/* * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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: @(#)vm_map.c 8.3 (Berkeley) 1/12/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Authors: Avadis Tevanian, Jr., Michael Wayne Young * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. * * $FreeBSD: src/sys/vm/vm_map.c,v 1.187.2.19 2003/05/27 00:47:02 alc Exp $ * $DragonFly: src/sys/vm/vm_map.c,v 1.56 2007/04/29 18:25:41 dillon Exp $ */ /* * Virtual memory mapping module. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Virtual memory maps provide for the mapping, protection, * and sharing of virtual memory objects. In addition, * this module provides for an efficient virtual copy of * memory from one map to another. * * Synchronization is required prior to most operations. * * Maps consist of an ordered doubly-linked list of simple * entries; a single hint is used to speed up lookups. * * Since portions of maps are specified by start/end addresses, * which may not align with existing map entries, all * routines merely "clip" entries to these start/end values. * [That is, an entry is split into two, bordering at a * start or end value.] Note that these clippings may not * always be necessary (as the two resulting entries are then * not changed); however, the clipping is done for convenience. * * As mentioned above, virtual copy operations are performed * by copying VM object references from one map to * another, and then marking both regions as copy-on-write. */ static void vmspace_terminate(struct vmspace *vm); static void vmspace_dtor(void *obj, void *private); MALLOC_DEFINE(M_VMSPACE, "vmspace", "vmspace objcache backingstore"); struct sysref_class vmspace_sysref_class = { .name = "vmspace", .mtype = M_VMSPACE, .proto = SYSREF_PROTO_VMSPACE, .offset = offsetof(struct vmspace, vm_sysref), .objsize = sizeof(struct vmspace), .mag_capacity = 32, .flags = SRC_MANAGEDINIT, .dtor = vmspace_dtor, .ops = { .terminate = (sysref_terminate_func_t)vmspace_terminate } }; #define VMEPERCPU 2 static struct vm_zone mapentzone_store, mapzone_store; static vm_zone_t mapentzone, mapzone; static struct vm_object mapentobj, mapobj; static struct vm_map_entry map_entry_init[MAX_MAPENT]; static struct vm_map_entry cpu_map_entry_init[MAXCPU][VMEPERCPU]; static struct vm_map map_init[MAX_KMAP]; static void vm_map_entry_shadow(vm_map_entry_t entry); static vm_map_entry_t vm_map_entry_create(vm_map_t map, int *); static void vm_map_entry_dispose (vm_map_t map, vm_map_entry_t entry, int *); static void _vm_map_clip_end (vm_map_t, vm_map_entry_t, vm_offset_t, int *); static void _vm_map_clip_start (vm_map_t, vm_map_entry_t, vm_offset_t, int *); static void vm_map_entry_delete (vm_map_t, vm_map_entry_t, int *); static void vm_map_entry_unwire (vm_map_t, vm_map_entry_t); static void vm_map_copy_entry (vm_map_t, vm_map_t, vm_map_entry_t, vm_map_entry_t); static void vm_map_split (vm_map_entry_t); static void vm_map_unclip_range (vm_map_t map, vm_map_entry_t start_entry, vm_offset_t start, vm_offset_t end, int *count, int flags); /* * vm_map_startup: * * Initialize the vm_map module. Must be called before * any other vm_map routines. * * Map and entry structures are allocated from the general * purpose memory pool with some exceptions: * * - The kernel map and kmem submap are allocated statically. * - Kernel map entries are allocated out of a static pool. * * These restrictions are necessary since malloc() uses the * maps and requires map entries. */ void vm_map_startup(void) { mapzone = &mapzone_store; zbootinit(mapzone, "MAP", sizeof (struct vm_map), map_init, MAX_KMAP); mapentzone = &mapentzone_store; zbootinit(mapentzone, "MAP ENTRY", sizeof (struct vm_map_entry), map_entry_init, MAX_MAPENT); } /* * vm_init2 - called prior to any vmspace allocations */ void vm_init2(void) { zinitna(mapentzone, &mapentobj, NULL, 0, 0, ZONE_USE_RESERVE | ZONE_SPECIAL, 1); zinitna(mapzone, &mapobj, NULL, 0, 0, 0, 1); pmap_init2(); vm_object_init2(); } /* * Red black tree functions */ static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b); RB_GENERATE(vm_map_rb_tree, vm_map_entry, rb_entry, rb_vm_map_compare); /* a->start is address, and the only field has to be initialized */ static int rb_vm_map_compare(vm_map_entry_t a, vm_map_entry_t b) { if (a->start < b->start) return(-1); else if (a->start > b->start) return(1); return(0); } /* * Allocate a vmspace structure, including a vm_map and pmap. * Initialize numerous fields. While the initial allocation is zerod, * subsequence reuse from the objcache leaves elements of the structure * intact (particularly the pmap), so portions must be zerod. * * The structure is not considered activated until we call sysref_activate(). */ struct vmspace * vmspace_alloc(vm_offset_t min, vm_offset_t max) { struct vmspace *vm; vm = sysref_alloc(&vmspace_sysref_class); bzero(&vm->vm_startcopy, (char *)&vm->vm_endcopy - (char *)&vm->vm_startcopy); vm_map_init(&vm->vm_map, min, max, NULL); pmap_pinit(vmspace_pmap(vm)); /* (some fields reused) */ vm->vm_map.pmap = vmspace_pmap(vm); /* XXX */ vm->vm_shm = NULL; vm->vm_exitingcnt = 0; cpu_vmspace_alloc(vm); sysref_activate(&vm->vm_sysref); return (vm); } /* * dtor function - Some elements of the pmap are retained in the * free-cached vmspaces to improve performance. We have to clean them up * here before returning the vmspace to the memory pool. */ static void vmspace_dtor(void *obj, void *private) { struct vmspace *vm = obj; pmap_puninit(vmspace_pmap(vm)); } /* * Called in two cases: * * (1) When the last sysref is dropped, but exitingcnt might still be * non-zero. * * (2) When there are no sysrefs (i.e. refcnt is negative) left and the * exitingcnt becomes zero * * sysref will not scrap the object until we call sysref_put() once more * after the last ref has been dropped. */ static void vmspace_terminate(struct vmspace *vm) { int count; /* * If exitingcnt is non-zero we can't get rid of the entire vmspace * yet, but we can scrap user memory. */ if (vm->vm_exitingcnt) { shmexit(vm); pmap_remove_pages(vmspace_pmap(vm), VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS); vm_map_remove(&vm->vm_map, VM_MIN_USER_ADDRESS, VM_MAX_USER_ADDRESS); return; } cpu_vmspace_free(vm); /* * Make sure any SysV shm is freed, it might not have in * exit1() */ shmexit(vm); KKASSERT(vm->vm_upcalls == NULL); /* * Lock the map, to wait out all other references to it. * Delete all of the mappings and pages they hold, then call * the pmap module to reclaim anything left. */ count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(&vm->vm_map); vm_map_delete(&vm->vm_map, vm->vm_map.min_offset, vm->vm_map.max_offset, &count); vm_map_unlock(&vm->vm_map); vm_map_entry_release(count); pmap_release(vmspace_pmap(vm)); sysref_put(&vm->vm_sysref); } /* * This is called in the wait*() handling code. The vmspace can be terminated * after the last wait is finished using it. */ void vmspace_exitfree(struct proc *p) { struct vmspace *vm; vm = p->p_vmspace; p->p_vmspace = NULL; if (--vm->vm_exitingcnt == 0 && sysref_isinactive(&vm->vm_sysref)) vmspace_terminate(vm); } /* * vmspace_swap_count() * * Swap useage is determined by taking the proportional swap used by * VM objects backing the VM map. To make up for fractional losses, * if the VM object has any swap use at all the associated map entries * count for at least 1 swap page. */ int vmspace_swap_count(struct vmspace *vmspace) { vm_map_t map = &vmspace->vm_map; vm_map_entry_t cur; vm_object_t object; int count = 0; int n; for (cur = map->header.next; cur != &map->header; cur = cur->next) { switch(cur->maptype) { case VM_MAPTYPE_NORMAL: case VM_MAPTYPE_VPAGETABLE: if ((object = cur->object.vm_object) == NULL) break; if (object->type != OBJT_SWAP) break; n = (cur->end - cur->start) / PAGE_SIZE; if (object->un_pager.swp.swp_bcount) { count += object->un_pager.swp.swp_bcount * SWAP_META_PAGES * n / object->size + 1; } break; default: break; } } return(count); } /* * vmspace_anonymous_count() * * Calculate the approximate number of anonymous pages in use by * this vmspace. To make up for fractional losses, we count each * VM object as having at least 1 anonymous page. */ int vmspace_anonymous_count(struct vmspace *vmspace) { vm_map_t map = &vmspace->vm_map; vm_map_entry_t cur; vm_object_t object; int count = 0; for (cur = map->header.next; cur != &map->header; cur = cur->next) { switch(cur->maptype) { case VM_MAPTYPE_NORMAL: case VM_MAPTYPE_VPAGETABLE: if ((object = cur->object.vm_object) == NULL) break; if (object->type != OBJT_DEFAULT && object->type != OBJT_SWAP) { break; } count += object->resident_page_count; break; default: break; } } return(count); } /* * vm_map_create: * * Creates and returns a new empty VM map with * the given physical map structure, and having * the given lower and upper address bounds. */ vm_map_t vm_map_create(vm_map_t result, pmap_t pmap, vm_offset_t min, vm_offset_t max) { if (result == NULL) result = zalloc(mapzone); vm_map_init(result, min, max, pmap); return (result); } /* * Initialize an existing vm_map structure * such as that in the vmspace structure. * The pmap is set elsewhere. */ void vm_map_init(struct vm_map *map, vm_offset_t min, vm_offset_t max, pmap_t pmap) { map->header.next = map->header.prev = &map->header; RB_INIT(&map->rb_root); map->nentries = 0; map->size = 0; map->system_map = 0; map->infork = 0; map->min_offset = min; map->max_offset = max; map->pmap = pmap; map->first_free = &map->header; map->hint = &map->header; map->timestamp = 0; lockinit(&map->lock, "thrd_sleep", 0, 0); } /* * Shadow the vm_map_entry's object. This typically needs to be done when * a write fault is taken on an entry which had previously been cloned by * fork(). The shared object (which might be NULL) must become private so * we add a shadow layer above it. * * Object allocation for anonymous mappings is defered as long as possible. * When creating a shadow, however, the underlying object must be instantiated * so it can be shared. * * If the map segment is governed by a virtual page table then it is * possible to address offsets beyond the mapped area. Just allocate * a maximally sized object for this case. */ static void vm_map_entry_shadow(vm_map_entry_t entry) { if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { vm_object_shadow(&entry->object.vm_object, &entry->offset, 0x7FFFFFFF); /* XXX */ } else { vm_object_shadow(&entry->object.vm_object, &entry->offset, atop(entry->end - entry->start)); } entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; } /* * Allocate an object for a vm_map_entry. * * Object allocation for anonymous mappings is defered as long as possible. * This function is called when we can defer no longer, generally when a map * entry might be split or forked or takes a page fault. * * If the map segment is governed by a virtual page table then it is * possible to address offsets beyond the mapped area. Just allocate * a maximally sized object