diff --git a/headers/private/kernel/arch/thread.h b/headers/private/kernel/arch/thread.h
index 5556073300..b19066a520 100644
--- a/headers/private/kernel/arch/thread.h
+++ b/headers/private/kernel/arch/thread.h
@@ -31,12 +31,6 @@ bool arch_on_signal_stack(Thread *thread);
 status_t arch_setup_signal_frame(Thread *thread, struct sigaction *action,
 	struct signal_frame_data *signalFrameData);
 int64 arch_restore_signal_frame(struct signal_frame_data* signalFrameData);
-#ifdef _COMPAT_MODE
-status_t arch_setup_compat_signal_frame(Thread *thread,
-	struct sigaction *action, struct compat_signal_frame_data *signalFrameData);
-int64 arch_restore_compat_signal_frame(
-	struct compat_signal_frame_data* signalFrameData);
-#endif
 
 void arch_store_fork_frame(struct arch_fork_arg *arg);
 void arch_restore_fork_frame(struct arch_fork_arg *arg);
diff --git a/headers/private/kernel/arch/x86/arch_thread.h b/headers/private/kernel/arch/x86/arch_thread.h
index 2415110df8..3689d0b44b 100644
--- a/headers/private/kernel/arch/x86/arch_thread.h
+++ b/headers/private/kernel/arch/x86/arch_thread.h
@@ -51,30 +51,6 @@ arch_thread_set_current_thread(Thread* t)
 }
 
 
-#ifdef _COMPAT_MODE
-
-
-static inline void
-arch_thread_set_ds(unsigned short ds)
-{
-	asm volatile("mov %0, %%ds" : : "r" (ds) : "memory");
-}
-
-
-static inline void
-arch_thread_set_es(unsigned short es)
-{
-	asm volatile("mov %0, %%es" : : "r" (es) : "memory");
-}
-
-// override empty macro
-#undef arch_syscall_64_bit_return_value
-void arch_syscall_64_bit_return_value(void);
-
-
-#endif // _COMPAT_MODE
-
-
 #else	// __x86_64__
 
