mirror of
https://github.com/netbirdio/gvisor.git
synced 2026-05-22 17:12:49 -07:00
Konstantin Bogomolov
bb84006816
SETREGSET/GETREGSET expect AMX portions of fpstate to always be used. For this reason we need to allocate enough memory for this to happen, even if we never populate the AMX portions within initX86FPState. PiperOrigin-RevId: 599702181
85 lines
2.0 KiB
Go
85 lines
2.0 KiB
Go
// Copyright 2023 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 amd64
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// +build amd64
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package sysmsg
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import (
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_ "embed"
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"fmt"
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"strings"
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"gvisor.dev/gvisor/pkg/cpuid"
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)
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// SighandlerBlob contains the compiled code of the sysmsg signal handler.
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//
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//go:embed sighandler.built-in.amd64.bin
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var SighandlerBlob []byte
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// ArchState defines variables specific to the architecture being
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// used.
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type ArchState struct {
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xsaveMode uint32
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fpLen uint32
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fsgsbase uint32
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}
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// The linux kernel does not allow using xsavec from userspace, so we are limited
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// to xsaveopt.
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// See arch/x86/kernel/fpu/xstate.c:validate_user_xstate_header for details.
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const (
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fxsave = iota
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xsave
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xsaveopt
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)
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// Init initializes the arch specific state.
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func (s *ArchState) Init() {
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fs := cpuid.HostFeatureSet()
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fpLenUint, _ := fs.ExtendedStateSize()
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// TODO(gvisor.dev/issues/9896): Implement AMX Support.
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s.fpLen = uint32(fpLenUint - fs.AMXExtendedStateSize())
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if fs.UseXsaveopt() {
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s.xsaveMode = xsaveopt
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} else if fs.UseXsave() {
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s.xsaveMode = xsave
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} else {
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s.xsaveMode = fxsave
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}
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if fs.UseFSGSBASE() {
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s.fsgsbase = 1
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}
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}
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// FpLen returns the FP state length for AMD64.
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func (s *ArchState) FpLen() int {
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return int(s.fpLen)
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}
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func (s *ArchState) String() string {
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var b strings.Builder
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fmt.Fprintf(&b, "sysmsg.ArchState{")
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fmt.Fprintf(&b, " xsaveMode %d", s.xsaveMode)
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fmt.Fprintf(&b, " fsgsbase %d", s.fsgsbase)
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fmt.Fprintf(&b, " fpLen %d", s.fpLen)
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b.WriteString(" }")
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return b.String()
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}
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