From 59aa31fd6f964ac63ac9cb90c8468f60e9bb0756 Mon Sep 17 00:00:00 2001 From: Ram Pai Date: Mon, 6 Nov 2017 00:50:45 -0800 Subject: [PATCH] powerpc: introduce pte_set_hidx() helper Introduce pte_set_hidx().It sets the (H_PAGE_F_SECOND|H_PAGE_F_GIX) bits at the appropriate location in the PTE of 4K PTE. For 64K PTE, it sets the bits in the second part of the PTE. Though the implementation for the former just needs the slot parameter, it does take some additional parameters to keep the prototype consistent. This function will be handy as we work towards re-arranging the bits in the subsequent patches. Acked-by: Balbir Singh Reviewed-by: Aneesh Kumar K.V Signed-off-by: Ram Pai Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/book3s/64/hash-4k.h | 14 +++++++++++ arch/powerpc/include/asm/book3s/64/hash-64k.h | 25 +++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h index 197ced1eaaa0..2975fc172d1a 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h @@ -49,6 +49,20 @@ static inline int hash__hugepd_ok(hugepd_t hpd) } #endif +/* + * 4K PTE format is different from 64K PTE format. Saving the hash_slot is just + * a matter of returning the PTE bits that need to be modified. On 64K PTE, + * things are a little more involved and hence needs many more parameters to + * accomplish the same. However we want to abstract this out from the caller by + * keeping the prototype consistent across the two formats. + */ +static inline unsigned long pte_set_hidx(pte_t *ptep, real_pte_t rpte, + unsigned int subpg_index, unsigned long hidx) +{ + return (hidx << H_PAGE_F_GIX_SHIFT) & + (H_PAGE_F_SECOND | H_PAGE_F_GIX); +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline char *get_hpte_slot_array(pmd_t *pmdp) diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h index 8d40cf03cb67..c1bd258b7303 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h @@ -68,6 +68,8 @@ static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep) return rpte; } +#define HIDX_BITS(x, index) (x << (index << 2)) + static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index) { if ((pte_val(rpte.pte) & H_PAGE_COMBO)) @@ -75,6 +77,29 @@ static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index) return (pte_val(rpte.pte) >> H_PAGE_F_GIX_SHIFT) & 0xf; } +/* + * Commit the hidx and return PTE bits that needs to be modified. The caller is + * expected to modify the PTE bits accordingly and commit the PTE to memory. + */ +static inline unsigned long pte_set_hidx(pte_t *ptep, real_pte_t rpte, + unsigned int subpg_index, unsigned long hidx) +{ + unsigned long *hidxp = (unsigned long *)(ptep + PTRS_PER_PTE); + + rpte.hidx &= ~HIDX_BITS(0xfUL, subpg_index); + *hidxp = rpte.hidx | HIDX_BITS(hidx, subpg_index); + + /* + * Anyone reading PTE must ensure hidx bits are read after reading the + * PTE by using the read-side barrier smp_rmb(). __real_pte() can be + * used for that. + */ + smp_wmb(); + + /* No PTE bits to be modified, return 0x0UL */ + return 0x0UL; +} + #define __rpte_to_pte(r) ((r).pte) extern bool __rpte_sub_valid(real_pte_t rpte, unsigned long index); /* -- 2.30.2