Annotation of sys/uvm/uvm_map.h, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: uvm_map.h,v 1.38 2007/04/11 12:10:42 art Exp $ */
! 2: /* $NetBSD: uvm_map.h,v 1.24 2001/02/18 21:19:08 chs Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1997 Charles D. Cranor and Washington University.
! 6: * Copyright (c) 1991, 1993, The Regents of the University of California.
! 7: *
! 8: * All rights reserved.
! 9: *
! 10: * This code is derived from software contributed to Berkeley by
! 11: * The Mach Operating System project at Carnegie-Mellon University.
! 12: *
! 13: * Redistribution and use in source and binary forms, with or without
! 14: * modification, are permitted provided that the following conditions
! 15: * are met:
! 16: * 1. Redistributions of source code must retain the above copyright
! 17: * notice, this list of conditions and the following disclaimer.
! 18: * 2. Redistributions in binary form must reproduce the above copyright
! 19: * notice, this list of conditions and the following disclaimer in the
! 20: * documentation and/or other materials provided with the distribution.
! 21: * 3. All advertising materials mentioning features or use of this software
! 22: * must display the following acknowledgement:
! 23: * This product includes software developed by Charles D. Cranor,
! 24: * Washington University, the University of California, Berkeley and
! 25: * its contributors.
! 26: * 4. Neither the name of the University nor the names of its contributors
! 27: * may be used to endorse or promote products derived from this software
! 28: * without specific prior written permission.
! 29: *
! 30: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 31: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 32: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 33: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 34: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 35: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 36: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 37: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 38: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 39: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 40: * SUCH DAMAGE.
! 41: *
! 42: * @(#)vm_map.h 8.3 (Berkeley) 3/15/94
! 43: * from: Id: uvm_map.h,v 1.1.2.3 1998/02/07 01:16:55 chs Exp
! 44: *
! 45: *
! 46: * Copyright (c) 1987, 1990 Carnegie-Mellon University.
! 47: * All rights reserved.
! 48: *
! 49: * Permission to use, copy, modify and distribute this software and
! 50: * its documentation is hereby granted, provided that both the copyright
! 51: * notice and this permission notice appear in all copies of the
! 52: * software, derivative works or modified versions, and any portions
! 53: * thereof, and that both notices appear in supporting documentation.
! 54: *
! 55: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
! 56: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
! 57: * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
! 58: *
! 59: * Carnegie Mellon requests users of this software to return to
! 60: *
! 61: * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
! 62: * School of Computer Science
! 63: * Carnegie Mellon University
! 64: * Pittsburgh PA 15213-3890
! 65: *
! 66: * any improvements or extensions that they make and grant Carnegie the
! 67: * rights to redistribute these changes.
! 68: */
! 69:
! 70: #ifndef _UVM_UVM_MAP_H_
! 71: #define _UVM_UVM_MAP_H_
! 72:
! 73: #include <sys/rwlock.h>
! 74:
! 75: #ifdef _KERNEL
! 76:
! 77: /*
! 78: * UVM_MAP_CLIP_START: ensure that the entry begins at or after
! 79: * the starting address, if it doesn't we split the entry.
! 80: *
! 81: * => map must be locked by caller
! 82: */
! 83:
! 84: #define UVM_MAP_CLIP_START(MAP,ENTRY,VA) { \
! 85: if ((VA) > (ENTRY)->start) uvm_map_clip_start(MAP,ENTRY,VA); }
! 86:
! 87: /*
! 88: * UVM_MAP_CLIP_END: ensure that the entry ends at or before
! 89: * the ending address, if it does't we split the entry.
