include/asm-s390/pgtable.h

   1 /*
   2  *  include/asm-s390/pgtable.h
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Hartmut Penner (hp@de.ibm.com)
   7  *               Ulrich Weigand (weigand@de.ibm.com)
   8  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   9  *
  10  *  Derived from "include/asm-i386/pgtable.h"
  11  */
  12
  13 #ifndef _ASM_S390_PGTABLE_H
  14 #define _ASM_S390_PGTABLE_H
  15
  16 #include <asm-generic/4level-fixup.h>
  17
  18 /*
  19  * The Linux memory management assumes a three-level page table setup. For
  20  * s390 31 bit we "fold" the mid level into the top-level page table, so
  21  * that we physically have the same two-level page table as the s390 mmu
  22  * expects in 31 bit mode. For s390 64 bit we use three of the five levels
  23  * the hardware provides (region first and region second tables are not
  24  * used).
  25  *
  26  * The "pgd_xxx()" functions are trivial for a folded two-level
  27  * setup: the pgd is never bad, and a pmd always exists (as it's folded
  28  * into the pgd entry)
  29  *
  30  * This file contains the functions and defines necessary to modify and use
  31  * the S390 page table tree.
  32  */
  33 #ifndef __ASSEMBLY__
  34 #include <linux/mm_types.h>
  35 #include <asm/bug.h>
  36 #include <asm/processor.h>
  37
  38 struct vm_area_struct; /* forward declaration (include/linux/mm.h) */
  39 struct mm_struct;
  40
  41 extern pgd_t swapper_pg_dir[] __attribute__ ((aligned (4096)));
  42 extern void paging_init(void);
  43
  44 /*
  45  * The S390 doesn't have any external MMU info: the kernel page
  46  * tables contain all the necessary information.
  47  */
  48 #define update_mmu_cache(vma, address, pte)     do { } while (0)
  49
  50 /*
  51  * ZERO_PAGE is a global shared page that is always zero: used
  52  * for zero-mapped memory areas etc..
  53  */
  54 extern char empty_zero_page[PAGE_SIZE];
  55 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
  56 #endif /* !__ASSEMBLY__ */
  57
  58 /*
  59  * PMD_SHIFT determines the size of the area a second-level page
  60  * table can map
  61  * PGDIR_SHIFT determines what a third-level page table entry can map
  62  */
  63 #ifndef __s390x__
  64 # define PMD_SHIFT      22
  65 # define PGDIR_SHIFT    22
  66 #else /* __s390x__ */
  67 # define PMD_SHIFT      21
  68 # define PGDIR_SHIFT    31
  69 #endif /* __s390x__ */
  70
  71 #define PMD_SIZE        (1UL << PMD_SHIFT)
  72 #define PMD_MASK        (~(PMD_SIZE-1))
  73 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  74 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  75
  76 /*
  77  * entries per page directory level: the S390 is two-level, so
  78  * we don't really have any PMD directory physically.
  79  * for S390 segment-table entries are combined to one PGD
  80  * that leads to 1024 pte per pgd
  81  */
  82 #ifndef __s390x__
  83 # define PTRS_PER_PTE    1024
  84 # define PTRS_PER_PMD    1
  85 # define PTRS_PER_PGD    512
  86 #else /* __s390x__ */
  87 # define PTRS_PER_PTE    512
  88 # define PTRS_PER_PMD    1024
  89 # define PTRS_PER_PGD    2048
  90 #endif /* __s390x__ */
  91
  92 #define FIRST_USER_ADDRESS  0
  93
  94 #define pte_ERROR(e) \
  95         printk("%s:%d: bad pte %p.\n", __FILE__, __LINE__, (void *) pte_val(e))
  96 #define pmd_ERROR(e) \
  97         printk("%s:%d: bad pmd %p.\n", __FILE__, __LINE__, (void *) pmd_val(e))
  98 #define pgd_ERROR(e) \
  99         printk("%s:%d: bad pgd %p.\n", __FILE__, __LINE__, (void *) pgd_val(e))
 100
 101 #ifndef __ASSEMBLY__
 102 /*
 103  * Just any arbitrary offset to the start of the vmalloc VM area: the
 104  * current 8MB value just means that there will be a 8MB "hole" after the
 105  * physical memory until the kernel virtual memory starts.  That means that
 106  * any out-of-bounds memory accesses will hopefully be caught.
