/* Copyright (C) 2001, 2005, 2007 Free Software Foundation, Inc. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ /* clone is even more special than fork as it mucks with stacks and invokes a function in the right context after it's all over. */ #include "sysdep.h" #include <sys/syscall.h> #define _ERRNO_H 1 #include <bits/errno.h> /* int clone (a2 = int (*fn)(void *arg), a3 = void *child_stack, a4 = int flags, a5 = void *arg, a6 = pid_t *ptid, a7 = struct user_desc *tls, 16(sp) = pid_t *ctid) */ .text ENTRY (__clone) /* Sanity check arguments. */ beqz a2, .Leinval /* no NULL function pointers */ beqz a3, .Leinval /* no NULL stack pointers */ /* a2 and a3 are candidates for destruction by system-call return parameters. We don't need the stack pointer after the system call. We trust that the kernel will preserve a7, a9, and a6. */ mov a9, a5 /* save function argument */ mov a5, a7 mov a7, a2 /* save function pointer */ mov a8, a6 /* use a8 as a temp */ mov a6, a4 mov a4, a8 l32i a8, a1, 16 /* child_tid */ movi a2, SYS_ify (clone) /* syscall (a2 = NR_clone, a6 = clone_flags, a3 = usp, a4 = parent_tid, a5 = child_tls, a8 = child_tid) */ syscall bltz a2, SYSCALL_ERROR_LABEL beqz a2, .Lthread_start /* Fall through for parent. */ .Lpseudo_end: retw .Leinval: movi a2, -EINVAL j SYSCALL_ERROR_LABEL .Lthread_start: /* Start child thread. */ movi a0, 0 /* terminate the stack frame */ #ifdef RESET_PID /* Check and see if we need to reset the PID. */ bbsi.l a6, 16, 1f /* CLONE_THREAD = 0x00010000 */ movi a2, -1 bbsi.l a6, 8, 2f /* CLONE_VM = 0x00000100 */ movi a2, SYS_ify (getpid) syscall 2: rur a3, THREADPTR movi a4, PID_OFFSET add a4, a4, a3 s32i a2, a4, 0 movi a4, TID_OFFSET add a4, a4, a3 s32i a2, a3, 0 1: #endif /* RESET_PID */ mov a6, a9 /* load up the 'arg' parameter */ callx4 a7 /* call the user's function */ /* Call _exit. Note that any return parameter from the user's function in a6 is seen as inputs to _exit. */ movi a2, JUMPTARGET(_exit) callx4 a2 PSEUDO_END (__clone) weak_alias (__clone, clone)