commit 455ceba13dc78a36180b01a89003565a9f8186da Author: Mika Date: Wed Sep 6 16:35:32 2023 +0200 init diff --git a/.DS_Store b/.DS_Store new file mode 100644 index 0000000..0a9ac0d Binary files /dev/null and b/.DS_Store differ diff --git a/.idea/.gitignore b/.idea/.gitignore new file mode 100644 index 0000000..13566b8 --- /dev/null +++ b/.idea/.gitignore @@ -0,0 +1,8 @@ +# Default ignored files +/shelf/ +/workspace.xml +# Editor-based HTTP Client requests +/httpRequests/ +# Datasource local storage ignored files +/dataSources/ +/dataSources.local.xml diff --git a/.idea/misc.xml b/.idea/misc.xml new file mode 100644 index 0000000..53624c9 --- /dev/null +++ b/.idea/misc.xml @@ -0,0 +1,18 @@ + + + + + + + + \ No newline at end of file diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..be94f12 --- /dev/null +++ b/Makefile @@ -0,0 +1,50 @@ +# Compiler and flags +ASM = i686-elf-as +CPP = i686-elf-g++ +LD = i686-elf-gcc +CFLAGS = -ffreestanding -O2 -Wall -Wextra -fno-exceptions -fno-rtti +LDFLAGS = -T linker.ld -ffreestanding -O2 -nostdlib -lgcc + +# Directories +SRC_DIR = src +BUILD_DIR = build + +# Source files +SRC_FILES := $(wildcard $(SRC_DIR)/*.cpp) $(wildcard $(SRC_DIR)/*/*.cpp) +ASM_FILES := $(wildcard $(SRC_DIR)/*.s) $(wildcard $(SRC_DIR)/*/*.s) + +# Object files +OBJ_FILES := $(patsubst $(SRC_DIR)/%.cpp,$(BUILD_DIR)/%.o,$(SRC_FILES)) +OBJ_FILES += $(patsubst $(SRC_DIR)/%.s,$(BUILD_DIR)/%.o,$(ASM_FILES)) + +# Output binary +OUTPUT = myos.bin + +# Build target +all: $(BUILD_DIR) $(OUTPUT) + +# Create the build directory if it doesn't exist +$(BUILD_DIR): + mkdir -p $(BUILD_DIR) + +# Compile C++ source files +$(BUILD_DIR)/%.o: $(SRC_DIR)/%.cpp + $(CPP) -c $< -o $@ $(CFLAGS) + +# Assemble assembly source files +$(BUILD_DIR)/%.o: $(SRC_DIR)/%.s + $(ASM) $< -o $@ + +# Link the object files to create the final binary +$(OUTPUT): $(OBJ_FILES) + $(LD) $(LDFLAGS) -o $@ $^ + +# Run QEMU after a successful build +run: all + qemu-system-i386 -kernel $(OUTPUT) + +# Clean build files +clean: + rm -rf $(BUILD_DIR) $(OUTPUT) + +.PHONY: all run clean diff --git a/build/Terminal.o b/build/Terminal.o new file mode 100644 index 0000000..4f8dfaf Binary files /dev/null and b/build/Terminal.o differ diff --git a/build/boot.o b/build/boot.o new file mode 100644 index 0000000..21c89c3 Binary files /dev/null and b/build/boot.o differ diff --git a/build/main.o b/build/main.o new file mode 100644 index 0000000..21dbbb7 Binary files /dev/null and b/build/main.o differ diff --git a/linker.ld b/linker.ld new file mode 100644 index 0000000..38ddd94 --- /dev/null +++ b/linker.ld @@ -0,0 +1,43 @@ +/* The bootloader will look at this image and start execution at the symbol + designated as the entry point. */ +ENTRY(_start) + +/* Tell where the various sections of the object files will be put in the final + kernel image. */ +SECTIONS +{ + /* Begin putting sections at 1 MiB, a conventional place for kernels to be + loaded at by the bootloader. */ + . = 1M; + + /* First put the multiboot header, as it is required to be put very early + early in the image or the bootloader won't recognize the file format. + Next we'll put the .text section. */ + .text BLOCK(4K) : ALIGN(4K) + { + *(.multiboot) + *(.text) + } + + /* Read-only data. */ + .rodata BLOCK(4K) : ALIGN(4K) + { + *(.rodata) + } + + /* Read-write data (initialized) */ + .data BLOCK(4K) : ALIGN(4K) + { + *(.data) + } + + /* Read-write data (uninitialized) and stack */ + .bss BLOCK(4K) : ALIGN(4K) + { + *(COMMON) + *(.bss) + } + + /* The compiler may produce other sections, by default it will put them in + a segment with the