xref: /illumos-gate/usr/src/lib/libc/i386/unwind/unwind_frame.S (revision 5d9d9091f564c198a760790b0bfa72c44e17912b)
1*5d9d9091SRichard Lowe/*
2*5d9d9091SRichard Lowe * CDDL HEADER START
3*5d9d9091SRichard Lowe *
4*5d9d9091SRichard Lowe * The contents of this file are subject to the terms of the
5*5d9d9091SRichard Lowe * Common Development and Distribution License (the "License").
6*5d9d9091SRichard Lowe * You may not use this file except in compliance with the License.
7*5d9d9091SRichard Lowe *
8*5d9d9091SRichard Lowe * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9*5d9d9091SRichard Lowe * or http://www.opensolaris.org/os/licensing.
10*5d9d9091SRichard Lowe * See the License for the specific language governing permissions
11*5d9d9091SRichard Lowe * and limitations under the License.
12*5d9d9091SRichard Lowe *
13*5d9d9091SRichard Lowe * When distributing Covered Code, include this CDDL HEADER in each
14*5d9d9091SRichard Lowe * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15*5d9d9091SRichard Lowe * If applicable, add the following below this CDDL HEADER, with the
16*5d9d9091SRichard Lowe * fields enclosed by brackets "[]" replaced with your own identifying
17*5d9d9091SRichard Lowe * information: Portions Copyright [yyyy] [name of copyright owner]
18*5d9d9091SRichard Lowe *
19*5d9d9091SRichard Lowe * CDDL HEADER END
20*5d9d9091SRichard Lowe */
21*5d9d9091SRichard Lowe/*
22*5d9d9091SRichard Lowe * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
23*5d9d9091SRichard Lowe * Use is subject to license terms.
24*5d9d9091SRichard Lowe */
25*5d9d9091SRichard Lowe
26*5d9d9091SRichard Lowe	.file	"unwind_frame.s"
27*5d9d9091SRichard Lowe
28*5d9d9091SRichard Lowe#include <SYS.h>
29*5d9d9091SRichard Lowe
30*5d9d9091SRichard Lowe/* Cancellation/thr_exit() stuff */
31*5d9d9091SRichard Lowe
32*5d9d9091SRichard Lowe/*
33*5d9d9091SRichard Lowe * _ex_unwind_local(void)
34*5d9d9091SRichard Lowe *
35*5d9d9091SRichard Lowe * Called only from _t_cancel().
36*5d9d9091SRichard Lowe * Unwind two frames and invoke _t_cancel(fp) again.
37*5d9d9091SRichard Lowe *
38*5d9d9091SRichard Lowe * Before this the call stack is: f4 f3 f2 f1 _t_cancel
39*5d9d9091SRichard Lowe * After this the call stack is:  f4 f3 f2 _t_cancel
40*5d9d9091SRichard Lowe *	(as if "call f1" is replaced by "call _t_cancel(fp)" in f2)
41*5d9d9091SRichard Lowe */
42*5d9d9091SRichard Lowe
43*5d9d9091SRichard Lowe	ENTRY(_ex_unwind_local)
44*5d9d9091SRichard Lowe	movl	(%ebp), %edx		/ pop first frame [ back to f1() ]
45*5d9d9091SRichard Lowe	movl	(%edx), %ebp		/ pop second frame [ back to f2() ]
46*5d9d9091SRichard Lowe	movl	4(%edx), %eax		/ save f2's return pc
47*5d9d9091SRichard Lowe	movl	%eax, (%edx)		/ mov it up for one arg
48*5d9d9091SRichard Lowe	movl	%edx, %esp		/ stack pointer at ret addr
49*5d9d9091SRichard Lowe	movl	%ebp, 4(%esp)
50*5d9d9091SRichard Lowe	jmp	_t_cancel
51*5d9d9091SRichard Lowe	SET_SIZE(_ex_unwind_local)
52*5d9d9091SRichard Lowe
53*5d9d9091SRichard Lowe/*
54*5d9d9091SRichard Lowe * _ex_clnup_handler(void *arg, void  (*clnup)(void *))
55*5d9d9091SRichard Lowe *
56*5d9d9091SRichard Lowe * Called only from _t_cancel().
57*5d9d9091SRichard Lowe * Unwind one frame, call the cleanup handler with argument arg from the
58*5d9d9091SRichard Lowe * restored frame, then jump to _t_cancel(fp) again from the restored frame.
59*5d9d9091SRichard Lowe */
60*5d9d9091SRichard Lowe
61*5d9d9091SRichard Lowe	ENTRY(_ex_clnup_handler)
62*5d9d9091SRichard Lowe	pushl	%ebp			/ save current frame pointer
63*5d9d9091SRichard Lowe	pushl	8(%esp)			/ first argument [arg]
64*5d9d9091SRichard Lowe	movl	(%ebp), %ebp		/ pop out one frame
65*5d9d9091SRichard Lowe	call	*16(%esp)		/ call handler [clnup]
66*5d9d9091SRichard Lowe	addl	$4, %esp
67*5d9d9091SRichard Lowe	popl	%eax			/ old frame pointer
68*5d9d9091SRichard Lowe	lea	4(%eax), %esp		/ stk points to old frame
69*5d9d9091SRichard Lowe	movl	%ebp, 4(%esp)		/ _t_cancel() gets frame pointer arg
70*5d9d9091SRichard Lowe	jmp	_t_cancel
71*5d9d9091SRichard Lowe	SET_SIZE(_ex_clnup_handler)
72*5d9d9091SRichard Lowe
73*5d9d9091SRichard Lowe/*
74*5d9d9091SRichard Lowe * _thrp_unwind(void *arg)
75*5d9d9091SRichard Lowe *
76*5d9d9091SRichard Lowe * Ignore the argument; jump to _t_cancel(fp) with caller's fp
77*5d9d9091SRichard Lowe */
78*5d9d9091SRichard Lowe	ENTRY(_thrp_unwind)
79*5d9d9091SRichard Lowe	movl	%ebp, 4(%esp)
80*5d9d9091SRichard Lowe	jmp	_t_cancel
81*5d9d9091SRichard Lowe	SET_SIZE(_thrp_unwind)
82