arm64: use xzr to zero-out the bss section

AArch64 has a zero register (xzr).  Use it instead of x2.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
index 91b19e00da22cd12a68991cc40680de0736651ca..f8e84b2fc8b56342b03c2d2c01f84791a76bbd7c 100644 (file)
--- a/arch/arm/lib/crt0_64.S
+++ b/arch/arm/lib/crt0_64.S
@@ -117,9 +117,8 @@ relocation_return:
  */
        ldr     x0, =__bss_start                /* this is auto-relocated! */
        ldr     x1, =__bss_end                  /* this is auto-relocated! */
-       mov     x2, #0
 clear_loop:
-       str     x2, [x0]
+       str     xzr, [x0]
        add     x0, x0, #8
        cmp     x0, x1
        b.lo    clear_loop