freebsd-dev/sys/i386/include/vmparam.h

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 * Copyright (c) 1994 John S. Dyson
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * 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.
 *
 *	from: @(#)vmparam.h	5.9 (Berkeley) 5/12/91
 * $FreeBSD$
 */


#ifndef _MACHINE_VMPARAM_H_
#define _MACHINE_VMPARAM_H_ 1

/*
 * Machine dependent constants for 386.
 */

/*
 * Virtual memory related constants, all in bytes
 */
#define	MAXTSIZ		(128UL*1024*1024)	/* max text size */
#ifndef DFLDSIZ
#define	DFLDSIZ		(128UL*1024*1024)	/* initial data size limit */
#endif
#ifndef MAXDSIZ
#define	MAXDSIZ		(512UL*1024*1024)	/* max data size */
#endif
#ifndef	DFLSSIZ
#define	DFLSSIZ		(8UL*1024*1024)		/* initial stack size limit */
#endif
#ifndef	MAXSSIZ
#define	MAXSSIZ		(64UL*1024*1024)	/* max stack size */
#endif
#ifndef SGROWSIZ
#define SGROWSIZ	(128UL*1024)		/* amount to grow stack */
#endif

/*
 * Choose between DENSE and SPARSE based on whether lower execution time or
 * lower kernel address space consumption is desired.  Under PAE, kernel
 * address space is often in short supply.
 */
#ifdef PAE
#define	VM_PHYSSEG_SPARSE
#else
#define	VM_PHYSSEG_DENSE
#endif

/*
 * The number of PHYSSEG entries must be one greater than the number
 * of phys_avail entries because the phys_avail entry that spans the
 * largest physical address that is accessible by ISA DMA is split
 * into two PHYSSEG entries. 
 */
#define	VM_PHYSSEG_MAX		17

/*
 * Create one free page pool.  Since the i386 kernel virtual address
 * space does not include a mapping onto the machine's entire physical
 * memory, VM_FREEPOOL_DIRECT is defined as an alias for the default
 * pool, VM_FREEPOOL_DEFAULT.
 */
#define	VM_NFREEPOOL		1
#define	VM_FREEPOOL_DEFAULT	0
#define	VM_FREEPOOL_DIRECT	0

/*
 * Create up to three free page lists: VM_FREELIST_DMA32 is for physical pages
 * that have physical addresses below 4G but are not accessible by ISA DMA,
 * and VM_FREELIST_ISADMA is for physical pages that are accessible by ISA
 * DMA.
 */
#define	VM_NFREELIST		3
#define	VM_FREELIST_DEFAULT	0
#define	VM_FREELIST_DMA32	1
#define	VM_FREELIST_LOWMEM	2

#define VM_LOWMEM_BOUNDARY	(16 << 20)	/* 16MB ISA DMA limit */

/*
 * Always create DMA32 freelist if there is any memory above 4G.
 * Bounce dma is extremely fragile and simultaneously intensively
 * used.
 */
#define	VM_DMA32_NPAGES_THRESHOLD	1

/*
 * The largest allocation size is 2MB under PAE and 4MB otherwise.
 */
#define	VM_NFREEORDER_PAE		10
#define	VM_NFREEORDER_NOPAE		11
#define	VM_NFREEORDER_MAX		VM_NFREEORDER_NOPAE
#define	VM_NFREEORDER			i386_pmap_VM_NFREEORDER

/*
 * Enable superpage reservations: 1 level.
 */
#ifndef	VM_NRESERVLEVEL
#define	VM_NRESERVLEVEL		1
#endif

/*
 * Level 0 reservations consist of 512 pages when PAE pagetables are
 * used, and 1024 pages otherwise.
 */
#ifndef	VM_LEVEL_0_ORDER
#define	VM_LEVEL_0_ORDER_PAE	9
#define	VM_LEVEL_0_ORDER_NOPAE	10
#define	VM_LEVEL_0_ORDER_MAX	VM_LEVEL_0_ORDER_NOPAE
#define	VM_LEVEL_0_ORDER	i386_pmap_VM_LEVEL_0_ORDER
#else
#define	VM_LEVEL_0_ORDER_MAX	VM_LEVEL_0_ORDER
#endif

