linux/arch/xtensa/include/asm/pgtable.h
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   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * include/asm-xtensa/pgtable.h
   4 *
   5 * Copyright (C) 2001 - 2013 Tensilica Inc.
   6 */
   7
   8#ifndef _XTENSA_PGTABLE_H
   9#define _XTENSA_PGTABLE_H
  10
  11#define __ARCH_USE_5LEVEL_HACK
  12#include <asm/page.h>
  13#include <asm/kmem_layout.h>
  14#include <asm-generic/pgtable-nopmd.h>
  15
  16/*
  17 * We only use two ring levels, user and kernel space.
  18 */
  19
  20#ifdef CONFIG_MMU
  21#define USER_RING               1       /* user ring level */
  22#else
  23#define USER_RING               0
  24#endif
  25#define KERNEL_RING             0       /* kernel ring level */
  26
  27/*
  28 * The Xtensa architecture port of Linux has a two-level page table system,
  29 * i.e. the logical three-level Linux page table layout is folded.
  30 * Each task has the following memory page tables:
  31 *
  32 *   PGD table (page directory), ie. 3rd-level page table:
  33 *      One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables
  34 *      (Architectures that don't have the PMD folded point to the PMD tables)
  35 *
  36 *      The pointer to the PGD table for a given task can be retrieved from
  37 *      the task structure (struct task_struct*) t, e.g. current():
  38 *        (t->mm ? t->mm : t->active_mm)->pgd
  39 *
  40 *   PMD tables (page middle-directory), ie. 2nd-level page tables:
  41 *      Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1).
  42 *
  43 *   PTE tables (page table entry), ie. 1st-level page tables:
  44 *      One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE
  45 *      invalid_pte_table for absent mappings.
  46 *
  47 * The individual pages are 4 kB big with special pages for the empty_zero_page.
  48 */
  49
  50#define PGDIR_SHIFT     22
  51#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  52#define PGDIR_MASK      (~(PGDIR_SIZE-1))
  53
  54/*
  55 * Entries per page directory level: we use two-level, so
  56 * we don't really have any PMD directory physically.
  57 */
  58#define PTRS_PER_PTE            1024
  59#define PTRS_PER_PTE_SHIFT      10
  60#define PTRS_PER_PGD            1024
  61#define PGD_ORDER               0
  62#define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
  63#define FIRST_USER_ADDRESS      0UL
  64#define FIRST_USER_PGD_NR       (FIRST_USER_ADDRESS >> PGDIR_SHIFT)
  65
  66#ifdef CONFIG_MMU
  67/*
  68 * Virtual memory area. We keep a distance to other memory regions to be
  69 * on the safe side. We also use this area for cache aliasing.
  70 */
  71#define VMALLOC_START           (XCHAL_KSEG_CACHED_VADDR - 0x10000000)
  72#define VMALLOC_END             (VMALLOC_START + 0x07FEFFFF)
  73#define TLBTEMP_BASE_1          (VMALLOC_END + 1)
  74#define TLBTEMP_BASE_2          (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE)
  75#if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE
  76#define TLBTEMP_SIZE            (2 * DCACHE_WAY_SIZE)
  77#else
  78#define TLBTEMP_SIZE            ICACHE_WAY_SIZE
  79#endif
  80
  81#else
  82
  83#define VMALLOC_START           __XTENSA_UL_CONST(0)
  84#define VMALLOC_END             __XTENSA_UL_CONST(0xffffffff)
  85
  86#endif
  87
  88/*
  89 * For the Xtensa architecture, the PTE layout is as follows:
  90 *
  91 *              31------12  11  10-9   8-6  5-4  3-2  1-0
  92 *              +-----------------------------------------+
  93 *              |           |   Software   |   HARDWARE   |
  94 *              |    PPN    |          ADW | RI |Attribute|
  95 *              +-----------------------------------------+
  96 *   pte_none   |             MBZ          | 01 | 11 | 00 |
  97 *              +-----------------------------------------+
  98 *   present    |    PPN    | 0 | 00 | ADW | RI | CA | wx |
  99 *              +- - - - - - - - - - - - - - - - - - - - -+
 100 *   (PAGE_NONE)|    PPN    | 0 | 00 | ADW | 01 | 11 | 11 |
 101 *              +-----------------------------------------+
 102 *   swap       |     index     |   type   | 01 | 11 | 00 |
 103 *              +-----------------------------------------+
 104 *
 105 * For T1050 hardware and earlier the layout differs for present and (PAGE_NONE)
 106 *              +-----------------------------------------+
 107 *   present    |    PPN    | 0 | 00 | ADW | RI | CA | w1 |
 108 *              +-----------------------------------------+
 109 *   (PAGE_NONE)|    PPN    | 0 | 00 | ADW | 01 | 01 | 00 |
 110 *              +-----------------------------------------+
 111 *
 112 *  Legend:
 113 *   PPN        Physical Page Number
 114 *   ADW        software: accessed (young) / dirty / writable
 115 *   RI         ring (0=privileged, 1=user, 2 and 3 are unused)
 116 *   CA         cache attribute: 00 bypass, 01 writeback, 10 writethrough
 117 *              (11 is invalid and used to mark pages that are not present)
 118 *   w          page is writable (hw)
 119 *   x          page is executable (hw)
 120 *   index      swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB)
 121 *              (note that the index is always non-zero)
 122 *   type       swap type (5 bits -> 32 types)
 123 *
 124 *  Notes:
 125 *   - (PROT_NONE) is a special case of 'present' but causes an exception for
 126 *     any access (read, write, and execute).
