Cleanup: Move patches.i to include/generated/
[lttng-modules.git] / lttng-syscalls.c
index 62ed24aa66723c2cb16b8abe2a83cd6b5a8ccb48..a5b5f403fe359e6531650111fc05cb82a6c60aba 100644 (file)
@@ -1,33 +1,33 @@
-/*
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
  * 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 <linux/err.h>
+#include <linux/bitmap.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/seq_file.h>
+#include <linux/stringify.h>
+#include <linux/file.h>
+#include <linux/anon_inodes.h>
+#include <linux/fcntl.h>
 #include <asm/ptrace.h>
 #include <asm/syscall.h>
 
-#include "wrapper/tracepoint.h"
-#include "lttng-events.h"
+#include <lttng/bitfield.h>
+#include <wrapper/tracepoint.h>
+#include <wrapper/file.h>
+#include <wrapper/rcu.h>
+#include <wrapper/syscall.h>
+#include <lttng/events.h>
 
 #ifndef CONFIG_COMPAT
 # ifndef is_compat_task
 # endif
 #endif
 
+/* in_compat_syscall appears in kernel 4.6. */
+#ifndef in_compat_syscall
+ #define in_compat_syscall()   is_compat_task()
+#endif
+
+enum sc_type {
+       SC_TYPE_ENTRY,
+       SC_TYPE_EXIT,
+       SC_TYPE_COMPAT_ENTRY,
+       SC_TYPE_COMPAT_EXIT,
+};
+
+#define SYSCALL_ENTRY_TOK              syscall_entry_
+#define COMPAT_SYSCALL_ENTRY_TOK       compat_syscall_entry_
+#define SYSCALL_EXIT_TOK               syscall_exit_
+#define COMPAT_SYSCALL_EXIT_TOK                compat_syscall_exit_
+
+#define SYSCALL_ENTRY_STR              __stringify(SYSCALL_ENTRY_TOK)
+#define COMPAT_SYSCALL_ENTRY_STR       __stringify(COMPAT_SYSCALL_ENTRY_TOK)
+#define SYSCALL_EXIT_STR               __stringify(SYSCALL_EXIT_TOK)
+#define COMPAT_SYSCALL_EXIT_STR                __stringify(COMPAT_SYSCALL_EXIT_TOK)
+
 static
 void syscall_entry_probe(void *__data, struct pt_regs *regs, long id);
+static
+void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret);
 
 /*
  * Forward declarations for old kernels.
@@ -47,13 +71,26 @@ struct oldold_utsname;
 struct old_utsname;
 struct sel_arg_struct;
 struct mmap_arg_struct;
+struct file_handle;
+struct user_msghdr;
 
 /*
- * Take care of NOARGS not supported by mainline.
+ * Forward declaration for kernels >= 5.6
  */
-#define DECLARE_EVENT_CLASS_NOARGS(name, tstruct, assign, print)
-#define DEFINE_EVENT_NOARGS(template, name)
-#define TRACE_EVENT_NOARGS(name, struct, assign, print)
+struct timex;
+struct timeval;
+struct itimerval;
+struct itimerspec;
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,6,0))
+typedef __kernel_old_time_t time_t;
+#endif
+
+#ifdef IA32_NR_syscalls
+#define NR_compat_syscalls IA32_NR_syscalls
+#else
+#define NR_compat_syscalls NR_syscalls
+#endif
 
 /*
  * Create LTTng tracepoint probes.
@@ -61,62 +98,185 @@ struct mmap_arg_struct;
 #define LTTNG_PACKAGE_BUILD
 #define CREATE_TRACE_POINTS
 #define TP_MODULE_NOINIT
-#define TRACE_INCLUDE_PATH ../instrumentation/syscalls/headers
+#define TRACE_INCLUDE_PATH instrumentation/syscalls/headers
 
 #define PARAMS(args...)        args
 
-/* Hijack probe callback for system calls */
+/* Handle unknown syscalls */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM syscalls_unknown
+#include <instrumentation/syscalls/headers/syscalls_unknown.h>
+#undef TRACE_SYSTEM
+
+#define SC_ENTER
+
+#undef sc_exit
+#define sc_exit(...)
+#undef sc_in
+#define sc_in(...)     __VA_ARGS__
+#undef sc_out
+#define sc_out(...)
+#undef sc_inout
+#define sc_inout(...)  __VA_ARGS__
+
+/* Hijack probe callback for system call enter */
 #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)
+#define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
+       LTTNG_TRACEPOINT_EVENT(syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
+       LTTNG_TRACEPOINT_EVENT_CODE(syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_locvar), PARAMS(_code_pre),                             \
+               PARAMS(_fields), PARAMS(_code_post))
+#define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
+       LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(syscall_entry_##_name, PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)            \
+       LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(syscall_entry_##_template, syscall_entry_##_name)
+/* Enumerations only defined at first inclusion. */
+#define SC_LTTNG_TRACEPOINT_ENUM(_name, _values) \
+       LTTNG_TRACEPOINT_ENUM(_name, PARAMS(_values))
 #undef TRACE_SYSTEM
-#define TRACE_SYSTEM syscalls_integers
-#include "instrumentation/syscalls/headers/syscalls_integers.h"
+#define TRACE_SYSTEM syscall_entry_integers
+#define TRACE_INCLUDE_FILE syscalls_integers
+#include <instrumentation/syscalls/headers/syscalls_integers.h>
+#undef TRACE_INCLUDE_FILE
 #undef TRACE_SYSTEM
-#define TRACE_SYSTEM syscalls_pointers
-#include "instrumentation/syscalls/headers/syscalls_pointers.h"
+#define TRACE_SYSTEM syscall_entry_pointers
+#define TRACE_INCLUDE_FILE syscalls_pointers
+#include <instrumentation/syscalls/headers/syscalls_pointers.h>
+#undef TRACE_INCLUDE_FILE
 #undef TRACE_SYSTEM
-#undef SC_TRACE_EVENT
-#undef SC_DECLARE_EVENT_CLASS_NOARGS
-#undef SC_DEFINE_EVENT_NOARGS
+#undef SC_LTTNG_TRACEPOINT_ENUM
+#undef SC_LTTNG_TRACEPOINT_EVENT_CODE
+#undef SC_LTTNG_TRACEPOINT_EVENT
+#undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
+#undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
+#undef TP_PROBE_CB
+#undef _TRACE_SYSCALLS_INTEGERS_H
+#undef _TRACE_SYSCALLS_POINTERS_H
 
