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Adin ScannellandgVisor bot daafc82dd5 Add explicit NOFRAME annotation in assembly functions.
For all trivial and zero frame-sized functions, we now require an explicit
NOFRAME annotation as the heuristic has changed. See go.dev/cl/466316.

Most of these functions do not  *require* NOFRAME, but this change encodes
the existing behavior in order to avoid accidental bugs or regressions.

PiperOrigin-RevId: 513946210
2023-03-04 00:53:20 -08:00

25 lines
910 B
ArmAsm

// 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 "textflag.h"
// func GetCPU() uint32
TEXT ·GetCPU(SB),NOSPLIT|NOFRAME,$0-4
BYTE $0x0f; BYTE $0x01; BYTE $0xf9; // RDTSCP
// On Linux, the bottom 12 bits of IA32_TSC_AUX are CPU and the upper 20
// are node. See arch/x86/entry/vdso/vma.c:vgetcpu_cpu_init().
ANDL $0xfff, CX
MOVL CX, ret+0(FP)
RET