mirror of https://gitee.com/openkylin/linux.git
228 lines
7.4 KiB
C
228 lines
7.4 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle
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* Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
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*/
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#ifndef _ASM_PGTABLE_64_H
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#define _ASM_PGTABLE_64_H
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#include <linux/config.h>
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#include <linux/linkage.h>
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#include <asm/addrspace.h>
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#include <asm/page.h>
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#include <asm/cachectl.h>
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/*
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* Each address space has 2 4K pages as its page directory, giving 1024
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* (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
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* pair of 4K pages, giving 1024 (== PTRS_PER_PMD) 8 byte pointers to
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* page tables. Each page table is a single 4K page, giving 512 (==
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* PTRS_PER_PTE) 8 byte ptes. Each pgde is initialized to point to
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* invalid_pmd_table, each pmde is initialized to point to
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* invalid_pte_table, each pte is initialized to 0. When memory is low,
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* and a pmd table or a page table allocation fails, empty_bad_pmd_table
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* and empty_bad_page_table is returned back to higher layer code, so
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* that the failure is recognized later on. Linux does not seem to
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* handle these failures very well though. The empty_bad_page_table has
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* invalid pte entries in it, to force page faults.
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*
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* Kernel mappings: kernel mappings are held in the swapper_pg_table.
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* The layout is identical to userspace except it's indexed with the
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* fault address - VMALLOC_START.
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*/
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/* PMD_SHIFT determines the size of the area a second-level page table can map */
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#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT - 3))
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#define PMD_SIZE (1UL << PMD_SHIFT)
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#define PMD_MASK (~(PMD_SIZE-1))
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/* PGDIR_SHIFT determines what a third-level page table entry can map */
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#define PGDIR_SHIFT (PMD_SHIFT + (PAGE_SHIFT + 1 - 3))
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#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
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#define PGDIR_MASK (~(PGDIR_SIZE-1))
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/*
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* For 4kB page size we use a 3 level page tree and a 8kB pmd and pgds which
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* permits us mapping 40 bits of virtual address space.
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*
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* We used to implement 41 bits by having an order 1 pmd level but that seemed
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* rather pointless.
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*
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* For 8kB page size we use a 3 level page tree which permits a total of
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* 8TB of address space. Alternatively a 33-bit / 8GB organization using
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* two levels would be easy to implement.
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*
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* For 16kB page size we use a 2 level page tree which permits a total of
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* 36 bits of virtual address space. We could add a third leve. but it seems
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* like at the moment there's no need for this.
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*
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* For 64kB page size we use a 2 level page table tree for a total of 42 bits
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* of virtual address space.
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*/
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#ifdef CONFIG_PAGE_SIZE_4KB
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#define PGD_ORDER 1
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#define PMD_ORDER 0
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#define PTE_ORDER 0
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#endif
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#ifdef CONFIG_PAGE_SIZE_8KB
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#define PGD_ORDER 0
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#define PMD_ORDER 0
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#define PTE_ORDER 0
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#endif
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#ifdef CONFIG_PAGE_SIZE_16KB
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#define PGD_ORDER 0
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#define PMD_ORDER 0
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#define PTE_ORDER 0
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#endif
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#ifdef CONFIG_PAGE_SIZE_64KB
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#define PGD_ORDER 0
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#define PMD_ORDER 0
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#define PTE_ORDER 0
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#endif
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#define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
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#define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
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#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
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#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
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#define FIRST_USER_ADDRESS 0
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#define VMALLOC_START XKSEG
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#define VMALLOC_END \
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(VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
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#define pte_ERROR(e) \
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printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
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#define pmd_ERROR(e) \
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printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
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#define pgd_ERROR(e) \
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printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
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extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];
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extern pte_t empty_bad_page_table[PAGE_SIZE/sizeof(pte_t)];
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extern pmd_t invalid_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
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extern pmd_t empty_bad_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
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/*
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* Empty pmd entries point to the invalid_pte_table.
