[PATCH v9 2/7] powerpc: mm: Implement p{m,u,4}d_leaf on all platforms

[Christophe Leroy]

Le 30/11/2023 à 03:53, Rohan McLure a écrit :
> The check that a higher-level entry in multi-level pages contains a page
> translation entry (pte) is performed by p{m,u,4}d_leaf stubs, which may
> be specialised for each choice of mmu. In a prior commit, we replace
> uses to the catch-all stubs, p{m,u,4}d_is_leaf with p{m,u,4}d_leaf.
> 
> Replace the catch-all stub definitions for p{m,u,4}d_is_leaf with
> definitions for p{m,u,4}d_leaf. A future patch will assume that
> p{m,u,4}d_leaf is defined on all platforms.
> 
> In particular, implement pud_leaf for Book3E-64, pmd_leaf for all Book3E
> and Book3S-64 platforms, with a catch-all definition for p4d_leaf.

Is that needed ? There are fallback definitions of all pXd_leaf() in 
include/linux/pgtable.h

> 
> Reviewed-by: Christophe Leroy <christophe.leroy at csgroup.eu>
> Signed-off-by: Rohan McLure <rmclure at linux.ibm.com>
> ---
> v9: No longer required in order implement page table check, just
> refactoring.
> ---
>   arch/powerpc/include/asm/book3s/32/pgtable.h |  5 +++++
>   arch/powerpc/include/asm/book3s/64/pgtable.h | 10 ++++-----
>   arch/powerpc/include/asm/nohash/64/pgtable.h |  6 ++++++
>   arch/powerpc/include/asm/pgtable.h           | 22 ++------------------
>   4 files changed, 17 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
> index 52971ee30717..9cc95a61d2a6 100644
> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
> @@ -223,6 +223,11 @@ static inline void pmd_clear(pmd_t *pmdp)
>   	*pmdp = __pmd(0);
>   }
>   
> +#define pmd_leaf pmd_leaf
> +static inline bool pmd_leaf(pmd_t pmd)
> +{
> +	return false;
> +}

Is that needed ? There is a fallback definition of pmd_leaf() in 
include/linux/pgtable.h

>   
>   /*
>    * When flushing the tlb entry for a page, we also need to flush the hash
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index cb77eddca54b..8fdb7667c509 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -1459,16 +1459,14 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va
>   /*
>    * Like pmd_huge() and pmd_large(), but works regardless of config options
>    */
> -#define pmd_is_leaf pmd_is_leaf
> -#define pmd_leaf pmd_is_leaf
> -static inline bool pmd_is_leaf(pmd_t pmd)
> +#define pmd_leaf pmd_leaf
> +static inline bool pmd_leaf(pmd_t pmd)
>   {
>   	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
>   }
>   
> -#define pud_is_leaf pud_is_leaf
> -#define pud_leaf pud_is_leaf
> -static inline bool pud_is_leaf(pud_t pud)
> +#define pud_leaf pud_leaf
> +static inline bool pud_leaf(pud_t pud)
>   {
>   	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
>   }
> diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
> index 2202c78730e8..f58cbebde26e 100644
> --- a/arch/powerpc/include/asm/nohash/64/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
> @@ -116,6 +116,12 @@ static inline void pud_clear(pud_t *pudp)
>   	*pudp = __pud(0);
>   }
>   
> +#define pud_leaf pud_leaf
> +static inline bool pud_leaf(pud_t pud)
> +{
> +	return false;
> +}
> +

Is that needed ? There is a fallback definition of pud_leaf() in 
include/linux/pgtable.h

>   #define pud_none(pud)		(!pud_val(pud))
>   #define	pud_bad(pud)		(!is_kernel_addr(pud_val(pud)) \
>   				 || (pud_val(pud) & PUD_BAD_BITS))
> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index 9224f23065ff..db0231afca9d 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -180,29 +180,11 @@ static inline void pte_frag_set(mm_context_t *ctx, void *p)
>   }
>   #endif
>   
> -#ifndef pmd_is_leaf
> -#define pmd_is_leaf pmd_is_leaf
> -static inline bool pmd_is_leaf(pmd_t pmd)
> +#define p4d_leaf p4d_leaf
> +static inline bool p4d_leaf(p4d_t p4d)
>   {
>   	return false;
>   }

Is that needed ? There is a fallback definition of p4d_leaf() in 
include/linux/pgtable.h

> -#endif
> -
> -#ifndef pud_is_leaf
> -#define pud_is_leaf pud_is_leaf
> -static inline bool pud_is_leaf(pud_t pud)
> -{
> -	return false;
> -}
> -#endif
> -
> -#ifndef p4d_is_leaf
> -#define p4d_is_leaf p4d_is_leaf
> -static inline bool p4d_is_leaf(p4d_t p4d)
> -{
> -	return false;
> -}
> -#endif
>   
>   #define pmd_pgtable pmd_pgtable
>   static inline pgtable_t pmd_pgtable(pmd_t pmd)