xref: /netbsd-src/sys/arch/powerpc/include/userret.h (revision 1b9578b8c2c1f848eeb16dabbfd7d1f0d9fdefbd)
1 /*	$NetBSD: userret.h,v 1.21 2011/06/20 06:00:46 matt Exp $	*/
2 
3 /*
4  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
5  * Copyright (C) 1995, 1996 TooLs GmbH.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by TooLs GmbH.
19  * 4. The name of TooLs GmbH may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include "opt_ppcarch.h"
35 #include "opt_altivec.h"
36 
37 #include <sys/userret.h>
38 
39 #include <powerpc/fpu.h>
40 #include <powerpc/psl.h>
41 
42 #ifdef PPC_BOOKE
43 #include <powerpc/spr.h>
44 #include <powerpc/booke/spr.h>
45 #endif
46 
47 /*
48  * Define the code needed before returning to user mode, for
49  * trap and syscall.
50  */
51 static __inline void
52 userret(struct lwp *l, struct trapframe *tf)
53 {
54 	KASSERTMSG((tf == trapframe(curlwp)),
55 	   ("tf=%p, trapframe(curlwp)=%p\n", tf, trapframe(curlwp)));
56 
57 	/* Invoke MI userret code */
58 	mi_userret(l);
59 
60 	tf->tf_srr1 &= PSL_USERSRR1;	/* clear SRR1 status bits */
61 
62 #ifdef ALTIVEC
63 	/*
64 	 * We need to manually restore PSL_VEC each time we return
65 	 * to user mode since PSL_VEC isn't always preserved in SRR1.
66 	 * We keep a copy of it in md_flags to make restoring easier.
67 	 */
68 	tf->tf_srr1 |= l->l_md.md_flags & PSL_VEC;
69 #endif
70 #ifdef PPC_BOOKE
71 	/*
72 	 * BookE doesn't PSL_SE but it does have a debug instruction completion
73 	 * exception but it needs PSL_DE to fire.  Since we don't want it to
74 	 * happen in the kernel, we must disable PSL_DE and let it get
75 	 * restored by rfi/rfci.
76 	 */
77 	if (__predict_false(tf->tf_srr1 & PSL_SE)) {
78 		extern void booke_sstep(struct trapframe *); /* ugly */
79 		booke_sstep(tf);
80 	}
81 #endif
82 }
83