/
paging.c
93 lines (72 loc) · 2.45 KB
/
paging.c
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#include "paging.h"
#include "io.h"
#include "memory_map.h"
#include "buddy_allocator.h"
#include "assert.h"
pte_t *pml4;
void force_pte(pte_t *pmle, int flags) {
if (!pte_present(*pmle)) {
void *npg;
if (flags & USE_BOOT_ALLOCATE) {
npg = get_mem(PAGE_SIZE, PAGE_SIZE);
} else {
npg = get_page0(0);
}
assert(npg != 0);
assert((pa(npg) & ((1 << 12) - 1)) == 0);
*pmle = pa(npg) | PTE_PRESENT | PTE_WRITE;
}
}
void map_adr(virt_t vad, phys_t pad, int flags) {
if (flags & USE_BIG_PAGE) {
assert((vad & ((1 << (12 + 9)) - 1)) == 0);
assert((pad & ((1 << (12 + 9)) - 1)) == 0);
} else {
assert((vad & ((1 << (12)) - 1)) == 0);
assert((pad & ((1 << (12)) - 1)) == 0);
}
pte_t *pml4e = pml4 + pml4_i(vad);
force_pte(pml4e, flags);
pte_t *pdpte = ((pte_t *) va(pte_phys(*pml4e) << 12)) + pml3_i(vad);
force_pte(pdpte, flags);
pte_t *pde = ((pte_t *) va(pte_phys(*pdpte) << 12)) + pml2_i(vad);
if (flags & USE_BIG_PAGE) {
assert(pte_present(*pde) == false);
*pde = pad | PTE_PRESENT | PTE_WRITE | PTE_LARGE;
flush_tlb_addr(vad);
return;
}
force_pte(pde, flags);
pte_t *pte = ((pte_t *) va(pte_phys(*pde) << 12)) + pml1_i(vad);
assert(pte_present(*pte) == false);
*pte = pad | PTE_PRESENT | PTE_WRITE;
if (!(flags & NOT_FLUSH_TLB)) {
flush_tlb_addr(vad);
}
}
phys_t get_phys_adr(virt_t vad) {
phys_t pad;
pte_t *pml4e = pml4 + pml4_i(vad);
pte_t *pdpte = ((pte_t *) va(pte_phys(*pml4e) << 12)) + pml3_i(vad);
pte_t *pde = ((pte_t *) va(pte_phys(*pdpte) << 12)) + pml2_i(vad);
if (pte_large(*pde)) {
pad = ((*pde & (~((1 << 21) - 1)))) | (vad & ((1 << 21) - 1));
return pad;
}
pte_t *pte = ((pte_t *) va(pte_phys(*pde) << 12)) + pml1_i(vad);
pad = ((*pte & (~((1 << 12) - 1)))) | (vad & ((1 << 12) - 1));;
return pad;
}
void map_init() {
pml4 = get_mem(PAGE_SIZE, PAGE_SIZE);
for (phys_t i = 0;
i < memory_map[memory_map_size - 1].base_addr + memory_map[memory_map_size - 1].length;
i += (1 << 21)) {
map_adr(i + HIGH_BASE, i, USE_BIG_PAGE | USE_BOOT_ALLOCATE | NOT_FLUSH_TLB);
if (i + KERNEL_BASE > HIGH_BASE) {
map_adr(i + KERNEL_BASE, i, USE_BIG_PAGE | USE_BOOT_ALLOCATE | NOT_FLUSH_TLB);
}
}
puts("init page mapping");
store_pml4(pa(pml4));
}