Re: [PATCH -next v4] arm64: fix build warning for ARM64_MEMSTART_SHIFT

[Catalin Marinas]

On Fri, Aug 04, 2023 at 03:56:15PM +0800, Zhang Jianhua wrote:
> When building with W=1, the following warning occurs.
> 
> arch/arm64/include/asm/kernel-pgtable.h:129:41: error: "PUD_SHIFT" is not defined, evaluates to 0 [-Werror=undef]
>   129 | #define ARM64_MEMSTART_SHIFT            PUD_SHIFT
>       |                                         ^~~~~~~~~
> arch/arm64/include/asm/kernel-pgtable.h:142:5: note: in expansion of macro ‘ARM64_MEMSTART_SHIFT’
>   142 | #if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
>       |     ^~~~~~~~~~~~~~~~~~~~
> 
> The generic PUD_SHIFT was defined in include/asm-generic/pgtable-nopud.h,
> however the #ifndef __ASSEMBLY__ guard in this header file makes it unavailable
> for assembly files. While someone .S file include the <asm/kernel-pgtable.h>,
> the build warning would occur. Now move the macro ARM64_MEMSTART_SHIFT and
> ARM64_MEMSTART_ALIGN to arch/arm64/mm/init.c where it is used only, to avoid
> this issue.
> 
> Signed-off-by: Zhang Jianhua <chris.zjh@xxxxxxxxxx>

Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>