 
diff --git a/headers/private/kernel/compat/OS_compat.h b/headers/private/kernel/compat/OS_compat.h
deleted file mode 100644
index 0fbc7a952a..0000000000
--- a/headers/private/kernel/compat/OS_compat.h
+++ /dev/null
@@ -1,277 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_OS_H
-#define _KERNEL_COMPAT_OS_H
-
-
-typedef struct {
-	bigtime_t		boot_time;			/* time of boot (usecs since 1/1/1970) */
-
-	uint32			cpu_count;			/* number of cpus */
-
-	uint64			max_pages;			/* total # of accessible pages */
-	uint64			used_pages;			/* # of accessible pages in use */
-	uint64			cached_pages;
-	uint64			block_cache_pages;
-	uint64			ignored_pages;		/* # of ignored/inaccessible pages */
-
-	uint64			needed_memory;
-	uint64			free_memory;
-
-	uint64			max_swap_pages;
-	uint64			free_swap_pages;
-
-	uint32			page_faults;		/* # of page faults */
-
-	uint32			max_sems;
-	uint32			used_sems;
-
-	uint32			max_ports;
-	uint32			used_ports;
-
-	uint32			max_threads;
-	uint32			used_threads;
-
-	uint32			max_teams;
-	uint32			used_teams;
-
-	char			kernel_name[B_FILE_NAME_LENGTH];
-	char			kernel_build_date[B_OS_NAME_LENGTH];
-	char			kernel_build_time[B_OS_NAME_LENGTH];
-
-	int64			kernel_version;
-	uint32			abi;				/* the system API */
-} _PACKED compat_system_info;
-
-
-static_assert(sizeof(compat_system_info) == 0x1c4,
-	"size of compat_system_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(system_info &info, system_info* userInfo)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_system_info compat_info;
-		compat_info.boot_time = info.boot_time;
-		compat_info.cpu_count = info.cpu_count;
-		compat_info.max_pages = info.max_pages;
-		compat_info.used_pages = info.used_pages;
-		compat_info.cached_pages = info.cached_pages;
-		compat_info.block_cache_pages = info.block_cache_pages;
-		compat_info.ignored_pages = info.ignored_pages;
-		compat_info.needed_memory = info.needed_memory;
-		compat_info.free_memory = info.free_memory;
-		compat_info.needed_memory = info.needed_memory;
-		compat_info.max_swap_pages = info.max_swap_pages;
-		compat_info.free_swap_pages = info.free_swap_pages;
-		compat_info.max_sems = info.max_sems;
-		compat_info.used_sems = info.used_sems;
-		compat_info.max_ports = info.max_ports;
-		compat_info.used_ports = info.used_ports;
-		compat_info.max_threads = info.max_threads;
-		compat_info.used_threads = info.used_threads;
-		compat_info.max_teams = info.max_teams;
-		compat_info.used_teams = info.used_teams;
-		strlcpy(compat_info.kernel_name, info.kernel_name, B_FILE_NAME_LENGTH);
-		strlcpy(compat_info.kernel_build_date, info.kernel_build_date,
-			B_OS_NAME_LENGTH);
-		strlcpy(compat_info.kernel_build_time, info.kernel_build_time,
-			B_OS_NAME_LENGTH);
-		compat_info.kernel_version = info.kernel_version;
-		compat_info.abi = info.abi;
-		if (user_memcpy(userInfo, &compat_info, sizeof(compat_info)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else if (user_memcpy(userInfo, &info, sizeof(system_info)) < B_OK)
-		return B_BAD_ADDRESS;
-	return B_OK;
-}
-
-
-#define compat_size_t uint32
-#define compat_ptr_t uint32
-typedef struct compat_area_info {
-	area_id		area;
-	char		name[B_OS_NAME_LENGTH];
-	compat_size_t	size;
-	uint32		lock;
-	uint32		protection;
-	team_id		team;
-	uint32		ram_size;
-	uint32		copy_count;
-	uint32		in_count;
-	uint32		out_count;
-	compat_ptr_t	address;
-} _PACKED compat_area_info;
-
-
-static_assert(sizeof(compat_area_info) == 0x48,
-	"size of compat_area_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(area_info &info, area_info* userInfo)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_area_info compatInfo;
-		compatInfo.area = info.area;
-		strlcpy(compatInfo.name, info.name, B_OS_NAME_LENGTH);
-		compatInfo.size = info.size;
-		compatInfo.lock = info.lock;
-		compatInfo.protection = info.protection;
-		compatInfo.team = info.team;
-		compatInfo.ram_size = info.ram_size;
-		compatInfo.copy_count = info.copy_count;
-		compatInfo.in_count = info.in_count;
-		compatInfo.out_count = info.out_count;
-		compatInfo.address = (compat_ptr_t)(addr_t)info.address;
-		if (user_memcpy(userInfo, &compatInfo, sizeof(compatInfo)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else if (user_memcpy(userInfo, &info, sizeof(info)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-typedef struct {
-	thread_id		thread;
-	team_id			team;
-	char			name[B_OS_NAME_LENGTH];
-	thread_state	state;
-	int32			priority;
-	sem_id			sem;
-	bigtime_t		user_time;
-	bigtime_t		kernel_time;
-	uint32			stack_base;
-	uint32			stack_end;
-} _PACKED compat_thread_info;
-
-
-static_assert(sizeof(compat_thread_info) == 76,
-	"size of compat_thread_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(void* &addr, void** userAddr)
-{
-	if (!IS_USER_ADDRESS(userAddr))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_ptr_t compatAddr = (uint32)(addr_t)addr;
-		if (user_memcpy(userAddr, &compatAddr, sizeof(compatAddr)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else if (user_memcpy(userAddr, &addr, sizeof(addr)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(void** userAddr, void* &addr)
-{
-	if (!IS_USER_ADDRESS(userAddr))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_ptr_t compatAddr;
-		if (user_memcpy(&compatAddr, userAddr, sizeof(compatAddr)) < B_OK)
-			return B_BAD_ADDRESS;
-		addr = (void*)(addr_t)compatAddr;
-	} else if (user_memcpy(&addr, userAddr, sizeof(addr)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(addr_t &addr, addr_t* userAddr)
-{
-	if (!IS_USER_ADDRESS(userAddr))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		uint32 compatAddr = (uint32)addr;
-		if (user_memcpy(userAddr, &compatAddr, sizeof(compatAddr)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else if (user_memcpy(userAddr, &addr, sizeof(addr)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(addr_t* userAddr, addr_t &addr)
-{
-	if (!IS_USER_ADDRESS(userAddr))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		uint32 compatAddr;
-		if (user_memcpy(&compatAddr, userAddr, sizeof(compatAddr)) < B_OK)
-			return B_BAD_ADDRESS;
-		addr = (addr_t)compatAddr;
-	} else if (user_memcpy(&addr, userAddr, sizeof(addr)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(ssize_t &size, ssize_t* userSize)
-{
-	if (!IS_USER_ADDRESS(userSize))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		int32 compatSize = (int32)size;
-		if (user_memcpy(userSize, &compatSize, sizeof(compatSize)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else if (user_memcpy(userSize, &size, sizeof(size)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(ssize_t* userSize, ssize_t &size)
-{
-	if (!IS_USER_ADDRESS(userSize))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		int32 compatSize;
-		if (user_memcpy(&compatSize, userSize, sizeof(compatSize)) < B_OK)
-			return B_BAD_ADDRESS;
-		size = (ssize_t)compatSize;
-	} else if (user_memcpy(&size, userSize, sizeof(size)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_OS_H
diff --git a/headers/private/kernel/compat/arch/x86/signal_compat.h b/headers/private/kernel/compat/arch/x86/signal_compat.h
deleted file mode 100644
index 8fe645d44c..0000000000
--- a/headers/private/kernel/compat/arch/x86/signal_compat.h
+++ /dev/null
@@ -1,113 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_ARCH_SIGNAL_H
-#define _KERNEL_COMPAT_ARCH_SIGNAL_H
-
-
-typedef struct packed_fp_stack {
-	unsigned char	st0[10];
-	unsigned char	st1[10];
-	unsigned char	st2[10];
-	unsigned char	st3[10];
-	unsigned char	st4[10];
-	unsigned char	st5[10];
-	unsigned char	st6[10];
-	unsigned char	st7[10];
-} packed_fp_stack;
-
-typedef struct packed_mmx_regs {
-	unsigned char	mm0[10];
-	unsigned char	mm1[10];
-	unsigned char	mm2[10];
-	unsigned char	mm3[10];
-	unsigned char	mm4[10];
-	unsigned char	mm5[10];
-	unsigned char	mm6[10];
-	unsigned char	mm7[10];
-} packed_mmx_regs;
-
-typedef struct xmmx_regs {
-	unsigned char	xmm0[16];
-	unsigned char	xmm1[16];
-	unsigned char	xmm2[16];
-	unsigned char	xmm3[16];
-	unsigned char	xmm4[16];
-	unsigned char	xmm5[16];
-	unsigned char	xmm6[16];
-	unsigned char	xmm7[16];
-} xmmx_regs;
-
-typedef struct compat_stack_t {
-	uint32	ss_sp;
-	uint32	ss_size;
-	int		ss_flags;
-} compat_stack_t;
-
-typedef struct compat_old_extended_regs {
-	unsigned short	fp_control;
-	unsigned short	_reserved1;
-	unsigned short	fp_status;
-	unsigned short	_reserved2;
-	unsigned short	fp_tag;
-	unsigned short	_reserved3;
-	uint32	fp_eip;
-	unsigned short	fp_cs;
-	unsigned short	fp_opcode;
-	uint32	fp_datap;
-	unsigned short	fp_ds;
-	unsigned short	_reserved4;
-	union {
-		packed_fp_stack	fp;
-		packed_mmx_regs	mmx;
-	} fp_mmx;
-} compat_old_extended_regs;
-
-typedef struct compat_new_extended_regs {
-	unsigned short	fp_control;
-	unsigned short	fp_status;
-	unsigned short	fp_tag;
-	unsigned short	fp_opcode;
-	uint32	fp_eip;
-	unsigned short	fp_cs;
-	unsigned short	res_14_15;
-	uint32	fp_datap;
-	unsigned short	fp_ds;
-	unsigned short	_reserved_22_23;
-	uint32	mxcsr;
-	uint32	_reserved_28_31;
-	union {
-		fp_stack fp;
-		mmx_regs mmx;
-	} fp_mmx;
-	xmmx_regs xmmx;
-	unsigned char	_reserved_288_511[224];
-} compat_new_extended_regs;
-
-typedef struct compat_extended_regs {
-	union {
-		compat_old_extended_regs	old_format;
-		compat_new_extended_regs	new_format;
-	} state;
-	uint32	format;
-} compat_extended_regs;
-
-struct compat_vregs {
-	uint32			eip;
-	uint32			eflags;
-	uint32			eax;
-	uint32			ecx;
-	uint32			edx;
-	uint32			esp;
-	uint32			ebp;
-	uint32			_reserved_1;
-	compat_extended_regs	xregs;
-	uint32			edi;
-	uint32			esi;
-	uint32			ebx;
-};
-
-
-#endif // _KERNEL_COMPAT_ARCH_SIGNAL_H
diff --git a/headers/private/kernel/compat/fcntl_compat.h b/headers/private/kernel/compat/fcntl_compat.h
deleted file mode 100644
index 25b38e79de..0000000000
--- a/headers/private/kernel/compat/fcntl_compat.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_FCNTL_H
-#define _KERNEL_COMPAT_FCNTL_H
-
-
-#include <fcntl.h>
-
-
-struct compat_flock {
-	short	l_type;
-	short	l_whence;
-	off_t	l_start;
-	off_t	l_len;
-	pid_t	l_pid;
-} _PACKED;
-
-
-static_assert(sizeof(struct compat_flock) == 24,
-	"size of compat_flock mismatch");
-
-
-inline status_t
-copy_ref_var_from_user(struct flock* userFlock, struct flock &flock)
-{
-	if (!IS_USER_ADDRESS(userFlock))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_flock compat_flock;
-		if (user_memcpy(&compat_flock, userFlock, sizeof(compat_flock)) < B_OK)
-			return B_BAD_ADDRESS;
-		flock.l_type = compat_flock.l_type;
-		flock.l_whence = compat_flock.l_whence;
-		flock.l_start = compat_flock.l_start;
-		flock.l_len = compat_flock.l_len;
-		flock.l_pid = compat_flock.l_pid;
-	} else {
-		if (user_memcpy(&flock, userFlock, sizeof(struct flock)) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(struct flock &flock, struct flock* userFlock)
-{
-	if (!IS_USER_ADDRESS(userFlock))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_flock compat_flock;
-		compat_flock.l_type = flock.l_type;
-		compat_flock.l_whence = flock.l_whence;
-		compat_flock.l_start = flock.l_start;
-		compat_flock.l_len = flock.l_len;
-		compat_flock.l_pid = flock.l_pid;
-		if (user_memcpy(userFlock, &compat_flock, sizeof(compat_flock)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (user_memcpy(userFlock, &flock, sizeof(flock)) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_FCNTL_H
diff --git a/headers/private/kernel/compat/fs_attr_compat.h b/headers/private/kernel/compat/fs_attr_compat.h
deleted file mode 100644
index b657fb9c2e..0000000000
--- a/headers/private/kernel/compat/fs_attr_compat.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_FS_ATTR_H
-#define _KERNEL_COMPAT_FS_ATTR_H
-
-
-#include <fs_attr.h>
-
-
-struct compat_attr_info {
-	uint32	type;
-	off_t	size;
-} _PACKED;
-
-
-static_assert(sizeof(compat_attr_info) == 12,
-	"size of compat_attr_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(attr_info &info, attr_info* userInfo)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_attr_info compat_info;
-		compat_info.type = info.type;
-		compat_info.size = info.size;
-		if (user_memcpy(userInfo, &compat_info, sizeof(compat_info)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (user_memcpy(userInfo, &info, sizeof(info)) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_FS_ATTR_H
diff --git a/headers/private/kernel/compat/fs_info_compat.h b/headers/private/kernel/compat/fs_info_compat.h
deleted file mode 100644
index 67934bcb29..0000000000
--- a/headers/private/kernel/compat/fs_info_compat.h
+++ /dev/null
@@ -1,94 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_FS_INFO_H
-#define _KERNEL_COMPAT_FS_INFO_H
-
-
-#include <fs_info.h>
-
-
-typedef struct compat_fs_info {
-	dev_t	dev;								/* volume dev_t */
-	ino_t	root;								/* root ino_t */
-	uint32	flags;								/* flags (see above) */
-	off_t	block_size;							/* fundamental block size */
-	off_t	io_size;							/* optimal i/o size */
-	off_t	total_blocks;						/* total number of blocks */
-	off_t	free_blocks;						/* number of free blocks */
-	off_t	total_nodes;						/* total number of nodes */
-	off_t	free_nodes;							/* number of free nodes */
-	char	device_name[128];					/* device holding fs */
-	char	volume_name[B_FILE_NAME_LENGTH];	/* volume name */
-	char	fsh_name[B_OS_NAME_LENGTH];			/* name of fs handler */
-} _PACKED compat_fs_info;
-
-
-static_assert(sizeof(compat_fs_info) == 480,
-	"size of compat_fs_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(fs_info &info, fs_info* userInfo)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_fs_info compat_info;
-		compat_info.dev = info.dev;
-		compat_info.root = info.root;
-		compat_info.flags = info.flags;
-		compat_info.block_size = info.block_size;
-		compat_info.io_size = info.io_size;
-		compat_info.total_blocks = info.total_blocks;
-		compat_info.free_blocks = info.free_blocks;
-		compat_info.total_nodes = info.total_nodes;
-		compat_info.free_nodes = info.free_nodes;
-		strlcpy(compat_info.device_name, info.device_name, 128);
-		strlcpy(compat_info.volume_name, info.volume_name, B_FILE_NAME_LENGTH);
-		strlcpy(compat_info.fsh_name, info.fsh_name, B_OS_NAME_LENGTH);
-		if (user_memcpy(userInfo, &compat_info, sizeof(compat_info)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (user_memcpy(userInfo, &info, sizeof(info)) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(fs_info* userInfo, fs_info &info)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_fs_info compat_info;
-		if (user_memcpy(&compat_info, userInfo, sizeof(compat_info)) < B_OK)
-			return B_BAD_ADDRESS;
-		info.dev = compat_info.dev;
-		info.root = compat_info.root;
-		info.flags = compat_info.flags;
-		info.block_size = compat_info.block_size;
-		info.io_size = compat_info.io_size;
-		info.total_blocks = compat_info.total_blocks;
-		info.free_blocks = compat_info.free_blocks;
-		info.total_nodes = compat_info.total_nodes;
-		info.free_nodes = compat_info.free_nodes;
-		strlcpy(info.device_name, compat_info.device_name, 128);
-		strlcpy(info.volume_name, compat_info.volume_name, B_FILE_NAME_LENGTH);
-		strlcpy(info.fsh_name, compat_info.fsh_name, B_OS_NAME_LENGTH);
-	} else if (user_memcpy(&info, userInfo, sizeof(info)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_FS_INFO_H
diff --git a/headers/private/kernel/compat/image_compat.h b/headers/private/kernel/compat/image_compat.h
deleted file mode 100644
index eb52f03698..0000000000
--- a/headers/private/kernel/compat/image_compat.h
+++ /dev/null
@@ -1,129 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_IMAGE_H
-#define _KERNEL_COMPAT_IMAGE_H
-
-
-#include <image.h>
-
-
-#define compat_uintptr_t uint32
-typedef struct {
-	image_id	id;
-	image_type	type;
-	int32		sequence;
-	int32		init_order;
-	compat_uintptr_t	init_routine;
-	compat_uintptr_t	term_routine;
-	dev_t		device;
-	ino_t		node;
-	char		name[MAXPATHLEN];
-	compat_uintptr_t	text;
-	compat_uintptr_t	data;
-	int32		text_size;
-	int32		data_size;
-
-	/* Haiku R1 extensions */
-	int32		api_version;	/* the Haiku API version used by the image */
-	int32		abi;			/* the Haiku ABI used by the image */
-} _PACKED compat_image_info;
-
-
-typedef struct {
-	compat_image_info	basic_info;
-	int32				text_delta;
