Re: [PATCH 2/2] powerpc/mm/64s: Drop p4d_leaf()

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

Michael Ellerman <mpe@ellerman.id.au> writes:

>
> Because 64-bit Book3S uses pgtable-nop4d.h, the P4D is folded into the
> PGD. So P4D entries are actually PGD entries, or vice versa.
>
> The other way to think of it is that the P4D is a single entry page
> table below the PGD. Zero bits of the address are needed to index into
> the P4D, therefore a P4D entry maps the same size address space as a PGD
> entry.
>
> As explained in the previous commit, there are no huge page sizes
> supported directly at the PGD level on 64-bit Book3S, so there are also
> no huge page sizes supported at the P4D level.
>
> Therefore p4d_is_leaf() can never be true, so drop the definition and
> fallback to the default implementation that always returns false.
>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  arch/powerpc/include/asm/book3s/64/pgtable.h | 7 -------
>  1 file changed, 7 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 486902aff040..057254063e88 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -1459,12 +1459,5 @@ static inline bool pud_is_leaf(pud_t pud)
>  	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>  }
>  
> -#define p4d_is_leaf p4d_is_leaf
> -#define p4d_leaf p4d_is_leaf
> -static inline bool p4d_is_leaf(p4d_t p4d)
> -{
> -	return !!(p4d_raw(p4d) & cpu_to_be64(_PAGE_PTE));
> -}
> -
>  #endif /* __ASSEMBLY__ */
>  #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
> -- 
> 2.37.2