! 90: *
! 91: * => map must be locked by caller
! 92: */
! 93:
! 94: #define UVM_MAP_CLIP_END(MAP,ENTRY,VA) { \
! 95: if ((VA) < (ENTRY)->end) uvm_map_clip_end(MAP,ENTRY,VA); }
! 96:
! 97: /*
! 98: * extract flags
! 99: */
! 100: #define UVM_EXTRACT_REMOVE 0x1 /* remove mapping from old map */
! 101: #define UVM_EXTRACT_CONTIG 0x2 /* try to keep it contig */
! 102: #define UVM_EXTRACT_QREF 0x4 /* use quick refs */
! 103: #define UVM_EXTRACT_FIXPROT 0x8 /* set prot to maxprot as we go */
! 104:
! 105: #endif /* _KERNEL */
! 106:
! 107: #include <uvm/uvm_anon.h>
! 108:
! 109: /*
! 110: * types defined:
! 111: *
! 112: * vm_map_t the high-level address map data structure.
! 113: * vm_map_entry_t an entry in an address map.
! 114: * vm_map_version_t a timestamp of a map, for use with vm_map_lookup
! 115: */
! 116:
! 117: /*
! 118: * Objects which live in maps may be either VM objects, or another map
! 119: * (called a "sharing map") which denotes read-write sharing with other maps.
! 120: *
! 121: * XXXCDC: private pager data goes here now
! 122: */
! 123:
! 124: union vm_map_object {
! 125: struct uvm_object *uvm_obj; /* UVM OBJECT */
! 126: struct vm_map *sub_map; /* belongs to another map */
! 127: };
! 128:
! 129: /*
! 130: * Address map entries consist of start and end addresses,
! 131: * a VM object (or sharing map) and offset into that object,
! 132: * and user-exported inheritance and protection information.
! 133: * Also included is control information for virtual copy operations.
! 134: */
! 135: struct vm_map_entry {
! 136: RB_ENTRY(vm_map_entry) rb_entry; /* tree information */
! 137: vaddr_t ownspace; /* free space after */
! 138: vaddr_t space; /* space in subtree */
! 139: struct vm_map_entry *prev; /* previous entry */
! 140: struct vm_map_entry *next; /* next entry */
! 141: vaddr_t start; /* start address */
! 142: vaddr_t end; /* end address */
! 143: union vm_map_object object; /* object I point to */
! 144: voff_t offset; /* offset into object */
! 145: int etype; /* entry type */
! 146: vm_prot_t protection; /* protection code */
! 147: vm_prot_t max_protection; /* maximum protection */
! 148: vm_inherit_t inheritance; /* inheritance */
! 149: int wired_count; /* can be paged if == 0 */
! 150: struct vm_aref aref; /* anonymous overlay */
! 151: int advice; /* madvise advice */
! 152: #define uvm_map_entry_stop_copy flags
! 153: u_int8_t flags; /* flags */
! 154:
! 155: #define UVM_MAP_STATIC 0x01 /* static map entry */
! 156: #define UVM_MAP_KMEM 0x02 /* from kmem entry pool */
! 157:
! 158: };
! 159:
! 160: #define VM_MAPENT_ISWIRED(entry) ((entry)->wired_count != 0)
! 161:
! 162: /*
! 163: * Maps are doubly-linked lists of map entries, kept sorted
! 164: * by address. A single hint is provided to start
! 165: * searches again from the last successful search,
! 166: * insertion, or removal.
! 167: *
! 168: * LOCKING PROTOCOL NOTES:
! 169: * -----------------------
! 170: *
! 171: * VM map locking is a little complicated. There are both shared
! 172: * and exclusive locks on maps. However, it is sometimes required
! 173: * to downgrade an exclusive lock to a shared lock, and upgrade to
! 174: * an exclusive lock again (to perform error recovery). However,
! 175: * another thread *must not* queue itself to receive an exclusive
! 176: * lock while before we upgrade back to exclusive, otherwise the
! 177: * error recovery becomes extremely difficult, if not impossible.
