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// Copyright 2018 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 "funcdata.h"
#include "textflag.h"
// fxrstor loads floating point state.
//
// The code corresponds to:
//
// fxrstor64 (%rbx)
//
TEXT ·fxrstor(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), BX
MOVL $0xffffffff, AX
MOVL $0xffffffff, DX
BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0x0b;
RET
// xrstor loads floating point state.
//
// The code corresponds to:
//
// xrstor (%rdi)
//
TEXT ·xrstor(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), DI
MOVL $0xffffffff, AX
MOVL $0xffffffff, DX
BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0x2f;
RET
// fxsave saves floating point state.
//
// The code corresponds to:
//
// fxsave64 (%rbx)
//
TEXT ·fxsave(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), BX
MOVL $0xffffffff, AX
MOVL $0xffffffff, DX
BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0x03;
RET
// xsave saves floating point state.
//
// The code corresponds to:
//
// xsave (%rdi)
//
TEXT ·xsave(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), DI
MOVL $0xffffffff, AX
MOVL $0xffffffff, DX
BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0x27;
RET
// xsaveopt saves floating point state.
//
// The code corresponds to:
//
// xsaveopt (%rdi)
//
TEXT ·xsaveopt(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), DI
MOVL $0xffffffff, AX
MOVL $0xffffffff, DX
BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0x37;
RET
// writeFS writes to the FS base.
//
// This is written in assembly because it must be safe to call before the Go
// environment is set up. See comment on start().
//
// Preconditions: must be running in the lower address space, as it accesses
// global data.
TEXT ·writeFS(SB),NOSPLIT,$8-8
MOVQ addr+0(FP), AX
CMPB ·hasFSGSBASE(SB), $1
JNE msr
PUSHQ AX
CALL ·wrfsbase(SB)
POPQ AX
RET
msr:
PUSHQ AX
CALL ·wrfsmsr(SB)
POPQ AX
RET
// wrfsbase writes to the FS base.
//
// The code corresponds to:
//
// wrfsbase %rax
//
TEXT ·wrfsbase(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), AX
BYTE $0xf3; BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0xd0;
RET
// wrfsmsr writes to the FSBASE MSR.
//
// The code corresponds to:
//
// wrmsr (writes EDX:EAX to the MSR in ECX)
//
TEXT ·wrfsmsr(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), AX
MOVQ AX, DX
SHRQ $32, DX
MOVQ $0xc0000100, CX // MSR_FS_BASE
BYTE $0x0f; BYTE $0x30;
RET
// writeGS writes to the GS base.
//
// This is written in assembly because it must be callable from assembly (ABI0)
// without an intermediate transition to ABIInternal.
//
// Preconditions: must be running in the lower address space, as it accesses
// global data.
TEXT ·writeGS(SB),NOSPLIT,$8-8
MOVQ addr+0(FP), AX
CMPB ·hasFSGSBASE(SB), $1
JNE msr
PUSHQ AX
CALL ·wrgsbase(SB)
POPQ AX
RET
msr:
PUSHQ AX
CALL ·wrgsmsr(SB)
POPQ AX
RET
// wrgsbase writes to the GS base.
//
// The code corresponds to:
//
// wrgsbase %rax
//
TEXT ·wrgsbase(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), AX
BYTE $0xf3; BYTE $0x48; BYTE $0x0f; BYTE $0xae; BYTE $0xd8;
RET
// wrgsmsr writes to the GSBASE MSR.
//
// See wrfsmsr.
TEXT ·wrgsmsr(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), AX
MOVQ AX, DX
SHRQ $32, DX
MOVQ $0xc0000101, CX // MSR_GS_BASE
BYTE $0x0f; BYTE $0x30; // WRMSR
RET
// readCR2 reads the current CR2 value.
//
// The code corresponds to:
//
// mov %cr2, %rax
//
TEXT ·readCR2(SB),NOSPLIT,$0-8
BYTE $0x0f; BYTE $0x20; BYTE $0xd0;
MOVQ AX, ret+0(FP)
RET
// fninit initializes the floating point unit.
//
// The code corresponds to:
//
// fninit
TEXT ·fninit(SB),NOSPLIT,$0
BYTE $0xdb; BYTE $0xe3;
RET
// xsetbv writes to an extended control register.
//
// The code corresponds to:
//
// xsetbv
//
TEXT ·xsetbv(SB),NOSPLIT,$0-16
MOVL reg+0(FP), CX
MOVL value+8(FP), AX
MOVL value+12(FP), DX
BYTE $0x0f; BYTE $0x01; BYTE $0xd1;
RET
// xgetbv reads an extended control register.
//
// The code corresponds to:
//
// xgetbv
//
TEXT ·xgetbv(SB),NOSPLIT,$0-16
MOVL reg+0(FP), CX
BYTE $0x0f; BYTE $0x01; BYTE $0xd0;
MOVL AX, ret+8(FP)
MOVL DX, ret+12(FP)
RET
// wrmsr writes to a control register.
//
// The code corresponds to:
//
// wrmsr
//
TEXT ·wrmsr(SB),NOSPLIT,$0-16
MOVL reg+0(FP), CX
MOVL value+8(FP), AX
MOVL value+12(FP), DX
BYTE $0x0f; BYTE $0x30;
RET
// rdmsr reads a control register.
//
// The code corresponds to:
//
// rdmsr
//
TEXT ·rdmsr(SB),NOSPLIT,$0-16
MOVL reg+0(FP), CX
BYTE $0x0f; BYTE $0x32;
MOVL AX, ret+8(FP)
MOVL DX, ret+12(FP)
RET
// stmxcsr reads the MXCSR control and status register.
TEXT ·stmxcsr(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), SI
STMXCSR (SI)
RET
// ldmxcsr writes to the MXCSR control and status register.
TEXT ·ldmxcsr(SB),NOSPLIT,$0-8
MOVQ addr+0(FP), SI
LDMXCSR (SI)
RET
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