Feat: Kernel up and running.
This commit is contained in:
AfonsoCMSousa
parent
9e4224793b
commit
3bd026ca7a
33
build.sh
33
build.sh
@ -13,32 +13,40 @@ BLUE='\033[0;34m'
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YELLOW='\033[1;33m'
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NC='\033[0m'
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# Prepare build environment
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echo -e "Preparing build environment...${NC}"
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echo -e "Creating Folders${NC}"
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mkdir -p bin obj boot include
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echo -e "${GREEN}✓ ${NC}Folders created.${NC}"
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# Step 1: Assemble Stage 1 bootloader (MBR - 512 bytes)
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echo -e "${BLUE}[1/6]${NC} Assembling Stage 1 bootloader (MBR)..."
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nasm -f bin boot.asm -o boot.bin
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nasm -f bin ./boot/boot.asm -o ./bin/boot.bin
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# Step 2: Assemble Stage 2 bootloader (extended loader)
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echo -e "${BLUE}[2/6]${NC} Assembling Stage 2 bootloader..."
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nasm -f bin elevator.asm -o elevator.bin
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nasm -f bin ./boot/elevator.asm -o ./bin/elevator.bin
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# Step 3: Assemble kernel entry point
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echo -e "${BLUE}[3/6]${NC} Assembling kernel entry..."
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nasm -f elf64 kernel.asm -o kernel.asm.o
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nasm -f elf64 kernel.asm -o ./obj/kernel.asm.o
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# Step 4: Compile kernel C code
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echo -e "${BLUE}[4/6]${NC} Compiling kernel..."
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gcc -ffreestanding -c kernel.c -o kernel.c.o -mcmodel=large -mno-red-zone -fno-pic -fno-pie -static -fno-stack-protector -nostdlib -mno-mmx -mno-sse -mno-sse2 -m64
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gcc -ffreestanding -c kernel.c -o ./obj/kernel.c.o -mcmodel=large -mno-red-zone -fno-pic -fno-pie -static -fno-stack-protector -nostdlib -mno-mmx -mno-sse -mno-sse2 -m64
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# Step 5: Link kernel
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echo -e "${BLUE}[5/6]${NC} Linking kernel..."
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ld -T linker.ld -o kernel.bin kernel.asm.o kernel.c.o --oformat binary
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ld -T linker.ld -o ./bin/kernel.bin ./obj/kernel.asm.o ./obj/kernel.c.o --oformat binary --nostdlib
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# Step 6: Create OS image
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echo -e "${BLUE}[6/6]${NC} Creating OS image..."
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cat boot.bin elevator.bin kernel.bin > os-image.bin
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cat ./bin/boot.bin ./bin/elevator.bin ./bin/kernel.bin > os.bin
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# Pad to floppy size (1.44MB)
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truncate -s 1440K os-image.bin
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# FIX: Uncomment the line below if you want to ensure the image is exactly 1.44MB
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#
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# truncate -s 1440K os-image.bin
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echo ""
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echo -e "${GREEN}✓ Build complete!${NC}"
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@ -55,17 +63,18 @@ echo ""
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echo "File Sizes:"
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printf "%-15s %10s\n" "File" "Size"
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printf "%-15s %10s\n" "----" "----"
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printf "%-15s %10d bytes\n" "boot.bin" $(stat -f%z boot.bin 2>/dev/null || stat -c%s stage1.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "elevator.bin" $(stat -f%z elevator.bin 2>/dev/null || stat -c%s stage2.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "kernel.bin" $(stat -f%z kernel.bin 2>/dev/null || stat -c%s kernel.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "os-image.bin" $(stat -f%z os-image.bin 2>/dev/null || stat -c%s os-image.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "boot.bin" $(stat -f%z ./bin/boot.bin 2>/dev/null || stat -c%s ./bin/boot.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "elevator.bin" $(stat -f%z ./bin/elevator.bin 2>/dev/null || stat -c%s ./bin/elevator.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "kernel.bin" $(stat -f%z ./bin/kernel.bin 2>/dev/null || stat -c%s ./bin/kernel.bin 2>/dev/null)
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printf "%-15s %10d bytes\n" "os.bin" $(stat -f%z os.bin 2>/dev/null || stat -c%s os.bin 2>/dev/null)
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echo ""
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echo -e "${YELLOW}Running QEMU...${NC}"
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echo "==================================="
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echo "Press Ctrl+C to exit QEMU"
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echo ""
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qemu-system-x86_64 -drive format=raw,file=os-image.bin -no-reboot -d cpu_reset
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qemu-system-x86_64 -drive format=raw,file=os.bin -no-reboot
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echo -e "${GREEN}Done!${NC}"
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179
elevator.asm
179
elevator.asm
@ -2,12 +2,12 @@
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; Stage 2 Bootloader - No size limit!