! 178: *
! 179: * In order to prevent this scenario, we introduce the notion of
! 180: * a `busy' map. A `busy' map is read-locked, but other threads
! 181: * attempting to write-lock wait for this flag to clear before
! 182: * entering the lock manager. A map may only be marked busy
! 183: * when the map is write-locked (and then the map must be downgraded
! 184: * to read-locked), and may only be marked unbusy by the thread
! 185: * which marked it busy (holding *either* a read-lock or a
! 186: * write-lock, the latter being gained by an upgrade).
! 187: *
! 188: * Access to the map `flags' member is controlled by the `flags_lock'
! 189: * simple lock. Note that some flags are static (set once at map
! 190: * creation time, and never changed), and thus require no locking
! 191: * to check those flags. All flags which are r/w must be set or
! 192: * cleared while the `flags_lock' is asserted. Additional locking
! 193: * requirements are:
! 194: *
! 195: * VM_MAP_PAGEABLE r/o static flag; no locking required
! 196: *
! 197: * VM_MAP_INTRSAFE r/o static flag; no locking required
! 198: *
! 199: * VM_MAP_WIREFUTURE r/w; may only be set or cleared when
! 200: * map is write-locked. may be tested
! 201: * without asserting `flags_lock'.
! 202: *
! 203: * VM_MAP_BUSY r/w; may only be set when map is
! 204: * write-locked, may only be cleared by
! 205: * thread which set it, map read-locked
! 206: * or write-locked. must be tested
! 207: * while `flags_lock' is asserted.
! 208: *
! 209: * VM_MAP_WANTLOCK r/w; may only be set when the map
! 210: * is busy, and thread is attempting
! 211: * to write-lock. must be tested
! 212: * while `flags_lock' is asserted.
! 213: */
! 214: struct vm_map {
! 215: struct pmap * pmap; /* Physical map */
! 216: struct rwlock lock; /* Lock for map data */
! 217: RB_HEAD(uvm_tree, vm_map_entry) rbhead; /* Tree for entries */
! 218: struct vm_map_entry header; /* List of entries */
! 219: int nentries; /* Number of entries */
! 220: vsize_t size; /* virtual size */
! 221: int ref_count; /* Reference count */
! 222: simple_lock_data_t ref_lock; /* Lock for ref_count field */
! 223: vm_map_entry_t hint; /* hint for quick lookups */
! 224: simple_lock_data_t hint_lock; /* lock for hint storage */
! 225: vm_map_entry_t first_free; /* First free space hint */
! 226: int flags; /* flags */
! 227: unsigned int timestamp; /* Version number */
! 228: #define min_offset header.start
! 229: #define max_offset header.end
! 230: };
! 231:
! 232: /* vm_map flags */
! 233: #define VM_MAP_PAGEABLE 0x01 /* ro: entries are pageable */
! 234: #define VM_MAP_INTRSAFE 0x02 /* ro: interrupt safe map */
! 235: #define VM_MAP_WIREFUTURE 0x04 /* rw: wire future mappings */
! 236: #define VM_MAP_BUSY 0x08 /* rw: map is busy */
! 237: #define VM_MAP_WANTLOCK 0x10 /* rw: want to write-lock */
! 238:
! 239: /* XXX: number of kernel maps and entries to statically allocate */
! 240:
! 241: #if !defined(MAX_KMAPENT)
! 242: #define MAX_KMAPENT 1024 /* XXXCDC: no crash */
! 243: #endif /* !defined MAX_KMAPENT */
! 244:
! 245: #ifdef _KERNEL
! 246: #define vm_map_modflags(map, set, clear) \
! 247: do { \
! 248: (map)->flags = ((map)->flags | (set)) & ~(clear); \
! 249: } while (0)
! 250: #endif /* _KERNEL */
! 251:
! 252: /*
! 253: * Interrupt-safe maps must also be kept on a special list,
! 254: * to assist uvm_fault() in avoiding locking problems.
