2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1990 The Regents of the University of California.
6 * Copyright (c) 1994 John S. Dyson
9 * This code is derived from software contributed to Berkeley by
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13 * modification, are permitted provided that the following conditions
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16 * notice, this list of conditions and the following disclaimer.
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22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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36 * from: @(#)vmparam.h 5.9 (Berkeley) 5/12/91
41 #ifndef _MACHINE_VMPARAM_H_
42 #define _MACHINE_VMPARAM_H_ 1
45 * Machine dependent constants for 386.
49 * Virtual memory related constants, all in bytes
51 #define MAXTSIZ (128UL*1024*1024) /* max text size */
53 #define DFLDSIZ (128UL*1024*1024) /* initial data size limit */
56 #define MAXDSIZ (512UL*1024*1024) /* max data size */
59 #define DFLSSIZ (8UL*1024*1024) /* initial stack size limit */
62 #define MAXSSIZ (64UL*1024*1024) /* max stack size */
65 #define SGROWSIZ (128UL*1024) /* amount to grow stack */
69 * Choose between DENSE and SPARSE based on whether lower execution time or
70 * lower kernel address space consumption is desired. Under PAE, kernel
71 * address space is often in short supply.
74 #define VM_PHYSSEG_SPARSE
76 #define VM_PHYSSEG_DENSE
80 * The number of PHYSSEG entries must be one greater than the number
81 * of phys_avail entries because the phys_avail entry that spans the
82 * largest physical address that is accessible by ISA DMA is split
83 * into two PHYSSEG entries.
85 #define VM_PHYSSEG_MAX 17
88 * Create one free page pool. Since the i386 kernel virtual address
89 * space does not include a mapping onto the machine's entire physical
90 * memory, VM_FREEPOOL_DIRECT is defined as an alias for the default
91 * pool, VM_FREEPOOL_DEFAULT.
93 #define VM_NFREEPOOL 1
94 #define VM_FREEPOOL_DEFAULT 0
95 #define VM_FREEPOOL_DIRECT 0
98 * Create two free page lists: VM_FREELIST_DEFAULT is for physical
99 * pages that are above the largest physical address that is
100 * accessible by ISA DMA and VM_FREELIST_ISADMA is for physical pages
101 * that are below that address.
103 #define VM_NFREELIST 2
104 #define VM_FREELIST_DEFAULT 0
105 #define VM_FREELIST_ISADMA 1
108 * The largest allocation size is 2MB under PAE and 4MB otherwise.
111 #define VM_NFREEORDER 10
113 #define VM_NFREEORDER 11
117 * Enable superpage reservations: 1 level.
119 #ifndef VM_NRESERVLEVEL
120 #define VM_NRESERVLEVEL 1
124 * Level 0 reservations consist of 512 pages when PAE pagetables are
125 * used, and 1024 pages otherwise.
127 #ifndef VM_LEVEL_0_ORDER
128 #if defined(PAE) || defined(PAE_TABLES)
129 #define VM_LEVEL_0_ORDER 9
131 #define VM_LEVEL_0_ORDER 10
136 * Kernel physical load address.
139 #define KERNLOAD (1 << PDRSHIFT)
140 #endif /* !defined(KERNLOAD) */
143 * Virtual addresses of things. Derived from the page directory and
144 * page table indexes from pmap.h for precision.
145 * Because of the page that is both a PD and PT, it looks a little
146 * messy at times, but hey, we'll do anything to save a page :-)
149 #define VM_MAX_KERNEL_ADDRESS VADDR(KPTDI+NKPDE-1, NPTEPG-1)
151 #define VM_MIN_KERNEL_ADDRESS VADDR(PTDPTDI, PTDPTDI)
153 #define KERNBASE VADDR(KPTDI, 0)
155 #define UPT_MAX_ADDRESS VADDR(PTDPTDI, PTDPTDI)
156 #define UPT_MIN_ADDRESS VADDR(PTDPTDI, 0)
158 #define VM_MAXUSER_ADDRESS VADDR(PTDPTDI, 0)
160 #define SHAREDPAGE (VM_MAXUSER_ADDRESS - PAGE_SIZE)
161 #define USRSTACK SHAREDPAGE
163 #define VM_MAX_ADDRESS VADDR(PTDPTDI, PTDPTDI)
164 #define VM_MIN_ADDRESS ((vm_offset_t)0)
167 * How many physical pages per kmem arena virtual page.
169 #ifndef VM_KMEM_SIZE_SCALE
170 #define VM_KMEM_SIZE_SCALE (3)
174 * Optional floor (in bytes) on the size of the kmem arena.
176 #ifndef VM_KMEM_SIZE_MIN
177 #define VM_KMEM_SIZE_MIN (12 * 1024 * 1024)
181 * Optional ceiling (in bytes) on the size of the kmem arena: 40% of the
182 * kernel map rounded to the nearest multiple of the superpage size.
184 #ifndef VM_KMEM_SIZE_MAX
185 #define VM_KMEM_SIZE_MAX (((((VM_MAX_KERNEL_ADDRESS - \
186 VM_MIN_KERNEL_ADDRESS) >> (PDRSHIFT - 2)) + 5) / 10) << PDRSHIFT)
189 /* initial pagein size of beginning of executable file */
190 #ifndef VM_INITIAL_PAGEIN
191 #define VM_INITIAL_PAGEIN 16
194 #define ZERO_REGION_SIZE (64 * 1024) /* 64KB */
196 #ifndef VM_MAX_AUTOTUNE_MAXUSERS
197 #define VM_MAX_AUTOTUNE_MAXUSERS 384
203 #define SFBUF_PROCESS_PAGE
205 #define PMAP_HAS_DMAP 0
206 #define PHYS_TO_DMAP(x) ({ panic("No direct map exists"); 0; })
207 #define DMAP_TO_PHYS(x) ({ panic("No direct map exists"); 0; })
209 #endif /* _MACHINE_VMPARAM_H_ */