Re: [PATCH] xen/arm64: sysreg.h: Fix MISRA C 2012 Rule 20.7 violation

[Julien Grall <julien@xxxxxxx>]

Hi,

On 28/07/2022 14:49, Xenia Ragiadakou wrote:
> The macro parameter 'v' is used as an expression and needs to be enclosed in
> parentheses.
>
> Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
> ---
>   xen/arch/arm/include/asm/arm64/sysregs.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/include/asm/arm64/sysregs.h 
> b/xen/arch/arm/include/asm/arm64/sysregs.h
> index 54670084c3..f5a7269a27 100644
> --- a/xen/arch/arm/include/asm/arm64/sysregs.h
> +++ b/xen/arch/arm/include/asm/arm64/sysregs.h
> @@ -461,7 +461,7 @@
>   /* Access to system registers */
>   
>   #define WRITE_SYSREG64(v, name) do {                    \
> -    uint64_t _r = v;                                    \
> +    uint64_t _r = (v);                                              \
I am failing to see why the parentheses are necessary here. Could you 
give an example where the lack of them would end up to different code?
>       asm volatile("msr "__stringify(name)", %0" : : "r" (_r));       \
>   } while (0)
>   #define READ_SYSREG64(name) ({                          \
Cheers,

--
Julien Grall