Create bare bones kernel
The kernel supports writing to Graphics framebuffer in UEFI machines.
This commit is contained in:
parent
cbc4a19234
commit
5e3c17ee56
GPG Key ID:
B790DCEBE281403A
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@ -3,3 +3,6 @@ binutils.tar.gz
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cross/
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gcc-*/
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binutils-*/
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*.o
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build/
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.ccls-cache/
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57
Makefile
57
Makefile
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@ -1,12 +1,44 @@
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BINUTILS_VERSION=2.38
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GCC_VERSION=11.2.0
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PREFIX=${PWD}/cross
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CROSS_BIN=${PREFIX}/bin
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TARGET=i686-elf
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export PATH:=${CROSS_BIN}:$(PATH)
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BINUTILS_VERSION := 2.38
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GCC_VERSION := 11.2.0
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PREFIX := ${PWD}/cross
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CROSS_BIN := ${PREFIX}/bin
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BUILD_DIR := ./build
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TARGET := i686-elf
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FONTS := default8x16.o
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BUILD_DIR_ABS := $(abspath $(BUILD_DIR))
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FONT_OBJS := $(patsubst %.o,$(BUILD_DIR_ABS)/%.o, $(FONTS))
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CROSS_AS := ${TARGET}-as
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CROSS_CC := ${TARGET}-gcc
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CROSS_LD := ${TARGET}-ld
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CFLAGS := "-std=gnu99 -ffreestanding -O2 -Wall -Wextra -I$$PWD/kernel"
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LDFLAGS := "-ffreestanding -O2 -nostdlib -lgcc"
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export PATH := ${CROSS_BIN}:$(PATH)
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.PHONY: all
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all: $(BUILD_DIR)/kernel.bin $(BUILD_DIR)/$(FONTS)
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$(BUILD_DIR)/kernel.bin: $(BUILD_DIR) $(BUILD_DIR)/$(FONTS)
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@$(MAKE) -C kernel \
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BUILD_DIR=$(abspath $(BUILD_DIR)) \
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CROSS_AS=${CROSS_AS} \
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CROSS_CC=${CROSS_CC} \
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CROSS_LD=${CROSS_LD} \
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CFLAGS=${CFLAGS} \
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EXTRA_OBJS=${FONT_OBJS} \
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LDFLAGS=${LDFLAGS}
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$(BUILD_DIR):
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@mkdir -p $@
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$(BUILD_DIR)/$(FONTS):
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@$(MAKE) -C fonts BUILD_DIR=$(abspath $(BUILD_DIR)) OBJECTS=$(FONTS)
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.PHONY: crossdev
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crossdev: install-binutils install-gcc install-target-libgcc
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crossdev: install-binutils install-gcc install-target-libgcc clean-cross
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.PHONY: install-binutils
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install-binutils: build-binutils ${CROSS_BIN}
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@ -77,3 +109,14 @@ binutils.tar.gz:
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gcc.tar.gz:
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@curl -o $@ https://ftp.gnu.org/gnu/gcc/gcc-${GCC_VERSION}/gcc-${GCC_VERSION}.tar.gz
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.PHONY: clean-cross
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clean-cross:
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@rm -f gcc.tar.gz
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@rm -f binutils.tar.gz
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@rm -rf gcc-$(GCC_VERSION)
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@rm -rf binutils-$(BINUTILS_VERSION)
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.PHONY: clean
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clean:
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@rm -rf $(BUILD_DIR)
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@ -0,0 +1,26 @@
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OBJECTS_GZ := $(patsubst %.o, /usr/share/kbd/consolefonts/%.psfu.gz, $(OBJECTS))
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OBJECTS_PSF := $(patsubst %.o, $(BUILD_DIR)/%.psfu, $(OBJECTS))
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SYMS_PREFIX := consolefonts
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all: $(BUILD_DIR)/$(OBJECTS)
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$(BUILD_DIR)/%.o: $(OBJECTS_PSF)
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@objcopy \
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-O elf32-i386 \
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-B i386 \
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-I binary \
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$< $@
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@./gen_srd_file.sh \
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$<.srd \
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$< \
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$(SYMS_PREFIX)
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@objcopy \
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--redefine-syms $<.srd \
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$@
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@rm $<.srd
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$(BUILD_DIR)/%.psfu: $(BUILD_DIR)/%.psfu.gz
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@gzip -d $@
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$(BUILD_DIR)/%.psfu.gz: $(OBJECTS_GZ)
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@cp $< $(BUILD_DIR)
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@ -0,0 +1,19 @@
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#!/usr/bin/bash
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# Generates a symbol redefenition file for `ojbcopy`
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# The symbol redefenition filename
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sym_redefinition_filename=$1
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# The original filename from which the object was created
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origin_filename=$2
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# The symbol prefix
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prefix=$3
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path_prefix=$(readlink -f "${origin_filename}" | sed -E 's#/|\.#_#g')
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syms_prefix="_binary_${path_prefix}"
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echo "${syms_prefix}_start ${prefix}_binary__start" >> ${sym_redefinition_filename}
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echo "${syms_prefix}_end ${prefix}_binary__end" >> ${sym_redefinition_filename}
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echo "${syms_prefix}_size ${prefix}_binary__size" >> ${sym_redefinition_filename}
