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Code: Select all

//paging.c
#include "../../../include/arch/i686/paging.h"

#include <stdint.h>
#include <stddef.h>

#include "../../../include/stdio.h"

page_directory_t pgdir[1024] __attribute__((aligned(4096)));
page_table_t     pgtbl[1024] __attribute__((aligned(4096)));

void setup_pgdir(page_directory_t pgdir[1024])
{
    for(int i=0; i<1024; i++)
    {
        //Those page directory entries AREN'T USABLE. It just fills all page directory by not present page tables.
        pgdir[i].present    = 0;
        pgdir[i].rw_flag    = 1;
        pgdir[i].access_lvl = 0;
    }
}

void paging_ident(uint32_t* tbl)
{
    size_t size=4096*1024;
    uint32_t from=0x0;
    //Code from OSDev.org.
    from &= 0xfffff000; // discard bits we don't want
    for(;size>0;from+=4096,size-=4096,tbl++)
    {
        *tbl=from|1;     // mark page present.
    }
}

void setup_paging()
{
    void load_pg_dir(uint32_t*);
    void paging_enable(void);
    setup_pgdir(pgdir);
    paging_ident((uint32_t*)pgtbl);
    load_pg_dir((uint32_t*)pgdir);
    paging_enable();
}
//paging.h
#ifndef PAGING_H
#define PAGING_H

typedef struct page_directory_t page_directory_t;
typedef struct page_table_t page_table_t;

struct page_directory_t
{
    int present       : 1;
    int rw_flag       : 1;
    int access_lvl    : 1; //0 is for only ring0. 1 is for anybody.
    int write_through : 1;
    int cache_off     : 1;
    int accessed      : 1;
    int zero          : 1;
    int page_size     : 1;
    int reserved      : 3;
    int tbl_addr      : 21;
};

struct page_table_t
{
    int present       : 1;
    int rw_flag       : 1;
    int access_lvl    : 1; //0 is for only ring0. 1 is for anybody.
    int cache_off     : 1;
    int accessed      : 1;
    int dirty         : 1;
    int zero          : 1;
    int global        : 1;
    int reserved      : 3;
    int tbl_addr      : 21;
};

void load_page_directory(page_directory_t);

#endif // PAGING_H
//paging.asm
global load_pg_dir
load_pg_dir: 
        ; Loaging page directory.
	push ebp
	mov ebp, esp
	mov eax, [esp+8]
	mov cr3, eax
	mov esp, ebp
	pop ebp
	ret
global paging_enable
paging_enable: ; Enable the paging by setting bit in CR0.
	push ebp
	mov ebp, esp
	mov eax, cr0
	or eax, 0x80000000
	mov cr0, eax ; Here it crashes, noo :(
	mov esp, ebp
	pop ebp
	ret

Code: Select all

#define MAKE_PML4E(base, avl, pcd, pwt, us, rw, p) \
  (uint64_t)( \
  (base << 12) | \
  (avl << 9) | \
  (pcd << 4) | \
  (pwt << 3) | \
  (us << 2) | \
  (rw << 1) | \
  p)

Code: Select all

#include "../../../include/arch/i686/paging.h"

#include <stdint.h>
#include <stddef.h>

#include "../../../include/stdio.h"

// DEPRECATED
page_directory_t pgdir[1024] __attribute__((aligned(4096)));
page_table_t     pgtbl[1024] __attribute__((aligned(4096)));

void setup_pgdir(page_directory_t pgdir[1024])
{
    for(int i=0; i<1024; i++)
    {
        //Those page directory entries AREN'T USABLE. It just fills all page directory by not present page tables.
        pgdir[i].present    = 0;
        pgdir[i].rw_flag    = 1;
        pgdir[i].access_lvl = 0;
    }
}

void paging_ident(page_table_t *tbl)
{
    //Identity map first 4 megabytes of memory.
    size_t size=1024;
    uint32_t mem=0x0;
    for(size_t i=0; i<size; i++, mem+=PAGE_SIZE)
    {
        tbl[i].rw_flag   =1;
        tbl[i].access_lvl=0;
        tbl[i].phys_addr =mem;
        tbl[i].cache_off =1;
        tbl[i].present =1;

    }
}

void setup_paging()
{
    void load_pg_dir(page_directory_t *);
    void paging_enable(void);
    setup_pgdir(pgdir);
    paging_ident(pgtbl);
    pgdir[0].tbl_addr=pgtbl;
    pgdir[0].present    = 1;
    load_pg_dir(pgdir);
    paging_enable();
}