1 /* Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Richard Henderson (rth@tamu.edu)
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 /* clone() is even more special than fork() as it mucks with stacks
21 and invokes a function in the right context after its all over. */
25 #include <bits/errno.h>
26 #include <asm-syntax.h>
30 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
32 #define PARMS LINKAGE /* no space for saved regs */
35 #define FLAGS STACK+PTR_SIZE
39 ENTRY (BP_SYM (__clone))
40 /* Sanity check arguments. */
42 movl FUNC(%esp),%ecx /* no NULL function pointers */
44 jecxz SYSCALL_ERROR_LABEL
47 jz SYSCALL_ERROR_LABEL
49 movl STACK(%esp),%ecx /* no NULL stack pointers */
51 jecxz SYSCALL_ERROR_LABEL
54 jz SYSCALL_ERROR_LABEL
57 /* Insert the argument onto the new stack. */
59 movl ARG(%esp),%eax /* no negative argument counts */
62 /* Save the function pointer as the zeroth argument.
63 It will be popped off in the child in the ebx frobbing below. */
67 /* Do the system call */
69 movl FLAGS+4(%esp),%ebx
70 movl $SYS_ify(clone),%eax
75 jl SYSCALL_ERROR_LABEL
82 subl %ebp,%ebp /* terminate the stack frame */
88 addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx
91 call JUMPTARGET (_exit)
93 PSEUDO_END (BP_SYM (__clone))
95 weak_alias (BP_SYM (__clone), BP_SYM (clone))