1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <sys/types.h>
30 #include <sys/systm.h>
31 #include <sys/door.h>
32 #include <sys/stack.h>
33 #include <sys/errno.h>
34 #include <sys/sysmacros.h>
35
36 int
door_finish_dispatch(caddr_t newsp)37 door_finish_dispatch(caddr_t newsp)
38 {
39 void lwp_setsp(klwp_t *, caddr_t);
40 void lwp_clear_uwin(void);
41
42 char bytes[MAX(MINFRAME, MINFRAME32)];
43 size_t count;
44 caddr_t biased_sp;
45
46 if (get_udatamodel() == DATAMODEL_NATIVE) {
47 count = MINFRAME;
48 biased_sp = newsp - STACK_BIAS;
49 } else {
50 count = MINFRAME32;
51 biased_sp = newsp;
52 }
53
54 /*
55 * We carefully zero out the stack frame we're pointing %sp at.
56 * This means that, upon returning to userland, the ins and locals
57 * will be zeroed, instead of acquiring whatever garbage was on the
58 * stack previously. In particular, this makes sure %fp is NULL,
59 * so that stack traces are properly terminated.
60 */
61 bzero(bytes, count);
62 if (copyout(bytes, newsp, count) != 0)
63 return (E2BIG);
64
65 /*
66 * There may be some user register windows stashed away
67 * because our user thread stack wasn't available during some
68 * kernel overflows. We don't care about this saved user
69 * state since we are resetting our stack. Make sure we
70 * don't try to push these registers out to our stack
71 * later on when returning from this system call.
72 *
73 * We have guaranteed that no new user windows will be stored
74 * to the pcb save area at this point since a door server
75 * thread always does a full context switch (shuttle_switch,
76 * shuttle_resume) before making itself available for a door
77 * invocation.
78 */
79 lwp_clear_uwin();
80 lwp_setsp(ttolwp(curthread), biased_sp);
81 return (0);
82 }
83
84 uintptr_t
door_final_sp(uintptr_t resultsp,size_t align,int datamodel)85 door_final_sp(uintptr_t resultsp, size_t align, int datamodel)
86 {
87 size_t minframe = (datamodel == DATAMODEL_NATIVE)?
88 MINFRAME : MINFRAME32;
89 return (P2ALIGN(resultsp - minframe, align));
90 }
91