1 /* Copyright (C) 2000, 2001, 2003, 2004, 2006 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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/>. */
19 #include <asm/errno.h>
21 /* int __clone2(int (*fn) (void *arg), void *child_stack_base, */
22 /* size_t child_stack_size, int flags, void *arg, */
23 /* pid_t *parent_tid, void *tls, pid_t *child_tid) */
30 alloc r2=ar.pfs,8,1,6,0
34 mov out0=in3 /* Flags are first syscall argument. */
35 mov out1=in1 /* Stack address. */
36 (p6) br.cond.spnt.many __syscall_error /* no NULL function pointers */
37 (p7) br.cond.spnt.many __syscall_error /* no NULL stack pointers */
39 mov out2=in2 /* Stack size. */
40 mov out3=in5 /* Parent TID Pointer */
41 mov out4=in7 /* Child TID Pointer */
42 mov out5=in6 /* TLS pointer */
44 * clone2() is special: the child cannot execute br.ret right
45 * after the system call returns, because it starts out
46 * executing on an empty stack. Because of this, we can't use
47 * the new (lightweight) syscall convention here. Instead, we
48 * just fall back on always using "break".
50 * Furthermore, since the child starts with an empty stack, we
51 * need to avoid unwinding past invalid memory. To that end,
52 * we'll pretend now that __clone2() is the end of the
53 * call-chain. This is wrong for the parent, but only until
54 * it returns from clone2() but it's better than the
57 mov r15=SYS_ify (clone2)
62 cmp.eq CHILD,PARENT=0,r8 /* Are we the child? */
63 (p6) br.cond.spnt.many __syscall_error
68 1: ld8 out1=[in0],8 /* Retrieve code pointer. */
69 mov out0=in4 /* Pass proper argument to fn */
71 ld8 gp=[in0] /* Load function gp. */
73 br.call.dptk.many rp=b6 /* Call fn(arg) in the child */
75 mov out0=r8 /* Argument to _exit */
77 .globl HIDDEN_JUMPTARGET(_exit)
78 br.call.dpnt.many rp=HIDDEN_JUMPTARGET(_exit)
79 /* call _exit with result from fn. */
80 ret /* Not reached. */
83 /* For now we leave __clone undefined. This is unlikely to be a */
84 /* problem, since at least the i386 __clone in glibc always failed */
85 /* with a 0 sp (eventhough the kernel explicitly handled it). */
86 /* Thus all such calls needed to pass an explicit sp, and as a result, */
87 /* would be unlikely to work on ia64. */