-#define TRACE_SYSTEM syscalls_unknown
-#include "instrumentation/syscalls/headers/syscalls_unknown.h"
+/* Hijack probe callback for compat system call enter */
+#define TP_PROBE_CB(_template)         &syscall_entry_probe
+#define LTTNG_SC_COMPAT
+#define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
+       LTTNG_TRACEPOINT_EVENT(compat_syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
+       LTTNG_TRACEPOINT_EVENT_CODE(compat_syscall_entry_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
+#define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
+       LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(compat_syscall_entry_##_name, PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)            \
+       LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(compat_syscall_entry_##_template, \
+               compat_syscall_entry_##_name)
+/* Enumerations only defined at inital inclusion (not here). */
+#define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
+#define TRACE_SYSTEM compat_syscall_entry_integers
+#define TRACE_INCLUDE_FILE compat_syscalls_integers
+#include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
+#undef TRACE_INCLUDE_FILE
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM compat_syscall_entry_pointers
+#define TRACE_INCLUDE_FILE compat_syscalls_pointers
+#include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
+#undef TRACE_INCLUDE_FILE
 #undef TRACE_SYSTEM
+#undef SC_LTTNG_TRACEPOINT_ENUM
+#undef SC_LTTNG_TRACEPOINT_EVENT_CODE
+#undef SC_LTTNG_TRACEPOINT_EVENT
+#undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
+#undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
+#undef TP_PROBE_CB
+#undef _TRACE_SYSCALLS_INTEGERS_H
+#undef _TRACE_SYSCALLS_POINTERS_H
+#undef LTTNG_SC_COMPAT
 
-/* For compat syscalls */
-#undef _TRACE_SYSCALLS_integers_H
-#undef _TRACE_SYSCALLS_pointers_H
+#undef SC_ENTER
 
-/* Hijack probe callback for system calls */
+#define SC_EXIT
+
+#undef sc_exit
+#define sc_exit(...)           __VA_ARGS__
+#undef sc_in
+#define sc_in(...)
+#undef sc_out
+#define sc_out(...)            __VA_ARGS__
+#undef sc_inout
+#define sc_inout(...)          __VA_ARGS__
+
+/* Hijack probe callback for system call exit */
+#define TP_PROBE_CB(_template)         &syscall_exit_probe
+#define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
+       LTTNG_TRACEPOINT_EVENT(syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
+       LTTNG_TRACEPOINT_EVENT_CODE(syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
+#define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
+       LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(syscall_exit_##_name, PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)            \
+       LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(syscall_exit_##_template,        \
+               syscall_exit_##_name)
+/* Enumerations only defined at inital inclusion (not here). */
+#define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
+#define TRACE_SYSTEM syscall_exit_integers
+#define TRACE_INCLUDE_FILE syscalls_integers
+#include <instrumentation/syscalls/headers/syscalls_integers.h>
+#undef TRACE_INCLUDE_FILE
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM syscall_exit_pointers
+#define TRACE_INCLUDE_FILE syscalls_pointers
+#include <instrumentation/syscalls/headers/syscalls_pointers.h>
+#undef TRACE_INCLUDE_FILE
+#undef TRACE_SYSTEM
+#undef SC_LTTNG_TRACEPOINT_ENUM
+#undef SC_LTTNG_TRACEPOINT_EVENT_CODE
+#undef SC_LTTNG_TRACEPOINT_EVENT
+#undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
+#undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 #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_SYSCALLS_INTEGERS_H
+#undef _TRACE_SYSCALLS_POINTERS_H
+
+
+/* Hijack probe callback for compat system call exit */
+#define TP_PROBE_CB(_template)         &syscall_exit_probe
+#define LTTNG_SC_COMPAT
+#define SC_LTTNG_TRACEPOINT_EVENT(_name, _proto, _args, _fields) \
+       LTTNG_TRACEPOINT_EVENT(compat_syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_CODE(_name, _proto, _args, _locvar, _code_pre, _fields, _code_post) \
+       LTTNG_TRACEPOINT_EVENT_CODE(compat_syscall_exit_##_name, PARAMS(_proto), PARAMS(_args), \
+               PARAMS(_locvar), PARAMS(_code_pre), PARAMS(_fields), PARAMS(_code_post))
+#define SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(_name, _fields) \
+       LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS(compat_syscall_exit_##_name, PARAMS(_fields))
+#define SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(_template, _name)            \
+       LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS(compat_syscall_exit_##_template, \
+               compat_syscall_exit_##_name)
+/* Enumerations only defined at inital inclusion (not here). */
+#define SC_LTTNG_TRACEPOINT_ENUM(_name, _values)
+#define TRACE_SYSTEM compat_syscall_exit_integers
+#define TRACE_INCLUDE_FILE compat_syscalls_integers
+#include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
+#undef TRACE_INCLUDE_FILE
 #undef TRACE_SYSTEM
-#define TRACE_SYSTEM compat_syscalls_pointers
-#include "instrumentation/syscalls/headers/compat_syscalls_pointers.h"
+#define TRACE_SYSTEM compat_syscall_exit_pointers
+#define TRACE_INCLUDE_FILE compat_syscalls_pointers
+#include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
+#undef TRACE_INCLUDE_FILE
 #undef TRACE_SYSTEM
-#undef SC_TRACE_EVENT
-#undef SC_DECLARE_EVENT_CLASS_NOARGS
-#undef SC_DEFINE_EVENT_NOARGS
+#undef SC_LTTNG_TRACEPOINT_ENUM
+#undef SC_LTTNG_TRACEPOINT_EVENT_CODE
+#undef SC_LTTNG_TRACEPOINT_EVENT
+#undef SC_LTTNG_TRACEPOINT_EVENT_CLASS_NOARGS
+#undef SC_LTTNG_TRACEPOINT_EVENT_INSTANCE_NOARGS
 #undef TP_PROBE_CB
+#undef _TRACE_SYSCALLS_INTEGERS_H
+#undef _TRACE_SYSCALLS_POINTERS_H
+#undef LTTNG_SC_COMPAT
+
+#undef SC_EXIT
 
