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  1. /*
  2.  * Copyright (c) 2007 Pavel Jancik, Michal Kebrt
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup arm32mm
  30.  * @{
  31.  */
  32. /** @file
  33.  *  @brief Paging related declarations.
  34.  */
  35.  
  36. #ifndef KERN_arm32_PAGE_H_
  37. #define KERN_arm32_PAGE_H_
  38.  
  39. #include <arch/mm/frame.h>
  40. #include <mm/mm.h>
  41. #include <arch/exception.h>
  42.  
  43. #define PAGE_WIDTH  FRAME_WIDTH
  44. #define PAGE_SIZE   FRAME_SIZE
  45.  
  46. #ifndef __ASM__
  47. #   define KA2PA(x) (((uintptr_t) (x)) - 0x80000000)
  48. #   define PA2KA(x) (((uintptr_t) (x)) + 0x80000000)
  49. #else
  50. #   define KA2PA(x) ((x) - 0x80000000)
  51. #   define PA2KA(x) ((x) + 0x80000000)
  52. #endif
  53.  
  54. #ifdef KERNEL
  55.  
  56. /* Number of entries in each level. */
  57. #define PTL0_ENTRIES_ARCH   (2 << 12)   /* 4096 */
  58. #define PTL1_ENTRIES_ARCH   0
  59. #define PTL2_ENTRIES_ARCH   0
  60. /* coarse page tables used (256 * 4 = 1KB per page) */
  61. #define PTL3_ENTRIES_ARCH   (2 << 8)    /* 256 */
  62.  
  63. /* Page table sizes for each level. */
  64. #define PTL0_SIZE_ARCH      FOUR_FRAMES
  65. #define PTL1_SIZE_ARCH      0
  66. #define PTL2_SIZE_ARCH      0
  67. #define PTL3_SIZE_ARCH      ONE_FRAME
  68.  
  69. /* Macros calculating indices into page tables for each level. */
  70. #define PTL0_INDEX_ARCH(vaddr)  (((vaddr) >> 20) & 0xfff)
  71. #define PTL1_INDEX_ARCH(vaddr)  0
  72. #define PTL2_INDEX_ARCH(vaddr)  0
  73. #define PTL3_INDEX_ARCH(vaddr)  (((vaddr) >> 12) & 0x0ff)
  74.  
  75. /* Get PTE address accessors for each level. */
  76. #define GET_PTL1_ADDRESS_ARCH(ptl0, i) \
  77.     ((pte_t *) ((((pte_level0_t *)(ptl0))[(i)]).coarse_table_addr << 10))
  78. #define GET_PTL2_ADDRESS_ARCH(ptl1, i) \
  79.     (ptl1)
  80. #define GET_PTL3_ADDRESS_ARCH(ptl2, i) \
  81.     (ptl2)
  82. #define GET_FRAME_ADDRESS_ARCH(ptl3, i) \
  83.     ((uintptr_t) ((((pte_level1_t *)(ptl3))[(i)]).frame_base_addr << 12))
  84.  
  85. /* Set PTE address accessors for each level. */
  86. #define SET_PTL0_ADDRESS_ARCH(ptl0) \
  87.     (set_ptl0_addr((pte_level0_t *) (ptl0)))
  88. #define SET_PTL1_ADDRESS_ARCH(ptl0, i, a) \
  89.     (((pte_level0_t *) (ptl0))[(i)].coarse_table_addr = (a) >> 10)
  90. #define SET_PTL2_ADDRESS_ARCH(ptl1, i, a)
  91. #define SET_PTL3_ADDRESS_ARCH(ptl2, i, a)
  92. #define SET_FRAME_ADDRESS_ARCH(ptl3, i, a) \
  93.     (((pte_level1_t *) (ptl3))[(i)].frame_base_addr = (a) >> 12)
  94.  
  95. /* Get PTE flags accessors for each level. */
  96. #define GET_PTL1_FLAGS_ARCH(ptl0, i) \
  97.     get_pt_level0_flags((pte_level0_t *) (ptl0), (index_t) (i))
  98. #define GET_PTL2_FLAGS_ARCH(ptl1, i) \
  99.     PAGE_PRESENT
  100. #define GET_PTL3_FLAGS_ARCH(ptl2, i) \
  101.     PAGE_PRESENT
  102. #define GET_FRAME_FLAGS_ARCH(ptl3, i) \
  103.     get_pt_level1_flags((pte_level1_t *) (ptl3), (index_t) (i))
  104.  
  105. /* Set PTE flags accessors for each level. */
  106. #define SET_PTL1_FLAGS_ARCH(ptl0, i, x) \
  107.     set_pt_level0_flags((pte_level0_t *) (ptl0), (index_t) (i), (x))
  108. #define SET_PTL2_FLAGS_ARCH(ptl1, i, x)
  109. #define SET_PTL3_FLAGS_ARCH(ptl2, i, x)
  110. #define SET_FRAME_FLAGS_ARCH(ptl3, i, x) \
  111.     set_pt_level1_flags((pte_level1_t *) (ptl3), (index_t) (i), (x))
  112.  