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; Job: Load kernel, set up GDT, switch to 64-bit mode, jump to kernel
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[org 0x7e00]
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[bits 16]
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KERNEL_OFFSET equ 0x10000 ; Load kernel at 64KB (safer than 0x1000)
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BOOT_DRIVE: db 0 ; Store boot drive number
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ERROR_CODE: db 0 ; Store error code from disk read
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stage2_start:
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; Print stage 2 message
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@ -36,12 +36,32 @@ stage2_start:
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call print_string
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pop ax
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push ax
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call print_hex_word ; Print the word we read
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; If it's 0x0000, kernel didn't load
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; Also check bytes 2-3
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mov ax, 0x1000
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mov es, ax
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mov bx, 2
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mov ax, [es:bx]
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xor bx, bx
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mov es, bx
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mov si, msg_space
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call print_string
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call print_hex_word
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; Check if first word is non-zero
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pop ax
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test ax, ax
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jz kernel_load_failed
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jnz .kernel_found
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; Kernel is zeros - try reading from different LBA offsets
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mov si, msg_searching
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call print_string
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jmp kernel_load_failed
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.kernel_found:
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mov si, msg_kernel_ok
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call print_string
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@ -67,6 +87,44 @@ load_kernel:
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push bx
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push cx
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push dx
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push si
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; Show what we're about to do
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mov si, msg_loading_kernel
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call print_string
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; Check if LBA is available
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mov ah, 0x41
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mov bx, 0x55AA
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mov dl, [BOOT_DRIVE]
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int 0x13
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jc .use_chs ; If carry set, LBA not supported
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; Use LBA mode
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mov si, msg_using_lba
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call print_string
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; Set up DAP (Disk Address Packet)
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mov word [dap_size], 0x10
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mov word [dap_sectors], 10
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mov word [dap_offset], 0x0000
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mov word [dap_segment], 0x1000
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mov dword [dap_lba_low], 6 ; LBA 6 = bytes 3072+ (sector 7 in CHS)
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mov dword [dap_lba_high], 0
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; Read using LBA
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mov ah, 0x42
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mov dl, [BOOT_DRIVE]
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mov si, dap
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int 0x13
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jc kernel_error
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jmp .read_done
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.use_chs:
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; Fall back to CHS mode
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mov si, msg_using_chs
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call print_string
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; Reset disk system first
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mov ah, 0x00
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@ -74,32 +132,51 @@ load_kernel:
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int 0x13
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; Set up ES:BX for the destination
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; KERNEL_OFFSET is 0x10000, so we need ES=0x1000, BX=0x0000
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mov ax, 0x1000
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mov es, ax
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xor bx, bx ; BX = 0, so ES:BX = 0x1000:0x0000 = 0x10000
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xor bx, bx
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; Now try loading kernel
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; Read using CHS
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mov ah, 0x02 ; Read function
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mov al, 10 ; Number of sectors
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mov ch, 0 ; Cylinder 0
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mov cl, 7 ; Start at sector 7
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mov cl, 7 ; Sector 7
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mov dh, 0 ; Head 0
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mov dl, [BOOT_DRIVE] ; Drive number
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int 0x13
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jc kernel_error
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.read_done:
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; Print success
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mov si, msg_sectors_read
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call print_string
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mov si, msg_newline
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call print_string
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; Restore ES to 0
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xor ax, ax
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mov es, ax
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pop si
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pop dx
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pop cx
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pop bx
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pop ax
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ret
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; Disk Address Packet for LBA
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align 4
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dap:
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dap_size: db 0x10
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dap_reserved: db 0
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dap_sectors: dw 0
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dap_offset: dw 0
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dap_segment: dw 0
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dap_lba_low: dd 0
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dap_lba_high: dd 0
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kernel_error:
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; Restore ES
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xor ax, ax
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@ -131,10 +208,73 @@ kernel_load_failed:
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xor ax, ax
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mov es, ax
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; Kernel is zeros at expected location
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; Let's try reading from different LBA sectors to find it
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mov si, msg_verify_failed
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call print_string
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; Try LBA 5
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mov si, msg_try_lba5
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call print_string
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mov word [dap_lba_low], 5
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call try_read_kernel
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; Try LBA 7
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mov si, msg_try_lba7
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call print_string
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mov word [dap_lba_low], 7
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call try_read_kernel
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; Try LBA 8
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mov si, msg_try_lba8
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call print_string
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mov word [dap_lba_low], 8
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call try_read_kernel
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jmp $
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try_read_kernel:
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push si
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; Read to 0x10000
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mov ax, 0x1000
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mov es, ax
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mov word [dap_segment], ax
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mov ah, 0x42
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mov dl, [BOOT_DRIVE]
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mov si, dap
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int 0x13
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; Check what we got
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xor bx, bx
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mov ax, [es:bx]
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xor cx, cx
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mov es, cx
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call print_hex_word
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mov si, msg_newline
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call print_string
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; If non-zero, we found it!
