diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index b7bf3505e1ec..347555492dad 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -6,6 +6,8 @@
 
 #define COMMAND_LINE_SIZE 2048
 
+#include <linux/linkage.h>
+
 #ifdef __i386__
 
 #include <linux/pfn.h>
@@ -108,11 +110,11 @@ void *extend_brk(size_t size, size_t align);
 extern void probe_roms(void);
 #ifdef __i386__
 
-void __init i386_start_kernel(void);
+asmlinkage void __init i386_start_kernel(void);
 
 #else
-void __init x86_64_start_kernel(char *real_mode);
-void __init x86_64_start_reservations(char *real_mode_data);
+asmlinkage void __init x86_64_start_kernel(char *real_mode);
+asmlinkage void __init x86_64_start_reservations(char *real_mode_data);
 
 #endif /* __i386__ */
 #endif /* _SETUP */
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 138463a24877..06f87bece92a 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -29,7 +29,7 @@ static void __init i386_default_early_setup(void)
 	reserve_ebda_region();
 }
 
-void __init i386_start_kernel(void)
+asmlinkage void __init i386_start_kernel(void)
 {
 	sanitize_boot_params(&boot_params);
 
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 55b67614ed94..1be8e43b669e 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -137,7 +137,7 @@ static void __init copy_bootdata(char *real_mode_data)
 	}
 }
 
-void __init x86_64_start_kernel(char * real_mode_data)
+asmlinkage void __init x86_64_start_kernel(char * real_mode_data)
 {
 	int i;