for this case. */ void vm_map_entry_allocate_object(vm_map_entry_t entry) { vm_object_t obj; if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { obj = vm_object_allocate(OBJT_DEFAULT, 0x7FFFFFFF); /* XXX */ } else { obj = vm_object_allocate(OBJT_DEFAULT, atop(entry->end - entry->start)); } entry->object.vm_object = obj; entry->offset = 0; } /* * vm_map_entry_reserve_cpu_init: * * Set an initial negative count so the first attempt to reserve * space preloads a bunch of vm_map_entry's for this cpu. Also * pre-allocate 2 vm_map_entries which will be needed by zalloc() to * map a new page for vm_map_entry structures. SMP systems are * particularly sensitive. * * This routine is called in early boot so we cannot just call * vm_map_entry_reserve(). * * May be called for a gd other then mycpu, but may only be called * during early boot. */ void vm_map_entry_reserve_cpu_init(globaldata_t gd) { vm_map_entry_t entry; int i; gd->gd_vme_avail -= MAP_RESERVE_COUNT * 2; entry = &cpu_map_entry_init[gd->gd_cpuid][0]; for (i = 0; i < VMEPERCPU; ++i, ++entry) { entry->next = gd->gd_vme_base; gd->gd_vme_base = entry; } } /* * vm_map_entry_reserve: * * Reserves vm_map_entry structures so code later on can manipulate * map_entry structures within a locked map without blocking trying * to allocate a new vm_map_entry. */ int vm_map_entry_reserve(int count) { struct globaldata *gd = mycpu; vm_map_entry_t entry; crit_enter(); /* * Make sure we have enough structures in gd_vme_base to handle * the reservation request. */ while (gd->gd_vme_avail < count) { entry = zalloc(mapentzone); entry->next = gd->gd_vme_base; gd->gd_vme_base = entry; ++gd->gd_vme_avail; } gd->gd_vme_avail -= count; crit_exit(); return(count); } /* * vm_map_entry_release: * * Releases previously reserved vm_map_entry structures that were not * used. If we have too much junk in our per-cpu cache clean some of * it out. */ void vm_map_entry_release(int count) { struct globaldata *gd = mycpu; vm_map_entry_t entry; crit_enter(); gd->gd_vme_avail += count; while (gd->gd_vme_avail > MAP_RESERVE_SLOP) { entry = gd->gd_vme_base; KKASSERT(entry != NULL); gd->gd_vme_base = entry->next; --gd->gd_vme_avail; crit_exit(); zfree(mapentzone, entry); crit_enter(); } crit_exit(); } /* * vm_map_entry_kreserve: * * Reserve map entry structures for use in kernel_map itself. These * entries have *ALREADY* been reserved on a per-cpu basis when the map * was inited. This function is used by zalloc() to avoid a recursion * when zalloc() itself needs to allocate additional kernel memory. * * This function works like the normal reserve but does not load the * vm_map_entry cache (because that would result in an infinite * recursion). Note that gd_vme_avail may go negative. This is expected. * * Any caller of this function must be sure to renormalize after * potentially eating entries to ensure that the reserve supply * remains intact. */ int vm_map_entry_kreserve(int count) { struct globaldata *gd = mycpu; crit_enter(); gd->gd_vme_avail -= count; crit_exit(); KASSERT(gd->gd_vme_base != NULL, ("no reserved entries left, gd_vme_avail = %d\n", gd->gd_vme_avail)); return(count); } /* * vm_map_entry_krelease: * * Release previously reserved map entries for kernel_map. We do not * attempt to clean up like the normal release function as this would * cause an unnecessary (but probably not fatal) deep procedure call. */ void vm_map_entry_krelease(int count) { struct globaldata *gd = mycpu; crit_enter(); gd->gd_vme_avail += count; crit_exit(); } /* * vm_map_entry_create: [ internal use only ] * * Allocates a VM map entry for insertion. No entry fields are filled * in. * * This routine may be called from an interrupt thread but not a FAST * interrupt. This routine may recurse the map lock. */ static vm_map_entry_t vm_map_entry_create(vm_map_t map, int *countp) { struct globaldata *gd = mycpu; vm_map_entry_t entry; KKASSERT(*countp > 0); --*countp; crit_enter(); entry = gd->gd_vme_base; KASSERT(entry != NULL, ("gd_vme_base NULL! count %d", *countp)); gd->gd_vme_base = entry->next; crit_exit(); return(entry); } /* * vm_map_entry_dispose: [ internal use only ] * * Dispose of a vm_map_entry that is no longer being referenced. This * function may be called from an interrupt. */ static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry, int *countp) { struct globaldata *gd = mycpu; KKASSERT(map->hint != entry); KKASSERT(map->first_free != entry); ++*countp; crit_enter(); entry->next = gd->gd_vme_base; gd->gd_vme_base = entry; crit_exit(); } /* * vm_map_entry_{un,}link: * * Insert/remove entries from maps. */ static __inline void vm_map_entry_link(vm_map_t map, vm_map_entry_t after_where, vm_map_entry_t entry) { map->nentries++; entry->prev = after_where; entry->next = after_where->next; entry->next->prev = entry; after_where->next = entry; if (vm_map_rb_tree_RB_INSERT(&map->rb_root, entry)) panic("vm_map_entry_link: dup addr map %p ent %p", map, entry); } static __inline void vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry) { vm_map_entry_t prev; vm_map_entry_t next; if (entry->eflags & MAP_ENTRY_IN_TRANSITION) panic("vm_map_entry_unlink: attempt to mess with locked entry! %p", entry); prev = entry->prev; next = entry->next; next->prev = prev; prev->next = next; vm_map_rb_tree_RB_REMOVE(&map->rb_root, entry); map->nentries--; } /* * vm_map_lookup_entry: [ internal use only ] * * Finds the map entry containing (or * immediately preceding) the specified address * in