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SubjectRe: [RFC v6 04/62] powerpc: introduce pte_get_hash_gslot() helper
Date
Ram Pai <linuxram@us.ibm.com> writes:

> Introduce pte_get_hash_gslot()() which returns the slot number of the
> HPTE in the global hash table.
>
> This function will come in handy as we work towards re-arranging the
> PTE bits in the later patches.
>

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

> Signed-off-by: Ram Pai <linuxram@us.ibm.com>
> ---
> arch/powerpc/include/asm/book3s/64/hash.h | 3 +++
> arch/powerpc/mm/hash_utils_64.c | 18 ++++++++++++++++++
> 2 files changed, 21 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
> index d27f885..277158c 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash.h
> @@ -156,6 +156,9 @@ static inline int hash__pte_none(pte_t pte)
> return (pte_val(pte) & ~H_PTE_NONE_MASK) == 0;
> }
>
> +unsigned long pte_get_hash_gslot(unsigned long vpn, unsigned long shift,
> + int ssize, real_pte_t rpte, unsigned int subpg_index);
> +
> /* This low level function performs the actual PTE insertion
> * Setting the PTE depends on the MMU type and other factors. It's
> * an horrible mess that I'm not going to try to clean up now but
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index 1b494d0..d3604da 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -1591,6 +1591,24 @@ static inline void tm_flush_hash_page(int local)
> }
> #endif
>
> +/*
> + * return the global hash slot, corresponding to the given
> + * pte, which contains the hpte.
> + */
> +unsigned long pte_get_hash_gslot(unsigned long vpn, unsigned long shift,
> + int ssize, real_pte_t rpte, unsigned int subpg_index)
> +{
> + unsigned long hash, slot, hidx;
> +
> + hash = hpt_hash(vpn, shift, ssize);
> + hidx = __rpte_to_hidx(rpte, subpg_index);
> + if (hidx & _PTEIDX_SECONDARY)
> + hash = ~hash;
> + slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
> + slot += hidx & _PTEIDX_GROUP_IX;
> + return slot;
> +}
> +
> /* WARNING: This is called from hash_low_64.S, if you change this prototype,
> * do not forget to update the assembly call site !
> */
> --
> 1.7.1

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