 #undef TP_MODULE_NOINIT
 #undef LTTNG_PACKAGE_BUILD
@@ -131,47 +291,97 @@ struct trace_syscall_entry {
 
 #define CREATE_SYSCALL_TABLE
 
+#define SC_ENTER
+
+#undef sc_exit
+#define sc_exit(...)
+
 #undef TRACE_SYSCALL_TABLE
 #define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)    \
        [ _nr ] = {                                             \
-               .func = __event_probe__##_template,             \
+               .func = __event_probe__syscall_entry_##_template, \
                .nrargs = (_nrargs),                            \
-               .fields = __event_fields___##_template,         \
-               .desc = &__event_desc___##_name,                \
+               .fields = __event_fields___syscall_entry_##_template, \
+               .desc = &__event_desc___syscall_entry_##_name,  \
        },
 
+/* Syscall enter tracing table */
 static const struct trace_syscall_entry sc_table[] = {
-#include "instrumentation/syscalls/headers/syscalls_integers.h"
-#include "instrumentation/syscalls/headers/syscalls_pointers.h"
+#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,    \
+               .func = __event_probe__compat_syscall_entry_##_template, \
                .nrargs = (_nrargs),                            \
-               .fields = __event_fields___##compat_##_template,\
-               .desc = &__event_desc___##compat_##_name,       \
+               .fields = __event_fields___compat_syscall_entry_##_template, \
+               .desc = &__event_desc___compat_syscall_entry_##_name, \
        },
 
-/* Create compatibility syscall table */
+/* Compat syscall enter 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"
+#include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
+#include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
 };
 
+#undef SC_ENTER
+
+#define SC_EXIT
+
+#undef sc_exit
+#define sc_exit(...)           __VA_ARGS__
+
+#undef TRACE_SYSCALL_TABLE
+#define TRACE_SYSCALL_TABLE(_template, _name, _nr, _nrargs)    \
+       [ _nr ] = {                                             \
+               .func = __event_probe__syscall_exit_##_template, \
+               .nrargs = (_nrargs),                            \
+               .fields = __event_fields___syscall_exit_##_template, \
+               .desc = &__event_desc___syscall_exit_##_name, \
+       },
+
+/* Syscall exit table */
+static const struct trace_syscall_entry sc_exit_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_syscall_exit_##_template, \
+               .nrargs = (_nrargs),                            \
+               .fields = __event_fields___compat_syscall_exit_##_template, \
+               .desc = &__event_desc___compat_syscall_exit_##_name, \
+       },
+
+/* Compat syscall exit table */
+const struct trace_syscall_entry compat_sc_exit_table[] = {
+#include <instrumentation/syscalls/headers/compat_syscalls_integers.h>
+#include <instrumentation/syscalls/headers/compat_syscalls_pointers.h>
+};
+
+#undef SC_EXIT
+
 #undef CREATE_SYSCALL_TABLE
 
+struct lttng_syscall_filter {
+       DECLARE_BITMAP(sc, NR_syscalls);
+       DECLARE_BITMAP(sc_compat, NR_compat_syscalls);
+};
+
 static void syscall_entry_unknown(struct lttng_event *event,
        struct pt_regs *regs, unsigned int id)
 {
-       unsigned long args[UNKNOWN_SYSCALL_NRARGS];
+       unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-       syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args);
-       if (unlikely(is_compat_task()))
-               __event_probe__compat_sys_unknown(event, id, args);
+       lttng_syscall_get_arguments(current, regs, args);
+       if (unlikely(in_compat_syscall()))
+               __event_probe__compat_syscall_entry_unknown(event, id, args);
        else
-               __event_probe__sys_unknown(event, id, args);
+               __event_probe__syscall_entry_unknown(event, id, args);
 }
 
 void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
@@ -181,20 +391,40 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
        const struct trace_syscall_entry *table, *entry;
        size_t table_len;
 