 107  * The vmalloc() routines leaves a hole of 4kB between each vmalloced
 108  * area for the same reason. ;)
 109  */
 110 extern unsigned long vmalloc_end;
 111 #define VMALLOC_OFFSET  (8*1024*1024)
 112 #define VMALLOC_START   (((unsigned long) high_memory + VMALLOC_OFFSET) \
 113                          & ~(VMALLOC_OFFSET-1))
 114 #define VMALLOC_END     vmalloc_end
 115
 116 /*
 117  * We need some free virtual space to be able to do vmalloc.
 118  * VMALLOC_MIN_SIZE defines the minimum size of the vmalloc
 119  * area. On a machine with 2GB memory we make sure that we
 120  * have at least 128MB free space for vmalloc. On a machine
 121  * with 4TB we make sure we have at least 128GB.
 122  */
 123 #ifndef __s390x__
 124 #define VMALLOC_MIN_SIZE        0x8000000UL
 125 #define VMALLOC_END_INIT        0x80000000UL
 126 #else /* __s390x__ */
 127 #define VMALLOC_MIN_SIZE        0x2000000000UL
 128 #define VMALLOC_END_INIT        0x40000000000UL
 129 #endif /* __s390x__ */
 130
 131 /*
 132  * A 31 bit pagetable entry of S390 has following format:
 133  *  |   PFRA          |    |  OS  |
 134  * 0                   0IP0
 135  * 00000000001111111111222222222233
 136  * 01234567890123456789012345678901
 137  *
 138  * I Page-Invalid Bit:    Page is not available for address-translation
 139  * P Page-Protection Bit: Store access not possible for page
 140  *
 141  * A 31 bit segmenttable entry of S390 has following format:
 142  *  |   P-table origin      |  |PTL
 143  * 0                         IC
 144  * 00000000001111111111222222222233
 145  * 01234567890123456789012345678901
 146  *
 147  * I Segment-Invalid Bit:    Segment is not available for address-translation
 148  * C Common-Segment Bit:     Segment is not private (PoP 3-30)
 149  * PTL Page-Table-Length:    Page-table length (PTL+1*16 entries -> up to 256)
 150  *
 151  * The 31 bit segmenttable origin of S390 has following format:
 152  *
 153  *  |S-table origin   |     | STL |
 154  * X                   **GPS
 155  * 00000000001111111111222222222233
 156  * 01234567890123456789012345678901
 157  *
 158  * X Space-Switch event:
 159  * G Segment-Invalid Bit:     *
 160  * P Private-Space Bit:       Segment is not private (PoP 3-30)
 161  * S Storage-Alteration:
 162  * STL Segment-Table-Length:  Segment-table length (STL+1*16 entries -> up to 2048)
 163  *
 164  * A 64 bit pagetable entry of S390 has following format:
 165  * |                     PFRA                         |0IP0|  OS  |
 166  * 0000000000111111111122222222223333333333444444444455555555556666
 167  * 0123456789012345678901234567890123456789012345678901234567890123
 168  *
 169  * I Page-Invalid Bit:    Page is not available for address-translation
 170  * P Page-Protection Bit: Store access not possible for page
 171  *
 172  * A 64 bit segmenttable entry of S390 has following format:
 173  * |        P-table origin                              |      TT
 174  * 0000000000111111111122222222223333333333444444444455555555556666
 175  * 0123456789012345678901234567890123456789012345678901234567890123
 176  *
 177  * I Segment-Invalid Bit:    Segment is not available for address-translation
 178  * C Common-Segment Bit:     Segment is not private (PoP 3-30)
