github.com/sagernet/gvisor@v0.0.0-20240428053021-e691de28565f/pkg/hostarch/hostarch_arm64.go (about)

     1  // Copyright 2019 The gVisor Authors.
     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  //go:build arm64
    16  // +build arm64
    17  
    18  package hostarch
    19  
    20  import (
    21  	"encoding/binary"
    22  
    23  	"golang.org/x/sys/unix"
    24  )
    25  
    26  const (
    27  	// PageSize is the system page size.
    28  	// arm64 support 4K/16K/64K page size,
    29  	// which can be get by unix.Getpagesize().
    30  	// Currently, only 4K page size is supported.
    31  	PageSize = 1 << PageShift
    32  
    33  	// HugePageSize is the system huge page size.
    34  	HugePageSize = 1 << HugePageShift
    35  
    36  	// CacheLineSize is the size of the cache line.
    37  	CacheLineSize = 1 << CacheLineShift
    38  
    39  	// PageShift is the binary log of the system page size.
    40  	PageShift = 12
    41  
    42  	// HugePageShift is the binary log of the system huge page size.
    43  	// Should be calculated by "PageShift + (PageShift - 3)"
    44  	// when multiple page size support is ready.
    45  	HugePageShift = 21
    46  
    47  	// CacheLineShift is the binary log of the cache line size.
    48  	CacheLineShift = 6
    49  )
    50  
    51  var (
    52  	// ByteOrder is the native byte order (little endian).
    53  	ByteOrder = binary.LittleEndian
    54  )
    55  
    56  func init() {
    57  	// Make sure the page size is 4K on arm64 platform.
    58  	if size := unix.Getpagesize(); size != PageSize {
    59  		panic("Only 4K page size is supported on arm64!")
    60  	}
    61  }