/* * 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 <linux/config.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_kernel(pmd) ((pte_t *)(pmd_val((pmd)) & ~_PMD_PRESENT)) #define pte_offset_kernel(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr)) #define pte_offset_map(dir,addr) (pmd_page_kernel(*(dir)) + __pte_index(addr)) #define pte_offset_map_nested(dir,addr) (pmd_page_kernel(*(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_read(pte) (!(pte_val(pte) & _PAGE_NOT_USER)) #define pte_write(pte) (!(pte_val(pte) & _PAGE_READONLY)) #define pte_exec(pte) (!(pte_val(pte) & _PAGE_NOT_USER)) #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(exprotect, |= _PAGE_NOT_USER); PTE_BIT_FUNC(mkexec, &= ~_PAGE_NOT_USER); 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) #define MK_IOSPACE_PFN(space, pfn) (pfn) #define GET_IOSPACE(pfn) 0 #define GET_PFN(pfn) (pfn) #endif /* !__ASSEMBLY__ */ #endif /* _ASMARM_PGTABLE_H */