Re: [PATCH] clock: implement CLOCKSOURCE_MASK in terms of GENMASK_ULL

[Sascha Hauer <sha@pengutronix.de>]

On Tue, Apr 04, 2023 at 12:19:14PM +0200, Ahmad Fatoum wrote:
> Clang doesn't like our implementation of CLOCKSOURCE_MASK:
> 
>   common/clock.c:33:10: warning: shift count >= width of type [-Wshift-count-overflow]
> 	.mask = CLOCKSOURCE_MASK(64),
>                 ^~~~~~~~~~~~~~~~~~~~
>   include/clock.h:8:63: note: expanded from macro 'CLOCKSOURCE_MASK'
> 	 #define CLOCKSOURCE_MASK(bits) (uint64_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
> 
> So the bits < 64 check we have is apparently not enough to suppress the
> warning when built with clang.
> 
> Let's do what the kernel does and use GENMASK_ULL instead to get rid of
> the last remaining warning when building ARCH=sandbox targettools_defconfig
> with clang version 16.0.1.
> 
> Not functional change intended.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  include/clock.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/include/clock.h b/include/clock.h
> index 8e07c35d374e..03a38911a7a7 100644
> --- a/include/clock.h
> +++ b/include/clock.h
> @@ -4,8 +4,9 @@
>  
>  #include <types.h>
>  #include <linux/time.h>
> +#include <linux/bitops.h>
>  
> -#define CLOCKSOURCE_MASK(bits) (uint64_t)((bits) < 64 ? ((1ULL<<(bits))-1) : -1)
> +#define CLOCKSOURCE_MASK(bits) GENMASK_ULL((bits) - 1, 0)
>  
>  struct clocksource {
>  	uint32_t	shift;
> -- 
> 2.39.2
> 
> 
> 

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