the given map; the entry is returned * in the "entry" parameter. The boolean * result indicates whether the address is * actually contained in the map. */ boolean_t vm_map_lookup_entry(vm_map_t map, vm_offset_t address, vm_map_entry_t *entry /* OUT */) { vm_map_entry_t tmp; vm_map_entry_t last; #if 0 /* * XXX TEMPORARILY DISABLED. For some reason our attempt to revive * the hint code with the red-black lookup meets with system crashes * and lockups. We do not yet know why. * * It is possible that the problem is related to the setting * of the hint during map_entry deletion, in the code specified * at the GGG comment later on in this file. */ /* * Quickly check the cached hint, there's a good chance of a match. */ if (map->hint != &map->header) { tmp = map->hint; if (address >= tmp->start && address < tmp->end) { *entry = tmp; return(TRUE); } } #endif /* * Locate the record from the top of the tree. 'last' tracks the * closest prior record and is returned if no match is found, which * in binary tree terms means tracking the most recent right-branch * taken. If there is no prior record, &map->header is returned. */ last = &map->header; tmp = RB_ROOT(&map->rb_root); while (tmp) { if (address >= tmp->start) { if (address < tmp->end) { *entry = tmp; map->hint = tmp; return(TRUE); } last = tmp; tmp = RB_RIGHT(tmp, rb_entry); } else { tmp = RB_LEFT(tmp, rb_entry); } } *entry = last; return (FALSE); } /* * vm_map_insert: * * Inserts the given whole VM object into the target * map at the specified address range. The object's * size should match that of the address range. * * Requires that the map be locked, and leaves it so. Requires that * sufficient vm_map_entry structures have been reserved and tracks * the use via countp. * * If object is non-NULL, ref count must be bumped by caller * prior to making call to account for the new entry. */ int vm_map_insert(vm_map_t map, int *countp, vm_object_t object, vm_ooffset_t offset, vm_offset_t start, vm_offset_t end, vm_maptype_t maptype, vm_prot_t prot, vm_prot_t max, int cow) { vm_map_entry_t new_entry; vm_map_entry_t prev_entry; vm_map_entry_t temp_entry; vm_eflags_t protoeflags; /* * Check that the start and end points are not bogus. */ if ((start < map->min_offset) || (end > map->max_offset) || (start >= end)) return (KERN_INVALID_ADDRESS); /* * Find the entry prior to the proposed starting address; if it's part * of an existing entry, this range is bogus. */ if (vm_map_lookup_entry(map, start, &temp_entry)) return (KERN_NO_SPACE); prev_entry = temp_entry; /* * Assert that the next entry doesn't overlap the end point. */ if ((prev_entry->next != &map->header) && (prev_entry->next->start < end)) return (KERN_NO_SPACE); protoeflags = 0; if (cow & MAP_COPY_ON_WRITE) protoeflags |= MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY; if (cow & MAP_NOFAULT) { protoeflags |= MAP_ENTRY_NOFAULT; KASSERT(object == NULL, ("vm_map_insert: paradoxical MAP_NOFAULT request")); } if (cow & MAP_DISABLE_SYNCER) protoeflags |= MAP_ENTRY_NOSYNC; if (cow & MAP_DISABLE_COREDUMP) protoeflags |= MAP_ENTRY_NOCOREDUMP; if (cow & MAP_IS_STACK) protoeflags |= MAP_ENTRY_STACK; if (object) { /* * When object is non-NULL, it could be shared with another * process. We have to set or clear OBJ_ONEMAPPING * appropriately. */ if ((object->ref_count > 1) || (object->shadow_count != 0)) { vm_object_clear_flag(object, OBJ_ONEMAPPING); } } else if ((prev_entry != &map->header) && (prev_entry->eflags == protoeflags) && (prev_entry->end == start) && (prev_entry->wired_count == 0) && prev_entry->maptype == maptype && ((prev_entry->object.vm_object == NULL) || vm_object_coalesce(prev_entry->object.vm_object, OFF_TO_IDX(prev_entry->offset), (vm_size_t)(prev_entry->end - prev_entry->start), (vm_size_t)(end - prev_entry->end)))) { /* * We were able to extend the object. Determine if we * can extend the previous map entry to include the * new range as well. */ if ((prev_entry->inheritance == VM_INHERIT_DEFAULT) && (prev_entry->protection == prot) && (prev_entry->max_protection == max)) { map->size += (end - prev_entry->end); prev_entry->end = end; vm_map_simplify_entry(map, prev_entry, countp); return (KERN_SUCCESS); } /* * If we can extend the object but cannot extend the * map entry, we have to create a new map entry. We * must bump the ref count on the extended object to * account for it. object may be NULL. */ object = prev_entry->object.vm_object; offset = prev_entry->offset + (prev_entry->end - prev_entry->start); vm_object_reference(object); } /* * NOTE: if conditionals fail, object can be NULL here. This occurs * in things like the buffer map where we manage kva but do not manage * backing objects. */ /* * Create a new entry */ new_entry = vm_map_entry_create(map, countp); new_entry->start = start; new_entry->end = end; new_entry->maptype = maptype; new_entry->eflags = protoeflags; new_entry->object.vm_object = object; new_entry->offset = offset; new_entry->aux.master_pde = 0; new_entry->inheritance = VM_INHERIT_DEFAULT; new_entry->protection = prot; new_entry->max_protection = max; new_entry->wired_count = 0; /* * Insert the new entry into the list */ vm_map_entry_link(map, prev_entry, new_entry); map->size += new_entry->end - new_entry->start; /* * Update the free space hint */ if ((map->first_free == prev_entry) && (prev_entry->end >= new_entry->start)) { map->first_free = new_entry; } #if 0 /* * Temporarily removed to avoid MAP_STACK panic, due to * MAP_STACK being a huge