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

   1#ifndef _ALPHA_PGTABLE_H
   2#define _ALPHA_PGTABLE_H
   3
   4#include <asm-generic/4level-fixup.h>
   5
   6/*
   7 * This file contains the functions and defines necessary to modify and use
   8 * the Alpha page table tree.
   9 *
  10 * This hopefully works with any standard Alpha page-size, as defined
  11 * in <asm/page.h> (currently 8192).
  12 */
  13#include <linux/config.h>
  14#include <linux/mmzone.h>
  15
  16#include <asm/page.h>
  17#include <asm/processor.h>      /* For TASK_SIZE */
  18#include <asm/machvec.h>
  19
  20/* Certain architectures need to do special things when PTEs
  21 * within a page table are directly modified.  Thus, the following
  22 * hook is made available.
  23 */
  24#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  25
  26/* PMD_SHIFT determines the size of the area a second-level page table can map */
  27#define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT-3))
  28#define PMD_SIZE        (1UL << PMD_SHIFT)
  29#define PMD_MASK        (~(PMD_SIZE-1))
  30
  31/* PGDIR_SHIFT determines what a third-level page table entry can map */
  32#define PGDIR_SHIFT     (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
  33#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  34#define PGDIR_MASK      (~(PGDIR_SIZE-1))
  35
  36/*
  37 * Entries per page directory level:  the Alpha is three-level, with
  38 * all levels having a one-page page table.
  39 */
  40#define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-3))
  41#define PTRS_PER_PMD    (1UL << (PAGE_SHIFT-3))
  42#define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-3))
  43#define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  44#define FIRST_USER_PGD_NR       0
  45
  46/* Number of pointers that fit on a page:  this will go away. */
  47#define PTRS_PER_PAGE   (1UL << (PAGE_SHIFT-3))
  48
  49#ifdef CONFIG_ALPHA_LARGE_VMALLOC
  50#define VMALLOC_START           0xfffffe0000000000
  51#else
  52#define VMALLOC_START           (-2*PGDIR_SIZE)
  53#endif
  54#define VMALLOC_END             (-PGDIR_SIZE)
  55
  56/*
  57 * OSF/1 PAL-code-imposed page table bits
  58 */
  59#define _PAGE_VALID     0x0001
  60#define _PAGE_FOR       0x0002  /* used for page protection (fault on read) */
  61#define _PAGE_FOW       0x0004  /* used for page protection (fault on write) */
  62#define _PAGE_FOE       0x0008  /* used for page protection (fault on exec) */
  63#define _PAGE_ASM       0x0010
  64#define _PAGE_KRE       0x0100  /* xxx - see below on the "accessed" bit */
  65#define _PAGE_URE       0x0200  /* xxx */
  66#define _PAGE_KWE       0x1000  /* used to do the dirty bit in software */
  67#define _PAGE_UWE       0x2000  /* used to do the dirty bit in software */
  68
  69/* .. and these are ours ... */
  70#define _PAGE_DIRTY     0x20000
  71#define _PAGE_ACCESSED  0x40000
  72#define _PAGE_FILE      0x80000 /* set:pagecache, unset:swap */
  73
  74/*
  75 * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
  76 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
  77 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
  78 * the KRE/URE bits to watch for it. That way we don't need to overload the
  79 * KWE/UWE bits with both handling dirty and accessed.
  80 *
  81 * Note that the kernel uses the accessed bit just to check whether to page
  82 * out a page or not, so it doesn't have to be exact anyway.
  83 */
  84
  85#define __DIRTY_BITS    (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
  86#define __ACCESS_BITS   (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
  87
  88#define _PFN_MASK       0xFFFFFFFF00000000UL
  89
  90#define _PAGE_TABLE     (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
  91#define _PAGE_CHG_MASK  (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
  92
  93/*
  94 * All the normal masks have the "page accessed" bits on, as any time they are used,
  95 * the page is accessed. They are cleared only by the page-out routines
  96 */
  97#define PAGE_NONE       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
  98#define PAGE_SHARED     __pgprot(_PAGE_VALID | __ACCESS_BITS)
  99#define PAGE_COPY       __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
 100#define PAGE_READONLY   __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
 101#define PAGE_KERNEL     __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
 102
 103#define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
 104
 105#define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
 106#define _PAGE_S(x) _PAGE_NORMAL(x)
 107
 108/*
 109 * The hardware can handle write-only mappings, but as the Alpha
 110 * architecture does byte-wide writes with a read-modify-write
 111 * sequence, it's not practical to have write-without-read privs.
