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linux/include/asm-arm26/pgtable.h

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/*
* linux/include/asm-arm26/pgtable.h
*
* Copyright (C) 2000-2002 Russell King
* Copyright (C) 2003 Ian Molton
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASMARM_PGTABLE_H
#define _ASMARM_PGTABLE_H
#include <asm-generic/4level-fixup.h>
#include <asm/memory.h>
/*
* The table below defines the page protection levels that we insert into our
* Linux page table version. These get translated into the best that the
* architecture can perform. Note that on most ARM hardware:
* 1) We cannot do execute protection
* 2) If we could do execute protection, then read is implied
* 3) write implies read permissions
*/
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY
#define __P010 PAGE_COPY
#define __P011 PAGE_COPY
#define __P100 PAGE_READONLY
#define __P101 PAGE_READONLY
#define __P110 PAGE_COPY
#define __P111 PAGE_COPY
#define __S000 PAGE_NONE
#define __S001 PAGE_READONLY
#define __S010 PAGE_SHARED
#define __S011 PAGE_SHARED
#define __S100 PAGE_READONLY
#define __S101 PAGE_READONLY
#define __S110 PAGE_SHARED
#define __S111 PAGE_SHARED
/*
* PMD_SHIFT determines the size of the area a second-level page table can map
* PGDIR_SHIFT determines what a third-level page table entry can map
*/
#define PGD_SHIFT 25
#define PMD_SHIFT 20
#define PGD_SIZE (1UL << PGD_SHIFT)
#define PGD_MASK (~(PGD_SIZE-1))
#define PMD_SIZE (1UL << PMD_SHIFT)
#define PMD_MASK (~(PMD_SIZE-1))
/* The kernel likes to use these names for the above (ick) */
#define PGDIR_SIZE PGD_SIZE
#define PGDIR_MASK PGD_MASK
#define PTRS_PER_PGD 32
#define PTRS_PER_PMD 1
#define PTRS_PER_PTE 32
/*
* This is the lowest virtual address we can permit any user space
* mapping to be mapped at. This is particularly important for
* non-high vector CPUs.
*/
#define FIRST_USER_ADDRESS PAGE_SIZE
#define FIRST_USER_PGD_NR 1
#define USER_PTRS_PER_PGD ((TASK_SIZE/PGD_SIZE) - FIRST_USER_PGD_NR)
// FIXME - WTF?
#define LIBRARY_TEXT_START 0x0c000000
#ifndef __ASSEMBLY__
extern void __pte_error(const char *file, int line, unsigned long val);
extern void __pmd_error(const char *file, int line, unsigned long val);
extern void __pgd_error(const char *file, int line, unsigned long val);
#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte))
#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
extern struct page *empty_zero_page;
#define ZERO_PAGE(vaddr) (empty_zero_page)
#define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
#define pte_page(pte) (pfn_to_page(pte_pfn(pte)))
#define pfn_pte(pfn,prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
#define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
#define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot)
/*
* Terminology: PGD = Page Directory, PMD = Page Middle Directory,
* PTE = Page Table Entry
*
* on arm26 we have no 2nd level page table. we simulate this by removing the
* PMD.
*
* pgd_none is 0 to prevernt pmd_alloc() calling __pmd_alloc(). This causes it
* to return pmd_offset(pgd,addr) which is a pointer to the pgd (IOW, a no-op).
*
* however, to work this way, whilst we are allocating 32 pgds, containing 32
* PTEs, the actual work is done on the PMDs, thus:
*
* instead of mm->pgd->pmd->pte
* we have mm->pgdpmd->pte
*
* IOW, think of PGD operations and PMD ones as being the same thing, just
* that PGD stuff deals with the mm_struct side of things, wheras PMD stuff
* deals with the pte side of things.
*
* additionally, we store some bits in the PGD and PTE pointers:
* PGDs:
* o The lowest (1) bit of the PGD is to determine if it is present or swap.
* o The 2nd bit of the PGD is unused and must be zero.
* o The top 6 bits of the PGD must be zero.
* PTEs:
* o The lower 5 bits of a pte are flags. bit 1 is the 'present' flag. The
* others determine the pages attributes.
*
* the pgd_val, pmd_val, and pte_val macros seem to be private to our code.
* They get the RAW value of the PGD/PMD/PTE entry, including our flags
* encoded into the pointers.
*
* The pgd_offset, pmd_offset, and pte_offset macros are used by the kernel,
* so they shouldnt have our flags attached.
*
* If you understood that, feel free to explain it to me...
