LXR linux/arch/arm/include/asm/pgtable-3level.h

   1/*
   2 * arch/arm/include/asm/pgtable-3level.h
   3 *
   4 * Copyright (C) 2011 ARM Ltd.
   5 * Author: Catalin Marinas <catalin.marinas@arm.com>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 */
  20#ifndef _ASM_PGTABLE_3LEVEL_H
  21#define _ASM_PGTABLE_3LEVEL_H
  22
  23/*
  24 * With LPAE, there are 3 levels of page tables. Each level has 512 entries of
  25 * 8 bytes each, occupying a 4K page. The first level table covers a range of
  26 * 512GB, each entry representing 1GB. Since we are limited to 4GB input
  27 * address range, only 4 entries in the PGD are used.
  28 *
  29 * There are enough spare bits in a page table entry for the kernel specific
  30 * state.
  31 */
  32#define PTRS_PER_PTE            512
  33#define PTRS_PER_PMD            512
  34#define PTRS_PER_PGD            4
  35
  36#define PTE_HWTABLE_PTRS        (0)
  37#define PTE_HWTABLE_OFF         (0)
  38#define PTE_HWTABLE_SIZE        (PTRS_PER_PTE * sizeof(u64))
  39
  40/*
  41 * PGDIR_SHIFT determines the size a top-level page table entry can map.
  42 */
  43#define PGDIR_SHIFT             30
  44
  45/*
  46 * PMD_SHIFT determines the size a middle-level page table entry can map.
  47 */
  48#define PMD_SHIFT               21
  49
  50#define PMD_SIZE                (1UL << PMD_SHIFT)
  51#define PMD_MASK                (~((1 << PMD_SHIFT) - 1))
  52#define PGDIR_SIZE              (1UL << PGDIR_SHIFT)
  53#define PGDIR_MASK              (~((1 << PGDIR_SHIFT) - 1))
  54
  55/*
  56 * section address mask and size definitions.
  57 */
  58#define SECTION_SHIFT           21
  59#define SECTION_SIZE            (1UL << SECTION_SHIFT)
  60#define SECTION_MASK            (~((1 << SECTION_SHIFT) - 1))
  61
  62#define USER_PTRS_PER_PGD       (PAGE_OFFSET / PGDIR_SIZE)
  63
  64/*
  65 * Hugetlb definitions.
  66 */
  67#define HPAGE_SHIFT             PMD_SHIFT
  68#define HPAGE_SIZE              (_AC(1, UL) << HPAGE_SHIFT)
  69#define HPAGE_MASK              (~(HPAGE_SIZE - 1))
  70#define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
  71
  72/*
  73 * "Linux" PTE definitions for LPAE.
  74 *
  75 * These bits overlap with the hardware bits but the naming is preserved for
  76 * consistency with the classic page table format.
  77 */
  78#define L_PTE_VALID             (_AT(pteval_t, 1) << 0)         /* Valid */
  79#define L_PTE_PRESENT           (_AT(pteval_t, 3) << 0)         /* Present */
  80#define L_PTE_FILE              (_AT(pteval_t, 1) << 2)         /* only when !PRESENT */
  81#define L_PTE_USER              (_AT(pteval_t, 1) << 6)         /* AP[1] */
  82#define L_PTE_RDONLY            (_AT(pteval_t, 1) << 7)         /* AP[2] */
  83#define L_PTE_SHARED            (_AT(pteval_t, 3) << 8)         /* SH[1:0], inner shareable */
  84#define L_PTE_YOUNG             (_AT(pteval_t, 1) << 10)        /* AF */
  85#define L_PTE_XN                (_AT(pteval_t, 1) << 54)        /* XN */
  86#define L_PTE_DIRTY             (_AT(pteval_t, 1) << 55)        /* unused */
  87#define L_PTE_SPECIAL           (_AT(pteval_t, 1) << 56)        /* unused */
  88#define L_PTE_NONE              (_AT(pteval_t, 1) << 57)        /* PROT_NONE */
  89
  90#define PMD_SECT_VALID          (_AT(pmdval_t, 1) << 0)
  91#define PMD_SECT_DIRTY          (_AT(pmdval_t, 1) << 55)
  92#define PMD_SECT_SPLITTING      (_AT(pmdval_t, 1) << 56)
  93#define PMD_SECT_NONE           (_AT(pmdval_t, 1) << 57)
  94
  95/*
  96 * To be used in assembly code with the upper page attributes.