same name. Simply add stuff here as needed. */ +} diff --git a/src/IO/GDT.cpp b/src/IO/GDT.cpp new file mode 100644 index 0000000..8462934 --- /dev/null +++ b/src/IO/GDT.cpp @@ -0,0 +1,5 @@ +// +// Created by Mika on 06.09.23. +// + +#include "GDT.h" diff --git a/src/IO/GDT.h b/src/IO/GDT.h new file mode 100644 index 0000000..1ba1c68 --- /dev/null +++ b/src/IO/GDT.h @@ -0,0 +1,13 @@ +// +// Created by Mika on 06.09.23. +// + +#ifndef OS_GDT_H +#define OS_GDT_H + + +class GDT { +}; + + +#endif //OS_GDT_H diff --git a/src/IO/IO.h b/src/IO/IO.h new file mode 100644 index 0000000..4ff11ba --- /dev/null +++ b/src/IO/IO.h @@ -0,0 +1,32 @@ +// +// Created by Mika on 06.09.23. +// + +#ifndef OS_IO_H +#define OS_IO_H +#include + +class IO { +public: + static inline void outb(uint16_t port, uint8_t val) + { + asm volatile ( "outb %0, %1" : : "a"(val), "Nd"(port) :"memory"); + /* There's an outb %al, $imm8 encoding, for compile-time constant port numbers that fit in 8b. (N constraint). + * Wider immediate constants would be truncated at assemble-time (e.g. "i" constraint). + * The outb %al, %dx encoding is the only option for all other cases. + * %1 expands to %dx because port is a uint16_t. %w1 could be used if we had the port number a wider C type */ + } + + static inline uint8_t inb(uint16_t port) + { + uint8_t ret; + asm volatile ( "inb %1, %0" + : "=a"(ret) + : "Nd"(port) + : "memory"); + return ret; + } +}; + + +#endif //OS_IO_H diff --git a/src/IO/Interrupts.cpp b/src/IO/Interrupts.cpp new file mode 100644 index 0000000..716f1b1 --- /dev/null +++ b/src/IO/Interrupts.cpp @@ -0,0 +1,13 @@ +// +// Created by Mika on 06.09.23. +// + +#include "Interrupts.h" + +void Interrupts::disable() { + asm("cli"); +} + +void Interrupts::enable() { + asm("sti"); +} \ No newline at end of file diff --git a/src/IO/Interrupts.h b/src/IO/Interrupts.h new file mode 100644 index 0000000..5fda3b0 --- /dev/null +++ b/src/IO/Interrupts.h @@ -0,0 +1,16 @@ +// +// Created by Mika on 06.09.23. +// + +#ifndef OS_INTERRUPTS_H +#define OS_INTERRUPTS_H + + +class Interrupts { +public: + void disable(); + void enable(); +}; + + +#endif //OS_INTERRUPTS_H diff --git a/src/Terminal.cpp b/src/Terminal.cpp new file mode 100644 index 0000000..5e90424 --- /dev/null +++ b/src/Terminal.cpp @@ -0,0 +1,53 @@ +// +// Created by Mika on 06.09.23. +// + +#include "Terminal.h" + +void Terminal::init() { + terminal_row = 0; + terminal_column = 0; + terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK); + terminal_buffer = (uint16_t*) 0xB8000; + for(size_t y = 0; y < VGA_HEIGHT; y++) { + for(size_t x = 0; x < VGA_HEIGHT; x++) { + const size_t index = y * VGA_WIDTH + x; + terminal_buffer[index] = vga_entry(' ', terminal_color); + } + } +} + +void Terminal::setColor(uint8_t color) { + terminal_color = color; +} + +void Terminal::putEntryAt(char c, uint8_t color, size_t x, size_t y) { + const size_t index = y * VGA_WIDTH + x; + terminal_buffer[index] = vga_entry(c, color); +} + +void Terminal::putChar(char c) { + if(c == '\n') { + if(++terminal_row == VGA_HEIGHT) + terminal_row = 0; + terminal_column = 0; + return; + } + + Terminal::putEntryAt(c, terminal_color, terminal_column, terminal_row); + if(++terminal_column == VGA_WIDTH) { + terminal_column = 0; + + if(++terminal_row == VGA_HEIGHT) + terminal_row = 0; + } +} + +void Terminal::write(const char* data, size_t size) { + for(size_t i = 0; i < size; i++) + Terminal::putChar(data[i]); +} + +void Terminal::writeString(const char* data) { + Terminal::write(data, utils.strlen(data)); +} \ No newline at end of file diff --git a/src/Terminal.h b/src/Terminal.h