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125 lines
3.0 KiB
125 lines
3.0 KiB
/*
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* Copyright 2021 ByteDance Inc.
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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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*/
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package rt
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import (
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`os`
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`sync/atomic`
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`unsafe`
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`golang.org/x/arch/x86/x86asm`
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)
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const (
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_MaxInstr = 15
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)
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func isvar(arg x86asm.Arg) bool {
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v, ok := arg.(x86asm.Mem)
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return ok && v.Base == x86asm.RIP
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}
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func iszero(arg x86asm.Arg) bool {
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v, ok := arg.(x86asm.Imm)
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return ok && v == 0
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}
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func GcwbAddr() uintptr {
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var err error
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var off uintptr
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var ins x86asm.Inst
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/* get the function address */
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pc := uintptr(0)
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fp := FuncAddr(atomic.StorePointer)
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/* search within the first 16 instructions */
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for i := 0; i < 16; i++ {
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mem := unsafe.Pointer(uintptr(fp) + pc)
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buf := BytesFrom(mem, _MaxInstr, _MaxInstr)
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/* disassemble the instruction */
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if ins, err = x86asm.Decode(buf, 64); err != nil {
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panic("gcwbaddr: " + err.Error())
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}
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/* check for a byte comparison with zero */
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if ins.Op == x86asm.CMP && ins.MemBytes == 1 && isvar(ins.Args[0]) && iszero(ins.Args[1]) {
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off = pc + uintptr(ins.Len) + uintptr(ins.Args[0].(x86asm.Mem).Disp)
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break
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}
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/* move to next instruction */
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nb := ins.Len
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pc += uintptr(nb)
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}
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/* check for address */
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if off == 0 {
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panic("gcwbaddr: could not locate the variable `writeBarrier`")
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} else {
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return uintptr(fp) + off
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}
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}
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// StopProfiling is used to stop traceback introduced by SIGPROF while native code is running.
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// WARN: this option is only a workaround for traceback issue (https://github.com/bytedance/sonic/issues/310),
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// and will be dropped when the issue is fixed.
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var StopProfiling = os.Getenv("SONIC_STOP_PROFILING") != ""
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// WARN: must be aligned with runtime.Prof
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// type Prof struct {
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// signalLock uint32
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// hz int32
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// }
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var (
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// // go:linkname runtimeProf runtime.prof
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// runtimeProf Prof
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// count of native-C calls
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yieldCount uint32
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// previous value of runtimeProf.hz
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oldHz int32
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)
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//go:nosplit
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func MoreStack(size uintptr)
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func StopProf()
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// func StopProf() {
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// atomic.AddUint32(&yieldCount, 1)
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// if runtimeProf.hz != 0 {
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// oldHz = runtimeProf.hz
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// runtimeProf.hz = 0
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// }
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// }
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func StartProf()
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// func StartProf() {
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// atomic.AddUint32(&yieldCount, ^uint32(0))
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// if yieldCount == 0 && runtimeProf.hz == 0 {
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// if oldHz == 0 {
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// oldHz = 100
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// }
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// runtimeProf.hz = oldHz
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// }
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// }
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