! 255: */
! 256: struct vm_map_intrsafe {
! 257: struct vm_map vmi_map;
! 258: LIST_ENTRY(vm_map_intrsafe) vmi_list;
! 259: };
! 260:
! 261: /*
! 262: * handle inline options
! 263: */
! 264:
! 265: #ifdef UVM_MAP_INLINE
! 266: #define MAP_INLINE static __inline
! 267: #else
! 268: #define MAP_INLINE /* nothing */
! 269: #endif /* UVM_MAP_INLINE */
! 270:
! 271: /*
! 272: * globals:
! 273: */
! 274:
! 275: #ifdef _KERNEL
! 276:
! 277: #ifdef PMAP_GROWKERNEL
! 278: extern vaddr_t uvm_maxkaddr;
! 279: #endif
! 280:
! 281: /*
! 282: * protos: the following prototypes define the interface to vm_map
! 283: */
! 284:
! 285: MAP_INLINE
! 286: void uvm_map_deallocate(vm_map_t);
! 287:
! 288: int uvm_map_clean(vm_map_t, vaddr_t, vaddr_t, int);
! 289: void uvm_map_clip_start(vm_map_t, vm_map_entry_t, vaddr_t);
! 290: void uvm_map_clip_end(vm_map_t, vm_map_entry_t, vaddr_t);
! 291: MAP_INLINE
! 292: vm_map_t uvm_map_create(pmap_t, vaddr_t, vaddr_t, int);
! 293: int uvm_map_extract(vm_map_t, vaddr_t, vsize_t,
! 294: vm_map_t, vaddr_t *, int);
! 295: vm_map_entry_t uvm_map_findspace(vm_map_t, vaddr_t, vsize_t, vaddr_t *,
! 296: struct uvm_object *, voff_t, vsize_t, int);
! 297: vaddr_t uvm_map_hint(struct proc *, vm_prot_t);
! 298: int uvm_map_inherit(vm_map_t, vaddr_t, vaddr_t, vm_inherit_t);
! 299: int uvm_map_advice(vm_map_t, vaddr_t, vaddr_t, int);
! 300: void uvm_map_init(void);
! 301: boolean_t uvm_map_lookup_entry(vm_map_t, vaddr_t, vm_map_entry_t *);
! 302: MAP_INLINE
! 303: void uvm_map_reference(vm_map_t);
! 304: int uvm_map_replace(vm_map_t, vaddr_t, vaddr_t,
! 305: vm_map_entry_t, int);
! 306: int uvm_map_reserve(vm_map_t, vsize_t, vaddr_t, vsize_t,
! 307: vaddr_t *);
! 308: void uvm_map_setup(vm_map_t, vaddr_t, vaddr_t, int);
! 309: int uvm_map_submap(vm_map_t, vaddr_t, vaddr_t, vm_map_t);
! 310: #define uvm_unmap(_m, _s, _e) uvm_unmap_p(_m, _s, _e, 0)
! 311: MAP_INLINE
! 312: void uvm_unmap_p(vm_map_t, vaddr_t, vaddr_t, struct proc *);
! 313: void uvm_unmap_detach(vm_map_entry_t,int);
! 314: void uvm_unmap_remove(vm_map_t, vaddr_t, vaddr_t,
! 315: vm_map_entry_t *, struct proc *);
! 316:
! 317: #endif /* _KERNEL */
! 318:
! 319: /*
! 320: * VM map locking operations:
! 321: *
! 322: * These operations perform locking on the data portion of the
! 323: * map.
! 324: *
! 325: * vm_map_lock_try: try to lock a map, failing if it is already locked.
! 326: *
! 327: * vm_map_lock: acquire an exclusive (write) lock on a map.
! 328: *
! 329: * vm_map_lock_read: acquire a shared (read) lock on a map.
! 330: *
! 331: * vm_map_unlock: release an exclusive lock on a map.
! 332: *
! 333: * vm_map_unlock_read: release a shared lock on a map.
! 334: *
! 335: * vm_map_downgrade: downgrade an exclusive lock to a shared lock.
