88 lines
2.2 KiB
ArmAsm
88 lines
2.2 KiB
ArmAsm
// Copyright 2019 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "textflag.h"
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// VCPU_CPU is the location of the CPU in the vCPU struct.
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//
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// This is guaranteed to be zero.
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#define VCPU_CPU 0x0
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// CPU_SELF is the self reference in ring0's percpu.
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//
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// This is guaranteed to be zero.
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#define CPU_SELF 0x0
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// Context offsets.
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//
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// Only limited use of the context is done in the assembly stub below, most is
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// done in the Go handlers.
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#define SIGINFO_SIGNO 0x0
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#define CONTEXT_PC 0x1B8
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#define CONTEXT_R0 0xB8
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// See bluepill.go.
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TEXT ·bluepill(SB),NOSPLIT,$0
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begin:
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MOVD vcpu+0(FP), R8
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MOVD $VCPU_CPU(R8), R9
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ORR $0xffff000000000000, R9, R9
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// Trigger sigill.
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// In ring0.Start(), the value of R8 will be stored into tpidr_el1.
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// When the context was loaded into vcpu successfully,
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// we will check if the value of R10 and R9 are the same.
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WORD $0xd538d08a // MRS TPIDR_EL1, R10
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check_vcpu:
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CMP R10, R9
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BEQ right_vCPU
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wrong_vcpu:
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CALL ·redpill(SB)
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B begin
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right_vCPU:
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RET
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// sighandler: see bluepill.go for documentation.
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//
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// The arguments are the following:
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//
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// R0 - The signal number.
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// R1 - Pointer to siginfo_t structure.
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// R2 - Pointer to ucontext structure.
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//
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TEXT ·sighandler(SB),NOSPLIT,$0
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// si_signo should be sigill.
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MOVD SIGINFO_SIGNO(R1), R7
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CMPW $4, R7
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BNE fallback
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MOVD CONTEXT_PC(R2), R7
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CMPW $0, R7
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BEQ fallback
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MOVD R2, 8(RSP)
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BL ·bluepillHandler(SB) // Call the handler.
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RET
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fallback:
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// Jump to the previous signal handler.
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MOVD ·savedHandler(SB), R7
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B (R7)
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// dieTrampoline: see bluepill.go, bluepill_arm64_unsafe.go for documentation.
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TEXT ·dieTrampoline(SB),NOSPLIT,$0
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// TODO(gvisor.dev/issue/1249): dieTrampoline supporting for Arm64.
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MOVD R9, 8(RSP)
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BL ·dieHandler(SB)
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