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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36 * from: @(#)vmparam.h 5.9 (Berkeley) 5/12/91
40 #ifndef _MACHINE_VMPARAM_H_
41 #define _MACHINE_VMPARAM_H_ 1
44 * Machine dependent constants for 386.
48 * Virtual memory related constants, all in bytes
50 #define MAXTSIZ (128UL*1024*1024) /* max text size */
52 #define DFLDSIZ (128UL*1024*1024) /* initial data size limit */
55 #define MAXDSIZ (512UL*1024*1024) /* max data size */
58 #define DFLSSIZ (8UL*1024*1024) /* initial stack size limit */
61 #define MAXSSIZ (64UL*1024*1024) /* max stack size */
64 #define SGROWSIZ (128UL*1024) /* amount to grow stack */
68 * Choose between DENSE and SPARSE based on whether lower execution time or
69 * lower kernel address space consumption is desired. Under PAE, kernel
70 * address space is often in short supply.
73 #define VM_PHYSSEG_SPARSE
75 #define VM_PHYSSEG_DENSE
79 * The number of PHYSSEG entries must be one greater than the number
80 * of phys_avail entries because the phys_avail entry that spans the
81 * largest physical address that is accessible by ISA DMA is split
82 * into two PHYSSEG entries.
84 #define VM_PHYSSEG_MAX 17
87 * Create one free page pool. Since the i386 kernel virtual address
88 * space does not include a mapping onto the machine's entire physical
89 * memory, VM_FREEPOOL_DIRECT is defined as an alias for the default
90 * pool, VM_FREEPOOL_DEFAULT.
92 #define VM_NFREEPOOL 1
93 #define VM_FREEPOOL_DEFAULT 0
94 #define VM_FREEPOOL_DIRECT 0
97 * Create up to three free page lists: VM_FREELIST_DMA32 is for physical pages
98 * that have physical addresses below 4G but are not accessible by ISA DMA,
99 * and VM_FREELIST_ISADMA is for physical pages that are accessible by ISA
102 #define VM_NFREELIST 3
103 #define VM_FREELIST_DEFAULT 0
104 #define VM_FREELIST_DMA32 1
105 #define VM_FREELIST_LOWMEM 2
107 #define VM_LOWMEM_BOUNDARY (16 << 20) /* 16MB ISA DMA limit */
110 * Always create DMA32 freelist if there is any memory above 4G.
111 * Bounce dma is extremely fragile and simultaneously intensively
114 #define VM_DMA32_NPAGES_THRESHOLD 1
117 * The largest allocation size is 2MB under PAE and 4MB otherwise.
119 #define VM_NFREEORDER_PAE 10
120 #define VM_NFREEORDER_NOPAE 11
121 #define VM_NFREEORDER_MAX VM_NFREEORDER_NOPAE
122 #define VM_NFREEORDER i386_pmap_VM_NFREEORDER
125 * Enable superpage reservations: 1 level.
127 #ifndef VM_NRESERVLEVEL
128 #define VM_NRESERVLEVEL 1
132 * Level 0 reservations consist of 512 pages when PAE pagetables are
133 * used, and 1024 pages otherwise.
135 #ifndef VM_LEVEL_0_ORDER
136 #define VM_LEVEL_0_ORDER_PAE 9
137 #define VM_LEVEL_0_ORDER_NOPAE 10
138 #define VM_LEVEL_0_ORDER_MAX VM_LEVEL_0_ORDER_NOPAE
139 #define VM_LEVEL_0_ORDER i386_pmap_VM_LEVEL_0_ORDER
141 #define VM_LEVEL_0_ORDER_MAX VM_LEVEL_0_ORDER
145 * Kernel physical load address.
148 #define KERNLOAD (8 * 1024 * 1024)
149 #endif /* !defined(KERNLOAD) */
152 * Virtual addresses of things. Derived from the page directory and
153 * page table indexes from pmap.h for precision.