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*/
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static inline int pmd_none(pmd_t pmd)
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{
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return pmd_val(pmd) == (unsigned long) invalid_pte_table;
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}
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#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
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static inline int pmd_present(pmd_t pmd)
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{
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return pmd_val(pmd) != (unsigned long) invalid_pte_table;
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}
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static inline void pmd_clear(pmd_t *pmdp)
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{
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pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
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}
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/*
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* Empty pgd entries point to the invalid_pmd_table.
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*/
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static inline int pgd_none(pgd_t pgd)
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{
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return pgd_val(pgd) == (unsigned long) invalid_pmd_table;
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}
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#define pgd_bad(pgd) (pgd_val(pgd) &~ PAGE_MASK)
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static inline int pgd_present(pgd_t pgd)
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{
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return pgd_val(pgd) != (unsigned long) invalid_pmd_table;
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}
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static inline void pgd_clear(pgd_t *pgdp)
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{
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pgd_val(*pgdp) = ((unsigned long) invalid_pmd_table);
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}
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#define pte_page(x) pfn_to_page((unsigned long)((pte_val(x) >> PAGE_SHIFT)))
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#ifdef CONFIG_CPU_VR41XX
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#define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
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#define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
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#else
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#define pte_pfn(x) ((unsigned long)((x).pte >> PAGE_SHIFT))
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#define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
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#endif
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#define __pgd_offset(address) pgd_index(address)
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#define page_pte(page) page_pte_prot(page, __pgprot(0))
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/* to find an entry in a kernel page-table-directory */
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#define pgd_offset_k(address) pgd_offset(&init_mm, 0)
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#define pgd_index(address) ((address) >> PGDIR_SHIFT)
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/* to find an entry in a page-table-directory */
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#define pgd_offset(mm,addr) ((mm)->pgd + pgd_index(addr))
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static inline unsigned long pgd_page(pgd_t pgd)
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{
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return pgd_val(pgd);
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}
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/* Find an entry in the second-level page table.. */
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static inline pmd_t *pmd_offset(pgd_t * dir, unsigned long address)
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{
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return (pmd_t *) pgd_page(*dir) +
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((address >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
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}
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/* Find an entry in the third-level page table.. */
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#define __pte_offset(address) \
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(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
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#define pte_offset(dir, address) \
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((pte_t *) (pmd_page_kernel(*dir)) + __pte_offset(address))
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#define pte_offset_kernel(dir, address) \
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((pte_t *) pmd_page_kernel(*(dir)) + __pte_offset(address))
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#define pte_offset_map(dir, address) \
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((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
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#define pte_offset_map_nested(dir, address) \
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((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
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#define pte_unmap(pte) ((void)(pte))
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#define pte_unmap_nested(pte) ((void)(pte))
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/*
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* Initialize a new pgd / pmd table with invalid pointers.
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*/
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extern void pgd_init(unsigned long page);
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extern void pmd_init(unsigned long page, unsigned long pagetable);
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/*
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* Non-present pages: high 24 bits are offset, next 8 bits type,
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* low 32 bits zero.
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*/
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static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
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{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
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#define __swp_type(x) (((x).val >> 32) & 0xff)
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#define __swp_offset(x) ((x).val >> 40)
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#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
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#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
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#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
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/*
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* Bits 0, 1, 2, 7 and 8 are taken, split up the 32 bits of offset
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* into this range:
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*/
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#define PTE_FILE_MAX_BITS 32
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#define pte_to_pgoff(_pte) \
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((((_pte).pte >> 3) & 0x1f ) + (((_pte).pte >> 9) << 6 ))
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#define pgoff_to_pte(off) \
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((pte_t) { (((off) & 0x1f) << 3) + (((off) >> 6) << 9) + _PAGE_FILE })
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#endif /* _ASM_PGTABLE_64_H */
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