diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 50f8c5e..bed9665 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -228,11 +228,6 @@
 void *copy_from_fs(void *dst, addr_t src, size_t len);
 void copy_to_gs(addr_t dst, void *src, size_t len);
 void *copy_from_gs(void *dst, addr_t src, size_t len);
-void *memcpy(void *dst, void *src, size_t len);
-void *memset(void *dst, int c, size_t len);
-
-#define memcpy(d,s,l) __builtin_memcpy(d,s,l)
-#define memset(d,c,l) __builtin_memset(d,c,l)
 
 /* a20.c */
 int enable_a20(void);
diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
index 100a9a1..086c4f4 100644
--- a/arch/x86/boot/cpucheck.c
+++ b/arch/x86/boot/cpucheck.c
@@ -27,6 +27,7 @@
 #include <asm/processor-flags.h>
 #include <asm/required-features.h>
 #include <asm/msr-index.h>
+#include "string.h"
 
 static u32 err_flags[NCAPINTS];
 
diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c
index c501a5b..223e425 100644
--- a/arch/x86/boot/edd.c
+++ b/arch/x86/boot/edd.c
@@ -15,6 +15,7 @@
 
 #include "boot.h"
 #include <linux/edd.h>
+#include "string.h"
 
 #if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
 
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index cf6083d..fd6c9f2 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -14,6 +14,7 @@
  */
 
 #include "boot.h"
+#include "string.h"
 
 struct boot_params boot_params __attribute__((aligned(16)));
 
diff --git a/arch/x86/boot/regs.c b/arch/x86/boot/regs.c
index 958019b..c0fb356 100644
--- a/arch/x86/boot/regs.c
+++ b/arch/x86/boot/regs.c
@@ -17,6 +17,7 @@
  */
 
 #include "boot.h"
+#include "string.h"
 
 void initregs(struct biosregs *reg)
 {
diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h
new file mode 100644
index 0000000..10939d8
--- /dev/null
+++ b/arch/x86/boot/string.h
@@ -0,0 +1,19 @@
+#ifndef BOOT_STRING_H
+#define BOOT_STRING_H
+
+/* Undef any of these macros coming from string_32.h. */
+#undef memcpy
+#undef memset
+#undef memcmp
+
+void *memcpy(void *dst, const void *src, size_t len);
+void *memset(void *dst, int c, size_t len);
+
+/*
+ * Access builtin version by default. If one needs to use optimized version,
+ * do "undef memcpy" in .c file and link against right string.c
+ */
+#define memcpy(d,s,l) __builtin_memcpy(d,s,l)
+#define memset(d,c,l) __builtin_memset(d,c,l)
+
+#endif /* BOOT_STRING_H */
diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c
index 11e8c6e..ba3e100 100644
--- a/arch/x86/boot/video-vesa.c
+++ b/arch/x86/boot/video-vesa.c
@@ -16,6 +16,7 @@
 #include "boot.h"
 #include "video.h"
 #include "vesa.h"
+#include "string.h"
 
 /* VESA information */
 static struct vesa_general_info vginfo;