Home | History | Annotate | Line # | Download | only in include
pcb.h revision 1.8 
      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 #include <machine/reg.h>
     44 
     45 #ifdef notyet
     46 #define	PCB_MAXWIN	32	/* architectural limit */
     47 #else
     48 #define	PCB_MAXWIN	8	/* worried about u area sizes ... */
     49 #endif
     50 
     51 /*
     52  * SPARC Process Control Block.
     53  *
     54  * pcb_uw is positive if there are any user windows that are
     55  * are currently in the CPU windows rather than on the user
     56  * stack.  Whenever we are running in the kernel with traps
     57  * enabled, we decrement pcb_uw for each ``push'' of a CPU
     58  * register window into the stack, and we increment it for
     59  * each ``pull'' from the stack into the CPU.  (If traps are
     60  * disabled, or if we are in user mode, pcb_uw is junk.)
     61  *
     62  * To ease computing pcb_uw on traps from user mode, we keep track
     63  * of the log base 2 of the single bit that is set in %wim.
     64  *
     65  * If an overflow occurs while the associated user stack pages
     66  * are invalid (paged out), we have to store the registers
     67  * in a page that is locked in core while the process runs,
     68  * i.e., right here in the pcb.  We also need the stack pointer
     69  * for the last such window (but only the last, as the others
     70  * are in each window) and the count of windows saved.  We
     71  * cheat by having a whole window structure for that one %sp.
     72  * Thus, to save window pcb_rw[i] to memory, we write it at
     73  * pcb_rw[i + 1].rw_in[6].
     74  *
     75  * pcb_nsaved has three `kinds' of values.  If 0, it means no
     76  * registers are in the PCB (though if pcb_uw is positive,
     77  * there may be the next time you look).  If positive, it means
     78  * there are no user registers in the CPU, but there are some
     79  * saved in pcb_rw[].  As a special case, traps that needed
     80  * assistance to pull user registers from the stack also store
     81  * the registers in pcb_rw[], and set pcb_nsaved to -1.  This
     82  * special state is normally short-term: it can only last until the
     83  * trap returns, and it can never persist across entry to user code.
     84  */
     85 struct pcb {
     86 	int	pcb_sp;		/* sp (%o6) when switch() was called */
     87 	int	pcb_pc;		/* pc (%o7) when switch() was called */
     88 	int	pcb_psr;	/* %psr when switch() was called */
     89 
     90 	void *	pcb_onfault;	/* for copyin/out */
     91 
     92 	int	pcb_uw;		/* user windows inside CPU */
     93 	int	pcb_wim;	/* log2(%wim) */
     94 	int	pcb_nsaved;	/* number of windows saved in pcb */
     95 
     96 #ifdef notdef
     97 	int	pcb_winof;	/* number of window overflow traps */
     98 	int	pcb_winuf;	/* number of window underflow traps */
     99 #endif
    100 	int	pcb_pad;	/* pad to doubleword boundary */
    101 
    102 	/* the following MUST be aligned on a doubleword boundary */
    103 	struct	rwindow pcb_rw[PCB_MAXWIN];	/* saved windows */
    104 };
    105 
    106 /*
    107  * The pcb is augmented with machine-dependent additional data for
    108  * core dumps.  Note that the trapframe here is a copy of the one
    109  * from the top of the kernel stack (included here so that the kernel
    110  * stack itself need not be dumped).
    111  */
    112 struct md_coredump {
    113 	struct	trapframe md_tf;
    114 	struct	fpstate md_fpstate;
    115 };
    116