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 */
 88struct 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 */
115struct md_coredump {
116	struct	trapframe md_tf;
117	struct	fpstate md_fpstate;
118};
119
120#endif /* _SPARC_PCB_H_ */