paging.c File Reference

#include "../../pmem.h"
#include "../../vga_err.h"
#include "../halt.h"
#include "../paging.h"
#include "arch_consts.h"
#include <stdint.h>
#include <stdlib.h>

Functions
static char	is_page_present (size_t page)
void	map_pages (void *virt_addr_ptr, void *phys_addr_ptr, int num_pages, char usr, char wr)
void *	find_free_pages (int num_pages)
void *	alloc_pages (int num_pages)
void *	virt_to_phys (void *virt_addr_arg)
void	alloc_pages_virt (int num_pages, void *addr)
static void	invl_page (void *addr)
void *	paging_new_address_space ()
void	load_address_space (void *cr3)
void	unmap_pages (void *start_virt, int num_pages)
void	paging_init ()
void *	get_cr3 ()

Variables
static uint32_t	page_directory [1024]
	The kernel process's page directory.
static uint32_t	kern_page_tables [NUM_KERN_FRAMES]
	The page tables where the kernel binary is mapped in.
static uint32_t	kstack_page_tables [218 *1024]
	Page tables for thread kernel stacks.
static uint32_t	kmalloc_page_tables [4 *1024]
	Page tables for the kmalloc heap.
static uint32_t *	pagdirmap =(uint32_t*)0xFFFFF000
	Pointer to the page directory entries in the recursive mapping.
static uint32_t *	page_table_map =(uint32_t*)0xFFC00000
	Pointer to the page table entries in the recursive mapping.

Function Documentation

alloc_pages()

void* alloc_pages

(

int

num_pages

)

Allocate virtual pages & map them to physical memory.

Parameters

num_pages

The number of pages to allocate.

Returns

a pointer to the allocated pages.

alloc_pages_virt()

void alloc_pages_virt	(	int	num_pages,
		void *	addr
	)

Allocate virtual pages at a specific address & map them to physical memory.

Parameters

num_pages	The number of pages to allocate.
addr	The adress to start allocation at.

find_free_pages()

void* find_free_pages

(

int

num_pages

)

Finds free virtual pages and returns the start address

Parameters

num_pages

The minimum size of the free area

Returns

the start of the free area

get_cr3()

void* get_cr3

(

)

Get the current address space

Returns

a pointer to the current address space in physical memory.

invl_page()

static void invl_page ( void *  addr )

static

Invalidates a page in the TLB,

Parameters

addr	The address of the page to invalidate.

is_page_present()

static char is_page_present ( size_t  page )

static

Checks whether a page is present

Parameters

page	The page number to check

Returns

Whether the page is present

load_address_space()

void load_address_space

(

void *

cr3

)

Load an address space

Parameters

cr3	The address space to load

map_pages()

void map_pages	(	void *	virt_addr_ptr,
		void *	phys_addr_ptr,
		int	num_pages,
		char	usr,
		char	wr
	)

Map virtual pages to physical frames.

Parameters

virt_addr_ptr	The start of the virtual range to map.
phys_addr_ptr	The start of the physical range to map.
num_pages	The number of pages to map.
usr	Are the pages acessible by user mode code
wr	Are the pages writable by user mode code (kernel always has write permissions)

paging_init()

void paging_init

(

)

Initialize paging

paging_new_address_space()

void* paging_new_address_space

(

)

Create a new address space

Returns

a pointer to the new address space in physical memory.

unmap_pages()

void unmap_pages	(	void *	start_virt,
		int	num_pages
	)

Unmap virtual pages,

Parameters

start_virt	The start of the virtual range to unmap.
num_pages	The number of pages to map.

virt_to_phys()

void* virt_to_phys

(

void *

virt_addr

)

Convert a virtual address to a physical one.

Parameters

virt_addr

The virtual address to convert

Returns

the physical adress it maps to, or NULL if it is not mapped.