 112 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
 113 * arch/alpha/mm/fault.c)
 114 */
 115        /* xwr */
 116#define __P000  _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 117#define __P001  _PAGE_P(_PAGE_FOE | _PAGE_FOW)
 118#define __P010  _PAGE_P(_PAGE_FOE)
 119#define __P011  _PAGE_P(_PAGE_FOE)
 120#define __P100  _PAGE_P(_PAGE_FOW | _PAGE_FOR)
 121#define __P101  _PAGE_P(_PAGE_FOW)
 122#define __P110  _PAGE_P(0)
 123#define __P111  _PAGE_P(0)
 124
 125#define __S000  _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
 126#define __S001  _PAGE_S(_PAGE_FOE | _PAGE_FOW)
 127#define __S010  _PAGE_S(_PAGE_FOE)
 128#define __S011  _PAGE_S(_PAGE_FOE)
 129#define __S100  _PAGE_S(_PAGE_FOW | _PAGE_FOR)
 130#define __S101  _PAGE_S(_PAGE_FOW)
 131#define __S110  _PAGE_S(0)
 132#define __S111  _PAGE_S(0)
 133
 134/*
 135 * BAD_PAGETABLE is used when we need a bogus page-table, while
 136 * BAD_PAGE is used for a bogus page.
 137 *
 138 * ZERO_PAGE is a global shared page that is always zero:  used
 139 * for zero-mapped memory areas etc..
 140 */
 141extern pte_t __bad_page(void);
 142extern pmd_t * __bad_pagetable(void);
 143
 144extern unsigned long __zero_page(void);
 145
 146#define BAD_PAGETABLE   __bad_pagetable()
 147#define BAD_PAGE        __bad_page()
 148#define ZERO_PAGE(vaddr)        (virt_to_page(ZERO_PGE))
 149
 150/* number of bits that fit into a memory pointer */
 151#define BITS_PER_PTR                    (8*sizeof(unsigned long))
 152
 153/* to align the pointer to a pointer address */
 154#define PTR_MASK                        (~(sizeof(void*)-1))
 155
 156/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 157#define SIZEOF_PTR_LOG2                 3
 158
 159/* to find an entry in a page-table */
 160#define PAGE_PTR(address)               \
 161  ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 162
 163/*
 164 * On certain platforms whose physical address space can overlap KSEG,
 165 * namely EV6 and above, we must re-twiddle the physaddr to restore the
 166 * correct high-order bits.
 167 *
 168 * This is extremely confusing until you realize that this is actually
 169 * just working around a userspace bug.  The X server was intending to
 170 * provide the physical address but instead provided the KSEG address.
 171 * Or tried to, except it's not representable.
 172 * 
 173 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
 174 * a safe thing to do.  Come the first core logic that does put something
 175 * in this area -- memory or whathaveyou -- then this hack will have
 176 * to go away.  So be prepared!
 177 */
 178
 179#if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
 180#error "EV6-only feature in a generic kernel"
 181#endif
 182#if defined(CONFIG_ALPHA_GENERIC) || \
 183    (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
 184#define KSEG_PFN        (0xc0000000000UL >> PAGE_SHIFT)
 185#define PHYS_TWIDDLE(pfn) \
 186  ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
 187  ? ((pfn) ^= KSEG_PFN) : (pfn))
 188#else
 189#define PHYS_TWIDDLE(pfn) (pfn)
 190#endif
 191
 192/*
 193 * Conversion functions:  convert a page and protection to a page entry,
 194 * and a page entry and page directory to the page they refer to.
 195 */
 196#ifndef CONFIG_DISCONTIGMEM
 197#define page_to_pa(page)        (((page) - mem_map) << PAGE_SHIFT)
 198
 199#define pte_pfn(pte)    (pte_val(pte) >> 32)
 200#define pte_page(pte)   pfn_to_page(pte_pfn(pte))
 201#define mk_pte(page, pgprot)                                            \
 202({                                                                      \
 203        pte_t pte;                                                      \
 204                                                                        \
 205        pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot);  \
 206        pte;                                                            \
 207})
 208#endif
 209
 210extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
 211{ pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
 212
 213extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 214{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
 215
 216extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
 217{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 218
 219extern inline void pgd_set(pgd_t * pgdp, pmd_t * pmdp)
 220{ pgd_val(*pgdp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
 221
 222
 223extern inline unsigned long
 224pmd_page_kernel(pmd_t pmd)
 225{
 226        return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
 227}
 228
 229#ifndef CONFIG_DISCONTIGMEM
 230#define pmd_page(pmd)   (mem_map + ((pmd_val(pmd) & _PFN_MASK) >> 32))
 231#endif
 232
 233extern inline unsigned long pgd_page(pgd_t pgd)
 234{ return PAGE_OFFSET + ((pgd_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
 235
 236extern inline int pte_none(pte_t pte)           { return !pte_val(pte); }
 237extern inline int pte_present(pte_t pte)        { return pte_val(pte) & _PAGE_VALID; }
 238extern inline void pte_clear(pte_t *ptep)       { pte_val(*ptep) = 0; }
 239
 240extern inline int pmd_none(pmd_t pmd)           { return !pmd_val(pmd); }
 241extern inline int pmd_bad(pmd_t pmd)            { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
 242extern inline int pmd_present(pmd_t pmd)        { return pmd_val(pmd) & _PAGE_VALID; }
 243extern inline void pmd_clear(pmd_t * pmdp)      { pmd_val(*pmdp) = 0; }
 244
 245extern inline int pgd_none(pgd_t pgd)           { return !pgd_val(pgd); }
 246extern inline int pgd_bad(pgd_t pgd)            { return (pgd_val(pgd) & ~_PFN_MASK) != _PAGE_TABLE; }
 247extern inline int pgd_present(pgd_t pgd)        { return pgd_val(pgd) & _PAGE_VALID; }
 248extern inline void pgd_clear(pgd_t * pgdp)      { pgd_val(*pgdp) = 0; }
 249
 250/*
 251 * The following only work if pte_present() is true.
