Re: [PATCH v4 11/21] arm64: gpr-num: add __GPR_NUM() helper

[Vladimir Murzin <vladimir.murzin@arm.com>]

On 9/8/26 16:17, Mark Rutland wrote:
> The gpr-num infrastructure requires users to concatenate the register
> name with a long prefix in order to get a symbol that evaluates to a
> compile-time constant. Doing this manually is error-prone and painful to
> read.
> 
> Add a new __GPR_NUM() helper which wraps the concatenation.
> 
> For the moment I've left existing open-coded concatenation as-is. In
> particular, the DEFINE_MRS_S() and DEFINE_MSR_S() macros have awkward
> stringification requirements and would require invasive changes that
> outweigh the benefit. I have plans to rework those in the near future to
> remove the need to use gpr-num values.
> 
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
> Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: James Morse <james.morse@arm.com>
> Cc: Jinjie Ruan <ruanjinjie@huawei.com>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Vladimir Murzin <vladimir.murzin@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Yang Shi <yang@os.amperecomputing.com>
> ---
>  arch/arm64/include/asm/gpr-num.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/gpr-num.h b/arch/arm64/include/asm/gpr-num.h
> index 240cd25d55c5a..30fb8a67b19f0 100644
> --- a/arch/arm64/include/asm/gpr-num.h
> +++ b/arch/arm64/include/asm/gpr-num.h
> @@ -11,6 +11,8 @@
>  	.equ	.L__gpr_num_xzr, 31
>  	.equ	.L__gpr_num_wzr, 31
>  
> +#define __GPR_NUM(gpr)		(.L__gpr_num_##gpr)
> +
>  #else /* __ASSEMBLER__ */
>  
>  #define __DEFINE_ASM_GPR_NUMS					\
> @@ -26,6 +28,8 @@
>  "	wx\\n	.req	w\\n\n"										\
>  "	.endr\n"
>  
> +#define __GPR_NUM(gpr)		"(.L__gpr_num_" gpr ")"
> +
>  #endif /* __ASSEMBLER__ */
>  
>  #endif /* __ASM_GPR_NUM_H */
> -- 2.30.2
> 

Brilliant!

FWIW,

Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>