1/* Copyright (C) 1997-2022 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/* clone() is even more special than fork() as it mucks with stacks
19   and invokes a function in the right context after its all over.  */
20
21#include <asm/errno.h>
22#include <tcb-offsets.h>
23#include <sysdep.h>
24
25/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
26	     pid_t *ptid, void *tls, pid_t *ctid); */
27
28	.register	%g2,#scratch
29	.register	%g3,#scratch
30
31	.text
32
33ENTRY (__clone)
34	save	%sp, -192, %sp
35	cfi_def_cfa_register(%fp)
36	cfi_window_save
37	cfi_register(%o7, %i7)
38
39	/* sanity check arguments */
40	brz,pn	%i0, 99f		/* fn non-NULL? */
41	 mov	%i0, %g2
42	brz,pn	%i1, 99f		/* child_stack non-NULL? */
43	 mov	%i2, %o0		/* clone flags */
44
45	/* The child_stack is the top of the stack, allocate one
46	   whole stack frame from that as this is what the kernel
47	   expects.  Also, subtract STACK_BIAS.  */
48	sub	%i1, 192 + 0x7ff, %o1
49	mov	%i3, %g3
50
51	mov	%i4,%o2			/* PTID */
52	mov	%i5,%o3			/* TLS */
53	ldx	[%fp+0x7ff+176],%o4	/* CTID */
54
55	/* Do the system call */
56	set	__NR_clone, %g1
57	ta	0x6d
58	bcs,pn	%xcc, 98f
59	 nop
60	brnz,pn	%o1, __thread_start
61	 nop
62	jmpl	%i7 + 8, %g0
63	 restore %o0, %g0, %o0
6499:	mov	EINVAL, %o0
6598:	call	HIDDEN_JUMPTARGET(__errno_location)
66	 mov	%o0, %i0
67	st	%i0, [%o0]
68	jmpl	%i7 + 8, %g0
69	 restore %g0,-1,%o0
70END(__clone)
71
72	.type __thread_start,@function
73__thread_start:
74	mov	%g0, %fp	/* terminate backtrace */
75	call	%g2
76	 mov	%g3,%o0
77	set	__NR_exit, %g1
78	ta	0x6d
79	 nop
80
81	.size	__thread_start, .-__thread_start
82
83libc_hidden_def (__clone)
84weak_alias (__clone, clone)
85