Fábio Coutada
62e8454f91
- make-uefi-iso.sh: UEFI ISO image builder - test_boot.S, test_boot.ld: test boot assembly and linker script - eim_config.toml: EIM (External Interface Module) configuration - edk2-ovmf RPM for UEFI firmware - GAP_ANALYSIS_PIKEOS_PARITY.md: PikeOS parity gap analysis
87 lines
1.7 KiB
ArmAsm
87 lines
1.7 KiB
ArmAsm
/*
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* Minimal Multiboot2 boot test — proves QEMU x86_64 can boot our kernel.
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*
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* SPDX-License-Identifier: MIT
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*/
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.section .multiboot, "ax"
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.align 8
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#define MULTIBOOT2_MAGIC 0x36d76289
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#define MULTIBOOT2_ARCH 0
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#define MULTIBOOT2_HDR_LEN 24
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mb2_header:
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.long MULTIBOOT2_MAGIC
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.long MULTIBOOT2_ARCH
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.long -(MULTIBOOT2_MAGIC + MULTIBOOT2_ARCH)
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.word MULTIBOOT2_HDR_LEN
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.word 0
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.section .text, "ax"
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.code32
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.global _start
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_start:
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/* Set up stack */
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movl $(_stack_top), %esp
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/* Save Multiboot2 info */
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pushl $0
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pushl %eax /* magic */
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pushl %ebx /* mboot info addr */
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/* Jump to 64-bit code */
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ljmp $0x08, $start64
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.section .text64, "ax"
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.code64
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start64:
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/* Set up 64-bit segments */
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movw $0x10, %ax
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movw %ax, %ds
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movw %ax, %es
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movw %ax, %ss
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xorw %ax, %ax
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movw %ax, %fs
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movw %ax, %gs
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/* Restore Multiboot2 info */
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popq %rdi /* magic */
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popq %rsi /* info addr */
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addq $8, %rsp /* skip padding */
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/* Write 'UOS' to VGA text buffer (0xb8000) to prove we're alive */
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movq $0x204F5355204F5355, %rax /* "UOS UOS" */
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movq %rax, (%rax)
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/* Write to serial port COM1 (0x3F8) */
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movw $0x3F8, %dx
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movb $'U', %al
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outb %al, (%dx)
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movb $'O', %al
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outb %al, (%dx)
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movb $'S', %al
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outb %al, (%dx)
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movb $' ', %al
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outb %al, (%dx)
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movb $'O', %al
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outb %al, (%dx)
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movb $'K', %al
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outb %al, (%dx)
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movb $0x0A, %al /* newline */
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outb %al, (%dx)
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movb $0x0D, %al /* carriage return */
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outb %al, (%dx)
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/* Halt */
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cli
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.Lhalt:
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hlt
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jmp .Lhalt
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.section .bss, "aw"
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.align 16
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_stack_bottom:
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.space 4096
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_stack_top:
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