 179  * P Page-Protection Bit: Store access not possible for page
 180  * TT Type 00
 181  *
 182  * A 64 bit region table entry of S390 has following format:
 183  * |        S-table origin                             |   TF  TTTL
 184  * 0000000000111111111122222222223333333333444444444455555555556666
 185  * 0123456789012345678901234567890123456789012345678901234567890123
 186  *
 187  * I Segment-Invalid Bit:    Segment is not available for address-translation
 188  * TT Type 01
 189  * TF
 190  * TL Table lenght
 191  *
 192  * The 64 bit regiontable origin of S390 has following format:
 193  * |      region table origon                          |       DTTL
 194  * 0000000000111111111122222222223333333333444444444455555555556666
 195  * 0123456789012345678901234567890123456789012345678901234567890123
 196  *
 197  * X Space-Switch event:
 198  * G Segment-Invalid Bit:
 199  * P Private-Space Bit:
 200  * S Storage-Alteration:
 201  * R Real space
 202  * TL Table-Length:
 203  *
 204  * A storage key has the following format:
 205  * | ACC |F|R|C|0|
 206  *  0   3 4 5 6 7
 207  * ACC: access key
 208  * F  : fetch protection bit
 209  * R  : referenced bit
 210  * C  : changed bit
 211  */
 212
 213 /* Hardware bits in the page table entry */
 214 #define _PAGE_RO        0x200           /* HW read-only bit  */
 215 #define _PAGE_INVALID   0x400           /* HW invalid bit    */
 216 #define _PAGE_SWT       0x001           /* SW pte type bit t */
 217 #define _PAGE_SWX       0x002           /* SW pte type bit x */
 218
 219 /* Six different types of pages. */
 220 #define _PAGE_TYPE_EMPTY        0x400
 221 #define _PAGE_TYPE_NONE         0x401
 222 #define _PAGE_TYPE_SWAP         0x403
 223 #define _PAGE_TYPE_FILE         0x601   /* bit 0x002 is used for offset !! */
 224 #define _PAGE_TYPE_RO           0x200
 225 #define _PAGE_TYPE_RW           0x000
 226
 227 /*
 228  * PTE type bits are rather complicated. handle_pte_fault uses pte_present,
 229  * pte_none and pte_file to find out the pte type WITHOUT holding the page
 230  * table lock. ptep_clear_flush on the other hand uses ptep_clear_flush to
 231  * invalidate a given pte. ipte sets the hw invalid bit and clears all tlbs
 232  * for the page. The page table entry is set to _PAGE_TYPE_EMPTY afterwards.
 233  * This change is done while holding the lock, but the intermediate step
 234  * of a previously valid pte with the hw invalid bit set can be observed by
 235  * handle_pte_fault. That makes it necessary that all valid pte types with
 236  * the hw invalid bit set must be distinguishable from the four pte types
 237  * empty, none, swap and file.
 238  *
 239  *                      irxt  ipte  irxt
 240  * _PAGE_TYPE_EMPTY     1000   ->   1000
 241  * _PAGE_TYPE_NONE      1001   ->   1001
 242  * _PAGE_TYPE_SWAP      1011   ->   1011
 243  * _PAGE_TYPE_FILE      11?1   ->   11?1
 244  * _PAGE_TYPE_RO        0100   ->   1100
 245  * _PAGE_TYPE_RW        0000   ->   1000
 246  *
 247  * pte_none is true for bits combinations 1000, 1100
 248  * pte_present is true for bits combinations 0000, 0010, 0100, 0110, 1001
 249  * pte_file is true for bits combinations 1101, 1111
 250  * swap pte is 1011 and 0001, 0011, 0101, 0111, 1010 and 1110 are invalid.
