mp := gp.m
	resetLibcall := true
	if mp.libcallsp == 0 {
		mp.libcallg.set(gp)
		mp.libcallpc = getcallerpc()
		// sp must be the last, because once async cpu profiler finds
		// all three values to be non-zero, it will use them
		mp.libcallsp = getcallersp()
	} else {
		resetLibcall = false // See comment in sys_darwin.go:libcCall
	}

	c := libcall{
		fn:   uintptr(unsafe.Pointer(fn)),
		n:    2,

	if resetLibcall {
		mp.libcallsp = 0
	}
	return mp.libcall.r1
}

//go:nosplit
func stdcall0(fn stdFunction) uintptr {
	mp := getg().m
	mp.libcall.n = 0
	mp.libcall.args = 0
	return stdcall(fn)
}

//go:nosplit
//go:cgo_unsafe_args
func stdcall1(fn stdFunction, a0 uintptr) uintptr {
	mp := getg().m
	mp.libcall.n = 1

//go:nosplit
//go:cgo_unsafe_args
func doMmap(addr, n, prot, flags, fd, off uintptr) (uintptr, uintptr) {
	var libcall libcall
	libcall.fn = uintptr(unsafe.Pointer(&libc_mmap))
	libcall.n = 6
	libcall.args = uintptr(noescape(unsafe.Pointer(&addr)))
	asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&libcall))
	return libcall.r1, libcall.err
}

//go:nosplit
func munmap(addr unsafe.Pointer, n uintptr) {

	freelink    *m // on sched.freem
	trace       mTraceState

	// these are here because they are too large to be on the stack
	// of low-level NOSPLIT functions.
	libcall    libcall
	libcallpc  uintptr // for cpu profiler
	libcallsp  uintptr
	libcallg   guintptr
	winsyscall winlibcall // stores syscall parameters on windows

	vdsoSP uintptr // SP for traceback while in VDSO call (0 if not in call)

	}
	if !isShrinkStackSafe(gp) {
		throw("shrinkstack at bad time")
	}
	// Check for self-shrinks while in a libcall. These may have
	// pointers into the stack disguised as uintptrs, but these
	// code paths should all be nosplit.
	if gp == getg().m.curg && gp.m.libcallsp != 0 {
		throw("shrinking stack in libcall")
	}

	if debug.gcshrinkstackoff > 0 {
		return
	}
	f := findfunc(gp.startpc)

		releasem(mp)
		return false
	}
	status := readgstatus(gp)
	if status&^_Gscan != _Grunning || gp.syscallsp != 0 {
		releasem(mp)
		return false
	}
	if GOOS == "windows" && mp.libcallsp != 0 {
		releasem(mp)
		return false
	}
	releasem(mp)
	return true
}

// shouldPushSigpanic reports whether pc should be used as sigpanic's