1// Copyright 2019 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "textflag.h"
6#include "cgo/abi_arm64.h"
7
8// See comment in runtime/sys_openbsd_arm64.s re this construction.
9#define	INVOKE_SYSCALL	\
10	SVC;		\
11	NOOP;		\
12	NOOP
13
14TEXT _rt0_arm64_openbsd(SB),NOSPLIT|NOFRAME,$0
15	MOVD	0(RSP), R0	// argc
16	ADD	$8, RSP, R1	// argv
17	BL	main(SB)
18
19// When building with -buildmode=c-shared, this symbol is called when the shared
20// library is loaded.
21TEXT _rt0_arm64_openbsd_lib(SB),NOSPLIT,$184
22	// Preserve callee-save registers.
23	SAVE_R19_TO_R28(24)
24	SAVE_F8_TO_F15(104)
25
26	// Initialize g as null in case of using g later e.g. sigaction in cgo_sigaction.go
27	MOVD	ZR, g
28
29	MOVD	R0, _rt0_arm64_openbsd_lib_argc<>(SB)
30	MOVD	R1, _rt0_arm64_openbsd_lib_argv<>(SB)
31
32	// Synchronous initialization.
33	MOVD	$runtime·libpreinit(SB), R4
34	BL	(R4)
35
36	// Create a new thread to do the runtime initialization and return.
37	MOVD	_cgo_sys_thread_create(SB), R4
38	CBZ	R4, nocgo
39	MOVD	$_rt0_arm64_openbsd_lib_go(SB), R0
40	MOVD	$0, R1
41	SUB	$16, RSP		// reserve 16 bytes for sp-8 where fp may be saved.
42	BL	(R4)
43	ADD	$16, RSP
44	B	restore
45
46nocgo:
47	MOVD	$0x800000, R0                     // stacksize = 8192KB
48	MOVD	$_rt0_arm64_openbsd_lib_go(SB), R1
49	MOVD	R0, 8(RSP)
50	MOVD	R1, 16(RSP)
51	MOVD	$runtime·newosproc0(SB),R4
52	BL	(R4)
53
54restore:
55	// Restore callee-save registers.
56	RESTORE_R19_TO_R28(24)
57	RESTORE_F8_TO_F15(104)
58	RET
59
60TEXT _rt0_arm64_openbsd_lib_go(SB),NOSPLIT,$0
61	MOVD	_rt0_arm64_openbsd_lib_argc<>(SB), R0
62	MOVD	_rt0_arm64_openbsd_lib_argv<>(SB), R1
63	MOVD	$runtime·rt0_go(SB),R4
64	B       (R4)
65
66DATA _rt0_arm64_openbsd_lib_argc<>(SB)/8, $0
67GLOBL _rt0_arm64_openbsd_lib_argc<>(SB),NOPTR, $8
68DATA _rt0_arm64_openbsd_lib_argv<>(SB)/8, $0
69GLOBL _rt0_arm64_openbsd_lib_argv<>(SB),NOPTR, $8
70
71
72TEXT main(SB),NOSPLIT|NOFRAME,$0
73	MOVD	$runtime·rt0_go(SB), R2
74	BL	(R2)
75exit:
76	MOVD	$0, R0
77	MOVD	$1, R8		// sys_exit
78	INVOKE_SYSCALL
79	B	exit
80