sys/arch/sparc/include/pcb.h

   1 /*      $NetBSD: pcb.h,v 1.8 2007/03/04 06:00:44 christos Exp $ */
   2
   3 /*
   4  * Copyright (c) 1992, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This software was developed by the Computer Systems Engineering group
   8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   9  * contributed to Berkeley.
  10  *
  11  * All advertising materials mentioning features or use of this software
  12  * must display the following acknowledgement:
  13  *      This product includes software developed by the University of
  14  *      California, Lawrence Berkeley Laboratory.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  * 3. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  *      @(#)pcb.h       8.1 (Berkeley) 6/11/93
  41  */
  42
  43 #ifndef _SPARC_PCB_H_
  44 #define _SPARC_PCB_H_
  45
  46 #include <machine/reg.h>
  47
  48 #ifdef notyet
  49 #define PCB_MAXWIN      32      /* architectural limit */
  50 #else
  51 #define PCB_MAXWIN      8       /* worried about u area sizes ... */
  52 #endif
  53
  54 /*
  55  * SPARC Process Control Block.
  56  *
  57  * pcb_uw is positive if there are any user windows that are
  58  * are currently in the CPU windows rather than on the user
  59  * stack.  Whenever we are running in the kernel with traps
  60  * enabled, we decrement pcb_uw for each ``push'' of a CPU
  61  * register window into the stack, and we increment it for
  62  * each ``pull'' from the stack into the CPU.  (If traps are
  63  * disabled, or if we are in user mode, pcb_uw is junk.)
  64  *
  65  * To ease computing pcb_uw on traps from user mode, we keep track
  66  * of the log base 2 of the single bit that is set in %wim.
  67  *
  68  * If an overflow occurs while the associated user stack pages
  69  * are invalid (paged out), we have to store the registers
  70  * in a page that is locked in core while the process runs,
  71  * i.e., right here in the pcb.  We also need the stack pointer
  72  * for the last such window (but only the last, as the others
  73  * are in each window) and the count of windows saved.  We
  74  * cheat by having a whole window structure for that one %sp.
  75  * Thus, to save window pcb_rw[i] to memory, we write it at
  76  * pcb_rw[i + 1].rw_in[6].
  77  *
  78  * pcb_nsaved has three `kinds' of values.  If 0, it means no
  79  * registers are in the PCB (though if pcb_uw is positive,
  80  * there may be the next time you look).  If positive, it means
  81  * there are no user registers in the CPU, but there are some
  82  * saved in pcb_rw[].  As a special case, traps that needed
  83  * assistance to pull user registers from the stack also store
  84  * the registers in pcb_rw[], and set pcb_nsaved to -1.  This
  85  * special state is normally short-term: it can only last until the
  86  * trap returns, and it can never persist across entry to user code.
  87  */
  88 struct pcb {
  89         int     pcb_sp;         /* sp (%o6) when switch() was called */
  90         int     pcb_pc;         /* pc (%o7) when switch() was called */
  91         int     pcb_psr;        /* %psr when switch() was called */
  92
  93         void *  pcb_onfault;    /* for copyin/out */
  94
  95         int     pcb_uw;         /* user windows inside CPU */
  96         int     pcb_wim;        /* log2(%wim) */
  97         int     pcb_nsaved;     /* number of windows saved in pcb */
  98
  99 #ifdef notdef
 100         int     pcb_winof;      /* number of window overflow traps */
 101         int     pcb_winuf;      /* number of window underflow traps */
 102 #endif
 103         int     pcb_pad;        /* pad to doubleword boundary */
 104
 105         /* the following MUST be aligned on a doubleword boundary */
 106         struct  rwindow pcb_rw[PCB_MAXWIN];     /* saved windows */
 107 };
 108
 109 /*
 110  * The pcb is augmented with machine-dependent additional data for
 111  * core dumps.  Note that the trapframe here is a copy of the one
 112  * from the top of the kernel stack (included here so that the kernel
 113  * stack itself need not be dumped).
 114  */
 115 struct md_coredump {
 116         struct  trapframe md_tf;
 117         struct  fpstate md_fpstate;
 118 };
 119
 120 #endif /* _SPARC_PCB_H_ */