-	compat_uintptr_t	symbol_table;
-	compat_uintptr_t	symbol_hash;
-	compat_uintptr_t	string_table;
-} _PACKED compat_extended_image_info;
-
-
-static_assert(sizeof(compat_image_info) == 1084,
-	"size of compat_image_info mismatch");
-static_assert(sizeof(compat_extended_image_info) == 1100,
-	"size of compat_extended_image_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(image_info &info, image_info* userInfo, size_t size)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		if (size > sizeof(compat_image_info))
-			return B_BAD_VALUE;
-		compat_image_info compat_info;
-		compat_info.id = info.id;
-		compat_info.type = info.type;
-		compat_info.sequence = info.sequence;
-		compat_info.init_order = info.init_order;
-		compat_info.init_routine = (uint32)(addr_t)info.init_routine;
-		compat_info.term_routine = (uint32)(addr_t)info.term_routine;
-		compat_info.device = info.device;
-		compat_info.node = info.node;
-		strlcpy(compat_info.name, info.name, MAXPATHLEN);
-		compat_info.text = (uint32)(addr_t)info.text;
-		compat_info.data = (uint32)(addr_t)info.data;
-		compat_info.text_size = info.text_size;
-		compat_info.data_size = info.data_size;
-		if (user_memcpy(userInfo, &compat_info, size) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (size > sizeof(image_info))
-			return B_BAD_VALUE;
-
-		if (user_memcpy(userInfo, &info, size) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(extended_image_info* userInfo,
-	extended_image_info &info, size_t size)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_extended_image_info compat_info;
-		if (size != sizeof(compat_info))
-			return B_BAD_VALUE;
-		if (user_memcpy(&compat_info, userInfo, size) < B_OK)
-			return B_BAD_ADDRESS;
-		info.basic_info.id = compat_info.basic_info.id;
-		info.basic_info.type = compat_info.basic_info.type;
-		info.basic_info.sequence = compat_info.basic_info.sequence;
-		info.basic_info.init_order = compat_info.basic_info.init_order;
-		info.basic_info.init_routine = (void(*)())(addr_t)compat_info.basic_info.init_routine;
-		info.basic_info.term_routine = (void(*)())(addr_t)compat_info.basic_info.term_routine;
-		info.basic_info.device = compat_info.basic_info.device;
-		info.basic_info.node = compat_info.basic_info.node;
-		strlcpy(info.basic_info.name, compat_info.basic_info.name, MAXPATHLEN);
-		info.basic_info.text = (void*)(addr_t)compat_info.basic_info.text;
-		info.basic_info.data = (void*)(addr_t)compat_info.basic_info.data;
-		info.basic_info.text_size = compat_info.basic_info.text_size;
-		info.basic_info.data_size = compat_info.basic_info.data_size;
-		info.text_delta = compat_info.text_delta;
-		info.symbol_table = (void*)(addr_t)compat_info.symbol_table;
-		info.symbol_hash = (void*)(addr_t)compat_info.symbol_hash;
-		info.string_table = (void*)(addr_t)compat_info.string_table;
-	} else {
-		if (size != sizeof(info))
-			return B_BAD_VALUE;
-
-		if (user_memcpy(&info, userInfo, size) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_IMAGE_H
diff --git a/headers/private/kernel/compat/ksignal_compat.h b/headers/private/kernel/compat/ksignal_compat.h
deleted file mode 100644
index d193e08dc5..0000000000
--- a/headers/private/kernel/compat/ksignal_compat.h
+++ /dev/null
@@ -1,165 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_KSIGNAL_H
-#define _KERNEL_COMPAT_KSIGNAL_H
-
-
-#include <compat/signal_compat.h>
-#include <compat/arch/x86/signal_compat.h>
-
-
-typedef struct compat_vregs compat_mcontext_t;
-
-typedef struct __compat_ucontext_t {
-	uint32					uc_link;
-	sigset_t				uc_sigmask;
-	compat_stack_t			uc_stack;
-	compat_mcontext_t		uc_mcontext;
-} _PACKED compat_ucontext_t;
-
-union compat_sigval {
-	int		sival_int;
-	uint32	sival_ptr;
-};
-
-
-typedef struct __compat_siginfo_t {
-	int				si_signo;	/* signal number */
-	int				si_code;	/* signal code */
-	int				si_errno;	/* if non zero, an error number associated with
-								   this signal */
-	pid_t			si_pid;		/* sending process ID */
-	uid_t			si_uid;		/* real user ID of sending process */
-	uint32			si_addr;	/* address of faulting instruction */
-	int				si_status;	/* exit value or signal */
-	uint32			si_band;	/* band event for SIGPOLL */
-	union compat_sigval	si_value;	/* signal value */
-} compat_siginfo_t;
-
-
-struct compat_signal_frame_data {
-	compat_siginfo_t	info;
-	compat_ucontext_t	context;
-	uint32		user_data;
-	uint32		handler;
-	bool		siginfo_handler;
-	char		_pad[3];
-	int32		thread_flags;
-	uint64		syscall_restart_return_value;
-	uint8		syscall_restart_parameters[SYSCALL_RESTART_PARAMETER_SIZE];
-	uint32		commpage_address;
-} _PACKED;
-
-
-static_assert(sizeof(compat_stack_t) == 12,
-	"size of compat_stack_t mismatch");
-static_assert(sizeof(compat_mcontext_t) == 560,
-	"size of compat_mcontext_t mismatch");
-static_assert(sizeof(compat_ucontext_t) == 584,
-	"size of compat_ucontext_t mismatch");
-static_assert(sizeof(compat_siginfo_t) == 36,
-	"size of compat_siginfo_t mismatch");
-static_assert(sizeof(struct compat_signal_frame_data) == 680,
-	"size of compat_signal_frame_data mismatch");
-
-
-inline status_t
-copy_ref_var_from_user(union sigval* userSigval, union sigval &sigval)
-{
-	if (!IS_USER_ADDRESS(userSigval))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_sigval compat_sigval;
-		if (user_memcpy(&compat_sigval, userSigval, sizeof(compat_sigval))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-		sigval.sival_ptr = (void*)(addr_t)compat_sigval.sival_ptr;
-	} else if (user_memcpy(&sigval, userSigval, sizeof(union sigval)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(siginfo_t &info, siginfo_t* userInfo)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_siginfo_t compat_info;
-		compat_info.si_signo = info.si_signo;
-		compat_info.si_code = info.si_code;
-		compat_info.si_errno = info.si_errno;
-		compat_info.si_pid = info.si_pid;
-		compat_info.si_uid = info.si_uid;
-		compat_info.si_addr = (addr_t)info.si_addr;
-		compat_info.si_status = info.si_status;
-		compat_info.si_band = info.si_band;
-		compat_info.si_value.sival_ptr = (addr_t)info.si_value.sival_ptr;
-		if (user_memcpy(userInfo, &compat_info, sizeof(compat_info))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-	} else if (user_memcpy(userInfo, &info, sizeof(info)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(stack_t* userStack, stack_t &stack)
-{
-	if (!IS_USER_ADDRESS(userStack))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_stack_t compatStack;
-		if (user_memcpy(&compatStack, userStack, sizeof(compatStack))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-		stack.ss_sp = (void*)(addr_t)compatStack.ss_sp;
-		stack.ss_size = compatStack.ss_size;
-		stack.ss_flags = compatStack.ss_flags;
-	} else if (user_memcpy(&stack, userStack, sizeof(stack_t)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(stack_t &stack, stack_t* userStack)
-{
-	if (!IS_USER_ADDRESS(userStack))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		compat_stack_t compatStack;
-		compatStack.ss_sp = (addr_t)stack.ss_sp;
-		compatStack.ss_size = stack.ss_size;
-		compatStack.ss_flags = stack.ss_flags;
-		if (user_memcpy(userStack, &compatStack, sizeof(compatStack))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-	} else if (user_memcpy(userStack, &stack, sizeof(stack)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_KSIGNAL_H
diff --git a/headers/private/kernel/compat/signal_compat.h b/headers/private/kernel/compat/signal_compat.h
deleted file mode 100644
index c81865f3f6..0000000000
--- a/headers/private/kernel/compat/signal_compat.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_SIGNAL_H
-#define _KERNEL_COMPAT_SIGNAL_H
-
-
-struct compat_sigaction {
-	union {
-		uint32		sa_handler;
-		uint32		sa_sigaction;
-	};
-	sigset_t				sa_mask;
-	int						sa_flags;
-	uint32					sa_userdata;	/* will be passed to the signal
-											   handler, BeOS extension */
-} _PACKED;
-
-
-inline status_t
-copy_ref_var_from_user(struct sigaction* userAction, struct sigaction &action)
-{
-	if (!IS_USER_ADDRESS(userAction))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		struct compat_sigaction compat_action;
-		if (user_memcpy(&compat_action, userAction, sizeof(compat_sigaction))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-		action.sa_handler = (__sighandler_t)(addr_t)compat_action.sa_handler;
-		action.sa_mask = compat_action.sa_mask;
-		action.sa_flags = compat_action.sa_flags;
-		action.sa_userdata = (void*)(addr_t)compat_action.sa_userdata;
-	} else if (user_memcpy(&action, userAction, sizeof(action)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(struct sigaction &action, struct sigaction* userAction)
-{
-	if (!IS_USER_ADDRESS(userAction))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		struct compat_sigaction compat_action;
-		compat_action.sa_handler = (addr_t)action.sa_handler;
-		compat_action.sa_mask = action.sa_mask;
-		compat_action.sa_flags = action.sa_flags;
-		compat_action.sa_userdata = (addr_t)action.sa_userdata;
-		if (user_memcpy(userAction, &compat_action, sizeof(compat_action))
-				< B_OK) {
-			return B_BAD_ADDRESS;
-		}
-	} else if (user_memcpy(userAction, &action, sizeof(action)) < B_OK) {
-		return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_SIGNAL_H
diff --git a/headers/private/kernel/compat/stat_compat.h b/headers/private/kernel/compat/stat_compat.h
deleted file mode 100644
index 08f487a676..0000000000
--- a/headers/private/kernel/compat/stat_compat.h
+++ /dev/null
@@ -1,117 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_STAT_H
-#define _KERNEL_COMPAT_STAT_H
-
-
-#include <sys/stat.h>
-#include <time_compat.h>
-
-
-struct compat_stat {
-	dev_t			st_dev;			/* device ID that this file resides on */
-	ino_t			st_ino;			/* this file's serial inode ID */
-	mode_t			st_mode;		/* file mode (rwx for user, group, etc) */
-	nlink_t			st_nlink;		/* number of hard links to this file */
-	uid_t			st_uid;			/* user ID of the owner of this file */
-	gid_t			st_gid;			/* group ID of the owner of this file */
-	off_t			st_size;		/* size in bytes of this file */
-	dev_t			st_rdev;		/* device type (not used) */
-	blksize_t		st_blksize;		/* preferred block size for I/O */
-	struct compat_timespec	st_atim;		/* last access time */
-	struct compat_timespec	st_mtim;		/* last modification time */
-	struct compat_timespec	st_ctim;		/* last change time, not creation time */
-	struct compat_timespec	st_crtim;		/* creation time */
-	__haiku_uint32	st_type;		/* attribute/index type */
-	blkcnt_t		st_blocks;		/* number of blocks allocated for object */
-} _PACKED;
-
-
-static_assert(sizeof(struct compat_stat) == 88,
-	"size of struct compat_stat mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(struct stat &stat, struct stat* userStat, size_t size)
-{
-	if (!IS_USER_ADDRESS(userStat))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		if (size > sizeof(compat_stat))
-			return B_BAD_VALUE;
-		struct compat_stat compat_stat;
-		compat_stat.st_dev = stat.st_dev;
-		compat_stat.st_ino = stat.st_ino;
-		compat_stat.st_mode = stat.st_mode;
-		compat_stat.st_nlink = stat.st_nlink;
-		compat_stat.st_uid = stat.st_gid;
-		compat_stat.st_size = stat.st_size;
-		compat_stat.st_rdev = stat.st_rdev;
-		compat_stat.st_blksize = stat.st_blksize;
-		compat_stat.st_atim.tv_sec = stat.st_atim.tv_sec;
-		compat_stat.st_atim.tv_nsec = stat.st_atim.tv_nsec;
-		compat_stat.st_mtim.tv_sec = stat.st_mtim.tv_sec;
-		compat_stat.st_mtim.tv_nsec = stat.st_mtim.tv_nsec;
-		compat_stat.st_ctim.tv_sec = stat.st_ctim.tv_sec;
-		compat_stat.st_ctim.tv_nsec = stat.st_ctim.tv_nsec;
-		compat_stat.st_crtim.tv_sec = stat.st_crtim.tv_sec;
-		compat_stat.st_crtim.tv_nsec = stat.st_crtim.tv_nsec;
-		compat_stat.st_type = stat.st_type;
-		compat_stat.st_blocks = stat.st_blocks;
-		if (user_memcpy(userStat, &compat_stat, size) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (size > sizeof(struct stat))
-			return B_BAD_VALUE;
-
-		if (user_memcpy(userStat, &stat, size) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_to_user(struct stat &stat, struct stat* userStat)
-{
-	if (!IS_USER_ADDRESS(userStat))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		struct compat_stat compat_stat;
-		compat_stat.st_dev = stat.st_dev;
-		compat_stat.st_ino = stat.st_ino;
-		compat_stat.st_mode = stat.st_mode;
-		compat_stat.st_nlink = stat.st_nlink;
-		compat_stat.st_uid = stat.st_gid;
-		compat_stat.st_size = stat.st_size;
-		compat_stat.st_rdev = stat.st_rdev;
-		compat_stat.st_blksize = stat.st_blksize;
-		compat_stat.st_atim.tv_sec = stat.st_atim.tv_sec;
-		compat_stat.st_atim.tv_nsec = stat.st_atim.tv_nsec;
-		compat_stat.st_mtim.tv_sec = stat.st_mtim.tv_sec;
-		compat_stat.st_mtim.tv_nsec = stat.st_mtim.tv_nsec;
-		compat_stat.st_ctim.tv_sec = stat.st_ctim.tv_sec;
-		compat_stat.st_ctim.tv_nsec = stat.st_ctim.tv_nsec;
-		compat_stat.st_crtim.tv_sec = stat.st_crtim.tv_sec;
-		compat_stat.st_crtim.tv_nsec = stat.st_crtim.tv_nsec;
-		compat_stat.st_type = stat.st_type;
-		compat_stat.st_blocks = stat.st_blocks;
-		if (user_memcpy(userStat, &compat_stat, sizeof(compat_stat)) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (user_memcpy(userStat, &stat, sizeof(stat)) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-
-#endif // _KERNEL_COMPAT_STAT_H
diff --git a/headers/private/kernel/compat/time_compat.h b/headers/private/kernel/compat/time_compat.h
deleted file mode 100644
index 819a79d074..0000000000
--- a/headers/private/kernel/compat/time_compat.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_TIME_H
-#define _KERNEL_COMPAT_TIME_H
-
-
-#include <time.h>
-
-
-struct compat_timespec {
-	uint32	tv_sec;			/* seconds */
-	uint32	tv_nsec;		/* and nanoseconds */
-};
-
-
-#endif // _KERNEL_COMPAT_TIME_H
diff --git a/headers/private/kernel/compat/vfs_defs_compat.h b/headers/private/kernel/compat/vfs_defs_compat.h
deleted file mode 100644
index 05a79ba1cd..0000000000
--- a/headers/private/kernel/compat/vfs_defs_compat.h
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright 2018, Haiku Inc. All rights reserved.
- *
- * Distributed under the terms of the MIT License.
- */
-#ifndef _KERNEL_COMPAT_VFS_DEFS_H
-#define _KERNEL_COMPAT_VFS_DEFS_H
-
-
-#include <vfs_defs.h>
-
-
-struct compat_fd_info {
-	int		number;
-	int32	open_mode;
-	dev_t	device;
-	ino_t	node;
-} _PACKED;
-
-
-static_assert(sizeof(compat_fd_info) == 20,
-	"size of compat_fd_info mismatch");
-
-
-inline status_t
-copy_ref_var_to_user(attr_info &info, attr_info* userInfo, size_t size)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		if (size != sizeof(compat_fd_info))
-			return B_BAD_VALUE;
-		compat_fd_info compat_info;
-		compat_info.number = info.number;
-		compat_info.open_mode = info.open_mode;
-		compat_info.device = info.device;
-		compat_info.node = info.node;
-		if (user_memcpy(userInfo, &compat_info, size) < B_OK)
-			return B_BAD_ADDRESS;
-	} else {
-		if (size != sizeof(fd_info))
-			return B_BAD_VALUE;
-		if (user_memcpy(userInfo, &info, size) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-inline status_t
-copy_ref_var_from_user(fd_info* userInfo, fd_info &info, size_t size)
-{
-	if (!IS_USER_ADDRESS(userInfo))
-		return B_BAD_ADDRESS;
-	Thread* thread = thread_get_current_thread();
-	bool compatMode = (thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0;
-	if (compatMode) {
-		if (size != sizeof(compat_fd_info))
-			return B_BAD_VALUE;
-		compat_fd_info compat_info;
-		if (user_memcpy(&compat_info, userInfo, size) < B_OK)
-			return B_BAD_ADDRESS;
-		info.number = compat_info.number;
-		info.open_mode = compat_info.open_mode;
-		info.device = compat_info.device;
-		info.node = compat_info.node;
-	} else {
-		if (size != sizeof(fd_info))
-			return B_BAD_VALUE;
-		if (user_memcpy(&info, userInfo, size) < B_OK)
-			return B_BAD_ADDRESS;
-	}
-	return B_OK;
-}
-
-
-#endif // _KERNEL_COMPAT_VFS_DEFS_H
diff --git a/headers/private/kernel/util/syscall_args.h b/headers/private/kernel/util/syscall_args.h
index c6d1d6166d..46eab7342c 100644
--- a/headers/private/kernel/util/syscall_args.h
+++ b/headers/private/kernel/util/syscall_args.h
@@ -23,18 +23,6 @@ copy_ref_var_from_user(T *user, T &kernel)
 	return user_memcpy(&kernel, user, sizeof(T));
 }
 