hack. Will be added back in * when MAP_STACK (and the user stack mapping) is fixed. */ /* * It may be possible to simplify the entry */ vm_map_simplify_entry(map, new_entry, countp); #endif /* * Try to pre-populate the page table. Mappings governed by virtual * page tables cannot be prepopulated without a lot of work, so * don't try. */ if ((cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) && maptype != VM_MAPTYPE_VPAGETABLE) { pmap_object_init_pt(map->pmap, start, prot, object, OFF_TO_IDX(offset), end - start, cow & MAP_PREFAULT_PARTIAL); } return (KERN_SUCCESS); } /* * Find sufficient space for `length' bytes in the given map, starting at * `start'. The map must be locked. Returns 0 on success, 1 on no space. * * This function will returned an arbitrarily aligned pointer. If no * particular alignment is required you should pass align as 1. Note that * the map may return PAGE_SIZE aligned pointers if all the lengths used in * the map are a multiple of PAGE_SIZE, even if you pass a smaller align * argument. * * 'align' should be a power of 2 but is not required to be. */ int vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, vm_offset_t align, int flags, vm_offset_t *addr) { vm_map_entry_t entry, next; vm_offset_t end; vm_offset_t align_mask; if (start < map->min_offset) start = map->min_offset; if (start > map->max_offset) return (1); /* * If the alignment is not a power of 2 we will have to use * a mod/division, set align_mask to a special value. */ if ((align | (align - 1)) + 1 != (align << 1)) align_mask = (vm_offset_t)-1; else align_mask = align - 1; retry: /* * Look for the first possible address; if there's already something * at this address, we have to start after it. */ if (start == map->min_offset) { if ((entry = map->first_free) != &map->header) start = entry->end; } else { vm_map_entry_t tmp; if (vm_map_lookup_entry(map, start, &tmp)) start = tmp->end; entry = tmp; } /* * Look through the rest of the map, trying to fit a new region in the * gap between existing regions, or after the very last region. */ for (;; start = (entry = next)->end) { /* * Adjust the proposed start by the requested alignment, * be sure that we didn't wrap the address. */ if (align_mask == (vm_offset_t)-1) end = ((start + align - 1) / align) * align; else end = (start + align_mask) & ~align_mask; if (end < start) return (1); start = end; /* * Find the end of the proposed new region. Be sure we didn't * go beyond the end of the map, or wrap around the address. * Then check to see if this is the last entry or if the * proposed end fits in the gap between this and the next * entry. */ end = start + length; if (end > map->max_offset || end < start) return (1); next = entry->next; /* * If the next entry's start address is beyond the desired * end address we may have found a good entry. * * If the next entry is a stack mapping we do not map into * the stack's reserved space. * * XXX continue to allow mapping into the stack's reserved * space if doing a MAP_STACK mapping inside a MAP_STACK * mapping, for backwards compatibility. But the caller * really should use MAP_STACK | MAP_TRYFIXED if they * want to do that. */ if (next == &map->header) break; if (next->start >= end) { if ((next->eflags & MAP_ENTRY_STACK) == 0) break; if (flags & MAP_STACK) break; if (next->start - next->aux.avail_ssize >= end) break; } } map->hint = entry; if (map == &kernel_map) { vm_offset_t ksize; if ((ksize = round_page(start + length)) > kernel_vm_end) { pmap_growkernel(ksize); goto retry; } } *addr = start; return (0); } /* * vm_map_find finds an unallocated region in the target address * map with the given length. The search is defined to be * first-fit from the specified address; the region found is * returned in the same parameter. * * If object is non-NULL, ref count must be bumped by caller * prior to making call to account for the new entry. */ int vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t *addr, vm_size_t length, boolean_t fitit, vm_maptype_t maptype, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t start; int result; int count; start = *addr; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); if (fitit) { if (vm_map_findspace(map, start, length, 1, 0, addr)) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_NO_SPACE); } start = *addr; } result = vm_map_insert(map, &count, object, offset, start, start + length, maptype, prot, max, cow); vm_map_unlock(map); vm_map_entry_release(count); return (result); } /* * vm_map_simplify_entry: * * Simplify the given map entry by merging with either neighbor. This * routine also has the ability to merge with both neighbors. * * The map must be locked. * * This routine guarentees that the passed entry remains valid (though * possibly extended). When merging, this routine may delete one or * both neighbors. No action is taken on entries which have their * in-transition flag set. */ void vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry, int *countp) { vm_map_entry_t next, prev; vm_size_t prevsize, esize; if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { ++mycpu->gd_cnt.v_intrans_coll; return; } if (entry->maptype == VM_MAPTYPE_SUBMAP) return; prev = entry->prev; if (prev != &map->header) { prevsize = prev->end - prev->start; if ( (prev->end == entry->start) && (prev->maptype == entry->maptype) && (prev->object.vm_object == entry->object.vm_object) && (!prev->object.vm_object || (prev->offset + prevsize == entry->offset)) && (prev->eflags == entry->eflags) && (prev->protection == entry->protection) && (prev->max_protection == entry->max_protection) && (prev->inheritance == entry->inheritance) && (prev->wired_count == entry->wired_count)) { if (map->first_free == prev) map->first_free = entry; if (map->hint == prev) map->hint = entry; vm_map_entry_unlink(map, prev); entry->start = prev->start; entry->offset = prev->offset; if (prev->object.vm_object) vm_object_deallocate(prev->object.vm_object); vm_map_entry_dispose(map, prev, countp); } } next = entry->next; if (next != &map->header) { esize = entry->end - entry->start; if ((entry->end == next->start) && (next->maptype == entry->maptype) && (next->object.vm_object == entry->object.vm_object) && (!entry->object.vm_object || (entry->offset + esize == next->offset)) && (next->eflags == entry->eflags) && (next->protection == entry->protection) && (next->max_protection == entry->max_protection) && (next->inheritance == entry->inheritance) && (next->wired_count == entry->wired_count)) { if (map->first_free == next) map->first_free = entry; if (map->hint == next) map->hint = entry; vm_map_entry_unlink(map, next); entry->end = next->end; if (next->object.vm_object) vm_object_deallocate(next->object.vm_object); vm_map_entry_dispose(map, next, countp); } } } /* * vm_map_clip_start: [ internal use only ] * * Asserts that the given entry begins at or after * the specified address; if necessary, * it splits the entry into two. */ #define vm_map_clip_start(map, entry, startaddr, countp) \ { \ if (startaddr > entry->start) \ _vm_map_clip_start(map, entry, startaddr, countp); \ } /* * This routine is called only when it is known that * the entry must be split. */ static void _vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t start, int *countp) { vm_map_entry_t new_entry; /* * Split off the front portion -- note that we must insert the new * entry BEFORE this one, so that this entry has the specified * starting address. */ vm_map_simplify_entry(map, entry, countp); /* * If there is no object backing this entry, we might as well create * one now. If we defer it, an object can get created after the map * is clipped, and individual objects will be created for the split-up * map. This is a bit of a hack, but is also about the best place to * put this improvement. */ if (entry->object.vm_object == NULL && !map->system_map) { vm_map_entry_allocate_object(entry); } new_entry = vm_map_entry_create(map, countp); *new_entry = *entry; new_entry->end = start; entry->offset += (start - entry->start); entry->start = start; vm_map_entry_link(map, entry->prev, new_entry); switch(entry->maptype) { case VM_MAPTYPE_NORMAL: case VM_MAPTYPE_VPAGETABLE: vm_object_reference(new_entry->object.vm_object); break; default: break; } } /* * vm_map_clip_end: [ internal use only ] * * Asserts that the given entry ends at or before * the specified address; if necessary, * it splits the entry into two. */ #define vm_map_clip_end(map, entry, endaddr, countp) \ { \ if (endaddr < entry->end) \ _vm_map_clip_end(map, entry, endaddr, countp); \ } /* * This routine is called only when it is known that * the entry must be split. */ static void _vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t end, int *countp) { vm_map_entry_t new_entry; /* * If there is no object backing this entry, we might as well create * one now. If we defer it, an object can get created after the map * is clipped, and individual objects will be created for the split-up * map. This is a bit of a hack, but is also about the best place to * put this improvement. */ if (entry->object.vm_object == NULL && !map->system_map) { vm_map_entry_allocate_object(entry); } /* * Create a new entry and insert it AFTER the specified entry */ new_entry = vm_map_entry_create(map, countp); *new_entry = *entry; new_entry->start = entry->end = end; new_entry->offset += (end - entry->start); vm_map_entry_link(map, entry, new_entry); switch(entry->maptype) { case VM_MAPTYPE_NORMAL: case VM_MAPTYPE_VPAGETABLE: vm_object_reference(new_entry->object.vm_object); break; default: break; } } /* * VM_MAP_RANGE_CHECK: [ internal use only ] * * Asserts that the starting and ending region * addresses fall within the valid range of the map. */ #define VM_MAP_RANGE_CHECK(map, start, end) \ { \ if (start < vm_map_min(map)) \ start = vm_map_min(map); \ if (end > vm_map_max(map)) \ end = vm_map_max(map); \ if (start > end) \ start = end; \ } /* * vm_map_transition_wait: [ kernel use only ] * * Used to block when an in-transition collison occurs. The map * is unlocked for the sleep and relocked before the return. */ static void vm_map_transition_wait(vm_map_t map) { vm_map_unlock(map); tsleep(map, 0, "vment", 0); vm_map_lock(map); } /* * CLIP_CHECK_BACK * CLIP_CHECK_FWD * * When we do blocking operations with the map lock held it is * possible that a clip might have occured on our in-transit entry, * requiring an adjustment to the entry in our loop. These macros * help the pageable and clip_range code deal with the case. The * conditional costs virtually nothing if no clipping has occured. */ #define CLIP_CHECK_BACK(entry, save_start) \ do { \ while (entry->start != save_start) { \ entry = entry->prev; \ KASSERT(entry != &map->header, ("bad entry clip")); \ } \ } while(0) #define CLIP_CHECK_FWD(entry, save_end) \ do { \ while (entry->end != save_end) { \ entry = entry->next; \ KASSERT(entry != &map->header, ("bad entry clip")); \ } \ } while(0) /* * vm_map_clip_range: [ kernel use