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userret.h revision 1.20 
      1 /*	$NetBSD: userret.h,v 1.20 2011/05/02 02:01:33 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 
     41 #ifdef PPC_BOOKE
     42 #include <powerpc/spr.h>
     43 #include <powerpc/booke/spr.h>
     44 #endif
     45 
     46 /*
     47  * Define the code needed before returning to user mode, for
     48  * trap and syscall.
     49  */
     50 static __inline void
     51 userret(struct lwp *l, struct trapframe *tf)
     52 {
     53 	KASSERTMSG((tf == trapframe(curlwp)),
     54 	   ("tf=%p, trapframe(curlwp)=%p\n", tf, trapframe(curlwp)));
     55 
     56 	/* Invoke MI userret code */
     57 	mi_userret(l);
     58 
     59 	tf->tf_srr1 &= PSL_USERSRR1;	/* clear SRR1 status bits */
     60 
     61 #ifdef ALTIVEC
     62 	/*
     63 	 * We need to manually restore PSL_VEC each time we return
     64 	 * to user mode since PSL_VEC isn't always preserved in SRR1.
     65 	 * We keep a copy of it in md_flags to make restoring easier.
     66 	 */
     67 	tf->tf_srr1 |= l->l_md.md_flags & PSL_VEC;
     68 #endif
     69 #ifdef PPC_BOOKE
     70 	/*
     71 	 * BookE doesn't PSL_SE but it does have a debug instruction completion
     72 	 * exception but it needs PSL_DE to fire.  Since we don't want it to
     73 	 * happen in the kernel, we must disable PSL_DE and let it get
     74 	 * restored by rfi/rfci.
     75 	 */
     76 	if (__predict_false(tf->tf_srr1 & PSL_SE)) {
     77 		extern void booke_sstep(struct trapframe *); /* ugly */
     78 		booke_sstep(tf);
     79 	}
     80 #endif
     81 }
     82