From 41743a4e34f0777f51c1cf0675b91508ba143050 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 11 Jun 2008 15:37:10 +1000 Subject: [PATCH] powerpc: Free a PTE bit on ppc64 with 64K pages This frees a PTE bit when using 64K pages on ppc64. This is done by getting rid of the separate _PAGE_HASHPTE bit. Instead, we just test if any of the 16 sub-page bits is set. For non-combo pages (ie. real 64K pages), we set SUB0 and the location encoding in that field. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/mm/hash_low_64.S | 17 ++++++++++------- arch/powerpc/mm/hugetlbpage.c | 8 +++++--- include/asm-powerpc/pgtable-4k.h | 1 + include/asm-powerpc/pgtable-64k.h | 17 +++++++++++++++-- include/asm-powerpc/pgtable-ppc64.h | 1 - 5 files changed, 31 insertions(+), 13 deletions(-) diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S index 70f4c833fa32..a719f53921a5 100644 --- a/arch/powerpc/mm/hash_low_64.S +++ b/arch/powerpc/mm/hash_low_64.S @@ -388,7 +388,7 @@ _GLOBAL(__hash_page_4K) */ rlwinm r30,r4,32-9+7,31-7,31-7 /* _PAGE_RW -> _PAGE_DIRTY */ or r30,r30,r31 - ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE + ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED oris r30,r30,_PAGE_COMBO@h /* Write the linux PTE atomically (setting busy) */ stdcx. r30,0,r6 @@ -468,7 +468,7 @@ END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE) * go to out-of-line code to try to modify the HPTE. We look for * the bit at (1 >> (index + 32)) */ - andi. r0,r31,_PAGE_HASHPTE + rldicl. r0,r31,64-12,48 li r26,0 /* Default hidx */ beq htab_insert_pte @@ -726,11 +726,11 @@ BEGIN_FTR_SECTION bne- ht64_bail_ok END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE) /* Prepare new PTE value (turn access RW into DIRTY, then - * add BUSY,HASHPTE and ACCESSED) + * add BUSY and ACCESSED) */ rlwinm r30,r4,32-9+7,31-7,31-7 /* _PAGE_RW -> _PAGE_DIRTY */ or r30,r30,r31 - ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE + ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED /* Write the linux PTE atomically (setting busy) */ stdcx. r30,0,r6 bne- 1b @@ -798,18 +798,21 @@ END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE) /* Check if we may already be in the hashtable, in this case, we * go to out-of-line code to try to modify the HPTE */ - andi. r0,r31,_PAGE_HASHPTE + rldicl. r0,r31,64-12,48 bne ht64_modify_pte ht64_insert_pte: /* Clear hpte bits in new pte (we also clear BUSY btw) and - * add _PAGE_HASHPTE + * add _PAGE_HPTE_SUB0 */ lis r0,_PAGE_HPTEFLAGS@h ori r0,r0,_PAGE_HPTEFLAGS@l andc r30,r30,r0 +#ifdef CONFIG_PPC_64K_PAGES + oris r30,r30,_PAGE_HPTE_SUB0@h +#else ori r30,r30,_PAGE_HASHPTE - +#endif /* Phyical address in r5 */ rldicl r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT sldi r5,r5,PAGE_SHIFT diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index a02266dad215..8fa07f3f6c2b 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -458,8 +458,7 @@ int hash_huge_page(struct mm_struct *mm, unsigned long access, old_pte = pte_val(*ptep); if (old_pte & _PAGE_BUSY) goto out; - new_pte = old_pte | _PAGE_BUSY | - _PAGE_ACCESSED | _PAGE_HASHPTE; + new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED; } while(old_pte != __cmpxchg_u64((unsigned long *)ptep, old_pte, new_pte)); @@ -499,8 +498,11 @@ repeat: HPTES_PER_GROUP) & ~0x7UL; /* clear HPTE slot informations in new PTE */ +#ifdef CONFIG_PPC_64K_PAGES + new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0; +#else new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE; - +#endif /* Add in WIMG bits */ /* XXX We should store these in the pte */ /* --BenH: I think they are ... */ diff --git a/include/asm-powerpc/pgtable-4k.h b/include/asm-powerpc/pgtable-4k.h index 818e2abc81e2..fd2090dc1dce 100644 --- a/include/asm-powerpc/pgtable-4k.h +++ b/include/asm-powerpc/pgtable-4k.h @@ -41,6 +41,7 @@ #define PGDIR_MASK (~(PGDIR_SIZE-1)) /* PTE bits */ +#define _PAGE_HASHPTE 0x0400 /* software: pte has an associated HPTE */ #define _PAGE_SECONDARY 0x8000 /* software: HPTE is in secondary group */ #define _PAGE_GROUP_IX 0x7000 /* software: HPTE index within group */ #define _PAGE_F_SECOND _PAGE_SECONDARY diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h index 1cbd6b377eea..c5007712473f 100644 --- a/include/asm-powerpc/pgtable-64k.h +++ b/include/asm-powerpc/pgtable-64k.h @@ -75,6 +75,20 @@ static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd) #define _PAGE_COMBO 0x10000000 /* this is a combo 4k page */ #define _PAGE_4K_PFN 0x20000000 /* PFN is for a single 4k page */ +/* For 64K page, we don't have a separate _PAGE_HASHPTE bit. Instead, + * we set that to be the whole sub-bits mask. The C code will only + * test this, so a multi-bit mask will work. For combo pages, this + * is equivalent as effectively, the old _PAGE_HASHPTE was an OR of + * all the sub bits. For real 64k pages, we now have the assembly set + * _PAGE_HPTE_SUB0 in addition to setting the HIDX bits which overlap + * that mask. This is fine as long as the HIDX bits are never set on + * a PTE that isn't hashed, which is the case today. + * + * A little nit is for the huge page C code, which does the hashing + * in C, we need to provide which bit to use. + */ +#define _PAGE_HASHPTE _PAGE_HPTE_SUB + /* Note the full page bits must be in the same location as for normal * 4k pages as the same asssembly will be used to insert 64K pages * wether the kernel has CONFIG_PPC_64K_PAGES or not @@ -83,8 +97,7 @@ static inline struct subpage_prot_table *pgd_subpage_prot(pgd_t *pgd) #define _PAGE_F_GIX 0x00007000 /* full page: hidx bits */ /* PTE flags to conserve for HPTE identification */ -#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_HPTE_SUB |\ - _PAGE_COMBO) +#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_COMBO) /* Shift to put page number into pte. * diff --git a/include/asm-powerpc/pgtable-ppc64.h b/include/asm-powerpc/pgtable-ppc64.h index cc6a43ba41d0..2e48be841cc9 100644 --- a/include/asm-powerpc/pgtable-ppc64.h +++ b/include/asm-powerpc/pgtable-ppc64.h @@ -91,7 +91,6 @@ #define _PAGE_DIRTY 0x0080 /* C: page changed */ #define _PAGE_ACCESSED 0x0100 /* R: page referenced */ #define _PAGE_RW 0x0200 /* software: user write access allowed */ -#define _PAGE_HASHPTE 0x0400 /* software: pte has an associated HPTE */ #define _PAGE_BUSY 0x0800 /* software: PTE & hash are busy */ #define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_COHERENT)