arch/x86: Add atomic_set() and memory barriers

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/x86: Use atomic_set() in spinlock implementation

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/arm: Fix build

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/x86: Fix {disable,restore}_interrupts()

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/x86[_64]: Add cpu_{stop,pause}()

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
kernel/um: Add cpu_{stop,pause}() and interrupt routines

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/arm: Add cpu_{stop,pause}() and interrupt routines

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>