new file mode 100644 index 0000000..cb406af --- /dev/null +++ b/src/Terminal.h @@ -0,0 +1,65 @@ +// +// Created by Mika on 06.09.23. +// + +#ifndef OS_TERMINAL_H +#define OS_TERMINAL_H +#include "Utils.h" + +class Terminal { +public: + void init(); + void putEntryAt(char c, uint8_t color, size_t x, size_t y); + void putChar(char c); + void setColor(uint8_t color); + void write(const char *data, size_t size); + void writeString(const char *data); + + enum vga_color { + VGA_COLOR_BLACK = 0, + VGA_COLOR_BLUE = 1, + VGA_COLOR_GREEN = 2, + VGA_COLOR_CYAN = 3, + VGA_COLOR_RED = 4, + VGA_COLOR_MAGENTA = 5, + VGA_COLOR_BROWN = 6, + VGA_COLOR_LIGHT_GREY = 7, + VGA_COLOR_DARK_GREY = 8, + VGA_COLOR_LIGHT_BLUE = 9, + VGA_COLOR_LIGHT_GREEN = 10, + VGA_COLOR_LIGHT_CYAN = 11, + VGA_COLOR_LIGHT_RED = 12, + VGA_COLOR_LIGHT_MAGENTA = 13, + VGA_COLOR_LIGHT_BROWN = 14, + VGA_COLOR_WHITE = 15, + }; + + static void kerror(const char* str, Terminal* terminal) { + terminal->setColor(vga_entry_color(VGA_COLOR_RED, VGA_COLOR_BLACK)); + terminal->writeString("[ERROR] "); + terminal->writeString(str); + terminal->writeString("\n\n"); + terminal->setColor(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK)); + } + +private: + static const size_t VGA_WIDTH = 80; + static const size_t VGA_HEIGHT = 25; + + size_t terminal_row; + size_t terminal_column; + uint8_t terminal_color; + uint16_t* terminal_buffer; + static Utils utils; + + static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) { + return fg | bg << 4; + } + + static inline uint16_t vga_entry(unsigned char uc, uint8_t color) { + return (uint16_t) uc | (uint16_t) color << 8; + } +}; + + +#endif //OS_TERMINAL_H diff --git a/src/Utils.h b/src/Utils.h new file mode 100644 index 0000000..e8d00e5 --- /dev/null +++ b/src/Utils.h @@ -0,0 +1,23 @@ +// +// Created by Mika on 06.09.23. +// + +#ifndef OS_UTILS_H +#define OS_UTILS_H +#include +#include +#include "Terminal.h" + +class Utils { +public: + static size_t strlen(const char* str) { + size_t len = 0; + while(str[len]) + len++; + + return len; + } +}; + + +#endif //OS_UTILS_H diff --git a/src/boot.s b/src/boot.s new file mode 100644 index 0000000..c45ecae --- /dev/null +++ b/src/boot.s @@ -0,0 +1,109 @@ +/* Declare constants for the multiboot header. */ +.set ALIGN, 1<<0 /* align loaded modules on page boundaries */ +.set MEMINFO, 1<<1 /* provide memory map */ +.set FLAGS, ALIGN | MEMINFO /* this is the Multiboot 'flag' field */ +.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */ +.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */ + +/* +Declare a multiboot header that marks the program as a kernel. These are magic +values that are documented in the multiboot standard. The bootloader will +search for this signature in the first 8 KiB of the kernel file, aligned at a +32-bit boundary. The signature is in its own section so the header can be +forced to be within the first 8 KiB of the kernel file. +*/ +.section .multiboot +.align 4 +.long MAGIC +.long FLAGS +.long CHECKSUM + +/* +The multiboot standard does not define the value of the stack pointer register +(esp) and it is up to the kernel to provide a stack. This allocates room for a +small stack by creating a symbol at the bottom of it, then allocating 16384 +bytes for it, and finally creating a symbol at the top. The stack grows +downwards on x86. The stack is in its own section so it can be marked nobits, +which means the kernel file is smaller because it does not contain an +uninitialized stack. The stack on x86 must be 16-byte aligned according to the +System V ABI standard and de-facto extensions. The