</contributor>
    <contributor>
      <name>Florencia Tarditti (PR 41)</name>
    </contributor>
    <contributor>
      <name>Anton Tanasenko</name>
    </contributor>
    <contributor>
      <name>Joseph Walton (MNG-5297)</name>
    </contributor>
    <contributor>
      <name>Fabiano Cipriano de Oliveira (MNG-6261)</name>
    </contributor>
    <contributor>

// stack gets modified.  We don't have a way to do that for gccgo
// without writing more assembly code, which we haven't bothered to
// do.  So this is not much of a test.

var Baton int32

func RewindAndSetgid() {
	atomic.StoreInt32(&Baton, 1)
	for atomic.LoadInt32(&Baton) != 0 {
		runtime.Gosched()
	}

	// will clobber the test pattern created by the caller
	ADD	$(1024*8), X2

	// Ask signaller to setgid
	MOV	$1, X5
	FENCE
	MOVW	X5, ·Baton(SB)
	FENCE

	// Wait for setgid completion
loop:
	FENCE
	MOVW	·Baton(SB), X5
	OR	X6, X6, X6	// hint that we're in a spin loop
	BNE	ZERO, X5, loop
	FENCE

	// Restore stack
	ADD	$(-1024*8), X2

	// Rewind stack pointer so anything that happens on the stack
	// will clobber the test pattern created by the caller
	ADDQ	$(1024 * 8), SP

	// Ask signaller to setgid
	MOVL	$1, ·Baton(SB)

	// Wait for setgid completion
loop:
	PAUSE
	MOVL	·Baton(SB), AX
	CMPL	AX, $0
	JNE	loop

	// Restore stack
	SUBQ	$(1024 * 8), SP

	// will clobber the test pattern created by the caller
	ADDU	$(1024*8), R29

	// Ask signaller to setgid
	MOVW	$1, R1
	SYNC
	MOVW	R1, ·Baton(SB)
	SYNC

	// Wait for setgid completion
loop:
	SYNC
	MOVW	·Baton(SB), R1
	OR	R2, R2, R2	// hint that we're in a spin loop
	BNE	R1, loop
	SYNC

	// Restore stack
	ADDU	$(-1024*8), R29

	// will clobber the test pattern created by the caller
	ADD	$(1024 * 8), R1

	// Ask signaller to setgid
	MOVW	$1, R3
	SYNC
	MOVW	R3, ·Baton(SB)

	// Wait for setgid completion
loop:
	SYNC
	MOVW	·Baton(SB), R3
	CMP	R3, $0
	// Hint that we're in a spin loop
	OR	R1, R1, R1
	BNE	loop
	ISYNC

	// Restore stack
	SUB	$(1024 * 8), R1

	// will clobber the test pattern created by the caller
	ADDV	$(1024*8), R29

	// Ask signaller to setgid
	MOVW	$1, R1
	SYNC
	MOVW	R1, ·Baton(SB)
	SYNC

	// Wait for setgid completion
loop:
	SYNC
	MOVW	·Baton(SB), R1
	OR	R2, R2, R2	// hint that we're in a spin loop
	BNE	R1, loop
	SYNC

	// Restore stack
	ADDV	$(-1024*8), R29

	// Start signaller
	atomic.StoreInt32(&issue9400.Baton, 0)
	go func() {
		// Wait for RewindAndSetgid
		for atomic.LoadInt32(&issue9400.Baton) == 0 {
			runtime.Gosched()
		}
		// Broadcast SIGSETXID
		runtime.LockOSThread()
		C.setgid(0)
		// Indicate that signalling is done
		atomic.StoreInt32(&issue9400.Baton, 0)
	}()

	// Grow the stack and put down a test pattern

	// will clobber the test pattern created by the caller
	ADD	$(1024 * 8), R15

	// Ask signaller to setgid
	MOVD	$·Baton(SB), R5
	MOVW	$1, 0(R5)

	// Wait for setgid completion
loop:
	SYNC
	MOVW	·Baton(SB), R3
	CMPBNE	R3, $0, loop

	// Restore stack
	SUB	$(1024 * 8), R15

	// will clobber the test pattern created by the caller
	ADDV	$(1024*8), R3

	// Ask signaller to setgid
	MOVW	$1, R12
	DBAR
	MOVW	R12, ·Baton(SB)
	DBAR

	// Wait for setgid completion
loop:
	DBAR
	MOVW	·Baton(SB), R12
	OR	R13, R13, R13	// hint that we're in a spin loop
	BNE	R12, loop
	DBAR

	// Restore stack
	ADDV	$(-1024*8), R3