  113. /* Macros for querying the last-level PTE entries. */
  114. #define PTE_VALID_ARCH(pte) \
  115.     (*((uint32_t *) (pte)) != 0)
  116. #define PTE_PRESENT_ARCH(pte) \
  117.     (((pte_level0_t *) (pte))->descriptor_type != 0)
  118. #define PTE_GET_FRAME_ARCH(pte) \
  119.     (((pte_level1_t *) (pte))->frame_base_addr << FRAME_WIDTH)
  120. #define PTE_WRITABLE_ARCH(pte) \
  121.     (((pte_level1_t *) (pte))->access_permission_0 == \
  122.         PTE_AP_USER_RW_KERNEL_RW)
  123. #define PTE_EXECUTABLE_ARCH(pte) \
  124.     1
  125.  
  126. #ifndef __ASM__
  127.  
  128. /** Level 0 page table entry. */
  129. typedef struct {
  130.     /* 0b01 for coarse tables, see below for details */
  131.     unsigned descriptor_type : 2;
  132.     unsigned impl_specific : 3;
  133.     unsigned domain : 4;
  134.     unsigned should_be_zero : 1;
  135.  
  136.     /* Pointer to the coarse 2nd level page table (holding entries for small
  137.      * (4KB) or large (64KB) pages. ARM also supports fine 2nd level page
  138.      * tables that may hold even tiny pages (1KB) but they are bigger (4KB
  139.      * per table in comparison with 1KB per the coarse table)
  140.      */
  141.     unsigned coarse_table_addr : 22;
  142. } ATTRIBUTE_PACKED pte_level0_t;
  143.  
  144. /** Level 1 page table entry (small (4KB) pages used). */
  145. typedef struct {
  146.  
  147.     /* 0b10 for small pages */
  148.     unsigned descriptor_type : 2;
  149.     unsigned bufferable : 1;
  150.     unsigned cacheable : 1;
  151.  
  152.     /* access permissions for each of 4 subparts of a page
  153.      * (for each 1KB when small pages used */
  154.     unsigned access_permission_0 : 2;
  155.     unsigned access_permission_1 : 2;
  156.     unsigned access_permission_2 : 2;
  157.     unsigned access_permission_3 : 2;
  158.     unsigned frame_base_addr : 20;
  159. } ATTRIBUTE_PACKED pte_level1_t;
  160.  
  161.  
  162. /* Level 1 page tables access permissions */
  163.  
  164. /** User mode: no access, privileged mode: no access. */
  165. #define PTE_AP_USER_NO_KERNEL_NO    0
  166.  
  167. /** User mode: no access, privileged mode: read/write. */
  168. #define PTE_AP_USER_NO_KERNEL_RW    1
  169.  
  170. /** User mode: read only, privileged mode: read/write. */
  171. #define PTE_AP_USER_RO_KERNEL_RW    2
  172.  
  173. /** User mode: read/write, privileged mode: read/write. */
  174. #define PTE_AP_USER_RW_KERNEL_RW    3
  175.  
  176.  
  177. /* pte_level0_t and pte_level1_t descriptor_type flags */
  178.  
  179. /** pte_level0_t and pte_level1_t "not present" flag (used in descriptor_type). */
  180. #define PTE_DESCRIPTOR_NOT_PRESENT  0
  181.  
  182. /** pte_level0_t coarse page table flag (used in descriptor_type). */
  183. #define PTE_DESCRIPTOR_COARSE_TABLE 1
  184.  
  185. /** pte_level1_t small page table flag (used in descriptor type). */
  186. #define PTE_DESCRIPTOR_SMALL_PAGE   2
  187.  
  188.  
  189. /** Sets the address of level 0 page table.
  190.  *
  191.  * @param pt    Pointer to the page table to set.
  192.  */  
  193. static inline void set_ptl0_addr(pte_level0_t *pt)
  194. {
  195.     asm volatile (
  196.         "mcr p15, 0, %0, c2, c0, 0 \n"
  197.         :
  198.         : "r"(pt)
  199.     );
  200. }
  201.  
  202.  
  203. /** Returns level 0 page table entry flags.
  204.  *
  205.  *  @param pt     Level 0 page table.
  206.  *  @param i      Index of the entry to return.
  207.  */
  208. static inline int get_pt_level0_flags(pte_level0_t *pt, index_t i)
  209. {
  210.     pte_level0_t *p = &pt[i];
  211.     int np = (p->descriptor_type == PTE_DESCRIPTOR_NOT_PRESENT);
  212.  
  213.     return (np << PAGE_PRESENT_SHIFT) | (1 << PAGE_USER_SHIFT) |
  214.         (1 << PAGE_READ_SHIFT) | (1 << PAGE_WRITE_SHIFT) |
  215.         (1 << PAGE_EXEC_SHIFT) | (1 << PAGE_CACHEABLE_SHIFT);
  216. }
  217.  
