2 * Copyright (c) 1990 The Regents of the University of California.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * $FreeBSD: src/sys/i386/i386/exception.s,v 1.65.2.3 2001/08/15 01:23:49 peter Exp $
36 #include <machine/asmacros.h>
37 #include <machine/segments.h>
38 #include <machine/lock.h>
39 #include <machine/psl.h>
40 #include <machine/trap.h>
47 * This function is what cpu_heavy_restore jumps to after a new process
48 * is created. The LWKT subsystem switches while holding a critical
49 * section and we maintain that abstraction here (e.g. because
50 * cpu_heavy_restore needs it due to PCB_*() manipulation), then get out of
51 * it before calling the initial function (typically fork_return()) and/or
52 * returning to user mode.
54 * The MP lock is not held at any point but the critcount is bumped
55 * on entry to prevent interruption of the trampoline at a bad point.
57 ENTRY(fork_trampoline)
58 movl PCPU(curthread),%eax
59 decl TD_CRITCOUNT(%eax)
62 * cpu_set_fork_handler intercepts this function call to
63 * have this call a non-return function to stay in kernel mode.
65 * initproc has its own fork handler, start_init(), which DOES
68 * The function (set in pcb_esi) gets passed two arguments,
69 * the primary parameter set in pcb_ebx and a pointer to the
71 * void (func)(int arg, struct trapframe *frame);
73 pushl %esp /* pass frame by reference */
75 call *%esi /* function */
77 /* cut from syscall */
82 * Return via doreti to handle ASTs.
87 pushl %esp /* pass by reference */