xref: /freebsd/sys/i386/include/param.h (revision 44bd0e89a1c47c02639f3b2b6b9c7a5ca3aa84be)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * William Jolitz.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef _I386_INCLUDE_PARAM_H_
36 #define	_I386_INCLUDE_PARAM_H_
37 
38 #include <machine/_align.h>
39 
40 /*
41  * Machine dependent constants for Intel 386.
42  */
43 
44 #define	__HAVE_PIR
45 
46 #ifndef MACHINE
47 #define MACHINE		"i386"
48 #endif
49 #ifndef MACHINE_ARCH
50 #define	MACHINE_ARCH	"i386"
51 #endif
52 #define MID_MACHINE	MID_I386
53 
54 #ifdef SMP
55 #ifndef MAXCPU
56 #define MAXCPU		32
57 #endif
58 #else
59 #define MAXCPU		1
60 #endif
61 
62 #ifndef MAXMEMDOM
63 #define	MAXMEMDOM	1
64 #endif
65 
66 #define ALIGNBYTES	_ALIGNBYTES
67 #define ALIGN(p)	_ALIGN(p)
68 /*
69  * ALIGNED_POINTER is a boolean macro that checks whether an address
70  * is valid to fetch data elements of type t from on this architecture.
71  * This does not reflect the optimal alignment, just the possibility
72  * (within reasonable limits).
73  */
74 #define	ALIGNED_POINTER(p, t)	1
75 
76 /*
77  * CACHE_LINE_SIZE is the compile-time maximum cache line size for an
78  * architecture.  It should be used with appropriate caution.
79  */
80 #define	CACHE_LINE_SHIFT	6
81 #define	CACHE_LINE_SIZE		(1 << CACHE_LINE_SHIFT)
82 
83 #define PAGE_SHIFT	12		/* LOG2(PAGE_SIZE) */
84 #define PAGE_SIZE	(1 << PAGE_SHIFT)	/* bytes/page */
85 #define PAGE_MASK	(PAGE_SIZE - 1)
86 #define NPTEPG		(PAGE_SIZE / sizeof(pt_entry_t))
87 
88 /* Size in bytes of the page directory */
89 #define NBPTD		(NPGPTD << PAGE_SHIFT)
90 /* Number of PDEs in page directory, 2048 for PAE, 1024 for non-PAE */
91 #define NPDEPTD		(NBPTD / sizeof(pd_entry_t))
92 /* Number of PDEs in one page of the page directory, 512 vs. 1024 */
93 #define NPDEPG		(PAGE_SIZE / sizeof(pd_entry_t))
94 #define PDRMASK		(NBPDR - 1)
95 #ifndef PDRSHIFT
96 #define	PDRSHIFT	i386_pmap_PDRSHIFT
97 #endif
98 #ifndef NBPDR
99 #define NBPDR		(1 << PDRSHIFT)	/* bytes/page dir */
100 #endif
101 
102 #define	MAXPAGESIZES	2	/* maximum number of supported page sizes */
103 
104 #define IOPAGES	2		/* pages of i/o permission bitmap */
105 
106 #ifndef KSTACK_PAGES
107 #define KSTACK_PAGES 4		/* Includes pcb! */
108 #endif
109 #define KSTACK_GUARD_PAGES 1	/* pages of kstack guard; 0 disables */
110 #if KSTACK_PAGES < 4
111 #define	TD0_KSTACK_PAGES 4
112 #else
113 #define	TD0_KSTACK_PAGES KSTACK_PAGES
114 #endif
115 
116 /*
117  * Ceiling on amount of swblock kva space, can be changed via
118  * the kern.maxswzone /boot/loader.conf variable.
119  *
120  * 276 is sizeof(struct swblock), but we do not always have a definition
121  * in scope for struct swblock, so we have to hardcode it.  Each struct
122  * swblock holds metadata for 32 pages, so in theory, this is enough for
123  * 16 GB of swap.  In practice, however, the usable amount is considerably
124  * lower due to fragmentation.
125  */
126 #ifndef VM_SWZONE_SIZE_MAX
127 #define VM_SWZONE_SIZE_MAX	(276 * 128 * 1024)
128 #endif
129 
130 /*
131  * Ceiling on size of buffer cache (really only effects write queueing,
132  * the VM page cache is not effected), can be changed via
133  * the kern.maxbcache /boot/loader.conf variable.
134  *
135  * The value is equal to the size of the auto-tuned buffer map for
136  * the machine with 4GB of RAM, see vfs_bio.c:kern_vfs_bio_buffer_alloc().
137  */
138 #ifndef VM_BCACHE_SIZE_MAX
139 #define VM_BCACHE_SIZE_MAX	(7224 * 16 * 1024)
140 #endif
141 
142 /*
143  * Mach derived conversion macros
144  */
145 #define trunc_4mpage(x)		((x) & ~PDRMASK)
146 #define round_4mpage(x)		((((x)) + PDRMASK) & ~PDRMASK)
147 
148 #define i386_btop(x)		((x) >> PAGE_SHIFT)
149 #define i386_ptob(x)		((x) << PAGE_SHIFT)
150 
151 #define INKERNEL(va)		(TRUE)
152 
153 #endif /* !_I386_INCLUDE_PARAM_H_ */
154