mirror of
https://github.com/netbirdio/gvisor.git
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66 lines
1.8 KiB
Go
66 lines
1.8 KiB
Go
// Copyright 2020 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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//go:build arm64
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// +build arm64
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package fpu
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const (
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// fpsimdMagic is the magic number which is used in fpsimd_context.
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fpsimdMagic = 0x46508001
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// fpsimdContextSize is the size of fpsimd_context.
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fpsimdContextSize = 0x210
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)
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// initAarch64FPState sets up initial state.
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//
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// Related code in Linux kernel: fpsimd_flush_thread().
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// FPCR = FPCR_RM_RN (0x0 << 22).
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//
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// Currently, aarch64FPState is only a space of 0x210 length for fpstate.
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// The fp head is useless in sentry/ptrace/kvm.
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func initAarch64FPState(data *State) {
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}
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func newAarch64FPStateSlice() []byte {
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return alignedBytes(4096, 16)[:fpsimdContextSize]
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}
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// NewState returns an initialized floating point state.
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//
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// The returned state is large enough to store all floating point state
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// supported by host, even if the app won't use much of it due to a restricted
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// FeatureSet.
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func NewState() State {
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f := State(newAarch64FPStateSlice())
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initAarch64FPState(&f)
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return f
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}
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// Fork creates and returns an identical copy of the aarch64 floating point state.
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func (s *State) Fork() State {
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n := State(newAarch64FPStateSlice())
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copy(n, *s)
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return n
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}
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// BytePointer returns a pointer to the first byte of the state.
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//
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//go:nosplit
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func (s *State) BytePointer() *byte {
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return &(*s)[0]
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}
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