| 1 | /*
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| 2 | * Copyright (C) 2005 Josef Cejka
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 |
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| 30 | #include <arch/boot/memmapasm.h>
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| 31 |
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| 32 | E820_RECORD_SIZE = MEMMAP_E820_RECORD_SIZE
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| 33 | E820_MAX_RECORDS = MEMMAP_E820_MAX_RECORDS
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| 34 | E820_SMAP = 0x534d4150
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| 35 |
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| 36 | .global memmap_arch_init
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| 37 | .global e820counter
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| 38 | .global e820table
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| 39 | .global e801memorysize
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| 40 |
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| 41 | .code16
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| 42 | .section K_TEXT_START_2
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| 43 |
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| 44 | memmap_arch_init:
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| 45 |
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| 46 | e820begin:
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| 47 | xorl %ebx,%ebx # during first call, ebx must be 0
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| 48 | movw %bx,%ds
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| 49 | movw %bx,%es
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| 50 | movw $e820table,%di
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| 51 | movb $E820_MAX_RECORDS,e820counter
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| 52 | e820loop:
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| 53 | movl $E820_SMAP,%edx # control sequence "SMAP"
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| 54 |
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| 55 | movl $0x0000e820,%eax # service
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| 56 | movl $E820_RECORD_SIZE,%ecx
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| 57 | int $0x15
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| 58 | jc e820err
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| 59 |
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| 60 | cmpl $E820_SMAP,%eax # verifying BIOS
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| 61 | jne e820err
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| 62 |
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| 63 | cmpl $E820_RECORD_SIZE,%ecx
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| 64 | jne e820err # bad record size - bug in bios
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| 65 |
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| 66 | movw %di,%ax # next record
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| 67 | addw $E820_RECORD_SIZE,%ax
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| 68 | movw %ax,%di
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| 69 |
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| 70 | decb e820counter # buffer is full
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| 71 | jz e820end
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| 72 |
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| 73 | cmpl $0,%ebx
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| 74 | jne e820loop
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| 75 |
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| 76 | e820end:
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| 77 | movb $E820_MAX_RECORDS,%al
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| 78 | subb e820counter,%al
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| 79 | movb %al,e820counter # store # of valid entries in e820counter
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| 80 |
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| 81 | jmp e801begin
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| 82 |
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| 83 | e820err:
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| 84 | movb $0,e820counter
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| 85 |
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| 86 | # method e801 - get size of memory
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| 87 |
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| 88 | e801begin:
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| 89 | xorw %dx,%dx
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| 90 | xorw %cx,%cx
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| 91 | xorw %bx,%bx
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| 92 | movw $0xe801,%ax
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| 93 | stc
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| 94 | int $0x15
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| 95 |
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| 96 | jc e801end
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| 97 |
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| 98 | # fix problem with some BIOSes which use ax:bx rather than cx:dx
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| 99 | testw %cx,%cx
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| 100 | jnz e801cxdx
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| 101 | testw %dx,%dx
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| 102 | jnz e801cxdx
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| 103 |
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| 104 | movw %ax,%cx
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| 105 | movw %bx,%dx
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| 106 |
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| 107 | e801cxdx:
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| 108 | andl $0xffff,%edx
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| 109 | shll $6,%edx
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| 110 | andl $0xffff,%ecx
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| 111 | addl %ecx,%edx
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| 112 | addl $0x0400,%edx # add lower 1 MB - it's not included by e801 method
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| 113 | movl %edx,e801memorysize
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| 114 | e801end:
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| 115 | ret
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| 116 |
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| 117 | #memory size in 1 kb chunks
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| 118 | e801memorysize:
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| 119 | .long 0
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| 120 |
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| 121 | e820counter:
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| 122 | .byte 0x0
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| 123 |
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| 124 | e820table:
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| 125 | .space (32*E820_RECORD_SIZE),0x0 # space for 32 records, each E820_RECORD_SIZE bytes long
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