*
*/
#define _PMD_PRESENT (0x01)
/* These definitions allow us to optimise out stuff like pmd_alloc() */
#define pgd_none(pgd) (0)
#define pgd_bad(pgd) (0)
#define pgd_present(pgd) (1)
#define pgd_clear(pgdp) do { } while (0)
/* Whilst these handle our actual 'page directory' (the agglomeration of pgd and pmd)
*/
#define pmd_none(pmd) (!pmd_val(pmd))
#define pmd_bad(pmd) ((pmd_val(pmd) & 0xfc000002))
#define pmd_present(pmd) (pmd_val(pmd) & _PMD_PRESENT)
#define set_pmd(pmd_ptr, pmd) ((*(pmd_ptr)) = (pmd))
#define pmd_clear(pmdp) set_pmd(pmdp, __pmd(0))
/* and these handle our pte tables */
#define pte_none(pte) (!pte_val(pte))
#define pte_present(pte) (pte_val(pte) & _PAGE_PRESENT)
#define set_pte(pte_ptr, pte) ((*(pte_ptr)) = (pte))
#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
#define pte_clear(mm,addr,ptep) set_pte_at((mm),(addr),(ptep), __pte(0))
/* macros to ease the getting of pointers to stuff... */
#define pgd_offset(mm, addr) ((pgd_t *)(mm)->pgd + __pgd_index(addr))
#define pmd_offset(pgd, addr) ((pmd_t *)(pgd))
#define pte_offset(pmd, addr) ((pte_t *)pmd_page(*(pmd)) + __pte_index(addr))
/* there is no __pmd_index as we dont use pmds */
#define __pgd_index(addr) ((addr) >> PGD_SHIFT)
#define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
/* Keep the kernel happy */
#define pgd_index(addr) __pgd_index(addr)
#define pgd_offset_k(addr) (pgd_offset(&init_mm, addr))
/*
* The vmalloc() routines leaves a hole of 4kB between each vmalloced
* area for the same reason. ;) FIXME: surely 1 page not 4k ?
*/
#define VMALLOC_START 0x01a00000
#define VMALLOC_END 0x01c00000
/* Is pmd_page supposed to return a pointer to a page in some arches? ours seems to
* return a pointer to memory (no special alignment)
*/
#define pmd_page(pmd) ((struct page *)(pmd_val((pmd)) & ~_PMD_PRESENT))
#define pmd_page_vaddr(pmd) ((pte_t *)(pmd_val((pmd)) & ~_PMD_PRESENT))
#define pte_offset_kernel(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr))
#define pte_offset_map(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr))
#define pte_offset_map_nested(dir,addr) (pmd_page_vaddr(*(dir)) + __pte_index(addr))
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
#define _PAGE_PRESENT 0x01
#define _PAGE_READONLY 0x02
#define _PAGE_NOT_USER 0x04
#define _PAGE_OLD 0x08
#define _PAGE_CLEAN 0x10
// an old page has never been read.
// a clean page has never been written.
/* -- present -- -- !dirty -- --- !write --- ---- !user --- */
#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY | _PAGE_NOT_USER)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_CLEAN )
#define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY )
#define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_CLEAN | _PAGE_READONLY )
#define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_NOT_USER)
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_OLD | _PAGE_CLEAN)
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
#define pte_write(pte) (!(pte_val(pte) & _PAGE_READONLY))
#define pte_dirty(pte) (!(pte_val(pte) & _PAGE_CLEAN))
#define pte_young(pte) (!(pte_val(pte) & _PAGE_OLD))
//ONLY when !pte_present() I think. nicked from arm32 (FIXME!)
#define pte_file(pte) (!(pte_val(pte) & _PAGE_OLD))
#define PTE_BIT_FUNC(fn,op) \
static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
PTE_BIT_FUNC(wrprotect, |= _PAGE_READONLY);
PTE_BIT_FUNC(mkwrite, &= ~_PAGE_READONLY);
PTE_BIT_FUNC(mkclean, |= _PAGE_CLEAN);
PTE_BIT_FUNC(mkdirty, &= ~_PAGE_CLEAN);
PTE_BIT_FUNC(mkold, |= _PAGE_OLD);
PTE_BIT_FUNC(mkyoung, &= ~_PAGE_OLD);
/*
* We don't store cache state bits in the page table here. FIXME - or do we?
*/
#define pgprot_noncached(prot) (prot)
#define pgprot_writecombine(prot) (prot) //FIXME - is a no-op?
extern void pgtable_cache_init(void);
//FIXME - nicked from arm32 and brutally hacked. probably wrong.
#define pte_to_pgoff(x) (pte_val(x) >> 2)
#define pgoff_to_pte(x) __pte(((x) << 2) & ~_PAGE_OLD)
//FIXME - next line borrowed from arm32. is it right?
#define PTE_FILE_MAX_BITS 30
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
return pte;
}
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
/* Encode and decode a swap entry.
*
* We support up to 32GB of swap on 4k machines
*/
#define __swp_type(x) (((x).val >> 2) & 0x7f)
#define __swp_offset(x) ((x).val >> 9)
#define __swp_entry(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
/* FIXME: this is not correct */
#define kern_addr_valid(addr) (1)
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*/
static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
{
pte_t pte;
pte_val(pte) = physpage | pgprot_val(pgprot);
return pte;
}
#include <asm-generic/pgtable.h>
/*
* remap a physical page `pfn' of size `size' with page protection `prot'
* into virtual address `from'
*/
#define io_remap_pfn_range(vma,from,pfn,size,prot) \
remap_pfn_range(vma, from, pfn, size, prot)
#endif /* !__ASSEMBLY__ */
#endif /* _ASMARM_PGTABLE_H */
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