compiler will assume the +stack is properly aligned and failure to align the stack will result in +undefined behavior. +*/ +.section .bss +.align 16 +stack_bottom: +.skip 16384 # 16 KiB +stack_top: + +/* +The linker script specifies _start as the entry point to the kernel and the +bootloader will jump to this position once the kernel has been loaded. It +doesn't make sense to return from this function as the bootloader is gone. +*/ +.section .text +.global _start +.type _start, @function +_start: + /* + The bootloader has loaded us into 32-bit protected mode on a x86 + machine. Interrupts are disabled. Paging is disabled. The processor + state is as defined in the multiboot standard. The kernel has full + control of the CPU. The kernel can only make use of hardware features + and any code it provides as part of itself. There's no printf + function, unless the kernel provides its own header and a + printf implementation. There are no security restrictions, no + safeguards, no debugging mechanisms, only what the kernel provides + itself. It has absolute and complete power over the + machine. + */ + + /* + To set up a stack, we set the esp register to point to the top of the + stack (as it grows downwards on x86 systems). This is necessarily done + in assembly as languages such as C cannot function without a stack. + */ + mov $stack_top, %esp + + /* + This is a good place to initialize crucial processor state before the + high-level kernel is entered. It's best to minimize the early + environment where crucial features are offline. Note that the + processor is not fully initialized yet: Features such as floating + point instructions and instruction set extensions are not initialized + yet. The GDT should be loaded here. Paging should be enabled here. + C++ features such as global constructors and exceptions will require + runtime support to work as well. + */ + + /* + Enter the high-level kernel. The ABI requires the stack is 16-byte + aligned at the time of the call instruction (which afterwards pushes + the return pointer of size 4 bytes). The stack was originally 16-byte + aligned above and we've pushed a multiple of 16 bytes to the + stack since (pushed 0 bytes so far), so the alignment has thus been + preserved and the call is well defined. + */ + call c_kernel_main + + /* + If the system has nothing more to do, put the computer into an + infinite loop. To do that: + 1) Disable interrupts with cli (clear interrupt enable in eflags). + They are already disabled by the bootloader, so this is not needed. + Mind that you might later enable interrupts and return from + kernel_main (which is sort of nonsensical to do). + 2) Wait for the next interrupt to arrive with hlt (halt instruction). + Since they are disabled, this will lock up the computer. + 3) Jump to the hlt instruction if it ever wakes up due to a + non-maskable interrupt occurring or due to system management mode. + */ + cli +1: hlt + jmp 1b + +/* +Set the size of the _start symbol to the current location '.' minus its start. +This is useful when debugging or when you implement call tracing. +*/ +.size _start, . - _start diff --git a/src/main.cpp b/src/main.cpp new file mode 100644 index 0000000..bcf8db5 --- /dev/null +++ b/src/main.cpp @@ -0,0 +1,15 @@ +#include "Terminal.h" + +void kernel_main() { + Terminal terminal{}; + + terminal.init(); + terminal.writeString("Hallo Jana\n"); + Terminal::kerror("Testing kerror", &terminal); + terminal.writeString("Hallo Arad\n"); +} + +extern "C" [[noreturn]] void c_kernel_main() { + kernel_main(); + while(true) {} +} \ No newline at end of file