Re: [Xen-devel] [PATCH 3/7] Arm/atomic: correct asm() constraints in build_add_sized()

[Julien Grall <julien.grall@xxxxxxx>]

Hi Jan,

On 11/03/2019 16:49, Jan Beulich wrote:
> The memory operand is an in/out one, and the auxiliary register gets
> written to early.
>
> Take the opportunity and also drop the redundant cast (the inline
> functions' parameters are already of the casted-to type).
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
I guess this is candidate for backporting.

Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

> --- a/xen/include/asm-arm/atomic.h
> +++ b/xen/include/asm-arm/atomic.h
> @@ -30,7 +30,7 @@ static inline void name(volatile type *a
>       asm volatile("ldr" size " %"width"1,%0\n"                           \
>                    "add %"width"1,%"width"1,%"width"2\n"                  \
>                    "str" size " %"width"1,%0"                             \
> -                 : "=m" (*(volatile type *)addr), "=r" (t)              \
> +                 : "+m" (*addr), "=&r" (t)                              \
>                    : reg (val));                                          \
>   }
>   
--
Julien Grall

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