From bf9a95f9a6481bc6ec98ef7b328c14177eeb3492 Mon Sep 17 00:00:00 2001 From: Ram Pai Date: Mon, 6 Nov 2017 00:50:48 -0800 Subject: [PATCH] powerpc: Free up four 64K PTE bits in 64K backed HPTE pages Rearrange 64K PTE bits to free up bits 3, 4, 5 and 6 in the 64K backed HPTE pages. This along with the earlier patch will entirely free up the four bits from 64K PTE. The bit numbers are big-endian as defined in the ISA3.0 This patch does the following change to 64K PTE backed by 64K HPTE. H_PAGE_F_SECOND (S) which occupied bit 4 moves to the second part of the pte to bit 60. H_PAGE_F_GIX (G,I,X) which occupied bit 5, 6 and 7 also moves to the second part of the pte to bit 61, 62, 63, 64 respectively since bit 7 is now freed up, we move H_PAGE_BUSY (B) from bit 9 to bit 7. The second part of the PTE will hold (H_PAGE_F_SECOND|H_PAGE_F_GIX) at bit 60,61,62,63. NOTE: None of the bits in the secondary PTE were not used by 64k-HPTE backed PTE. Before the patch, the 64K HPTE backed 64k PTE format was as follows 0 1 2 3 4 5 6 7 8 9 10...........................63 : : : : : : : : : : : : v v v v v v v v v v v v ,-,-,-,-,--,--,--,--,-,-,-,-,-,------------------,-,-,-, |x|x|x| |S |G |I |X |x|B| |x|x|................|x|x|x|x| <- primary pte '_'_'_'_'__'__'__'__'_'_'_'_'_'________________'_'_'_'_' | | | | | | | | | | | | |..................| | | | | <- secondary pte '_'_'_'_'__'__'__'__'_'_'_'_'__________________'_'_'_'_' After the patch, the 64k HPTE backed 64k PTE format is as follows 0 1 2 3 4 5 6 7 8 9 10...........................63 : : : : : : : : : : : : v v v v v v v v v v v v ,-,-,-,-,--,--,--,--,-,-,-,-,-,------------------,-,-,-, |x|x|x| | | | |B |x| | |x|x|................|.|.|.|.| <- primary pte '_'_'_'_'__'__'__'__'_'_'_'_'_'________________'_'_'_'_' | | | | | | | | | | | | |..................|S|G|I|X| <- secondary pte '_'_'_'_'__'__'__'__'_'_'_'_'__________________'_'_'_'_' The above PTE changes is applicable to hugetlbpages aswell. The patch does the following code changes: a) moves the H_PAGE_F_SECOND and H_PAGE_F_GIX to 4k PTE header since it is no more needed b the 64k PTEs. b) abstracts out __real_pte() and __rpte_to_hidx() so the caller need not know the bit location of the slot. c) moves the slot bits to the secondary pte. 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 | 3 ++ arch/powerpc/include/asm/book3s/64/hash-64k.h | 30 +++++++++---------- arch/powerpc/include/asm/book3s/64/hash.h | 3 -- arch/powerpc/mm/hash64_64k.c | 21 +++++++------ arch/powerpc/mm/hugetlbpage-hash64.c | 16 ++++------ 5 files changed, 33 insertions(+), 40 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h index e0130c34766e..ed0d1cd98907 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h @@ -17,6 +17,9 @@ #define H_PUD_TABLE_SIZE (sizeof(pud_t) << H_PUD_INDEX_SIZE) #define H_PGD_TABLE_SIZE (sizeof(pgd_t) << H_PGD_INDEX_SIZE) +#define H_PAGE_F_GIX_SHIFT 56 +#define H_PAGE_F_SECOND _RPAGE_RSV2 /* HPTE is in 2ndary HPTEG */ +#define H_PAGE_F_GIX (_RPAGE_RSV3 | _RPAGE_RSV4 | _RPAGE_RPN44) #define H_PAGE_BUSY _RPAGE_RSV1 /* software: PTE & hash are busy */ /* PTE flags to conserve for HPTE identification */ diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h index c929e6437a60..73ed988e6da5 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h @@ -13,7 +13,7 @@ */ #define H_PAGE_COMBO _RPAGE_RPN0 /* this is a combo 4k page */ #define H_PAGE_4K_PFN _RPAGE_RPN1 /* PFN is for a single 4k page */ -#define H_PAGE_BUSY _RPAGE_RPN42 /* software: PTE & hash are busy */ +#define H_PAGE_BUSY _RPAGE_RPN44 /* software: PTE & hash are busy */ /* * We need to differentiate between explicit huge page and THP huge @@ -22,8 +22,7 @@ #define H_PAGE_THP_HUGE H_PAGE_4K_PFN /* PTE flags to conserve for HPTE identification */ -#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_F_SECOND | \ - H_PAGE_F_GIX | H_PAGE_HASHPTE | H_PAGE_COMBO) +#define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_HASHPTE | H_PAGE_COMBO) /* * we support 16 fragments per PTE page of 64K size. */ @@ -51,27 +50,26 @@ static inline real_pte_t __real_pte(pte_t pte, pte_t *ptep) unsigned long *hidxp; rpte.pte = pte; - rpte.hidx = 0; - if (pte_val(pte) & H_PAGE_COMBO) { - /* - * Make sure we order the hidx load against the H_PAGE_COMBO - * check. The store side ordering is done in __hash_page_4K - */ - smp_rmb(); - hidxp = (unsigned long *)(ptep + PTRS_PER_PTE); - rpte.hidx = *hidxp; - } + + /* + * Ensure that we do not read the hidx before we read the PTE. Because + * the writer side is expected to finish writing the hidx first followed + * by the PTE, by using smp_wmb(). pte_set_hash_slot() ensures that. + */ + smp_rmb(); + + hidxp = (unsigned long *)(ptep + PTRS_PER_PTE); + rpte.hidx = *hidxp; return