Vysokopůlní jádro. (3f2fdf00) · Commits · Adam Matoušek / pb173-bootable-thing

Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -13,7 +13,7 @@ boot.img: a.out
		$(MKRESCUE) -o $@ _boot
		rm -rf _boot

		a.out: mem/paging.o dev/io.o kernel.o boot.o
		a.out: mem/paging.o dev/io.o kernel.o boot.o util.o
		$(LD) -o $@ -T linkscript $(CFLAGS) $(LDFLAGS) $^

		%.o: %.cpp

boot.S

+86 −14

Original line number	Diff line number	Diff line
		#define ASM_FILE 1
		// Stack size shall be at most 4M
		#define STACK_SIZE 0x4000
		#define HIGHER_HALF 0xC0000000
		#define VIRT_STACK 0xFFC00000
		#include "multiboot2.h"

		.text

		.globl start, _start
		start:
		_start:
		jmp multiboot_entry

		.section .multiboot
		.align 8 /* required multiboot header alignment */
		multiboot_header:
		.long MULTIBOOT2_HEADER_MAGIC
		@@ -17,23 +14,78 @@ multiboot_header:
		.long -( MULTIBOOT2_HEADER_MAGIC + MULTIBOOT_ARCHITECTURE_I386 \
		+ ( multiboot_header_end - multiboot_header ) )

		.align 8 /* each tag must be aligned separately */
		.short MULTIBOOT_HEADER_TAG_ADDRESS
		.short 0 /* flags */
		.long 24 /* tag size */
		.long (multiboot_header - HIGHER_HALF) /* header address */
		.long (_kernel_start - HIGHER_HALF) /* load address */
		.long (_kernel_end - HIGHER_HALF) /* load end address */
		.long (_bss_end - HIGHER_HALF) /* bss end address */


		.align 8 /* each tag must be aligned separately */
		.short MULTIBOOT_HEADER_TAG_ENTRY_ADDRESS
		.short 0 /* flags */
		.long 12 /* tag size */
		.long (start - HIGHER_HALF) /* entry address */

		.align 8 /* each tag must be aligned separately */
		.short MULTIBOOT_HEADER_TAG_END /* tag id */
		.short 0 /* flags */
		.long 8 /* tag size */
		multiboot_header_end:

		.text

		.globl start, _start
		.type _start, @function

		#define VIDEO 0xC00B8000

		_start:
		start:
		multiboot_entry:
		movl $(stack + STACK_SIZE), %esp /* stack pointer */

		movl %eax, %esi
		movl %ebx, %edi

		movl $(page_directory - HIGHER_HALF), %eax
		movl %eax, %cr3 # Set phys. addr. of page directory
		mov %cr4, %eax
		or $0x00000010, %eax # Enable PSE
		mov %eax, %cr4
		mov %cr0, %eax
		or $0x80000001, %eax # Enable paging
		mov %eax, %cr0

		mov $higher, %eax
		jmp *%eax

		higher:
		/* map the stack base to 4G minus 4M */
		movl $((STACK_SIZE >> 12) - 1), %ecx
		loop1:
		movl %ecx, %ebx
		shl $12, %ebx
		add $(stack - HIGHER_HALF), %ebx
		or $0x3, %ebx
		mov %ecx, %eax
		shl $2, %eax
		add $(stack_pgtbl + 0x1000 - (STACK_SIZE >> 10) ), %eax
		movl %ebx, (%eax)
		dec %ecx
		jns loop1

		movl $VIRT_STACK, %esp # Map stack to a new virt. addr.
		pushl $0
		popf /* reset EFLAGS */
		popf

		pushl %edi /* multiboot information structure */
		pushl %esi /* multiboot magic value */
		call main

		pushl %ebx /* multiboot information structure */
		pushl %eax /* multiboot magic value */
		call main /* let's C */
		jmp pre_halt

		#define VIDEO 0xB8000
		pre_halt:
		mov $2, %ecx
		loop_flags_row:
		@@ -61,6 +113,26 @@ empty:
		hlt
		#undef VIDEO

		#define HH_PGDIR_IDX (HIGHER_HALF >> 22)
		.section .paging
		.global page_directory
		.align 0x1000
		page_directory:
		.long 0x00000083 # Id-map low 4M
		.fill (HH_PGDIR_IDX - 1), 4, 0x0 # Nothing
		.long 0x00000083 # Map low 4M to HIGHER_HALF
		.fill (1021 - HH_PGDIR_IDX), 4, 0x0 # Nothing
		.long (stack_pgtbl - HIGHER_HALF + 0x3) # Page table for the stack
		.long 0x00000000

		.align 0x1000
		stack_pgtbl:
		.fill 1020, 4, 0x0 # Nothing
		.long (stack - HIGHER_HALF + 0x3) # Four static stack pages
		.long (stack - HIGHER_HALF + 0x1003)
		.long (stack - HIGHER_HALF + 0x2003)
		.long (stack - HIGHER_HALF + 0x3003)

		halt_message:
		.asciz " Nyni muzete pocitac bezpecne vypnout "
		.comm stack, STACK_SIZE /* the stack */

dev/vga.hpp

+7 −1

Original line number	Diff line number	Diff line
		@@ -7,7 +7,8 @@ namespace masys {
		namespace dev {

		class Vga : public CharacterOutput {
		u8 * const video = ( u8 * ) 0xB8000;

		u8 * const video;
		const int columns = 80;
		const int lines = 24;

