mirror of
https://github.com/golang/go
synced 2024-11-20 08:44:39 -07:00
532dee3842
Signal handlers are global resources but many language environments (Go, C++ at Google, etc) assume they have sole ownership of a particular handler. Signal handlers in mixed-language applications must therefore be robust against unexpected delivery of certain signals, such as SIGPROF. The default Go signal handler runtime·sigtramp assumes that it will never be called on a non-Go thread, but this assumption is violated by when linking in C++ code that spawns threads. Specifically, the handler asserts the thread has an associated "m" (Go scheduler). This CL is a very simple workaround: discard SIGPROF delivered to non-Go threads. runtime.badsignal(int32) now receives the signal number; if it returns without panicking (e.g. sig==SIGPROF) the signal is discarded. I don't think there is any really satisfactory solution to the problem of signal-based profiling in a mixed-language application. It's not only the issue of handler clobbering, but also that a C++ SIGPROF handler called in a Go thread can't unwind the Go stack (and vice versa). The best we can hope for is not crashing. Note: - I've ported this to all POSIX platforms, except ARM-linux which already ignores unexpected signals on m-less threads. - I've avoided tail-calling runtime.badsignal because AFAICT the 6a/6l don't support it. - I've avoided hoisting 'push sig' (common to both function calls) because it makes the code harder to read. - Fixed an (apparently incorrect?) docstring. R=iant, rsc, minux.ma CC=golang-dev https://golang.org/cl/6498057
323 lines
5.5 KiB
ArmAsm
323 lines
5.5 KiB
ArmAsm
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//
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// System calls and other sys.stuff for AMD64, Linux
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//
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#include "zasm_GOOS_GOARCH.h"
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TEXT runtime·exit(SB),7,$0-8
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MOVL 8(SP), DI
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MOVL $231, AX // exitgroup - force all os threads to exit
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SYSCALL
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RET
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TEXT runtime·exit1(SB),7,$0-8
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MOVL 8(SP), DI
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MOVL $60, AX // exit - exit the current os thread
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SYSCALL
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RET
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TEXT runtime·open(SB),7,$0-16
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MOVQ 8(SP), DI
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MOVL 16(SP), SI
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MOVL 20(SP), DX
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MOVL $2, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·close(SB),7,$0-16
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MOVL 8(SP), DI
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MOVL $3, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·write(SB),7,$0-24
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVL 24(SP), DX
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MOVL $1, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·read(SB),7,$0-24
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVL 24(SP), DX
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MOVL $0, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·getrlimit(SB),7,$0-24
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVL $97, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·usleep(SB),7,$16
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MOVL $0, DX
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MOVL usec+0(FP), AX
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MOVL $1000000, CX
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DIVL CX
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MOVQ AX, 0(SP)
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MOVQ DX, 8(SP)
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// select(0, 0, 0, 0, &tv)
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MOVL $0, DI
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MOVL $0, SI
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MOVL $0, DX
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MOVL $0, R10
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MOVQ SP, R8
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MOVL $23, AX
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SYSCALL
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RET
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TEXT runtime·raisesigpipe(SB),7,$12
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MOVL $186, AX // syscall - gettid
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SYSCALL
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MOVL AX, DI // arg 1 tid
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MOVL $13, SI // arg 2 SIGPIPE
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MOVL $200, AX // syscall - tkill
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SYSCALL
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RET
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TEXT runtime·setitimer(SB),7,$0-24
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ 24(SP), DX
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MOVL $38, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·mincore(SB),7,$0-24
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MOVQ 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ 24(SP), DX
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MOVL $27, AX // syscall entry
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SYSCALL
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RET
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// func now() (sec int64, nsec int32)
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TEXT time·now(SB), 7, $32
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LEAQ 8(SP), DI
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MOVQ $0, SI
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MOVQ $0xffffffffff600000, AX
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CALL AX
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MOVQ 8(SP), AX // sec
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MOVL 16(SP), DX // usec
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// sec is in AX, usec in DX
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MOVQ AX, sec+0(FP)
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IMULQ $1000, DX
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MOVL DX, nsec+8(FP)
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RET
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TEXT runtime·nanotime(SB), 7, $32
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LEAQ 8(SP), DI
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MOVQ $0, SI
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MOVQ $0xffffffffff600000, AX
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CALL AX
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MOVQ 8(SP), AX // sec
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MOVL 16(SP), DX // usec
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// sec is in AX, usec in DX
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// return nsec in AX
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IMULQ $1000000000, AX
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IMULQ $1000, DX
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ADDQ DX, AX
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RET
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TEXT runtime·rtsigprocmask(SB),7,$0-32
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ 24(SP), DX
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MOVL 32(SP), R10
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MOVL $14, AX // syscall entry
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 2(PC)
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MOVL $0xf1, 0xf1 // crash
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RET
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TEXT runtime·rt_sigaction(SB),7,$0-32
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MOVL 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ 24(SP), DX
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MOVQ 32(SP), R10
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MOVL $13, AX // syscall entry
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SYSCALL
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RET
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TEXT runtime·sigtramp(SB),7,$64
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get_tls(BX)
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// check that m exists
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MOVQ m(BX), BP
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CMPQ BP, $0