  97 */
  98#define L_PTE_XN_HIGH           (1 << (54 - 32))
  99#define L_PTE_DIRTY_HIGH        (1 << (55 - 32))
 100
 101/*
 102 * AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
 103 */
 104#define L_PTE_MT_UNCACHED       (_AT(pteval_t, 0) << 2) /* strongly ordered */
 105#define L_PTE_MT_BUFFERABLE     (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
 106#define L_PTE_MT_WRITETHROUGH   (_AT(pteval_t, 2) << 2) /* normal inner write-through */
 107#define L_PTE_MT_WRITEBACK      (_AT(pteval_t, 3) << 2) /* normal inner write-back */
 108#define L_PTE_MT_WRITEALLOC     (_AT(pteval_t, 7) << 2) /* normal inner write-alloc */
 109#define L_PTE_MT_DEV_SHARED     (_AT(pteval_t, 4) << 2) /* device */
 110#define L_PTE_MT_DEV_NONSHARED  (_AT(pteval_t, 4) << 2) /* device */
 111#define L_PTE_MT_DEV_WC         (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
 112#define L_PTE_MT_DEV_CACHED     (_AT(pteval_t, 3) << 2) /* normal inner write-back */
 113#define L_PTE_MT_MASK           (_AT(pteval_t, 7) << 2)
 114
 115/*
 116 * Software PGD flags.
 117 */
 118#define L_PGD_SWAPPER           (_AT(pgdval_t, 1) << 55)        /* swapper_pg_dir entry */
 119
 120/*
 121 * 2nd stage PTE definitions for LPAE.
 122 */
 123#define L_PTE_S2_MT_UNCACHED     (_AT(pteval_t, 0x5) << 2) /* MemAttr[3:0] */
 124#define L_PTE_S2_MT_WRITETHROUGH (_AT(pteval_t, 0xa) << 2) /* MemAttr[3:0] */
 125#define L_PTE_S2_MT_WRITEBACK    (_AT(pteval_t, 0xf) << 2) /* MemAttr[3:0] */
 126#define L_PTE_S2_RDONLY          (_AT(pteval_t, 1) << 6)   /* HAP[1]   */
 127#define L_PTE_S2_RDWR            (_AT(pteval_t, 3) << 6)   /* HAP[2:1] */
 128
 129/*
 130 * Hyp-mode PL2 PTE definitions for LPAE.
 131 */
 132#define L_PTE_HYP               L_PTE_USER
 133
 134#ifndef __ASSEMBLY__
 135
 136#define pud_none(pud)           (!pud_val(pud))
 137#define pud_bad(pud)            (!(pud_val(pud) & 2))
 138#define pud_present(pud)        (pud_val(pud))
 139#define pmd_table(pmd)          ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 140                                                 PMD_TYPE_TABLE)
 141#define pmd_sect(pmd)           ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 142                                                 PMD_TYPE_SECT)
 143
 144#define pud_clear(pudp)                 \
 145        do {                            \
 146                *pudp = __pud(0);       \
 147                clean_pmd_entry(pudp);  \
 148        } while (0)
 149
 150#define set_pud(pudp, pud)              \
 151        do {                            \
 152                *pudp = pud;            \
 153                flush_pmd_entry(pudp);  \
 154        } while (0)
 155
 156static inline pmd_t *pud_page_vaddr(pud_t pud)
 157{
 158        return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
 159}
 160
 161/* Find an entry in the second-level page table.. */
 162#define pmd_index(addr)         (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 163static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 164{
 165        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
 166}
 167
 168#define pmd_bad(pmd)            (!(pmd_val(pmd) & 2))
 169
 170#define copy_pmd(pmdpd,pmdps)           \
 171        do {                            \
 172                *pmdpd = *pmdps;        \
 173                flush_pmd_entry(pmdpd); \
 174        } while (0)
 175
 176#define pmd_clear(pmdp)                 \
 177        do {                            \
 178                *pmdp = __pmd(0);       \
 179                clean_pmd_entry(pmdp);  \
 180        } while (0)
 181
 182/*
 183 * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
 184 * that are written to a page table but not for ptes created with mk_pte.
