initial commit

.gitignore

+/target

Cargo.lock

+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "kernel"
+version = "0.1.0"

Cargo.toml

+[package]
+name = "kernel"
+version = "0.1.0"
+edition = "2021"
+build = "build.rs"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

Makefile

+# target specific
+TARGET          = x86_64-unknown-none
+QEMU            = qemu-system-x86_64
+CONFIG          = x86_64
+EXTRA_RUSTFLAGS =
+
+KERNEL          = kernel
+KERNEL_ELF      = target/$(TARGET)/release/$(KERNEL)
+KERNEL_ELF_DEPS = $(filter-out %: ,$(file < $(KERNEL_ELF).d)) $(LD_SCRIPT_PATH)/$(LD_SCRIPT) Cargo.toml
+OS_ISO          = target/$(TARGET)/release/$(KERNEL).iso
+LD_SCRIPT_PATH  = $(shell pwd)/src/arch/x86_64
+LD_SCRIPT       = kernel.ld
+
+RUSTFLAGS   = $(EXTRA_RUSTFLAGS)                 \
+	-C link-arg=--library-path=$(LD_SCRIPT_PATH) \
+	-C link-arg=--script=$(LD_SCRIPT)
+
+CARGO_RUSTC = cargo rustc --release	--target=$(TARGET)
+
+.PHONY: run
+
+# compile kernel
+$(KERNEL_ELF): $(KERNEL_ELF_DEPS) Makefile
+	@echo "Compiling kernel ELF"
+	@RUSTFLAGS="$(RUSTFLAGS)" cargo rustc --target=$(TARGET)
+	cp target/$(TARGET)/debug/$(KERNEL) target/$(TARGET)/release/$(KERNEL)
+
+# generate grub iso
+$(OS_ISO): $(KERNEL_ELF) Makefile
+	@echo "Generate os iso"
+	@cp $(KERNEL_ELF) iso/boot/kernel
+	@grub-mkrescue /usr/lib/grub/i386-pc -o $@ iso &> /dev/null
+
+# just compile the kernel
+build: $(KERNEL_ELF) Makefile
+	@echo "$(KERNEL_ELF)"
+
+# compile and run silently
+run: $(OS_ISO) Makefile
+	@echo "Running kernel in QEMU"
+	@$(QEMU) $(OS_ISO) &> /dev/null
+
+# compile, run and start gdb
+debug: $(KERNEL_ELF) $(OS_ISO) Makefile
+	@echo "Debugging kernel in QEMU"
+	@$(QEMU) $(OS_ISO) -s &> /dev/null
+	@sleep 1
+	@gdb $(KERNEL_ELF) --eval-command "target remote :1234"

build.rs

+fn main() {}

iso/boot/.gitignore

+/kernel

iso/boot/grub/grub.cfg

+set timeout=0
+set default=0
+
+menuentry "kernel" {
+	multiboot2 /boot/kernel
+	boot
+}

src/arch/x86_64/boot.rs

+use core::arch::global_asm;
+
+global_asm!(include_str!("boot.s"));
+// global_asm!(include_str!("boot/check.asm"));
+// global_asm!(include_str!("boot/header.asm"));
+// global_asm!(include_str!("boot/long.asm"));
+// global_asm!(include_str!("boot/main.asm"));
+// global_asm!(include_str!("boot/memory.asm"));
+// global_asm!(include_str!("boot/setup.asm"));

