xref: /onnv-gate/usr/src/uts/sparc/os/door_support.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate #include <sys/types.h>
30*0Sstevel@tonic-gate #include <sys/systm.h>
31*0Sstevel@tonic-gate #include <sys/door.h>
32*0Sstevel@tonic-gate #include <sys/stack.h>
33*0Sstevel@tonic-gate #include <sys/errno.h>
34*0Sstevel@tonic-gate #include <sys/sysmacros.h>
35*0Sstevel@tonic-gate 
36*0Sstevel@tonic-gate int
door_finish_dispatch(caddr_t newsp)37*0Sstevel@tonic-gate door_finish_dispatch(caddr_t newsp)
38*0Sstevel@tonic-gate {
39*0Sstevel@tonic-gate 	void lwp_setsp(klwp_t *, caddr_t);
40*0Sstevel@tonic-gate 	void lwp_clear_uwin(void);
41*0Sstevel@tonic-gate 
42*0Sstevel@tonic-gate 	char bytes[MAX(MINFRAME, MINFRAME32)];
43*0Sstevel@tonic-gate 	size_t count;
44*0Sstevel@tonic-gate 	caddr_t biased_sp;
45*0Sstevel@tonic-gate 
46*0Sstevel@tonic-gate 	if (get_udatamodel() == DATAMODEL_NATIVE) {
47*0Sstevel@tonic-gate 		count = MINFRAME;
48*0Sstevel@tonic-gate 		biased_sp = newsp - STACK_BIAS;
49*0Sstevel@tonic-gate 	} else {
50*0Sstevel@tonic-gate 		count = MINFRAME32;
51*0Sstevel@tonic-gate 		biased_sp = newsp;
52*0Sstevel@tonic-gate 	}
53*0Sstevel@tonic-gate 
54*0Sstevel@tonic-gate 	/*
55*0Sstevel@tonic-gate 	 * We carefully zero out the stack frame we're pointing %sp at.
56*0Sstevel@tonic-gate 	 * This means that, upon returning to userland, the ins and locals
57*0Sstevel@tonic-gate 	 * will be zeroed, instead of acquiring whatever garbage was on the
58*0Sstevel@tonic-gate 	 * stack previously.  In particular, this makes sure %fp is NULL,
59*0Sstevel@tonic-gate 	 * so that stack traces are properly terminated.
60*0Sstevel@tonic-gate 	 */
61*0Sstevel@tonic-gate 	bzero(bytes, count);
62*0Sstevel@tonic-gate 	if (copyout(bytes, newsp, count) != 0)
63*0Sstevel@tonic-gate 		return (E2BIG);
64*0Sstevel@tonic-gate 
65*0Sstevel@tonic-gate 	/*
66*0Sstevel@tonic-gate 	 * There may be some user register windows stashed away
67*0Sstevel@tonic-gate 	 * because our user thread stack wasn't available during some
68*0Sstevel@tonic-gate 	 * kernel overflows. We don't care about this saved user
69*0Sstevel@tonic-gate 	 * state since we are resetting our stack. Make sure we
70*0Sstevel@tonic-gate 	 * don't try to push these registers out to our stack
71*0Sstevel@tonic-gate 	 * later on when returning from this system call.
72*0Sstevel@tonic-gate 	 *
73*0Sstevel@tonic-gate 	 * We have guaranteed that no new user windows will be stored
74*0Sstevel@tonic-gate 	 * to the pcb save area at this point since a door server
75*0Sstevel@tonic-gate 	 * thread always does a full context switch (shuttle_switch,
76*0Sstevel@tonic-gate 	 * shuttle_resume) before making itself available for a door
77*0Sstevel@tonic-gate 	 * invocation.
78*0Sstevel@tonic-gate 	 */
79*0Sstevel@tonic-gate 	lwp_clear_uwin();
80*0Sstevel@tonic-gate 	lwp_setsp(ttolwp(curthread), biased_sp);
81*0Sstevel@tonic-gate 	return (0);
82*0Sstevel@tonic-gate }
83*0Sstevel@tonic-gate 
84*0Sstevel@tonic-gate uintptr_t
door_final_sp(uintptr_t resultsp,size_t align,int datamodel)85*0Sstevel@tonic-gate door_final_sp(uintptr_t resultsp, size_t align, int datamodel)
86*0Sstevel@tonic-gate {
87*0Sstevel@tonic-gate 	size_t minframe = (datamodel == DATAMODEL_NATIVE)?
88*0Sstevel@tonic-gate 	    MINFRAME : MINFRAME32;
89*0Sstevel@tonic-gate 	return (P2ALIGN(resultsp - minframe, align));
90*0Sstevel@tonic-gate }
91