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#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "heap.h"
#include "isr.h"
#include "paging.h"
#include "panic.h"
uint32_t *current_directory;
static void page_fault(struct regs_t *regs)
{
volatile uint32_t fault_addr;
asm("mov %%cr2, %0" : "=r"(fault_addr));
printf("=== Page Fault ===\n");
printf("Faulting address: 0x%x\n", fault_addr);
/* dump the regs */
printf("EAX: 0x%x EBX: 0x%x\n", regs->eax, regs->ebx);
printf("ECX: 0x%x EDX: 0x%x\n", regs->ecx, regs->edx);
printf("ESP: 0x%x EBP: 0x%x\n", regs->esp, regs->ebp);
printf("ESI: 0x%x EDI: 0x%x\n", regs->esi, regs->edi);
printf("EIP: 0x%x\n", regs->eip);
panic("Page fault!\n");
}
void paging_switch_directory(uint32_t *dir)
{
current_directory = dir;
extern void do_paging_enable(uint32_t);
do_paging_enable((uint32_t)current_directory);
}
static uint32_t *identity_map_table(uint32_t start, int flags)
{
/* make a page table */
uint32_t *table = kmalloc_a(0x1000);
/* identity map 4MB */
for(uint32_t i = start; i < start + 1024; ++i)
{
table[i - start] = (i * PAGE_SIZE) | flags;
}
return table;
}
void paging_init(void)
{
uint32_t *kernel_directory = kmalloc_a(0x1000);
memset(kernel_directory, 0, 0x1000);
/* blank the kernel directory */
for(int i = 0; i < 1024; ++i)
{
kernel_directory[i] = PAGE_RW;
}
/* identity map all 4GB (and allocate all page tables) */
for(int i = 0; i < 1024; ++i)
kernel_directory[i] = (uint32_t)identity_map_table(i * 1024, PAGE_PRESENT | PAGE_RW) |
PAGE_PRESENT | PAGE_RW;
set_interrupt_handler(14, page_fault);
paging_switch_directory(kernel_directory);
}
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