  218. /** Returns level 1 page table entry flags.
  219.  *
  220.  *  @param pt     Level 1 page table.
  221.  *  @param i      Index of the entry to return.
  222.  */
  223. static inline int get_pt_level1_flags(pte_level1_t *pt, index_t i)
  224. {
  225.     pte_level1_t *p = &pt[i];
  226.  
  227.     int dt = p->descriptor_type;
  228.     int ap = p->access_permission_0;
  229.  
  230.     return ((dt == PTE_DESCRIPTOR_NOT_PRESENT) << PAGE_PRESENT_SHIFT) |
  231.         ((ap == PTE_AP_USER_RO_KERNEL_RW) << PAGE_READ_SHIFT) |
  232.         ((ap == PTE_AP_USER_RW_KERNEL_RW) << PAGE_READ_SHIFT) |
  233.         ((ap == PTE_AP_USER_RW_KERNEL_RW) << PAGE_WRITE_SHIFT) |
  234.         ((ap != PTE_AP_USER_NO_KERNEL_RW) << PAGE_USER_SHIFT) |
  235.         ((ap == PTE_AP_USER_NO_KERNEL_RW) << PAGE_READ_SHIFT) |
  236.         ((ap == PTE_AP_USER_NO_KERNEL_RW) << PAGE_WRITE_SHIFT) |
  237.         (1 << PAGE_EXEC_SHIFT) |
  238.         (p->bufferable << PAGE_CACHEABLE);
  239. }
  240.  
  241.  
  242. /** Sets flags of level 0 page table entry.
  243.  *
  244.  *  @param pt     level 0 page table
  245.  *  @param i      index of the entry to be changed
  246.  *  @param flags  new flags
  247.  */
  248. static inline void set_pt_level0_flags(pte_level0_t *pt, index_t i, int flags)
  249. {
  250.     pte_level0_t *p = &pt[i];
  251.  
  252.     if (flags & PAGE_NOT_PRESENT) {
  253.         p->descriptor_type = PTE_DESCRIPTOR_NOT_PRESENT;
  254.         /*
  255.          * Ensures that the entry will be recognized as valid when
  256.          * PTE_VALID_ARCH applied.
  257.          */
  258.         p->should_be_zero = 1;
  259.     } else {
  260.         p->descriptor_type = PTE_DESCRIPTOR_COARSE_TABLE;
  261.         p->should_be_zero = 0;
  262.     }
  263. }
  264.  
  265.  
  266. /** Sets flags of level 1 page table entry.
  267.  *
  268.  *  We use same access rights for the whole page. When page is not preset we
  269.  *  store 1 in acess_rigts_3 so that at least one bit is 1 (to mark correct
  270.  *  page entry, see #PAGE_VALID_ARCH).
  271.  *
  272.  *  @param pt     Level 1 page table.
  273.  *  @param i      Index of the entry to be changed.
  274.  *  @param flags  New flags.
  275.  */  
  276. static inline void set_pt_level1_flags(pte_level1_t *pt, index_t i, int flags)
  277. {
  278.     pte_level1_t *p = &pt[i];
  279.    
  280.     if (flags & PAGE_NOT_PRESENT) {
  281.         p->descriptor_type = PTE_DESCRIPTOR_NOT_PRESENT;
  282.         p->access_permission_3 = 1;
  283.     } else {
  284.         p->descriptor_type = PTE_DESCRIPTOR_SMALL_PAGE;
  285.         p->access_permission_3 = p->access_permission_0;
  286.     }
  287.  
  288.     p->cacheable = p->bufferable = (flags & PAGE_CACHEABLE) != 0;
  289.  
  290.     /* default access permission */
  291.     p->access_permission_0 = p->access_permission_1 =
  292.         p->access_permission_2 = p->access_permission_3 =
  293.         PTE_AP_USER_NO_KERNEL_RW;
  294.  
  295.     if (flags & PAGE_USER)  {
  296.         if (flags & PAGE_READ) {
  297.             p->access_permission_0 = p->access_permission_1 =
  298.                 p->access_permission_2 = p->access_permission_3 =
  299.                 PTE_AP_USER_RO_KERNEL_RW;
  300.         }
  301.         if (flags & PAGE_WRITE) {
  302.             p->access_permission_0 = p->access_permission_1 =
  303.                 p->access_permission_2 = p->access_permission_3 =
  304.                 PTE_AP_USER_RW_KERNEL_RW;
  305.         }
  306.     }
  307. }
  308.  
  309.  
  310. extern void page_arch_init(void);
  311.  
  312.  
  313. #endif /* __ASM__ */
  314.  
  315. #endif /* KERNEL */
  316.  
  317. #endif
  318.  
  319. /** @}
  320.  */
  321.