/* Copyright (C) 1996-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Richard Henderson <rth@tamu.edu>, 1996.

   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/>.  */

/* clone() is even more special than fork() as it mucks with stacks

   and invokes a function in the right context after its all over.  */

#include <sysdep.h>

#define _ERRNO_H	1

#include <bits/errno.h>

/* int clone(int (*fn)(void *arg), void *child_stack, int flags,

	     void *arg, pid_t *ptid, void *tls, pid_t *ctid);

   Note that everything past ARG is technically optional, based

   on FLAGS, and that CTID is arg 7, and thus is on the stack.

   However, since a load from top-of-stack better be legal always,

   we don't bother checking FLAGS.  */

        .text

	.align	4

	.globl	__clone

	.ent	__clone

	.usepv	__clone, USEPV_PROF

	cfi_startproc

__clone:

#ifdef PROF

	.set noat

	ldgp	gp,0(pv)

	lda	AT, _mcount

	jsr	AT, (AT), _mcount

	.set at

#endif

	/* Sanity check arguments.  */

	ldiq	v0, EINVAL

	beq	a0, SYSCALL_ERROR_LABEL	/* no NULL function pointers */

	beq	a1, SYSCALL_ERROR_LABEL	/* no NULL stack pointers */

	/* Save the fn ptr and arg on the new stack.  */

	subq	a1, 32, a1

	stq	a0, 0(a1)

	stq	a3, 8(a1)

	stq	a2, 16(a1)

	/* The syscall is of the form clone(flags, usp, ptid, ctid, tls).

	   Shift the flags, ptid, ctid, tls arguments into place; the

	   child_stack argument is already correct.  */

	mov	a2, a0

	mov	a4, a2

	ldq	a3, 0(sp)

	mov	a5, a4

	/* Do the system call.  */

	ldiq	v0, __NR_clone

	call_pal PAL_callsys

	bne	a3, SYSCALL_ERROR_LABEL

	beq	v0, thread_start

	/* Successful return from the parent.  */

	ret

PSEUDO_END(__clone)

	cfi_endproc

/* Load up the arguments to the function.  Put this block of code in

   its own function so that we can terminate the stack trace with our

   debug info.  */

	.align	4

	.ent thread_start

	cfi_startproc

thread_start:

	mov	0, fp

	cfi_def_cfa_register(fp)

	cfi_undefined(ra)

	/* Load up the arguments.  */

	ldq	pv, 0(sp)

	ldq	a0, 8(sp)

	addq	sp, 32, sp

	/* Call the user's function.  */

	jsr	ra, (pv)

	ldgp	gp, 0(ra)

	mov     v0, a0

	ldiq	v0, __NR_exit

	call_pal PAL_callsys

	/* Die horribly.  */

	.align	4

	halt

	.align	4

	cfi_endproc

	.end thread_start

libc_hidden_def (__clone)

weak_alias (__clone, clone)