2019-04-29 21:25:05 +00:00
|
|
|
// Copyright 2018 The gVisor Authors.
|
2018-04-27 17:37:02 +00:00
|
|
|
//
|
|
|
|
// 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. However, the RIP must be examined.
|
|
|
|
#define CONTEXT_RAX 0x90
|
|
|
|
#define CONTEXT_RIP 0xa8
|
|
|
|
#define CONTEXT_FP 0xe0
|
|
|
|
|
|
|
|
// CLI is the literal byte for the disable interrupts instruction.
|
|
|
|
//
|
|
|
|
// This is checked as the source of the fault.
|
|
|
|
#define CLI $0xfa
|
|
|
|
|
|
|
|
// See bluepill.go.
|
|
|
|
TEXT ·bluepill(SB),NOSPLIT,$0
|
|
|
|
begin:
|
|
|
|
MOVQ vcpu+0(FP), AX
|
|
|
|
LEAQ VCPU_CPU(AX), BX
|
|
|
|
BYTE CLI;
|
|
|
|
check_vcpu:
|
|
|
|
MOVQ CPU_SELF(GS), CX
|
|
|
|
CMPQ BX, CX
|
|
|
|
JE right_vCPU
|
|
|
|
wrong_vcpu:
|
|
|
|
CALL ·redpill(SB)
|
|
|
|
JMP begin
|
|
|
|
right_vCPU:
|
|
|
|
RET
|
|
|
|
|
|
|
|
// sighandler: see bluepill.go for documentation.
|
|
|
|
//
|
|
|
|
// The arguments are the following:
|
|
|
|
//
|
|
|
|
// DI - The signal number.
|
|
|
|
// SI - Pointer to siginfo_t structure.
|
|
|
|
// DX - Pointer to ucontext structure.
|
|
|
|
//
|
|
|
|
TEXT ·sighandler(SB),NOSPLIT,$0
|
|
|
|
// Check if the signal is from the kernel.
|
|
|
|
MOVQ $0x80, CX
|
|
|
|
CMPL CX, 0x8(SI)
|
|
|
|
JNE fallback
|
|
|
|
|
|
|
|
// Check if RIP is disable interrupts.
|
|
|
|
MOVQ CONTEXT_RIP(DX), CX
|
|
|
|
CMPQ CX, $0x0
|
|
|
|
JE fallback
|
|
|
|
CMPB 0(CX), CLI
|
|
|
|
JNE fallback
|
|
|
|
|
|
|
|
// Call the bluepillHandler.
|
|
|
|
PUSHQ DX // First argument (context).
|
|
|
|
CALL ·bluepillHandler(SB) // Call the handler.
|
|
|
|
POPQ DX // Discard the argument.
|
|
|
|
RET
|
|
|
|
|
|
|
|
fallback:
|
|
|
|
// Jump to the previous signal handler.
|
|
|
|
XORQ CX, CX
|
|
|
|
MOVQ ·savedHandler(SB), AX
|
|
|
|
JMP AX
|
2018-10-31 22:49:10 +00:00
|
|
|
|
|
|
|
// dieTrampoline: see bluepill.go, bluepill_amd64_unsafe.go for documentation.
|
|
|
|
TEXT ·dieTrampoline(SB),NOSPLIT,$0
|
|
|
|
PUSHQ BX // First argument (vCPU).
|
|
|
|
PUSHQ AX // Fake the old RIP as caller.
|
|
|
|
JMP ·dieHandler(SB)
|