/* Copyright (C) 2005, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. 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. */ #include "sysdep.h" #include <sys/syscall.h> #define _SIGNAL_H #include <bits/signum.h> /* Clone the calling process, but without copying the whole address space. The calling process is suspended until the new process exits or is replaced by a call to `execve'. Return -1 for errors, 0 to the new process, and the process ID of the new process to the old process. Note that it is important that we don't create a new stack frame for the caller. */ /* The following are defined in linux/sched.h, which unfortunately is not safe for inclusion in an assembly file. */ #define CLONE_VM 0x00000100 /* set if VM shared between processes */ #define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */ #ifndef SAVE_PID #define SAVE_PID #endif #ifndef RESTORE_PID #define RESTORE_PID #endif /* pid_t vfork(void); Implemented as __clone_syscall(CLONE_VFORK | CLONE_VM | SIGCHLD, 0) */ ENTRY (__vfork) movi a6, .Ljumptable extui a2, a0, 30, 2 /* call-size: call4/8/12 = 1/2/3 */ addx4 a4, a2, a6 /* find return address in jumptable */ l32i a4, a4, 0 add a4, a4, a6 slli a2, a2, 30 xor a3, a0, a2 /* remove call-size from return addr */ extui a5, a4, 30, 2 /* get high bits of jump target */ slli a5, a5, 30 or a3, a3, a5 /* stuff them into the return address */ xor a4, a4, a5 /* clear high bits of jump target */ or a0, a4, a2 /* create temporary return address */ retw /* "return" to .L4, .L8, or .L12 */ .align 4 .Ljumptable: .word 0 .word .L4 - .Ljumptable .word .L8 - .Ljumptable .word .L12 - .Ljumptable /* a7: return address */ .L4: mov a12, a2 mov a13, a3 SAVE_PID /* Use syscall 'clone'. Set new stack pointer to the same address. */ movi a2, SYS_ify (clone) movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD syscall RESTORE_PID movi a5, -4096 mov a6, a2 mov a2, a12 mov a3, a13 bgeu a6, a5, 1f jx a7 1: call4 .Lerr /* returns to original caller */ /* a11: return address */ .L8: mov a12, a2 mov a13, a3 mov a14, a6 SAVE_PID movi a2, SYS_ify (clone) movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD syscall RESTORE_PID movi a9, -4096 mov a10, a2 mov a2, a12 mov a3, a13 mov a6, a14 bgeu a10, a9, 1f jx a11 1: call8 .Lerr /* returns to original caller */ /* a15: return address */ .L12: mov a12, a2 mov a13, a3 mov a14, a6 SAVE_PID movi a2, SYS_ify (clone) movi a3, 0 movi a6, CLONE_VM | CLONE_VFORK | SIGCHLD syscall RESTORE_PID mov a3, a13 movi a13, -4096 mov a6, a14 mov a14, a2 mov a2, a12 bgeu a14, a13, 1f jx a15 1: call12 .Lerr /* returns to original caller */ .align 4 .Lerr: entry a1, 16 /* Restore the return address. */ extui a4, a0, 30, 2 /* get the call-size bits */ slli a4, a4, 30 slli a3, a3, 2 /* clear high bits of target address */ srli a3, a3, 2 or a0, a3, a4 /* combine them */ PSEUDO_END (__vfork) .Lpseudo_end: retw libc_hidden_def (__vfork) weak_alias (__vfork, vfork)