-       if (unlikely(is_compat_task())) {
+       if (unlikely(in_compat_syscall())) {
+               struct lttng_syscall_filter *filter;
+
+               filter = lttng_rcu_dereference(chan->sc_filter);
+               if (filter) {
+                       if (id < 0 || id >= NR_compat_syscalls
+                               || !test_bit(id, filter->sc_compat)) {
+                               /* System call filtered out. */
+                               return;
+                       }
+               }
                table = compat_sc_table;
                table_len = ARRAY_SIZE(compat_sc_table);
                unknown_event = chan->sc_compat_unknown;
        } else {
+               struct lttng_syscall_filter *filter;
+
+               filter = lttng_rcu_dereference(chan->sc_filter);
+               if (filter) {
+                       if (id < 0 || id >= NR_syscalls
+                               || !test_bit(id, filter->sc)) {
+                               /* System call filtered out. */
+                               return;
+                       }
+               }
                table = sc_table;
                table_len = ARRAY_SIZE(sc_table);
                unknown_event = chan->sc_unknown;
        }
-       if (unlikely(id >= table_len)) {
+       if (unlikely(id < 0 || id >= table_len)) {
                syscall_entry_unknown(unknown_event, regs, id);
                return;
        }
-       if (unlikely(is_compat_task()))
+       if (unlikely(in_compat_syscall()))
                event = chan->compat_sc_table[id];
        else
                event = chan->sc_table[id];
@@ -216,9 +446,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
        case 1:
        {
                void (*fptr)(void *__data, unsigned long arg0) = entry->func;
-               unsigned long args[1];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0]);
                break;
        }
@@ -227,9 +457,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
                void (*fptr)(void *__data,
                        unsigned long arg0,
                        unsigned long arg1) = entry->func;
-               unsigned long args[2];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0], args[1]);
                break;
        }
@@ -239,9 +469,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
                        unsigned long arg0,
                        unsigned long arg1,
                        unsigned long arg2) = entry->func;
-               unsigned long args[3];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0], args[1], args[2]);
                break;
        }
@@ -252,9 +482,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
                        unsigned long arg1,
                        unsigned long arg2,
                        unsigned long arg3) = entry->func;
-               unsigned long args[4];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0], args[1], args[2], args[3]);
                break;
        }
@@ -266,9 +496,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
                        unsigned long arg2,
                        unsigned long arg3,
                        unsigned long arg4) = entry->func;
-               unsigned long args[5];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0], args[1], args[2], args[3], args[4]);
                break;
        }
@@ -281,9 +511,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
                        unsigned long arg3,
                        unsigned long arg4,
                        unsigned long arg5) = entry->func;
-               unsigned long args[6];
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
 
-               syscall_get_arguments(current, regs, 0, entry->nrargs, args);
+               lttng_syscall_get_arguments(current, regs, args);
                fptr(event, args[0], args[1], args[2],
                        args[3], args[4], args[5]);
                break;
@@ -293,10 +523,175 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id)
        }
 }
 
-/* noinline to diminish caller stack size */
+static void syscall_exit_unknown(struct lttng_event *event,
+       struct pt_regs *regs, int id, long ret)
+{
+       unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+       lttng_syscall_get_arguments(current, regs, args);
+       if (unlikely(in_compat_syscall()))
+               __event_probe__compat_syscall_exit_unknown(event, id, ret,
+                       args);
+       else
+               __event_probe__syscall_exit_unknown(event, id, ret, args);
+}
+
+void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret)
+{
+       struct lttng_channel *chan = __data;
+       struct lttng_event *event, *unknown_event;
+       const struct trace_syscall_entry *table, *entry;
+       size_t table_len;
+       long id;
+
+       id = syscall_get_nr(current, regs);
+       if (unlikely(in_compat_syscall())) {
+               struct lttng_syscall_filter *filter;
+
+               filter = lttng_rcu_dereference(chan->sc_filter);
+               if (filter) {
+                       if (id < 0 || id >= NR_compat_syscalls
+                               || !test_bit(id, filter->sc_compat)) {
+                               /* System call filtered out. */
+                               return;
+                       }
+               }
+               table = compat_sc_exit_table;
+               table_len = ARRAY_SIZE(compat_sc_exit_table);
+               unknown_event = chan->compat_sc_exit_unknown;
+       } else {
+               struct lttng_syscall_filter *filter;
+
+               filter = lttng_rcu_dereference(chan->sc_filter);
+               if (filter) {
+                       if (id < 0 || id >= NR_syscalls
+                               || !test_bit(id, filter->sc)) {
+                               /* System call filtered out. */
+                               return;
+                       }
+               }
+               table = sc_exit_table;
+               table_len = ARRAY_SIZE(sc_exit_table);
+               unknown_event = chan->sc_exit_unknown;
+       }
+       if (unlikely(id < 0 || id >= table_len)) {
+               syscall_exit_unknown(unknown_event, regs, id, ret);
+               return;
+       }
+       if (unlikely(in_compat_syscall()))
+               event = chan->compat_sc_exit_table[id];
+       else
+               event = chan->sc_exit_table[id];
+       if (unlikely(!event)) {
+               syscall_exit_unknown(unknown_event, regs, id, ret);
+               return;
+       }
+       entry = &table[id];
+       WARN_ON_ONCE(!entry);
+
+       switch (entry->nrargs) {
+       case 0:
+       {
+               void (*fptr)(void *__data, long ret) = entry->func;
+
+               fptr(event, ret);
+               break;
+       }
+       case 1:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0]);
+               break;
+       }
+       case 2:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0,
+                       unsigned long arg1) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0], args[1]);
+               break;
+       }
+       case 3:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0,
+                       unsigned long arg1,
+                       unsigned long arg2) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0], args[1], args[2]);
+               break;
+       }
+       case 4:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0,
+                       unsigned long arg1,
+                       unsigned long arg2,
+                       unsigned long arg3) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0], args[1], args[2], args[3]);
+               break;
+       }
+       case 5:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0,
+                       unsigned long arg1,
+                       unsigned long arg2,
+                       unsigned long arg3,
+                       unsigned long arg4) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0], args[1], args[2], args[3], args[4]);
+               break;
+       }
+       case 6:
+       {
+               void (*fptr)(void *__data,
+                       long ret,
+                       unsigned long arg0,
+                       unsigned long arg1,
+                       unsigned long arg2,
+                       unsigned long arg3,
+                       unsigned long arg4,
+                       unsigned long arg5) = entry->func;
+               unsigned long args[LTTNG_SYSCALL_NR_ARGS];
+
+               lttng_syscall_get_arguments(current, regs, args);
+               fptr(event, ret, args[0], args[1], args[2],
+                       args[3], args[4], args[5]);
+               break;
+       }
+       default:
+               break;
+       }
+}
+
+/*
+ * noinline to diminish caller stack size.
+ * Should be called with sessions lock held.
+ */
 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)
+       struct lttng_event **chan_table, struct lttng_channel *chan,
+       void *filter, enum sc_type type)
 {
        const struct lttng_event_desc *desc;
        unsigned int i;
@@ -317,30 +712,56 @@ int fill_table(const struct trace_syscall_entry *table, size_t table_len,
                if (chan_table[i])
                        continue;
                memset(&ev, 0, sizeof(ev));
-               strncpy(ev.name, desc->name, LTTNG_KERNEL_SYM_NAME_LEN);
+               switch (type) {
+               case SC_TYPE_ENTRY:
+                       strncpy(ev.name, SYSCALL_ENTRY_STR,
+                               LTTNG_KERNEL_SYM_NAME_LEN);
+                       break;
+               case SC_TYPE_EXIT:
+                       strncpy(ev.name, SYSCALL_EXIT_STR,
+                               LTTNG_KERNEL_SYM_NAME_LEN);
+                       break;
+               case SC_TYPE_COMPAT_ENTRY:
+                       strncpy(ev.name, COMPAT_SYSCALL_ENTRY_STR,
+                               LTTNG_KERNEL_SYM_NAME_LEN);
+                       break;
+               case SC_TYPE_COMPAT_EXIT:
+                       strncpy(ev.name, COMPAT_SYSCALL_EXIT_STR,
+                               LTTNG_KERNEL_SYM_NAME_LEN);
+                       break;
+               default:
+                       BUG_ON(1);
+                       break;
+               }
+               strncat(ev.name, desc->name,
+                       LTTNG_KERNEL_SYM_NAME_LEN - strlen(ev.name) - 1);
                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]) {
+               ev.instrumentation = LTTNG_KERNEL_SYSCALL;
+               chan_table[i] = _lttng_event_create(chan, &ev, filter,
+                                               desc, ev.instrumentation);
+               WARN_ON_ONCE(!chan_table[i]);
+               if (IS_ERR(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 PTR_ERR(chan_table[i]);
                }
        }
        return 0;
 }
 
