github.com/metacubex/gvisor@v0.0.0-20240320004321-933faba989ec/pkg/sentry/hostcpu/getcpu_arm64.s (about)

     1  // Copyright 2019 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  #include "textflag.h"
    16  
    17  // GetCPU makes the getcpu(unsigned *cpu, unsigned *node, NULL) syscall for
    18  // the lack of an optimazed way of getting the current CPU number on arm64.
    19  
    20  // func GetCPU() uint32
    21  TEXT ·GetCPU(SB), NOSPLIT, $0-4
    22  	MOVW ZR, ret+0(FP)
    23  	MOVD $ret+0(FP), R0
    24  	MOVD $0x0, R1  // unused
    25  	MOVD $0x0, R2  // unused
    26  	MOVD $0xA8, R8 // SYS_GETCPU
    27  	SVC
    28  	RET