Add faster, architecture dependent memcpy()

Change-Id: I38d15f3f1ec65f0cb7974d2dd4ae6356433bddd8
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: http://review.coreboot.org/736
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
Tested-by: build bot (Jenkins)

src/arch/x86/Kconfig

@@ -76,6 +76,10 @@ config CMOS_DEFAULT_FILE
 config BOOTBLOCK_SOUTHBRIDGE_INIT
 	string
 
+config HAVE_ARCH_MEMCPY
+	bool
+	default y
+
 config BIG_ENDIAN
 	bool
 	default n

src/arch/x86/lib/Makefile.inc

@@ -8,8 +8,12 @@ ramstage-$(CONFIG_MMCONF_SUPPORT) += pci_ops_mmconf.c
 ramstage-y += pci_ops_auto.c
 ramstage-y += exception.c
 ramstage-$(CONFIG_IOAPIC) += ioapic.c
+ramstage-y += memcpy.c
 
 romstage-y += romstage_console.c
 romstage-y += cbfs_and_run.c
+romstage-y += memcpy.c
+
+smm-y += memcpy.c
 
 $(obj)/arch/x86/lib/console.ramstage.o :: $(obj)/build.h

src/arch/x86/lib/memcpy.c

@@ -0,0 +1,13 @@
+#include <string.h>
+
+void *memcpy(void *__restrict __dest,
+	     __const void *__restrict __src, size_t __n)
+{
+	asm("cld\n"
+	    "rep\n"
+	    "movsb"
+	    :	/* no input (?) */
+	    :"S"(__src), "D"(__dest), "c"(__n)
+	);
+	return __dest;
+}