freebsd-dev/lib/libc/i386/gen/rfork_thread.S
Peter Wemm c932e5d18f rfork(2) wrapper for simple rfork-style threads. I have lost count of
the number of times I have given this to people and got asked: why isn't
it in libc?  It is impossible to do this without assembler glue to reset
the stack for the new child process.

int rfork_thread(flags, stack_addr, start_fnc, start_arg)
int flags;                 Flags to rfork system call.  See rfork(2).
void *stack_addr;          Top of stack for thread.
int (*start_fnc)(void *);  Address of thread function to call in child.
void *start_arg;           Argument to pass to the thread function in child.

This is deliberately not documented or prototyped in includes until the
corresponding alpha version is written.
2000-07-29 07:14:04 +00:00

113 lines
2.8 KiB
ArmAsm

/*-
* Copyright (c) 2000 Peter Wemm <peter@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* With thanks to John Dyson for the original version of this.
*/
#include <SYS.h>
/*
* 8 12 16 20
* rfork_thread(flags, stack_addr, start_fnc, start_arg);
*
* flags: Flags to rfork system call. See rfork(2).
* stack_addr: Top of stack for thread.
* start_fnc: Address of thread function to call in child.
* start_arg: Argument to pass to the thread function in child.
*/
ENTRY(rfork_thread)
pushl %ebp
movl %esp, %ebp
pushl %esi
/*
* Push thread info onto the new thread's stack
*/
movl 12(%ebp), %esi # get stack addr
subl $4, %esi
movl 20(%ebp), %eax # get start argument
movl %eax, (%esi)
subl $4, %esi
movl 16(%ebp), %eax # get start thread address
movl %eax, (%esi)
/*
* Prepare and execute the thread creation syscall
*/
pushl 12(%ebp)
pushl 8(%ebp)
pushl %esi
leal SYS_rfork, %eax
KERNCALL
jb 2f
/*
* Check to see if we are in the parent or child
*/
cmpl $0, %edx
jnz 1f
addl $8, %esp
popl %esi
movl %ebp, %esp
popl %ebp
ret
.p2align 2
/*
* If we are in the child (new thread), then
* set-up the call to the internal subroutine. If it
* returns, then call __exit.
*/
1:
movl %esi,%esp
popl %eax
call *%eax
addl $12, %esp
/*
* Exit system call
*/
pushl %eax
#ifdef SYS_exit
pushl $SYS_exit
#else
pushl $SYS_sys_exit
#endif
KERNCALL
/*
* Branch here if the thread creation fails:
*/
2:
PIC_PROLOGUE
jmp PIC_PLT(HIDENAME(cerror))