+/*
+ * Should be called with sessions lock held.
+ */
 int lttng_syscalls_register(struct lttng_channel *chan, void *filter)
 {
        struct lttng_kernel_event ev;
        int ret;
 
-       wrapper_vmalloc_sync_all();
+       wrapper_vmalloc_sync_mappings();
 
        if (!chan->sc_table) {
                /* create syscall table mapping syscall to events */
@@ -349,6 +770,14 @@ int lttng_syscalls_register(struct lttng_channel *chan, void *filter)
                if (!chan->sc_table)
                        return -ENOMEM;
        }
+       if (!chan->sc_exit_table) {
+               /* create syscall table mapping syscall to events */
+               chan->sc_exit_table = kzalloc(sizeof(struct lttng_event *)
+                                       * ARRAY_SIZE(sc_exit_table), GFP_KERNEL);
+               if (!chan->sc_exit_table)
+                       return -ENOMEM;
+       }
+
 
 #ifdef CONFIG_COMPAT
        if (!chan->compat_sc_table) {
@@ -358,76 +787,123 @@ int lttng_syscalls_register(struct lttng_channel *chan, void *filter)
                if (!chan->compat_sc_table)
                        return -ENOMEM;
        }
+
+       if (!chan->compat_sc_exit_table) {
+               /* create syscall table mapping compat syscall to events */
+               chan->compat_sc_exit_table = kzalloc(sizeof(struct lttng_event *)
+                                       * ARRAY_SIZE(compat_sc_exit_table), GFP_KERNEL);
+               if (!chan->compat_sc_exit_table)
+                       return -ENOMEM;
+       }
 #endif
        if (!chan->sc_unknown) {
                const struct lttng_event_desc *desc =
-                       &__event_desc___sys_unknown;
+                       &__event_desc___syscall_entry_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;
+               ev.instrumentation = LTTNG_KERNEL_SYSCALL;
+               chan->sc_unknown = _lttng_event_create(chan, &ev, filter,
+                                               desc,
+                                               ev.instrumentation);
+               WARN_ON_ONCE(!chan->sc_unknown);
+               if (IS_ERR(chan->sc_unknown)) {
+                       return PTR_ERR(chan->sc_unknown);
                }
        }
 
        if (!chan->sc_compat_unknown) {
                const struct lttng_event_desc *desc =
-                       &__event_desc___compat_sys_unknown;
+                       &__event_desc___compat_syscall_entry_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;
+               ev.instrumentation = LTTNG_KERNEL_SYSCALL;
+               chan->sc_compat_unknown = _lttng_event_create(chan, &ev, filter,
+                                               desc,
+                                               ev.instrumentation);
+               WARN_ON_ONCE(!chan->sc_unknown);
+               if (IS_ERR(chan->sc_compat_unknown)) {
+                       return PTR_ERR(chan->sc_compat_unknown);
                }
        }
 
