| 1 | /* ----------------------------------------------------------------------- |
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| 2 | * |
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| 3 | * Copyright 2003-2009 H. Peter Anvin - All Rights Reserved |
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| 4 | * Copyright 2009 Intel Corporation; author: H. Peter Anvin |
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| 5 | * |
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| 6 | * This program is free software; you can redistribute it and/or modify |
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| 7 | * it under the terms of the GNU General Public License as published by |
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| 8 | * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
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| 9 | * Boston MA 02110-1301, USA; either version 2 of the License, or |
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| 10 | * (at your option) any later version; incorporated herein by reference. |
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| 11 | * |
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| 12 | * ----------------------------------------------------------------------- */ |
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| 13 | |
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| 14 | /* |
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| 15 | * Simple stub to get us to the right point in the 32-bit code; |
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| 16 | * this module must be linked first |
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| 17 | */ |
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| 18 | |
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| 19 | .section ".init", "ax" |
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| 20 | .globl _start |
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| 21 | _start: |
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| 22 | /* Zero the bss */ |
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| 23 | cld |
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| 24 | movl $__bss_start, %edi |
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| 25 | movl $__bss_end, %ecx |
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| 26 | subl %edi, %ecx |
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| 27 | xorl %eax, %eax |
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| 28 | shrl $2, %ecx |
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| 29 | rep ; stosl |
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| 30 | |
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| 31 | /* Set up the protected-mode IDT and the interrupt jump buffers */ |
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| 32 | movl $idt, %edi |
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| 33 | movl $ijb, %eax |
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| 34 | movl $0xee000000, %ebx /* Interrupt gate */ |
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| 35 | movw %cs, %bx /* Target segment */ |
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| 36 | |
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| 37 | /* Make the IDT */ |
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| 38 | movl $256, %ecx |
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| 39 | 1: |
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| 40 | stosl |
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| 41 | stosl |
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| 42 | movl %ebx, -6(%edi) |
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| 43 | addl $8, %eax |
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| 44 | loop 1b |
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| 45 | |
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| 46 | /* |
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| 47 | * Each entry in the interrupt jump buffer contains the following |
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| 48 | * instructions: |
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| 49 | * |
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| 50 | * 60 pushal |
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| 51 | * b0xx movb $xx, %al # interrupt number |
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| 52 | * e9xxxxxxxx jmp handle_interrupt |
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| 53 | */ |
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| 54 | movl $0xe900b060, %eax |
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| 55 | movl $256, %ecx |
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| 56 | 1: |
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| 57 | movl %eax, (%edi) |
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| 58 | addl $(1 << 16), %eax |
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| 59 | movl $handle_interrupt-8, %edx |
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| 60 | subl %edi, %edx |
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| 61 | movl %edx, 4(%edi) |
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| 62 | addl $8, %edi |
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| 63 | loop 1b |
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| 64 | |
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| 65 | lidtl idt_ptr |
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| 66 | |
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| 67 | /* Save arguments, switch stacks */ |
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| 68 | movl %esp, %eax /* Pointer to arguments */ |
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| 69 | movl $__stack_end, %esp |
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| 70 | |
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| 71 | call setup |
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| 72 | jmp *(rm_args) /* First argument is return */ |
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| 73 | |
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| 74 | .section ".text","ax" |
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| 75 | .globl intcall |
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| 76 | .type intcall, @function |
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| 77 | intcall: |
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| 78 | jmp *(rm_args+1*4) /* Intcall is argument 1 */ |
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| 79 | .size intcall, .-intcall |
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| 80 | |
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| 81 | .type handle_interrupt, @function |
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| 82 | handle_interrupt: |
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| 83 | jmp *(rm_args+4*4) /* Interrupt pointer is argument 4 */ |
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| 84 | .size handle_interrupt, .-handle_interrupt |
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| 85 | |
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| 86 | .section ".rodata","a" |
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| 87 | idt_ptr: |
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| 88 | .word 8*256-1 |
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| 89 | .long idt |
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| 90 | .word 0 |
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| 91 | |
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| 92 | .section ".bss.large","aw" |
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| 93 | .balign 2048 |
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| 94 | idt: |
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| 95 | .space 8*256 |
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| 96 | ijb: |
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| 97 | .space 8*256 |
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| 98 | |
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| 99 | __stack: |
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| 100 | .space 65536 |
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| 101 | __stack_end: |
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