// we cannot receive another signal.
	MOVV	16(R29), R1
	MOVV	R1, m_vdsoSP(R17)
	MOVV	8(R29), R1
	MOVV	R1, m_vdsoPC(R17)

	// sec is in R3, nsec in R5
	// return nsec in R3
	MOVV	$1000000000, R4
	MULVU	R4, R3
	MOVV	LO, R3
	ADDVU	R5, R3
	MOVV	R3, ret+0(FP)
	RET

fallback:
	MOVV	$SYS_clock_gettime, R2
	SYSCALL
	JMP	finish

	// we cannot receive another signal.

	MOVD	24(R15), R12
	MOVD	R12, m_vdsoSP(R6)
	MOVD	16(R15), R12
	MOVD	R12, m_vdsoPC(R6)

return:
	// sec is in R3, nsec in R5
	// return nsec in R3
	MULLD	$1000000000, R3
	ADD		R5, R3
	MOVD	R3, ret+0(FP)
	RET

	// Syscall fallback
fallback:
	MOVD	$tp-16(SP), R3
	MOVD	$SYS_clock_gettime, R1
	SYSCALL
	LMG		tp-16(SP), R2, R3
	MOVD	R3, R5
	MOVD	R2, R3

	MOVL	$SYS_clock_gettime, AX
	MOVQ	$CLOCK_MONOTONIC, DI
	LEAQ	8(SP), SI
	SYSCALL
	MOVQ	8(SP), AX	// sec
	MOVQ	16(SP), DX	// nsec

	// sec is in AX, nsec in DX
	// return nsec in AX
	IMULQ	$1000000000, AX
	ADDQ	DX, AX
	MOVQ	AX, ret+0(FP)
	RET

TEXT runtime·asmSigaction(SB),NOSPLIT,$0
	MOVQ	sig+0(FP), DI		// arg 1 sig
	MOVQ	new+8(FP), SI		// arg 2 act
	MOVQ	old+16(FP), DX		// arg 3 oact

	BL	runtime·vdsoCall(SB)

	JMP	finish

fallback:
	MOVW	$SYS_clock_gettime, R7
	SWI	$0

finish:
	MOVW	sec-12(SP), R0  // sec
	MOVW	nsec-8(SP), R2  // nsec

	MOVW	$1000000000, R3
	MULLU	R0, R3, (R1, R0)
	ADD.S	R2, R0
	ADC	$0, R1	// Add carry bit to upper half.

	MOVW	R0, ret_lo+0(FP)
	MOVW	R1, ret_hi+4(FP)

	RET

// int32 futex(int32 *uaddr, int32 op, int32 val,

	// we cannot receive another signal.
	MOVD	40(R1), R6
	MOVD	R6, m_vdsoSP(R21)
	MOVD	32(R1), R6
	MOVD	R6, m_vdsoPC(R21)

return:
	// sec is in R3, nsec in R5
	// return nsec in R3
	MOVD	$1000000000, R4
	MULLD	R4, R3
	ADD	R5, R3
	MOVD	R3, ret+0(FP)
	RET

	// Syscall fallback
fallback:
	ADD	$32, R1, R4
	SYSCALL $SYS_clock_gettime
	MOVD	32(R1), R3
	MOVD	40(R1), R5
	JMP	return

	// we cannot receive another signal.
	MOVQ	8(SP), CX
	MOVQ	CX, m_vdsoSP(BX)
	MOVQ	0(SP), CX
	MOVQ	CX, m_vdsoPC(BX)
	// sec is in AX, nsec in DX
	// return nsec in AX
	IMULQ	$1000000000, AX
	ADDQ	DX, AX
	MOVQ	AX, ret+0(FP)
	RET
fallback:
	MOVQ	$SYS_clock_gettime, AX
	SYSCALL
	JMP	ret

TEXT runtime·rtsigprocmask(SB),NOSPLIT,$0-28
	MOVL	how+0(FP), DI
	MOVQ	new+8(FP), SI

	// we cannot receive another signal.
	MOVL	4(SP), CX
	MOVL	CX, m_vdsoSP(SI)
	MOVL	0(SP), CX
	MOVL	CX, m_vdsoPC(SI)

	// sec is in AX, nsec in BX
	// convert to DX:AX nsec
	MOVL	$1000000000, CX
	MULL	CX
	ADDL	BX, AX
	ADCL	$0, DX

	MOVL	AX, ret_lo+0(FP)
	MOVL	DX, ret_hi+4(FP)
	RET

TEXT runtime·rtsigprocmask(SB),NOSPLIT,$0
	MOVL	$SYS_rt_sigprocmask, AX
	MOVL	how+0(FP), BX

	// we cannot receive another signal.
	MOVD	16(RSP), R1
	MOVD	R1, m_vdsoSP(R21)
	MOVD	8(RSP), R1
	MOVD	R1, m_vdsoPC(R21)

	// sec is in R3, nsec in R5
	// return nsec in R3
	MOVD	$1000000000, R4
	MUL	R4, R3
	ADD	R5, R3
	MOVD	R3, ret+0(FP)
	RET

TEXT runtime·rtsigprocmask(SB),NOSPLIT|NOFRAME,$0-28
	MOVW	how+0(FP), R0
	MOVD	new+8(FP), R1
	MOVD	old+16(FP), R2
	MOVW	size+24(FP), R3

	t0 := runtime.Nanotime1()
	var secrem uint32
	var nsecrem uint32
	total := time.Sec*1000000000 + time.Nsec
	elapsed := runtime.Nanotime1() - t0
	var rv int32
	var rc int32
	var err error
	// repeatedly sleep for 1 second until less than 1 second left
	for total-elapsed > 1000000000 {
		rv, rc, _ = BpxCondTimedWait(uint32(1), uint32(0), uint32(CW_CONDVAR), &secrem, &nsecrem)

func tempFile(ctx context.Context, dir, prefix string, perm fs.FileMode) (f *os.File, err error) {
	for i := 0; i < 10000; i++ {
		name := filepath.Join(dir, prefix+strconv.Itoa(rand.Intn(1000000000))+".tmp")
		f, err = os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)
		if os.IsExist(err) {
			if ctx.Err() != nil {
				return nil, ctx.Err()
			}
			continue
		}
		break
	}
	return