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JNE 4(PC)
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MOVQ DI, 0(SP)
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CALL runtime·badsignal(SB)
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RET
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// save g
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MOVQ g(BX), R10
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MOVQ R10, 40(SP)
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// g = m->gsignal
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MOVQ m_gsignal(BP), BP
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MOVQ BP, g(BX)
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MOVQ DI, 0(SP)
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MOVQ SI, 8(SP)
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MOVQ DX, 16(SP)
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MOVQ R10, 24(SP)
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CALL runtime·sighandler(SB)
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// restore g
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get_tls(BX)
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MOVQ 40(SP), R10
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MOVQ R10, g(BX)
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RET
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TEXT runtime·sigreturn(SB),7,$0
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MOVL $15, AX // rt_sigreturn
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SYSCALL
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INT $3 // not reached
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TEXT runtime·mmap(SB),7,$0
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MOVQ 8(SP), DI
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MOVQ $0, SI
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MOVQ 16(SP), SI
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MOVL 24(SP), DX
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MOVL 28(SP), R10
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MOVL 32(SP), R8
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MOVL 36(SP), R9
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MOVL $9, AX // mmap
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 3(PC)
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NOTQ AX
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INCQ AX
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RET
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TEXT runtime·munmap(SB),7,$0
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MOVQ 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ $11, AX // munmap
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 2(PC)
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MOVL $0xf1, 0xf1 // crash
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RET
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TEXT runtime·madvise(SB),7,$0
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MOVQ 8(SP), DI
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MOVQ 16(SP), SI
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MOVQ 24(SP), DX
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MOVQ $28, AX // madvise
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 2(PC)
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MOVL $0xf1, 0xf1 // crash
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RET
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// int64 futex(int32 *uaddr, int32 op, int32 val,
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// struct timespec *timeout, int32 *uaddr2, int32 val2);
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TEXT runtime·futex(SB),7,$0
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MOVQ 8(SP), DI
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MOVL 16(SP), SI
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MOVL 20(SP), DX
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MOVQ 24(SP), R10
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MOVQ 32(SP), R8
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MOVL 40(SP), R9
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MOVL $202, AX
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SYSCALL
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RET
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// int64 clone(int32 flags, void *stack, M *m, G *g, void (*fn)(void));
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TEXT runtime·clone(SB),7,$0
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MOVL flags+8(SP), DI
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MOVQ stack+16(SP), SI
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// Copy m, g, fn off parent stack for use by child.
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// Careful: Linux system call clobbers CX and R11.
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MOVQ mm+24(SP), R8
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MOVQ gg+32(SP), R9
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MOVQ fn+40(SP), R12
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MOVL $56, AX
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SYSCALL
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// In parent, return.
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CMPQ AX, $0
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JEQ 2(PC)
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RET
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// In child, on new stack.
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MOVQ SI, SP
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// Initialize m->procid to Linux tid
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MOVL $186, AX // gettid
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SYSCALL
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MOVQ AX, m_procid(R8)
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// Set FS to point at m->tls.
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LEAQ m_tls(R8), DI
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CALL runtime·settls(SB)
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// In child, set up new stack
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get_tls(CX)
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MOVQ R8, m(CX)
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MOVQ R9, g(CX)
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CALL runtime·stackcheck(SB)
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// Call fn
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CALL R12
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// It shouldn't return. If it does, exit
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MOVL $111, DI
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MOVL $60, AX
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SYSCALL
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JMP -3(PC) // keep exiting
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TEXT runtime·sigaltstack(SB),7,$-8
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MOVQ new+8(SP), DI
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MOVQ old+16(SP), SI
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MOVQ $131, AX
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 2(PC)
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MOVL $0xf1, 0xf1 // crash
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RET
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// set tls base to DI
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TEXT runtime·settls(SB),7,$32
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ADDQ $16, DI // ELF wants to use -16(FS), -8(FS)
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MOVQ DI, SI
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MOVQ $0x1002, DI // ARCH_SET_FS
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MOVQ $158, AX // arch_prctl
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SYSCALL
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CMPQ AX, $0xfffffffffffff001
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JLS 2(PC)
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MOVL $0xf1, 0xf1 // crash
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RET
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TEXT runtime·osyield(SB),7,$0
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MOVL $24, AX
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SYSCALL
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RET
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TEXT runtime·sched_getaffinity(SB),7,$0
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MOVQ 8(SP), DI
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MOVL 16(SP), SI
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MOVQ 24(SP), DX
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MOVL $204, AX // syscall entry
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SYSCALL
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RET
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