420 lines
13 KiB
C++
420 lines
13 KiB
C++
/* $NetBSD: vm_map.h,v 1.35 2000/03/26 20:54:48 kleink Exp $ */
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/*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)vm_map.h 8.9 (Berkeley) 5/17/95
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Authors: Avadis Tevanian, Jr., Michael Wayne Young
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* Virtual memory map module definitions.
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*/
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#ifndef _VM_MAP_
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#define _VM_MAP_
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#include <uvm/uvm_anon.h>
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/*
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* Types defined:
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*
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* vm_map_t the high-level address map data structure.
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* vm_map_entry_t an entry in an address map.
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* vm_map_version_t a timestamp of a map, for use with vm_map_lookup
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*/
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/*
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* Objects which live in maps may be either VM objects, or
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* another map (called a "sharing map") which denotes read-write
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* sharing with other maps.
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*
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* XXXCDC: private pager data goes here now
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*/
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union vm_map_object {
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struct uvm_object *uvm_obj; /* UVM OBJECT */
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struct vm_map *sub_map; /* belongs to another map */
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};
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/*
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* Address map entries consist of start and end addresses,
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* a VM object (or sharing map) and offset into that object,
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* and user-exported inheritance and protection information.
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* Also included is control information for virtual copy operations.
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*/
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struct vm_map_entry {
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struct vm_map_entry *prev; /* previous entry */
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struct vm_map_entry *next; /* next entry */
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vaddr_t start; /* start address */
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vaddr_t end; /* end address */
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union vm_map_object object; /* object I point to */
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voff_t offset; /* offset into object */
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int etype; /* entry type */
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vm_prot_t protection; /* protection code */
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vm_prot_t max_protection; /* maximum protection */
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vm_inherit_t inheritance; /* inheritance */
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int wired_count; /* can be paged if == 0 */
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struct vm_aref aref; /* anonymous overlay */
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int advice; /* madvise advice */
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#define uvm_map_entry_stop_copy flags
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u_int8_t flags; /* flags */
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#define UVM_MAP_STATIC 0x01 /* static map entry */
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};
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#define VM_MAPENT_ISWIRED(entry) ((entry)->wired_count != 0)
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/*
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* Maps are doubly-linked lists of map entries, kept sorted
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* by address. A single hint is provided to start
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* searches again from the last successful search,
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* insertion, or removal.
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*
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* LOCKING PROTOCOL NOTES:
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* -----------------------
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*
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* VM map locking is a little complicated. There are both shared
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* and exclusive locks on maps. However, it is sometimes required
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* to downgrade an exclusive lock to a shared lock, and upgrade to
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* an exclusive lock again (to perform error recovery). However,
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* another thread *must not* queue itself to receive an exclusive
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* lock while before we upgrade back to exclusive, otherwise the
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* error recovery becomes extremely difficult, if not impossible.
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*
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* In order to prevent this scenario, we introduce the notion of
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* a `busy' map. A `busy' map is read-locked, but other threads
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* attempting to write-lock wait for this flag to clear before
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* entering the lock manager. A map may only be marked busy
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* when the map is write-locked (and then the map must be downgraded
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* to read-locked), and may only be marked unbusy by the thread
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* which marked it busy (holding *either* a read-lock or a
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* write-lock, the latter being gained by an upgrade).
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*
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* Access to the map `flags' member is controlled by the `flags_lock'
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* simple lock. Note that some flags are static (set once at map
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* creation time, and never changed), and thus require no locking
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* to check those flags. All flags which are r/w must be set or
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* cleared while the `flags_lock' is asserted. Additional locking
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* requirements are:
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*
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* VM_MAP_PAGEABLE r/o static flag; no locking required
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*
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* VM_MAP_INTRSAFE r/o static flag; no locking required
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*
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* VM_MAP_WIREFUTURE r/w; may only be set or cleared when
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* map is write-locked. may be tested
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* without asserting `flags_lock'.
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*
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* VM_MAP_BUSY r/w; may only be set when map is
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* write-locked, may only be cleared by
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* thread which set it, map read-locked
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* or write-locked. must be tested
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* while `flags_lock' is asserted.
