diff options
Diffstat (limited to 'src/bootloader')
| -rw-r--r-- | src/bootloader/cd.asm (renamed from src/bootloader/loader.asm) | 3 | ||||
| -rw-r--r-- | src/bootloader/grub.cfg | 7 | ||||
| -rw-r--r-- | src/bootloader/hdd1.asm | 118 | ||||
| -rw-r--r-- | src/bootloader/hdd2.asm | 388 | ||||
| -rw-r--r-- | src/bootloader/make_initrd.c | 53 |
5 files changed, 507 insertions, 62 deletions
diff --git a/src/bootloader/loader.asm b/src/bootloader/cd.asm index 28e4562..1e83a3a 100644 --- a/src/bootloader/loader.asm +++ b/src/bootloader/cd.asm @@ -6,7 +6,6 @@ mov [bootDriveID], dl jmp start -; The print function print: mov ah, 0x0E xor bh, bh @@ -441,4 +440,4 @@ lba_not_supported: boot db "BOOT" boot_len equ ($ - boot) kernelbin db "KERNEL.BIN", 0x3B, "1" -kernelbin_len equ ($ - kernelbin)
\ No newline at end of file +kernelbin_len equ ($ - kernelbin) diff --git a/src/bootloader/grub.cfg b/src/bootloader/grub.cfg deleted file mode 100644 index cb265b1..0000000 --- a/src/bootloader/grub.cfg +++ /dev/null @@ -1,7 +0,0 @@ -set timeout=0 -set default=0 -menuentry "Melvix" { - multiboot /boot/melvix.bin - module /boot/melvix.initrd - boot -}
\ No newline at end of file diff --git a/src/bootloader/hdd1.asm b/src/bootloader/hdd1.asm new file mode 100644 index 0000000..c347625 --- /dev/null +++ b/src/bootloader/hdd1.asm @@ -0,0 +1,118 @@ +BITS 16 +ORG 0x7C00 + +%define INODE_ADDRESS 0xF000 +%define INODE_NBLOCKS 20 +%define INODE_DBP0 24 + +; Save the boot drive id +mov [bootDriveID], dl + +jmp start + +print: + mov ah, 0x0E + xor bh, bh + .print_L: + lodsb + test al, al + jz .print_end + int 0x10 + jmp .print_L + .print_end: + ret + +bootDriveID: db 0 + +dapack: + dapack_size: db 0x10 + dapack_null: db 0x00 + dapack_blkcount: dw 0x0001 + dapack_boffset: dw 0x8000 + dapack_bsegment: dw 0x0000 + dapack_start: dd 0x00000000 + dapack_upper_lba_bits: dd 0x00000000 + +readsector: + mov dword [dapack_start], eax + mov ah, 0x42 + mov dl, [bootDriveID] + xor bx, bx + mov ds, bx + mov si, dapack + int 0x13 + ret + +; 5K max +readwholefile: + mov bx, word [dapack_boffset] + push bx + mov bx, INODE_ADDRESS + mov word [dapack_boffset], bx + call readsector + pop bx + mov word [dapack_boffset], bx + + mov edx, [INODE_ADDRESS+INODE_NBLOCKS] + + xor ecx, ecx + .readwholefile_L: + lea bx, [INODE_ADDRESS + INODE_DBP0 + (ecx*4)] + mov eax, dword [bx] + + push dx + call readsector + pop dx + + add dword [dapack_boffset], 512 + + inc cx + cmp cx, dx + jl .readwholefile_L + ret + +welcome db "Melvix", 0x0A, 0x0D, 0x00 +nolba db "BIOS lacks support for LBA addressing.", 0x00 +signaturebad db "Bad disk signature.", 0x00 + +start: + mov ax, 0x0003 + int 0x10 + + mov si, welcome + call print + + mov ah, 0x41 + mov bx, 0x55AA + int 0x13 + jc lba_not_supported + cmp bx, 0xAA55 + jnz lba_not_supported + + mov eax, 1 + call readsector + + mov eax, [0x8000+0] + cmp eax, 0x34B59645 + jnz signature_BAD + mov eax, [0x8000+4] + cmp eax, 0x1083B99F + jnz signature_BAD + + mov eax, 2 + call readwholefile + + jmp 0x8000 + +lba_not_supported: + mov si, nolba + call print + jmp $ + +signature_BAD: + mov si, signaturebad + call print + jmp $ + +times 510-($-$$) db 0 +dw 0xAA55