-       if (!chan->sc_exit) {
+       if (!chan->compat_sc_exit_unknown) {
                const struct lttng_event_desc *desc =
-                       &__event_desc___exit_syscall;
+                       &__event_desc___compat_syscall_exit_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_exit = lttng_event_create(chan, &ev, filter,
-                                                desc);
-               if (!chan->sc_exit) {
-                       return -EINVAL;
+               ev.instrumentation = LTTNG_KERNEL_SYSCALL;
+               chan->compat_sc_exit_unknown = _lttng_event_create(chan, &ev,
+                                               filter, desc,
+                                               ev.instrumentation);
+               WARN_ON_ONCE(!chan->compat_sc_exit_unknown);
+               if (IS_ERR(chan->compat_sc_exit_unknown)) {
+                       return PTR_ERR(chan->compat_sc_exit_unknown);
+               }
+       }
+
+       if (!chan->sc_exit_unknown) {
+               const struct lttng_event_desc *desc =
+                       &__event_desc___syscall_exit_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_SYSCALL;
+               chan->sc_exit_unknown = _lttng_event_create(chan, &ev, filter,
+                                               desc, ev.instrumentation);
+               WARN_ON_ONCE(!chan->sc_exit_unknown);
+               if (IS_ERR(chan->sc_exit_unknown)) {
+                       return PTR_ERR(chan->sc_exit_unknown);
                }
        }
 
        ret = fill_table(sc_table, ARRAY_SIZE(sc_table),
-                       chan->sc_table, chan, filter);
+                       chan->sc_table, chan, filter, SC_TYPE_ENTRY);
+       if (ret)
+               return ret;
+       ret = fill_table(sc_exit_table, ARRAY_SIZE(sc_exit_table),
+                       chan->sc_exit_table, chan, filter, SC_TYPE_EXIT);
        if (ret)
                return ret;
+
 #ifdef CONFIG_COMPAT
        ret = fill_table(compat_sc_table, ARRAY_SIZE(compat_sc_table),
-                       chan->compat_sc_table, chan, filter);
+                       chan->compat_sc_table, chan, filter,
+                       SC_TYPE_COMPAT_ENTRY);
        if (ret)
                return ret;
-#endif
-       ret = kabi_2635_tracepoint_probe_register("sys_enter",
-                       (void *) syscall_entry_probe, chan);
+       ret = fill_table(compat_sc_exit_table, ARRAY_SIZE(compat_sc_exit_table),
+                       chan->compat_sc_exit_table, chan, filter,
+                       SC_TYPE_COMPAT_EXIT);
        if (ret)
                return ret;
+#endif
+       if (!chan->sys_enter_registered) {
+               ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
+                               (void *) syscall_entry_probe, chan);
+               if (ret)
+                       return ret;
+               chan->sys_enter_registered = 1;
+       }
        /*
         * We change the name of sys_exit tracepoint due to namespace
         * conflict with sys_exit syscall entry.
         */
-       ret = kabi_2635_tracepoint_probe_register("sys_exit",
-                       (void *) __event_probe__exit_syscall,
-                       chan->sc_exit);
-       if (ret) {
-               WARN_ON_ONCE(kabi_2635_tracepoint_probe_unregister("sys_enter",
-                       (void *) syscall_entry_probe, chan));
+       if (!chan->sys_exit_registered) {
+               ret = lttng_wrapper_tracepoint_probe_register("sys_exit",
+                               (void *) syscall_exit_probe, chan);
+               if (ret) {
+                       WARN_ON_ONCE(lttng_wrapper_tracepoint_probe_unregister("sys_enter",
+                               (void *) syscall_entry_probe, chan));
+                       return ret;
+               }
+               chan->sys_exit_registered = 1;
        }
        return ret;
 }
@@ -441,19 +917,409 @@ int lttng_syscalls_unregister(struct lttng_channel *chan)
 
