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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 arm32boot
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35.  
  36. #ifndef __MM_H__
  37. #define __MM_H__
  38.  
  39. #ifndef __ASM__
  40. #include "types.h"
  41. #endif
  42.  
  43.  
  44. #define FRAME_WIDTH                 12                  /* 4KB frames */
  45. #define FRAME_SIZE                  (1 << FRAME_WIDTH)
  46.  
  47. #define PAGE_WIDTH                  FRAME_WIDTH
  48. #define PAGE_SIZE                   FRAME_SIZE
  49.  
  50. #ifndef __ASM__
  51. #   define KA2PA(x)                 (((uintptr_t) (x)) - 0x80000000)
  52. #   define PA2KA(x)                 (((uintptr_t) (x)) + 0x80000000)
  53. #else
  54. #   define KA2PA(x)                 ((x) - 0x80000000)
  55. #   define PA2KA(x)                 ((x) + 0x80000000)
  56. #endif
  57.  
  58. /** Number of entries in PTL0 */
  59. #define PTL0_ENTRIES_ARCH               (1<<12)             /* 4096 */
  60.  
  61. /** Frames per 1MB section */
  62. #define FRAMES_PER_SECTION              ( ( 1 << 20 ) / FRAME_SIZE )
  63.  
  64. /** Converts adress to frame number */
  65. #define ADDR2PFN( addr )                ( ((uintptr_t)(addr))>>FRAME_WIDTH )
  66.  
  67. /** Descriptor type that signs "section" page table entry
  68.  * (one-level paging with 1MB sized pages)  */  
  69. #define PTE_DESCRIPTOR_SECTION              2
  70.  
  71. /** Access rights to page table: user-no access, kernel-read/write */
  72. #define PTE_AP_USER_NO_KERNEL_RW            1
  73.  
  74. #ifndef __ASM__
  75.  
  76.  
  77. /** Page table level 0 entry - "section" format (one-level paging, 1MB sized
  78.  * pages). Used only for booting the kernel. */
  79. typedef struct {
  80.     unsigned descriptor_type     : 2;
  81.     unsigned bufferable          : 1;
  82.     unsigned cacheable           : 1;
  83.     unsigned impl_specific       : 1;
  84.     unsigned domain              : 4;
  85.     unsigned should_be_zero_1    : 1;
  86.     unsigned access_permission   : 2;  
  87.     unsigned should_be_zero_2    : 8;
  88.     unsigned section_base_addr   : 12;
  89. } __attribute__ ((packed)) pte_level0_section_t;
  90.  
  91.  
  92. /** Page table that holds 1:1 mapping for booting the kernel. */
  93. extern pte_level0_section_t page_table[PTL0_ENTRIES_ARCH];
  94.  
  95.  
  96. /** Starts the MMU - initializes page table and enables paging. */
  97. void mmu_start(void);
  98.  
  99.  
  100. /** Enables paging. */
  101. static inline void enable_paging()
  102. {
  103.     /* c3 - each two bits controls access to the one of domains (16)
  104.      *      0b01 - behave as a client (user) of a domain
  105.      */
  106.     asm volatile (
  107.         // behave as a client of domains
  108.         "ldr r0, =0x55555555       \n"
  109.         "mcr p15, 0, r0, c3, c0, 0 \n"
  110.         // current settings
  111.         "mrc p15, 0, r0, c1, c0, 0 \n"
  112.         /* TODO: talk to Alf why needed
  113.         // mask to disable aligment checks; system & rom bit set to 0 (has no
  114.         // special effect)
  115.         "ldr r1, =0xfffffe8f       \n"
  116.         "and r0, r0, r1            \n"
  117.         */
  118.         // mask to enable paging
  119.         "ldr r1, =0x00000001       \n"
  120.         "orr r0, r0, r1            \n"
  121.         // store settings
  122.         "mcr p15, 0, r0, c1, c0, 0 \n"
  123.         :
  124.         :
  125.         : "r0", "r1"
  126.     );
  127. }
  128.  
  129.  
  130. /** Sets the address of level 0 page table.
  131.  * \param pt pointer to the page table to set
  132.  */  
  133. static inline void set_ptl0_address(pte_level0_section_t* pt)
  134. {
  135.     asm volatile ( "mcr p15, 0, %0, c2, c0, 0 \n"
  136.         :
  137.         : "r"(pt)
  138.     );
  139. }
  140.  
  141. #endif
  142.  
  143. #endif
  144.  
  145. /** @}
  146.  */
  147.  
  148.