include/asm-i386/pgtable.h

   1 #ifndef _I386_PGTABLE_H
   2 #define _I386_PGTABLE_H
   3
   4
   5 /*
   6  * The Linux memory management assumes a three-level page table setup. On
   7  * the i386, we use that, but "fold" the mid level into the top-level page
   8  * table, so that we physically have the same two-level page table as the
   9  * i386 mmu expects.
  10  *
  11  * This file contains the functions and defines necessary to modify and use
  12  * the i386 page table tree.
  13  */
  14 #ifndef __ASSEMBLY__
  15 #include <asm/processor.h>
  16 #include <asm/fixmap.h>
  17 #include <linux/threads.h>
  18
  19 #ifndef _I386_BITOPS_H
  20 #include <asm/bitops.h>
  21 #endif
  22
  23 #include <linux/slab.h>
  24 #include <linux/list.h>
  25 #include <linux/spinlock.h>
  26
  27 struct mm_struct;
  28 struct vm_area_struct;
  29
  30 /*
  31  * ZERO_PAGE is a global shared page that is always zero: used
  32  * for zero-mapped memory areas etc..
  33  */
  34 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  35 extern unsigned long empty_zero_page[1024];
  36 extern pgd_t swapper_pg_dir[1024];
  37 extern kmem_cache_t *pgd_cache;
  38 extern kmem_cache_t *pmd_cache;
  39 extern spinlock_t pgd_lock;
  40 extern struct page *pgd_list;
  41
  42 void pmd_ctor(void *, kmem_cache_t *, unsigned long);
  43 void pgd_ctor(void *, kmem_cache_t *, unsigned long);
  44 void pgd_dtor(void *, kmem_cache_t *, unsigned long);
  45 void pgtable_cache_init(void);
  46 void paging_init(void);
  47
  48 /*
  49  * The Linux x86 paging architecture is 'compile-time dual-mode', it
  50  * implements both the traditional 2-level x86 page tables and the
  51  * newer 3-level PAE-mode page tables.
  52  */
  53 #ifdef CONFIG_X86_PAE
  54 # include <asm/pgtable-3level-defs.h>
  55 # define PMD_SIZE       (1UL << PMD_SHIFT)
  56 # define PMD_MASK       (~(PMD_SIZE-1))
  57 #else
  58 # include <asm/pgtable-2level-defs.h>
  59 #endif
  60
  61 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  62 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  63
  64 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  65 #define FIRST_USER_ADDRESS      0
  66
  67 #define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
  68 #define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
  69
  70 #define TWOLEVEL_PGDIR_SHIFT    22
  71 #define BOOT_USER_PGD_PTRS (__PAGE_OFFSET >> TWOLEVEL_PGDIR_SHIFT)
  72 #define BOOT_KERNEL_PGD_PTRS (1024-BOOT_USER_PGD_PTRS)
  73
  74 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  75  * current 8MB value just means that there will be a 8MB "hole" after the
  76  * physical memory until the kernel virtual memory starts.  That means that
  77  * any out-of-bounds memory accesses will hopefully be caught.
  78  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
  79  * area for the same reason. ;)
  80  */
  81 #define VMALLOC_OFFSET  (8*1024*1024)
  82 #define VMALLOC_START   (((unsigned long) high_memory + vmalloc_earlyreserve + \
  83                         2*VMALLOC_OFFSET-1) & ~(VMALLOC_OFFSET-1))
  84 #ifdef CONFIG_HIGHMEM
  85 # define VMALLOC_END    (PKMAP_BASE-2*PAGE_SIZE)
  86 #else
  87 # define VMALLOC_END    (FIXADDR_START-2*PAGE_SIZE)
  88 #endif
  89
  90 /*
  91  * _PAGE_PSE set in the page directory entry just means that
  92  * the page directory entry points directly to a 4MB-aligned block of
  93  * memory.
