HardenedBSD/lib/libsys/amd64/rfork_thread.S
Brooks Davis cdecda8da3 libc: move rfork_thread(3) to libsys
rfork_thread(3) is assembly that makes syscalls directly and uses
cerror so it belongs in libsys.

Reviewed by:	kib, emaste, imp
Pull Request:	https://github.com/freebsd/freebsd-src/pull/908
2024-02-05 20:34:56 +00:00

92 lines
2.5 KiB
ArmAsm

/*-
* Copyright (c) 2000 Peter Wemm <peter@FreeBSD.org>
* Copyright (c) 2003 Alan L. Cox <alc@cs.rice.edu>
* 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.
*/
#include <machine/asm.h>
/*
* With thanks to John Dyson for the original version of this.
*/
#include <SYS.h>
/*
* %edi %rsi %rdx %rcx
* 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)
pushq %rbx
pushq %r12
movq %rdx, %rbx
movq %rcx, %r12
/*
* Prepare and execute the thread creation syscall
*/
_SYSCALL(rfork)
jb 2f
/*
* Check to see if we are in the parent or child
*/
cmpl $0, %edx
jnz 1f
popq %r12
popq %rbx
ret
/*
* If we are in the child (new thread), then
* set-up the call to the internal subroutine. If it
* returns, then call __exit.
*/
1:
movq %rsi, %rsp
movq %r12, %rdi
call *%rbx
movl %eax, %edi
/*
* Exit system call
*/
_SYSCALL(exit)
/*
* Branch here if the thread creation fails:
*/
2:
popq %r12
popq %rbx
jmp HIDENAME(cerror)
END(rfork_thread)
.section .note.GNU-stack,"",%progbits