From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <41C94427.9020601@yahoo.com.au> Date: Wed, 22 Dec 2004 20:53:43 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: [PATCH 2/11] generic 3-level nopmd folding header References: <41C94361.6070909@yahoo.com.au> <41C943F0.4090006@yahoo.com.au> In-Reply-To: <41C943F0.4090006@yahoo.com.au> Content-Type: multipart/mixed; boundary="------------020306020701020102000104" Sender: owner-linux-mm@kvack.org Return-Path: To: Linus Torvalds Cc: Andrew Morton , Andi Kleen , Hugh Dickins , Linux Memory Management List-ID: This is a multi-part message in MIME format. --------------020306020701020102000104 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 2/11 --------------020306020701020102000104 Content-Type: text/plain; name="3level-compat.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="3level-compat.patch" Generic headers to fold the 3-level pagetable into 2 levels. Signed-off-by: Nick Piggin --- linux-2.6-npiggin/include/asm-generic/pgtable-nopmd.h | 59 ++++++++++++++++++ 1 files changed, 59 insertions(+) diff -puN /dev/null include/asm-generic/pgtable-nopmd.h --- /dev/null 2004-09-06 19:38:39.000000000 +1000 +++ linux-2.6-npiggin/include/asm-generic/pgtable-nopmd.h 2004-12-22 20:35:57.000000000 +1100 @@ -0,0 +1,59 @@ +#ifndef _PGTABLE_NOPMD_H +#define _PGTABLE_NOPMD_H + +#ifndef __ASSEMBLY__ + +/* + * Having the pmd type consist of a pgd gets the size right, and allows + * us to conceptually access the pgd entry that this pmd is folded into + * without casting. + */ +typedef struct { pgd_t pgd; } pmd_t; + +#define PMD_SHIFT PGDIR_SHIFT +#define PTRS_PER_PMD 1 +#define PMD_SIZE (1UL << PMD_SHIFT) +#define PMD_MASK (~(PMD_SIZE-1)) + +/* + * The "pgd_xxx()" functions here are trivial for a folded two-level + * setup: the pmd is never bad, and a pmd always exists (as it's folded + * into the pgd entry) + */ +static inline int pgd_none(pgd_t pgd) { return 0; } +static inline int pgd_bad(pgd_t pgd) { return 0; } +static inline int pgd_present(pgd_t pgd) { return 1; } +static inline void pgd_clear(pgd_t *pgd) { } +#define pmd_ERROR(pmd) (pgd_ERROR((pmd).pgd)) + +#define pgd_populate(mm, pmd, pte) do { } while (0) +#define pgd_populate_kernel(mm, pmd, pte) do { } while (0) + +/* + * (pmds are folded into pgds so this doesn't get actually called, + * but the define is needed for a generic inline function.) + */ +#define set_pgd(pgdptr, pgdval) set_pmd((pmd_t *)(pgdptr), (pmd_t) { pgdval }) + +static inline pmd_t * pmd_offset(pgd_t * pgd, unsigned long address) +{ + return (pmd_t *)pgd; +} + +#define pmd_val(x) (pgd_val((x).pgd)) +#define __pmd(x) ((pmd_t) { __pgd(x) } ) + +#define pgd_page(pgd) (pmd_page((pmd_t){ pgd })) +#define pgd_page_kernel(pgd) (pmd_page_kernel((pmd_t){ pgd })) + +/* + * allocating and freeing a pmd is trivial: the 1-entry pmd is + * inside the pgd, so has no extra memory associated with it. + */ +#define pmd_alloc_one(mm, address) NULL +#define pmd_free(x) do { } while (0) +#define __pmd_free_tlb(tlb, x) do { } while (0) + +#endif /* __ASSEMBLY__ */ + +#endif /* _PGTABLE_NOPMD_H */ _ --------------020306020701020102000104-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org