diff --git a/arch/x86/kernel/memory.c b/arch/x86/kernel/memory.c
index 9aed39d8..1448f224 100644
--- a/arch/x86/kernel/memory.c
+++ b/arch/x86/kernel/memory.c
@@ -2159,30 +2159,8 @@ void *phys_to_virt(unsigned long p)
 int copy_from_user(void *dst, const void *src, size_t siz)
 {
 	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	size_t pos;
-	size_t wsiz;
-	unsigned long pgstart = (unsigned long)src;
 
-	wsiz = siz + (pgstart & 0x0000000000000fffUL);
-	pgstart &= 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	for(pos = 0; pos < wsiz; pos += 4096, pgstart += 4096){
-		range = lookup_process_memory_range(vm, pgstart, pgstart+1);
-		if(range == NULL){
-			ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-			return -EFAULT;
-		}
-		if((range->flag & VR_PROT_MASK) == VR_PROT_NONE){
-			ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-			return -EFAULT;
-		}
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	memcpy(dst, src, siz);
-	return 0;
+	return read_process_vm(vm, dst, src, siz);
 }
 
 int strlen_user(const char *s)
@@ -2261,50 +2239,28 @@ int strcpy_from_user(char *dst, const char *src)
 
 long getlong_user(const long *p)
 {
-	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	unsigned long plong = (unsigned long)p;
-	unsigned long pgstart;
+	int error;
+	long l;
 
-	pgstart = plong & 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	range = lookup_process_memory_range(vm, plong, plong + sizeof(long));
-	if(range == NULL){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
+	error = copy_from_user(&l, p, sizeof(l));
+	if (error) {
+		return error;
 	}
-	if((range->flag & VR_PROT_MASK) == VR_PROT_NONE){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	return *p;
+
+	return l;
 }
 
 int getint_user(const int *p)
 {
-	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	unsigned long pint = (unsigned long)p;
-	unsigned long pgstart;
+	int error;
+	int i;
 
-	pgstart = pint & 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	range = lookup_process_memory_range(vm, pint, pint + sizeof(int));
-	if(range == NULL){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
+	error = copy_from_user(&i, p, sizeof(i));
+	if (error) {
+		return error;
 	}
-	if((range->flag & VR_PROT_MASK) == VR_PROT_NONE){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	return *p;
+
+	return i;
 }
 
 int read_process_vm(struct process_vm *vm, void *kdst, const void *usrc, size_t siz)
@@ -2363,83 +2319,18 @@ int read_process_vm(struct process_vm *vm, void *kdst, const void *usrc, size_t
 int copy_to_user(void *dst, const void *src, size_t siz)
 {
 	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	size_t pos;
-	size_t wsiz;
-	unsigned long pgstart = (unsigned long)dst;
 
-	wsiz = siz + (pgstart & 0x0000000000000fffUL);
-	pgstart &= 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	for(pos = 0; pos < wsiz; pos += 4096, pgstart += 4096){
-		range = lookup_process_memory_range(vm, pgstart, pgstart+1);
-		if(range == NULL){
-			ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-			return -EFAULT;
-		}
-		if(((range->flag & VR_PROT_MASK) == VR_PROT_NONE) ||
-		    !(range->flag & VR_PROT_WRITE)){
-			ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-			return -EFAULT;
-		}
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	memcpy(dst, src, siz);
-	return 0;
+	return write_process_vm(vm, dst, src, siz);
 }
 
 int setlong_user(long *dst, long data)
 {
-	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	unsigned long plong = (unsigned long)dst;
-	unsigned long pgstart;
-
-	pgstart = plong & 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	range = lookup_process_memory_range(vm, plong, plong + sizeof(long));
-	if(range == NULL){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	if(((range->flag & VR_PROT_MASK) == VR_PROT_NONE) ||
-	    !(range->flag & VR_PROT_WRITE)){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	*dst = data;
-	return 0;
+	return copy_to_user(dst, &data, sizeof(data));
 }
 
 int setint_user(int *dst, int data)
 {
-	struct process_vm *vm = cpu_local_var(current)->vm;
-	struct vm_range *range;
-	unsigned long pint = (unsigned long)dst;
-	unsigned long pgstart;
-
-	pgstart = pint & 0xfffffffffffff000UL;
-	if(!pgstart || pgstart >= MAP_KERNEL_START)
-		return -EFAULT;
-	ihk_mc_spinlock_lock_noirq(&vm->memory_range_lock);
-	range = lookup_process_memory_range(vm, pint, pint + sizeof(int));
-	if(range == NULL){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	if(((range->flag & VR_PROT_MASK) == VR_PROT_NONE) ||
-	    !(range->flag & VR_PROT_WRITE)){
-		ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-		return -EFAULT;
-	}
-	ihk_mc_spinlock_unlock_noirq(&vm->memory_range_lock);
-	*dst = data;
-	return 0;
+	return copy_to_user(dst, &data, sizeof(data));
 }
 
 int write_process_vm(struct process_vm *vm, void *udst, const void *ksrc, size_t siz)