1/* Copyright (C) 1997-2017 Free Software Foundation, Inc.
2   Contributed by Richard Henderson (rth@tamu.edu).
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   <http://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 <asm/unistd.h>
23#include <sysdep.h>
24
25#define CLONE_VM	0x00000100
26
27/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
28	     pid_t *ptid, void *tls, pid_t *ctid); */
29
30	.register	%g2,#scratch
31	.register	%g3,#scratch
32
33	.text
34
35ENTRY (__clone)
36	save	%sp, -192, %sp
37	cfi_def_cfa_register(%fp)
38	cfi_window_save
39	cfi_register(%o7, %i7)
40
41	/* sanity check arguments */
42	brz,pn	%i0, 99f		/* fn non-NULL? */
43	 mov	%i0, %g2
44	brz,pn	%i1, 99f		/* child_stack non-NULL? */
45	 mov	%i2, %o0		/* clone flags */
46
47	/* The child_stack is the top of the stack, allocate one
48	   whole stack frame from that as this is what the kernel
49	   expects.  Also, subtract STACK_BIAS.  */
50	sub	%i1, 192 + 0x7ff, %o1
51	mov	%i3, %g3
52
53	mov	%i4,%o2			/* PTID */
54	mov	%i5,%o3			/* TLS */
55	ldx	[%fp+0x7ff+176],%o4	/* CTID */
56
57	/* Do the system call */
58	set	__NR_clone, %g1
59	ta	0x6d
60	bcs,pn	%xcc, 98f
61	 nop
62	brnz,pn	%o1, __thread_start
63	 nop
64	jmpl	%i7 + 8, %g0
65	 restore %o0, %g0, %o0
6699:	mov	EINVAL, %o0
6798:	call	__errno_location
68	 mov	%o0, %i0
69	st	%i0, [%o0]
70	jmpl	%i7 + 8, %g0
71	 restore %g0,-1,%o0
72END(__clone)
73
74	.type __thread_start,@function
75__thread_start:
76	mov	%g0, %fp	/* terminate backtrace */
77	call	%g2
78	 mov	%g3,%o0
79	call	HIDDEN_JUMPTARGET(_exit),0
80	 nop
81
82	.size	__thread_start, .-__thread_start
83
84libc_hidden_def(__clone)
85weak_alias(__clone, clone)
86