1 files changed, 33 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index 212004ec787d..3b5a82fc6ad7 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -11,3 +11,36 @@ int memcmp(const void *s1, const void *s2, size_t len)
 }
 
 #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