syscalls: start adding exit syscall, not done yet

src/mm/paging.c

@@ -146,3 +146,27 @@ uint32_t* create_page_dir()
 
     return new_pd;
 }
+
+void destroy_page_dir(uint32_t* page_dir) {
+    // Iterate through all page directory entries
+    for (int i = 0; i < 1024; i++) {
+        if (page_dir[i] & 1) {  // If page table exists
+            uint32_t* page_table = (uint32_t*)(page_dir[i] & 0xFFFFF000);
+            
+            // Free all user pages (0-767)
+            if (i < 768) {
+                for (int j = 0; j < 1024; j++) {
+                    if (page_table[j] & 1) {
+                        free_page((void*)(page_table[j] & 0xFFFFF000));
+                    }
+                }
+            }
+            
+            // Free the page table itself
+            free_page(page_table);
+        }
+    }
+    
+    // Free the page directory
+    free_page(page_dir);
+}