x86, efi: Fix processor-specific memcpy() build error

Building for Athlon/Duron/K7 results in the following build error,

arch/x86/boot/compressed/eboot.o: In function `__constant_memcpy3d':
eboot.c:(.text+0x385): undefined reference to `_mmx_memcpy'
arch/x86/boot/compressed/eboot.o: In function `efi_main':
eboot.c:(.text+0x1a22): undefined reference to `_mmx_memcpy'

because the boot stub code doesn't link with the kernel proper, and
therefore doesn't have access to the 3DNow version of memcpy. So,
follow the example of misc.c and #undef memcpy so that we use the
version provided by misc.c.

See https://bugzilla.kernel.org/show_bug.cgi?id=50391

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Ryan Underwood <nemesis@icequake.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: stable@vger.kernel.org
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c760e073963e..e87b0cac14b5 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -12,6 +12,8 @@
 #include <asm/setup.h>
 #include <asm/desc.h>
 
+#undef memcpy                   /* Use memcpy from misc.c */
+
 #include "eboot.h"
 
 static efi_system_table_t *sys_table;