arch/openrisc/include/asm/pgtable.h

   1 /*
   2  * OpenRISC Linux
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * OpenRISC implementation:
   9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11  * et al.
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  */
  18
  19 /* or32 pgtable.h - macros and functions to manipulate page tables
  20  *
  21  * Based on:
  22  * include/asm-cris/pgtable.h
  23  */
  24
  25 #ifndef __ASM_OPENRISC_PGTABLE_H
  26 #define __ASM_OPENRISC_PGTABLE_H
  27
  28 #include <asm-generic/pgtable-nopmd.h>
  29
  30 #ifndef __ASSEMBLY__
  31 #include <asm/mmu.h>
  32 #include <asm/fixmap.h>
  33
  34 /*
  35  * The Linux memory management assumes a three-level page table setup. On
  36  * or32, we use that, but "fold" the mid level into the top-level page
  37  * table. Since the MMU TLB is software loaded through an interrupt, it
  38  * supports any page table structure, so we could have used a three-level
  39  * setup, but for the amounts of memory we normally use, a two-level is
  40  * probably more efficient.
  41  *
  42  * This file contains the functions and defines necessary to modify and use
  43  * the or32 page table tree.
  44  */
  45
  46 extern void paging_init(void);
  47
  48 /* Certain architectures need to do special things when pte's
  49  * within a page table are directly modified.  Thus, the following
  50  * hook is made available.
  51  */
  52 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
  53 #define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval)
  54 /*
  55  * (pmds are folded into pgds so this doesn't get actually called,
  56  * but the define is needed for a generic inline function.)
  57  */
  58 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
  59
  60 #define PGDIR_SHIFT     (PAGE_SHIFT + (PAGE_SHIFT-2))
  61 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  62 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  63
  64 /*
  65  * entries per page directory level: we use a two-level, so
  66  * we don't really have any PMD directory physically.
  67  * pointers are 4 bytes so we can use the page size and
  68  * divide it by 4 (shift by 2).
  69  */
  70 #define PTRS_PER_PTE    (1UL << (PAGE_SHIFT-2))
  71
  72 #define PTRS_PER_PGD    (1UL << (PAGE_SHIFT-2))
  73
  74 /* calculate how many PGD entries a user-level program can use
  75  * the first mappable virtual address is 0
  76  * (TASK_SIZE is the maximum virtual address space)
  77  */
  78
  79 #define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  80 #define FIRST_USER_ADDRESS      0
  81
  82 /*
  83  * Kernels own virtual memory area.
  84  */
  85
  86 /*
  87  * The size and location of the vmalloc area are chosen so that modules
  88  * placed in this area aren't more than a 28-bit signed offset from any
  89  * kernel functions that they may need.  This greatly simplifies handling
  90  * of the relocations for l.j and l.jal instructions as we don't need to
  91  * introduce any trampolines for reaching "distant" code.
  92  *
  93  * 64 MB of vmalloc area is comparable to what's available on other arches.
  94  */
  95
  96 #define VMALLOC_START   (PAGE_OFFSET-0x04000000)
  97 #define VMALLOC_END     (PAGE_OFFSET)
  98 #define VMALLOC_VMADDR(x) ((unsigned long)(x))
  99
 100 /* Define some higher level generic page attributes.
 101  *
 102  * If you change _PAGE_CI definition be sure to change it in
 103  * io.h for ioremap_nocache() too.
 104  */
 105
 106 /*
 107  * An OR32 PTE looks like this:
 108  *
 109  * |  31 ... 10 |  9  |  8 ... 6  |  5  |  4  |  3  |  2  |  1  |  0  |
 110  *  Phys pg.num    L     PP Index    D     A    WOM   WBC   CI    CC
 111  *
 112  *  L  : link
 113  *  PPI: Page protection index
 114  *  D  : Dirty
 115  *  A  : Accessed
 116  *  WOM: Weakly ordered memory
 117  *  WBC: Write-back cache
 118  *  CI : Cache inhibit
 119  *  CC : Cache coherent
 120  *
 121  * The protection bits below should correspond to the layout of the actual
 122  * PTE as per above
 123  */
 124
 125 #define _PAGE_CC       0x001 /* software: pte contains a translation */
 126 #define _PAGE_CI       0x002 /* cache inhibit          */
 127 #define _PAGE_WBC      0x004 /* write back cache       */
 128 #define _PAGE_FILE     0x004 /* set: pagecache, unset: swap (when !PRESENT) */
 129 #define _PAGE_WOM      0x008 /* weakly ordered memory  */
 130
 131 #define _PAGE_A        0x010 /* accessed               */
 132 #define _PAGE_D        0x020 /* dirty                  */
 133 #define _PAGE_URE      0x040 /* user read enable       */
 134 #define _PAGE_UWE      0x080 /* user write enable      */
 135
 136 #define _PAGE_SRE      0x100 /* superuser read enable  */
 137 #define _PAGE_SWE      0x200 /* superuser write enable */
 138 #define _PAGE_EXEC     0x400 /* software: page is executable */
 139 #define _PAGE_U_SHARED 0x800 /* software: page is shared in user space */
 140
 141 /* 0x001 is cache coherency bit, which should always be set to
 142  *       1 - for SMP (when we support it)
 143  *       0 - otherwise
 144  *
 145  * we just reuse this bit in software for _PAGE_PRESENT and
 146  * force it to 0 when loading it into TLB.