  94  */
  95 #define _PAGE_BIT_PRESENT       0
  96 #define _PAGE_BIT_RW            1
  97 #define _PAGE_BIT_USER          2
  98 #define _PAGE_BIT_PWT           3
  99 #define _PAGE_BIT_PCD           4
 100 #define _PAGE_BIT_ACCESSED      5
 101 #define _PAGE_BIT_DIRTY         6
 102 #define _PAGE_BIT_PSE           7       /* 4 MB (or 2MB) page, Pentium+, if present.. */
 103 #define _PAGE_BIT_GLOBAL        8       /* Global TLB entry PPro+ */
 104 #define _PAGE_BIT_UNUSED1       9       /* available for programmer */
 105 #define _PAGE_BIT_UNUSED2       10
 106 #define _PAGE_BIT_UNUSED3       11
 107 #define _PAGE_BIT_NX            63
 108
 109 #define _PAGE_PRESENT   0x001
 110 #define _PAGE_RW        0x002
 111 #define _PAGE_USER      0x004
 112 #define _PAGE_PWT       0x008
 113 #define _PAGE_PCD       0x010
 114 #define _PAGE_ACCESSED  0x020
 115 #define _PAGE_DIRTY     0x040
 116 #define _PAGE_PSE       0x080   /* 4 MB (or 2MB) page, Pentium+, if present.. */
 117 #define _PAGE_GLOBAL    0x100   /* Global TLB entry PPro+ */
 118 #define _PAGE_UNUSED1   0x200   /* available for programmer */
 119 #define _PAGE_UNUSED2   0x400
 120 #define _PAGE_UNUSED3   0x800
 121
 122 /* If _PAGE_PRESENT is clear, we use these: */
 123 #define _PAGE_FILE      0x040   /* nonlinear file mapping, saved PTE; unset:swap */
 124 #define _PAGE_PROTNONE  0x080   /* if the user mapped it with PROT_NONE;
 125                                    pte_present gives true */
 126 #ifdef CONFIG_X86_PAE
 127 #define _PAGE_NX        (1ULL<<_PAGE_BIT_NX)
 128 #else
 129 #define _PAGE_NX        0
 130 #endif
 131
 132 #define _PAGE_TABLE     (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
 133 #define _KERNPG_TABLE   (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
 134 #define _PAGE_CHG_MASK  (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 135
 136 #define PAGE_NONE \
 137         __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
 138 #define PAGE_SHARED \
 139         __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
 140
 141 #define PAGE_SHARED_EXEC \
 142         __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
 143 #define PAGE_COPY_NOEXEC \
 144         __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX)
 145 #define PAGE_COPY_EXEC \
 146         __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
 147 #define PAGE_COPY \
 148         PAGE_COPY_NOEXEC
 149 #define PAGE_READONLY \
 150         __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX)
 151 #define PAGE_READONLY_EXEC \
 152         __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
 153
 154 #define _PAGE_KERNEL \
 155         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_NX)
 156 #define _PAGE_KERNEL_EXEC \
 157         (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
 158
 159 extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
 160 #define __PAGE_KERNEL_RO                (__PAGE_KERNEL & ~_PAGE_RW)
 161 #define __PAGE_KERNEL_NOCACHE           (__PAGE_KERNEL | _PAGE_PCD)
 162 #define __PAGE_KERNEL_LARGE             (__PAGE_KERNEL | _PAGE_PSE)
 163 #define __PAGE_KERNEL_LARGE_EXEC        (__PAGE_KERNEL_EXEC | _PAGE_PSE)
 164
 165 #define PAGE_KERNEL             __pgprot(__PAGE_KERNEL)
 166 #define PAGE_KERNEL_RO          __pgprot(__PAGE_KERNEL_RO)
 167 #define PAGE_KERNEL_EXEC        __pgprot(__PAGE_KERNEL_EXEC)
 168 #define PAGE_KERNEL_NOCACHE     __pgprot(__PAGE_KERNEL_NOCACHE)
 169 #define PAGE_KERNEL_LARGE       __pgprot(__PAGE_KERNEL_LARGE)
 170 #define PAGE_KERNEL_LARGE_EXEC  __pgprot(__PAGE_KERNEL_LARGE_EXEC)
 171
 172 /*
 173  * The i386 can't do page protection for execute, and considers that
 174  * the same are read. Also, write permissions imply read permissions.
 175  * This is the closest we can get..
 176  */
 177 #define __P000  PAGE_NONE
 178 #define __P001  PAGE_READONLY
 179 #define __P010  PAGE_COPY
 180 #define __P011  PAGE_COPY
 181 #define __P100  PAGE_READONLY_EXEC
 182 #define __P101  PAGE_READONLY_EXEC
 183 #define __P110  PAGE_COPY_EXEC
 184 #define __P111  PAGE_COPY_EXEC
 185
 186 #define __S000  PAGE_NONE
 187 #define __S001  PAGE_READONLY
 188 #define __S010  PAGE_SHARED
 189 #define __S011  PAGE_SHARED
 190 #define __S100  PAGE_READONLY_EXEC
 191 #define __S101  PAGE_READONLY_EXEC
 192 #define __S110  PAGE_SHARED_EXEC
 193 #define __S111  PAGE_SHARED_EXEC
 194
 195 /*
 196  * Define this if things work differently on an i386 and an i486:
 197  * it will (on an i486) warn about kernel memory accesses that are
 198  * done without a 'access_ok(VERIFY_WRITE,..)'
 199  */
 200 #undef TEST_ACCESS_OK
 201
 202 /* The boot page tables (all created as a single array) */
 203 extern unsigned long pg0[];
 204
 205 #define pte_present(x)  ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
 206
 207 /* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
 208 #define pmd_none(x)     (!(unsigned long)pmd_val(x))
 209 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
 210 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
 211
 212
 213 #define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
 214
 215 /*
 216  * The following only work if pte_present() is true.
