On Thu, Oct 18, 2018 at 05:04:34PM +0200, Daniel Borkmann wrote:
> #endif /* _TOOLS_LINUX_ASM_IA64_BARRIER_H */
> diff --git a/tools/arch/powerpc/include/asm/barrier.h
> b/tools/arch/powerpc/include/asm/barrier.h
> index a634da0..905a2c6 100644
> --- a/tools/arch/powerpc/include/asm/barrier.h
> +++ b/tools/arch/powerpc/include/asm/barrier.h
> @@ -27,4 +27,20 @@
> #define rmb() __asm__ __volatile__ ("sync" : : : "memory")
> #define wmb() __asm__ __volatile__ ("sync" : : : "memory")
>
> +#if defined(__powerpc64__)
> +#define smp_lwsync() __asm__ __volatile__ ("lwsync" : : : "memory")
> +
> +#define smp_store_release(p, v) \
> +do { \
> + smp_lwsync(); \
> + WRITE_ONCE(*p, v); \
> +} while (0)
> +
> +#define smp_load_acquire(p) \
> +({ \
> + typeof(*p) ___p1 = READ_ONCE(*p); \
> + smp_lwsync(); \
> + ___p1; \
I don't like this proliferation of asm.
Why do we think that we can do better job than compiler?
can we please use gcc builtins instead?
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
__atomic_load_n(ptr, __ATOMIC_ACQUIRE);
__atomic_store_n(ptr, val, __ATOMIC_RELEASE);
are done specifically for this use case if I'm not mistaken.
I think it pays to learn what compiler provides.