 147  */
 148 #define _PAGE_PRESENT  _PAGE_CC
 149 #define _PAGE_USER     _PAGE_URE
 150 #define _PAGE_WRITE    (_PAGE_UWE | _PAGE_SWE)
 151 #define _PAGE_DIRTY    _PAGE_D
 152 #define _PAGE_ACCESSED _PAGE_A
 153 #define _PAGE_NO_CACHE _PAGE_CI
 154 #define _PAGE_SHARED   _PAGE_U_SHARED
 155 #define _PAGE_READ     (_PAGE_URE | _PAGE_SRE)
 156
 157 #define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 158 #define _PAGE_BASE     (_PAGE_PRESENT | _PAGE_ACCESSED)
 159 #define _PAGE_ALL      (_PAGE_PRESENT | _PAGE_ACCESSED)
 160 #define _KERNPG_TABLE \
 161         (_PAGE_BASE | _PAGE_SRE | _PAGE_SWE | _PAGE_ACCESSED | _PAGE_DIRTY)
 162
 163 #define PAGE_NONE       __pgprot(_PAGE_ALL)
 164 #define PAGE_READONLY   __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE)
 165 #define PAGE_READONLY_X __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_EXEC)
 166 #define PAGE_SHARED \
 167         __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_UWE | _PAGE_SWE \
 168                  | _PAGE_SHARED)
 169 #define PAGE_SHARED_X \
 170         __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_UWE | _PAGE_SWE \
 171                  | _PAGE_SHARED | _PAGE_EXEC)
 172 #define PAGE_COPY       __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE)
 173 #define PAGE_COPY_X     __pgprot(_PAGE_ALL | _PAGE_URE | _PAGE_SRE | _PAGE_EXEC)
 174
 175 #define PAGE_KERNEL \
 176         __pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
 177                  | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC)
 178 #define PAGE_KERNEL_RO \
 179         __pgprot(_PAGE_ALL | _PAGE_SRE \
 180                  | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC)
 181 #define PAGE_KERNEL_NOCACHE \
 182         __pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
 183                  | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
 184
 185 #define __P000  PAGE_NONE
 186 #define __P001  PAGE_READONLY_X
 187 #define __P010  PAGE_COPY
 188 #define __P011  PAGE_COPY_X
 189 #define __P100  PAGE_READONLY
 190 #define __P101  PAGE_READONLY_X
 191 #define __P110  PAGE_COPY
 192 #define __P111  PAGE_COPY_X
 193
 194 #define __S000  PAGE_NONE
 195 #define __S001  PAGE_READONLY_X
 196 #define __S010  PAGE_SHARED
 197 #define __S011  PAGE_SHARED_X
 198 #define __S100  PAGE_READONLY
 199 #define __S101  PAGE_READONLY_X
 200 #define __S110  PAGE_SHARED
 201 #define __S111  PAGE_SHARED_X
 202
 203 /* zero page used for uninitialized stuff */
 204 extern unsigned long empty_zero_page[2048];
 205 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 206
 207 /* number of bits that fit into a memory pointer */
 208 #define BITS_PER_PTR                    (8*sizeof(unsigned long))
 209
 210 /* to align the pointer to a pointer address */
 211 #define PTR_MASK                        (~(sizeof(void *)-1))
 212
 213 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
 214 /* 64-bit machines, beware!  SRB. */
 215 #define SIZEOF_PTR_LOG2                 2
 216
 217 /* to find an entry in a page-table */
 218 #define PAGE_PTR(address) \
 219 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
 220
 221 /* to set the page-dir */
 222 #define SET_PAGE_DIR(tsk, pgdir)
 223
 224 #define pte_none(x)     (!pte_val(x))
 225 #define pte_present(x)  (pte_val(x) & _PAGE_PRESENT)
 226 #define pte_clear(mm, addr, xp) do { pte_val(*(xp)) = 0; } while (0)
 227
 228 #define pmd_none(x)     (!pmd_val(x))
 229 #define pmd_bad(x)      ((pmd_val(x) & (~PAGE_MASK)) != _KERNPG_TABLE)
 230 #define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
 231 #define pmd_clear(xp)   do { pmd_val(*(xp)) = 0; } while (0)
 232
 233 /*
 234  * The following only work if pte_present() is true.
