From 448ecd41edd95b86930b5ac7288f2ea9311d476c Mon Sep 17 00:00:00 2001 From: Xander Date: Wed, 28 Jun 2023 21:56:30 +0200 Subject: Reorganizing --- src/arch/x86_64/boot.asm | 163 ----------------------------------- src/arch/x86_64/grub.cfg | 7 -- src/arch/x86_64/linker.ld | 16 ---- src/arch/x86_64/long_mode_init.asm | 17 ---- src/arch/x86_64/multiboot_header.asm | 15 ---- 5 files changed, 218 deletions(-) delete mode 100644 src/arch/x86_64/boot.asm delete mode 100644 src/arch/x86_64/grub.cfg delete mode 100644 src/arch/x86_64/linker.ld delete mode 100644 src/arch/x86_64/long_mode_init.asm delete mode 100644 src/arch/x86_64/multiboot_header.asm (limited to 'src') diff --git a/src/arch/x86_64/boot.asm b/src/arch/x86_64/boot.asm deleted file mode 100644 index 2e334a8..0000000 --- a/src/arch/x86_64/boot.asm +++ /dev/null @@ -1,163 +0,0 @@ -global start -extern long_mode_start - -section .text -bits 32 -start: - mov esp, stack_top - - call check_multiboot - call check_cpuid - call check_long_mode - - call set_up_page_tables - call enable_paging - - ; load the 64-bit GDT - lgdt [gdt64.pointer] - - jmp gdt64.code:long_mode_start - - ; print `OK` to screen - mov dword [0xb8000], 0x2f4b2f4f - hlt - -check_multiboot: - cmp eax, 0x36d76289 - jne .no_multiboot - ret -.no_multiboot: - mov al, "0" - jmp error - -check_cpuid: - ; Check if CPUID is supported by attempting to flip the ID bit (bit 21) - ; in the FLAGS register. If we can flip it, CPUID is available. - - ; Copy FLAGS in to EAX via stack - pushfd - pop eax - - ; Copy to ECX as well for comparing later on - mov ecx, eax - - ; Flip the ID bit - xor eax, 1 << 21 - - ; Copy EAX to FLAGS via the stack - push eax - popfd - - ; Copy FLAGS back to EAX (with the flipped bit if CPUID is supported) - pushfd - pop eax - - ; Restore FLAGS from the old version stored in ECX (i.e. flipping the - ; ID bit back if it was ever flipped). - push ecx - popfd - - ; Compare EAX and ECX. If they are equal then that means the bit - ; wasn't flipped, and CPUID isn't supported. - cmp eax, ecx - je .no_cpuid - ret -.no_cpuid: - mov al, "1" - jmp error - -check_long_mode: - ; test if extended processor info in available - mov eax, 0x80000000 ; implicit argument for cpuid - cpuid ; get highest supported argument - cmp eax, 0x80000001 ; it needs to be at least 0x80000001 - jb .no_long_mode ; if it's less, the CPU is too old for long mode - - ; use extended info to test if long mode is available - mov eax, 0x80000001 ; argument for extended processor info - cpuid ; returns various feature bits in ecx and edx - test edx, 1 << 29 ; test if the LM-bit is set in the D-register - jz .no_long_mode ; If it's not set, there is no long mode - ret -.no_long_mode: - mov al, "2" - jmp error - -; Prints `ERR: ` and the given error code to screen and hangs. -; parameter: error code (in ascii) in al -error: - mov dword [0xb8000], 0x4f524f45 - mov dword [0xb8004], 0x4f3a4f52 - mov dword [0xb8008], 0x4f204f20 - mov byte [0xb800a], al - hlt - -set_up_page_tables: - ; map first P4 entry to P3 table - mov eax, p3_table - or eax, 0b11 ; present + writable - mov [p4_table], eax - - ; map first P3 entry to P2 table - mov eax, p2_table - or eax, 0b11 ; present + writable - mov [p3_table], eax - - ; map each P2 entry to a huge 2MiB page - mov ecx, 0 ; counter variable -.map_p2_table: - ; map ecx-th P2 entry to a huge page that starts at address 2MiB*ecx - mov eax, 0x200000 ; 2MiB - mul ecx ; start address of ecx-th page - or eax, 0b10000011 ; present + writable + huge - mov [p2_table + ecx * 8], eax ; map ecx-th entry - - inc ecx ; increase counter - cmp ecx, 512 ; if counter == 512, the whole P2 table is mapped - jne .map_p2_table ; else map the next entry - - ret - -enable_paging: - ; load P4 to cr3 register (cpu uses this to access the P4 table) - mov eax, p4_table - mov cr3, eax - - ; enable PAE-flag in cr4 (Physical Address Extension) - mov eax, cr4 - or eax, 1 << 5 - mov cr4, eax - - ; set the long mode bit in the EFER MSR (model specific register) - mov ecx, 0xC0000080 - rdmsr - or eax, 1 << 8 - wrmsr - - ; enable paging in the cr0 register - mov eax, cr0 - or eax, 1 << 31 - mov cr0, eax - - ret - -section .bss -align 4096 -p4_table: - resb 4096 -p3_table: - resb 4096 -p2_table: - resb 4096 -stack_bottom: - resb 64 -stack_top: - -section .rodata -gdt64: - dq 0 ; zero entry -.code: equ $ - gdt64 - dq (1<<43) | (1<<44) | (1<<47) | (1<<53) ; code segment -.pointer: - dw $ - gdt64 - 1 - dq gdt64 diff --git a/src/arch/x86_64/grub.cfg b/src/arch/x86_64/grub.cfg deleted file mode 100644 index 7c34c9c..0000000 --- a/src/arch/x86_64/grub.cfg +++ /dev/null @@ -1,7 +0,0 @@ -set timeout=0 -set default=0 - -menuentry "ats-os" { - multiboot2 /boot/kernel.bin - boot -} diff --git a/src/arch/x86_64/linker.ld b/src/arch/x86_64/linker.ld deleted file mode 100644 index 5d788f1..0000000 --- a/src/arch/x86_64/linker.ld +++ /dev/null @@ -1,16 +0,0 @@ -ENTRY(start) - -SECTIONS { - . = 1M; - - .boot : - { - /* ensure that the multiboot header is at the beginning */ - *(.multiboot_header) - } - - .text : - { - *(.text) - } -} diff --git a/src/arch/x86_64/long_mode_init.asm b/src/arch/x86_64/long_mode_init.asm deleted file mode 100644 index eab3788..0000000 --- a/src/arch/x86_64/long_mode_init.asm +++ /dev/null @@ -1,17 +0,0 @@ -global long_mode_start - -section .text -bits 64 -long_mode_start: - ; load 0 into all data segment registers - mov ax, 0 - mov ss, ax - mov ds, ax - mov es, ax - mov fs, ax - mov gs, ax - - ; print `OKAY` to screen - mov rax, 0x2f592f412f4b2f4f - mov qword [0xb8000], rax - hlt diff --git a/src/arch/x86_64/multiboot_header.asm b/src/arch/x86_64/multiboot_header.asm deleted file mode 100644 index 9a9289c..0000000 --- a/src/arch/x86_64/multiboot_header.asm +++ /dev/null @@ -1,15 +0,0 @@ -section .multiboot_header -header_start: - dd 0xe85250d6 ; magic number (multiboot 2) - dd 0 ; architecture 0 (protected mode i386) - dd header_end - header_start ; header length - ; checksum - dd 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start)) - - ; insert optional multiboot tags here - - ; required end tag - dw 0 ; type - dw 0 ; flags - dd 8 ; size -header_end: -- cgit v1.2.3