mirror of
https://github.com/NVIDIA/nvidia-container-toolkit
synced 2024-12-02 00:54:48 +00:00
128 lines
2.8 KiB
Go
128 lines
2.8 KiB
Go
/*
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* Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package mmio
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import (
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"fmt"
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"os"
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"syscall"
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"unsafe"
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"github.com/NVIDIA/go-nvlib/pkg/nvpci/bytes"
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)
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// Mmio memory map a region.
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type Mmio interface {
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bytes.Raw
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bytes.Reader
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bytes.Writer
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Sync() error
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Close() error
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Slice(offset int, size int) Mmio
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LittleEndian() Mmio
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BigEndian() Mmio
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}
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type mmio struct {
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bytes.Bytes
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}
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func open(path string, offset int, size int, flags int) (Mmio, error) {
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var mmapFlags int
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switch flags {
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case os.O_RDONLY:
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mmapFlags = syscall.PROT_READ
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case os.O_RDWR:
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mmapFlags = syscall.PROT_READ | syscall.PROT_WRITE
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default:
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return nil, fmt.Errorf("invalid flags: %v", flags)
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}
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file, err := os.OpenFile(path, flags, 0)
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if err != nil {
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return nil, fmt.Errorf("failed to open file: %v", err)
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}
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defer file.Close()
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fi, err := file.Stat()
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if err != nil {
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return nil, fmt.Errorf("failed to get file info: %v", err)
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}
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if size > int(fi.Size()) {
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return nil, fmt.Errorf("requested size larger than file size")
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}
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if size < 0 {
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size = int(fi.Size())
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}
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mmap, err := syscall.Mmap(
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int(file.Fd()),
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int64(offset),
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size,
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mmapFlags,
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syscall.MAP_SHARED)
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if err != nil {
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return nil, fmt.Errorf("failed to mmap file: %v", err)
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}
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return &mmio{bytes.New(&mmap)}, nil
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}
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// OpenRO open region readonly.
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func OpenRO(path string, offset int, size int) (Mmio, error) {
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return open(path, offset, size, os.O_RDONLY)
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}
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// OpenRW open region read write.
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func OpenRW(path string, offset int, size int) (Mmio, error) {
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return open(path, offset, size, os.O_RDWR)
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}
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func (m *mmio) Slice(offset int, size int) Mmio {
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return &mmio{m.Bytes.Slice(offset, size)}
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}
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func (m *mmio) LittleEndian() Mmio {
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return &mmio{m.Bytes.LittleEndian()}
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}
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func (m *mmio) BigEndian() Mmio {
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return &mmio{m.Bytes.BigEndian()}
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}
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func (m *mmio) Close() error {
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err := syscall.Munmap(*m.Bytes.Raw())
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if err != nil {
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return fmt.Errorf("failed to munmap file: %v", err)
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}
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return nil
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}
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func (m *mmio) Sync() error {
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_, _, errno := syscall.Syscall(
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syscall.SYS_MSYNC,
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uintptr(unsafe.Pointer(&(*m.Bytes.Raw())[0])),
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uintptr(m.Len()),
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uintptr(syscall.MS_SYNC|syscall.MS_INVALIDATE))
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if errno != 0 {
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return fmt.Errorf("failed to msync file: %v", errno)
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}
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return nil
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}
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