LXR linux-old/include/asm-alpha/pgtable.h

   1#ifndef _ALPHA_PGTABLE_H
   2#define _ALPHA_PGTABLE_H
   3
   4/*
   5 * This file contains the functions and defines necessary to modify and use
   6 * the Alpha page table tree.
   7 *
   8 * This hopefully works with any standard Alpha page-size, as defined
   9 * in <asm/page.h> (currently 8192).
  10 */
  11#include <linux/config.h>
  12#include <linux/mmzone.h>
  13
  14#include <asm/page.h>
  15#include <asm/processor.h>      /* For TASK_SIZE */
  16#include <asm/machvec.h>
  17
  18/* Certain architectures need to do special things when PTEs
  19 * within a page table are directly modified.  Thus, the following
  20 * hook is made available.
  21 */
  22#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  23
  24/* PMD_SHIFT determines the size of the area a second-level page table can map */
  25#define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-3))
  26#define PMD_SIZE        (1UL << PMD_SHIFT)
  27#define PMD_MASK        (~(PMD_SIZE-1))
  28
  29/* PGDIR_SHIFT determines what a third-level page table entry can map */
  30#define PGDIR_SHIFT     (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
  31#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  32#define PGDIR_MASK      (~(PGDIR_SIZE-1))
  33
  34/*
  35 * Entries per page directory level:  the Alpha is three-level, with
  36 * all levels having a one-page page table.
  37 */
  38#define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-3))
  39#define PTRS_PER_PMD    (1UL << (PAGE_SHIFT-3))
  40#define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-3))
  41#define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  42#define FIRST_USER_PGD_NR       0
  43
  44/* Number of pointers that fit on a page:  this will go away. */
  45#define PTRS_PER_PAGE   (1UL << (PAGE_SHIFT-3))
  46
  47#ifdef CONFIG_ALPHA_LARGE_VMALLOC
  48#define VMALLOC_START           0xfffffe0000000000
  49#else
  50#define VMALLOC_START           (-2*PGDIR_SIZE)
  51#endif
  52#define VMALLOC_VMADDR(x)       ((unsigned long)(x))
  53#define VMALLOC_END             (-PGDIR_SIZE)
  54
  55/*
  56 * OSF/1 PAL-code-imposed page table bits
  57 */
  58#define _PAGE_VALID     0x0001
  59#define _PAGE_FOR       0x0002  /* used for page protection (fault on read) */
  60#define _PAGE_FOW       0x0004  /* used for page protection (fault on write) */
  61#define _PAGE_FOE       0x0008  /* used for page protection (fault on exec) */
  62#define _PAGE_ASM       0x0010
  63#define _PAGE_KRE       0x0100  /* xxx - see below on the "accessed" bit */
  64#define _PAGE_URE       0x0200  /* xxx */
  65#define _PAGE_KWE       0x1000  /* used to do the dirty bit in software */
  66#define _PAGE_UWE       0x2000  /* used to do the dirty bit in software */
  67
  68/* .. and these are ours ... */
  69#define _PAGE_DIRTY     0x20000
  70#define _PAGE_ACCESSED  0x40000
  71
  72/*
  73 * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
  74 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
  75 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
  76 * the KRE/URE bits to watch for it. That way we don't need to overload the
  77 * KWE/UWE bits with both handling dirty and accessed.
  78 *
  79 * Note that the kernel uses the accessed bit just to check whether to page
  80 * out a page or not, so it doesn't have to be exact anyway.
  81 */
  82
  83#define __DIRTY_BITS    (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
  84#define __ACCESS_BITS   (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
  85
  86#define _PFN_MASK       0xFFFFFFFF00000000
  87
  88#define _PAGE_TABLE     (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
  89#define _PAGE_CHG_MASK  (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
  90
  91/*
  92 * All the normal masks have the "page accessed" bits on, as any time they are used,
  93 * the page is accessed. They are cleared only by the page-out routines
  94 */
  95#define PAGE_NONE       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
  96#define PAGE_SHARED     __pgprot(_PAGE_VALID | __ACCESS_BITS)
  97#define PAGE_COPY       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
  98#define PAGE_READONLY   __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
  99#define PAGE_KERNEL     __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
 100
 101#define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
 102
 103#define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
 104#define _PAGE_S(x) _PAGE_NORMAL(x)
 105
 106/*
 107 * The hardware can handle write-only mappings, but as the Alpha
 108 * architecture does byte-wide writes with a read-modify-write
 109 * sequence, it's not practical to have write-without-read privs.