 127 *   - 'multihit-exception' has the highest priority of all MMU exceptions,
 128 *     so the ring must be set to 'RING_USER' even for 'non-present' pages.
 129 *   - on older hardware, the exectuable flag was not supported and
 130 *     used as a 'valid' flag, so it needs to be always set.
 131 *   - we need to keep track of certain flags in software (dirty and young)
 132 *     to do this, we use write exceptions and have a separate software w-flag.
 133 *   - attribute value 1101 (and 1111 on T1050 and earlier) is reserved
 134 */
 135
 136#define _PAGE_ATTRIB_MASK       0xf
 137
 138#define _PAGE_HW_EXEC           (1<<0)  /* hardware: page is executable */
 139#define _PAGE_HW_WRITE          (1<<1)  /* hardware: page is writable */
 140
 141#define _PAGE_CA_BYPASS         (0<<2)  /* bypass, non-speculative */
 142#define _PAGE_CA_WB             (1<<2)  /* write-back */
 143#define _PAGE_CA_WT             (2<<2)  /* write-through */
 144#define _PAGE_CA_MASK           (3<<2)
 145#define _PAGE_CA_INVALID        (3<<2)
 146
 147/* We use invalid attribute values to distinguish special pte entries */
 148#if XCHAL_HW_VERSION_MAJOR < 2000
 149#define _PAGE_HW_VALID          0x01    /* older HW needed this bit set */
 150#define _PAGE_NONE              0x04
 151#else
 152#define _PAGE_HW_VALID          0x00
 153#define _PAGE_NONE              0x0f
 154#endif
 155
 156#define _PAGE_USER              (1<<4)  /* user access (ring=1) */
 157
 158/* Software */
 159#define _PAGE_WRITABLE_BIT      6
 160#define _PAGE_WRITABLE          (1<<6)  /* software: page writable */
 161#define _PAGE_DIRTY             (1<<7)  /* software: page dirty */
 162#define _PAGE_ACCESSED          (1<<8)  /* software: page accessed (read) */
 163
 164#ifdef CONFIG_MMU
 165
 166#define _PAGE_CHG_MASK     (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 167#define _PAGE_PRESENT      (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED)
 168
 169#define PAGE_NONE          __pgprot(_PAGE_NONE | _PAGE_USER)
 170#define PAGE_COPY          __pgprot(_PAGE_PRESENT | _PAGE_USER)
 171#define PAGE_COPY_EXEC     __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
 172#define PAGE_READONLY      __pgprot(_PAGE_PRESENT | _PAGE_USER)
 173#define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
 174#define PAGE_SHARED        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE)
 175#define PAGE_SHARED_EXEC \
 176        __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC)
 177#define PAGE_KERNEL        __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE)
 178#define PAGE_KERNEL_RO     __pgprot(_PAGE_PRESENT)
 179#define PAGE_KERNEL_EXEC   __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC)
 180
 181#if (DCACHE_WAY_SIZE > PAGE_SIZE)
 182# define _PAGE_DIRECTORY   (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS)
 183#else
 184# define _PAGE_DIRECTORY   (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
 185#endif
 186
 187#else /* no mmu */
 188
 189# define _PAGE_CHG_MASK  (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 190# define PAGE_NONE       __pgprot(0)
 191# define PAGE_SHARED     __pgprot(0)
 192# define PAGE_COPY       __pgprot(0)
 193# define PAGE_READONLY   __pgprot(0)
 194# define PAGE_KERNEL     __pgprot(0)
 195
 196#endif
 197
 198/*
 199 * On certain configurations of Xtensa MMUs (eg. the initial Linux config),
 200 * the MMU can't do page protection for execute, and considers that the same as
 201 * read.  Also, write permissions may imply read permissions.
