Index: kernel/arch/amd64/src/userspace.c
===================================================================
--- kernel/arch/amd64/src/userspace.c	(revision 88e43bc385a97c7449a8a8bdd10a598a9497c134)
+++ kernel/arch/amd64/src/userspace.c	(revision 1743f8e4f6cec91f83c5d1bb547144cbbc03364d)
@@ -66,5 +66,5 @@
 	    "iretq\n"
 	    :: [udata_des] "i" (GDT_SELECTOR(UDATA_DES) | PL_USER),
-	      [stack_top] "r" ((uint8_t *) kernel_uarg->uspace_stack +
+	      [stack_top] "r" (kernel_uarg->uspace_stack +
 	      kernel_uarg->uspace_stack_size),
 	      [rflags] "r" (rflags),