 252 * Undefined behaviour if not..
 253 */
 254extern inline int pte_read(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOR); }
 255extern inline int pte_write(pte_t pte)          { return !(pte_val(pte) & _PAGE_FOW); }
 256extern inline int pte_exec(pte_t pte)           { return !(pte_val(pte) & _PAGE_FOE); }
 257extern inline int pte_dirty(pte_t pte)          { return pte_val(pte) & _PAGE_DIRTY; }
 258extern inline int pte_young(pte_t pte)          { return pte_val(pte) & _PAGE_ACCESSED; }
 259extern inline int pte_file(pte_t pte)           { return pte_val(pte) & _PAGE_FILE; }
 260
 261extern inline pte_t pte_wrprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOW; return pte; }
 262extern inline pte_t pte_rdprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOR; return pte; }
 263extern inline pte_t pte_exprotect(pte_t pte)    { pte_val(pte) |= _PAGE_FOE; return pte; }
 264extern inline pte_t pte_mkclean(pte_t pte)      { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
 265extern inline pte_t pte_mkold(pte_t pte)        { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
 266extern inline pte_t pte_mkwrite(pte_t pte)      { pte_val(pte) &= ~_PAGE_FOW; return pte; }
 267extern inline pte_t pte_mkread(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOR; return pte; }
 268extern inline pte_t pte_mkexec(pte_t pte)       { pte_val(pte) &= ~_PAGE_FOE; return pte; }
 269extern inline pte_t pte_mkdirty(pte_t pte)      { pte_val(pte) |= __DIRTY_BITS; return pte; }
 270extern inline pte_t pte_mkyoung(pte_t pte)      { pte_val(pte) |= __ACCESS_BITS; return pte; }
 271
 272#define PAGE_DIR_OFFSET(tsk,address) pgd_offset((tsk),(address))
 273
 274/* to find an entry in a kernel page-table-directory */
 275#define pgd_offset_k(address) pgd_offset(&init_mm, (address))
 276
 277/* to find an entry in a page-table-directory. */
 278#define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 279#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 280
 281/* Find an entry in the second-level page table.. */
 282extern inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 283{
 284        return (pmd_t *) pgd_page(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
 285}
 286
 287/* Find an entry in the third-level page table.. */
 288extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
 289{
 290        return (pte_t *) pmd_page_kernel(*dir)
 291                + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
 292}
 293
 294#define pte_offset_map(dir,addr)        pte_offset_kernel((dir),(addr))
 295#define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir),(addr))
 296#define pte_unmap(pte)                  do { } while (0)
 297#define pte_unmap_nested(pte)           do { } while (0)
 298
 299extern pgd_t swapper_pg_dir[1024];
 300
 301/*
 302 * The Alpha doesn't have any external MMU info:  the kernel page
 303 * tables contain all the necessary information.
 304 */
 305extern inline void update_mmu_cache(struct vm_area_struct * vma,
 306        unsigned long address, pte_t pte)
 307{
 308}
 309
 310/*
 311 * Non-present pages:  high 24 bits are offset, next 8 bits type,
 312 * low 32 bits zero.
 313 */
 314extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 315{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 316
 317#define __swp_type(x)           (((x).val >> 32) & 0xff)
 318#define __swp_offset(x)         ((x).val >> 40)
 319#define __swp_entry(type, off)  ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
 320#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 321#define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 322
 323#define pte_to_pgoff(pte)       (pte_val(pte) >> 32)
 324#define pgoff_to_pte(off)       ((pte_t) { ((off) << 32) | _PAGE_FILE })
 325
 326#define PTE_FILE_MAX_BITS       32
 327
 328#ifndef CONFIG_DISCONTIGMEM
 329#define kern_addr_valid(addr)   (1)
 330#endif
 331
 332#define io_remap_page_range(vma, start, busaddr, size, prot)    \
 333({                                                              \
 334        void *va = (void __force *)ioremap(busaddr, size);      \
 335        unsigned long pfn = virt_to_phys(va) >> PAGE_SHIFT;     \
 336        remap_pfn_range(vma, start, pfn, size, prot);           \
 337})
 338
 339#define pte_ERROR(e) \
 340        printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 341#define pmd_ERROR(e) \
 342        printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 343#define pgd_ERROR(e) \
 344        printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 345
 346extern void paging_init(void);
 347
 348#include <asm-generic/pgtable.h>
 349
 350/*
 351 * No page table caches to initialise
 352 */
 353#define pgtable_cache_init()    do { } while (0)
 354
 355/* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
 356#define HAVE_ARCH_UNMAPPED_AREA
 357
 358#endif /* _ALPHA_PGTABLE_H */
 359