-
-template<typename T>
-inline
-status_t
-copy_ref_var_from_user(T *user, T &kernel, size_t size)
-{
-	if (size != sizeof(T))
-		return B_BAD_VALUE;
-	return copy_ref_var_from_user(user, kernel);
-}
-
-
 // copy_ref_var_to_user
 template<typename T>
 inline
@@ -47,17 +35,4 @@ copy_ref_var_to_user(T &kernel, T *user)
 }
 
 
-template<typename T>
-inline
-status_t
-copy_ref_var_to_user(T &kernel, T *user, size_t size)
-{
-	if (size > sizeof(T))
-		return B_BAD_VALUE;
-	if (!IS_USER_ADDRESS(user))
-		return B_BAD_ADDRESS;
-	return user_memcpy(user, &kernel, size);
-}
-
-
 #endif	// _SYSCALL_ARGS_H
diff --git a/src/system/kernel/arch/x86/64/thread.cpp b/src/system/kernel/arch/x86/64/thread.cpp
index 7a6a35d724..a29697a03f 100644
--- a/src/system/kernel/arch/x86/64/thread.cpp
+++ b/src/system/kernel/arch/x86/64/thread.cpp
@@ -18,9 +18,6 @@
 #include <debug.h>
 #include <kernel.h>
 #include <ksignal.h>
-#ifdef _COMPAT_MODE
-#	include <compat/ksignal_compat.h>
-#endif
 #include <int.h>
 #include <team.h>
 #include <thread.h>
@@ -91,33 +88,11 @@ x86_restart_syscall(iframe* frame)
 }
 
