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

/*
 * lttng-syscalls.c
 *
 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * LTTng sched probes.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

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

#include "ltt-events.h"

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

/* Hijack probe callback for system calls */
#define TP_PROBE_CB(_template)		&syscall_entry_probe
#define TP_MODULE_OVERRIDE

#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers

#include "instrumentation/syscalls/headers/syscalls.h"

#undef TP_MODULE_OVERRIDE
#undef TP_PROBE_CB
#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 struct trace_syscall_entry sc_table[] = {
#include "instrumentation/syscalls/headers/syscalls.h"
};

#undef CREATE_SYSCALL_TABLE

static void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
{
	struct trace_syscall_entry *entry;
	struct ltt_channel *chan = __data;
	struct ltt_event *event;

	if (unlikely(id >= ARRAY_SIZE(sc_table)))
		return;
	entry = &sc_table[id];
	if (unlikely(!entry->func))
		return;
	event = chan->sc_table[id];
	WARN_ON_ONCE(!event);

	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;
	}
}

int lttng_syscalls_register(struct ltt_channel *chan, void *filter)
{
	unsigned int i;
	int ret;

	wrapper_vmalloc_sync_all();

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

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

		if (!desc)
			continue;
		/*
		 * Skip those already populated by previous failed
		 * register for this channel.
		 */
		if (chan->sc_table[i])
			continue;
		memset(&ev, 0, sizeof(ev));
		strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
		ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
		ev.instrumentation = LTTNG_KERNEL_NOOP;
		chan->sc_table[i] = ltt_event_create(chan, &ev, filter,
						     desc);
		if (!chan->sc_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;
		}
	}
	ret = tracepoint_probe_register("sys_enter",
			(void *) syscall_entry_probe, chan);
	return ret;
}