! 336: *
! 337: * vm_map_upgrade: upgrade a shared lock to an exclusive lock.
! 338: *
! 339: * vm_map_busy: mark a map as busy.
! 340: *
! 341: * vm_map_unbusy: clear busy status on a map.
! 342: *
! 343: * Note that "intrsafe" maps use only exclusive, spin locks. We simply
! 344: * use the sleep lock's interlock for this.
! 345: */
! 346:
! 347: #ifdef _KERNEL
! 348: /* XXX: clean up later */
! 349: #include <sys/time.h>
! 350: #include <sys/proc.h> /* for tsleep(), wakeup() */
! 351: #include <sys/systm.h> /* for panic() */
! 352:
! 353: static __inline boolean_t vm_map_lock_try(vm_map_t);
! 354: static __inline void vm_map_lock(vm_map_t);
! 355: extern const char vmmapbsy[];
! 356:
! 357: static __inline boolean_t
! 358: vm_map_lock_try(struct vm_map *map)
! 359: {
! 360: boolean_t rv;
! 361:
! 362: if (map->flags & VM_MAP_INTRSAFE) {
! 363: rv = TRUE;
! 364: } else {
! 365: if (map->flags & VM_MAP_BUSY) {
! 366: return (FALSE);
! 367: }
! 368: rv = (rw_enter(&map->lock, RW_WRITE|RW_NOSLEEP) == 0);
! 369: }
! 370:
! 371: if (rv)
! 372: map->timestamp++;
! 373:
! 374: return (rv);
! 375: }
! 376:
! 377: static __inline void
! 378: vm_map_lock(struct vm_map *map)
! 379: {
! 380: if (map->flags & VM_MAP_INTRSAFE)
! 381: return;
! 382:
! 383: do {
! 384: while (map->flags & VM_MAP_BUSY) {
! 385: map->flags |= VM_MAP_WANTLOCK;
! 386: tsleep(&map->flags, PVM, (char *)vmmapbsy, 0);
! 387: }
! 388: } while (rw_enter(&map->lock, RW_WRITE|RW_SLEEPFAIL) != 0);
! 389:
! 390: map->timestamp++;
! 391: }
! 392:
! 393: #define vm_map_lock_read(map) rw_enter_read(&(map)->lock)
! 394:
! 395: #define vm_map_unlock(map) \
! 396: do { \
! 397: if (((map)->flags & VM_MAP_INTRSAFE) == 0) \
! 398: rw_exit(&(map)->lock); \
! 399: } while (0)
! 400:
! 401: #define vm_map_unlock_read(map) rw_exit_read(&(map)->lock)
! 402:
! 403: #define vm_map_downgrade(map) rw_enter(&(map)->lock, RW_DOWNGRADE)
! 404:
! 405: #define vm_map_upgrade(map) \
! 406: do { \
! 407: rw_exit_read(&(map)->lock); \
! 408: rw_enter_write(&(map)->lock); \
! 409: } while (0)
! 410:
! 411: #define vm_map_busy(map) \
! 412: do { \
! 413: (map)->flags |= VM_MAP_BUSY; \
! 414: } while (0)
! 415:
! 416: #define vm_map_unbusy(map) \
! 417: do { \
! 418: int oflags; \
! 419: \
! 420: oflags = (map)->flags; \
! 421: (map)->flags &= ~(VM_MAP_BUSY|VM_MAP_WANTLOCK); \
! 422: if (oflags & VM_MAP_WANTLOCK) \
! 423: wakeup(&(map)->flags); \
! 424: } while (0)
! 425: #endif /* _KERNEL */
! 426:
! 427: /*
! 428: * Functions implemented as macros
! 429: */
! 430: #define vm_map_min(map) ((map)->min_offset)
! 431: #define vm_map_max(map) ((map)->max_offset)
! 432: #define vm_map_pmap(map) ((map)->pmap)
! 433:
! 434: #endif /* _UVM_UVM_MAP_H_ */
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