[PATCH v4 03/29] mm: use ARCH_PKEY_BITS to define VM_PKEY_BITN

[Anshuman Khandual]

On 5/3/24 18:31, Joey Gouly wrote:
> Use the new CONFIG_ARCH_PKEY_BITS to simplify setting these bits
> for different architectures.
> 
> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> 
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: linux-fsdevel at vger.kernel.org
> Cc: linux-mm at kvack.org
> ---
>  fs/proc/task_mmu.c |  2 ++
>  include/linux/mm.h | 16 ++++++++++------
>  2 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 23fbab954c20..0d152f460dcc 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -692,7 +692,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
>  		[ilog2(VM_PKEY_BIT0)]	= "",
>  		[ilog2(VM_PKEY_BIT1)]	= "",
>  		[ilog2(VM_PKEY_BIT2)]	= "",
> +#if VM_PKEY_BIT3
>  		[ilog2(VM_PKEY_BIT3)]	= "",
> +#endif
>  #if VM_PKEY_BIT4
>  		[ilog2(VM_PKEY_BIT4)]	= "",
>  #endif
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b6bdaa18b9e9..5605b938acce 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -329,12 +329,16 @@ extern unsigned int kobjsize(const void *objp);
>  #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
>  
>  #ifdef CONFIG_ARCH_HAS_PKEYS
> -# define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
> -# define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
> -# define VM_PKEY_BIT1	VM_HIGH_ARCH_1	/* on x86 and 5-bit value on ppc64   */
> -# define VM_PKEY_BIT2	VM_HIGH_ARCH_2
> -# define VM_PKEY_BIT3	VM_HIGH_ARCH_3
> -#ifdef CONFIG_PPC
> +# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
> +# define VM_PKEY_BIT0  VM_HIGH_ARCH_0
> +# define VM_PKEY_BIT1  VM_HIGH_ARCH_1
> +# define VM_PKEY_BIT2  VM_HIGH_ARCH_2
> +#if CONFIG_ARCH_PKEY_BITS > 3
> +# define VM_PKEY_BIT3  VM_HIGH_ARCH_3
> +#else
> +# define VM_PKEY_BIT3  0
> +#endif
> +#if CONFIG_ARCH_PKEY_BITS > 4
>  # define VM_PKEY_BIT4  VM_HIGH_ARCH_4
>  #else
>  # define VM_PKEY_BIT4  0

Agree with Dave that this is not very clean but does the job i.e getting
rid of the platform #ifdef which in itself is an improvement.

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>