1 /* Copyright (C) 1996-2024 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 <https://www.gnu.org/licenses/>. */
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. */
23 #include <bits/errno.h>
25 /* int clone(int (*fn)(void *arg), void *child_stack, int flags,
26 void *arg, pid_t *ptid, void *tls, pid_t *ctid);
28 Note that everything past ARG is technically optional, based
29 on FLAGS, and that CTID is arg 7, and thus is on the stack.
30 However, since a load from top-of-stack better be legal always,
31 we don't bother checking FLAGS. */
37 .usepv __clone, USEPV_PROF
49 /* Sanity check arguments. */
51 beq a0, SYSCALL_ERROR_LABEL /* no NULL function pointers */
52 beq a1, SYSCALL_ERROR_LABEL /* no NULL stack pointers */
54 /* Save the fn ptr and arg on the new stack. */
60 /* The syscall is of the form clone(flags, usp, ptid, ctid, tls).
61 Shift the flags, ptid, ctid, tls arguments into place; the
62 child_stack argument is already correct. */
68 /* Do the system call. */
72 bne a3, SYSCALL_ERROR_LABEL
75 /* Successful return from the parent. */
81 /* Load up the arguments to the function. Put this block of code in
82 its own function so that we can terminate the stack trace with our
90 cfi_def_cfa_register(fp)
93 /* Load up the arguments. */
98 /* Call the user's function. */
114 libc_hidden_def (__clone)
115 weak_alias (__clone, clone)