 
-#ifdef _COMPAT_MODE
-
-
-static inline void
-set_fs_register(uint32 segment)
-{
-	asm("movl %0,%%fs" :: "r" (segment));
-}
-
-
-#endif // _COMPAT_MODE
-
-
 void
 x86_set_tls_context(Thread* thread)
 {
-#ifdef _COMPAT_MODE
-	if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0) {
-		unsigned index = x86_64_set_user_tls_segment_base(
-			smp_get_current_cpu(), thread->user_local_storage);
-		set_fs_register((index << 3) | DPL_USER);
-	} else
-#endif
-	{
-		// Set FS segment base address to the TLS segment.
-		x86_write_msr(IA32_MSR_FS_BASE, thread->user_local_storage);
-	}
+	// Set FS segment base address to the TLS segment.
+	x86_write_msr(IA32_MSR_FS_BASE, thread->user_local_storage);
 }
 
 
@@ -134,24 +109,6 @@ arch_randomize_stack_pointer(addr_t value)
 }
 
 
-#ifdef _COMPAT_MODE
-
-
-static addr_t
-arch_compat_randomize_stack_pointer(addr_t value)
-{
-	STATIC_ASSERT(MAX_RANDOM_VALUE >= B_PAGE_SIZE - 1);
-	value -= random_value() & (B_PAGE_SIZE - 1);
-	return (value & ~addr_t(0xf)) - 4;
-		// This means, result % 16 == 12, which is what esp should adhere to
-		// when a function is entered for the stack to be considered aligned to
-		// 16 byte.
-}
-
-
-#endif // _COMPAT_MODE
-
-
 static uint8*
 get_signal_stack(Thread* thread, iframe* frame, struct sigaction* action,
 	size_t spaceNeeded)
@@ -261,55 +218,27 @@ arch_thread_enter_userspace(Thread* thread, addr_t entry, void* args1,
 	TRACE("arch_thread_enter_userspace: entry %#lx, args %p %p, "
 		"stackTop %#lx\n", entry, args1, args2, stackTop);
 
+	stackTop = arch_randomize_stack_pointer(stackTop - sizeof(codeAddr));
+
 	// Copy the address of the stub that calls exit_thread() when the thread
 	// entry function returns to the top of the stack to act as the return
 	// address. The stub is inside commpage.
 	addr_t commPageAddress = (addr_t)thread->team->commpage_address;
-
-#ifdef _COMPAT_MODE
-	if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0) {
-		uint32 args[3];
-		stackTop = arch_compat_randomize_stack_pointer(stackTop - sizeof(args));
-
-		set_ac();
-		args[0] = ((addr_t*)commPageAddress)[COMMPAGE_ENTRY_X86_THREAD_EXIT]
-			+ commPageAddress;
-		clear_ac();
-		args[1] = (uint32)(addr_t)args1;
-		args[2] = (uint32)(addr_t)args2;
-		if (user_memcpy((void *)stackTop, args, sizeof(args)) < B_OK)
-			return B_BAD_ADDRESS;
-
-	} else
-#endif
-	{
-		stackTop = arch_randomize_stack_pointer(stackTop - sizeof(codeAddr));
-
-		set_ac();
-		codeAddr = ((addr_t*)commPageAddress)[COMMPAGE_ENTRY_X86_THREAD_EXIT]
-			+ commPageAddress;
-		clear_ac();
-		if (user_memcpy((void*)stackTop, (const void*)&codeAddr, sizeof(codeAddr))
+	set_ac();
+	codeAddr = ((addr_t*)commPageAddress)[COMMPAGE_ENTRY_X86_THREAD_EXIT]
+		+ commPageAddress;
+	clear_ac();
+	if (user_memcpy((void*)stackTop, (const void*)&codeAddr, sizeof(codeAddr))
 			!= B_OK)
-			return B_BAD_ADDRESS;
-	}
+		return B_BAD_ADDRESS;
 
 	// Prepare the user iframe.
 	iframe frame = {};
 	frame.type = IFRAME_TYPE_SYSCALL;
+	frame.si = (uint64)args2;
+	frame.di = (uint64)args1;
 	frame.ip = entry;
-#ifdef _COMPAT_MODE
-	if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0) {
-		frame.cs = USER32_CODE_SELECTOR;
-		arch_thread_set_ds(USER_DATA_SELECTOR);
-		arch_thread_set_es(USER_DATA_SELECTOR);
-	} else
-#endif
-	{
-		frame.si = (uint64)args2;
-		frame.di = (uint64)args1;
-		frame.cs = USER_CODE_SELECTOR;
-	}
+	frame.cs = USER_CODE_SELECTOR;
 	frame.flags = X86_EFLAGS_RESERVED1 | X86_EFLAGS_INTERRUPT
 		| (3 << X86_EFLAGS_IO_PRIVILEG_LEVEL_SHIFT);
 	frame.sp = stackTop;
@@ -465,120 +394,3 @@ arch_restore_signal_frame(struct signal_frame_data* signalFrameData)
 	// restored.
 	return frame->ax;
 }
-
-
-#ifdef _COMPAT_MODE
-
-status_t
-arch_setup_compat_signal_frame(Thread* thread, struct sigaction* action,
-	struct compat_signal_frame_data* signalFrameData)
-{
-	iframe* frame = x86_get_current_iframe();
-	if (!IFRAME_IS_USER(frame)) {
-		panic("arch_setup_compat_signal_frame(): No user iframe!");
-		return B_BAD_VALUE;
-	}
-
-	// Store the register state.
-	signalFrameData->context.uc_mcontext.eax = frame->ax;
-	signalFrameData->context.uc_mcontext.ebx = frame->bx;
-	signalFrameData->context.uc_mcontext.ecx = frame->cx;
-	signalFrameData->context.uc_mcontext.edx = frame->dx;
-	signalFrameData->context.uc_mcontext.edi = frame->di;
-	signalFrameData->context.uc_mcontext.esi = frame->si;
-	signalFrameData->context.uc_mcontext.ebp = frame->bp;
-	signalFrameData->context.uc_mcontext.esp = frame->user_sp;
-	signalFrameData->context.uc_mcontext.eip = frame->ip;
-	signalFrameData->context.uc_mcontext.eflags = frame->flags;
-	x86_fnsave((void *)(&signalFrameData->context.uc_mcontext.xregs));
-
-	// Fill in signalFrameData->context.uc_stack.
-	stack_t stack;
-	signal_get_user_stack(frame->user_sp, &stack);
-	signalFrameData->context.uc_stack.ss_sp = (addr_t)stack.ss_sp;
-	signalFrameData->context.uc_stack.ss_size = stack.ss_size;
-	signalFrameData->context.uc_stack.ss_flags = stack.ss_flags;
-
-	// Store syscall_restart_return_value.
-	signalFrameData->syscall_restart_return_value = frame->orig_rax;
-
-	// Get the stack to use and copy the frame data to it.
-	uint32 stackFrame[2];
-	uint8* userStack = get_signal_stack(thread, frame, action,
-		sizeof(*signalFrameData) + sizeof(stackFrame));
-
-	compat_signal_frame_data* userSignalFrameData
-		= (compat_signal_frame_data*)(userStack + sizeof(stackFrame));
-
-	if (user_memcpy(userSignalFrameData, signalFrameData,
-			sizeof(*signalFrameData)) != B_OK) {
-		return B_BAD_ADDRESS;
-	}
-
-	// prepare the user stack frame for a function call to the signal handler
-	// wrapper function
-	stackFrame[0] = frame->ip;
-	stackFrame[1] = (addr_t)userSignalFrameData;
-		// parameter: pointer to signal frame data
-
-	if (user_memcpy(userStack, stackFrame, sizeof(stackFrame)) != B_OK)
-		return B_BAD_ADDRESS;
-
-	// Update Thread::user_signal_context, now that everything seems to have
-	// gone fine.
-	thread->user_signal_context = (ucontext_t*)&userSignalFrameData->context;
-
-	// Set up the iframe to execute the signal handler wrapper on our prepared
-	// stack. First argument points to the frame data.
-	addr_t* commPageAddress = (addr_t*)thread->team->commpage_address;
-	frame->user_sp = (addr_t)userStack;
-	set_ac();
-
-	// from x86/arch_commpage_defs.h
-#define COMPAT_COMMPAGE_ENTRY_X86_SIGNAL_HANDLER \
-	(COMMPAGE_ENTRY_FIRST_ARCH_SPECIFIC + 3)
-	frame->ip = commPageAddress[COMPAT_COMMPAGE_ENTRY_X86_SIGNAL_HANDLER]
-		+ (addr_t)commPageAddress;
-	clear_ac();
-
-	return B_OK;
-}
-
-
-int64
-arch_restore_compat_signal_frame(struct compat_signal_frame_data* signalFrameData)
-{
-	iframe* frame = x86_get_current_iframe();
-
-	frame->orig_rax = signalFrameData->syscall_restart_return_value;
-	frame->ax = signalFrameData->context.uc_mcontext.eax;
-	frame->bx = signalFrameData->context.uc_mcontext.ebx;
-	frame->cx = signalFrameData->context.uc_mcontext.ecx;
-	frame->dx = signalFrameData->context.uc_mcontext.edx;
-	frame->di = signalFrameData->context.uc_mcontext.edi;
-	frame->si = signalFrameData->context.uc_mcontext.esi;
-	frame->bp = signalFrameData->context.uc_mcontext.ebp;
-	frame->user_sp = signalFrameData->context.uc_mcontext.esp;
-	frame->ip = signalFrameData->context.uc_mcontext.eip;
-	frame->flags = (frame->flags & ~(uint64)X86_EFLAGS_USER_FLAGS)
-		| (signalFrameData->context.uc_mcontext.eflags & X86_EFLAGS_USER_FLAGS);
-
-	x86_frstor((void*)(&signalFrameData->context.uc_mcontext.xregs));
-
-	// The syscall return code overwrites frame->ax with the return value of
-	// the syscall, need to return it here to ensure the correct value is
-	// restored.
-	return frame->ax;
-}
-
-
-void
-arch_syscall_64_bit_return_value(void)
-{
-	Thread* thread = thread_get_current_thread();
-	if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0)
-		atomic_or(&thread->flags, THREAD_FLAGS_64_BIT_SYSCALL_RETURN);
-}
-
-#endif // _COMPAT_MODE
-
diff --git a/src/system/kernel/fs/vfs.cpp b/src/system/kernel/fs/vfs.cpp
index 192ecd1210..4f1657a55c 100644
--- a/src/system/kernel/fs/vfs.cpp
+++ b/src/system/kernel/fs/vfs.cpp
@@ -49,19 +49,11 @@
 #include <util/atomic.h>
 #include <util/AutoLock.h>
 #include <util/DoublyLinkedList.h>
-#include <util/syscall_args.h>
 #include <vfs.h>
 #include <vm/vm.h>
 #include <vm/VMCache.h>
 #include <wait_for_objects.h>
 
