From 41743a4e34f0777f51c1cf0675b91508ba143050 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 11 Jun 2008 15:37:10 +1000 Subject: 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 --- include/asm-powerpc/pgtable-64k.h | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'include/asm-powerpc/pgtable-64k.h') diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h index 1cbd6b377ee..c5007712473 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. * -- cgit v1.2.3-70-g09d2