Maps kernel into virtual space

src/elf.c

@@ -57,6 +57,9 @@ void load_elf(elf_header* elf_start)
         }
         }
     }
     }
 
 
+    // Map the kernel 1:1 in memory
+    page_region(pgdir, 0x0, &_kernel_end);
+
     // Allocate two more pages for stack
     // Allocate two more pages for stack
     page_map(pgdir, highest_vpage + 0x1000);
     page_map(pgdir, highest_vpage + 0x1000);
     page_map(pgdir, highest_vpage + 0x2000);
     page_map(pgdir, highest_vpage + 0x2000);

src/mem.c

@@ -85,6 +85,23 @@ void page_everything(page_directory_entry* pg_dir)
     }
     }
 }
 }
 
 
+// page_region adds page tables to map to real memory for a region
+void page_region(page_directory_entry pgdir[], void* begin, void* end)
+{
+    for (void* page = begin; page < end; page += 0x1000)
+    {
+        if ((pgdir[(uint32_t)page>>22] & 0xfffff000) == 0)
+        {
+            pgdir[(uint32_t)page>>22] |= (page_directory_entry)page_new_table();
+        }
+        page_table_entry* page_table = (page_table_entry*) ((uint32_t) pgdir[(uint32_t)page>>22] & 0xfffff000);
+        if ((page_table[((uint32_t)page >> 12) % 1024] & 0xfffff000) == 0)
+        {
+            page_table[((uint32_t)page>>12)%1024] |= (page_table_entry)page;
+        }
+    }
+}
+
 // This goes through all available memory, and maps 1 to 1 virtual memory to it.
 // This goes through all available memory, and maps 1 to 1 virtual memory to it.
 page_directory_entry* mem_init_kern_tables(multiboot_memory_map* mmap, multiboot_memory_map* mmap_end)
 page_directory_entry* mem_init_kern_tables(multiboot_memory_map* mmap, multiboot_memory_map* mmap_end)
 {
 {

src/mem.h

@@ -38,6 +38,7 @@ extern char _kernel_end[];
 void* page_allocate();
 void* page_allocate();
 void page_free(void* page_start);
 void page_free(void* page_start);
 void* page_map(page_directory_entry pgdir[], void* page_start);
 void* page_map(page_directory_entry pgdir[], void* page_start);
+void page_region(page_directory_entry pgdir[], void* begin, void* end);
 
 
 // Initilization
 // Initilization
 void page_everything(page_directory_entry* pg_dir);
 void page_everything(page_directory_entry* pg_dir);