1/* Copyright (C) 2000-2022 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Lesser General Public
6   License as published by the Free Software Foundation; either
7   version 2.1 of the License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with the GNU C Library; if not, see
16   <https://www.gnu.org/licenses/>.  */
17
18
19#include <sysdep.h>
20#include <asm/errno.h>
21
22
23/* int  __clone2(int (*fn) (void *arg), void *child_stack_base, 	*/
24/* 	         size_t child_stack_size, int flags, void *arg,		*/
25/*	         pid_t *parent_tid, void *tls, pid_t *child_tid)	*/
26
27#define CHILD	p8
28#define PARENT	p9
29
30ENTRY(__clone2)
31	.prologue
32	alloc r2=ar.pfs,8,1,6,0
33	cmp.eq p6,p0=0,in0
34	cmp.eq p7,p0=0,in1
35	mov r8=EINVAL
36	mov out0=in3		/* Flags are first syscall argument.	*/
37	mov out1=in1		/* Stack address.			*/
38(p6)	br.cond.spnt.many __syscall_error	/* no NULL function pointers */
39(p7)	br.cond.spnt.many __syscall_error	/* no NULL stack pointers */
40	;;
41	mov out2=in2		/* Stack size.				*/
42	mov out3=in5		/* Parent TID Pointer			*/
43	mov out4=in7		/* Child TID Pointer			*/
44	mov out5=in6		/* TLS pointer				*/
45	/*
46	 * clone2() is special: the child cannot execute br.ret right
47	 * after the system call returns, because it starts out
48	 * executing on an empty stack.  Because of this, we can't use
49	 * the new (lightweight) syscall convention here.  Instead, we
50	 * just fall back on always using "break".
51	 *
52	 * Furthermore, since the child starts with an empty stack, we
53	 * need to avoid unwinding past invalid memory.  To that end,
54	 * we'll pretend now that __clone2() is the end of the
55	 * call-chain.  This is wrong for the parent, but only until
56	 * it returns from clone2() but it's better than the
57	 * alternative.
58	 */
59	mov r15=SYS_ify (clone2)
60	.save rp, r0
61	break __IA64_BREAK_SYSCALL
62	.body
63	cmp.eq p6,p0=-1,r10
64	cmp.eq CHILD,PARENT=0,r8 /* Are we the child?   */
65(p6)	br.cond.spnt.many __syscall_error
66	;;
67(CHILD)	mov loc0=gp
68(PARENT) ret
69	;;
70	ld8 out1=[in0],8	/* Retrieve code pointer.	*/
71	mov out0=in4		/* Pass proper argument	to fn */
72	;;
73	ld8 gp=[in0]		/* Load function gp.		*/
74	mov b6=out1
75	br.call.dptk.many rp=b6	/* Call fn(arg) in the child 	*/
76	;;
77	mov out0=r8		/* Argument to exit		*/
78	mov gp=loc0
79	mov r15=SYS_ify (exit)
80	.save rp, r0
81	break __IA64_BREAK_SYSCALL
82	ret			/* Not reached.		*/
83PSEUDO_END(__clone2)
84
85libc_hidden_def (__clone2)
86
87/* For now we leave __clone undefined.  This is unlikely to be a	*/
88/* problem, since at least the i386 __clone in glibc always failed	*/
89/* with a 0 sp (eventhough the kernel explicitly handled it).		*/
90/* Thus all such calls needed to pass an explicit sp, and as a result,	*/
91/* would be unlikely to work on ia64.					*/
92