 235  * Undefined behaviour if not..
 236  */
 237
 238 static inline int pte_read(pte_t pte)  { return pte_val(pte) & _PAGE_READ; }
 239 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITE; }
 240 static inline int pte_exec(pte_t pte)  { return pte_val(pte) & _PAGE_EXEC; }
 241 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
 242 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
 243 static inline int pte_file(pte_t pte)  { return pte_val(pte) & _PAGE_FILE; }
 244 static inline int pte_special(pte_t pte) { return 0; }
 245 static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
 246
 247 static inline pte_t pte_wrprotect(pte_t pte)
 248 {
 249         pte_val(pte) &= ~(_PAGE_WRITE);
 250         return pte;
 251 }
 252
 253 static inline pte_t pte_rdprotect(pte_t pte)
 254 {
 255         pte_val(pte) &= ~(_PAGE_READ);
 256         return pte;
 257 }
 258
 259 static inline pte_t pte_exprotect(pte_t pte)
 260 {
 261         pte_val(pte) &= ~(_PAGE_EXEC);
 262         return pte;
 263 }
 264
 265 static inline pte_t pte_mkclean(pte_t pte)
 266 {
 267         pte_val(pte) &= ~(_PAGE_DIRTY);
 268         return pte;
 269 }
 270
 271 static inline pte_t pte_mkold(pte_t pte)
 272 {
 273         pte_val(pte) &= ~(_PAGE_ACCESSED);
 274         return pte;
 275 }
 276
 277 static inline pte_t pte_mkwrite(pte_t pte)
 278 {
 279         pte_val(pte) |= _PAGE_WRITE;
 280         return pte;
 281 }
 282
 283 static inline pte_t pte_mkread(pte_t pte)
 284 {
 285         pte_val(pte) |= _PAGE_READ;
 286         return pte;
 287 }
 288
 289 static inline pte_t pte_mkexec(pte_t pte)
 290 {
 291         pte_val(pte) |= _PAGE_EXEC;
 292         return pte;
 293 }
 294
 295 static inline pte_t pte_mkdirty(pte_t pte)
 296 {
 297         pte_val(pte) |= _PAGE_DIRTY;
 298         return pte;
 299 }
 300
 301 static inline pte_t pte_mkyoung(pte_t pte)
 302 {
 303         pte_val(pte) |= _PAGE_ACCESSED;
 304         return pte;
 305 }
 306
 307 /*
 308  * Conversion functions: convert a page and protection to a page entry,
 309  * and a page entry and page directory to the page they refer to.
 310  */
 311
 312 /* What actually goes as arguments to the various functions is less than
 313  * obvious, but a rule of thumb is that struct page's goes as struct page *,
 314  * really physical DRAM addresses are unsigned long's, and DRAM "virtual"
 315  * addresses (the 0xc0xxxxxx's) goes as void *'s.
 316  */
 317
 318 static inline pte_t __mk_pte(void *page, pgprot_t pgprot)
 319 {
 320         pte_t pte;
 321         /* the PTE needs a physical address */
 322         pte_val(pte) = __pa(page) | pgprot_val(pgprot);
 323         return pte;
 324 }
 325
 326 #define mk_pte(page, pgprot) __mk_pte(page_address(page), (pgprot))
 327
 328 #define mk_pte_phys(physpage, pgprot) \
 329 ({                                                                      \
 330         pte_t __pte;                                                    \
 331                                                                         \
 332         pte_val(__pte) = (physpage) + pgprot_val(pgprot);               \
 333         __pte;                                                          \
 334 })
 335
 336 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 337 {
 338         pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
 339         return pte;
 340 }
 341
 342
 343 /*
 344  * pte_val refers to a page in the 0x0xxxxxxx physical DRAM interval
 345  * __pte_page(pte_val) refers to the "virtual" DRAM interval
 346  * pte_pagenr refers to the page-number counted starting from the virtual
 347  * DRAM start
 348  */
 349
 350 static inline unsigned long __pte_page(pte_t pte)
 351 {
 352         /* the PTE contains a physical address */
 353         return (unsigned long)__va(pte_val(pte) & PAGE_MASK);
 354 }
 355
 356 #define pte_pagenr(pte)         ((__pte_page(pte) - PAGE_OFFSET) >> PAGE_SHIFT)
 357
 358 /* permanent address of a page */
 359
 360 #define __page_address(page) (PAGE_OFFSET + (((page) - mem_map) << PAGE_SHIFT))
 361 #define pte_page(pte)           (mem_map+pte_pagenr(pte))
 362
 363 /*
 364  * only the pte's themselves need to point to physical DRAM (see above)
 365  * the pagetable links are purely handled within the kernel SW and thus
 366  * don't need the __pa and __va transformations.
