Zeroed page allocation

kernel/src/memory.rs

@@ -20,6 +20,14 @@ impl MemoryManager {
         self.get_free_pages(order).map(|addr| addr as *mut u8)
     }
 
+    pub fn zallocate_pages(&mut self, order: usize) -> Option<*mut u8> {
+        let ptr = self.allocate_pages(order)?;
+        unsafe {
+            ptr.write_bytes(0, PAGE_SIZE << order);
+        }
+        Some(ptr)
+    }
+
     /// # Safety
     /// This method assumes that `address` is in range of this allocator
     pub unsafe fn deallocate_pages(&mut self, address: *mut u8, order: usize) {