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userret.h revision 1.13 
      1 /*	$NetBSD: userret.h,v 1.13 2006/02/16 20:17:14 perry 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_altivec.h"
     35 
     36 #include <sys/userret.h>
     37 
     38 #include <powerpc/fpu.h>
     39 
     40 /*
     41  * Define the code needed before returning to user mode, for
     42  * trap and syscall.
     43  */
     44 static __inline void
     45 userret(struct lwp *l, struct trapframe *frame)
     46 {
     47 	struct cpu_info * const ci = curcpu();
     48 #ifdef PPC_HAVE_FPU
     49 	struct pcb * const pcb = &l->l_addr->u_pcb;
     50 #endif
     51 
     52 	/* Invoke MI userret code */
     53 	mi_userret(l);
     54 
     55 	frame->srr1 &= PSL_USERSRR1;	/* clear SRR1 status bits */
     56 
     57 	/*
     58 	 * If someone stole the fp or vector unit while we were away,
     59 	 * disable it.  Note that if the PSL FP/VEC bits aren't set, then
     60 	 * we don't own it.
     61 	 */
     62 #ifdef PPC_HAVE_FPU
     63 	if ((frame->srr1 & PSL_FP) &&
     64 	    (l != ci->ci_fpulwp || pcb->pcb_fpcpu != ci)) {
     65 		frame->srr1 &= ~(PSL_FP|PSL_FE0|PSL_FE1);
     66 	}
     67 #endif
     68 #ifdef ALTIVEC
     69 	/*
     70 	 * We need to manually restore PSL_VEC each time we return
     71 	 * to user mode since PSL_VEC is not preserved in SRR1.
     72 	 */
     73 	if (frame->srr1 & PSL_VEC) {
     74 		if (l != ci->ci_veclwp)
     75 			frame->srr1 &= ~PSL_VEC;
     76 	} else {
     77 		if (l == ci->ci_veclwp)
     78 			frame->srr1 |= PSL_VEC;
     79 	}
     80 
     81 	/*
     82 	 * If the new process isn't the current AltiVec process on this
     83 	 * CPU, we need to stop any data streams that are active (since
     84 	 * it will be a different address space).
     85 	 */
     86 	if (ci->ci_veclwp != NULL && ci->ci_veclwp != l) {
     87 		__asm volatile("dssall;sync");
     88 	}
     89 #endif
     90 
     91 	ci->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
     92 }
     93