        if (!chan->sc_table)
                return 0;
-       ret = kabi_2635_tracepoint_probe_unregister("sys_exit",
-                       (void *) __event_probe__exit_syscall,
-                       chan->sc_exit);
-       if (ret)
-               return ret;
-       ret = kabi_2635_tracepoint_probe_unregister("sys_enter",
-                       (void *) syscall_entry_probe, chan);
-       if (ret)
-               return ret;
+       if (chan->sys_enter_registered) {
+               ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
+                               (void *) syscall_entry_probe, chan);
+               if (ret)
+                       return ret;
+               chan->sys_enter_registered = 0;
+       }
+       if (chan->sys_exit_registered) {
+               ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
+                               (void *) syscall_exit_probe, chan);
+               if (ret)
+                       return ret;
+               chan->sys_exit_registered = 0;
+       }
        /* lttng_event destroy will be performed by lttng_session_destroy() */
        kfree(chan->sc_table);
+       kfree(chan->sc_exit_table);
 #ifdef CONFIG_COMPAT
        kfree(chan->compat_sc_table);
+       kfree(chan->compat_sc_exit_table);
 #endif
+       kfree(chan->sc_filter);
+       return 0;
+}
+
+static
+int get_syscall_nr(const char *syscall_name)
+{
+       int syscall_nr = -1;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
+               const struct trace_syscall_entry *entry;
+               const char *it_name;
+
+               entry = &sc_table[i];
+               if (!entry->desc)
+                       continue;
+               it_name = entry->desc->name;
+               it_name += strlen(SYSCALL_ENTRY_STR);
+               if (!strcmp(syscall_name, it_name)) {
+                       syscall_nr = i;
+                       break;
+               }
+       }
+       return syscall_nr;
+}
+
+static
+int get_compat_syscall_nr(const char *syscall_name)
+{
+       int syscall_nr = -1;
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(compat_sc_table); i++) {
+               const struct trace_syscall_entry *entry;
+               const char *it_name;
+
+               entry = &compat_sc_table[i];
+               if (!entry->desc)
+                       continue;
+               it_name = entry->desc->name;
+               it_name += strlen(COMPAT_SYSCALL_ENTRY_STR);
+               if (!strcmp(syscall_name, it_name)) {
+                       syscall_nr = i;
+                       break;
+               }
+       }
+       return syscall_nr;
+}
+
+static
+uint32_t get_sc_tables_len(void)
+{
+       return ARRAY_SIZE(sc_table) + ARRAY_SIZE(compat_sc_table);
+}
+
+int lttng_syscall_filter_enable(struct lttng_channel *chan,
+               const char *name)
+{
+       int syscall_nr, compat_syscall_nr, ret;
+       struct lttng_syscall_filter *filter;
+
+       WARN_ON_ONCE(!chan->sc_table);
+
+       if (!name) {
+               /* Enable all system calls by removing filter */
+               if (chan->sc_filter) {
+                       filter = chan->sc_filter;
+                       rcu_assign_pointer(chan->sc_filter, NULL);
+                       synchronize_trace();
+                       kfree(filter);
+               }
+               chan->syscall_all = 1;
+               return 0;
+       }
+
+       if (!chan->sc_filter) {
+               if (chan->syscall_all) {
+                       /*
+                        * All syscalls are already enabled.
+                        */
+                       return -EEXIST;
+               }
+               filter = kzalloc(sizeof(struct lttng_syscall_filter),
+                               GFP_KERNEL);
+               if (!filter)
+                       return -ENOMEM;
+       } else {
+               filter = chan->sc_filter;
+       }
+       syscall_nr = get_syscall_nr(name);
+       compat_syscall_nr = get_compat_syscall_nr(name);
+       if (syscall_nr < 0 && compat_syscall_nr < 0) {
+               ret = -ENOENT;
+               goto error;
+       }
+       if (syscall_nr >= 0) {
+               if (test_bit(syscall_nr, filter->sc)) {
+                       ret = -EEXIST;
+                       goto error;
+               }
+               bitmap_set(filter->sc, syscall_nr, 1);
+       }
+       if (compat_syscall_nr >= 0) {
+               if (test_bit(compat_syscall_nr, filter->sc_compat)) {
+                       ret = -EEXIST;
+                       goto error;
+               }
+               bitmap_set(filter->sc_compat, compat_syscall_nr, 1);
+       }
+       if (!chan->sc_filter)
+               rcu_assign_pointer(chan->sc_filter, filter);
+       return 0;
+
+error:
+       if (!chan->sc_filter)
+               kfree(filter);
+       return ret;
+}
+
+int lttng_syscall_filter_disable(struct lttng_channel *chan,
+               const char *name)
+{
+       int syscall_nr, compat_syscall_nr, ret;
+       struct lttng_syscall_filter *filter;
+
+       WARN_ON_ONCE(!chan->sc_table);
+
+       if (!chan->sc_filter) {
+               if (!chan->syscall_all)
+                       return -EEXIST;
+               filter = kzalloc(sizeof(struct lttng_syscall_filter),
+                               GFP_KERNEL);
+               if (!filter)
+                       return -ENOMEM;
+               /* Trace all system calls, then apply disable. */
+               bitmap_set(filter->sc, 0, NR_syscalls);
+               bitmap_set(filter->sc_compat, 0, NR_compat_syscalls);
+       } else {
+               filter = chan->sc_filter;
+       }
+
+       if (!name) {
+               /* Fail if all syscalls are already disabled. */
+               if (bitmap_empty(filter->sc, NR_syscalls)
+                       && bitmap_empty(filter->sc_compat,
+                               NR_compat_syscalls)) {
+                       ret = -EEXIST;
+                       goto error;
+               }
+
+               /* Disable all system calls */
+               bitmap_clear(filter->sc, 0, NR_syscalls);
+               bitmap_clear(filter->sc_compat, 0, NR_compat_syscalls);
+               goto apply_filter;
+       }
+       syscall_nr = get_syscall_nr(name);
+       compat_syscall_nr = get_compat_syscall_nr(name);
+       if (syscall_nr < 0 && compat_syscall_nr < 0) {
+               ret = -ENOENT;
+               goto error;
+       }
+       if (syscall_nr >= 0) {
+               if (!test_bit(syscall_nr, filter->sc)) {
+                       ret = -EEXIST;
+                       goto error;
+               }
