1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/* $OpenBSD: pcb.h,v 1.10 2015/05/05 02:13:47 guenther Exp $ */
/* $NetBSD: pcb.h,v 1.7 2000/12/29 17:12:05 eeh Exp $ */
/*
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)pcb.h 8.1 (Berkeley) 6/11/93
*/
#ifndef _MACHINE_PCB_H_
#define _MACHINE_PCB_H_
#include <machine/reg.h>
#ifdef notyet
#define PCB_MAXWIN 32 /* architectural limit */
#else
#define PCB_MAXWIN 8 /* worried about u area sizes ... */
#endif
/*
* SPARC Process Control Block.
*
* pcb_uw is positive if there are any user windows that are
* are currently in the CPU windows rather than on the user
* stack. Whenever we are running in the kernel with traps
* enabled, we decrement pcb_uw for each ``push'' of a CPU
* register window into the stack, and we increment it for
* each ``pull'' from the stack into the CPU. (If traps are
* disabled, or if we are in user mode, pcb_uw is junk.)
*
* To ease computing pcb_uw on traps from user mode, we keep track
* of the log base 2 of the single bit that is set in %wim.
*
* If an overflow occurs while the associated user stack pages
* are invalid (paged out), we have to store the registers
* in a page that is locked in core while the process runs,
* i.e., right here in the pcb. We also need the stack pointer
* for the last such window (but only the last, as the others
* are in each window) and the count of windows saved. We
* cheat by having a whole window structure for that one %sp.
* Thus, to save window pcb_rw[i] to memory, we write it at
* pcb_rw[i + 1].rw_in[6].
*
* pcb_nsaved has three `kinds' of values. If 0, it means no
* registers are in the PCB (though if pcb_uw is positive,
* there may be the next time you look). If positive, it means
* there are no user registers in the CPU, but there are some
* saved in pcb_rw[]. As a special case, traps that needed
* assistance to pull user registers from the stack also store
* the registers in pcb_rw[], and set pcb_nsaved to -1. This
* special state is normally short-term: it can only last until the
* trap returns, and it can never persist across entry to user code.
*/
/*
* v9 addendum:
*
* Window handling between v8 and v9 has changed somewhat. There
* is no %wim. Instead, we have a %cwp, %cansave, %canrestore,
* %cleanwin, and %otherwin. By definition:
*
* %cansave + %canrestore + %otherwin = NWINDOWS - 2
*
* In addition, %cleanwin >= %canrestore since restorable windows
* are considered clean. This means that by storing %canrestore
* and %otherwin, we should be able to compute the values of all
* the other registers.
*
* The only other register we need to save is %cwp because it cannot
* be trivially computed from the other registers. The %cwp is
* stored in the %tstate register, but if the machine was in a register
* window spill/fill handler, the value of that %cwp may be off by
* as much as 2 register windows. We will also store %cwp. [We will
* try to steal pcb_uw or pcb_nsaved for this purpose eventually.]
*
* To calculate what registers are in the pcb, start with pcb_cwp
* and proceed to (pcb_cwp - pcb_canrestore) % NWINDOWS. These should
* be saved to their appropriate register windows. The client routine
* (trap handler) is responsible for saving pcb_cwp + 1 [%o1-%o7] in
* the trap frame or on the stack.
*
*
* Even more addendum:
*
* With the new system for keeping track of register windows we don't
* care about anything other than pcb_uw which keeps track of how many
* full windows we have. As soon as a flush traps, we dump all user
* windows to the pcb, handle the fault, then restore all user windows.
*
* XXX we are using pcb_nsaved as the counter. pcb_uw is still a mask.
* change this as soon as the new scheme is debugged.
*/
struct pcb {
u_int64_t pcb_sp; /* sp (%o6) when switch() was called */
u_int64_t pcb_pc; /* pc (%o7) when switch() was called */
caddr_t pcb_onfault; /* for copyin/out */
short pcb_pstate; /* %pstate when switch() was called -- may be useful if we support multiple memory models */
char pcb_nsaved; /* number of windows saved in pcb */
/* The rest is probably not needed except for pcb_rw */
char pcb_cwp; /* %cwp when switch() was called */
char pcb_pil; /* %pil when switch() was called -- probably not needed */
const char *lastcall; /* DEBUG -- name of last system call */
u_int64_t pcb_wcookie;
/* the following MUST be aligned on a 64-bit boundary */
struct rwindow64 pcb_rw[PCB_MAXWIN]; /* saved windows */
u_int64_t pcb_rwsp[PCB_MAXWIN];
};
#ifndef _KERNEL
/* Let gdb compile. We need fancier macros to make these make sense. */
#define pcb_psr pcb_pstate
#define pcb_wim pcb_cwp
#endif /* _KERNEL */
#endif /* _MACHINE_PCB_H_ */
|
