1 /* clone() implementation for Nios II.
2 Copyright (C) 2008-2015 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Andrew Jenner <andrew@codesourcery.com>, 2008.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
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 <tcb-offsets.h>
28 #define CLONE_VM 0x00000100
29 #define CLONE_THREAD 0x00010000
31 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
32 void *parent_tidptr, void *tls, void *child_tidptr) */
36 /* Sanity check arguments. */
38 /* No NULL function pointers. */
39 beq r4, zero, SYSCALL_ERROR_LABEL
40 /* No NULL stack pointers. */
41 beq r5, zero, SYSCALL_ERROR_LABEL
43 subi r5, r5, 8 /* Reserve argument save space. */
44 stw r4, 4(r5) /* Save function pointer. */
45 stw r7, 0(r5) /* Save argument pointer. */
53 /* Do the system call. */
54 movi r2, SYS_ify (clone)
56 /* End FDE now, because in the child the unwind info will be
61 /* Check for errors. */
62 bne r7, zero, SYSCALL_ERROR_LABEL
63 /* See if we're on the newly created thread. */
64 beq r2, zero, thread_start
65 /* Successful return from the parent */
72 /* We expect the argument registers to be preserved across system
73 calls and across task cloning, so flags should be in r4 here. */
74 andhi r2, r4, %hi(CLONE_THREAD)
81 stw r2, PID_OFFSET(r23)
82 stw r2, TID_OFFSET(r23)
84 ldw r5, 4(sp) /* Function pointer. */
85 ldw r4, 0(sp) /* Argument pointer. */
88 /* Call the user's function. */
91 /* _exit with the result. */
95 1: movhi r8, %hiadj(_gp_got - 1b)
96 addi r8, r8, %lo(_gp_got - 1b)
98 ldw r8, %call(HIDDEN_JUMPTARGET(_exit))(r22)
107 weak_alias (__clone, clone)