diff --git a/arch/um/include/as-layout.h b/arch/um/include/as-layout.h
index a5cdf953e04a..2b859e020ac6 100644
--- a/arch/um/include/as-layout.h
+++ b/arch/um/include/as-layout.h
@@ -10,24 +10,32 @@
 #include "kern_constants.h"
 
 /*
- * Assembly doesn't want any casting, but C does, so define these
- * without casts here, and define new symbols with casts inside the C
- * section.
+ * Stolen from linux/const.h, which can't be directly included since
+ * this is used in userspace code, which has no access to the kernel
+ * headers.  Changed to be suitable for adding casts to the start,
+ * rather than "UL" to the end.
  */
-#define ASM_STUB_CODE (UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
-#define ASM_STUB_DATA (UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
-#define ASM_STUB_START ASM_STUB_CODE
 
-/*
- * This file is included by the assembly stubs, which just want the
- * definitions above.
+/* Some constant macros are used in both assembler and
+ * C code.  Therefore we cannot annotate them always with
+ * 'UL' and other type specifiers unilaterally.  We
+ * use the following macros to deal with this.
  */
+
+#ifdef __ASSEMBLY__
+#define _AC(X, Y)	(Y)
+#else
+#define __AC(X, Y)	(X (Y))
+#define _AC(X, Y)	__AC(X, Y)
+#endif
+
+#define STUB_CODE _AC((unsigned long), \
+		      UML_CONFIG_TOP_ADDR - 2 * UM_KERN_PAGE_SIZE)
+#define STUB_DATA _AC((unsigned long), UML_CONFIG_TOP_ADDR - UM_KERN_PAGE_SIZE)
+#define STUB_START _AC(, STUB_CODE)
+
 #ifndef __ASSEMBLY__
 
-#define STUB_CODE ((unsigned long) ASM_STUB_CODE)
-#define STUB_DATA ((unsigned long) ASM_STUB_DATA)
-#define STUB_START ((unsigned long) ASM_STUB_START)
-
 #include "sysdep/ptrace.h"
 
 struct cpu_task {
diff --git a/arch/um/sys-i386/stub.S b/arch/um/sys-i386/stub.S
index e730772c401b..7699e89f660f 100644
--- a/arch/um/sys-i386/stub.S
+++ b/arch/um/sys-i386/stub.S
@@ -7,7 +7,7 @@
 	.globl batch_syscall_stub
 batch_syscall_stub:
 	/* load pointer to first operation */
-	mov	$(ASM_STUB_DATA+8), %esp
+	mov	$(STUB_DATA+8), %esp
 
 again:
 	/* load length of additional data */
@@ -15,12 +15,12 @@ again:
 
 	/* if(length == 0) : end of list */
 	/* write possible 0 to header */
-	mov	%eax, ASM_STUB_DATA+4
+	mov	%eax, STUB_DATA+4
 	cmpl	$0, %eax
 	jz	done
 
 	/* save current pointer */
-	mov	%esp, ASM_STUB_DATA+4
+	mov	%esp, STUB_DATA+4
 
 	/* skip additional data */
 	add	%eax, %esp
@@ -46,7 +46,7 @@ again:
 
 done:
 	/* save return value */
-	mov	%eax, ASM_STUB_DATA
+	mov	%eax, STUB_DATA
 
 	/* stop */
 	int3
diff --git a/arch/um/sys-x86_64/stub.S b/arch/um/sys-x86_64/stub.S
index 4afe204a6af7..568768763155 100644
--- a/arch/um/sys-x86_64/stub.S
+++ b/arch/um/sys-x86_64/stub.S
@@ -8,18 +8,18 @@ syscall_stub:
 	/* We don't have 64-bit constants, so this constructs the address
 	 * we need.
 	 */
-	movq	$(ASM_STUB_DATA >> 32), %rbx
+	movq	$(STUB_DATA >> 32), %rbx
 	salq	$32, %rbx
-	movq	$(ASM_STUB_DATA & 0xffffffff), %rcx
+	movq	$(STUB_DATA & 0xffffffff), %rcx
 	or	%rcx, %rbx
 	movq	%rax, (%rbx)
 	int3
 
 	.globl batch_syscall_stub
 batch_syscall_stub:
-	mov	$(ASM_STUB_DATA >> 32), %rbx
+	mov	$(STUB_DATA >> 32), %rbx
 	sal	$32, %rbx
-	mov	$(ASM_STUB_DATA & 0xffffffff), %rax
+	mov	$(STUB_DATA & 0xffffffff), %rax
 	or	%rax, %rbx
 	/* load pointer to first operation */
 	mov	%rbx, %rsp