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@ -0,0 +1,29 @@
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SOURCES_S := boot.s
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OBJECTS_S := $(patsubst %.s, $(BUILD_DIR)/kernel/%.o, $(SOURCES_S))
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SOURCES_C := kernel.c
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HEADERS_C := multiboot.h psf.h
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OBJECTS_C := $(patsubst %.c, $(BUILD_DIR)/kernel/%.o, $(SOURCES_C))
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LINKER_LD := linker.ld
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.PHONY: all
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all: $(BUILD_DIR)/kernel.bin
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$(BUILD_DIR)/kernel.bin: $(OBJECTS_S) $(OBJECTS_C) $(LINKER_LD)
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$(CROSS_CC) \
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-T $(LINKER_LD) \
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$(LDFLAGS) \
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$(OBJECTS_C) \
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$(OBJECTS_S) \
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$(EXTRA_OBJS) \
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-o $@
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$(BUILD_DIR)/kernel/%.o: %.c $(SOURCES_C)
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@mkdir -p $(dir $@)
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@$(CROSS_CC) -c $< -o $@ $(CFLAGS)
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$(BUILD_DIR)/kernel/%.o: %.s $(SOURCES_S)
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@mkdir -p $(dir $@)
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@$(CROSS_AS) $< -o $@
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@ -0,0 +1,152 @@
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/* Declare constants for the multiboot header */
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.set ALIGN, 1<<0 /* align loaded modules on page boundaries */
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.set MEMINFO, 1<<1 /* provide memory map */
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.set VIDEO, 1<<2 /* enable graphics framebuffer */
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.set FLAGS, ALIGN | MEMINFO | VIDEO /* this is the Multiboot 'flag' field */
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.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
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.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */
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/*
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These are not used, but are needed for padding since we enable video and we
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are interested in the graphics field of the multiboot header.
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*/
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.set HEADER_ADDR, 0x0
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.set LOAD_ADDR, 0x0
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.set LOAD_END_ADDR, 0x0
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.set BSS_END_ADDR, 0x0
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.set ENTRY_ADDR, 0x0
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/* Graphics field of the multiboot header */
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.set MODE_TYPE, 0x0 /* Contains ‘0’ for linear graphics mode or ‘1’ for EGA-standard text mode */
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.set WIDTH, 0x0 /* Contains the number of the columns */
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.set HEIGHT, 0x0 /* Contains the number of the lines */
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.set DEPTH, 0x0 /* Contains the number of bits per pixel in a graphics mode, and zero in a text mode */
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/*
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Declare a multiboot header that marks the program as a kernel. These are magic
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values that are documented in the multiboot standard. The bootloader will
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search for this signature in the first 8 KiB of the kernel file, aligned at a
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32-bit boundary. The signature is in its own section so the header can be
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forced to be within the first 8 KiB of the kernel file.
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*/
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.section .multiboot
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.align 4
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.long MAGIC
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.long FLAGS
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.long CHECKSUM
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.long HEADER_ADDR
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.long LOAD_ADDR
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.long LOAD_END_ADDR
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.long BSS_END_ADDR
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.long ENTRY_ADDR
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.long MODE_TYPE
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.long WIDTH
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.long HEIGHT
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.long DEPTH
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/*
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The multiboot header layout is as follows:
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Offset Type Field Name Note
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0 u32 magic required
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4 u32 flags required
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8 u32 checksum required
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12 u32 header_addr if flags[16] is set
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16 u32 load_addr if flags[16] is set
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20 u32 load_end_addr if flags[16] is set
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24 u32 bss_end_addr if flags[16] is set
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28 u32 entry_addr if flags[16] is set
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32 u32 mode_type if flags[2] is set
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36 u32 width if flags[2] is set
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40 u32 height if flags[2] is set
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44 u32 depth if flags[2] is set
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*/
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/*
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The multiboot standard does not define the value of the stack pointer register
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(esp) and it is up to the kernel to provide a stack. This allocates room for a
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small stack by creating a symbol at the bottom of it, the allocating 16384
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bytes for it, and finally creating a symbol at the top. The stack grows
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downwards on x86. The stack is in its own section so it can be marked nobits,
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which means the kernel file is smaller because it does no contain an
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uninitialized stack. The stack on x86 must be 16-byte aligned according to the
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System V ABI standard and de-facto extensions. The compiler will assume the
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stack is properly aligned and failure to align the stack will result in
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undefined behavior.