 185 *
 186 * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
 187 * hugetlb_cow, where it is compared with an entry in a page table.
 188 * This comparison test fails erroneously leading ultimately to a memory leak.
 189 *
 190 * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
 191 * present before running the comparison.
 192 */
 193#define __HAVE_ARCH_PTE_SAME
 194#define pte_same(pte_a,pte_b)   ((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG     \
 195                                        : pte_val(pte_a))                               \
 196                                == (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG   \
 197                                        : pte_val(pte_b)))
 198
 199#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))
 200
 201#define pte_huge(pte)           (pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
 202#define pte_mkhuge(pte)         (__pte(pte_val(pte) & ~PTE_TABLE_BIT))
 203
 204#define pmd_young(pmd)          (pmd_val(pmd) & PMD_SECT_AF)
 205
 206#define __HAVE_ARCH_PMD_WRITE
 207#define pmd_write(pmd)          (!(pmd_val(pmd) & PMD_SECT_RDONLY))
 208
 209#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 210#define pmd_trans_huge(pmd)     (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
 211#define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING)
 212#endif
 213
 214#define PMD_BIT_FUNC(fn,op) \
 215static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }
 216
 217PMD_BIT_FUNC(wrprotect, |= PMD_SECT_RDONLY);
 218PMD_BIT_FUNC(mkold,     &= ~PMD_SECT_AF);
 219PMD_BIT_FUNC(mksplitting, |= PMD_SECT_SPLITTING);
 220PMD_BIT_FUNC(mkwrite,   &= ~PMD_SECT_RDONLY);
 221PMD_BIT_FUNC(mkdirty,   |= PMD_SECT_DIRTY);
 222PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);
 223
 224#define pmd_mkhuge(pmd)         (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
 225
 226#define pmd_pfn(pmd)            (((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 227#define pfn_pmd(pfn,prot)       (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 228#define mk_pmd(page,prot)       pfn_pmd(page_to_pfn(page),prot)
 229
 230/* represent a notpresent pmd by zero, this is used by pmdp_invalidate */
 231#define pmd_mknotpresent(pmd)   (__pmd(0))
 232
 233static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 234{
 235        const pmdval_t mask = PMD_SECT_USER | PMD_SECT_XN | PMD_SECT_RDONLY |
 236                                PMD_SECT_VALID | PMD_SECT_NONE;
 237        pmd_val(pmd) = (pmd_val(pmd) & ~mask) | (pgprot_val(newprot) & mask);
 238        return pmd;
 239}
 240
 241static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 242                              pmd_t *pmdp, pmd_t pmd)
 243{
 244        BUG_ON(addr >= TASK_SIZE);
 245
 246        /* create a faulting entry if PROT_NONE protected */
 247        if (pmd_val(pmd) & PMD_SECT_NONE)
 248                pmd_val(pmd) &= ~PMD_SECT_VALID;
 249
 250        *pmdp = __pmd(pmd_val(pmd) | PMD_SECT_nG);
 251        flush_pmd_entry(pmdp);
 252}
 253
 254static inline int has_transparent_hugepage(void)
 255{
 256        return 1;
 257}
 258
 259#endif /* __ASSEMBLY__ */
 260
 261#endif /* _ASM_PGTABLE_3LEVEL_H */
 262