-#ifdef _COMPAT_MODE
-#	include <fcntl_compat.h>
-#	include <stat_compat.h>
-#	include <fs_attr_compat.h>
-#	include <fs_info_compat.h>
-#endif
-
 #include "EntryCache.h"
 #include "fifo.h"
 #include "IORequest.h"
@@ -6124,8 +6116,10 @@ common_fcntl(int fd, int op, size_t argument, bool kernel)
 	if (op == F_SETLK || op == F_SETLKW || op == F_GETLK) {
 		if (descriptor->type != FDTYPE_FILE)
 			status = B_BAD_VALUE;
-		else
-			status = copy_ref_var_from_user((struct flock*)argument, flock);
+		else if (user_memcpy(&flock, (struct flock*)argument,
+				sizeof(struct flock)) != B_OK)
+			status = B_BAD_ADDRESS;
+
 		if (status != B_OK) {
 			put_fd(descriptor);
 			return status;
@@ -8804,7 +8798,10 @@ _user_read_fs_info(dev_t device, struct fs_info* userInfo)
 	if (status != B_OK)
 		return status;
 
-	return copy_ref_var_to_user(info, userInfo);
+	if (user_memcpy(userInfo, &info, sizeof(struct fs_info)) != B_OK)
+		return B_BAD_ADDRESS;
+
+	return B_OK;
 }
 
 
@@ -8816,9 +8813,9 @@ _user_write_fs_info(dev_t device, const struct fs_info* userInfo, int mask)
 	if (userInfo == NULL)
 		return B_BAD_VALUE;
 
-	status_t status = copy_ref_var_from_user((struct fs_info*)userInfo, info);
-	if (status != B_OK)
-		return status;
+	if (!IS_USER_ADDRESS(userInfo)
+		|| user_memcpy(&info, userInfo, sizeof(struct fs_info)) != B_OK)
+		return B_BAD_ADDRESS;
 
 	return fs_write_info(device, &info, mask);
 }
@@ -8864,6 +8861,9 @@ _user_get_next_fd_info(team_id team, uint32* userCookie, fd_info* userInfo,
 	if (geteuid() != 0)
 		return B_NOT_ALLOWED;
 
+	if (infoSize != sizeof(fd_info))
+		return B_BAD_VALUE;
+
 	if (!IS_USER_ADDRESS(userCookie) || !IS_USER_ADDRESS(userInfo)
 		|| user_memcpy(&cookie, userCookie, sizeof(uint32)) != B_OK)
 		return B_BAD_ADDRESS;
@@ -8872,9 +8872,11 @@ _user_get_next_fd_info(team_id team, uint32* userCookie, fd_info* userInfo,
 	if (status != B_OK)
 		return status;
 
-	if (user_memcpy(userCookie, &cookie, sizeof(uint32)) != B_OK)
+	if (user_memcpy(userCookie, &cookie, sizeof(uint32)) != B_OK
+		|| user_memcpy(userInfo, &info, infoSize) != B_OK)
 		return B_BAD_ADDRESS;
-	return copy_ref_var_to_user(info, userInfo);
+
+	return status;
 }
 
 
@@ -9525,7 +9527,7 @@ _user_read_stat(int fd, const char* userPath, bool traverseLink,
 	if (status != B_OK)
 		return status;
 
-	return copy_ref_var_to_user(stat, userStat, statSize);
+	return user_memcpy(userStat, &stat, statSize);
 }
 
 
@@ -9696,7 +9698,8 @@ _user_stat_attr(int fd, const char* userAttribute,
 		info.type = stat.st_type;
 		info.size = stat.st_size;
 
-		status = copy_ref_var_to_user(info, userAttrInfo);
+		if (user_memcpy(userAttrInfo, &info, sizeof(struct attr_info)) != B_OK)
+			return B_BAD_ADDRESS;
 	}
 
 	return status;
@@ -9805,8 +9808,10 @@ _user_read_index_stat(dev_t device, const char* userName, struct stat* userStat)
 		return B_BAD_ADDRESS;
 
 	status = index_name_read_stat(device, name, &stat, false);
-	if (status == B_OK)
-		status = copy_ref_var_to_user(stat, userStat);
+	if (status == B_OK) {
+		if (user_memcpy(userStat, &stat, sizeof(stat)) != B_OK)
+			return B_BAD_ADDRESS;
+	}
 
 	return status;
 }
diff --git a/src/system/kernel/image.cpp b/src/system/kernel/image.cpp
index 41b79899f4..30c4b293b0 100644
--- a/src/system/kernel/image.cpp
+++ b/src/system/kernel/image.cpp
@@ -18,11 +18,6 @@
 #include <thread_types.h>
 #include <user_debugger.h>
 #include <util/AutoLock.h>
-#include <util/syscall_args.h>
-
-#ifdef _COMPAT_MODE
-#	include <image_compat.h>
-#endif
 
 #include <stdlib.h>
 #include <string.h>
@@ -469,9 +464,12 @@ _user_register_image(extended_image_info *userInfo, size_t size)
 {
 	extended_image_info info;
 
-	status_t status = copy_ref_var_from_user(userInfo, info, size);
-	if (status != B_OK)
-		return status;
+	if (size != sizeof(info))
+		return B_BAD_VALUE;
+
+	if (!IS_USER_ADDRESS(userInfo)
+		|| user_memcpy(&info, userInfo, size) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return register_image(thread_get_current_thread()->team, &info, size);
 }
@@ -527,9 +525,9 @@ _user_get_image_info(image_id id, image_info *userInfo, size_t size)
 
 	status = _get_image_info(id, &info, sizeof(image_info));
 
-	status_t err = copy_ref_var_to_user(info, userInfo, size);
-	if (err != B_OK)
-		return err;
+	if (user_memcpy(userInfo, &info, size) < B_OK)
+		return B_BAD_ADDRESS;
+
 	return status;
 }
 
@@ -542,6 +540,9 @@ _user_get_next_image_info(team_id team, int32 *_cookie, image_info *userInfo,
 	status_t status;
 	int32 cookie;
 
+	if (size > sizeof(image_info))
+		return B_BAD_VALUE;
+
 	if (!IS_USER_ADDRESS(userInfo) || !IS_USER_ADDRESS(_cookie)
 		|| user_memcpy(&cookie, _cookie, sizeof(int32)) < B_OK) {
 		return B_BAD_ADDRESS;
@@ -549,11 +550,10 @@ _user_get_next_image_info(team_id team, int32 *_cookie, image_info *userInfo,
 
 	status = _get_next_image_info(team, &cookie, &info, sizeof(image_info));
 
-	status_t err = copy_ref_var_to_user(info, userInfo, size);
-	if (err != B_OK)
-		return err;
-	if (user_memcpy(_cookie, &cookie, sizeof(int32)) < B_OK)
+	if (user_memcpy(userInfo, &info, size) < B_OK
+		|| user_memcpy(_cookie, &cookie, sizeof(int32)) < B_OK) {
 		return B_BAD_ADDRESS;
+	}
 
 	return status;
 }
diff --git a/src/system/kernel/signal.cpp b/src/system/kernel/signal.cpp
index f0a671028b..cea1c3168e 100644
--- a/src/system/kernel/signal.cpp
+++ b/src/system/kernel/signal.cpp
@@ -35,11 +35,6 @@
 #include <user_debugger.h>
 #include <user_thread.h>
 #include <util/AutoLock.h>
-#include <util/syscall_args.h>
-
-#ifdef _COMPAT_MODE
-#	include <compat/ksignal_compat.h>
-#endif
 
 
 //#define TRACE_SIGNAL
@@ -913,61 +908,6 @@ setup_signal_frame(Thread* thread, struct sigaction* action, Signal* signal,
 }
 