 251  */
 252
 253 #ifndef __s390x__
 254
 255 /* Bits in the segment table entry */
 256 #define _PAGE_TABLE_LEN 0xf            /* only full page-tables            */
 257 #define _PAGE_TABLE_COM 0x10           /* common page-table                */
 258 #define _PAGE_TABLE_INV 0x20           /* invalid page-table               */
 259 #define _SEG_PRESENT    0x001          /* Software (overlap with PTL)      */
 260
 261 /* Bits int the storage key */
 262 #define _PAGE_CHANGED    0x02          /* HW changed bit                   */
 263 #define _PAGE_REFERENCED 0x04          /* HW referenced bit                */
 264
 265 #define _USER_SEG_TABLE_LEN    0x7f    /* user-segment-table up to 2 GB    */
 266 #define _KERNEL_SEG_TABLE_LEN  0x7f    /* kernel-segment-table up to 2 GB  */
 267
 268 /*
 269  * User and Kernel pagetables are identical
 270  */
 271 #define _PAGE_TABLE     _PAGE_TABLE_LEN
 272 #define _KERNPG_TABLE   _PAGE_TABLE_LEN
 273
 274 /*
 275  * The Kernel segment-tables includes the User segment-table
 276  */
 277
 278 #define _SEGMENT_TABLE  (_USER_SEG_TABLE_LEN|0x80000000|0x100)
 279 #define _KERNSEG_TABLE  _KERNEL_SEG_TABLE_LEN
 280
 281 #define USER_STD_MASK   0x00000080UL
 282
 283 #else /* __s390x__ */
 284
 285 /* Bits in the segment table entry */
 286 #define _PMD_ENTRY_INV   0x20          /* invalid segment table entry      */
 287 #define _PMD_ENTRY       0x00
 288
 289 /* Bits in the region third table entry */
 290 #define _PGD_ENTRY_INV   0x20          /* invalid region table entry       */
 291 #define _PGD_ENTRY       0x07
 292
 293 /*
 294  * User and kernel page directory
 295  */
 296 #define _REGION_THIRD       0x4
 297 #define _REGION_THIRD_LEN   0x3
 298 #define _REGION_TABLE       (_REGION_THIRD|_REGION_THIRD_LEN|0x40|0x100)
 299 #define _KERN_REGION_TABLE  (_REGION_THIRD|_REGION_THIRD_LEN)
 300
 301 #define USER_STD_MASK           0x0000000000000080UL
 302
 303 /* Bits in the storage key */
 304 #define _PAGE_CHANGED    0x02          /* HW changed bit                   */
 305 #define _PAGE_REFERENCED 0x04          /* HW referenced bit                */
 306
 307 #endif /* __s390x__ */
 308
 309 /*
 310  * Page protection definitions.
 311  */
 312 #define PAGE_NONE       __pgprot(_PAGE_TYPE_NONE)
 313 #define PAGE_RO         __pgprot(_PAGE_TYPE_RO)
 314 #define PAGE_RW         __pgprot(_PAGE_TYPE_RW)
 315
 316 #define PAGE_KERNEL     PAGE_RW
 317 #define PAGE_COPY       PAGE_RO
 318
 319 /*
 320  * The S390 can't do page protection for execute, and considers that the
 321  * same are read. Also, write permissions imply read permissions. This is
 322  * the closest we can get..
 323  */
 324          /*xwr*/
 325 #define __P000  PAGE_NONE
 326 #define __P001  PAGE_RO
 327 #define __P010  PAGE_RO
 328 #define __P011  PAGE_RO
 329 #define __P100  PAGE_RO
 330 #define __P101  PAGE_RO
 331 #define __P110  PAGE_RO
 332 #define __P111  PAGE_RO
 333
 334 #define __S000  PAGE_NONE
 335 #define __S001  PAGE_RO
 336 #define __S010  PAGE_RW
 337 #define __S011  PAGE_RW
 338 #define __S100  PAGE_RO
 339 #define __S101  PAGE_RO
 340 #define __S110  PAGE_RW
 341 #define __S111  PAGE_RW
 342
 343 /*
 344  * Certain architectures need to do special things when PTEs
 345  * within a page table are directly modified.  Thus, the following
 346  * hook is made available.
