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freebsd-dev/lib/libc/i386/gen/rfork_thread.S

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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
/*-
* 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.
*/
Standardize on our SCM ID style.
2002-03-23 02:44:19 +00:00
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
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
/*
* 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 8(%ebp)
Fix some rather interesting bugs that managed to not turn up in various testing and real-life applications: 1) If you returned from the thread function, you got a segv instead of calling _exit() with your return code. 2) clean up some bogus stack management. There was also an underflow on function return. 3) when making syscalls, the kernel is expecting to have to leave space for the function's return address. We need to duplicate this. It was an accident that the rfork syscall actually worked here. :-/
2000-07-29 11:34:01 +00:00
pushl $0
Use 'mov' instead of 'lea' for setting the syscall number in %eax as that is clearer about what we are actually doing. Requested by: bde
2001-11-27 20:51:26 +00:00
movl $SYS_rfork, %eax
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
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
Fix some rather interesting bugs that managed to not turn up in various testing and real-life applications: 1) If you returned from the thread function, you got a segv instead of calling _exit() with your return code. 2) clean up some bogus stack management. There was also an underflow on function return. 3) when making syscalls, the kernel is expecting to have to leave space for the function's return address. We need to duplicate this. It was an accident that the rfork syscall actually worked here. :-/
2000-07-29 11:34:01 +00:00
addl $4, %esp
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
/*
* Exit system call
*/
pushl %eax
Fix some rather interesting bugs that managed to not turn up in various testing and real-life applications: 1) If you returned from the thread function, you got a segv instead of calling _exit() with your return code. 2) clean up some bogus stack management. There was also an underflow on function return. 3) when making syscalls, the kernel is expecting to have to leave space for the function's return address. We need to duplicate this. It was an accident that the rfork syscall actually worked here. :-/
2000-07-29 11:34:01 +00:00
pushl $0
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
#ifdef SYS_exit
Use 'mov' instead of 'lea' for setting the syscall number in %eax as that is clearer about what we are actually doing. Requested by: bde
2001-11-27 20:51:26 +00:00
movl $SYS_exit, %eax
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
#else
Use 'mov' instead of 'lea' for setting the syscall number in %eax as that is clearer about what we are actually doing. Requested by: bde
2001-11-27 20:51:26 +00:00
movl $SYS_sys_exit, %eax
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
#endif
KERNCALL
/*
* Branch here if the thread creation fails:
*/
2:
PIC_PROLOGUE
jmp PIC_PLT(HIDENAME(cerror))
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