 202 * What follows is the closest we can get by reasonable means..
 203 * See linux/mm/mmap.c for protection_map[] array that uses these definitions.
 204 */
 205#define __P000  PAGE_NONE               /* private --- */
 206#define __P001  PAGE_READONLY           /* private --r */
 207#define __P010  PAGE_COPY               /* private -w- */
 208#define __P011  PAGE_COPY               /* private -wr */
 209#define __P100  PAGE_READONLY_EXEC      /* private x-- */
 210#define __P101  PAGE_READONLY_EXEC      /* private x-r */
 211#define __P110  PAGE_COPY_EXEC          /* private xw- */
 212#define __P111  PAGE_COPY_EXEC          /* private xwr */
 213
 214#define __S000  PAGE_NONE               /* shared  --- */
 215#define __S001  PAGE_READONLY           /* shared  --r */
 216#define __S010  PAGE_SHARED             /* shared  -w- */
 217#define __S011  PAGE_SHARED             /* shared  -wr */
 218#define __S100  PAGE_READONLY_EXEC      /* shared  x-- */
 219#define __S101  PAGE_READONLY_EXEC      /* shared  x-r */
 220#define __S110  PAGE_SHARED_EXEC        /* shared  xw- */
 221#define __S111  PAGE_SHARED_EXEC        /* shared  xwr */
 222
 223#ifndef __ASSEMBLY__
 224
 225#define pte_ERROR(e) \
 226        printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
 227#define pgd_ERROR(e) \
 228        printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 229
 230extern unsigned long empty_zero_page[1024];
 231
 232#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 233
 234#ifdef CONFIG_MMU
 235extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
 236extern void paging_init(void);
 237#else
 238# define swapper_pg_dir NULL
 239static inline void paging_init(void) { }
 240#endif
 241
 242/*
 243 * The pmd contains the kernel virtual address of the pte page.
 244 */
 245#define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK))
 246#define pmd_page(pmd) virt_to_page(pmd_val(pmd))
 247
 248/*
 249 * pte status.
 250 */
 251# define pte_none(pte)   (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER))
 252#if XCHAL_HW_VERSION_MAJOR < 2000
 253# define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)
 254#else
 255# define pte_present(pte)                                               \
 256        (((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)           \
 257         || ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE))
 258#endif
 259#define pte_clear(mm,addr,ptep)                                         \
 260        do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0)
 261
 262#define pmd_none(pmd)    (!pmd_val(pmd))
 263#define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK)
 264#define pmd_bad(pmd)     (pmd_val(pmd) & ~PAGE_MASK)
 265#define pmd_clear(pmdp)  do { set_pmd(pmdp, __pmd(0)); } while (0)
 266
 267static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; }
 268static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
 269static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
 270static inline int pte_special(pte_t pte) { return 0; }
 271
 272static inline pte_t pte_wrprotect(pte_t pte)    
 273        { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; }
 274static inline pte_t pte_mkclean(pte_t pte)
 275        { pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; }
 276static inline pte_t pte_mkold(pte_t pte)
 277        { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
 278static inline pte_t pte_mkdirty(pte_t pte)
 279        { pte_val(pte) |= _PAGE_DIRTY; return pte; }
 280static inline pte_t pte_mkyoung(pte_t pte)
 281        { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 282static inline pte_t pte_mkwrite(pte_t pte)
 283        { pte_val(pte) |= _PAGE_WRITABLE; return pte; }
 284static inline pte_t pte_mkspecial(pte_t pte)
 285        { return pte; }
 286
 287#define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CA_MASK))
 288
 289/*
 290 * Conversion functions: convert a page and protection to a page entry,
 291 * and a page entry and page directory to the page they refer to.
 292 */
 293
 294#define pte_pfn(pte)            (pte_val(pte) >> PAGE_SHIFT)
 295#define pte_same(a,b)           (pte_val(a) == pte_val(b))
 296#define pte_page(x)             pfn_to_page(pte_pfn(x))
 297#define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 298#define mk_pte(page, prot)      pfn_pte(page_to_pfn(page), prot)
 299
 300static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 301{
 302        return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 303}
 304
 305/*
 306 * Certain architectures need to do special things when pte's
 307 * within a page table are directly modified.  Thus, the following
 308 * hook is made available.