 
-#ifdef _COMPAT_MODE
-
-static status_t
-setup_compat_signal_frame(Thread* thread, struct sigaction* action, Signal* signal,
-	sigset_t signalMask)
-{
-	// prepare the data, we need to copy onto the user stack
-	struct compat_signal_frame_data frameData;
-
-	// signal info
-	frameData.info.si_signo = signal->Number();
-	frameData.info.si_code = signal->SignalCode();
-	frameData.info.si_errno = signal->ErrorCode();
-	frameData.info.si_pid = signal->SendingProcess();
-	frameData.info.si_uid = signal->SendingUser();
-	frameData.info.si_addr = (addr_t)signal->Address();
-	frameData.info.si_status = signal->Status();
-	frameData.info.si_band = signal->PollBand();
-	frameData.info.si_value.sival_ptr = (addr_t)signal->UserValue().sival_ptr;
-
-	// context
-	frameData.context.uc_link = (addr_t)thread->user_signal_context;
-	frameData.context.uc_sigmask = signalMask;
-	// uc_stack and uc_mcontext are filled in by the architecture specific code.
-
-	// user data
-	frameData.user_data = (addr_t)action->sa_userdata;
-
-	// handler function
-	frameData.siginfo_handler = (action->sa_flags & SA_SIGINFO) != 0;
-	frameData.handler = frameData.siginfo_handler
-		? (addr_t)action->sa_sigaction : (addr_t)action->sa_handler;
-
-	// thread flags -- save the and clear the thread's syscall restart related
-	// flags
-	frameData.thread_flags = atomic_and(&thread->flags,
-		~(THREAD_FLAGS_RESTART_SYSCALL | THREAD_FLAGS_64_BIT_SYSCALL_RETURN));
-
-	// syscall restart related fields
-	memcpy(frameData.syscall_restart_parameters,
-		thread->syscall_restart.parameters,
-		sizeof(frameData.syscall_restart_parameters));
-
-	// commpage address
-	frameData.commpage_address = (addr_t)thread->team->commpage_address;
-
-	// syscall_restart_return_value is filled in by the architecture specific
-	// code.
-
-	return arch_setup_compat_signal_frame(thread, action, &frameData);
-}
-
-#endif // _COMPAT_MODE
-
-
 /*! Actually handles pending signals -- i.e. the thread will exit, a custom
 	signal handler is prepared, or whatever the signal demands.
 	The function will not return, when a deadly signal is encountered. The
@@ -1318,11 +1258,6 @@ handle_signals(Thread* thread)
 
 		locker.Unlock();
 
-#ifdef _COMPAT_MODE
-		if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0)
-			setup_compat_signal_frame(thread, &handler, signal, oldBlockMask);
-		else
-#endif
 		setup_signal_frame(thread, &handler, signal, oldBlockMask);
 
 		// Reset sigsuspend_original_unblocked_mask. It would have been set by
@@ -2300,10 +2235,11 @@ _user_send_signal(int32 id, uint32 signalNumber,
 	// Copy the user value from userland. If not given, use a dummy value.
 	union sigval userValue;
 	if (userUserValue != NULL) {
-		status_t status = copy_ref_var_from_user((union sigval*)userUserValue,
-			userValue);
-		if (status != B_OK)
-			return status;
+		if (!IS_USER_ADDRESS(userUserValue)
+			|| user_memcpy(&userValue, userUserValue, sizeof(userValue))
+				!= B_OK) {
+			return B_BAD_ADDRESS;
+		}
 	} else
 		userValue.sival_ptr = NULL;
 
@@ -2360,23 +2296,20 @@ _user_sigaction(int signal, const struct sigaction *userAction,
 	struct sigaction act, oact;
 	status_t status;
 
-	if (userAction != NULL) {
-		status = copy_ref_var_from_user((struct sigaction*)userAction, act);
-		if (status < B_OK)
-			return status;
-	}
-	if (userOldAction != NULL) {
-		status = copy_ref_var_from_user(userOldAction, oact);
-		if (status < B_OK)
-			return status;
-	}
+	if ((userAction != NULL && (!IS_USER_ADDRESS(userAction)
+			|| user_memcpy(&act, userAction, sizeof(struct sigaction)) < B_OK))
+		|| (userOldAction != NULL && (!IS_USER_ADDRESS(userOldAction)
+			|| user_memcpy(&oact, userOldAction, sizeof(struct sigaction))
+				< B_OK)))
+		return B_BAD_ADDRESS;
 
 	status = sigaction_internal(signal, userAction ? &act : NULL,
 		userOldAction ? &oact : NULL);
 
 	// only copy the old action if a pointer has been given
-	if (status >= B_OK && userOldAction != NULL)
-		status = copy_ref_var_to_user(oact, userOldAction);
+	if (status >= B_OK && userOldAction != NULL
+		&& user_memcpy(userOldAction, &oact, sizeof(struct sigaction)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return status;
 }
@@ -2406,7 +2339,7 @@ _user_sigwait(const sigset_t *userSet, siginfo_t *userInfo, uint32 flags,
 	if (status == B_OK) {
 		// copy the info back to userland, if userSet is non-NULL
 		if (userInfo != NULL)
-			status = copy_ref_var_to_user(info, userInfo);
+			status = user_memcpy(userInfo, &info, sizeof(info));
 	} else if (status == B_INTERRUPTED) {
 		// make sure we'll be restarted
 		Thread* thread = thread_get_current_thread();
@@ -2460,17 +2393,11 @@ _user_set_signal_stack(const stack_t* newUserStack, stack_t* oldUserStack)
 	struct stack_t newStack, oldStack;
 	bool onStack = false;
 
-	if (newUserStack != NULL) {
-		status_t status = copy_ref_var_from_user((stack_t*)newUserStack,
-			newStack);
-		if (status < B_OK)
-			return status;
-	}
-	if (oldUserStack != NULL) {
-		status_t status = copy_ref_var_from_user(oldUserStack, oldStack);
-		if (status < B_OK)
-			return status;
-	}
+	if ((newUserStack != NULL && (!IS_USER_ADDRESS(newUserStack)
+			|| user_memcpy(&newStack, newUserStack, sizeof(stack_t)) < B_OK))
+		|| (oldUserStack != NULL && (!IS_USER_ADDRESS(oldUserStack)
+			|| user_memcpy(&oldStack, oldUserStack, sizeof(stack_t)) < B_OK)))
+		return B_BAD_ADDRESS;
 
 	if (thread->signal_stack_enabled) {
 		// determine whether or not the user thread is currently
@@ -2507,8 +2434,9 @@ _user_set_signal_stack(const stack_t* newUserStack, stack_t* oldUserStack)
 	}
 
 	// only copy the old stack info if a pointer has been given
-	if (oldUserStack != NULL)
-		return copy_ref_var_to_user(oldStack, oldUserStack);
+	if (oldUserStack != NULL
+		&& user_memcpy(oldUserStack, &oldStack, sizeof(stack_t)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return B_OK;
 }
@@ -2542,54 +2470,6 @@ _user_restore_signal_frame(struct signal_frame_data* userSignalFrameData)
 
 	Thread *thread = thread_get_current_thread();
 
-#ifdef _COMPAT_MODE
-	if ((thread->flags & THREAD_FLAGS_COMPAT_MODE) != 0) {
-		// copy the signal frame data from userland
-		compat_signal_frame_data signalFrameData;
-		if (userSignalFrameData == NULL || !IS_USER_ADDRESS(userSignalFrameData)
-			|| user_memcpy(&signalFrameData, userSignalFrameData,
-				sizeof(signalFrameData)) != B_OK) {
-			// We failed to copy the signal frame data from userland. This is a
-			// serious problem. Kill the thread.
-			dprintf("_user_restore_signal_frame(): thread %" B_PRId32 ": Failed to "
-				"copy signal frame data (%p) from userland. Killing thread...\n",
-				thread->id, userSignalFrameData);
-			kill_thread(thread->id);
-			return B_BAD_ADDRESS;
-		}
-
-		// restore the signal block mask
-		InterruptsSpinLocker locker(thread->team->signal_lock);
-
-		thread->sig_block_mask
-			= signalFrameData.context.uc_sigmask & BLOCKABLE_SIGNALS;
-		update_current_thread_signals_flag();
-
-		locker.Unlock();
-
-		// restore the syscall restart related thread flags and the syscall restart
-		// parameters
-		atomic_and(&thread->flags,
-			~(THREAD_FLAGS_RESTART_SYSCALL | THREAD_FLAGS_64_BIT_SYSCALL_RETURN));
-		atomic_or(&thread->flags, signalFrameData.thread_flags
-			& (THREAD_FLAGS_RESTART_SYSCALL | THREAD_FLAGS_64_BIT_SYSCALL_RETURN));
-
-		memcpy(thread->syscall_restart.parameters,
-			signalFrameData.syscall_restart_parameters,
-			sizeof(thread->syscall_restart.parameters));
-
-		// restore the previously stored Thread::user_signal_context
-		thread->user_signal_context = (ucontext_t*)(addr_t)signalFrameData.context.uc_link;
-		if (thread->user_signal_context != NULL
-			&& !IS_USER_ADDRESS(thread->user_signal_context)) {
-			thread->user_signal_context = NULL;
-		}
-
-		// let the architecture specific code restore the registers
-		return arch_restore_compat_signal_frame(&signalFrameData);
-	}
-#endif
-
 	// copy the signal frame data from userland
 	signal_frame_data signalFrameData;
 	if (userSignalFrameData == NULL || !IS_USER_ADDRESS(userSignalFrameData)
diff --git a/src/system/kernel/system_info.cpp b/src/system/kernel/system_info.cpp
index e6ed65acdf..82431a94ea 100644
--- a/src/system/kernel/system_info.cpp
+++ b/src/system/kernel/system_info.cpp
@@ -31,9 +31,6 @@
 #include <lock.h>
 #include <Notifications.h>
 #include <messaging.h>
-#ifdef _COMPAT_MODE
-#	include <OS_compat.h>
-#endif
 #include <port.h>
 #include <real_time_clock.h>
 #include <sem.h>
@@ -41,7 +38,6 @@
 #include <team.h>
 #include <thread.h>
 #include <util/AutoLock.h>
-#include <util/syscall_args.h>
 #include <vm/vm.h>
 #include <vm/vm_page.h>
 
