gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/pkg/sentry/platform/ptrace/ptrace_amd64.go (about)

     1  // Copyright 2019 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //go:build amd64
    16  // +build amd64
    17  
    18  package ptrace
    19  
    20  import (
    21  	"gvisor.dev/gvisor/pkg/abi/linux"
    22  	pkgcontext "gvisor.dev/gvisor/pkg/context"
    23  	"gvisor.dev/gvisor/pkg/cpuid"
    24  	"gvisor.dev/gvisor/pkg/sentry/arch"
    25  )
    26  
    27  // archContext is architecture-specific context.
    28  type archContext struct {
    29  	// fpLen is the size of the floating point state.
    30  	fpLen int
    31  
    32  	// useXsave indicates whether or not xsave is in use.
    33  	useXsave bool
    34  }
    35  
    36  // init initializes the archContext.
    37  func (a *archContext) init(ctx pkgcontext.Context) {
    38  	fs := cpuid.FromContext(ctx)
    39  	fpLen, _ := fs.ExtendedStateSize()
    40  	useXsave := fs.UseXsave()
    41  	a.fpLen = int(fpLen)
    42  	a.useXsave = useXsave
    43  }
    44  
    45  // floatingPointLength returns the length of floating point state.
    46  func (a *archContext) floatingPointLength() uint64 {
    47  	return uint64(a.fpLen)
    48  }
    49  
    50  // floatingPointRegSet returns the register set to fetch.
    51  func (a *archContext) floatingPointRegSet() uintptr {
    52  	if a.useXsave {
    53  		return linux.NT_X86_XSTATE
    54  	}
    55  	return linux.NT_PRFPREG
    56  }
    57  
    58  func stackPointer(r *arch.Registers) uintptr {
    59  	return uintptr(r.Rsp)
    60  }
    61  
    62  // x86 use the fs_base register to store the TLS pointer which can be
    63  // get/set in "func (t *thread) get/setRegs(regs *arch.Registers)".
    64  // So both of the get/setTLS() operations are noop here.
    65  
    66  // getTLS gets the thread local storage register.
    67  func (t *thread) getTLS(tls *uint64) error {
    68  	return nil
    69  }
    70  
    71  // setTLS sets the thread local storage register.
    72  func (t *thread) setTLS(tls *uint64) error {
    73  	return nil
    74  }