		@@ -15,6 +16,11 @@ class Vga : public CharacterOutput {
		y = 0,
		flags = 0x07;
		public:
		static const u32 MEMORY_MAPPED = 0xB8000;

		Vga( u8 * fb_addr )
		: video( fb_addr ) {}

		Status putch( u8 c ) {
		if ( c == '\b' && x > 0 ) {
		--x;

kernel.cpp

+34 −30

Original line number	Diff line number	Diff line
		#include <dev/vga.hpp>
		#include <dev/serial.hpp>
		#include <mem/paging.hpp>
		#include <util.hpp>
		#include <multiboot2.h>

		namespace masys {

		const size_t PAGE_SIZE = 4096;

		alignas( PAGE_SIZE ) mem::PageEntry page_directory[ PAGE_SIZE ];

		void kernel( unsigned long magic, unsigned long addr )
		{
		dev::Vga vga;
		vga.clear();
		extern "C" {

		vga.puts( "Enabling paging...\n" );
		extern masys::mem::PageEntry page_directory[];

		for ( auto & pgdir_entry : page_directory )
		{
		pgdir_entry._raw = 0;
		}
		auto & mypage = page_directory[ 1 << 8 ];
		mypage.present = 1;

		mem::enable_paging( page_directory );
		namespace masys {

		const size_t PAGE_SIZE = 0x1000;
		const size_t PAGEDIR_ENTRIES = 1024;
		const u32 HIGHER_HALF = 0xC0000000;

		if ( magic != MULTIBOOT2_BOOTLOADER_MAGIC )
		void kernel( unsigned long magic, unsigned long addr )
		{
		vga.puts( "invalid magic number :-(" );
		return;
		}
		dev::SerialLine ser( dev::SERIAL_PORT_1 );

		if ( addr & 7 )
		{
		vga.puts( "unaligned mbi :-(" );
		return;
		}
		char buf[32];
		ser.puts( "Page Directory address: 0x" );
		itoa( (u32) page_directory, buf, 16 );
		ser.puts( buf );
		ser.putch( '\n' );
		ser.puts( "Stack pointer: 0x" );
		itoa( (u32) buf, buf, 16 );
		ser.puts( buf );
		ser.putch( '\n' );
		ser.puts( "Multiboot info address: 0x" );
		itoa( addr, buf, 16 );
		ser.puts( buf );
		ser.putch( '\n' );

		dev::Vga vga( (u8*) dev::Vga::MEMORY_MAPPED + HIGHER_HALF );
		vga.clear();
		vga.puts( "\nSwitched.\n" );

		// TODO: Don't assume that multiboot info is in lower 4M
		vga.puts( "Co nam Multiboot povedel:\n================================\n" );

		auto tag = reinterpret_cast< multiboot_tag * >( addr + 8 );
		@@ -58,11 +60,12 @@ void kernel( unsigned long magic, unsigned long addr )
		+ tag->size + 7 ) & 0xfffffff8UL );
		}

		vga.puts( "Nyni ocekavam vstup na seriove lince (coz je stdin, ehm).\n" );
		vga.puts( "^D ukonci cinnost tohoto bohorovneho jadra.\n\n" );
		/* Cancel id-mapping */
		page_directory[ 0 ].present = 0;

		vga.puts( "Nyni ocekavam vstup na seriove lince.\n" );
		vga.puts( "^D ukonci cinnost tohoto bohorovneho jadra.\n\n" );

		dev::SerialLine ser( dev::SERIAL_PORT_1 );
		ser.puts( "Ahoj svete za seriovou linkou! Povez mi neco:\n" );

		const char CTRL_D = 4;
		@@ -74,6 +77,7 @@ void kernel( unsigned long magic, unsigned long addr )
		ser.putch( a );
		} while ( a != CTRL_D );

		ser.puts( "\nKernel konec.\n" );
		vga.puts( "\nKernel konec.\n" );
		}

linkscript

+11 −7

Original line number	Diff line number	Diff line
		@@ -6,37 +6,41 @@ ENTRY(_start)
		kernel image. */
		SECTIONS
		{
		/* Begin putting sections at 1 MiB, a conventional place for kernels to be
		loaded at by the bootloader. */
		. = 1M;
		/* This is a higher half kernel, virtually at 1G+1M, physically at 1M */
		. = 0xC0100000;

		_kernel_start = .;
		/* 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)
		.text BLOCK(4K) : AT(ADDR(.text) - 0xC000000)
		{
		*(.multiboot)
		*(.text)
		}

		/* Read-only data. */
		.rodata BLOCK(4K) : ALIGN(4K)
		.rodata BLOCK(4K) : AT(ADDR(.rodata) - 0xC000000)
		{
		*(.rodata)
		}

		/* Read-write data (initialized) */
		.data BLOCK(4K) : ALIGN(4K)
		.data BLOCK(4K) : AT(ADDR(.data) - 0xC000000)
		{
		*(.paging)
		*(.data)
		}

		_kernel_end = .;

		/* Read-write data (uninitialized) and stack */
		.bss BLOCK(4K) : ALIGN(4K)
		.bss BLOCK(4K) : AT(ADDR(.bss) - 0xC000000)
		{
		*(COMMON)
		*(.bss)
		}
		_bss_end = .;

		/* 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. */