FreeBSD/Linux Kernel Cross Reference
sys/include/asm-alpha/pgtable.h

     #ifndef _ALPHA_PGTABLE_H
     #define _ALPHA_PGTABLE_H
     
     /*
      * This file contains the functions and defines necessary to modify and use
      * the Alpha page table tree.
      *
      * This hopefully works with any standard Alpha page-size, as defined
      * in <asm/page.h> (currently 8192).
     */
    #include <linux/config.h>
    #include <linux/mmzone.h>
    
    #include <asm/page.h>
    #include <asm/processor.h>      /* For TASK_SIZE */
    #include <asm/machvec.h>
    
    /* Certain architectures need to do special things when PTEs
     * within a page table are directly modified.  Thus, the following
     * hook is made available.
     */
    #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
    
    /* PMD_SHIFT determines the size of the area a second-level page table can map */
    #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-3))
    #define PMD_SIZE        (1UL << PMD_SHIFT)
    #define PMD_MASK        (~(PMD_SIZE-1))
    
    /* PGDIR_SHIFT determines what a third-level page table entry can map */
    #define PGDIR_SHIFT     (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
    #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
    #define PGDIR_MASK      (~(PGDIR_SIZE-1))
    
    /*
     * Entries per page directory level:  the Alpha is three-level, with
     * all levels having a one-page page table.
     */
    #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-3))
    #define PTRS_PER_PMD    (1UL << (PAGE_SHIFT-3))
    #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-3))
    #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
    #define FIRST_USER_PGD_NR       0
    
    /* Number of pointers that fit on a page:  this will go away. */
    #define PTRS_PER_PAGE   (1UL << (PAGE_SHIFT-3))
    
    #ifdef CONFIG_ALPHA_LARGE_VMALLOC
    #define VMALLOC_START           0xfffffe0000000000
    #else
    #define VMALLOC_START           (-2*PGDIR_SIZE)
    #endif
    #define VMALLOC_VMADDR(x)       ((unsigned long)(x))
    #define VMALLOC_END             (-PGDIR_SIZE)
    
    /*
     * OSF/1 PAL-code-imposed page table bits
     */
    #define _PAGE_VALID     0x0001
    #define _PAGE_FOR       0x0002  /* used for page protection (fault on read) */
    #define _PAGE_FOW       0x0004  /* used for page protection (fault on write) */
    #define _PAGE_FOE       0x0008  /* used for page protection (fault on exec) */
    #define _PAGE_ASM       0x0010
    #define _PAGE_KRE       0x0100  /* xxx - see below on the "accessed" bit */
    #define _PAGE_URE       0x0200  /* xxx */
    #define _PAGE_KWE       0x1000  /* used to do the dirty bit in software */
    #define _PAGE_UWE       0x2000  /* used to do the dirty bit in software */
    
    /* .. and these are ours ... */
    #define _PAGE_DIRTY     0x20000
    #define _PAGE_ACCESSED  0x40000
    
    /*
     * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
     * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
     * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
     * the KRE/URE bits to watch for it. That way we don't need to overload the
     * KWE/UWE bits with both handling dirty and accessed.
     *
     * Note that the kernel uses the accessed bit just to check whether to page
     * out a page or not, so it doesn't have to be exact anyway.
     */
    
    #define __DIRTY_BITS    (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
    #define __ACCESS_BITS   (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
    
    #define _PFN_MASK       0xFFFFFFFF00000000
    
    #define _PAGE_TABLE     (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
    #define _PAGE_CHG_MASK  (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
    
    /*
     * All the normal masks have the "page accessed" bits on, as any time they are used,
     * the page is accessed. They are cleared only by the page-out routines
     */
    #define PAGE_NONE       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
    #define PAGE_SHARED     __pgprot(_PAGE_VALID | __ACCESS_BITS)
    #define PAGE_COPY       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
    #define PAGE_READONLY   __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
    #define PAGE_KERNEL     __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
   
   #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
   
   #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
   #define _PAGE_S(x) _PAGE_NORMAL(x)
   