@@ -549,8 +545,13 @@ _user_get_system_info(system_info* userInfo)
 
 	system_info info;
 	status_t status = get_system_info(&info);
-	if (status == B_OK)
-		return copy_ref_var_to_user(info, userInfo);
+	if (status == B_OK) {
+		if (user_memcpy(userInfo, &info, sizeof(system_info)) < B_OK)
+			return B_BAD_ADDRESS;
+
+		return B_OK;
+	}
+
 	return status;
 }
 
diff --git a/src/system/kernel/vm/vm.cpp b/src/system/kernel/vm/vm.cpp
index a5b961b1e9..478a0e5ba7 100644
--- a/src/system/kernel/vm/vm.cpp
+++ b/src/system/kernel/vm/vm.cpp
@@ -47,17 +47,12 @@
 #include <team.h>
 #include <tracing.h>
 #include <util/AutoLock.h>
-#include <util/syscall_args.h>
 #include <vm/vm_page.h>
 #include <vm/vm_priv.h>
 #include <vm/VMAddressSpace.h>
 #include <vm/VMArea.h>
 #include <vm/VMCache.h>
 
-#ifdef _COMPAT_MODE
-#	include <OS_compat.h>
-#endif
-
 #include "VMAddressSpaceLocking.h"
 #include "VMAnonymousCache.h"
 #include "VMAnonymousNoSwapCache.h"
@@ -6008,44 +6003,6 @@ _get_next_area_info(team_id team, ssize_t* cookie, area_info* info, size_t size)
 }
 
 
-#ifdef _COMPAT_MODE
-status_t
-_compat_get_next_area_info(team_id team, ssize_t* cookie, area_info* info, size_t size)
-{
-	area_id nextID = *(area_id*)cookie;
-
-	// we're already through the list
-	if (nextID == (area_id)-1)
-		return B_ENTRY_NOT_FOUND;
-
-	if (team == B_CURRENT_TEAM)
-		team = team_get_current_team_id();
-
-	AddressSpaceReadLocker locker(team);
-	if (!locker.IsLocked())
-		return B_BAD_TEAM_ID;
-
-	VMArea* area;
-	for (VMAddressSpace::AreaIterator it
-				= locker.AddressSpace()->GetAreaIterator();
-			(area = it.Next()) != NULL;) {
-		if (area->id > nextID)
-			break;
-	}
-
-	if (area == NULL) {
-		nextID = (area_id)-1;
-		return B_ENTRY_NOT_FOUND;
-	}
-
-	fill_area_info(area, info, size);
-	*cookie = (ssize_t)(area->id);
-
-	return B_OK;
-}
-#endif
-
-
 status_t
 set_area_protection(area_id area, uint32 newProtection)
 {
@@ -6175,22 +6132,23 @@ _user_reserve_address_range(addr_t* userAddress, uint32 addressSpec,
 
 	addr_t address;
 
-	status_t status = copy_ref_var_from_user(userAddress, address);
-	if (status != B_OK)
-		return status;
+	if (!IS_USER_ADDRESS(userAddress)
+		|| user_memcpy(&address, userAddress, sizeof(address)) != B_OK)
+		return B_BAD_ADDRESS;
 
-	status = vm_reserve_address_range(
+	status_t status = vm_reserve_address_range(
 		VMAddressSpace::CurrentID(), (void**)&address, addressSpec, size,
 		RESERVED_AVOID_BASE);
 	if (status != B_OK)
 		return status;
 
-	status = copy_ref_var_to_user(address, userAddress);
-	if (status != B_OK) {
+	if (user_memcpy(userAddress, &address, sizeof(address)) != B_OK) {
 		vm_unreserve_address_range(VMAddressSpace::CurrentID(),
 			(void*)address, size);
+		return B_BAD_ADDRESS;
 	}
-	return status;
+
+	return B_OK;
 }
 
 
@@ -6236,8 +6194,10 @@ _user_get_area_info(area_id area, area_info* userInfo)
 	// TODO: do we want to prevent userland from seeing kernel protections?
 	//info.protection &= B_USER_PROTECTION;
 
-	return copy_ref_var_to_user(info, userInfo);
+	if (user_memcpy(userInfo, &info, sizeof(area_info)) < B_OK)
+		return B_BAD_ADDRESS;
 
+	return status;
 }
 
 
@@ -6247,28 +6207,21 @@ _user_get_next_area_info(team_id team, ssize_t* userCookie, area_info* userInfo)
 	ssize_t cookie;
 
 	if (!IS_USER_ADDRESS(userCookie)
-		|| !IS_USER_ADDRESS(userInfo))
+		|| !IS_USER_ADDRESS(userInfo)
+		|| user_memcpy(&cookie, userCookie, sizeof(ssize_t)) < B_OK)
 		return B_BAD_ADDRESS;
 
-	status_t status = copy_ref_var_from_user(userCookie, cookie);
-	if (status != B_OK)
-		return status;
-
 	area_info info;
-#ifdef _COMPAT_MODE
-	status = _compat_get_next_area_info(team, &cookie, &info,
-#else
-	status = _get_next_area_info(team, &cookie, &info,
-#endif
+	status_t status = _get_next_area_info(team, &cookie, &info,
 		sizeof(area_info));
 	if (status != B_OK)
 		return status;
 
 	//info.protection &= B_USER_PROTECTION;
 
-	status = copy_ref_var_to_user(cookie, userCookie);
-	if (status == B_OK)
-		status = copy_ref_var_to_user(info, userInfo);
+	if (user_memcpy(userCookie, &cookie, sizeof(ssize_t)) < B_OK
+		|| user_memcpy(userInfo, &info, sizeof(area_info)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return status;
 }
@@ -6306,17 +6259,16 @@ _user_transfer_area(area_id area, void** userAddress, uint32 addressSpec,
 	}
 
 	void* address;
-	status_t status = copy_ref_var_from_user(userAddress, address);
-	if (status != B_OK)
-		return status;
+	if (!IS_USER_ADDRESS(userAddress)
+		|| user_memcpy(&address, userAddress, sizeof(address)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	area_id newArea = transfer_area(area, &address, addressSpec, target, false);
 	if (newArea < B_OK)
 		return newArea;
 
-	status = copy_ref_var_to_user(address, userAddress);
-	if (status != B_OK)
-		return status;
+	if (user_memcpy(userAddress, &address, sizeof(address)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return newArea;
 }
@@ -6339,13 +6291,11 @@ _user_clone_area(const char* userName, void** userAddress, uint32 addressSpec,
 		return B_BAD_VALUE;
 
 	if (!IS_USER_ADDRESS(userName)
-		|| user_strlcpy(name, userName, sizeof(name)) < B_OK)
+		|| !IS_USER_ADDRESS(userAddress)
+		|| user_strlcpy(name, userName, sizeof(name)) < B_OK
+		|| user_memcpy(&address, userAddress, sizeof(address)) < B_OK)
 		return B_BAD_ADDRESS;
 
-	status_t status = copy_ref_var_from_user(userAddress, address);
-	if (status != B_OK)
-		return status;
-
 	fix_protection(&protection);
 
 	area_id clonedArea = vm_clone_area(VMAddressSpace::CurrentID(), name,
@@ -6354,10 +6304,9 @@ _user_clone_area(const char* userName, void** userAddress, uint32 addressSpec,
 	if (clonedArea < B_OK)
 		return clonedArea;
 
-	status = copy_ref_var_to_user(address, userAddress);
-	if (status < B_OK) {
+	if (user_memcpy(userAddress, &address, sizeof(address)) < B_OK) {
 		delete_area(clonedArea);
-		return status;
+		return B_BAD_ADDRESS;
 	}
 
 	return clonedArea;
@@ -6381,13 +6330,11 @@ _user_create_area(const char* userName, void** userAddress, uint32 addressSpec,
 		return B_BAD_VALUE;
 
 	if (!IS_USER_ADDRESS(userName)
-		|| user_strlcpy(name, userName, sizeof(name)) < B_OK)
+		|| !IS_USER_ADDRESS(userAddress)
+		|| user_strlcpy(name, userName, sizeof(name)) < B_OK
+		|| user_memcpy(&address, userAddress, sizeof(address)) < B_OK)
 		return B_BAD_ADDRESS;
 
-	status_t status = copy_ref_var_from_user(userAddress, address);
-	if (status != B_OK)
-		return status;
-
 	if (addressSpec == B_EXACT_ADDRESS
 		&& IS_KERNEL_ADDRESS(address))
 		return B_BAD_VALUE;
@@ -6407,12 +6354,10 @@ _user_create_area(const char* userName, void** userAddress, uint32 addressSpec,
 		size, lock, protection, 0, 0, &virtualRestrictions,
 		&physicalRestrictions, false, &address);
 
-	if (area >= B_OK) {
-		status = copy_ref_var_to_user(address, userAddress);
-		if (status < B_OK) {
-			delete_area(area);
-			return status;
-		}
+	if (area >= B_OK
+		&& user_memcpy(userAddress, &address, sizeof(address)) < B_OK) {
+		delete_area(area);
+		return B_BAD_ADDRESS;
 	}
 
 	return area;
@@ -6446,14 +6391,11 @@ _user_map_file(const char* userName, void** userAddress, uint32 addressSpec,
 
 	fix_protection(&protection);
 
-	if (!IS_USER_ADDRESS(userName)
-		|| user_strlcpy(name, userName, B_OS_NAME_LENGTH) < B_OK)
+	if (!IS_USER_ADDRESS(userName) || !IS_USER_ADDRESS(userAddress)
+		|| user_strlcpy(name, userName, B_OS_NAME_LENGTH) < B_OK
+		|| user_memcpy(&address, userAddress, sizeof(address)) < B_OK)
 		return B_BAD_ADDRESS;
 
-	status_t status = copy_ref_var_from_user(userAddress, address);
-	if (status != B_OK)
-		return status;
-
 	if (addressSpec == B_EXACT_ADDRESS) {
 		if ((addr_t)address + size < (addr_t)address
 				|| (addr_t)address % B_PAGE_SIZE != 0) {
@@ -6471,11 +6413,8 @@ _user_map_file(const char* userName, void** userAddress, uint32 addressSpec,
 	if (area < B_OK)
 		return area;
 
-	status = copy_ref_var_to_user(address, userAddress);
-	if (status < B_OK) {
-		delete_area(area);
-		return status;
-	}
+	if (user_memcpy(userAddress, &address, sizeof(address)) < B_OK)
+		return B_BAD_ADDRESS;
 
 	return area;
 }