/* Copyright (C) 2000-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

#include <asm/errno.h>

/* int  __clone2(int (*fn) (void *arg), void *child_stack_base, 	*/

/* 	         size_t child_stack_size, int flags, void *arg,		*/

/*	         pid_t *parent_tid, void *tls, pid_t *child_tid)	*/

#define CHILD	p8

#define PARENT	p9

ENTRY(__clone2)

	.prologue

	alloc r2=ar.pfs,8,1,6,0

	cmp.eq p6,p0=0,in0

	cmp.eq p7,p0=0,in1

	mov r8=EINVAL

	mov out0=in3		/* Flags are first syscall argument.	*/

	mov out1=in1		/* Stack address.			*/

(p6)	br.cond.spnt.many __syscall_error	/* no NULL function pointers */

(p7)	br.cond.spnt.many __syscall_error	/* no NULL stack pointers */

	;;

	mov out2=in2		/* Stack size.				*/

	mov out3=in5		/* Parent TID Pointer			*/

	mov out4=in7		/* Child TID Pointer			*/

	mov out5=in6		/* TLS pointer				*/

	/*

	 * clone2() is special: the child cannot execute br.ret right

	 * after the system call returns, because it starts out

	 * executing on an empty stack.  Because of this, we can't use

	 * the new (lightweight) syscall convention here.  Instead, we

	 * just fall back on always using "break".

	 *

	 * Furthermore, since the child starts with an empty stack, we

	 * need to avoid unwinding past invalid memory.  To that end,

	 * we'll pretend now that __clone2() is the end of the

	 * call-chain.  This is wrong for the parent, but only until

	 * it returns from clone2() but it's better than the

	 * alternative.

	 */

	mov r15=SYS_ify (clone2)

	.save rp, r0

	break __BREAK_SYSCALL

	.body

	cmp.eq p6,p0=-1,r10

	cmp.eq CHILD,PARENT=0,r8 /* Are we the child?   */

(p6)	br.cond.spnt.many __syscall_error

	;;

(CHILD)	mov loc0=gp

(PARENT) ret

	;;

	ld8 out1=[in0],8	/* Retrieve code pointer.	*/

	mov out0=in4		/* Pass proper argument	to fn */

	;;

	ld8 gp=[in0]		/* Load function gp.		*/

	mov b6=out1

	br.call.dptk.many rp=b6	/* Call fn(arg) in the child 	*/

	;;

	mov out0=r8		/* Argument to exit		*/

	mov gp=loc0

	mov r15=SYS_ify (exit)

	.save rp, r0

	break __BREAK_SYSCALL

	ret			/* Not reached.		*/

PSEUDO_END(__clone2)

libc_hidden_def (__clone2)

/* For now we leave __clone undefined.  This is unlikely to be a	*/

/* problem, since at least the i386 __clone in glibc always failed	*/

/* with a 0 sp (eventhough the kernel explicitly handled it).		*/

/* Thus all such calls needed to pass an explicit sp, and as a result,	*/

/* would be unlikely to work on ia64.					*/