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donjuanplatinumdonjuanplatinum
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add head_64.S and main function (#4)
1 parent 0aad394 commit 337f91b

4 files changed

Lines changed: 207 additions & 36 deletions

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‎.github/workflows/rust-test.yml‎

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@@ -11,6 +11,8 @@ on:
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- "**.ps1"
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- "**.yml"
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- "**.toml"
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- "**.S"
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- "**.ld"
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- "!**.md"
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pull_request:
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types: [opened, synchronize]
@@ -21,6 +23,8 @@ on:
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- "**.ps1"
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- "**.yml"
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- "**.toml"
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- "**.S"
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- "**.ld"
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- "!**.md"
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env:

‎crates/rkos-arch/src/x86/head_64.S‎

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@@ -0,0 +1,154 @@
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/*
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Bootstrapping x86_64 kernel
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see also: https://wiki.osdev.org/Entering_Long_Mode
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*/
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/* prepare space for 4-level paging to entering long mode
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.bss: | PML4 | PML3 | PML2 | Kernel_Stack(.bss.stack)|
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| 4kb | 4kb | 4kb | 16kb |
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*/
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.section .bss
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.align 4096
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p4_table:
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.skip 4096
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p3_table:
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.skip 4096
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p2_table:
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.skip 4096
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/* Kernel Stack */
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.section .bss.stack
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.align 16
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stack_bottom:
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.skip 16384
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stack_top:
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/*
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64-bit Global Descriptor Table (GDT)
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see also: https://wiki.osdev.org/Global_Descriptor_Table
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*/
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/* because of .rodata is read only now,when adding more features,we should move it to .data */
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.section .rodata
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/* every items in gdt64 is 8 bytes */
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.align 8
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gdt64:
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/* the first item is null */
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.quad 0x0000000000000000
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/* the second item is 64-bit code segment
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Base 63:56 0x00000000
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G 55 0
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D/B 54 0
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L 53 1 (64-bit code segment)
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AVL 52 0
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Limit 51:48 0x0000
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P 47 1
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DPL 46:45 0x00
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S 44 1
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Type 43:40 0x10
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Base 39:16 0x000000
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Limit 15:0 0x0000
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*/
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.quad 0x0020980000000000
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gdt64_pointer:
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/* length of gdt64 minus 1 */
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.word 15
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/* pointer to gdt64 */
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.quad gdt64
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/*
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multiboot header
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see also: https://wiki.osdev.org/Multiboot_Specification
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*/
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.section .text.entry
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.align 4
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.global multiboot_header
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multiboot_header:
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/* 0x1badb002: magic number for multiboot protocol*/
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.long 0x1badb002
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/* 0x00010000: flags */
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.long 0x00010000
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/* checksum */
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.long -(0x1badb002 + 0x00010000)
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/* pointer to multiboot_header */
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.long multiboot_header
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.long stext
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.long edata
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.long ebss
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.long _start
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/*
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start of 32-bit code
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*/
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.global _start
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_start:
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.code32
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/* set stack pointer */
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mov esp, offset stack_top
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/*
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set up temporary page table
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map first 2MB of physical memory to virtual memory
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*/
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mov eax, offset p3_table
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or eax, 0b11 /* 0b11 means present and writable */
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mov dword ptr [p4_table], eax
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/* p3_table[0] -> p2_table */
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mov eax, offset p2_table
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or eax, 0b11
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mov dword ptr [p3_table], eax
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/* map first 2MB of physical memory to virtual memory as huge page */
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mov eax, 0x83 /* 0x80 (Huge) + 0x02 (Writable) + 0x01 (Present) */
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mov dword ptr [p2_table], eax
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/* into long mode */
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/* step 1: set CR3 to p4_table */
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mov eax, offset p4_table
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mov cr3, eax
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/* step 2: enable PAE in CR4 */
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mov eax, cr4
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or eax, 1 << 5
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mov cr4, eax
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/* step 3: enable LME in EFER */
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mov ecx, 0xC0000080
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rdmsr
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or eax, 1 << 8
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wrmsr
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/* step 4: enable paging in CR0 */
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mov eax, cr0
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or eax, 1 << 31
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mov cr0, eax
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/* step 5: load gdt64 */
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lgdt [gdt64_pointer]
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/* jump to 64-bit code */
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push 8 /* push 64-bit code segment */
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mov eax, offset long_mode_start
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push eax /* push 64-bit code entry point */
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retf /* retf to long mode */
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.code64
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long_mode_start:
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/* first thing: set all data segment registers to 0 */
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mov ax, 0
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mov ss, ax
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mov ds, ax
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mov es, ax
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mov fs, ax
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mov gs, ax
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/* call _main */
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call _main
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/* if _main returns, loop forever */
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.loop64:
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hlt
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jmp .loop64

