1 // Copyright 2023, The Android Open Source Project
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 //! Utility functions.
16
17 pub(crate) const SIZE_4KB: usize = 4 << 10;
18
19 /// Computes the low memory page address of the 4KiB page containing a given address.
page_address(addr: usize) -> u6420 pub(crate) fn page_address(addr: usize) -> u64 {
21 (addr & !(SIZE_4KB - 1)).try_into().unwrap()
22 }
23