   /*
    * The hardware can handle write-only mappings, but as the Alpha
    * architecture does byte-wide writes with a read-modify-write
    * sequence, it's not practical to have write-without-read privs.
    * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
    * arch/alpha/mm/fault.c)
    */
           /* xwr */
   #define __P000  _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
   #define __P001  _PAGE_P(_PAGE_FOE | _PAGE_FOW)
   #define __P010  _PAGE_P(_PAGE_FOE)
   #define __P011  _PAGE_P(_PAGE_FOE)
   #define __P100  _PAGE_P(_PAGE_FOW | _PAGE_FOR)
   #define __P101  _PAGE_P(_PAGE_FOW)
   #define __P110  _PAGE_P(0)
   #define __P111  _PAGE_P(0)
   
   #define __S000  _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
   #define __S001  _PAGE_S(_PAGE_FOE | _PAGE_FOW)
   #define __S010  _PAGE_S(_PAGE_FOE)
   #define __S011  _PAGE_S(_PAGE_FOE)
   #define __S100  _PAGE_S(_PAGE_FOW | _PAGE_FOR)
   #define __S101  _PAGE_S(_PAGE_FOW)
   #define __S110  _PAGE_S(0)
   #define __S111  _PAGE_S(0)
   
   /*
    * BAD_PAGETABLE is used when we need a bogus page-table, while
    * BAD_PAGE is used for a bogus page.
    *
    * ZERO_PAGE is a global shared page that is always zero:  used
    * for zero-mapped memory areas etc..
    */
   extern pte_t __bad_page(void);
   extern pmd_t * __bad_pagetable(void);
   
   extern unsigned long __zero_page(void);
   
   #define BAD_PAGETABLE   __bad_pagetable()
   #define BAD_PAGE        __bad_page()
   #define ZERO_PAGE(vaddr)        (virt_to_page(ZERO_PGE))
   
   /* number of bits that fit into a memory pointer */
   #define BITS_PER_PTR                    (8*sizeof(unsigned long))
   
   /* to align the pointer to a pointer address */
   #define PTR_MASK                        (~(sizeof(void*)-1))
   
   /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
   #define SIZEOF_PTR_LOG2                 3
   
   /* to find an entry in a page-table */
   #define PAGE_PTR(address)               \
     ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
   
   /*
    * On certain platforms whose physical address space can overlap KSEG,
    * namely EV6 and above, we must re-twiddle the physaddr to restore the
    * correct high-order bits.
    *
    * This is extremely confusing until you realize that this is actually
    * just working around a userspace bug.  The X server was intending to
    * provide the physical address but instead provided the KSEG address.
    * Or tried to, except it's not representable.
    * 
    * On Tsunami there's nothing meaningful at 0x40000000000, so this is
    * a safe thing to do.  Come the first core logic that does put something
    * in this area -- memory or whathaveyou -- then this hack will have
    * to go away.  So be prepared!
    */
   
   #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
   #error "EV6-only feature in a generic kernel"
   #endif
   #if defined(CONFIG_ALPHA_GENERIC) || \
       (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
   #define PHYS_TWIDDLE(phys) \
     ((((phys) & 0xc0000000000UL) == 0x40000000000UL) \
     ? ((phys) ^= 0xc0000000000UL) : (phys))
   #else
   #define PHYS_TWIDDLE(phys) (phys)
   #endif
   
   /*
    * Conversion functions:  convert a page and protection to a page entry,
    * and a page entry and page directory to the page they refer to.
    */
   #ifndef CONFIG_DISCONTIGMEM
   #define PAGE_TO_PA(page)        ((page - mem_map) << PAGE_SHIFT)
   #else
   #define PAGE_TO_PA(page) \
                   ((((page)-page_zone(page)->zone_mem_map) << PAGE_SHIFT) \
                   + page_zone(page)->zone_start_paddr)
   #endif
   
