Re: [PATCH v6 3/3] selftests/lam: Update LAM tag width and cleanup names

[Sohil Mehta]

On 4/10/2026 2:55 AM, Maciej Wieczor-Retman wrote:
> diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c
> index 1919fa6daec0..f14600e74d8c 100644
> --- a/tools/testing/selftests/x86/lam.c
> +++ b/tools/testing/selftests/x86/lam.c
> @@ -24,11 +24,15 @@
>  # error This test is 64-bit only
>  #endif
>  
> +#define GENMASK(h, l) (((~0UL) << (l)) & (~0UL >> (__BITS_PER_LONG - 1 - (h))))
> +


Did you run into any problem when including linux/bits.h? It would be
preferable to avoid redefining generic macros. I see the GENMASK defines
in tools/include/linux/bits.h and include/uapi/linux/bits.h.

If you are running into issues with the x86 selftests header includes,
the uapi one should be safe to use.

You probably just need:
#define GENMASK(h, l)		__GENMASK(h, l)


>  /* LAM modes, these definitions were copied from kernel code */
>  #define LAM_NONE                0
> -#define LAM_U57_BITS            6
> +#define LAM_TAG_BITS		4
> +#define LAM_LS_BIT		57
> +#define LAM_MS_BIT		(LAM_LS_BIT + LAM_TAG_BITS - 1) /* 60 */
> +#define LAM_UNTAG_MASK		~GENMASK(LAM_MS_BIT, LAM_LS_BIT)
>  

Same comment as patch 1:
#define LAM_UNTAG_MASK		~GENMASK(60, 57)


> -#define LAM_U57_MASK            (0x3fULL << 57)
>  /* arch prctl for LAM */
>  #define ARCH_GET_UNTAG_MASK     0x4001
>  #define ARCH_ENABLE_TAGGED_ADDR 0x4002
> @@ -51,8 +55,8 @@
>  #define GET_USER_KERNEL         3

The rest of the patch looks fine.

With the above addressed,

Reviewed-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>