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#include "paging.h"
#include "exceptions.h"
#include <stdint.h>
extern uint32_t endkernel;
Page_Directory make_pagedir(Page_Table *addr, uint8_t flags) {
return ((uint32_t)addr & 0xFFFFF000) | flags;
}
Page_Table make_pagetable(uint32_t addr, uint8_t flags) {
return ((uint32_t)addr & 0xFFFFF000) | flags;
}
Page_Directory page_dir[1024] __attribute__((aligned(4096)));
Page_Table pgtable[1024] __attribute__((aligned(4096)));
void idpaging(uint32_t *first_pte, uint32_t from, int size) {
for (; size > 0; from += 4096, size -= 4096, first_pte++) {
*first_pte = make_pagetable(from, 3); // mark page present.
}
}
void genDirs() {
for (int i = 0; i < 1024; i++) {
page_dir[i] = make_pagedir(0x0, 2);
for (int j = 0; j < 1024; j++)
((uint32_t *)(page_dir[i] & 0xFFFFF000))[j] &= 0xFFFFFFFE;
}
page_dir[1023] = make_pagetable((uint32_t)page_dir, 3);
idpaging(&pgtable[0], 0x0, 1024 * 0x800);
page_dir[0] = make_pagedir(pgtable, 3);
}
void *get_physaddr(void *virtualaddr) {
unsigned long pdindex = (unsigned long)virtualaddr >> 22;
unsigned long ptindex = (unsigned long)virtualaddr >> 12 & 0x03FF;
unsigned long *pd = (unsigned long *)0xFFFFF000;
if (!(pd[pdindex] & 1))
return 0x0;
unsigned long *pt = ((unsigned long *)0xFFC00000) + (0x400 * pdindex);
if (!(pt[ptindex] & 1))
return 0x0;
return (void *)((pt[ptindex] & ~0xFFF) +
((unsigned long)virtualaddr & 0xFFF));
}
void map_page(void *physaddr, void *virtualaddr, uint8_t flags) {
unsigned long pdindex = (unsigned long)virtualaddr >> 22;
unsigned long ptindex = (unsigned long)virtualaddr >> 12 & 0x03FF;
unsigned long *pd = (unsigned long *)0xFFFFF000;
if (!(pd[pdindex] & 1)) {
pd[pdindex] =
make_pagedir((uint32_t *)0xFFC00000 + (0x400 * pdindex), 3);
}
unsigned long *pt = ((unsigned long *)0xFFC00000) + (0x400 * pdindex);
if (!(pt[ptindex] & 1))
panic("Unimplemented - map_page - pt[%d]", ptindex);
pt[ptindex] = ((unsigned long)physaddr) | (flags & 0xFFF) | 0x01; // Present
}
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