src/arch/x86_64/boot.s

+// x86_64 multiboot2 kernel start
+
+/*
+    Multiboot header
+*/
+
+    .section .multiboot_header, "a"
+    .align 4
+    .global header_start
+header_start:
+    // magic number (multiboot2)
+    .int 0xE85250D6
+    // arch (protected mode i386)
+    .int 0
+    // header length
+    .int header_end - header_start
+    // checksum
+    .int 0x100000000 - (0xe85250d6 + 0 + header_end - header_start)
+
+    // end tag
+    .word 0
+    .word 0
+    .int 8
+header_end:
+
+/*
+    protected mode start
+*/
+
+    .section .inittext
+    .global start
+    .code32
+start:
+    // setup stack
+    mov esp, stack_top
+
+    // checks
+    call check_multiboot
+    call check_cpuid
+    call check_long_mode
+
+    // setups
+    call setup_page_tables
+    call enable_paging
+
+    // TODO: GDT before long mode
+    // lgdt [gdt64.pointer]
+    // jmp gdt64.code: start64
+    jmp start64
+
+    jmp halt
+
+error:
+    // print 'ERR: <err>'
+    mov dword ptr [0xb8000], 0x4f524f45
+    mov dword ptr [0xb8004], 0x4f3a4f52
+    mov dword ptr [0xb8008], 0x4f204f20
+    mov byte  ptr [0xb800a], al
+    jmp halt
+
+halt:
+    cli
+    // print 'ZZZ' as halting
+    mov word ptr [0xb8f00], 0x0f5a
+    mov word ptr [0xb8f02], 0x0f5a
+    mov word ptr [0xb8f04], 0x0f5a
+halt_repeat:
+    hlt
+    jmp halt_repeat
+
+/*
+    checks
+*/
+
+// check if booted from a multiboot
+// compliant bootloader
+check_multiboot:
+    cmp eax, 0x36d76289
+    jne .no_multiboot
+    ret
+.no_multiboot:
+    mov al, 'M'
+    jmp error
+
+// check for cpuid instruction availability
+// requirement for checking long mode support
+check_cpuid:
+    pushfd
+    pop eax
+    mov ecx, eax
+    xor eax, 1 << 21
+    push eax
+    popfd
+
+    pushfd
+    pop eax
+    push ecx
+    popfd
+
+    cmp eax, ecx
+    je .no_cpuid
+    ret
+.no_cpuid:
+    mov al, 'C'
+    jmp error
+
+// check for long mode availability
+// requires cpuid instruction availability
+check_long_mode:
+    mov eax, 0x80000000
+    cpuid
+    cmp eax, 0x80000001
+    jb .no_long_mode
+
+    mov eax, 0x80000001
+    cpuid
+    test edx, 1 << 29
+    jz .no_long_mode
+
+    ret
+.no_long_mode:
+    mov al, 'L'
+    jmp error
+
+/*
+    setups - page tables, paging, long mode
+*/
+
+setup_page_tables:
+    mov eax, p3_table
+    or  eax, 0b11 // present, writeable
+    mov [p4_table], eax
+
+    mov eax, p2_table
+    or  eax, 0b11 // present, writeable
+    mov [p3_table], eax
+
+    mov ecx, 0 // counter
+.loop:
+    mov eax, 0x200000 // 2MiB
+    mul ecx
+    or  eax, 0b10000011 // present, writeable, huge page
+    mov [p2_table + ecx * 8], eax
+
+    inc ecx // inc counter
+    cmp ecx, 512 // check if the whole table is mapped
+    jne .loop // if not: continue
+
+    ret
+
+enable_paging:
+    // pass page table location to the cpu
+    mov eax, p4_table
+    mov cr3, eax
+
+    // enable PAE
+    mov eax, cr4
+    or  eax, 1 << 5
+    mov cr4, eax
+
+    // enable long mode
+    mov ecx, 0xC0000080
+    rdmsr
+    or  eax, 1 << 8
+    wrmsr
+
+    hlt
+
+    // enable paging
+    mov eax, cr0
+    or  eax, 1 << 31
+    mov cr0, eax
+
+    ret
+
+    .section .text
+    .code64
+start64:
+    mov ax, 0
+    mov ss, ax
+    mov ds, ax
+    mov es, ax
+    mov fs, ax
+    mov gs, ax
+
+    // print 'OK'
+    mov dword ptr [0xb8000], 0x2f4b2f4f
+
+    call kernel_main
+    jmp halt
+
+/*
+    memory
+*/
+
+    .section .bss
+    .align 4096
+// page tables
+p4_table:
+    .skip 4096
+p3_table:
+    .skip 4096
+p2_table:
+    .skip 4096
+// 16 KiB stack
+stack_bottom:
+    .skip 4096 * 4
+stack_top:
+
+// TODO: global descriptor table
+/*.section .rodata
+gdt64:
+    .long 0 ; zero entry
+.code_segment: equ $ - gdt64
+    .long (1 << 43) | (1 << 44) | (1 << 47) | (1 << 53)
+.pointer:
+    .word $ - gdt64 - 1
+    .long gdt64*/

src/arch/x86_64/kernel.ld

+ENTRY(start)
+OUTPUT_FORMAT(elf64-x86-64)
+
+SECTIONS {
+    /* 2 << 20 */
+    . = 0x100000;
+
+    .boot : {
+        KEEP(*(.multiboot_header))
+        *(.inittext)
+    }
+
+    .text : {
+        *(.text)
+    }
+
+    .rodata : {
+        *(.rodata)
+    }
+
+    .data : {
+        *(.data)
+    }
+
+    .bss : {
+        *(.bss)
+    }
+}

src/main.rs

+#![no_std]
+#![no_main]
+
+#[cfg(target_arch = "x86_64")]
+#[path = "arch/x86_64/boot.rs"]
+mod arch_boot;
+
+use core::panic::PanicInfo;
+
+#[panic_handler]
+fn panic_handler(_: &PanicInfo) -> ! {
+    loop {}
+}
+
+#[no_mangle]
+fn kernel_main() {}