github.com/metacubex/gvisor@v0.0.0-20240320004321-933faba989ec/pkg/abi/linux/dev.go (about)

     1  // Copyright 2018 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  package linux
    16  
    17  // MakeDeviceID encodes a major and minor device number into a single device ID.
    18  //
    19  // Format (see linux/kdev_t.h:new_encode_dev):
    20  //
    21  // Bits 7:0   - minor bits 7:0
    22  // Bits 19:8  - major bits 11:0
    23  // Bits 31:20 - minor bits 19:8
    24  func MakeDeviceID(major uint16, minor uint32) uint32 {
    25  	return (minor & 0xff) | ((uint32(major) & 0xfff) << 8) | ((minor >> 8) << 20)
    26  }
    27  
    28  // DecodeDeviceID decodes a device ID into major and minor device numbers.
    29  func DecodeDeviceID(rdev uint32) (uint16, uint32) {
    30  	major := uint16((rdev >> 8) & 0xfff)
    31  	minor := (rdev & 0xff) | ((rdev >> 20) << 8)
    32  	return major, minor
    33  }
    34  
    35  // Character device IDs.
    36  //
    37  // See Documentations/devices.txt and uapi/linux/major.h.
    38  const (
    39  	// UNNAMED_MAJOR is the major device number for "unnamed" devices, whose
    40  	// minor numbers are dynamically allocated by the kernel.
    41  	UNNAMED_MAJOR = 0
    42  
    43  	// MEM_MAJOR is the major device number for "memory" character devices.
    44  	MEM_MAJOR = 1
    45  
    46  	// TTYAUX_MAJOR is the major device number for alternate TTY devices.
    47  	TTYAUX_MAJOR = 5
    48  
    49  	// MISC_MAJOR is the major device number for non-serial mice, misc feature
    50  	// devices.
    51  	MISC_MAJOR = 10
    52  
    53  	// UNIX98_PTY_MASTER_MAJOR is the initial major device number for
    54  	// Unix98 PTY masters.
    55  	UNIX98_PTY_MASTER_MAJOR = 128
    56  
    57  	// UNIX98_PTY_REPLICA_MAJOR is the initial major device number for
    58  	// Unix98 PTY replicas.
    59  	UNIX98_PTY_REPLICA_MAJOR = 136
    60  )
    61  
    62  // Minor device numbers for TTYAUX_MAJOR.
    63  const (
    64  	// PTMX_MINOR is the minor device number for /dev/ptmx.
    65  	PTMX_MINOR = 2
    66  )
    67  
    68  // from Linux include/drm/drm_accel.h
    69  const (
    70  	// ACCEL_MAJOR is the major device number for compute accelerator devices.
    71  	ACCEL_MAJOR = 121
    72  )
    73  
    74  // Major device numbers for VFIO-based TPU.
    75  const (
    76  	// Major devices number between 243 and 254 are usually reserved for local use.
    77  	// The device number 245 is used by VFIO based TPU in GCP.
    78  	VFIO_MAJOR = 245
    79  )