 347  */
 348 static inline void set_pte(pte_t *pteptr, pte_t pteval)
 349 {
 350         *pteptr = pteval;
 351 }
 352 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 353
 354 /*
 355  * pgd/pmd/pte query functions
 356  */
 357 #ifndef __s390x__
 358
 359 static inline int pgd_present(pgd_t pgd) { return 1; }
 360 static inline int pgd_none(pgd_t pgd)    { return 0; }
 361 static inline int pgd_bad(pgd_t pgd)     { return 0; }
 362
 363 static inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _SEG_PRESENT; }
 364 static inline int pmd_none(pmd_t pmd)    { return pmd_val(pmd) & _PAGE_TABLE_INV; }
 365 static inline int pmd_bad(pmd_t pmd)
 366 {
 367         return (pmd_val(pmd) & (~PAGE_MASK & ~_PAGE_TABLE_INV)) != _PAGE_TABLE;
 368 }
 369
 370 #else /* __s390x__ */
 371
 372 static inline int pgd_present(pgd_t pgd)
 373 {
 374         return (pgd_val(pgd) & ~PAGE_MASK) == _PGD_ENTRY;
 375 }
 376
 377 static inline int pgd_none(pgd_t pgd)
 378 {
 379         return pgd_val(pgd) & _PGD_ENTRY_INV;
 380 }
 381
 382 static inline int pgd_bad(pgd_t pgd)
 383 {
 384         return (pgd_val(pgd) & (~PAGE_MASK & ~_PGD_ENTRY_INV)) != _PGD_ENTRY;
 385 }
 386
 387 static inline int pmd_present(pmd_t pmd)
 388 {
 389         return (pmd_val(pmd) & ~PAGE_MASK) == _PMD_ENTRY;
 390 }
 391
 392 static inline int pmd_none(pmd_t pmd)
 393 {
 394         return pmd_val(pmd) & _PMD_ENTRY_INV;
 395 }
 396
 397 static inline int pmd_bad(pmd_t pmd)
 398 {
 399         return (pmd_val(pmd) & (~PAGE_MASK & ~_PMD_ENTRY_INV)) != _PMD_ENTRY;
 400 }
 401
 402 #endif /* __s390x__ */
 403
 404 static inline int pte_none(pte_t pte)
 405 {
 406         return (pte_val(pte) & _PAGE_INVALID) && !(pte_val(pte) & _PAGE_SWT);
 407 }
 408
 409 static inline int pte_present(pte_t pte)
 410 {
 411         unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT | _PAGE_SWX;
 412         return (pte_val(pte) & mask) == _PAGE_TYPE_NONE ||
 413                 (!(pte_val(pte) & _PAGE_INVALID) &&
 414                  !(pte_val(pte) & _PAGE_SWT));
 415 }
 416
 417 static inline int pte_file(pte_t pte)
 418 {
 419         unsigned long mask = _PAGE_RO | _PAGE_INVALID | _PAGE_SWT;
 420         return (pte_val(pte) & mask) == _PAGE_TYPE_FILE;
 421 }
 422
 423 #define pte_same(a,b)   (pte_val(a) == pte_val(b))
 424
 425 /*
 426  * query functions pte_write/pte_dirty/pte_young only work if
 427  * pte_present() is true. Undefined behaviour if not..
 428  */
 429 static inline int pte_write(pte_t pte)
 430 {
 431         return (pte_val(pte) & _PAGE_RO) == 0;
 432 }
 433
 434 static inline int pte_dirty(pte_t pte)
 435 {
 436         /* A pte is neither clean nor dirty on s/390. The dirty bit
 437          * is in the storage key. See page_test_and_clear_dirty for
 438          * details.
 439          */
 440         return 0;
 441 }
 442
 443 static inline int pte_young(pte_t pte)
 444 {
 445         /* A pte is neither young nor old on s/390. The young bit
 446          * is in the storage key. See page_test_and_clear_young for
 447          * details.
 448          */
 449         return 0;
 450 }
 451
 452 static inline int pte_read(pte_t pte)
 453 {
 454         /* All pages are readable since we don't use the fetch
 455          * protection bit in the storage key.
 456          */
 457         return 1;
 458 }
 459
 460 /*
 461  * pgd/pmd/pte modification functions
 462  */
 463
 464 #ifndef __s390x__
 465
 466 static inline void pgd_clear(pgd_t * pgdp)      { }
 467
 468 static inline void pmd_clear(pmd_t * pmdp)
 469 {
 470         pmd_val(pmdp[0]) = _PAGE_TABLE_INV;
 471         pmd_val(pmdp[1]) = _PAGE_TABLE_INV;
 472         pmd_val(pmdp[2]) = _PAGE_TABLE_INV;
 473         pmd_val(pmdp[3]) = _PAGE_TABLE_INV;
 474 }
 475
 476 #else /* __s390x__ */
 477
 478 static inline void pgd_clear(pgd_t * pgdp)
 479 {
 480         pgd_val(*pgdp) = _PGD_ENTRY_INV | _PGD_ENTRY;
 481 }
 482
 483 static inline void pmd_clear(pmd_t * pmdp)
 484 {
 485         pmd_val(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
 486         pmd_val1(*pmdp) = _PMD_ENTRY_INV | _PMD_ENTRY;
 487 }
 488
 489 #endif /* __s390x__ */
 490
 491 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 492 {
 493         pte_val(*ptep) = _PAGE_TYPE_EMPTY;
 494 }
 495
 496 /*
 497  * The following pte modification functions only work if
 498  * pte_present() is true. Undefined behaviour if not..
