// PC on the stack, then put it in the LR before calling sigpanic.

	// Build a 32-byte stack frame for us for this call.
	// Saved LR (none available) is at the bottom,
	// then the PC argument for setsigsegv,
	// then a copy of the LR for us to restore.
	MOVD.W $0, -32(RSP)
	MOVD R1, 8(RSP)
	MOVD R2, 16(RSP)
	BL runtime·setsigsegv(SB)
	MOVD 8(RSP), R1
	MOVD 16(RSP), R2

	st := stackt{ss_size: s.hi - s.lo}
	setSignalstackSP(&st, s.lo)
	sigaltstack(&st, nil)
}

// setsigsegv is used on darwin/arm64 to fake a segmentation fault.
//
// This is exported via linkname to assembly in runtime/cgo.
//
//go:nosplit
//go:linkname setsigsegv
func setsigsegv(pc uintptr) {
	gp := getg()
	gp.sig = _SIGSEGV
	gp.sigpc = pc
	gp.sigcode0 = _SEGV_MAPERR