154 * Because of the page that is both a PD and PT, it looks a little
155 * messy at times, but hey, we'll do anything to save a page :-)
158 #define VM_MAX_KERNEL_ADDRESS (0xffffffffU - 16 * 1024 * 1024 + 1)
160 #define VM_MIN_KERNEL_ADDRESS 0
162 #define KERNBASE KERNLOAD
164 #define UPT_MAX_ADDRESS VADDR(PTDPTDI, PTDPTDI)
165 #define UPT_MIN_ADDRESS VADDR(PTDPTDI, 0)
167 #define VM_MAXUSER_ADDRESS (0xffffffff - 4 * 1024 * 1024 + 1)
169 #define SHAREDPAGE (VM_MAXUSER_ADDRESS - PAGE_SIZE)
170 #define USRSTACK SHAREDPAGE
172 #define VM_MAX_ADDRESS VADDR(PTDPTDI, 0)
173 #define VM_MIN_ADDRESS ((vm_offset_t)0)
175 #define PMAP_TRM_MIN_ADDRESS VM_MAXUSER_ADDRESS
176 #define PMAP_TRM_MAX_ADDRESS 0xffffffff
178 #define PMAP_MAP_LOW (4 * 1024 * 1024)
181 * KVA layout. The unit of the system allocation is single PDE, which
182 * represents NBPDR bytes, aligned to NBPDR. NBPDR is 4M for non-PAE
183 * page tables, and 2M for PAE, so PAE mode requires twice as many PTDs
184 * to create the same memory map as non-PAE.
186 * 0x00000000 - 0x003fffff Transient identity map of low memory (0-4M),
187 * normally disabled to catch NULL derefs.
188 * 0x00400000 - 0x007fffff Fixed mapping of the low memory (4-8M).
189 * 0x00800000 - 0xffbfffff KERNBASE (VA) == KERNLOAD (PA), kernel
190 * text + data and all kernel maps. Managed
192 * 0xffc00000 - 0xffdfffff Recursive kernel page table mapping, pointed
193 * to by PTmap. PTD[] recursively points
195 * 0xffe00000 - 0xffffffff Kernel/User mode shared PDE, contains GDT,
196 * IDT, TSS, LDT, trampoline code and stacks.
197 * Managed by pmap_trm_alloc().
201 * How many physical pages per kmem arena virtual page.
203 #ifndef VM_KMEM_SIZE_SCALE
204 #define VM_KMEM_SIZE_SCALE (1)
208 * Optional floor (in bytes) on the size of the kmem arena.
210 #ifndef VM_KMEM_SIZE_MIN
211 #define VM_KMEM_SIZE_MIN (12 * 1024 * 1024)
215 * Optional ceiling (in bytes) on the size of the kmem arena: 40% of the
216 * kernel map rounded to the nearest multiple of the superpage size.
218 #ifndef VM_KMEM_SIZE_MAX
219 #define VM_KMEM_SIZE_MAX (((((VM_MAX_KERNEL_ADDRESS - \
220 VM_MIN_KERNEL_ADDRESS) >> (PDRSHIFT - 2)) + 5) / 10) << PDRSHIFT)
223 /* initial pagein size of beginning of executable file */
224 #ifndef VM_INITIAL_PAGEIN
225 #define VM_INITIAL_PAGEIN 16
228 #define ZERO_REGION_SIZE (64 * 1024) /* 64KB */
230 #ifndef VM_MAX_AUTOTUNE_MAXUSERS
231 #define VM_MAX_AUTOTUNE_MAXUSERS 384
237 #define SFBUF_PROCESS_PAGE
239 #define PMAP_HAS_DMAP 0
240 #define PHYS_TO_DMAP(x) ({ panic("No direct map exists"); 0; })
241 #define DMAP_TO_PHYS(x) ({ panic("No direct map exists"); 0; })
244 * No non-transparent large page support in the pmap.
246 #define PMAP_HAS_LARGEPAGES 0
249 * Need a page dump array for minidump.
251 #define MINIDUMP_PAGE_TRACKING 1
253 #endif /* _MACHINE_VMPARAM_H_ */