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*
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* VM_MAP_WANTLOCK r/w; may only be set when the map
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* is busy, and thread is attempting
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* to write-lock. must be tested
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* while `flags_lock' is asserted.
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*/
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struct vm_map {
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struct pmap * pmap; /* Physical map */
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lock_data_t lock; /* Lock for map data */
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struct vm_map_entry header; /* List of entries */
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int nentries; /* Number of entries */
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vsize_t size; /* virtual size */
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int ref_count; /* Reference count */
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simple_lock_data_t ref_lock; /* Lock for ref_count field */
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vm_map_entry_t hint; /* hint for quick lookups */
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simple_lock_data_t hint_lock; /* lock for hint storage */
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vm_map_entry_t first_free; /* First free space hint */
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int flags; /* flags */
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simple_lock_data_t flags_lock; /* Lock for flags field */
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unsigned int timestamp; /* Version number */
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#define min_offset header.start
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#define max_offset header.end
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};
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/* vm_map flags */
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#define VM_MAP_PAGEABLE 0x01 /* ro: entries are pageable */
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#define VM_MAP_INTRSAFE 0x02 /* ro: interrupt safe map */
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#define VM_MAP_WIREFUTURE 0x04 /* rw: wire future mappings */
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#define VM_MAP_BUSY 0x08 /* rw: map is busy */
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#define VM_MAP_WANTLOCK 0x10 /* rw: want to write-lock */
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#ifdef _KERNEL
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#define vm_map_modflags(map, set, clear) \
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do { \
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simple_lock(&(map)->flags_lock); \
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(map)->flags = ((map)->flags | (set)) & ~(clear); \
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simple_unlock(&(map)->flags_lock); \
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} while (0)
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#endif /* _KERNEL */
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/*
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* Interrupt-safe maps must also be kept on a special list,
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* to assist uvm_fault() in avoiding locking problems.
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*/
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struct vm_map_intrsafe {
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struct vm_map vmi_map;
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LIST_ENTRY(vm_map_intrsafe) vmi_list;
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};
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LIST_HEAD(vmi_list, vm_map_intrsafe);
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#ifdef _KERNEL
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extern simple_lock_data_t vmi_list_slock;
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extern struct vmi_list vmi_list;
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static __inline int vmi_list_lock __P((void));
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static __inline void vmi_list_unlock __P((int));
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static __inline int
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vmi_list_lock()
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{
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int s;
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s = splhigh();
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simple_lock(&vmi_list_slock);
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return (s);
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}
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static __inline void
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vmi_list_unlock(s)
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int s;
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{
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simple_unlock(&vmi_list_slock);
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splx(s);
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}
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#endif /* _KERNEL */
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/*
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* VM map locking operations:
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*
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* These operations perform locking on the data portion of the
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* map.
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*
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* vm_map_lock_try: try to lock a map, failing if it is already locked.
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*
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* vm_map_lock: acquire an exclusive (write) lock on a map.
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*
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* vm_map_lock_read: acquire a shared (read) lock on a map.
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*
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* vm_map_unlock: release an exclusive lock on a map.
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*
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* vm_map_unlock_read: release a shared lock on a map.
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*
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* vm_map_downgrade: downgrade an exclusive lock to a shared lock.
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*
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* vm_map_upgrade: upgrade a shared lock to an exclusive lock.
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*
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* vm_map_busy: mark a map as busy.
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*
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* vm_map_unbusy: clear busy status on a map.
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*
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* Note that "intrsafe" maps use only exclusive, spin locks. We simply
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* use the sleep lock's interlock for this.