 499  */
 500 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 501 {
 502         pte_val(pte) &= PAGE_MASK;
 503         pte_val(pte) |= pgprot_val(newprot);
 504         return pte;
 505 }
 506
 507 static inline pte_t pte_wrprotect(pte_t pte)
 508 {
 509         /* Do not clobber _PAGE_TYPE_NONE pages!  */
 510         if (!(pte_val(pte) & _PAGE_INVALID))
 511                 pte_val(pte) |= _PAGE_RO;
 512         return pte;
 513 }
 514
 515 static inline pte_t pte_mkwrite(pte_t pte)
 516 {
 517         pte_val(pte) &= ~_PAGE_RO;
 518         return pte;
 519 }
 520
 521 static inline pte_t pte_mkclean(pte_t pte)
 522 {
 523         /* The only user of pte_mkclean is the fork() code.
 524            We must *not* clear the *physical* page dirty bit
 525            just because fork() wants to clear the dirty bit in
 526            *one* of the page's mappings.  So we just do nothing. */
 527         return pte;
 528 }
 529
 530 static inline pte_t pte_mkdirty(pte_t pte)
 531 {
 532         /* We do not explicitly set the dirty bit because the
 533          * sske instruction is slow. It is faster to let the
 534          * next instruction set the dirty bit.
 535          */
 536         return pte;
 537 }
 538
 539 static inline pte_t pte_mkold(pte_t pte)
 540 {
 541         /* S/390 doesn't keep its dirty/referenced bit in the pte.
 542          * There is no point in clearing the real referenced bit.
 543          */
 544         return pte;
 545 }
 546
 547 static inline pte_t pte_mkyoung(pte_t pte)
 548 {
 549         /* S/390 doesn't keep its dirty/referenced bit in the pte.
 550          * There is no point in setting the real referenced bit.
 551          */
 552         return pte;
 553 }
 554
 555 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 556 {
 557         return 0;
 558 }
 559
 560 static inline int
 561 ptep_clear_flush_young(struct vm_area_struct *vma,
 562                         unsigned long address, pte_t *ptep)
 563 {
 564         /* No need to flush TLB; bits are in storage key */
 565         return ptep_test_and_clear_young(vma, address, ptep);
 566 }
 567
 568 static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 569 {
 570         return 0;
 571 }
 572
 573 static inline int
 574 ptep_clear_flush_dirty(struct vm_area_struct *vma,
 575                         unsigned long address, pte_t *ptep)
 576 {
 577         /* No need to flush TLB; bits are in storage key */
 578         return ptep_test_and_clear_dirty(vma, address, ptep);
 579 }
 580
 581 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 582 {
 583         pte_t pte = *ptep;
 584         pte_clear(mm, addr, ptep);
 585         return pte;
 586 }
 587
 588 static inline void __ptep_ipte(unsigned long address, pte_t *ptep)
 589 {
 590         if (!(pte_val(*ptep) & _PAGE_INVALID)) {
 591 #ifndef __s390x__
 592                 /* S390 has 1mb segments, we are emulating 4MB segments */
 593                 pte_t *pto = (pte_t *) (((unsigned long) ptep) & 0x7ffffc00);
 594 #else
 595                 /* ipte in zarch mode can do the math */
 596                 pte_t *pto = ptep;
 597 #endif
 598                 asm volatile(
 599                         "       ipte    %2,%3"
 600                         : "=m" (*ptep) : "m" (*ptep),
 601                           "a" (pto), "a" (address));
 602         }
 603         pte_val(*ptep) = _PAGE_TYPE_EMPTY;
 604 }
 605
 606 static inline pte_t
 607 ptep_clear_flush(struct vm_area_struct *vma,
 608                  unsigned long address, pte_t *ptep)
 609 {
 610         pte_t pte = *ptep;
 611
 612         __ptep_ipte(address, ptep);
 613         return pte;
 614 }
 615
 616 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 617 {
 618         pte_t old_pte = *ptep;
 619         set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte));
 620 }
 621
 622 static inline void
 623 ptep_establish(struct vm_area_struct *vma,
 624                unsigned long address, pte_t *ptep,
 625                pte_t entry)
 626 {
 627         ptep_clear_flush(vma, address, ptep);
 628         set_pte(ptep, entry);
 629 }
 630
 631 #define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
 632         ptep_establish(__vma, __address, __ptep, __entry)
 633
 634 /*
 635  * Test and clear dirty bit in storage key.
