Files
bsb2/kernel/memory/pagetable.cc
2026-02-10 16:18:19 +01:00

102 lines
2.6 KiB
C++

#include "pagetable.h"
void load_cr3( void* cr3_value ) {
asm volatile("mov %0, %%cr3" :: "r"((uint64_t)cr3_value) : "memory");
}
void create_basic_page_table(four_lvl_paging_t* table){
//pagedirectory_entry_t *l4 = (pagedirectory_entry_t *)(base + (0 * 4096));
//pagedirectory_entry_t *l3 = (pagedirectory_entry_t *)(base + (1 * 4096));
//pagedirectory_entry_t *l2 = (pagedirectory_entry_t *)(base + (2 * 4096));
//pagetable_entry_t *l1 = (pagetable_entry_t *) (base + (7 * 4096));
table->l4.entries[0] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l3) >> 12,
};
table->l3.entries[0] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l2) >> 12,
};
//kernel memory
//for(uintptr_t i=0; i<0x4000000/(2*1024*1024); i++){
// table->l2.entries[i] = {
// .present = 1,
// .write = 1,
// .user = 1,
// .pat = 1, //2MB pages
// .address = i,
// };
//}
//kernel memory
for(uint32_t i=0; i<KERNEL_MEMORY_BORDER/4096/512; i++){
table->l2.entries[i] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l1[i]) >> 12,
};
}
for(uintptr_t i=0; i<KERNEL_MEMORY_BORDER/4096; i++){
table->l1[i/512].entries[i%512] = {
.present = 1,
.write = 1,
.user = 0,
.address = i,
};
}
//add ioapic address to pagetable
table->l3.entries[3] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l2_apic) >> 12,
};
table->l2_apic.entries[502] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->ioapic) >> 12,
};
table->ioapic.entries[0] = {
.present = 1,
.write = 1,
.user = 0,
.address = 0xFEC00,
};
//lapic
table->l2_apic.entries[503] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->lapic) >> 12,
};
table->lapic.entries[0] = {
.present = 1,
.write = 1,
.user = 0,
.address = 0xFEE00,
};
//unmap 0 page
table->l1[0].entries[0].present = 0;
}
void map_pageframe(four_lvl_paging_t* table, uintptr_t phys, uintptr_t virt){
uint64_t pagefr_nr = phys / 4096;
table->l1[pagefr_nr/512].entries[pagefr_nr%512].address = virt >> 12;
table->l1[pagefr_nr/512].entries[pagefr_nr%512].present = 1;
}