arch/arm64/include/asm/kernel-pgtable.h

   1 /*
   2  * Kernel page table mapping
   3  *
   4  * Copyright (C) 2015 ARM Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #ifndef __ASM_KERNEL_PGTABLE_H
  20 #define __ASM_KERNEL_PGTABLE_H
  21
  22
  23 /*
  24  * The linear mapping and the start of memory are both 2M aligned (per
  25  * the arm64 booting.txt requirements). Hence we can use section mapping
  26  * with 4K (section size = 2M) but not with 16K (section size = 32M) or
  27  * 64K (section size = 512M).
  28  */
  29 #ifdef CONFIG_ARM64_4K_PAGES
  30 #define ARM64_SWAPPER_USES_SECTION_MAPS 1
  31 #else
  32 #define ARM64_SWAPPER_USES_SECTION_MAPS 0
  33 #endif
  34
  35 /*
  36  * The idmap and swapper page tables need some space reserved in the kernel
  37  * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
  38  * map the kernel. With the 64K page configuration, swapper and idmap need to
  39  * map to pte level. The swapper also maps the FDT (see __create_page_tables
  40  * for more information). Note that the number of ID map translation levels
  41  * could be increased on the fly if system RAM is out of reach for the default
  42  * VA range, so pages required to map highest possible PA are reserved in all
  43  * cases.
  44  */
  45 #if ARM64_SWAPPER_USES_SECTION_MAPS
  46 #define SWAPPER_PGTABLE_LEVELS  (CONFIG_PGTABLE_LEVELS - 1)
  47 #define IDMAP_PGTABLE_LEVELS    (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT) - 1)
  48 #else
  49 #define SWAPPER_PGTABLE_LEVELS  (CONFIG_PGTABLE_LEVELS)
  50 #define IDMAP_PGTABLE_LEVELS    (ARM64_HW_PGTABLE_LEVELS(PHYS_MASK_SHIFT))
  51 #endif
  52
  53 #define SWAPPER_DIR_SIZE        (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
  54 #define IDMAP_DIR_SIZE          (IDMAP_PGTABLE_LEVELS * PAGE_SIZE)
  55
  56 /* Initial memory map size */
  57 #if ARM64_SWAPPER_USES_SECTION_MAPS
  58 #define SWAPPER_BLOCK_SHIFT     SECTION_SHIFT
  59 #define SWAPPER_BLOCK_SIZE      SECTION_SIZE
  60 #define SWAPPER_TABLE_SHIFT     PUD_SHIFT
  61 #else
  62 #define SWAPPER_BLOCK_SHIFT     PAGE_SHIFT
  63 #define SWAPPER_BLOCK_SIZE      PAGE_SIZE
  64 #define SWAPPER_TABLE_SHIFT     PMD_SHIFT
  65 #endif
  66
  67 /* The size of the initial kernel direct mapping */
  68 #define SWAPPER_INIT_MAP_SIZE   (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
  69
  70 /*
  71  * Initial memory map attributes.
  72  */
  73 #define SWAPPER_PTE_FLAGS       (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
  74 #define SWAPPER_PMD_FLAGS       (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
  75
  76 #if ARM64_SWAPPER_USES_SECTION_MAPS
  77 #define SWAPPER_MM_MMUFLAGS     (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
  78 #else
  79 #define SWAPPER_MM_MMUFLAGS     (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
  80 #endif
  81
  82
  83 #endif  /* __ASM_KERNEL_PGTABLE_H */