MOVL	ureg+0(FP), CX
	MOVL	note+4(FP), DX

	// change stack
	MOVL	g_m(BX), BX
	MOVL	m_gsignal(BX), BP
	MOVL	(g_stack+stack_hi)(BP), BP
	MOVL	BP, SP

	// make room for args and g
	SUBL	$24, SP

	// save g
	MOVL	g(AX), BP
	MOVL	BP, 20(SP)

	// g = m->gsignal
	MOVL	m_gsignal(BX), DI
	MOVL	DI, g(AX)

	// load args and call sighandler
	MOVL	CX, 0(SP)
	MOVL	DX, 4(SP)

	// save args
	MOVW	ureg+0(FP), R1
	MOVW	note+4(FP), R2

	// change stack
	MOVW	m_gsignal(R0), R3
	MOVW	(g_stack+stack_hi)(R3), R13

	// make room for args, retval and g
	SUB	$24, R13

	// save g
	MOVW	g, R3
	MOVW	R3, 20(R13)

	// g = m->gsignal
	MOVW	m_gsignal(R0), g

	// load args and call sighandler
	ADD	$4,R13,R5
	MOVM.IA	[R1-R3], (R5)

	// save args
	MOVQ	ureg+0(FP), CX
	MOVQ	note+8(FP), DX

	// change stack
	MOVQ	g_m(BX), BX
	MOVQ	m_gsignal(BX), R10
	MOVQ	(g_stack+stack_hi)(R10), BP
	MOVQ	BP, SP

	// make room for args and g
	SUBQ	$128, SP

	// save g
	MOVQ	g(AX), BP
	MOVQ	BP, 32(SP)

	// g = m->gsignal
	MOVQ	R10, g(AX)

	// load args and call sighandler
	MOVQ	CX, 0(SP)
	MOVQ	DX, 8(SP)
	MOVQ	BP, 16(SP)

	MOVD	R15, R3			// R15 needs to be in R3 as expected by kernel_clock_gettime

	MOVB	runtime·iscgo(SB),R12
	CMPBNE	R12, $0, nosaveg

	MOVD	m_gsignal(R6), R12	// g.m.gsignal
	CMPBEQ	R12, $0, nosaveg

	CMPBEQ	g, R12, nosaveg
	MOVD	(g_stack+stack_lo)(R12), R12 // g.m.gsignal.stack.lo
	MOVD	g, (R12)

	BL	R9 // to vdso lookup

	MOVD	$0, (R12)

	JMP	finish

nosaveg:
	BL	R9					// to vdso lookup

	MOV	$8(X2), A1

	// Store g on gsignal's stack, see sys_linux_arm64.s for detail
	MOVBU	runtime·iscgo(SB), S4
	BNEZ	S4, nosaveg
	MOV	m_gsignal(S3), S4 // g.m.gsignal
	BEQZ	S4, nosaveg
	BEQ	g, S4, nosaveg
	MOV	(g_stack+stack_lo)(S4), S4 // g.m.gsignal.stack.lo
	MOV	g, (S4)

	JALR	RA, A7

	MOV	ZERO, (S4)
	JMP	finish

nosaveg:
	JALR	RA, A7

finish:
	MOV	8(X2), T0	// sec

	MOVV	fn+0(FP), R1	// R1 = fn
	MOVV	R1, REGCTXT		// context
	MOVV	g_m(g), R2	// R2 = m

	MOVV	m_gsignal(R2), R3	// R3 = gsignal
	BEQ	g, R3, noswitch

	MOVV	m_g0(R2), R3	// R3 = g0
	BEQ	g, R3, noswitch

	MOVV	m_curg(R2), R4
	BEQ	g, R4, switch

	// Bad: g is not gsignal, not g0, not curg. What is it?
	// Hide call from linker nosplit analysis.
	MOVV	$runtime·badsystemstack(SB), R4
	JAL	(R4)

	BEQ	R20, fallback

	// Store g on gsignal's stack, see sys_linux_arm64.s for detail
	MOVBU	runtime·iscgo(SB), R25
	BNE	R25, nosaveg

	MOVV	m_gsignal(R24), R25	// g.m.gsignal
	BEQ	R25, nosaveg
	BEQ	g, R25, nosaveg

	MOVV	(g_stack+stack_lo)(R25), R25	// g.m.gsignal.stack.lo
	MOVV	g, (R25)

	JAL	(R20)

	MOVV	R0, (R25)
	JMP	finish

nosaveg:
	JAL	(R20)

finish:

TEXT runtime·systemstack(SB), NOSPLIT, $0-8
	MOV	fn+0(FP), CTXT	// CTXT = fn
	MOV	g_m(g), T0	// T0 = m

	MOV	m_gsignal(T0), T1	// T1 = gsignal
	BEQ	g, T1, noswitch

	MOV	m_g0(T0), T1	// T1 = g0
	BEQ	g, T1, noswitch

	MOV	m_curg(T0), T2
	BEQ	g, T2, switch

	// Bad: g is not gsignal, not g0, not curg. What is it?
	// Hide call from linker nosplit analysis.
	MOV	$runtime·badsystemstack(SB), T1
	JALR	RA, T1

	MOVD	fn+0(FP), R3	// R3 = fn
	MOVD	R3, R12		// context
	MOVD	g_m(g), R4	// R4 = m

	MOVD	m_gsignal(R4), R5	// R5 = gsignal
	CMPBEQ	g, R5, noswitch

	MOVD	m_g0(R4), R5	// R5 = g0
	CMPBEQ	g, R5, noswitch

	MOVD	m_curg(R4), R6
	CMPBEQ	g, R6, switch

	// Bad: g is not gsignal, not g0, not curg. What is it?
	// Hide call from linker nosplit analysis.
	MOVD	$runtime·badsystemstack(SB), R3

	MOVW	fn+0(FP), R1	// R1 = fn
	MOVW	R1, REGCTXT	// context
	MOVW	g_m(g), R2	// R2 = m

	MOVW	m_gsignal(R2), R3	// R3 = gsignal
	BEQ	g, R3, noswitch

	MOVW	m_g0(R2), R3	// R3 = g0
	BEQ	g, R3, noswitch

	MOVW	m_curg(R2), R4
	BEQ	g, R4, switch

	// Bad: g is not gsignal, not g0, not curg. What is it?
	// Hide call from linker nosplit analysis.
	MOVW	$runtime·badsystemstack(SB), R4
	JAL	(R4)