sys/boot/ia64/libski/ssc.c

   1 /*-
   2  * Copyright (c) 2001 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/boot/ia64/libski/ssc.c,v 1.4 2003/09/08 09:11:32 obrien Exp $
  27  * $DragonFly: src/sys/boot/ia64/libski/ssc.c,v 1.2 2005/01/06 08:33:11 asmodai Exp $
  28  */
  29
  30 #include <stand.h>
  31 #include "libski.h"
  32
  33 /*
  34  * Ugh... Work around a bug in the Linux version of ski for SSC_GET_RTC. The
  35  * PSR.dt register is not preserved properly and causes further memory
  36  * references to be done without translation. All we need to do is preserve
  37  * PSR.dt across the SSC call. We do this by saving and restoring psr.l
  38  * completely.
  39  */
  40 u_int64_t
  41 ssc(u_int64_t in0, u_int64_t in1, u_int64_t in2, u_int64_t in3, int which)
  42 {
  43         u_int64_t psr;
  44         u_int64_t ret0 __asm("r8");
  45
  46         __asm __volatile("mov %0=psr;;" : "=r"(psr));
  47         __asm __volatile("mov r15=%1\n\t"
  48                          "break 0x80000;;"
  49                          : "=r"(ret0)
  50                          : "r"(which), "r"(in0), "r"(in1), "r"(in2), "r"(in3));
  51         __asm __volatile("mov psr.l=%0;; srlz.d" :: "r"(psr));
  52         return ret0;
  53 }