1/* Copyright (C) 2005-2018 Free Software Foundation, Inc.
2
3   The GNU C Library is free software; you can redistribute it and/or
4   modify it under the terms of the GNU Lesser General Public
5   License as published by the Free Software Foundation; either
6   version 2.1 of the License, or (at your option) any later version.
7
8   The GNU C Library is distributed in the hope that it will be useful,
9   but WITHOUT ANY WARRANTY; without even the implied warranty of
10   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
11   Lesser General Public License for more details.
12
13   You should have received a copy of the GNU Lesser General Public
14   License along with the GNU C Library.  If not, see
15   <http://www.gnu.org/licenses/>.  */
16
17#include <sysdep.h>
18#define _ERRNO_H        1
19#include <bits/errno.h>
20
21/* Clone the calling process, but without copying the whole address space.
22   The calling process is suspended until the new process exits or is
23   replaced by a call to `execve'.  Return -1 for errors, 0 to the new process,
24   and the process ID of the new process to the old process.  */
25
26.Lthread_start:						ASM_LINE_SEP
27
28	/* r26, r25, r24, r23 are free since vfork has no arguments */
29ENTRY(__vfork)
30	/* We must not create a frame. When the child unwinds to call
31	   exec it will clobber the same frame that the parent
32	   needs to unwind.  */
33
34	/* Save the PIC register. */
35#ifdef __PIC__
36	copy	%r19, %r25	/* parent */
37#endif
38
39	/* Syscall saves and restores all register states */
40	ble	0x100(%sr2,%r0)
41	ldi	__NR_vfork,%r20
42
43	/* Check for error */
44	ldi	-4096,%r1
45	comclr,>>= %r1,%ret0,%r0        /* Note: unsigned compare. */
46	b,n	.Lerror
47
48	/* Return, and DO NOT restore rp. The child may have called
49	   functions that updated the frame's rp. This works because
50	   the kernel ensures rp is preserved across the vfork
51	   syscall.  */
52	bv,n	%r0(%rp)
53
54.Lerror:
55	/* Now we need a stack to call a function. We are assured
56	   that there is no child now, so it's safe to create
57	   a frame.  */
58	stw	%rp, -20(%sp)
59	.cfi_offset 2, -20
60	stwm	%r3, 64(%sp)
61	.cfi_def_cfa_offset -64
62	.cfi_offset 3, 0
63	stw	%sp, -4(%sp)
64
65	sub	%r0,%ret0,%r3
66	SYSCALL_ERROR_HANDLER
67	/* Restore the PIC register (in delay slot) on error */
68#ifdef __PIC__
69	copy	%r25, %r19    /* parent */
70#else
71	nop
72#endif
73	/* Write syscall return into errno location */
74	stw	%r3, 0(%ret0)
75	ldw	-84(%sp), %rp
76	bv	%r0(%rp)
77	ldwm	-64(%sp), %r3
78
79PSEUDO_END (__vfork)
80libc_hidden_def(vfork)
81
82weak_alias (__vfork, vfork)
83