->sc_exit) {
2f804c0a MD	382	const struct lttng_event_desc *desc =
	383	&__event_desc___exit_syscall;
	384
	385	memset(&ev, 0, sizeof(ev));
f8695253 MD	386	strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
f8695253 MD	387	ev.name[LTTNG_KERNEL_SYM_NAME_LEN - 1] = '\0';
2f804c0a	388	ev.instrumentation = LTTNG_KERNEL_NOOP;
a90917c3	389	chan->sc_exit = lttng_event_create(chan, &ev, filter,
2f804c0a MD	390	desc);
	391	if (!chan->sc_exit) {
	392	return -EINVAL;
	393	}
	394	}
	395
49c50022 MD	396	ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
	397	chan->sc_table, chan, filter);
	398	if (ret)
	399	return ret;
	400	#ifdef CONFIG_COMPAT
a93244f8	401	ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
49c50022 MD	402	chan->compat_sc_table, chan, filter);
	403	if (ret)
	404	return ret;
	405	#endif
259b6cb3 MD	406	ret = tracepoint_probe_register("sys_enter",
259b6cb3 MD	407	(void *) syscall_entry_probe, chan);
63728b02 MD	408	if (ret)
	409	return ret;
	410	/*
	411	* We change the name of sys_exit tracepoint due to namespace
	412	* conflict with sys_exit syscall entry.
	413	*/
	414	ret = tracepoint_probe_register("sys_exit",
2c01ec07	415	(void *) __event_probe__exit_syscall,
2f804c0a	416	chan->sc_exit);
63728b02 MD	417	if (ret) {
	418	WARN_ON_ONCE(tracepoint_probe_unregister("sys_enter",
	419	(void *) syscall_entry_probe, chan));
	420	}
259b6cb3 MD	421	return ret;
	422	}
	423
	424	/*
	425	* Only called at session destruction.
	426	*/
a90917c3	427	int lttng_syscalls_unregister(struct lttng_channel *chan)
259b6cb3 MD	428	{
	429	int ret;
	430
	431	if (!chan->sc_table)
	432	return 0;
63728b02	433	ret = tracepoint_probe_unregister("sys_exit",
2c01ec07	434	(void *) __event_probe__exit_syscall,
2f804c0a	435	chan->sc_exit);
63728b02 MD	436	if (ret)
63728b02 MD	437	return ret;
259b6cb3 MD	438	ret = tracepoint_probe_unregister("sys_enter",
	439	(void *) syscall_entry_probe, chan);
	440	if (ret)
	441	return ret;
a90917c3	442	/* lttng_event destroy will be performed by lttng_session_destroy() */
259b6cb3	443	kfree(chan->sc_table);
49c50022 MD	444	#ifdef CONFIG_COMPAT
	445	kfree(chan->compat_sc_table);
	446	#endif
259b6cb3 MD	447	return 0;
259b6cb3 MD	448	}