 636  * We can't clear the changed bit atomically. This is a potential
 637  * race against modification of the referenced bit. This function
 638  * should therefore only be called if it is not mapped in any
 639  * address space.
 640  */
 641 static inline int page_test_and_clear_dirty(struct page *page)
 642 {
 643         unsigned long physpage = page_to_phys(page);
 644         int skey = page_get_storage_key(physpage);
 645
 646         if (skey & _PAGE_CHANGED)
 647                 page_set_storage_key(physpage, skey & ~_PAGE_CHANGED);
 648         return skey & _PAGE_CHANGED;
 649 }
 650
 651 /*
 652  * Test and clear referenced bit in storage key.
 653  */
 654 static inline int page_test_and_clear_young(struct page *page)
 655 {
 656         unsigned long physpage = page_to_phys(page);
 657         int ccode;
 658
 659         asm volatile(
 660                 "       rrbe    0,%1\n"
 661                 "       ipm     %0\n"
 662                 "       srl     %0,28\n"
 663                 : "=d" (ccode) : "a" (physpage) : "cc" );
 664         return ccode & 2;
 665 }
 666
 667 /*
 668  * Conversion functions: convert a page and protection to a page entry,
 669  * and a page entry and page directory to the page they refer to.
 670  */
 671 static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
 672 {
 673         pte_t __pte;
 674         pte_val(__pte) = physpage + pgprot_val(pgprot);
 675         return __pte;
 676 }
 677
 678 static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)
 679 {
 680         unsigned long physpage = page_to_phys(page);
 681
 682         return mk_pte_phys(physpage, pgprot);
 683 }
 684
 685 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 686 {
 687         unsigned long physpage = __pa((pfn) << PAGE_SHIFT);
 688
 689         return mk_pte_phys(physpage, pgprot);
 690 }
 691
 692 #ifdef __s390x__
 693
 694 static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
 695 {
 696         unsigned long physpage = __pa((pfn) << PAGE_SHIFT);
 697
 698         return __pmd(physpage + pgprot_val(pgprot));
 699 }
 700
 701 #endif /* __s390x__ */
 702
 703 #define pte_pfn(x) (pte_val(x) >> PAGE_SHIFT)
 704 #define pte_page(x) pfn_to_page(pte_pfn(x))
 705
 706 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK)
 707
 708 #define pmd_page(pmd) pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
 709
 710 #define pgd_page_vaddr(pgd) (pgd_val(pgd) & PAGE_MASK)
 711
 712 #define pgd_page(pgd) pfn_to_page(pgd_val(pgd) >> PAGE_SHIFT)
 713
 714 /* to find an entry in a page-table-directory */
 715 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 716 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 717
 718 /* to find an entry in a kernel page-table-directory */
 719 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 720
 721 #ifndef __s390x__
 722
 723 /* Find an entry in the second-level page table.. */
 724 static inline pmd_t * pmd_offset(pgd_t * dir, unsigned long address)
 725 {
 726         return (pmd_t *) dir;
 727 }
 728
 729 #else /* __s390x__ */
 730
 731 /* Find an entry in the second-level page table.. */
 732 #define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 733 #define pmd_offset(dir,addr) \
 734         ((pmd_t *) pgd_page_vaddr(*(dir)) + pmd_index(addr))
 735
 736 #endif /* __s390x__ */
 737
 738 /* Find an entry in the third-level page table.. */
 739 #define pte_index(address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1))
 740 #define pte_offset_kernel(pmd, address) \
 741         ((pte_t *) pmd_page_vaddr(*(pmd)) + pte_index(address))
 742 #define pte_offset_map(pmd, address) pte_offset_kernel(pmd, address)
 743 #define pte_offset_map_nested(pmd, address) pte_offset_kernel(pmd, address)
 744 #define pte_unmap(pte) do { } while (0)
 745 #define pte_unmap_nested(pte) do { } while (0)
 746
 747 /*
 748  * 31 bit swap entry format:
 749  * A page-table entry has some bits we have to treat in a special way.
