102 lines
2.6 KiB
ArmAsm
102 lines
2.6 KiB
ArmAsm
// 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.
|
|
|
|
#include "textflag.h"
|
|
|
|
// VCPU_CPU is the location of the CPU in the vCPU struct.
|
|
//
|
|
// This is guaranteed to be zero.
|
|
#define VCPU_CPU 0x0
|
|
|
|
// CPU_SELF is the self reference in ring0's percpu.
|
|
//
|
|
// This is guaranteed to be zero.
|
|
#define CPU_SELF 0x0
|
|
|
|
// Context offsets.
|
|
//
|
|
// Only limited use of the context is done in the assembly stub below, most is
|
|
// done in the Go handlers.
|
|
#define SIGINFO_SIGNO 0x0
|
|
#define CONTEXT_PC 0x1B8
|
|
#define CONTEXT_R0 0xB8
|
|
|
|
// getTLS returns the value of TPIDR_EL0 register.
|
|
TEXT ·getTLS(SB),NOSPLIT,$0-8
|
|
MRS TPIDR_EL0, R1
|
|
MOVD R1, ret+0(FP)
|
|
RET
|
|
|
|
// setTLS writes the TPIDR_EL0 value.
|
|
TEXT ·setTLS(SB),NOSPLIT,$0-8
|
|
MOVD addr+0(FP), R1
|
|
MSR R1, TPIDR_EL0
|
|
RET
|
|
|
|
// See bluepill.go.
|
|
TEXT ·bluepill(SB),NOSPLIT,$0
|
|
begin:
|
|
MOVD vcpu+0(FP), R8
|
|
MOVD $VCPU_CPU(R8), R9
|
|
ORR $0xffff000000000000, R9, R9
|
|
// Trigger sigill.
|
|
// In ring0.Start(), the value of R8 will be stored into tpidr_el1.
|
|
// When the context was loaded into vcpu successfully,
|
|
// we will check if the value of R10 and R9 are the same.
|
|
WORD $0xd538d08a // MRS TPIDR_EL1, R10
|
|
check_vcpu:
|
|
CMP R10, R9
|
|
BEQ right_vCPU
|
|
wrong_vcpu:
|
|
CALL ·redpill(SB)
|
|
B begin
|
|
right_vCPU:
|
|
RET
|
|
|
|
// sighandler: see bluepill.go for documentation.
|
|
//
|
|
// The arguments are the following:
|
|
//
|
|
// R0 - The signal number.
|
|
// R1 - Pointer to siginfo_t structure.
|
|
// R2 - Pointer to ucontext structure.
|
|
//
|
|
TEXT ·sighandler(SB),NOSPLIT,$0
|
|
// si_signo should be sigill.
|
|
MOVD SIGINFO_SIGNO(R1), R7
|
|
CMPW $4, R7
|
|
BNE fallback
|
|
|
|
MOVD CONTEXT_PC(R2), R7
|
|
CMPW $0, R7
|
|
BEQ fallback
|
|
|
|
MOVD R2, 8(RSP)
|
|
BL ·bluepillHandler(SB) // Call the handler.
|
|
|
|
RET
|
|
|
|
fallback:
|
|
// Jump to the previous signal handler.
|
|
MOVD ·savedHandler(SB), R7
|
|
B (R7)
|
|
|
|
// dieTrampoline: see bluepill.go, bluepill_arm64_unsafe.go for documentation.
|
|
TEXT ·dieTrampoline(SB),NOSPLIT,$0
|
|
// R0: Fake the old PC as caller
|
|
// R1: First argument (vCPU)
|
|
MOVD.P R1, 8(RSP) // R1: First argument (vCPU)
|
|
MOVD.P R0, 8(RSP) // R0: Fake the old PC as caller
|
|
B ·dieHandler(SB)
|