/*
 * Kernel physical load address.
 */
#ifndef KERNLOAD
#define	KERNLOAD		(8 * 1024 * 1024)
#endif /* !defined(KERNLOAD) */

/*
 * Virtual addresses of things.  Derived from the page directory and
 * page table indexes from pmap.h for precision.
 * Because of the page that is both a PD and PT, it looks a little
 * messy at times, but hey, we'll do anything to save a page :-)
 */

#define VM_MAX_KERNEL_ADDRESS	(0xffffffffU - 16 * 1024 * 1024 + 1)

#define VM_MIN_KERNEL_ADDRESS	0

#define	KERNBASE		KERNLOAD

#define UPT_MAX_ADDRESS		VADDR(PTDPTDI, PTDPTDI)
#define UPT_MIN_ADDRESS		VADDR(PTDPTDI, 0)

#define VM_MAXUSER_ADDRESS	(0xffffffff - 4 * 1024 * 1024 + 1)

#define	SHAREDPAGE		(VM_MAXUSER_ADDRESS - PAGE_SIZE)
#define	USRSTACK		SHAREDPAGE

#define VM_MAX_ADDRESS		VADDR(PTDPTDI, 0)
#define VM_MIN_ADDRESS		((vm_offset_t)0)

#define	PMAP_TRM_MIN_ADDRESS	VM_MAXUSER_ADDRESS
#define	PMAP_TRM_MAX_ADDRESS	0xffffffff

#define	PMAP_MAP_LOW		(4 * 1024 * 1024)

/*
 * KVA layout.  The unit of the system allocation is single PDE, which
 * represents NBPDR bytes, aligned to NBPDR.  NBPDR is 4M for non-PAE
 * page tables, and 2M for PAE, so PAE mode requires twice as many PTDs
 * to create the same memory map as non-PAE.
 *
 * 0x00000000 - 0x003fffff	Transient identity map of low memory (0-4M),
 *				normally disabled to catch NULL derefs.
 * 0x00400000 - 0x007fffff	Fixed mapping of the low memory (4-8M).
 * 0x00800000 - 0xffbfffff	KERNBASE (VA) == KERNLOAD (PA), kernel
 *				text + data and all kernel maps.  Managed
 *				by MI VM.
 * 0xffc00000 - 0xffdfffff	Recursive kernel page table mapping, pointed
 *				to by PTmap.  PTD[] recursively points
 *				into PTmap.
 * 0xffe00000 - 0xffffffff	Kernel/User mode shared PDE, contains GDT,
 *				IDT, TSS, LDT, trampoline code and stacks.
 *				Managed by pmap_trm_alloc().
 */

/*
 * How many physical pages per kmem arena virtual page.
 */
#ifndef VM_KMEM_SIZE_SCALE
#define	VM_KMEM_SIZE_SCALE	(1)
#endif

/*
 * Optional floor (in bytes) on the size of the kmem arena.
 */
#ifndef VM_KMEM_SIZE_MIN
#define	VM_KMEM_SIZE_MIN	(12 * 1024 * 1024)
#endif

/*
 * Optional ceiling (in bytes) on the size of the kmem arena: 40% of the
 * kernel map rounded to the nearest multiple of the superpage size.
 */
#ifndef VM_KMEM_SIZE_MAX
#define	VM_KMEM_SIZE_MAX	(((((VM_MAX_KERNEL_ADDRESS - \
    VM_MIN_KERNEL_ADDRESS) >> (PDRSHIFT - 2)) + 5) / 10) << PDRSHIFT)
#endif

/* initial pagein size of beginning of executable file */
#ifndef VM_INITIAL_PAGEIN
#define	VM_INITIAL_PAGEIN	16
#endif

#define	ZERO_REGION_SIZE	(64 * 1024)	/* 64KB */

#ifndef VM_MAX_AUTOTUNE_MAXUSERS
#define VM_MAX_AUTOTUNE_MAXUSERS 384
#endif

#define	SFBUF
#define	SFBUF_MAP
#define	SFBUF_CPUSET
#define	SFBUF_PROCESS_PAGE

#define	PMAP_HAS_DMAP	0
#define	PHYS_TO_DMAP(x)	({ panic("No direct map exists"); 0; })
#define	DMAP_TO_PHYS(x)	({ panic("No direct map exists"); 0; })

#endif /* _MACHINE_VMPARAM_H_ */