diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 50f8c5e0f37e..bd49ec61255c 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -177,14 +177,6 @@ static inline void wrgs32(u32 v, addr_t addr)
 }
 
 /* Note: these only return true/false, not a signed return value! */
-static inline int memcmp(const void *s1, const void *s2, size_t len)
-{
-	u8 diff;
-	asm("repe; cmpsb; setnz %0"
-	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
-	return diff;
-}
-
 static inline int memcmp_fs(const void *s1, addr_t s2, size_t len)
 {
 	u8 diff;
@@ -228,11 +220,6 @@ void copy_to_fs(addr_t dst, void *src, size_t len);
 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/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 196eaf373a06..17684615374b 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -10,6 +10,7 @@
  */
 
 #include "misc.h"
+#include "../string.h"
 
 /* WARNING!!
  * This code is compiled with -fPIC and it is relocated dynamically
@@ -97,8 +98,14 @@
  */
 #define STATIC		static
 
-#undef memset
 #undef memcpy
+
+/*
+ * Use a normal definition of memset() from string.c. There are already
+ * included header files which expect a definition of memset() and by
+ * the time we define memset macro, it is too late.
+ */
+#undef memset
 #define memzero(s, n)	memset((s), 0, (n))
 
 
@@ -109,9 +116,6 @@ static void error(char *m);
  */
 struct boot_params *real_mode;		/* Pointer to real-mode data */
 
-void *memset(void *s, int c, size_t n);
-void *memcpy(void *dest, const void *src, size_t n);
-
 memptr free_mem_ptr;
 memptr free_mem_end_ptr;
 
@@ -216,45 +220,6 @@ void __putstr(const char *s)
 	outb(0xff & (pos >> 1), vidport+1);
 }
 
-void *memset(void *s, int c, size_t n)
-{
-	int i;
-	char *ss = s;
-
-	for (i = 0; i < n; i++)
-		ss[i] = c;
-	return s;
-}
-#ifdef CONFIG_X86_32
-void *memcpy(void *dest, const void *src, size_t n)
-{
-	int d0, d1, d2;
-	asm volatile(
-		"rep ; movsl\n\t"
-		"movl %4,%%ecx\n\t"
-		"rep ; movsb\n\t"
-		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
-		: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
-		: "memory");
-
-	return dest;
-}
-#else
-void *memcpy(void *dest, const void *src, size_t n)
-{
-	long d0, d1, d2;
-	asm volatile(
-		"rep ; movsq\n\t"
-		"movq %4,%%rcx\n\t"
-		"rep ; movsb\n\t"
-		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
-		: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
-		: "memory");
-
-	return dest;
-}
-#endif
-
 static void error(char *x)
 {
 	error_putstr("\n\n");
diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index ffb9c5c9d748..f3c57e341402 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -1,11 +1,45 @@
 #include "misc.h"
-
-int memcmp(const void *s1, const void *s2, size_t len)
-{
-	u8 diff;
-	asm("repe; cmpsb; setnz %0"
-	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
-	return diff;
-}
-
 #include "../string.c"
+
+/* misc.h might pull in string_32.h which has a macro for memcpy. undef that */
+#undef memcpy
+
+#ifdef CONFIG_X86_32
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	int d0, d1, d2;
+	asm volatile(
+		"rep ; movsl\n\t"
+		"movl %4,%%ecx\n\t"
+		"rep ; movsb\n\t"
+		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
+		: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
+		: "memory");
+
+	return dest;
+}
+#else
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	long d0, d1, d2;
+	asm volatile(
+		"rep ; movsq\n\t"
+		"movq %4,%%rcx\n\t"
+		"rep ; movsb\n\t"
+		: "=&c" (d0), "=&D" (d1), "=&S" (d2)
+		: "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
+		: "memory");
+
+	return dest;
+}
+#endif
+
+void *memset(void *s, int c, size_t n)
+{
+	int i;
+	char *ss = s;
+
+	for (i = 0; i < n; i++)
+		ss[i] = c;
+	return s;
+}
diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
index f0d0b20fe149..1fd7d575092e 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 c501a5b466f8..223e42527077 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 cf6083d444f4..fd6c9f236996 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 958019b1cfa5..c0fb356a3092 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.c b/arch/x86/boot/string.c
index 574dedfe2890..5339040ef86e 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -14,6 +14,20 @@
 
 #include "boot.h"
 
+/*
+ * This file gets included in compressed/string.c which might pull in
+ * string_32.h and which in turn maps memcmp to __builtin_memcmp(). Undo
+ * that first.
+ */
+#undef memcmp
+int memcmp(const void *s1, const void *s2, size_t len)
+{
+	u8 diff;
+	asm("repe; cmpsb; setnz %0"
+	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
+	return diff;
+}
+
 int strcmp(const char *str1, const char *str2)
 {
 	const unsigned char *s1 = (const unsigned char *)str1;
diff --git a/arch/x86/boot/string.h b/arch/x86/boot/string.h
new file mode 100644
index 000000000000..725e820602b1
--- /dev/null
+++ b/arch/x86/boot/string.h
@@ -0,0 +1,21 @@
+#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);
+int memcmp(const void *s1, const void *s2, 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)
+#define memcmp	__builtin_memcmp
+
+#endif /* BOOT_STRING_H */
diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c
index 11e8c6eb80a1..ba3e100654db 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;