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working on new paging structure

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This commit is contained in:
Eggert Jung
2026-02-24 02:15:36 +01:00
parent c644ba6e42
commit ec53b15ce1
5 changed files with 51 additions and 41 deletions
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56
kernel/memory/pagetable.cc
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@@ -1,58 +1,58 @@
#include "pagetable.h"
#include "pageframealloc.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));
void write_identity_map(pagetable_t* identity_table, uint64_t size){
for(uintptr_t i=0; i<size/4096; i++){
identity_table[i/512].entries[i%512] = {
.present = 1,
.write = 1,
.user = 0,
.address = i,
};
}
}
void create_basic_page_table(four_lvl_paging_t* table, pagetable_t* kernel_identity){
//pagetable_t* l2 = (pagetable_t*)PageFrameAllocator::alloc(true);
table->l4.entries[0] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l3) >> 12,
.address = ((uintptr_t)&(table->l3.entries[0])) >> 12,
};
table->l3.entries[0] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)&(table->l2) >> 12,
.address = ((uintptr_t)&(table->l2.entries[0])) >> 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,
.address = (uintptr_t)(&kernel_identity[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,
};
}
//write_identity_map(table->l1, KERNEL_MEMORY_BORDER);
//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] = {
@@ -89,6 +89,6 @@ void create_basic_page_table(four_lvl_paging_t* table){
};
//unmap 0 page
table->l1[0].entries[0].present = 0;
kernel_identity[0].entries[0].present = 0;
}