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// Copyright 2023 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build amd64
// +build amd64
package sysmsg
import (
_ "embed"
"fmt"
"strings"
"gvisor.dev/gvisor/pkg/cpuid"
)
// SighandlerBlob contains the compiled code of the sysmsg signal handler.
//
//go:embed sighandler.built-in.amd64.bin
var SighandlerBlob []byte
// ArchState defines variables specific to the architecture being
// used.
type ArchState struct {
xsaveMode uint32
fpLen uint32
fsgsbase uint32
}
// The linux kernel does not allow using xsavec from userspace, so we are limited
// to xsaveopt.
// See arch/x86/kernel/fpu/xstate.c:validate_user_xstate_header for details.
const (
fxsave = iota
xsave
xsaveopt
)
// Init initializes the arch specific state.
func (s *ArchState) Init() {
fs := cpuid.HostFeatureSet()
fpLenUint, _ := fs.ExtendedStateSize()
// TODO(gvisor.dev/issues/9896): Implement AMX Support.
s.fpLen = uint32(fpLenUint - fs.AMXExtendedStateSize())
if fs.UseXsaveopt() {
s.xsaveMode = xsaveopt
} else if fs.UseXsave() {
s.xsaveMode = xsave
} else {
s.xsaveMode = fxsave
}
if fs.UseFSGSBASE() {
s.fsgsbase = 1
}
}
// FpLen returns the FP state length for AMD64.
func (s *ArchState) FpLen() int {
return int(s.fpLen)
}
func (s *ArchState) String() string {
var b strings.Builder
fmt.Fprintf(&b, "sysmsg.ArchState{")
fmt.Fprintf(&b, " xsaveMode %d", s.xsaveMode)
fmt.Fprintf(&b, " fsgsbase %d", s.fsgsbase)
fmt.Fprintf(&b, " fpLen %d", s.fpLen)
b.WriteString(" }")
return b.String()
}
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