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// Copyright 2019 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 arm64
// +build arm64
package kvm
import (
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/ring0"
"gvisor.dev/gvisor/pkg/sentry/arch"
)
var (
// The action for bluepillSignal is changed by sigaction().
bluepillSignal = unix.SIGILL
)
// getTLS returns the value of TPIDR_EL0 register.
//
//go:nosplit
func getTLS() (value uint64)
// setTLS writes the TPIDR_EL0 value.
//
//go:nosplit
func setTLS(value uint64)
// bluepillArchEnter is called during bluepillEnter.
//
//go:nosplit
func bluepillArchEnter(context *arch.SignalContext64) (c *vCPU) {
c = vCPUPtr(uintptr(context.Regs[8]))
regs := c.CPU.Registers()
regs.Regs = context.Regs
regs.Sp = context.Sp
regs.Pc = context.Pc
regs.Pstate = context.Pstate
regs.Pstate &^= uint64(ring0.PsrFlagsClear)
regs.Pstate |= ring0.KernelFlagsSet
regs.TPIDR_EL0 = getTLS()
return
}
// bluepillArchExit is called during bluepillEnter.
//
//go:nosplit
func bluepillArchExit(c *vCPU, context *arch.SignalContext64) {
regs := c.CPU.Registers()
context.Regs = regs.Regs
context.Sp = regs.Sp
context.Pc = regs.Pc
context.Pstate = regs.Pstate
context.Pstate &^= uint64(ring0.PsrFlagsClear)
context.Pstate |= ring0.UserFlagsSet
setTLS(regs.TPIDR_EL0)
lazyVfp := c.GetLazyVFP()
if lazyVfp != 0 {
fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
context.Fpsimd64.Fpsr = fpsimd.Fpsr
context.Fpsimd64.Fpcr = fpsimd.Fpcr
context.Fpsimd64.Vregs = fpsimd.Vregs
}
}
// KernelSyscall handles kernel syscalls.
//
// +checkescape:all
//
//go:nosplit
func (c *vCPU) KernelSyscall() {
regs := c.Registers()
if regs.Regs[8] != ^uint64(0) {
regs.Pc -= 4 // Rewind.
}
fpDisableTrap := ring0.CPACREL1()
if fpDisableTrap != 0 {
fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
fpcr := ring0.GetFPCR()
fpsr := ring0.GetFPSR()
fpsimd.Fpcr = uint32(fpcr)
fpsimd.Fpsr = uint32(fpsr)
ring0.SaveVRegs(c.FloatingPointState().BytePointer()) // escapes: no
}
ring0.Halt()
}
// KernelException handles kernel exceptions.
//
// +checkescape:all
//
//go:nosplit
func (c *vCPU) KernelException(vector ring0.Vector) {
regs := c.Registers()
if vector == ring0.Vector(bounce) {
regs.Pc = 0
}
fpDisableTrap := ring0.CPACREL1()
if fpDisableTrap != 0 {
fpsimd := fpsimdPtr(c.FloatingPointState().BytePointer()) // escapes: no
fpcr := ring0.GetFPCR()
fpsr := ring0.GetFPSR()
fpsimd.Fpcr = uint32(fpcr)
fpsimd.Fpsr = uint32(fpsr)
ring0.SaveVRegs(c.FloatingPointState().BytePointer()) // escapes: no
}
ring0.Halt()
}
// hltSanityCheck verifies the current state to detect obvious corruption.
//
//go:nosplit
func (c *vCPU) hltSanityCheck() {
}
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