‎crates/rkos-arch/src/x86/link.ld‎

Lines changed: 21 additions & 7 deletions
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@@ -1,3 +1,7 @@
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/*
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linker script for x86_64 kernel
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see also: https://wiki.osdev.org/Linker_Scripts
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*/
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OUTPUT_ARCH(i386:x86-64)
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ENTRY(_start)
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@@ -8,32 +12,40 @@ KERNEL_BASE_ADDRESS = 0x100000;
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SECTIONS {
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. = KERNEL_BASE_ADDRESS;
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/* kernel code */
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/*
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.text: kernel code
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start at 0x100000
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*/
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.text : {
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stext = .;
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*(.text.entry)
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*(.text.entry)
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*(.text .text.*)
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. = ALIGN(4096);
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etext = .;
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}
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/* kernel rodata */
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/*
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.rodata: kernel rodata
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*/
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.rodata : {
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srodata = .;
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*(.rodata .rodata.*)
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. = ALIGN(4096);
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erodata = .;
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}
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28-
/* kernel data */
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/*
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.data: kernel data
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*/
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.data : {
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sdata = .;
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*(.data .data.*)
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. = ALIGN(4096);
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edata = .;
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}
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36-
/* kernel bss */
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/*
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.bss: kernel bss
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*/
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.bss : {
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sbss = .;
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*(.bss.stack) /* kernel stack */
@@ -43,7 +55,9 @@ SECTIONS {
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ebss = .;
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}
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46-
/* kernel end */
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/*
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kernel end
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*/
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. = ALIGN(4096);
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ekernel = .;
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}

‎crates/rkos/src/main.rs‎

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@@ -4,35 +4,34 @@
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use core::arch::global_asm;
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use core::panic::PanicInfo;
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7-
global_asm!(
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r#"
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.section .text.entry
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.align 4
11-
12-
.global multiboot_header
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multiboot_header:
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15-
.long 0x1badb002
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.long 0x00010000
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.long -(0x1badb002 + 0x00010000)
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.long multiboot_header
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.long stext
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.long edata
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.long ebss
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.long _start
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.global _start
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_start:
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.code32
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mov eax, 0x4f4f4f4f
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mov dword ptr [0xb8000], eax
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.loop:
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hlt
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jmp .loop
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"#
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);
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#[cfg(target_arch = "x86_64")]
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global_asm!(include_str!("../../rkos-arch/src/x86/head_64.S"));
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10+
#[unsafe(no_mangle)]
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pub extern "C" fn _main() {
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// VGA_BASE: 0xb8000
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let vga_buffer = 0xb8000 as *mut u8;
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let text = b"[OK] Barrensea rkos has conquered 64-bit Long Mode!!!";
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let color_byte = 0x0a;
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for (i, &byte) in text.iter().enumerate() {
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unsafe {
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*vga_buffer.add(i * 2) = byte;
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*vga_buffer.add(i * 2 + 1) = color_byte;
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}
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}
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unsafe extern "C" {
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fn stext();
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fn edata();
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fn ebss();
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}
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let _text_size = edata as *const () as usize - stext as *const () as usize;
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let _bss_size = ebss as *const () as usize - edata as *const () as usize;
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//loop {}
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}
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3736
#[panic_handler]
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fn panic(_info: &PanicInfo) -> ! {

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