libpayload: sync ARMv7 arch/io.h with coreboot

On ARMv7 we need to carefully add memory barriers to
all memory read and write operations. This change
brings libpayload in sync with what coreboot is doing.

Signed-off-by: Stefan Reinauer <>

Change-Id: Ie9c30b0f0d30531c5f9d99c2729246a86b8cec26
Reviewed-by: Gabe Black <>
Tested-by: Stefan Reinauer <>
Commit-Queue: Stefan Reinauer <>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <>
1 file changed