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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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8
kernel/main.cc
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@@ -42,7 +42,9 @@ OutputStream* copyout = &copystream;
#include "./user/app1/appl.h"
#include "./user/app2/kappl.h"
alignas(4096) four_lvl_paging_t paging_tree;
//alignas(4096) four_lvl_paging_t paging_tree;
//four_lvl_paging_t paging_tree;
pagetable_t identity_table[KERNEL_MEMORY_BORDER/4096/512];
//static const uint32_t NUM_APPS = 9;
//Application apps[NUM_APPS];
@@ -57,8 +59,8 @@ extern "C" int main() {
memcpy((void *)0x4000000, initrd->getStartAddress(), initrd->getSize());
mark_pageframes(0x4000000, 0x4000000 + initrd->getSize(), false);
memset(&paging_tree, 0, sizeof(four_lvl_paging_t));
create_basic_page_table(&paging_tree);
write_identity_map(identity_table, KERNEL_MEMORY_BORDER);
//create_basic_page_table(&paging_tree, identity_table);
//load_cr3((void*)&paging_tree.l4);
tout.reset();

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;
}

5
kernel/memory/pagetable.h
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@@ -41,13 +41,14 @@ typedef struct {
alignas(4096) pagetable_t l4;
alignas(4096) pagetable_t l3;
alignas(4096) pagetable_t l2;
alignas(4096) pagetable_t l1[KERNEL_MEMORY_BORDER/4096/512];
//pagetable_t l1_kernel;
alignas(4096) pagetable_t l2_apic;
alignas(4096) pagetable_t ioapic;
alignas(4096) pagetable_t lapic;
} four_lvl_paging_t;
void create_basic_page_table(four_lvl_paging_t* table);
void write_identity_map(pagetable_t* identity_table, uint64_t size);
void create_basic_page_table(four_lvl_paging_t* table, pagetable_t* kernel_identity);
void load_cr3(void* cr3_value);
void map_pageframe(four_lvl_paging_t* table, uintptr_t phys, uintptr_t virt);

22
kernel/thread/thread.cc
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@@ -9,7 +9,8 @@
#include "debug/output.h"
static int idCounter = 1; // counter for task IDs
extern four_lvl_paging_t paging_tree;
//extern four_lvl_paging_t paging_tree;
extern pagetable_t identity_table;
void Thread::kickoff(uintptr_t param1, uintptr_t param2, uintptr_t param3) {
Thread *thread = reinterpret_cast<Thread *>(param1);
@@ -29,19 +30,15 @@ void Thread::kickoff(uintptr_t param1, uintptr_t param2, uintptr_t param3) {
}
void Thread::load_paging(Thread* t){
paging_tree.l2.entries[32] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)(t->subtable) >> 12
};
load_cr3((void*)&paging_tree.l4);
load_cr3((void*)&(t->paging_tree.l4.entries[0]));
}
Thread::Thread (bool kernel, void * startframe, int num_pages): queue_link(nullptr), isKernel(kernel), start(startframe), id(idCounter++), kill_flag(false){
StackPointer.isr = reinterpret_cast<void *>((uintptr_t)PageFrameAllocator::alloc(true)+STACK_SIZE);//(reserved_stack_space_isr + STACK_SIZE);
StackPointer.user = (void*)(0x4100000+STACK_SIZE);
create_basic_page_table(&paging_tree, &identity_table);
subtable = (pagetable_t*) PageFrameAllocator::alloc(true);
for(uint8_t i=0; i<num_pages; i++){
subtable->entries[i] = {
@@ -58,6 +55,15 @@ Thread::Thread (bool kernel, void * startframe, int num_pages): queue_link(null
.address = user_stackframe_p >> 12
};
//pagetable_t* l2addr = (pagetable_t*)(paging_tree.l3.entries[0].address<<12);
//l2addr->entries[32] = {
paging_tree.l2.entries[32] = {
.present = 1,
.write = 1,
.user = 1,
.address = (uintptr_t)(subtable) >> 12
};
//map_pageframe(&paging_tree, (uintptr_t)StackPointer.user, 0x4001000);
prepareContext(StackPointer.isr, context, kickoff, reinterpret_cast<uintptr_t>(this), 0, 0);

1
kernel/thread/thread.h
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@@ -34,6 +34,7 @@ class Thread {
void* start;
four_lvl_paging_t paging_tree;
friend class Queue<Thread>;
friend class Semaphore;