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test ax, ax
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jz .not_found
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mov si, msg_found
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call print_string
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; Jump directly to protected mode!
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cli
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lgdt [gdt_descriptor]
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mov eax, cr0
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or eax, 0x1
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mov cr0, eax
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jmp 0x08:protected_mode
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.not_found:
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pop si
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ret
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; ============================================================
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; PRINT STRING (16-bit)
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; ============================================================
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@ -195,11 +335,23 @@ print_hex_word:
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msg_stage2: db '[STAGE2] Extended bootloader loaded', 0x0D, 0x0A, 0
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msg_kernel_loaded: db '[STAGE2] Kernel loaded, switching to Protected Mode...', 0x0D, 0x0A, 0
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msg_kernel_error: db '[ERROR] Kernel load failed!', 0x0D, 0x0A, 0
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msg_kernel_check: db '[STAGE2] Verifying kernel load: Read word = 0x', 0
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msg_kernel_ok: db '[STAGE2] Kernel load verified.', 0x0D, 0x0A, 0
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msg_verify_failed: db '[ERROR] Kernel verification failed!', 0x0D, 0x0A, 0
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msg_error_code: db ' Error code: 0x', 0
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msg_drive: db ' Drive number: 0x', 0
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msg_error_code: db ' Error code: ', 0
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msg_drive: db ' Drive: ', 0
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msg_loading_kernel: db '[STAGE2] Loading kernel from disk...', 0x0D, 0x0A, 0
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msg_using_lba: db '[STAGE2] Using LBA mode for disk access', 0x0D, 0x0A, 0
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msg_using_chs: db '[STAGE2] Using CHS mode for disk access', 0x0D, 0x0A, 0
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msg_sectors_read: db '[STAGE2] Sectors read successfully', 0
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msg_newline: db 0x0D, 0x0A, 0
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msg_kernel_check: db '[STAGE2] Verifying kernel load: Read words: ', 0
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msg_space: db ' ', 0
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msg_searching: db '[STAGE2] Kernel not found, searching alternative sectors...', 0x0D, 0x0A, 0
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msg_kernel_ok: db '[STAGE2] Kernel verification successful!', 0x0D, 0x0A, 0
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msg_verify_failed: db '[STAGE2] Kernel verification failed.', 0x0D, 0x0A, 0
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msg_try_lba5: db '[STAGE2] Trying LBA 5...', 0x0D, 0x0A, 0
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msg_try_lba7: db '[STAGE2] Trying LBA 7...', 0x0D, 0x0A, 0
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msg_try_lba8: db '[STAGE2] Trying LBA 8...', 0x0D, 0x0A, 0
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msg_found: db '[STAGE2] Kernel found!', 0x0D, 0x0A, 0
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ERROR_CODE: db 0
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; ============================================================
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; GDT - Global Descriptor Table
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@ -488,3 +640,6 @@ print_64:
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lm_msg: db '[64-BIT] Long mode active...', 0
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before_kernel_msg: db '[64-BIT] Calling kernel...', 0
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kernel_return_msg: db '[KERNEL] Returned unexpectedly!', 0
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; Add pading to make the elevator 2560 bytes.
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times 2560 - ($ - $$) db 0
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2
kernel.c
2
kernel.c
@ -33,7 +33,7 @@ void kmain(void) {
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// Write messages
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write_string(10, 30, "SORA OS KERNEL", 0x0A); // Green
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write_string(12, 25, "64-bit kernel running!", 0x0F); // White
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write_string(14, 28, "System Initialized", 0x0E); // Yellow
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write_string(14, 28, "System Initialized", 0x0E); // Yellow
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// Infinite loop
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while (1) {
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