pgmap.c

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/*
 * kernel_arch/i386/kernel/memory/pgmap.c
 *
 * Copyright (c) 2003-2004 Lukasz Dembinski <dembol@nasa.com.pl>
 * All Rights Reserved
 * 
 * Date:        2004/01
 * Author:      Lukasz Dembinski
 * Info:        pgmap.c core file
 * Contact:     mailto: <dembol@nasa.com.pl>
 *
 */

#include <agnix/agnix.h>
#include <agnix/init.h>
#include <agnix/memory.h>
#include <asm/paging.h>
#include <asm/cpu_ops.h>
#include <agnix/console.h>

#define DEBUG_MEM               0
#define MOD_NAME                "MEM: "

extern struct main_memory_s main_memory;

struct pte_s *pte_ptr(struct pde_s *pde)
{
    struct pte_s *pte;
    
    if (!pte_address(pde)) {
        pte = (struct pte_s *)get_free_pages(0);
        pde->pte_addr = virt_to_phys((u32)pte);
        set_pde(pde, make_pde_phys(pde->pte_addr, PDE_FLAG_P | PDE_FLAG_RW));
    } else {
        pte = phys_to_virt(pte_address(pde));
    }
    
    return pte;
}

int remap_page_tables(u32 pd_addr, u32 from, u32 to, u32 len)
{
    

    return 0;    
}

int remap_kpage_tables(u32 from, u32 to, u32 len)
{
    return remap_page_tables(main_memory.pdbr, from, to, len);
}

int page_tables_init(struct main_memory_s *mem)
{
    struct pde_s *pde;
    struct pte_s *pte;
    u32    page_start;
    u32    page_end;
    u32    page_len;
    u32    page_count;
    int    i, j;

#if DEBUG_MEM    
    printk(MOD_NAME "Initializing page tables\n");
#endif

    page_count = 0;
    page_start = 0;
    page_end   = (mem->mem_size) >> 2; // KB >> 2 == pages 
    page_len = page_end - page_start;

    pde = (struct pde_s *)mem->pdbr;
    pde += pde_offset(PAGE_OFFSET);

#if DEBUG_MEM
    printk(MOD_NAME "page count = %d\n", page_len);
#endif

    __cli();

//    write_cr4(read_cr4() | 0x10);

    for (i = pde_offset(PAGE_OFFSET); i < PDE_PER_PD; i++) {

//      pde->pte_addr = (page_count << PAGE_SHIFT);     
//      set_pde(pde, make_pde_phys(pde->pte_addr, PDE_FLAG_P | PDE_FLAG_RW | PDE_FLAG_PS));
//      pde++;
//      page_count += 1024;
//    
        pte = pte_ptr(pde);
        for (j = 0; j < PTE_PER_PT; j++) {

            set_pte(pte, make_pte_phys(page_count << PAGE_SHIFT, (PTE_FLAG_P | PTE_FLAG_RW | PTE_FLAG_A | PTE_FLAG_D)));                

            if (++page_count >= page_len)
                break;

            pte++;
        }
        
        if (page_count >= page_len)
            break;
        
        pde++;
    }


#if DEBUG_MEM
    printk(MOD_NAME "Loading cr3 (phys_addr=%x) ... ", virt_to_phys(mem->pdbr));
#endif

    load_cr3(mem->pdbr);
    
#if DEBUG_MEM
    printk("ok\n");
#endif

    return 0;
}