not working

kernel/main.cc

@@ -4,6 +4,7 @@
 #include "./types.h"  // This is actually used
 #include "arch/core_interrupt.h"
 #include "memory/pageframealloc.h"
+#include "memory/pagetable.h"
 #include "object/outputstream.h"
 #include "syscall/handler.h"
 
@@ -34,6 +35,8 @@ OutputStream* copyout = &copystream;
 #include "./user/app1/appl.h"
 #include "./user/app2/kappl.h"
 
+alignas(4096) four_lvl_paging_t paging_tree;
+
 static const uint32_t NUM_APPS = 9;
 Application apps[NUM_APPS];
 
@@ -41,7 +44,11 @@ static KeyboardApplication kapp;
 
 // Main function
 extern "C" int main() {
-    PageFrameAllocator::init();
+
+    //PageFrameAllocator::init();
+    memset(&paging_tree, 0, sizeof(four_lvl_paging_t));
+    create_basic_page_table((uintptr_t)&paging_tree);
+    load_cr3((void*)&paging_tree.l4);
 
 	tout.reset();
 	tout.setPos(33, 0);

kernel/memory/pageframe.h

@@ -6,13 +6,9 @@
 class PageFrame {
     private:
     public:
-        uintptr_t address;
-        uintptr_t mapped_address;
         bool available;
         PageFrame* queue_link;
+        uint16_t ref_count;
         PageFrame(){};
-        PageFrame(uintptr_t a):address(a){};
-        uintptr_t getAddr(){return address;};
-        uintptr_t getVirtualAddr(){return address;};
 };
 #endif

kernel/memory/pageframealloc.cc

@@ -15,6 +15,10 @@ void mark_pageframes(uintptr_t start, uintptr_t end, bool available){
     DBG << "start: " << hex << start << " end: " << end;
     start = Page::floor(start);
     end = Page::ceil(end);
+    if(start > 4294967296)
+        start = 4294967296;
+    if(end > 4294967296)
+        end = 4294967296;
     DBG << " page start: " << hex << start << " end: " << end << endl;
 
     for(uint64_t i = start; i < end; i += 4096){
@@ -116,7 +120,7 @@ PageFrame* PageFrameAllocator::alloc(bool kernel){
     }
     else{
         search_start = 0x4000000;
-        search_end = 0x8000000;
+        search_end = 0x8000000; //TODO find some appropriate value
     }
 
     uint64_t free_pageframe=0;

kernel/memory/pagetable.cc

@@ -0,0 +1,47 @@
+
+#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(uintptr_t base){
+    //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));
+    four_lvl_paging_t* table = (four_lvl_paging_t*)base;
+
+    table->l4 = {
+        .present = 0,
+        .write = 0,
+        .user = 0,
+        .address = 0, //(uintptr_t)&(table->l3) >> 12,
+    };
+
+    table->l3 = {
+        .present = 1,
+        .write = 1,
+        .user = 1,
+        .address = (uintptr_t)&(table->l2) >> 12,
+    };
+
+    for(uint32_t i=0; i<sizeof(table->l2)/sizeof(table->l2[0]); i++){
+        table->l2[i] = {
+            .present = 1,
+            .write = 1,
+            .user = 1,
+            .address = (uintptr_t)&(table->l1[i]) >> 12,
+        };
+    }
+
+    //kernel memory
+    for(uintptr_t i=0; i<0x40000000/4096; i++){
+        table->l1[i/512].entries[i%512] = {
+            .present = 1,
+            .write = 1,
+            .user = 0,
+            .address = i,
+        };
+    }
+
+}

kernel/memory/pagetable.h

@@ -0,0 +1,56 @@
+#ifndef _PAGETABLE_H_
+#define _PAGETABLE_H_
+
+#include "../types.h"
+
+typedef struct {
+    uint8_t present:1 = 0;
+    uint8_t write:1 = 0;
+    uint8_t user:1 = 0;
+    uint8_t pwt:1 = 0;
+    uint8_t cache_disable:1 = 0;
+    uint8_t accessed:1 = 0;
+    uint8_t dirty:1 = 0;
+    uint8_t pat:1 = 0;
+    uint8_t rsvd_0:4 = 0;
+    uint64_t address:39 = 0;
+    uint16_t rsvd_1:10 = 0;
+    uint8_t execute_disable:1 = 0;
+} pagetable_entry_t;
+
+typedef struct {
+    pagetable_entry_t entries[512];
+} pagetable_t;
+
+typedef struct {
+    uint8_t present:1 = 0;
+    uint8_t write:1 = 0;
+    uint8_t user:1 = 0;
+    uint8_t pwt:1 = 0;
+    uint8_t cache_disable:1 = 0;
+    uint8_t accessed:1 = 0;
+    uint8_t rsvd_0:6 = 0;
+    uint64_t address:39 = 0;
+    uint16_t rsvd_1:10 = 0;
+    uint8_t execute_disable:1 = 0;
+} pagedirectory_entry_t;
+
+typedef struct {
+    alignas(4096) pagedirectory_entry_t l4;
+    alignas(4096) pagedirectory_entry_t l3;
+    alignas(4096) pagedirectory_entry_t l2[1];
+    alignas(4096) pagetable_t l1[1];
+} four_lvl_paging_t;
+
+void create_basic_page_table(uintptr_t base);
+void load_cr3( void* cr3_value );
+
+//typedef struct {
+// same
+//} pagedirectory_pointertable_entry_t;
+
+//typedef struct {
+// same
+//} PML4_entry_t;
+
+#endif