opnsense-src/lib/libsys/amd64/pdrfork_thread.S
Konstantin Belousov c5fc8e4fdb libsys: add pdrfork_thread() on x86
(cherry picked from commit 74a2bf1b7a7ff0c872499cb94df24713f61c872c)
2026-02-01 23:38:50 +02:00

83 lines
1.6 KiB
ArmAsm

/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright 2000 Peter Wemm <peter@FreeBSD.org>
* Copyright 2003 Alan L. Cox <alc@cs.rice.edu>
* Copyright 2026 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by
* Konstantin Belousov <kib@FreeBSD.org> under sponsorship from
* the FreeBSD Foundation.
*/
#include <machine/asm.h>
/*
* With thanks to John Dyson for the original version of this.
*/
#include <SYS.h>
/*
* %rdi %esi %rdx %rcx %r8 %r9
* pdrfork_thread(fdp, pdflags, rfflags, stack_addr, start_fnc, start_arg);
*
* fdp Pointer for the resulting fd location
* pdflags Flags as to pdfork.
* rfflags: Flags as to rfork.
* 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(pdrfork_thread)
pushq %rbx
pushq %r12
pushq %r13
movq %r8, %rbx
movq %r9, %r12
movq %rcx, %r13
/*
* Prepare and execute the thread creation syscall
*/
_SYSCALL(pdrfork)
jb 2f
/*
* Check to see if we are in the parent or child
*/
cmpl $0, %edx
jnz 1f
popq %r13
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 %r13, %rsp
movq %r12, %rdi
call *%rbx
movl %eax, %edi
/*
* Exit system call
*/
_SYSCALL(exit)
/*
* Branch here if the thread creation fails:
*/
2:
popq %r13
popq %r12
popq %rbx
jmp HIDENAME(cerror)
END(pdrfork_thread)
.section .note.GNU-stack,"",%progbits