[PATCH 2/3] sysdeps/arm/bits/atomic.h: Add a wider range of atomic operations

[Joseph S. Myers]

On Fri, 3 Oct 2014, Will Newton wrote:

> -# define __arch_compare_and_exchange_bool_64_int(mem, newval, oldval, model) \
> -  ({__arm_link_error (); 0; })
> +# define __arch_exchange_32_int(mem, newval, model)	\
> +  __atomic_exchange_n (mem, newval, model)

I think obvious link errors are desirable for 64-bit atomics, rather than 
possibly calling libatomic functions using locks, or libgcc functions that 
would introduce a hidden dependency on a more recent kernel version (for 
64-bit atomics helpers) than we currently require (the helpers having been 
introduced in 3.1).

(So in a generic header it should be configurable whether it provides 
64-bit atomic operations or not.)

-- 
Joseph S. Myers
joseph@codesourcery.com