hg: jdk/sandbox: 8211387: [Zero] atomic_copy64: Use ldrexd for atomic reads on ARMv7

[chris.hegarty at oracle.com]

Changeset: 6ee9500fe653
Author:    sgehwolf
Date:      2018-10-02 17:17 +0200
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/6ee9500fe653

8211387: [Zero] atomic_copy64: Use ldrexd for atomic reads on ARMv7
Reviewed-by: dholmes, aph
Contributed-by: Andrew Haley <aph at redhat.com>

! src/hotspot/os_cpu/linux_zero/os_linux_zero.hpp