rpte; } #define HIDX_BITS(x, index) (x << (index << 2)) +#define BITS_TO_HIDX(x, index) ((x >> (index << 2)) & 0xfUL) #define INVALID_RPTE_HIDX ~(0x0UL) static inline unsigned long __rpte_to_hidx(real_pte_t rpte, unsigned long index) { - if ((pte_val(rpte.pte) & H_PAGE_COMBO)) - return (rpte.hidx >> (index<<2)) & 0xf; - return (pte_val(rpte.pte) >> H_PAGE_F_GIX_SHIFT) & 0xf; + return BITS_TO_HIDX(rpte.hidx, index); } /* diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index 4e19a612a963..e72474f13936 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -9,9 +9,6 @@ * */ #define H_PTE_NONE_MASK _PAGE_HPTEFLAGS -#define H_PAGE_F_GIX_SHIFT 56 -#define H_PAGE_F_SECOND _RPAGE_RSV2 /* HPTE is in 2ndary HPTEG */ -#define H_PAGE_F_GIX (_RPAGE_RSV3 | _RPAGE_RSV4 | _RPAGE_RPN44) #define H_PAGE_HASHPTE _RPAGE_RPN43 /* PTE has associated HPTE */ #ifdef CONFIG_PPC_64K_PAGES diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c index b79f50c693cf..2253bbc6a599 100644 --- a/arch/powerpc/mm/hash64_64k.c +++ b/arch/powerpc/mm/hash64_64k.c @@ -103,8 +103,8 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, * On hash insert failure we use old pte value and we don't * want slot information there if we have a insert failure. */ - old_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND); - new_pte &= ~(H_PAGE_HASHPTE | H_PAGE_F_GIX | H_PAGE_F_SECOND); + old_pte &= ~H_PAGE_HASHPTE; + new_pte &= ~H_PAGE_HASHPTE; goto htab_insert_hpte; } /* @@ -225,6 +225,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access, unsigned long vsid, pte_t *ptep, unsigned long trap, unsigned long flags, int ssize) { + real_pte_t rpte; unsigned long hpte_group; unsigned long rflags, pa; unsigned long old_pte, new_pte; @@ -261,6 +262,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access, } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); rflags = htab_convert_pte_flags(new_pte); + rpte = __real_pte(__pte(old_pte), ptep); if (cpu_has_feature(CPU_FTR_NOEXECUTE) && !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) @@ -268,16 +270,13 @@ int __hash_page_64K(unsigned long ea, unsigned long access, vpn = hpt_vpn(ea, vsid, ssize); if (unlikely(old_pte & H_PAGE_HASHPTE)) { + unsigned long gslot; + /* * There MIGHT be an HPTE for this pte */ - hash = hpt_hash(vpn, shift, ssize); - if (old_pte & H_PAGE_F_SECOND) - hash = ~hash; - slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; - slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; - - if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_64K, + gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0); + if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, MMU_PAGE_64K, MMU_PAGE_64K, ssize, flags) == -1) old_pte &= ~_PAGE_HPTEFLAGS; @@ -326,9 +325,9 @@ repeat: MMU_PAGE_64K, MMU_PAGE_64K, old_pte); return -1; } + new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | H_PAGE_HASHPTE; - new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & - (H_PAGE_F_SECOND | H_PAGE_F_GIX); + new_pte |= pte_set_hidx(ptep, rpte, 0, slot); } *ptep = __pte(new_pte & ~H_PAGE_BUSY); return 0; diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c index 0c2a91df3210..12511f5a015f 100644 --- a/arch/powerpc/mm/hugetlbpage-hash64.c +++ b/arch/powerpc/mm/hugetlbpage-hash64.c @@ -23,6 +23,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, pte_t *ptep, unsigned long trap, unsigned long flags, int ssize, unsigned int shift, unsigned int mmu_psize) { + real_pte_t rpte; unsigned long vpn; unsigned long old_pte, new_pte; unsigned long rflags, pa, sz; @@ -62,6 +63,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, } while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); rflags = htab_convert_pte_flags(new_pte); + rpte = __real_pte(__pte(old_pte), ptep); sz = ((1UL) << shift); if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) @@ -72,15 +74,10 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, /* Check if pte already has an hpte (case 2) */ if (unlikely(old_pte & H_PAGE_HASHPTE)) { /* There MIGHT be an HPTE for this pte */ - unsigned long hash, slot; + unsigned long gslot; - hash = hpt_hash(vpn, shift, ssize); - if (old_pte & H_PAGE_F_SECOND) - hash = ~hash; - slot = (hash & htab_hash_mask) * HPTES_PER_GROUP; - slot += (old_pte & H_PAGE_F_GIX) >> H_PAGE_F_GIX_SHIFT; - - if (mmu_hash_ops.hpte_updatepp(slot, rflags, vpn, mmu_psize, + gslot = pte_get_hash_gslot(vpn, shift, ssize, rpte, 0); + if (mmu_hash_ops.hpte_updatepp(gslot, rflags, vpn, mmu_psize, mmu_psize, ssize, flags) == -1) old_pte &= ~_PAGE_HPTEFLAGS; } @@ -107,8 +104,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, return -1; } - new_pte |= (slot << H_PAGE_F_GIX_SHIFT) & - (H_PAGE_F_SECOND | H_PAGE_F_GIX); + new_pte |= pte_set_hidx(ptep, rpte, 0, slot); } /*