Bootloader

Set of functions and variables for booting the kernel. More...

Macros
#define	KERNEL_STACK_SIZE   0x100000
	Size of the kernel's stack.
#define	SERIAL_COM1   (0x03F8)
	Serial port for QEMU.

Functions
void	boot_kernel (uint32_t stack_pointer, uint32_t entry, struct boot_info_t *boot_info)
	External function implemented in boot.S. More...
static void	__outportb (uint16_t port, uint8_t data)
	Use this to write to I/O ports to send bytes to devices. More...
static void	__debug_putchar (char c)
	Writes the given character on the debug port. More...
static void	__debug_puts (char *s)
	Writes the given string on the debug port. More...
static uint32_t	__align_rup (uint32_t addr, uint32_t value)
	Align memory address to the specified value (round up). More...
static uint32_t	__align_rdown (uint32_t addr, uint32_t value)
	Align memory address to the specified value (round down). More...
static void	__setup_pages (uint32_t pfn_virt_start, uint32_t pfn_phys_start, uint32_t pfn_count)
	Prepares the page frames. More...
static void	__setup_boot_paging (void)
	Setup paging mapping all the low memory to two places: one is the physical address of the memory itself the other is in the virtual kernel address space.
static void	__get_kernel_low_high (elf_header_t *elf_hdr, uint32_t *virt_low, uint32_t *virt_high)
	Extract the starting and ending address of the kernel. More...
static uint32_t	__get_address_after_modules (multiboot_info_t *header)
	Returns the first address after the modules. More...
static void	__relocate_kernel_image (elf_header_t *elf_hdr)
	Relocate the kernel image. More...
void	boot_main (uint32_t magic, multiboot_info_t *header, uint32_t esp)
	Entry point of the bootloader. More...

Variables
char	_bootloader_start []
	Linker symbols for where the .data section of kernel.bin.o. More...
char	_bootloader_end []
	Linker symbol for where the bootloader ends.
static boot_info_t	boot_info
	Boot info provided to the kmain function.
static page_directory_t	boot_pgdir
	Boot page directory.
static page_table_t	boot_pgtables [1024]
	Boot page tables.

Detailed Description

Set of functions and variables for booting the kernel.

Function Documentation

__align_rdown()

static uint32_t __align_rdown ( uint32_t  addr, uint32_t  value  )

inlinestatic

Align memory address to the specified value (round down).

Parameters

addr	the address to align
value	the value used to align.

Returns

the aligned address.

__align_rup()

static uint32_t __align_rup ( uint32_t  addr, uint32_t  value  )

inlinestatic

Align memory address to the specified value (round up).

Parameters

addr	the address to align
value	the value used to align.

Returns

the aligned address.

__debug_putchar()

static void __debug_putchar ( char  c )

inlinestatic

Writes the given character on the debug port.

Parameters

c	the character to send to the debug port.

__debug_puts()

static void __debug_puts ( char *  s )

inlinestatic

Writes the given string on the debug port.

Parameters

s	the string to send to the debug port.

__get_address_after_modules()

static uint32_t __get_address_after_modules ( multiboot_info_t *  header )

inlinestatic

Returns the first address after the modules.

Parameters

header

The multiboot info structure from which we extract the info.

Returns

The address after the modules.

__get_kernel_low_high()

static void __get_kernel_low_high ( elf_header_t *  elf_hdr, uint32_t *  virt_low, uint32_t *  virt_high  )

static

Extract the starting and ending address of the kernel.

Parameters

elf_hdr	The elf header of the kernel.
virt_low	Output variable where we store the lowest address of the kernel.
virt_high	Output variable where we store the highest address of the kernel.

__outportb()

static void __outportb ( uint16_t  port, uint8_t  data  )

inlinestatic

Use this to write to I/O ports to send bytes to devices.

Parameters

port	The output port.
data	The data to write.

__relocate_kernel_image()

static void __relocate_kernel_image ( elf_header_t *  elf_hdr )

inlinestatic

Relocate the kernel image.

Parameters

elf_hdr

The elf header of the kernel.

__setup_pages()

static void __setup_pages ( uint32_t  pfn_virt_start, uint32_t  pfn_phys_start, uint32_t  pfn_count  )

static

Prepares the page frames.

Parameters

pfn_virt_start	The first virtual page frame.
pfn_phys_start	The first physical page frame.
pfn_count	The number of page frames.

boot_kernel()

void boot_kernel	(	uint32_t	stack_pointer,
		uint32_t	entry,
		struct boot_info_t *	boot_info
	)

External function implemented in boot.S.

Parameters

stack_pointer	The stack base pointer, usually at the end of the lowmem.
entry
boot_info

boot_main()

void boot_main	(	uint32_t	magic,
		multiboot_info_t *	header,
		uint32_t	esp
	)

Entry point of the bootloader.

Parameters

magic	The magic number coming from the multiboot assembly code.
header	Multiboot header provided by the bootloader.
esp	The initial stack pointer.

Variable Documentation

_bootloader_start

char _bootloader_start[]

extern

Linker symbols for where the .data section of kernel.bin.o.

Linker symbol for where the bootloader starts.