   #ifndef CONFIG_DISCONTIGMEM
   #define mk_pte(page, pgprot)                                            \
   ({                                                                      \
           pte_t pte;                                                      \
                                                                           \
           pte_val(pte) = ((unsigned long)(page - mem_map) << 32) |        \
                          pgprot_val(pgprot);                              \
           pte;                                                            \
   })
   #else
   #define mk_pte(page, pgprot)                                                    \
   ({                                                                              \
           pte_t pte;                                                              \
           unsigned long pfn;                                                      \
                                                                                   \
           pfn = ((unsigned long)((page)-page_zone(page)->zone_mem_map)) << 32;    \
           pfn += page_zone(page)->zone_start_paddr << (32-PAGE_SHIFT);            \
           pte_val(pte) = pfn | pgprot_val(pgprot);                                \
                                                                                   \
           pte;                                                                    \
   })
   #endif
   
   extern inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
   { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpage) << (32-PAGE_SHIFT)) | pgprot_val(pgprot); return pte; }
   
   extern 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 inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
   { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
   
   extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
   { pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
   
   #ifndef CONFIG_DISCONTIGMEM
   #define pte_page(x)     (mem_map+(unsigned long)((pte_val(x) >> 32)))
   #else
   #define pte_page(x)                                                     \
   ({                                                                      \
           unsigned long kvirt;                                            \
           struct page * __xx;                                             \
                                                                           \
           kvirt = (unsigned long)__va(pte_val(x) >> (32-PAGE_SHIFT));     \
           __xx = virt_to_page(kvirt);                                     \
                                                                           \
           __xx;                                                           \
   })
   #endif
   
   extern inline unsigned long pmd_page(pmd_t pmd)
   { return PAGE_OFFSET + ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
   
   extern inline unsigned long pgd_page(pgd_t pgd)
   { return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
   
   extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
   extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_VALID; }
   extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
   
   extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
   extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
   extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_VALID; }
   extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
   
   extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
   extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
   extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_VALID; }
   extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
   
   /*
    * The following only work if pte_present() is true.
    * Undefined behaviour if not..
    */
   extern inline int pte_read(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOR); }
   extern inline int pte_write(pte_t pte)          { return !(pte_val(pte) & _PAGE_FOW); }
   extern inline int pte_exec(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOE); }
   extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
   extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
   
   extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
   extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOR; return pte; }
   extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOE; return pte; }
   extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
   extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
   extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
   extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOR; return pte; }
   extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOE; return pte; }
   extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
   extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
   
   #define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
   
   /* to find an entry in a kernel page-table-directory */
   #define pgd_offset_k(address) pgd_offset(&init_mm, address)
   
   /* to find an entry in a page-table-directory. */
   #define pgd_index(address)      ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
   #define __pgd_offset(address)   pgd_index(address)
   #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
   
   /* Find an entry in the second-level page table.. */
   extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
   {
           return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
   }
   
   /* Find an entry in the third-level page table.. */
   extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
   {
           return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
   }
   
   extern pgd_t swapper_pg_dir[1024];
   
   /*
    * The Alpha doesn't have any external MMU info:  the kernel page
    * tables contain all the necessary information.
    */
   extern inline void update_mmu_cache(struct vm_area_struct * vma,
           unsigned long address, pte_t pte)
   {
   }
   
   /*
    * Non-present pages:  high 24 bits are offset, next 8 bits type,
    * low 32 bits zero.
    */
   extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
   { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
   
   #define SWP_TYPE(x)                     (((x).val >> 32) & 0xff)
   #define SWP_OFFSET(x)                   ((x).val >> 40)
   #define SWP_ENTRY(type, offset)         ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
   #define pte_to_swp_entry(pte)           ((swp_entry_t) { pte_val(pte) })
   #define swp_entry_to_pte(x)             ((pte_t) { (x).val })
   
   /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
   #define PageSkip(page)          (0)
   
   #ifndef CONFIG_DISCONTIGMEM
   #define kern_addr_valid(addr)   (1)
   #endif
   
   #define io_remap_page_range(start, busaddr, size, prot) \
       remap_page_range(start, virt_to_phys(__ioremap(busaddr, size)), size, prot)
   
   #define pte_ERROR(e) \
           printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
   #define pmd_ERROR(e) \
           printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
   #define pgd_ERROR(e) \
           printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
   
   extern void paging_init(void);
   
   #include <asm-generic/pgtable.h>
   
   /*
    * No page table caches to initialise
    */
   #define pgtable_cache_init()    do { } while (0)
   
   /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
   #define HAVE_ARCH_UNMAPPED_AREA
   
   #endif /* _ALPHA_PGTABLE_H */

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