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*/
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#ifdef _KERNEL
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/* XXX: clean up later */
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#include <sys/time.h>
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#include <sys/proc.h> /* for tsleep(), wakeup() */
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#include <sys/systm.h> /* for panic() */
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static __inline boolean_t vm_map_lock_try __P((vm_map_t));
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static __inline void vm_map_lock __P((vm_map_t));
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static __inline boolean_t
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vm_map_lock_try(map)
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vm_map_t map;
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{
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boolean_t rv;
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if (map->flags & VM_MAP_INTRSAFE)
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rv = simple_lock_try(&map->lock.lk_interlock);
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else {
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simple_lock(&map->flags_lock);
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if (map->flags & VM_MAP_BUSY) {
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simple_unlock(&map->flags_lock);
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return (FALSE);
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}
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rv = (lockmgr(&map->lock, LK_EXCLUSIVE|LK_NOWAIT|LK_INTERLOCK,
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&map->flags_lock) == 0);
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}
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if (rv)
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map->timestamp++;
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return (rv);
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}
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static __inline void
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vm_map_lock(map)
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vm_map_t map;
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{
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int error;
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if (map->flags & VM_MAP_INTRSAFE) {
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simple_lock(&map->lock.lk_interlock);
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return;
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}
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try_again:
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simple_lock(&map->flags_lock);
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if (map->flags & VM_MAP_BUSY) {
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map->flags |= VM_MAP_WANTLOCK;
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simple_unlock(&map->flags_lock);
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(void) tsleep(&map->flags, PVM, "vmmapbsy", 0);
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goto try_again;
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}
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error = lockmgr(&map->lock, LK_EXCLUSIVE|LK_SLEEPFAIL|LK_INTERLOCK,
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&map->flags_lock);
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if (error) {
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#ifdef DIAGNOSTIC
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if (error != ENOLCK)
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panic("vm_map_lock: failed to get lock");
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#endif
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goto try_again;
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}
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(map)->timestamp++;
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}
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#ifdef DIAGNOSTIC
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#define vm_map_lock_read(map) \
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do { \
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if (map->flags & VM_MAP_INTRSAFE) \
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panic("vm_map_lock_read: intrsafe map"); \
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(void) lockmgr(&(map)->lock, LK_SHARED, NULL); \
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} while (0)
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#else
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#define vm_map_lock_read(map) \
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(void) lockmgr(&(map)->lock, LK_SHARED, NULL)
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#endif
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#define vm_map_unlock(map) \
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do { \
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if ((map)->flags & VM_MAP_INTRSAFE) \
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simple_unlock(&(map)->lock.lk_interlock); \
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else \
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(void) lockmgr(&(map)->lock, LK_RELEASE, NULL); \
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} while (0)
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#define vm_map_unlock_read(map) \
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(void) lockmgr(&(map)->lock, LK_RELEASE, NULL)
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#define vm_map_downgrade(map) \
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(void) lockmgr(&(map)->lock, LK_DOWNGRADE, NULL)
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#ifdef DIAGNOSTIC
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#define vm_map_upgrade(map) \
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do { \
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if (lockmgr(&(map)->lock, LK_UPGRADE, NULL) != 0) \
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panic("vm_map_upgrade: failed to upgrade lock"); \
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} while (0)
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#else
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#define vm_map_upgrade(map) \
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(void) lockmgr(&(map)->lock, LK_UPGRADE, NULL)
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#endif
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#define vm_map_busy(map) \
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do { \
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simple_lock(&(map)->flags_lock); \
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(map)->flags |= VM_MAP_BUSY; \
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simple_unlock(&(map)->flags_lock); \
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} while (0)
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#define vm_map_unbusy(map) \
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do { \
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int oflags; \
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\
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simple_lock(&(map)->flags_lock); \
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oflags = (map)->flags; \
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(map)->flags &= ~(VM_MAP_BUSY|VM_MAP_WANTLOCK); \
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simple_unlock(&(map)->flags_lock); \
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if (oflags & VM_MAP_WANTLOCK) \
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wakeup(&(map)->flags); \
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} while (0)
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#endif /* _KERNEL */
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/*
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* Functions implemented as macros
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*/
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#define vm_map_min(map) ((map)->min_offset)
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#define vm_map_max(map) ((map)->max_offset)
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#define vm_map_pmap(map) ((map)->pmap)
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/* XXX: number of kernel maps and entries to statically allocate */
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#define MAX_KMAP 10
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#if !defined(MAX_KMAPENT)
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#if (50 + (2 * NPROC) > 1000)
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#define MAX_KMAPENT (50 + (2 * NPROC))
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#else
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#define MAX_KMAPENT 1000 /* XXXCDC: no crash */
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#endif
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#endif /* !defined MAX_KMAPENT */
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#endif /* _VM_MAP_ */
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