diff --git a/headers/private/kernel/arch/ppc/arch_config.h b/headers/private/kernel/arch/ppc/arch_config.h
index 4e0c4aca5d..1c57d08987 100644
--- a/headers/private/kernel/arch/ppc/arch_config.h
+++ b/headers/private/kernel/arch/ppc/arch_config.h
@@ -1,13 +1,15 @@
 /*
-** Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
-** Distributed under the terms of the Haiku License.
-*/
+ * Copyright 2004, Axel Dörfler, axeld@pinc-software.de.
+ * Distributed under the terms of the MIT License.
+ */
 #ifndef _KERNEL_ARCH_PPC_CONFIG_H
 #define _KERNEL_ARCH_PPC_CONFIG_H
 
 
 #define FUNCTION_CALL_PARAMETER_ALIGNMENT_TYPE	unsigned int
 
+#define STACK_GROWS_DOWNWARDS
+
 //#define ATOMIC_FUNCS_ARE_SYSCALLS
 #define ATOMIC64_FUNCS_ARE_SYSCALLS
 
diff --git a/headers/private/kernel/arch/x86/arch_config.h b/headers/private/kernel/arch/x86/arch_config.h
index 9718fb117b..5380954ad8 100644
--- a/headers/private/kernel/arch/x86/arch_config.h
+++ b/headers/private/kernel/arch/x86/arch_config.h
@@ -1,12 +1,14 @@
 /*
-** Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
-** Distributed under the terms of the Haiku License.
-*/
+ * Copyright 2004, Axel Dörfler, axeld@pinc-software.de.
+ * Distributed under the terms of the MIT License.
+ */
 #ifndef _KERNEL_ARCH_x86_CONFIG_H
 #define _KERNEL_ARCH_x86_CONFIG_H
 
 #define FUNCTION_CALL_PARAMETER_ALIGNMENT_TYPE  unsigned int
 
+#define STACK_GROWS_DOWNWARDS
+
 //#define ATOMIC_FUNCS_ARE_SYSCALLS
 //#define ATOMIC64_FUNCS_ARE_SYSCALLS