 217  * Undefined behaviour if not..
 218  */
 219 static inline int pte_user(pte_t pte)           { return (pte).pte_low & _PAGE_USER; }
 220 static inline int pte_read(pte_t pte)           { return (pte).pte_low & _PAGE_USER; }
 221 static inline int pte_dirty(pte_t pte)          { return (pte).pte_low & _PAGE_DIRTY; }
 222 static inline int pte_young(pte_t pte)          { return (pte).pte_low & _PAGE_ACCESSED; }
 223 static inline int pte_write(pte_t pte)          { return (pte).pte_low & _PAGE_RW; }
 224 static inline int pte_huge(pte_t pte)           { return (pte).pte_low & _PAGE_PSE; }
 225
 226 /*
 227  * The following only works if pte_present() is not true.
 228  */
 229 static inline int pte_file(pte_t pte)           { return (pte).pte_low & _PAGE_FILE; }
 230
 231 static inline pte_t pte_rdprotect(pte_t pte)    { (pte).pte_low &= ~_PAGE_USER; return pte; }
 232 static inline pte_t pte_exprotect(pte_t pte)    { (pte).pte_low &= ~_PAGE_USER; return pte; }
 233 static inline pte_t pte_mkclean(pte_t pte)      { (pte).pte_low &= ~_PAGE_DIRTY; return pte; }
 234 static inline pte_t pte_mkold(pte_t pte)        { (pte).pte_low &= ~_PAGE_ACCESSED; return pte; }
 235 static inline pte_t pte_wrprotect(pte_t pte)    { (pte).pte_low &= ~_PAGE_RW; return pte; }
 236 static inline pte_t pte_mkread(pte_t pte)       { (pte).pte_low |= _PAGE_USER; return pte; }
 237 static inline pte_t pte_mkexec(pte_t pte)       { (pte).pte_low |= _PAGE_USER; return pte; }
 238 static inline pte_t pte_mkdirty(pte_t pte)      { (pte).pte_low |= _PAGE_DIRTY; return pte; }
 239 static inline pte_t pte_mkyoung(pte_t pte)      { (pte).pte_low |= _PAGE_ACCESSED; return pte; }
 240 static inline pte_t pte_mkwrite(pte_t pte)      { (pte).pte_low |= _PAGE_RW; return pte; }
 241 static inline pte_t pte_mkhuge(pte_t pte)       { (pte).pte_low |= _PAGE_PSE; return pte; }
 242
 243 #ifdef CONFIG_X86_PAE
 244 # include <asm/pgtable-3level.h>
 245 #else
 246 # include <asm/pgtable-2level.h>
 247 #endif
 248
 249 static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 250 {
 251         if (!pte_dirty(*ptep))
 252                 return 0;
 253         return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
 254 }
 255
 256 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 257 {
 258         if (!pte_young(*ptep))
 259                 return 0;
 260         return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);
 261 }
 262
 263 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full)
 264 {
 265         pte_t pte;
 266         if (full) {
 267                 pte = *ptep;
 268                 pte_clear(mm, addr, ptep);
 269         } else {
 270                 pte = ptep_get_and_clear(mm, addr, ptep);
 271         }
 272         return pte;
 273 }
 274
 275 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 276 {
 277         clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
 278 }
 279
 280 /*
 281  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
 282  *
 283  *  dst - pointer to pgd range anwhere on a pgd page
 284  *  src - ""
 285  *  count - the number of pgds to copy.
 286  *
 287  * dst and src can be on the same page, but the range must not overlap,
 288  * and must not cross a page boundary.
 289  */
 290 static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
 291 {
 292        memcpy(dst, src, count * sizeof(pgd_t));
 293 }
 294
 295 /*
 296  * Macro to mark a page protection value as "uncacheable".  On processors which do not support
 297  * it, this is a no-op.
 298  */
 299 #define pgprot_noncached(prot)  ((boot_cpu_data.x86 > 3)                                          \
 300                                  ? (__pgprot(pgprot_val(prot) | _PAGE_PCD | _PAGE_PWT)) : (prot))
 301
 302 /*
 303  * Conversion functions: convert a page and protection to a page entry,
 304  * and a page entry and page directory to the page they refer to.