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*/
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.section .bss
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.align 16
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stack_bottom:
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.skip 16384 # 16 KiB
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stack_top:
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/*
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The linker script specifies _start as the entry point to the kernel and the
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bootloader will jump to this position once the kernel has been loaded. It
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doesn't make sense to return from this function as the bootloader is gone.
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*/
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.section .text
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.global _start
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.type _start, @function
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_start:
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/*
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The bootloader has loaded us into 32-bit protected mode on a x86
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machine. Interrupts are disabled. Paging is disabled. The processor
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state is as defined in the multiboot standard. The kernel has full
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control of the CPU. The kernel can only make use of hardware features
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and any code it provides as part of itself. There's no printf
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function, unless the kernel provides its own <stdio.h> header and a
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printf implementation. There are no security restrictions, no
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safeguard, no debugging mechanisms, only what the kernel provides
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itself. It has absolute and comlete power over the machine.
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*/
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/*
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To set up a stack, we set the esp register to point to the top of the
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stack (as it grows downwards on x86 systems). This is necessarily done
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in assembly as languages such as C cannot function without a stack.
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*/
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mov $stack_top, %esp
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/*
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This is a good place to initialize crucial processor state before the
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high-level kernel is entered. It's best to minimize the early
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environment where crucial features are offline. Note that the
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processor is not fully initialized yet: Features such as floating
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point instructions and instruction set extensions are not initialized
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yet. The GDT should be loaded here. Paging should be enabled here.
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C++ features such as global constructors and exceptions will require
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runtime support to work as well.
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*/
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/*
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Enter the high-level kernel. The ABI requires the stack is 16-byte
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aligned at the time of the call instruction (which afterwards pushes
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the return pointer of size 4 bytes). The stack was originally 16-byte
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aligned above and we've pushed a multiple of 16 bytes to the stack
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since (pushed 0 bytes so far), so the alignment has thus been
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preserved and the call is well defined.
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*/
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pushl %ebx /* pass the Multiboot Info struct addr to kernel_main */
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call kernel_main
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/*
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If the system has nothing more to do, put the computer into an
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infinite loop. To do that:
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1) Disable interrupts with cli (clear interrupt enable in eflags).
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They are already disabled by the bootloader, so this is not needed.
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Mind that you might later enable interrupts and return from
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kernel_main (which is sort of nonsensical to do).
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2) Wait for the next interrupt to arrive with hlt (halt instruction).
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Since they are disabled, this will lock up the computer.
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3) Jump to the hlt instruction if it ever wakes up due to a
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non-maskable interrupt occurring or due to system management mode.
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*/
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cli
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1: hlt
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jmp 1b
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/*
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Set the size of the _start symbol to the current location '.' minus its start.
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This is useful when debugging or when you implement call tracing.
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*/
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.size _start, . - _start
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@ -0,0 +1,71 @@
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#include "multiboot.h"
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#include "psf.h"
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#include <stdint.h>
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#if defined (__linux__)
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#error "You are not using a cross-compiler, you will most certainly run into trouble"
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#endif
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#if !defined (__i386__)
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#error "The kernel needs to be compiled with a ix86-elf compiler"
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#endif
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/* graphics framebuffer */
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char *fb;
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/* number of bytes in each line */
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int scanline;
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/* extern the symbols in the psf object */
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extern char consolefonts_binary__start;
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extern char consolefonts_binary__end;
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multiboot_info_t *mbi;
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uint32_t console_y;
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uint32_t console_x;
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#define PIXEL uint32_t
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void putchar (uint16_t c, int32_t cx, int32_t cy, uint32_t fg, uint32_t bg)
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{
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psf_font_t *font = (psf_font_t *)&consolefonts_binary__start;
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uint32_t bytesperline = (font->width + 7) / 8;
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unsigned char *glyph = (unsigned char *)&consolefonts_binary__start + font->headersize +