 110 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
 111 * arch/alpha/mm/fault.c)
 112 */
 113        /* xwr */
 114#define __P000  _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 115#define __P001  _PAGE_P(_PAGE_FOE | _PAGE_FOW)
 116#define __P010  _PAGE_P(_PAGE_FOE)
 117#define __P011  _PAGE_P(_PAGE_FOE)
 118#define __P100  _PAGE_P(_PAGE_FOW | _PAGE_FOR)
 119#define __P101  _PAGE_P(_PAGE_FOW)
 120#define __P110  _PAGE_P(0)
 121#define __P111  _PAGE_P(0)
 122
 123#define __S000  _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 124#define __S001  _PAGE_S(_PAGE_FOE | _PAGE_FOW)
 125#define __S010  _PAGE_S(_PAGE_FOE)
 126#define __S011  _PAGE_S(_PAGE_FOE)
 127#define __S100  _PAGE_S(_PAGE_FOW | _PAGE_FOR)
 128#define __S101  _PAGE_S(_PAGE_FOW)
 129#define __S110  _PAGE_S(0)
 130#define __S111  _PAGE_S(0)
 131
 132/*
 133 * BAD_PAGETABLE is used when we need a bogus page-table, while
 134 * BAD_PAGE is used for a bogus page.
 135 *
 136 * ZERO_PAGE is a global shared page that is always zero:  used
 137 * for zero-mapped memory areas etc..
 138 */
 139extern pte_t __bad_page(void);
 140extern pmd_t * __bad_pagetable(void);
 141
 142extern unsigned long __zero_page(void);
 143
 144#define BAD_PAGETABLE   __bad_pagetable()
 145#define BAD_PAGE        __bad_page()
 146#define ZERO_PAGE(vaddr)        (virt_to_page(ZERO_PGE))
 147
 148/* number of bits that fit into a memory pointer */
 149#define BITS_PER_PTR                    (8*sizeof(unsigned long))
 150
 151/* to align the pointer to a pointer address */
 152#define PTR_MASK                        (~(sizeof(void*)-1))
 153
 154/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 155#define SIZEOF_PTR_LOG2                 3
 156
 157/* to find an entry in a page-table */
 158#define PAGE_PTR(address)               \
 159  ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 160
 161/*
 162 * On certain platforms whose physical address space can overlap KSEG,
 163 * namely EV6 and above, we must re-twiddle the physaddr to restore the
 164 * correct high-order bits.
 165 *
 166 * This is extremely confusing until you realize that this is actually
 167 * just working around a userspace bug.  The X server was intending to
 168 * provide the physical address but instead provided the KSEG address.
 169 * Or tried to, except it's not representable.
 170 * 
 171 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
 172 * a safe thing to do.  Come the first core logic that does put something
 173 * in this area -- memory or whathaveyou -- then this hack will have
 174 * to go away.  So be prepared!
 175 */
 176
 177#if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
 178#error "EV6-only feature in a generic kernel"
 179#endif
 180#if defined(CONFIG_ALPHA_GENERIC) || \
 181    (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
 182#define PHYS_TWIDDLE(phys) \
 183  ((((phys) & 0xc0000000000UL) == 0x40000000000UL) \
 184  ? ((phys) ^= 0xc0000000000UL) : (phys))
 185#else
 186#define PHYS_TWIDDLE(phys) (phys)
 187#endif
 188
 189/*
 190 * Conversion functions:  convert a page and protection to a page entry,
 191 * and a page entry and page directory to the page they refer to.
 192 */
 193#ifndef CONFIG_DISCONTIGMEM
 194#define PAGE_TO_PA(page)        ((page - mem_map) << PAGE_SHIFT)
 195#else
 196#define PAGE_TO_PA(page) \
 197                ((((page)-page_zone(page)->zone_mem_map) << PAGE_SHIFT) \
 198                + page_zone(page)->zone_start_paddr)
 199#endif
 200
 201#ifndef CONFIG_DISCONTIGMEM
 202#define mk_pte(page, pgprot)                                            \
 203({                                                                      \
 204        pte_t pte;                                                      \
 205                                                                        \
 206        pte_val(pte) = ((unsigned long)(page - mem_map) << 32) |        \
 207                       pgprot_val(pgprot);                              \
 208        pte;                                                            \
 209})
 210#else
 211#define mk_pte(page, pgprot)                                                    \
 212({                                                                              \
 213        pte_t pte;                                                              \
 214        unsigned long pfn;                                                      \
 215                                                                                \
 216        pfn = ((unsigned long)((page)-page_zone(page)->zone_mem_map)) << 32;    \
 217        pfn += page_zone(page)->zone_start_paddr << (32-PAGE_SHIFT);            \
 218        pte_val(pte) = pfn | pgprot_val(pgprot);                                \
 219                                                                                \
 220        pte;                                                                    \
 221})
 222#endif
 223
 224extern inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
 225{ pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpage) << (32-PAGE_SHIFT)) | pgprot_val(pgprot); return pte; }
 226
 227extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 228{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 229
 230extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 231{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 232
 233extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
 234{ pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 235
 236#ifndef CONFIG_DISCONTIGMEM
 237#define pte_page(x)     (mem_map+(unsigned long)((pte_val(x) >> 32)))
 238#else
 239#define pte_page(x)                                                     \
 240({                                                                      \
 241        unsigned long kvirt;                                            \
 242        struct page * __xx;                                             \
 243                                                                        \
 244        kvirt = (unsigned long)__va(pte_val(x) >> (32-PAGE_SHIFT));     \
 245        __xx = virt_to_page(kvirt);                                     \
 246                                                                        \
 247        __xx;                                                           \
 248})
 249#endif
 250
 251extern inline unsigned long pmd_page(pmd_t pmd)
 252{ return PAGE_OFFSET + ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 253
 254extern inline unsigned long pgd_page(pgd_t pgd)
 255{ return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 256
 257extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
 258extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_VALID; }
 259extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
 260
 261extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
 262extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
 263extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_VALID; }
 264extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
 265
 266extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
 267extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
 268extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_VALID; }
 269extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
 270
 271/*
 272 * The following only work if pte_present() is true.
 273 * Undefined behaviour if not..
 274 */
 275extern inline int pte_read(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOR); }
 276extern inline int pte_write(pte_t pte)          { return !(pte_val(pte) & _PAGE_FOW); }
 277extern inline int pte_exec(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOE); }
 278extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 279extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 280
 281extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
 282extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOR; return pte; }
 283extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOE; return pte; }
 284extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
 285extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
 286extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
 287extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOR; return pte; }
 288extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOE; return pte; }
 289extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
 290extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
 291
 292#define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 293
 294/* to find an entry in a kernel page-table-directory */
 295#define pgd_offset_k(address) pgd_offset(&init_mm, address)
 296
 297/* to find an entry in a page-table-directory. */
 298#define pgd_index(address)      ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 299#define __pgd_offset(address)   pgd_index(address)
 300#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 301
 302/* Find an entry in the second-level page table.. */
 303extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 304{
 305        return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
 306}
 307
 308/* Find an entry in the third-level page table.. */
 309extern inline pte_t * pte_offset(pmd_t * dir, unsigned long address)
 310{
 311        return (pte_t *) pmd_page(*dir) + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
 312}
 313
 314extern pgd_t swapper_pg_dir[1024];
 315
 316/*
 317 * The Alpha doesn't have any external MMU info:  the kernel page
 318 * tables contain all the necessary information.
 319 */
 320extern inline void update_mmu_cache(struct vm_area_struct * vma,
 321        unsigned long address, pte_t pte)
 322{
 323}
 324
 325/*
 326 * Non-present pages:  high 24 bits are offset, next 8 bits type,
 327 * low 32 bits zero.
 328 */
 329extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 330{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 331
 332#define SWP_TYPE(x)                     (((x).val >> 32) & 0xff)
 333#define SWP_OFFSET(x)                   ((x).val >> 40)
 334#define SWP_ENTRY(type, offset)         ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
 335#define pte_to_swp_entry(pte)           ((swp_entry_t) { pte_val(pte) })
 336#define swp_entry_to_pte(x)             ((pte_t) { (x).val })
 337
 338/* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
 339#define PageSkip(page)          (0)
 340
 341#ifndef CONFIG_DISCONTIGMEM
 342#define kern_addr_valid(addr)   (1)
 343#endif
 344
 345#define io_remap_page_range(start, busaddr, size, prot) \
 346    remap_page_range(start, virt_to_phys(__ioremap(busaddr, size)), size, prot)
 347
 348#define pte_ERROR(e) \
 349        printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 350#define pmd_ERROR(e) \
 351        printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 352#define pgd_ERROR(e) \
 353        printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 354
 355extern void paging_init(void);
 356
 357#include <asm-generic/pgtable.h>
 358
 359/*
 360 * No page table caches to initialise
 361 */
 362#define pgtable_cache_init()    do { } while (0)
 363
 364/* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
 365#define HAVE_ARCH_UNMAPPED_AREA
 366
 367#endif /* _ALPHA_PGTABLE_H */
 368