+               bitmap_clear(filter->sc, syscall_nr, 1);
+       }
+       if (compat_syscall_nr >= 0) {
+               if (!test_bit(compat_syscall_nr, filter->sc_compat)) {
+                       ret = -EEXIST;
+                       goto error;
+               }
+               bitmap_clear(filter->sc_compat, compat_syscall_nr, 1);
+       }
+apply_filter:
+       if (!chan->sc_filter)
+               rcu_assign_pointer(chan->sc_filter, filter);
+       chan->syscall_all = 0;
+       return 0;
+
+error:
+       if (!chan->sc_filter)
+               kfree(filter);
+       return ret;
+}
+
+static
+const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
+{
+       const struct trace_syscall_entry *entry;
+       int iter = 0;
+
+       for (entry = sc_table;
+                       entry < sc_table + ARRAY_SIZE(sc_table);
+                        entry++) {
+               if (iter++ >= *pos)
+                       return entry;
+       }
+       for (entry = compat_sc_table;
+                       entry < compat_sc_table + ARRAY_SIZE(compat_sc_table);
+                        entry++) {
+               if (iter++ >= *pos)
+                       return entry;
+       }
+       /* End of list */
+       return NULL;
+}
+
+static
+void *syscall_list_start(struct seq_file *m, loff_t *pos)
+{
+       return (void *) syscall_list_get_entry(pos);
+}
+
+static
+void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
+{
+       (*ppos)++;
+       return (void *) syscall_list_get_entry(ppos);
+}
+
+static
+void syscall_list_stop(struct seq_file *m, void *p)
+{
+}
+
+static
+int get_sc_table(const struct trace_syscall_entry *entry,
+               const struct trace_syscall_entry **table,
+               unsigned int *bitness)
+{
+       if (entry >= sc_table && entry < sc_table + ARRAY_SIZE(sc_table)) {
+               if (bitness)
+                       *bitness = BITS_PER_LONG;
+               if (table)
+                       *table = sc_table;
+               return 0;
+       }
+       if (!(entry >= compat_sc_table
+                       && entry < compat_sc_table + ARRAY_SIZE(compat_sc_table))) {
+               return -EINVAL;
+       }
+       if (bitness)
+               *bitness = 32;
+       if (table)
+               *table = compat_sc_table;
+       return 0;
+}
+
+static
+int syscall_list_show(struct seq_file *m, void *p)
+{
+       const struct trace_syscall_entry *table, *entry = p;
+       unsigned int bitness;
+       unsigned long index;
+       int ret;
+       const char *name;
+
+       ret = get_sc_table(entry, &table, &bitness);
+       if (ret)
+               return ret;
+       if (!entry->desc)
+               return 0;
+       if (table == sc_table) {
+               index = entry - table;
+               name = &entry->desc->name[strlen(SYSCALL_ENTRY_STR)];
+       } else {
+               index = (entry - table) + ARRAY_SIZE(sc_table);
+               name = &entry->desc->name[strlen(COMPAT_SYSCALL_ENTRY_STR)];
+       }
+       seq_printf(m,   "syscall { index = %lu; name = %s; bitness = %u; };\n",
+               index, name, bitness);
        return 0;
 }
+
+static
+const struct seq_operations lttng_syscall_list_seq_ops = {
+       .start = syscall_list_start,
+       .next = syscall_list_next,
+       .stop = syscall_list_stop,
+       .show = syscall_list_show,
+};
+
+static
+int lttng_syscall_list_open(struct inode *inode, struct file *file)
+{
+       return seq_open(file, &lttng_syscall_list_seq_ops);
+}
+
+const struct file_operations lttng_syscall_list_fops = {
+       .owner = THIS_MODULE,
+       .open = lttng_syscall_list_open,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = seq_release,
+};
+
+long lttng_channel_syscall_mask(struct lttng_channel *channel,
+               struct lttng_kernel_syscall_mask __user *usyscall_mask)
+{
+       uint32_t len, sc_tables_len, bitmask_len;
+       int ret = 0, bit;
+       char *tmp_mask;
+       struct lttng_syscall_filter *filter;
+
+       ret = get_user(len, &usyscall_mask->len);
+       if (ret)
+               return ret;
+       sc_tables_len = get_sc_tables_len();
+       bitmask_len = ALIGN(sc_tables_len, 8) >> 3;
+       if (len < sc_tables_len) {
+               return put_user(sc_tables_len, &usyscall_mask->len);
+       }
+       /* Array is large enough, we can copy array to user-space. */
+       tmp_mask = kzalloc(bitmask_len, GFP_KERNEL);
+       if (!tmp_mask)
+               return -ENOMEM;
+       filter = channel->sc_filter;
+
+       for (bit = 0; bit < ARRAY_SIZE(sc_table); bit++) {
+               char state;
+
+               if (channel->sc_table) {
+                       if (filter)
+                               state = test_bit(bit, filter->sc);
+                       else
+                               state = 1;
+               } else {
+                       state = 0;
+               }
+               bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
+       }
+       for (; bit < sc_tables_len; bit++) {
+               char state;
+
+               if (channel->compat_sc_table) {
+                       if (filter)
+                               state = test_bit(bit - ARRAY_SIZE(sc_table),
+                                               filter->sc_compat);
+                       else
+                               state = 1;
+               } else {
+                       state = 0;
+               }
+               bt_bitfield_write_be(tmp_mask, char, bit, 1, state);
+       }
+       if (copy_to_user(usyscall_mask->mask, tmp_mask, bitmask_len))
+               ret = -EFAULT;
+       kfree(tmp_mask);
+       return ret;
+}
+
+int lttng_abi_syscall_list(void)
+{
+       struct file *syscall_list_file;
+       int file_fd, ret;
+
+       file_fd = lttng_get_unused_fd();
+       if (file_fd < 0) {
+               ret = file_fd;
+               goto fd_error;
+       }
+
+       syscall_list_file = anon_inode_getfile("[lttng_syscall_list]",
+                                         &lttng_syscall_list_fops,
+                                         NULL, O_RDWR);
+       if (IS_ERR(syscall_list_file)) {
+               ret = PTR_ERR(syscall_list_file);
+               goto file_error;
+       }
+       ret = lttng_syscall_list_fops.open(NULL, syscall_list_file);
+       if (ret < 0)
+               goto open_error;
+       fd_install(file_fd, syscall_list_file);
+       return file_fd;
+
+open_error:
+       fput(syscall_list_file);
+file_error:
+       put_unused_fd(file_fd);
+fd_error:
+       return ret;
+}
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