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

	if (!chan->sc_table)
		return 0;
	ret = tracepoint_probe_unregister("sys_enter",
			(void *) syscall_entry_probe, chan);
	if (ret)
		return ret;
	/* ltt_event destroy will be performed by ltt_session_destroy() */
	kfree(chan->sc_table);
	return 0;
}
Commit	Line	Data
259b6cb3 MD	1	/*
	2	* lttng-syscalls.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* LTTng sched probes.
	7	*
	8	* Dual LGPL v2.1/GPL v2 license.
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/slab.h>
	13	#include <asm/ptrace.h>
	14	#include <asm/syscall.h>
	15
	16	#include "ltt-events.h"
	17
	18	static void syscall_entry_probe(void __data, struct pt_regs regs, long id);
	19
f7bdf4db MD	20	/*
	21	* Take care of NOARGS not supported by mainline.
	22	*/
	23	#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
	24	#define DEFINE_EVENT_NOARGS(template, name)
	25	#define TRACE_EVENT_NOARGS(name, struct, assign, print)
	26
259b6cb3 MD	27	/*
	28	* Create LTTng tracepoint probes.
	29	*/
	30	#define LTTNG_PACKAGE_BUILD
	31	#define CREATE_TRACE_POINTS
	32
	33	/* Hijack probe callback for system calls */
	34	#define TP_PROBE_CB(_template) &syscall_entry_probe
	35	#define TP_MODULE_OVERRIDE
	36
	37	#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
	38
	39	#include "instrumentation/syscalls/headers/syscalls.h"
	40
	41	#undef TP_MODULE_OVERRIDE
	42	#undef TP_PROBE_CB
	43	#undef LTTNG_PACKAGE_BUILD
	44	#undef CREATE_TRACE_POINTS
	45
	46	struct trace_syscall_entry {
	47	void *func;
f7bdf4db	48	const struct lttng_event_desc *desc;
259b6cb3 MD	49	const struct lttng_event_field *fields;
	50	unsigned int nrargs;
	51	};
	52
259b6cb3 MD	53	#define CREATE_SYSCALL_TABLE
	54
	55	#undef TRACE_SYSCALL_TABLE
f7bdf4db	56	#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs) \
259b6cb3	57	[ _nr ] = { \
f7bdf4db	58	.func = __event_probe__##_template, \
259b6cb3	59	.nrargs = (_nrargs), \
f7bdf4db MD	60	.fields = __event_fields___##_template, \
f7bdf4db MD	61	.desc = &__event_desc___##_name, \
259b6cb3 MD	62	},
	63
	64	static struct trace_syscall_entry sc_table[] = {
	65	#include "instrumentation/syscalls/headers/syscalls.h"
	66	};
	67
	68	#undef CREATE_SYSCALL_TABLE
	69
	70	static void syscall_entry_probe(void __data, struct pt_regs regs, long id)
	71	{
	72	struct trace_syscall_entry *entry;
	73	struct ltt_channel *chan = __data;
	74	struct ltt_event *event;
	75
	76	if (unlikely(id >= ARRAY_SIZE(sc_table)))
	77	return;
	78	entry = &sc_table[id];
	79	if (unlikely(!entry->func))
	80	return;
	81	event = chan->sc_table[id];
	82	WARN_ON_ONCE(!event);
	83
	84	switch (entry->nrargs) {
	85	case 0:
	86	{
	87	void (fptr)(void __data) = entry->func;
	88
	89	fptr(event);
	90	break;
	91	}
	92	case 1:
	93	{
	94	void (fptr)(void __data, unsigned long arg0) = entry->func;
	95	unsigned long args[1];
	96
	97	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	98	fptr(event, args[0]);
	99	break;
	100	}
	101	case 2:
	102	{
	103	void (fptr)(void __data,
	104	unsigned long arg0,
	105	unsigned long arg1) = entry->func;
	106	unsigned long args[2];
	107
	108	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	109	fptr(event, args[0], args[1]);
	110	break;
	111	}
	112	case 3:
	113	{
	114	void (fptr)(void __data,
	115	unsigned long arg0,
	116	unsigned long arg1,
	117	unsigned long arg2) = entry->func;
	118	unsigned long args[3];
	119
	120	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
	121	fptr(event, args[0], args[1], args[2]);
	122	break;
	123	}
	124	case 4:
	125	{
126	void (fptr)(void __data,
127	unsigned long arg0,
128	unsigned long arg1,
129	unsigned long arg2,
130	unsigned long arg3) = entry->func;
131	unsigned long args[4];
132
133	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
134	fptr(event, args[0], args[1], args[2], args[3]);
135	break;
136	}
137	case 5:
138	{
139	void (fptr)(void __data,
140	unsigned long arg0,
141	unsigned long arg1,
142	unsigned long arg2,
143	unsigned long arg3,
144	unsigned long arg4) = entry->func;
145	unsigned long args[5];
146
147	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
148	fptr(event, args[0], args[1], args[2], args[3], args[4]);
149	break;
150	}
151	case 6:
152	{
153	void (fptr)(void __data,
154	unsigned long arg0,
155	unsigned long arg1,
156	unsigned long arg2,
157	unsigned long arg3,
158	unsigned long arg4,
159	unsigned long arg5) = entry->func;
160	unsigned long args[6];
161
162	syscall_get_arguments(current, regs, 0, entry->nrargs, args);
163	fptr(event, args[0], args[1], args[2],
164	args[3], args[4], args[5]);
165	break;
166	}
167	default:
168	break;
169	}
170	}
171
259b6cb3 MD	172	int lttng_syscalls_register(struct ltt_channel chan, void filter)
	173	{
	174	unsigned int i;
	175	int ret;
	176
	177	wrapper_vmalloc_sync_all();
259b6cb3 MD	178
	179	if (!chan->sc_table) {
	180	/* create syscall table mapping syscall to events */
	181	chan->sc_table = kzalloc(sizeof(struct ltt_event *)
	182	* ARRAY_SIZE(sc_table), GFP_KERNEL);
	183	if (!chan->sc_table)
	184	return -ENOMEM;
	185	}
	186
	187	/* Allocate events for each syscall, insert into table */
	188	for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
	189	struct lttng_kernel_event ev;
	190	const struct lttng_event_desc *desc = sc_table[i].desc;
	191
	192	if (!desc)
	193	continue;
	194	/*
	195	* Skip those already populated by previous failed
	196	* register for this channel.
	197	*/
	198	if (chan->sc_table[i])
	199	continue;
	200	memset(&ev, 0, sizeof(ev));
	201	strncpy(ev.name, desc->name, LTTNG_SYM_NAME_LEN);
	202	ev.name[LTTNG_SYM_NAME_LEN - 1] = '\0';
	203	ev.instrumentation = LTTNG_KERNEL_NOOP;
	204	chan->sc_table[i] = ltt_event_create(chan, &ev, filter,
	205	desc);
	206	if (!chan->sc_table[i]) {
	207	/*
	208	* If something goes wrong in event registration
	209	* after the first one, we have no choice but to
	210	* leave the previous events in there, until
	211	* deleted by session teardown.
	212	*/
	213	return -EINVAL;
	214	}
	215	}
	216	ret = tracepoint_probe_register("sys_enter",
	217	(void *) syscall_entry_probe, chan);
	218	return ret;
	219	}
	220
	221	/*
	222	* Only called at session destruction.
	223	*/
	224	int lttng_syscalls_unregister(struct ltt_channel *chan)
	225	{
	226	int ret;
	227
	228	if (!chan->sc_table)
	229	return 0;
	230	ret = tracepoint_probe_unregister("sys_enter",
	231	(void *) syscall_entry_probe, chan);
	232	if (ret)
	233	return ret;
	234	/* ltt_event destroy will be performed by ltt_session_destroy() */
	235	kfree(chan->sc_table);
	236	return 0;
	237	}