diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 453b0c72..e15d6adb 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -1707,7 +1707,7 @@ SYSCALL_DECLARE(mmap)
 		| MAP_NONBLOCK		// 0x10000
 		;
 
-	const intptr_t addr0 = ihk_mc_syscall_arg0(ctx);
+	const uintptr_t addr0 = ihk_mc_syscall_arg0(ctx);
 	const size_t len0 = ihk_mc_syscall_arg1(ctx);
 	const int prot = ihk_mc_syscall_arg2(ctx);
 	const int flags0 = ihk_mc_syscall_arg3(ctx);
@@ -1716,7 +1716,7 @@ SYSCALL_DECLARE(mmap)
 	struct thread *thread = cpu_local_var(current);
 	struct vm_regions *region = &thread->vm->region;
 	int error;
-	intptr_t addr = 0;
+	uintptr_t addr = 0;
 	size_t len;
 	int flags = flags0;
 	size_t pgsize;
diff --git a/arch/x86_64/kernel/syscall.c b/arch/x86_64/kernel/syscall.c
index dd5f7721..230fa98c 100644
--- a/arch/x86_64/kernel/syscall.c
+++ b/arch/x86_64/kernel/syscall.c
@@ -1560,7 +1560,7 @@ SYSCALL_DECLARE(mmap)
 		| MAP_NONBLOCK		// 00010000
 		;
 
-	const intptr_t addr0 = ihk_mc_syscall_arg0(ctx);
+	const uintptr_t addr0 = ihk_mc_syscall_arg0(ctx);
 	const size_t len0 = ihk_mc_syscall_arg1(ctx);
 	const int prot = ihk_mc_syscall_arg2(ctx);
 	const int flags0 = ihk_mc_syscall_arg3(ctx);
@@ -1569,7 +1569,7 @@ SYSCALL_DECLARE(mmap)
 	struct thread *thread = cpu_local_var(current);
 	struct vm_regions *region = &thread->vm->region;
 	int error;
-	intptr_t addr = 0;
+	uintptr_t addr = 0;
 	size_t len;
 	int flags = flags0;
 	size_t pgsize;
diff --git a/kernel/include/syscall.h b/kernel/include/syscall.h
index 158599e2..7ddef9b1 100644
--- a/kernel/include/syscall.h
+++ b/kernel/include/syscall.h
@@ -465,7 +465,7 @@ static inline unsigned long timespec_to_jiffy(const struct timespec *ats)
 void reset_cputime(void);
 void set_cputime(int mode);
 int do_munmap(void *addr, size_t len, int holding_memory_range_lock);
-intptr_t do_mmap(intptr_t addr0, size_t len0, int prot, int flags, int fd,
+intptr_t do_mmap(uintptr_t addr0, size_t len0, int prot, int flags, int fd,
 		off_t off0);
 void clear_host_pte(uintptr_t addr, size_t len);
 typedef int32_t key_t;
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 3608d279..aeb2b72f 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -1558,7 +1558,7 @@ int do_munmap(void *addr, size_t len, int holding_memory_range_lock)
 	return error;
 }
 
-static int search_free_space(size_t len, int pgshift, intptr_t *addrp)
+static int search_free_space(size_t len, int pgshift, uintptr_t *addrp)
 {
 	struct thread *thread = cpu_local_var(current);
 	struct vm_regions *region = &thread->vm->region;
@@ -1600,12 +1600,12 @@ out:
 }
 
 intptr_t
-do_mmap(const intptr_t addr0, const size_t len0, const int prot,
+do_mmap(const uintptr_t addr0, const size_t len0, const int prot,
 	const int flags, const int fd, const off_t off0)
 {
 	struct thread *thread = cpu_local_var(current);
 	struct vm_regions *region = &thread->vm->region;
-	intptr_t addr = addr0;
+	uintptr_t addr = addr0;
 	size_t len = len0;
 	size_t populate_len = 0;
 	off_t off;
@@ -5229,7 +5229,7 @@ SYSCALL_DECLARE(shmat)
 	struct process_vm *vm = thread->vm;
 	size_t len;
 	int error;
-	intptr_t addr;
+	uintptr_t addr;
 	int prot;
 	int vrflags;
 	int req;
@@ -8105,8 +8105,7 @@ SYSCALL_DECLARE(mremap)
 			goto out;
 		}
 		need_relocate = 1;
-		error = search_free_space(newsize, range->pgshift,
-				(intptr_t *)&newstart);
+		error = search_free_space(newsize, range->pgshift, &newstart);
 		if (error) {
 			ekprintf("sys_mremap(%#lx,%#lx,%#lx,%#x,%#lx):"
 					"search failed. %d\n",