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- /* 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)
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