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(c > 0 && c < font->numglyphs ? c : 0) * font->bytesperglyph;
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uint32_t offs = (cy * font->height * scanline) + (cx * (font->width + 1) * sizeof (PIXEL));
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uint32_t x, y, line, mask;
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for (y = 0; y < font->height; y++) {
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line = offs;
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mask = 1 << (font->width -1);
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for (x = 0; x < font->width; x++) {
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*((PIXEL *)(fb+line)) = *((uint32_t *)glyph) & mask ? fg : bg;
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mask >>= 1;
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line += sizeof (PIXEL);
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}
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glyph += bytesperline;
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offs += scanline;
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}
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}
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void kernel_main (uint64_t multiboot_struct_addr)
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{
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mbi = (multiboot_info_t *)multiboot_struct_addr;
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fb = (char *)mbi->framebuffer_addr;
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scanline = mbi->framebuffer_pitch;
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putchar ((uint16_t)'H', 0, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'e', 1, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'l', 2, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'l', 3, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'o', 4, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)' ', 5, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'W', 6, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'o', 7, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'r', 8, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'l', 9, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'d', 10, 0, 0xFFFFFFFF, 0);
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putchar ((uint16_t)'!', 11, 0, 0xFFFFFFFF, 0);
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}
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@ -0,0 +1,43 @@
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/* The bootloader will look at this image and start executing at the symbol
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* designated as the entry point. */
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ENTRY(_start)
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/* Tell where the various sections of the object files will be put in the final
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* kernel image. */
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SECTIONS
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{
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/* Begin putting sections at 1MiB, a conventional place for kernels to be
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* loaded at by the bootloader. */
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. = 1M;
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/* First put the multiboot header, as it is required to be put very early
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* in the image or the bootloader won't recongnize the file format. Next
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* we'll put the .text section. */
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.text BLOCK(4K) : ALIGN(4K)
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{
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*(.multiboot)
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*(.text)
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}
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/* Read-only data. */
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.rodata BLOCK(4K) : ALIGN(4K)
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{
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*(.rodata)
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}
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/* Read-write data (initialized). */
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.data BLOCK(4K) : ALIGN(4K)
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{
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*(.data)
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}
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/* Read-write data (uninitialized) and stack. */
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.bss BLOCK(4K) : ALIGN(4K)
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{
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*(COMMON)
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*(.bss)
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}
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/* The compiler may produce other sections, by default it will put them in
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* a segment with the same name. Simply add stuff here as needed. */
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}
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@ -0,0 +1,65 @@
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#include <stdint.h>
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#ifndef MULTIBOOT_HEADER
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#define MULTIBOOT_HEADER 1
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struct multiboot_info {
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uint32_t flags;
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/* present if flags[0] is set */
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uint32_t mem_lower;
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uint32_t mem_upper;
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/* present if flags[1] is set */
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uint32_t boot_device;
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/* present if flags[2] is set */
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uint32_t cmd_line;
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/* present if flags[3] is set */
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uint32_t mods_count;
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uint32_t mods_addr;
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/* present if flags[4] or flags[5] is set */
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uint32_t syms1;
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uint32_t syms2;
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uint32_t syms3;
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/* present if flags[6] is set */
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uint32_t mmap_length;
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uint32_t mmap_addr;
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/* present if flags[7] is set */
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||||
uint32_t drives_length;
|
||||
uint32_t drives_addr;
|
||||
|
||||
/* present if flags[8] is set */
|
||||
uint32_t config_table;
|
||||
|
||||
/* present if flags[9] is set */
|
||||
uint32_t boot_loader_name;
|
||||
|
||||
/* present if flags[10] is set */
|
||||
uint32_t apm_table;
|
||||
|
||||
/* present if flags[11] is set */
|
||||
uint32_t vbe_control_info;
|
||||
uint32_t vbe_mode_info;
|
||||
uint16_t vbe_mode;
|
||||
uint16_t vbe_interface_seg;
|
||||
uint16_t vbe_interface_off;
|
||||
uint16_t vbe_interface_len;
|
||||
|
||||
/* present if flags[12] is set */
|
||||
uint64_t framebuffer_addr;
|
||||
uint32_t framebuffer_pitch;
|
||||
uint32_t framebuffer_width;
|
||||
uint32_t framebuffer_height;
|
||||
uint8_t framebuffer_bpp;
|
||||
uint8_t framebuffer_type;
|
||||
uint32_t color_info1;
|
||||
uint16_t color_info2;
|
||||
}__attribute__((packed));
|
||||
typedef struct multiboot_info multiboot_info_t;
|
||||
|
||||
#endif
|
||||
|
|
@ -0,0 +1,20 @@
|
|||
#include <stdint.h>
|
||||
|
||||
#ifndef PSF_HEADER
|
||||
#define PSF_HEADER 1
|
||||
|
||||
#define PSF_FONT_MAGIC 0x864ab572
|
||||
|
||||
struct psf_font {
|
||||
uint32_t magic; /* magic bytes to identify psf */
|
||||
uint32_t version; /* zero */
|
||||
uint32_t headersize; /* offset of bitmaps in file, 32 */
|
||||
uint32_t flags; /* 0 if there's no unicode table */
|
||||
uint32_t numglyphs; /* number of glyphs */
|
||||
uint32_t bytesperglyph; /* size of each glyph */
|
||||
uint32_t height; /* height in pixels */
|
||||
uint32_t width; /* width in pixels */
|
||||
};
|
||||
typedef struct psf_font psf_font_t;
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue