67 lines
2.1 KiB
Go
67 lines
2.1 KiB
Go
// Copyright 2018 The gVisor Authors.
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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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// +build linux,amd64 linux,arm64
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// +build go1.12
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// +build !go1.15
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// Check go:linkname function signatures when updating Go version.
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package rawfile
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import (
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"syscall"
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_ "unsafe" // for go:linkname
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)
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// BlockingPoll on amd64/arm64 makes the ppoll() syscall while calling the
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// version of entersyscall that relinquishes the P so that other Gs can
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// run. This is meant to be called in cases when the syscall is expected to
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// block. On non amd64/arm64 platforms it just forwards to the ppoll() system
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// call.
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//
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//go:noescape
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func BlockingPoll(fds *PollEvent, nfds int, timeout *syscall.Timespec) (int, syscall.Errno)
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// Use go:linkname to call into the runtime. As of Go 1.12 this has to
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// be done from Go code so that we make an ABIInternal call to an
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// ABIInternal function; see https://golang.org/issue/27539.
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// We need to call both entersyscallblock and exitsyscall this way so
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// that the runtime's check on the stack pointer lines up.
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// Note that calling an unexported function in the runtime package is
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// unsafe and this hack is likely to break in future Go releases.
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//go:linkname entersyscallblock runtime.entersyscallblock
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func entersyscallblock()
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//go:linkname exitsyscall runtime.exitsyscall
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func exitsyscall()
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// These forwarding functions must be nosplit because 1) we must
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// disallow preemption between entersyscallblock and exitsyscall, and
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// 2) we have an untyped assembly frame on the stack which can not be
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// grown or moved.
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//go:nosplit
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func callEntersyscallblock() {
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entersyscallblock()
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}
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//go:nosplit
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func callExitsyscall() {
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exitsyscall()
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}
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