\ No newline at end of file diff --git a/src/bootloader/hdd2.asm b/src/bootloader/hdd2.asm new file mode 100644 index 0000000..e289c39 --- /dev/null +++ b/src/bootloader/hdd2.asm @@ -0,0 +1,388 @@ +BITS 16 +ORG 0x8000 + +%define SECTOR_BUFFER 0x9000 +%define INODE_NBLOCKS 20 +%define INODE_DBP0 24 +%define INODE_SIBP 64 +%define INODE_DIBP 68 +%define INODE_TIBP 72 +%define INODE_QIBP 76 + +mov esp, 0xFFFF +jmp start + +checkA20: + ; Stolen from https://wiki.osdev.org/A20_Line + pushf + push ds + push es + push di + push si + cli + xor ax, ax + mov es, ax + not ax + mov ds, ax + mov di, 0x0500 + mov si, 0x0510 + mov al, byte [es:di] + push ax + mov al, byte [ds:si] + push ax + mov byte [es:di], 0x00 + mov byte [ds:si], 0xFF + cmp byte [es:di], 0xFF + pop ax + mov byte [ds:si], al + pop ax + mov byte [es:di], al + mov ax, 0 + jz checkA20_exit + mov ax, 1 + checkA20_exit: + pop si + pop di + pop es + pop ds + popf + ret + +last_maxlevel db 0 +getrecursive: + push edi + push esi + push ecx + + mov eax, edi + cmp al, byte [last_maxlevel] + jna .last_maxlevel_updated + mov byte [last_maxlevel], al + .last_maxlevel_updated: + + mov eax, esi + call 0x7c26 + + mov eax, dword [esp] + sub eax, 10 + + cmp byte [last_maxlevel], 1 + jna .check1 + mov ebx, 1 + shl ebx, 7 + sub eax, ebx + .check1: + cmp byte [last_maxlevel], 2 + jna .check2 + mov ebx, 1 + shl ebx, 14 + sub eax, ebx + .check2: + cmp byte [last_maxlevel], 3 + jna .check3 + mov ebx, 1 + shl ebx, 21 + sub eax, ebx + .check3: + mov ecx, dword [esp+8] + dec ecx + push ecx + shl ecx, 3 + sub ecx, dword [esp] + add esp, 4 + shr eax, cl + + mov eax, dword [SECTOR_BUFFER+(4*eax)] + + cmp dword [esp+8], 1 + jna .finish_recursion + mov edi, [esp+8] + dec edi + mov esi, eax + mov ecx, [esp] + call getrecursive + .finish_recursion: + mov byte [last_maxlevel], 0 + + pop ecx + pop esi + pop edi + ret + +get_block: + push ecx + push ebx + + xor ebx, ebx + inc ebx + shl ebx, 21 + add ebx, 9 + cmp ecx, ebx + jna .gtb1 + + mov edi, 4 + mov esi, dword [SECTOR_BUFFER+INODE_QIBP] + call getrecursive + jmp .get_block_end + + .gtb1: + xor ebx, ebx + inc ebx + shl ebx, 14 + add ebx, 9 + cmp ecx, ebx + jna .gtb2 + + mov edi, 3 + mov esi, dword [SECTOR_BUFFER+INODE_TIBP] + call getrecursive + jmp .get_block_end + + .gtb2: + xor ebx, ebx + inc ebx + shl ebx, 7 + add ebx, 9 + cmp ecx, ebx + jna .gtb3 + + mov edi, 2 + mov esi, dword [SECTOR_BUFFER+INODE_DIBP] + call getrecursive + jmp .get_block_end + + .gtb3: + cmp ecx, 9 + jna .gtb4 + + mov edi, 1 + mov esi, dword [SECTOR_BUFFER+INODE_SIBP] + call getrecursive + jmp .get_block_end + + .gtb4: + mov eax, SECTOR_BUFFER+INODE_DBP0 + mov eax, dword [eax+(4*ecx)] + + .get_block_end: + pop ebx + pop ecx + ret + +noa20 db "A20 could not be enabled.", 0 +loading db "Loading kernel...", 0x0A, 0x0D, 0x00 +booting db "Booting...", 0x0A, 0x0D, 0x00 +nomem db "BIOS does not support memory detection!", 0 +memno20 db "BIOS returns memory detection with 24 bytes. This has never been seen!", 0 + +start: + call checkA20 + test ax, ax + jnz A20_ENABLED + + in al, 0x92 + or al, 2 + out 0x92, al + + call checkA20 + test ax, ax + jnz A20_ENABLED + + mov si, noa20 + call 0x7c07 + jmp $ + +A20_ENABLED: + ; Inspired by https://wiki.osdev.org/Unreal_Mode + cli + push ds + lgdt [gdtinfo] + + mov eax, cr0 + or al, 1 + mov cr0, eax + + jmp $+2 + + mov bx, 0x08 + mov ds, bx + + and al, 0xFE + mov cr0, eax + pop ds + + mov si, loading + call 0x7c07 + + mov word [0x7c1a], SECTOR_BUFFER + + mov eax, 3 + call 0x7c26 + mov edx, dword [SECTOR_BUFFER + INODE_NBLOCKS] + + xor ecx, ecx +LOAD_KERNEL: + push edx + + mov eax, 3 + call 0x7c26 + call get_block + call 0x7c26 + + mov eax, ecx + shl eax, 9 + add eax, 0x200000 + + push ecx + xor ecx, ecx + .LOAD_KERNEL_L: + mov ebx, ecx + add ebx, SECTOR_BUFFER + mov ebx, dword [ebx] + + mov edx, ebx + mov ebx, eax + add ebx, ecx + mov dword [ebx], edx + + add ecx, 4 + cmp ecx, 2048 + jl .LOAD_KERNEL_L + pop ecx + + inc ecx + pop edx + cmp ecx, edx + jl LOAD_KERNEL + +mov si, booting +call 0x7c07 + +mov dl, [0x7c15] +mov byte [0x9000], dl + +mov di, 0xA000 +mov eax, 0xE820 +xor ebx, ebx +mov ecx, 24 +mov edx, 0x534D4150 +int 0x15 + +jc BIOS_NO_MEM +cmp eax, 0x534D4150 +jnz BIOS_NO_MEM +cmp cl, 20 +jnz BIOS_MEM_NO20 + +MEM_L: + test ebx, ebx + jz MEM_FINISHED + + mov ax, di + xor ch, ch + add ax, cx + mov di, ax + + mov eax, 0xE820 + mov ecx, 24 + int 0x15 + jmp MEM_L + +MEM_FINISHED: + mov eax, cr0 + or al, 1 + mov cr0, eax + + mov ax, 0x08 + mov ds, ax + mov es, ax + mov fs, ax + mov gs, ax + mov ss, ax + +; Infomation: https://wiki.osdev.org/ELF +mov ebx, 0x20002C +mov dl, byte [ebx] +push dx + +mov ebx, 0x20001C +mov ebx, dword [ebx] +push ebx + +xor dh, dh +PHT: + xor eax, eax + mov al, dh + shl eax, 5 + add eax, dword [esp] + add eax, 0x200000 + mov ebx, eax + + mov eax, dword [ebx] + cmp eax, 1 + jnz .PHT_ignore + + add ebx, 4 + mov eax, dword [ebx] + add eax, 0x200000 + push eax + + add ebx, 4 + mov eax, dword [ebx] + push eax + + add ebx, 8 + mov eax, dword [ebx] + push eax + + push dx + xor ecx, ecx + .MOVE_KERNEL_L: + mov ebx, [esp+10] + add ebx, ecx + mov ebx, dword [ebx] + + mov eax, ebx + mov ebx, dword [esp+6] + add ebx, ecx + mov dword [ebx], eax + + add ecx, 4 + cmp ecx, dword [esp+2] + jl .MOVE_KERNEL_L + pop dx + add esp, 12 + + .PHT_ignore: + inc dh + cmp dh, dl + jl PHT + +jmp (codedesc - gdt):protectedMode + +protectedMode: + BITS 32 + mov ebx, 0x100000 + mov eax, dword [ebx] + jmp eax + +BITS 16 +BIOS_NO_MEM: + mov si, nomem + call 0x7c07 + jmp $ +BIOS_MEM_NO20: + mov si, memno20 + call 0x7c07 + jmp $ + +gdtinfo: + dw gdt_end - gdt - 1 + dd gdt + gdt dd 0, 0 + flatdesc db 0xff, 0xff, 0, 0, 0, 10010010b, 11001111b, 0 + codedesc db 0xff, 0xff, 0, 0, 0, 10011010b, 11001111b, 0 + gdt_end: + +kernelbin db "KERNEL.BIN", 0x3B, "1" +kernelbin_len equ ($ - kernelbin) diff --git a/src/bootloader/make_initrd.c b/src/bootloader/make_initrd.c deleted file mode 100644 index 6c2e7a0..0000000 --- a/src/bootloader/make_initrd.c +++ /dev/null @@ -1,53 +0,0 @@ -#include <stdio.h> -#include <string.h> -#include <stdlib.h> - -struct initrd_header { - unsigned char magic; - char name[64]; - unsigned int offset; - unsigned int length; -}; - -int main(char argc, char **argv) { - int nheaders = (argc - 1) / 2; - struct initrd_header headers[64]; - printf("size of header: %d\n", (int) sizeof(struct initrd_header)); - unsigned int off = sizeof(struct initrd_header) * 64 + sizeof(int); - - for (int i = 0; i < nheaders; i++) { - printf("writing file %s->%s at 0x%x\n", argv[i * 2 + 1], argv[i * 2 + 2], off); - strcpy(headers[i].name, argv[i * 2 + 2]); - headers[i].name[strlen(argv[i * 2 + 2])] = '\0'; - headers[i].offset = off; - FILE *stream = fopen(argv[i * 2 + 1], "r"); - if (stream == 0) { - printf("Error: file not found: %s\n", argv[i * 2 + 1]); - return 1; - } - fseek(stream, 0, SEEK_END); - headers[i].length = ftell(stream); - off += headers[i].length; - fclose(stream); - headers[i].magic = 0xBF; - } - - FILE *wstream = fopen("./initrd.img", "w"); - unsigned char *data = (unsigned char *) malloc(off); - fwrite(&nheaders, sizeof(int), 1, wstream); - fwrite(headers, sizeof(struct initrd_header), 64, wstream); - - for (int i = 0; i < nheaders; i++) { - FILE *stream = fopen(argv[i * 2 + 1], "r"); - unsigned char *buf = (unsigned char *) malloc(headers[i].length); - fread(buf, 1, headers[i].length, stream); - fwrite(buf, 1, headers[i].length, wstream); - fclose(stream); - free(buf); - } - - fclose(wstream); - free(data); - - return 0; -} |