 309 */
 310static inline void update_pte(pte_t *ptep, pte_t pteval)
 311{
 312        *ptep = pteval;
 313#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
 314        __asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep));
 315#endif
 316
 317}
 318
 319struct mm_struct;
 320
 321static inline void
 322set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval)
 323{
 324        update_pte(ptep, pteval);
 325}
 326
 327static inline void set_pte(pte_t *ptep, pte_t pteval)
 328{
 329        update_pte(ptep, pteval);
 330}
 331
 332static inline void
 333set_pmd(pmd_t *pmdp, pmd_t pmdval)
 334{
 335        *pmdp = pmdval;
 336}
 337
 338struct vm_area_struct;
 339
 340static inline int
 341ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr,
 342                          pte_t *ptep)
 343{
 344        pte_t pte = *ptep;
 345        if (!pte_young(pte))
 346                return 0;
 347        update_pte(ptep, pte_mkold(pte));
 348        return 1;
 349}
 350
 351static inline pte_t
 352ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 353{
 354        pte_t pte = *ptep;
 355        pte_clear(mm, addr, ptep);
 356        return pte;
 357}
 358
 359static inline void
 360ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 361{
 362        pte_t pte = *ptep;
 363        update_pte(ptep, pte_wrprotect(pte));
 364}
 365
 366/* to find an entry in a kernel page-table-directory */
 367#define pgd_offset_k(address)   pgd_offset(&init_mm, address)
 368
 369/* to find an entry in a page-table-directory */
 370#define pgd_offset(mm,address)  ((mm)->pgd + pgd_index(address))
 371
 372#define pgd_index(address)      ((address) >> PGDIR_SHIFT)
 373
 374/* Find an entry in the second-level page table.. */
 375#define pmd_offset(dir,address) ((pmd_t*)(dir))
 376
 377/* Find an entry in the third-level page table.. */
 378#define pte_index(address)      (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 379#define pte_offset_kernel(dir,addr)                                     \
 380        ((pte_t*) pmd_page_vaddr(*(dir)) + pte_index(addr))
 381#define pte_offset_map(dir,addr)        pte_offset_kernel((dir),(addr))
 382#define pte_unmap(pte)          do { } while (0)
 383
 384
 385/*
 386 * Encode and decode a swap and file entry.
 387 */
 388#define SWP_TYPE_BITS           5
 389#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
 390
 391#define __swp_type(entry)       (((entry).val >> 6) & 0x1f)
 392#define __swp_offset(entry)     ((entry).val >> 11)
 393#define __swp_entry(type,offs)  \
 394        ((swp_entry_t){((type) << 6) | ((offs) << 11) | \
 395         _PAGE_CA_INVALID | _PAGE_USER})
 396#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 397#define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 398
 399#endif /*  !defined (__ASSEMBLY__) */
 400
 401
 402#ifdef __ASSEMBLY__
 403
 404/* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long),
 405 *                _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long),
 406 *                _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long)
 407 *                _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long)
 408 *
 409 * Note: We require an additional temporary register which can be the same as
 410 *       the register that holds the address.
 411 *
 412 * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr))
 413 *
 414 */
 415#define _PGD_INDEX(rt,rs)       extui   rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT
 416#define _PTE_INDEX(rt,rs)       extui   rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT
 417
 418#define _PGD_OFFSET(mm,adr,tmp)         l32i    mm, mm, MM_PGD;         \
 419                                        _PGD_INDEX(tmp, adr);           \
 420                                        addx4   mm, tmp, mm
 421
 422#define _PTE_OFFSET(pmd,adr,tmp)        _PTE_INDEX(tmp, adr);           \
 423                                        srli    pmd, pmd, PAGE_SHIFT;   \
 424                                        slli    pmd, pmd, PAGE_SHIFT;   \
 425                                        addx4   pmd, tmp, pmd
 426
 427#else
 428
 429#define kern_addr_valid(addr)   (1)
 430
 431extern  void update_mmu_cache(struct vm_area_struct * vma,
 432                              unsigned long address, pte_t *ptep);
 433
 434typedef pte_t *pte_addr_t;
 435
 436#endif /* !defined (__ASSEMBLY__) */
 437
 438#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 439#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 440#define __HAVE_ARCH_PTEP_SET_WRPROTECT
 441#define __HAVE_ARCH_PTEP_MKDIRTY
 442#define __HAVE_ARCH_PTE_SAME
 443/* We provide our own get_unmapped_area to cope with
 444 * SHM area cache aliasing for userland.
 445 */
 446#define HAVE_ARCH_UNMAPPED_AREA
 447
 448#include <asm-generic/pgtable.h>
 449
 450#endif /* _XTENSA_PGTABLE_H */
 451