 367  */
 368 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 369 {
 370         pmd_val(*pmdp) = _KERNPG_TABLE | (unsigned long) ptep;
 371 }
 372
 373 #define pmd_page(pmd)           (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
 374 #define pmd_page_kernel(pmd)    ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
 375
 376 /* to find an entry in a page-table-directory. */
 377 #define pgd_index(address)      ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 378
 379 #define __pgd_offset(address)   pgd_index(address)
 380
 381 #define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
 382
 383 /* to find an entry in a kernel page-table-directory */
 384 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 385
 386 #define __pmd_offset(address) \
 387         (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 388
 389 /*
 390  * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
 391  *
 392  * this macro returns the index of the entry in the pte page which would
 393  * control the given virtual address
 394  */
 395 #define __pte_offset(address)                   \
 396         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 397 #define pte_offset_kernel(dir, address)         \
 398         ((pte_t *) pmd_page_kernel(*(dir)) +  __pte_offset(address))
 399 #define pte_offset_map(dir, address)            \
 400         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 401 #define pte_offset_map_nested(dir, address)     \
 402         pte_offset_map(dir, address)
 403
 404 #define pte_unmap(pte)          do { } while (0)
 405 #define pte_unmap_nested(pte)   do { } while (0)
 406 #define pte_pfn(x)              ((unsigned long)(((x).pte)) >> PAGE_SHIFT)
 407 #define pfn_pte(pfn, prot)  __pte((((pfn) << PAGE_SHIFT)) | pgprot_val(prot))
 408
 409 #define pte_ERROR(e) \
 410         printk(KERN_ERR "%s:%d: bad pte %p(%08lx).\n", \
 411                __FILE__, __LINE__, &(e), pte_val(e))
 412 #define pgd_ERROR(e) \
 413         printk(KERN_ERR "%s:%d: bad pgd %p(%08lx).\n", \
 414                __FILE__, __LINE__, &(e), pgd_val(e))
 415
 416 extern pgd_t swapper_pg_dir[PTRS_PER_PGD]; /* defined in head.S */
 417
 418 /*
 419  * or32 doesn't have any external MMU info: the kernel page
 420  * tables contain all the necessary information.
 421  *
 422  * Actually I am not sure on what this could be used for.
 423  */
 424 static inline void update_mmu_cache(struct vm_area_struct *vma,
 425         unsigned long address, pte_t *pte)
 426 {
 427 }
 428
 429 /* __PHX__ FIXME, SWAP, this probably doesn't work */
 430
 431 /* Encode and de-code a swap entry (must be !pte_none(e) && !pte_present(e)) */
 432 /* Since the PAGE_PRESENT bit is bit 4, we can use the bits above */
 433
 434 #define __swp_type(x)                   (((x).val >> 5) & 0x7f)
 435 #define __swp_offset(x)                 ((x).val >> 12)
 436 #define __swp_entry(type, offset) \
 437         ((swp_entry_t) { ((type) << 5) | ((offset) << 12) })
 438 #define __pte_to_swp_entry(pte)         ((swp_entry_t) { pte_val(pte) })
 439 #define __swp_entry_to_pte(x)           ((pte_t) { (x).val })
 440
 441 /* Encode and decode a nonlinear file mapping entry */
 442
 443 #define PTE_FILE_MAX_BITS               26
 444 #define pte_to_pgoff(x)                 (pte_val(x) >> 6)
 445 #define pgoff_to_pte(x)                 __pte(((x) << 6) | _PAGE_FILE)
 446
 447 #define kern_addr_valid(addr)           (1)
 448
 449 #include <asm-generic/pgtable.h>
 450
 451 /*
 452  * No page table caches to initialise
 453  */
 454 #define pgtable_cache_init()            do { } while (0)
 455
 456 typedef pte_t *pte_addr_t;
 457
 458 #endif /* __ASSEMBLY__ */
 459 #endif /* __ASM_OPENRISC_PGTABLE_H */