Re: [RFC PATCH 1/5] powerpc/64s: update_mmu_cache inline the radix test

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 20/12/2020 à 00:48, Nicholas Piggin a écrit :
> This allows the function to be entirely noped if hash support is
> compiled out (not possible yet).
> 
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   arch/powerpc/include/asm/book3s/pgtable.h | 11 ++++++++++-
>   arch/powerpc/mm/book3s32/mmu.c            |  4 ++--
>   arch/powerpc/mm/book3s64/hash_utils.c     |  7 ++-----
>   3 files changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/pgtable.h b/arch/powerpc/include/asm/book3s/pgtable.h
> index 0e1263455d73..914e9fc7b069 100644
> --- a/arch/powerpc/include/asm/book3s/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/pgtable.h
> @@ -35,7 +35,16 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
>    * corresponding HPTE into the hash table ahead of time, instead of
>    * waiting for the inevitable extra hash-table miss exception.
>    */
> -void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep);
> +void hash__update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep);
> +
> +static inline void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
> +{
> +#ifdef CONFIG_PPC64

You shouldn't need that ifdef. radix_enabled() is always defined.

> +	if (radix_enabled())
> +		return;
> +#endif
> +	hash__update_mmu_cache(vma, address, ptep);
> +}
>   
>   #endif /* __ASSEMBLY__ */
>   #endif
> diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
> index 859e5bd603ac..c5a570ca37ff 100644
> --- a/arch/powerpc/mm/book3s32/mmu.c
> +++ b/arch/powerpc/mm/book3s32/mmu.c
> @@ -325,8 +325,8 @@ static void hash_preload(struct mm_struct *mm, unsigned long ea)
>    *
>    * This must always be called with the pte lock held.
>    */
> -void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
> -		      pte_t *ptep)
> +void hash__update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
> +			    pte_t *ptep)

Now the limit is 100 chars per line. This should fit on a single line I think.

>   {
>   	if (!mmu_has_feature(MMU_FTR_HPTE_TABLE))
>   		return;
> diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
> index 73b06adb6eeb..d52a3dee7cf2 100644
> --- a/arch/powerpc/mm/book3s64/hash_utils.c
> +++ b/arch/powerpc/mm/book3s64/hash_utils.c
> @@ -1667,8 +1667,8 @@ static void hash_preload(struct mm_struct *mm, pte_t *ptep, unsigned long ea,
>    *
>    * This must always be called with the pte lock held.
>    */
> -void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
> -		      pte_t *ptep)
> +void hash__update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
> +			    pte_t *ptep)

Now the limit is 100 chars per line. This should fit on a single line I think.

>   {
>   	/*
>   	 * We don't need to worry about _PAGE_PRESENT here because we are
> @@ -1677,9 +1677,6 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
>   	unsigned long trap;
>   	bool is_exec;
>   
> -	if (radix_enabled())
> -		return;
> -
>   	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
>   	if (!pte_young(*ptep) || address >= TASK_SIZE)
>   		return;
>