 750  * Bits 0, 20 and bit 23 have to be zero, otherwise an specification
 751  * exception will occur instead of a page translation exception. The
 752  * specifiation exception has the bad habit not to store necessary
 753  * information in the lowcore.
 754  * Bit 21 and bit 22 are the page invalid bit and the page protection
 755  * bit. We set both to indicate a swapped page.
 756  * Bit 30 and 31 are used to distinguish the different page types. For
 757  * a swapped page these bits need to be zero.
 758  * This leaves the bits 1-19 and bits 24-29 to store type and offset.
 759  * We use the 5 bits from 25-29 for the type and the 20 bits from 1-19
 760  * plus 24 for the offset.
 761  * 0|     offset        |0110|o|type |00|
 762  * 0 0000000001111111111 2222 2 22222 33
 763  * 0 1234567890123456789 0123 4 56789 01
 764  *
 765  * 64 bit swap entry format:
 766  * A page-table entry has some bits we have to treat in a special way.
 767  * Bits 52 and bit 55 have to be zero, otherwise an specification
 768  * exception will occur instead of a page translation exception. The
 769  * specifiation exception has the bad habit not to store necessary
 770  * information in the lowcore.
 771  * Bit 53 and bit 54 are the page invalid bit and the page protection
 772  * bit. We set both to indicate a swapped page.
 773  * Bit 62 and 63 are used to distinguish the different page types. For
 774  * a swapped page these bits need to be zero.
 775  * This leaves the bits 0-51 and bits 56-61 to store type and offset.
 776  * We use the 5 bits from 57-61 for the type and the 53 bits from 0-51
 777  * plus 56 for the offset.
 778  * |                      offset                        |0110|o|type |00|
 779  *  0000000000111111111122222222223333333333444444444455 5555 5 55566 66
 780  *  0123456789012345678901234567890123456789012345678901 2345 6 78901 23
 781  */
 782 #ifndef __s390x__
 783 #define __SWP_OFFSET_MASK (~0UL >> 12)
 784 #else
 785 #define __SWP_OFFSET_MASK (~0UL >> 11)
 786 #endif
 787 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 788 {
 789         pte_t pte;
 790         offset &= __SWP_OFFSET_MASK;
 791         pte_val(pte) = _PAGE_TYPE_SWAP | ((type & 0x1f) << 2) |
 792                 ((offset & 1UL) << 7) | ((offset & ~1UL) << 11);
 793         return pte;
 794 }
 795
 796 #define __swp_type(entry)       (((entry).val >> 2) & 0x1f)
 797 #define __swp_offset(entry)     (((entry).val >> 11) | (((entry).val >> 7) & 1))
 798 #define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
 799
 800 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 801 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 802
 803 #ifndef __s390x__
 804 # define PTE_FILE_MAX_BITS      26
 805 #else /* __s390x__ */
 806 # define PTE_FILE_MAX_BITS      59
 807 #endif /* __s390x__ */
 808
 809 #define pte_to_pgoff(__pte) \
 810         ((((__pte).pte >> 12) << 7) + (((__pte).pte >> 1) & 0x7f))
 811
 812 #define pgoff_to_pte(__off) \
 813         ((pte_t) { ((((__off) & 0x7f) << 1) + (((__off) >> 7) << 12)) \
 814                    | _PAGE_TYPE_FILE })
 815
 816 #endif /* !__ASSEMBLY__ */
 817
 818 #define kern_addr_valid(addr)   (1)
 819
 820 extern int add_shared_memory(unsigned long start, unsigned long size);
 821 extern int remove_shared_memory(unsigned long start, unsigned long size);
 822
 823 /*
 824  * No page table caches to initialise
 825  */
 826 #define pgtable_cache_init()    do { } while (0)
 827
 828 #define __HAVE_ARCH_MEMMAP_INIT
 829 extern void memmap_init(unsigned long, int, unsigned long, unsigned long);
 830
 831 #define __HAVE_ARCH_PTEP_ESTABLISH
 832 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 833 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 834 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 835 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
 836 #define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
 837 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 838 #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
 839 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 840 #define __HAVE_ARCH_PTE_SAME
 841 #define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
 842 #define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
 843 #include <asm-generic/pgtable.h>
 844
 845 #endif /* _S390_PAGE_H */
 846