Re: [PATCH] powerpc/mm/radix: Update Radix tree size as per ISA 3.0

[Balbir Singh <bsingharora@gmail.com>]

On 16/06/16 13:21, Aneesh Kumar K.V wrote:
> ISA 3.0 updated it to be encoded as Radix tree size = 2^(RTS + 31). We
> have it encoded as 2^(RTS + 28). Add a helper with the correct encoding
> and use it instead of opencoding.
> 
> Fixes commit 2bfd65e45e87 ("powerpc/mm/radix: Add radix callbacks for
> early init routine ")
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/64/radix.h | 15 +++++++++++++++
>  arch/powerpc/mm/mmu_context_book3s64.c     |  2 +-
>  arch/powerpc/mm/pgtable-radix.c            |  9 +++------
>  3 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
> index 0d980de55c40..cdf791af8ab2 100644
> --- a/arch/powerpc/include/asm/book3s/64/radix.h
> +++ b/arch/powerpc/include/asm/book3s/64/radix.h
> @@ -260,5 +260,20 @@ extern void radix__vmemmap_remove_mapping(unsigned long start,
>  
>  extern int radix__map_kernel_page(unsigned long ea, unsigned long pa,
>  				 pgprot_t flags, unsigned int psz);
> +
> +static inline unsigned long radix__get_rts_value(void)

How about radix__get_tree_size()?

> +{
> +	unsigned long rts_field;
> +	/*
> +	 * we support 52 bits, hence 52-31 = 21, 0b10101
> +	 * RTS encoding details
> +	 * bits 0 - 3 of rts -> bits 6 - 8 unsigned long
> +	 * bits 4 - 5 of rts -> bits 62 - 63 of unsigned long
> +	 */
> +	rts_field = (0x5UL << 5); /* 6 - 8 bits */
> +	rts_field |= (0x2UL << 61);
> +
> +	return rts_field;
> +}


Looks good otherwise

Reviewed-by: Balbir Singh <bsingharora@gmail.com>