 305  */
 306
 307 #define mk_pte(page, pgprot)    pfn_pte(page_to_pfn(page), (pgprot))
 308
 309 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 310 {
 311         pte.pte_low &= _PAGE_CHG_MASK;
 312         pte.pte_low |= pgprot_val(newprot);
 313 #ifdef CONFIG_X86_PAE
 314         /*
 315          * Chop off the NX bit (if present), and add the NX portion of
 316          * the newprot (if present):
 317          */
 318         pte.pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
 319         pte.pte_high |= (pgprot_val(newprot) >> 32) & \
 320                                         (__supported_pte_mask >> 32);
 321 #endif
 322         return pte;
 323 }
 324
 325 #define pmd_large(pmd) \
 326 ((pmd_val(pmd) & (_PAGE_PSE|_PAGE_PRESENT)) == (_PAGE_PSE|_PAGE_PRESENT))
 327
 328 /*
 329  * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
 330  *
 331  * this macro returns the index of the entry in the pgd page which would
 332  * control the given virtual address
 333  */
 334 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 335 #define pgd_index_k(addr) pgd_index(addr)
 336
 337 /*
 338  * pgd_offset() returns a (pgd_t *)
 339  * pgd_index() is used get the offset into the pgd page's array of pgd_t's;
 340  */
 341 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 342
 343 /*
 344  * a shortcut which implies the use of the kernel's pgd, instead
 345  * of a process's
 346  */
 347 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 348
 349 /*
 350  * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
 351  *
 352  * this macro returns the index of the entry in the pmd page which would
 353  * control the given virtual address
 354  */
 355 #define pmd_index(address) \
 356                 (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 357
 358 /*
 359  * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
 360  *
 361  * this macro returns the index of the entry in the pte page which would
 362  * control the given virtual address
 363  */
 364 #define pte_index(address) \
 365                 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 366 #define pte_offset_kernel(dir, address) \
 367         ((pte_t *) pmd_page_kernel(*(dir)) +  pte_index(address))
 368
 369 #define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 370
 371 #define pmd_page_kernel(pmd) \
 372                 ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 373
 374 /*
 375  * Helper function that returns the kernel pagetable entry controlling
 376  * the virtual address 'address'. NULL means no pagetable entry present.
 377  * NOTE: the return type is pte_t but if the pmd is PSE then we return it
 378  * as a pte too.
 379  */
 380 extern pte_t *lookup_address(unsigned long address);
 381
 382 /*
 383  * Make a given kernel text page executable/non-executable.
 384  * Returns the previous executability setting of that page (which
 385  * is used to restore the previous state). Used by the SMP bootup code.
 386  * NOTE: this is an __init function for security reasons.
 387  */
 388 #ifdef CONFIG_X86_PAE
 389  extern int set_kernel_exec(unsigned long vaddr, int enable);
 390 #else
 391  static inline int set_kernel_exec(unsigned long vaddr, int enable) { return 0;}
 392 #endif
 393
 394 extern void noexec_setup(const char *str);
 395
 396 #if defined(CONFIG_HIGHPTE)
 397 #define pte_offset_map(dir, address) \
 398         ((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE0) + pte_index(address))
 399 #define pte_offset_map_nested(dir, address) \
 400         ((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE1) + pte_index(address))
 401 #define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
 402 #define pte_unmap_nested(pte) kunmap_atomic(pte, KM_PTE1)
 403 #else
 404 #define pte_offset_map(dir, address) \
 405         ((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
 406 #define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
 407 #define pte_unmap(pte) do { } while (0)
 408 #define pte_unmap_nested(pte) do { } while (0)
 409 #endif
 410
 411 /*
 412  * The i386 doesn't have any external MMU info: the kernel page
 413  * tables contain all the necessary information.
 414  *
 415  * Also, we only update the dirty/accessed state if we set
 416  * the dirty bit by hand in the kernel, since the hardware
 417  * will do the accessed bit for us, and we don't want to
 418  * race with other CPU's that might be updating the dirty
 419  * bit at the same time.
 420  */
 421 #define update_mmu_cache(vma,address,pte) do { } while (0)
 422 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 423 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
 424         do {                                                              \
 425                 if (__dirty) {                                            \
 426                         (__ptep)->pte_low = (__entry).pte_low;            \
 427                         flush_tlb_page(__vma, __address);                 \
 428                 }                                                         \
 429         } while (0)
 430
 431 #endif /* !__ASSEMBLY__ */
 432
 433 #ifdef CONFIG_FLATMEM
 434 #define kern_addr_valid(addr)   (1)
 435 #endif /* CONFIG_FLATMEM */
 436
 437 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)         \
 438                 remap_pfn_range(vma, vaddr, pfn, size, prot)
 439
 440 #define MK_IOSPACE_PFN(space, pfn)      (pfn)
 441 #define GET_IOSPACE(pfn)                0
 442 #define GET_PFN(pfn)                    (pfn)
 443
 444 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 445 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 446 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 447 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 448 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 449 #define __HAVE_ARCH_PTE_SAME
 450 #include <asm-generic/pgtable.h>
 451
 452 #endif /* _I386_PGTABLE_H */