rt0_openbsd_arm64.s

     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  
    14  TEXT _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.
    21  TEXT _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  
    46  nocgo:
    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  
    54  restore:
    55  	// Restore callee-save registers.
    56  	RESTORE_R19_TO_R28(24)
    57  	RESTORE_F8_TO_F15(104)
    58  	RET
    59  
    60  TEXT _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  
    66  DATA _rt0_arm64_openbsd_lib_argc<>(SB)/8, $0
    67  GLOBL _rt0_arm64_openbsd_lib_argc<>(SB),NOPTR, $8
    68  DATA _rt0_arm64_openbsd_lib_argv<>(SB)/8, $0
    69  GLOBL _rt0_arm64_openbsd_lib_argv<>(SB),NOPTR, $8
    70  
    71  
    72  TEXT main(SB),NOSPLIT|NOFRAME,$0
    73  	MOVD	$runtime·rt0_go(SB), R2
    74  	BL	(R2)
    75  exit:
    76  	MOVD	$0, R0
    77  	MOVD	$1, R8		// sys_exit
    78  	INVOKE_SYSCALL
    79  	B	exit
    80
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