sys/arch/powerpc/include/userret.h

   1 /*      $NetBSD: userret.h,v 1.15 2007/11/06 02:52:53 simonb 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 #if defined(PPC_HAVE_FPU) || defined(ALTIVEC)
  48         struct cpu_info * const ci = curcpu();
  49 #endif
  50 #ifdef PPC_HAVE_FPU
  51         struct pcb * const pcb = lwp_getpcb(l);
  52 #endif
  53
  54         /* Invoke MI userret code */
  55         mi_userret(l);
  56
  57         frame->srr1 &= PSL_USERSRR1;    /* clear SRR1 status bits */
  58
  59         /*
  60          * If someone stole the fp or vector unit while we were away,
  61          * disable it.  Note that if the PSL FP/VEC bits aren't set, then
  62          * we don't own it.
  63          */
  64 #ifdef PPC_HAVE_FPU
  65         if ((frame->srr1 & PSL_FP) &&
  66             (l != ci->ci_fpulwp || pcb->pcb_fpcpu != ci)) {
  67                 frame->srr1 &= ~(PSL_FP|PSL_FE0|PSL_FE1);
  68         }
  69 #endif
  70 #ifdef ALTIVEC
  71         /*
  72          * We need to manually restore PSL_VEC each time we return
  73          * to user mode since PSL_VEC is not preserved in SRR1.
  74          */
  75         if (frame->srr1 & PSL_VEC) {
  76                 if (l != ci->ci_veclwp)
  77                         frame->srr1 &= ~PSL_VEC;
  78         } else {
  79                 if (l == ci->ci_veclwp)
  80                         frame->srr1 |= PSL_VEC;
  81         }
  82
  83         /*
  84          * If the new process isn't the current AltiVec process on this
  85          * CPU, we need to stop any data streams that are active (since
  86          * it will be a different address space).
  87          */
  88         if (ci->ci_veclwp != NULL && ci->ci_veclwp != l) {
  89                 __asm volatile("dssall;sync");
  90         }
  91 #endif
  92 }