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      1 /*	$NetBSD: pcb.h,v 1.9 2009/10/13 22:41:57 pooka 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_ */
    121