only ] * * Clip the specified range and return the base entry. The * range may cover several entries starting at the returned base * and the first and last entry in the covering sequence will be * properly clipped to the requested start and end address. * * If no holes are allowed you should pass the MAP_CLIP_NO_HOLES * flag. * * The MAP_ENTRY_IN_TRANSITION flag will be set for the entries * covered by the requested range. * * The map must be exclusively locked on entry and will remain locked * on return. If no range exists or the range contains holes and you * specified that no holes were allowed, NULL will be returned. This * routine may temporarily unlock the map in order avoid a deadlock when * sleeping. */ static vm_map_entry_t vm_map_clip_range(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp, int flags) { vm_map_entry_t start_entry; vm_map_entry_t entry; /* * Locate the entry and effect initial clipping. The in-transition * case does not occur very often so do not try to optimize it. */ again: if (vm_map_lookup_entry(map, start, &start_entry) == FALSE) return (NULL); entry = start_entry; if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; ++mycpu->gd_cnt.v_intrans_coll; ++mycpu->gd_cnt.v_intrans_wait; vm_map_transition_wait(map); /* * entry and/or start_entry may have been clipped while * we slept, or may have gone away entirely. We have * to restart from the lookup. */ goto again; } /* * Since we hold an exclusive map lock we do not have to restart * after clipping, even though clipping may block in zalloc. */ vm_map_clip_start(map, entry, start, countp); vm_map_clip_end(map, entry, end, countp); entry->eflags |= MAP_ENTRY_IN_TRANSITION; /* * Scan entries covered by the range. When working on the next * entry a restart need only re-loop on the current entry which * we have already locked, since 'next' may have changed. Also, * even though entry is safe, it may have been clipped so we * have to iterate forwards through the clip after sleeping. */ while (entry->next != &map->header && entry->next->start < end) { vm_map_entry_t next = entry->next; if (flags & MAP_CLIP_NO_HOLES) { if (next->start > entry->end) { vm_map_unclip_range(map, start_entry, start, entry->end, countp, flags); return(NULL); } } if (next->eflags & MAP_ENTRY_IN_TRANSITION) { vm_offset_t save_end = entry->end; next->eflags |= MAP_ENTRY_NEEDS_WAKEUP; ++mycpu->gd_cnt.v_intrans_coll; ++mycpu->gd_cnt.v_intrans_wait; vm_map_transition_wait(map); /* * clips might have occured while we blocked. */ CLIP_CHECK_FWD(entry, save_end); CLIP_CHECK_BACK(start_entry, start); continue; } /* * No restart necessary even though clip_end may block, we * are holding the map lock. */ vm_map_clip_end(map, next, end, countp); next->eflags |= MAP_ENTRY_IN_TRANSITION; entry = next; } if (flags & MAP_CLIP_NO_HOLES) { if (entry->end != end) { vm_map_unclip_range(map, start_entry, start, entry->end, countp, flags); return(NULL); } } return(start_entry); } /* * vm_map_unclip_range: [ kernel use only ] * * Undo the effect of vm_map_clip_range(). You should pass the same * flags and the same range that you passed to vm_map_clip_range(). * This code will clear the in-transition flag on the entries and * wake up anyone waiting. This code will also simplify the sequence * and attempt to merge it with entries before and after the sequence. * * The map must be locked on entry and will remain locked on return. * * Note that you should also pass the start_entry returned by * vm_map_clip_range(). However, if you block between the two calls * with the map unlocked please be aware that the start_entry may * have been clipped and you may need to scan it backwards to find * the entry corresponding with the original start address. You are * responsible for this, vm_map_unclip_range() expects the correct * start_entry to be passed to it and will KASSERT otherwise. */ static void vm_map_unclip_range( vm_map_t map, vm_map_entry_t start_entry, vm_offset_t start, vm_offset_t end, int *countp, int flags) { vm_map_entry_t entry; entry = start_entry; KASSERT(entry->start == start, ("unclip_range: illegal base entry")); while (entry != &map->header && entry->start < end) { KASSERT(entry->eflags & MAP_ENTRY_IN_TRANSITION, ("in-transition flag not set during unclip on: %p", entry)); KASSERT(entry->end <= end, ("unclip_range: tail wasn't clipped")); entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; wakeup(map); } entry = entry->next; } /* * Simplification does not block so there is no restart case. */ entry = start_entry; while (entry != &map->header && entry->start < end) { vm_map_simplify_entry(map, entry, countp); entry = entry->next; } } /* * vm_map_submap: [ kernel use only ] * * Mark the given range as handled by a subordinate map. * * This range must have been created with vm_map_find, * and no other operations may have been performed on this * range prior to calling vm_map_submap. * * Only a limited number of operations can be performed * within this rage after calling vm_map_submap: * vm_fault * [Don't try vm_map_copy!] * * To remove a submapping, one must first remove the * range from the superior map, and then destroy the * submap (if desired). [Better yet, don't try it.] */ int vm_map_submap(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_map_t submap) { vm_map_entry_t entry; int result = KERN_INVALID_ARGUMENT; int count; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &entry)) { vm_map_clip_start(map, entry, start, &count); } else { entry = entry->next; } vm_map_clip_end(map, entry, end, &count); if ((entry->start == start) && (entry->end == end) && ((entry->eflags & MAP_ENTRY_COW) == 0) && (entry->object.vm_object == NULL)) { entry->object.sub_map = submap; entry->maptype = VM_MAPTYPE_SUBMAP; result = KERN_SUCCESS; } vm_map_unlock(map); vm_map_entry_release(count); return (result); } /* * vm_map_protect: * * Sets the protection of the specified address region in the target map. * If "set_max" is specified, the maximum protection is to be set; * otherwise, only the current protection is affected. * * The protection is not applicable to submaps, but is applicable to normal * maps and maps governed by virtual page tables. For example, when operating * on a virtual page table our protection basically controls how COW occurs * on the backing object, whereas the virtual page table abstraction itself * is an abstraction for userland. */ int vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_prot_t new_prot, boolean_t set_max) { vm_map_entry_t current; vm_map_entry_t entry; int count; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &entry)) { vm_map_clip_start(map, entry, start, &count); } else { entry = entry->next; } /* * Make a first pass to check for protection violations. */ current = entry; while ((current != &map->header) && (current->start < end)) { if (current->maptype == VM_MAPTYPE_SUBMAP) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_INVALID_ARGUMENT); } if ((new_prot & current->max_protection) != new_prot) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_PROTECTION_FAILURE); } current = current->next; } /* * Go back and fix up protections. [Note that clipping is not * necessary the second time.] */ current = entry; while ((current != &map->header) && (current->start < end)) { vm_prot_t old_prot; vm_map_clip_end(map, current, end, &count); old_prot = current->protection; if (set_max) { current->protection = (current->max_protection = new_prot) & old_prot; } else { current->protection = new_prot; } /* * Update physical map if necessary. Worry about copy-on-write * here -- CHECK THIS XXX */ if (current->protection != old_prot) { #define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \ VM_PROT_ALL) pmap_protect(map->pmap, current->start, current->end, current->protection & MASK(current)); #undef MASK } vm_map_simplify_entry(map, current, &count); current = current->next; } vm_map_unlock(map); vm_map_entry_release(count); return (KERN_SUCCESS); } /* * vm_map_madvise: * * This routine traverses a processes map handling the madvise * system call. Advisories are classified as either those effecting * the vm_map_entry structure, or those effecting the underlying * objects. * * The argument is used for extended madvise calls. */ int vm_map_madvise(vm_map_t map, vm_offset_t start, vm_offset_t end, int behav, off_t value) { vm_map_entry_t current, entry; int modify_map = 0; int error = 0; int count; /* * Some madvise calls directly modify the vm_map_entry, in which case * we need to use an exclusive lock on the map and we need to perform * various clipping operations. Otherwise we only need a read-lock * on the map. */ count = vm_map_entry_reserve(MAP_RESERVE_COUNT); switch(behav) { case MADV_NORMAL: case MADV_SEQUENTIAL: case MADV_RANDOM: case MADV_NOSYNC: case MADV_AUTOSYNC: case MADV_NOCORE: case MADV_CORE: case MADV_SETMAP: case MADV_INVAL: modify_map = 1; vm_map_lock(map); break; case MADV_WILLNEED: case MADV_DONTNEED: case MADV_FREE: vm_map_lock_read(map); break; default: vm_map_entry_release(count); return (EINVAL); } /* * Locate starting entry and clip if necessary. */ VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &entry)) { if (modify_map) vm_map_clip_start(map, entry, start, &count); } else { entry = entry->next; } if (modify_map) { /* * madvise behaviors that are implemented in the vm_map_entry. * * We clip the vm_map_entry so that behavioral changes are * limited to the specified address range. */ for (current = entry; (current != &map->header) && (current->start < end); current = current->next ) { if (current->maptype == VM_MAPTYPE_SUBMAP) continue; vm_map_clip_end(map, current, end, &count); switch (behav) { case MADV_NORMAL: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_NORMAL); break; case MADV_SEQUENTIAL: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_SEQUENTIAL); break; case MADV_RANDOM: vm_map_entry_set_behavior(current, MAP_ENTRY_BEHAV_RANDOM); break; case MADV_NOSYNC: current->eflags |= MAP_ENTRY_NOSYNC; break; case MADV_AUTOSYNC: current->eflags &= ~MAP_ENTRY_NOSYNC; break; case MADV_NOCORE: current->eflags |= MAP_ENTRY_NOCOREDUMP; break; case MADV_CORE: current->eflags &= ~MAP_ENTRY_NOCOREDUMP; break; case MADV_INVAL: /* * Invalidate the related pmap entries, used * to flush portions of the real kernel's * pmap when the caller has removed or * modified existing mappings in a virtual * page table. */ pmap_remove(map->pmap, current->start, current->end); break; case MADV_SETMAP: /* * Set the page directory page for a map * governed by a virtual page table. Mark * the entry as being governed by a virtual * page table if it is not. * * XXX the page directory page is stored * in the avail_ssize field if the map_entry. * * XXX the map simplification code does not * compare this field so weird things may * happen if you do not apply this function * to the entire mapping governed by the * virtual page table. */ if (current->maptype != VM_MAPTYPE_VPAGETABLE) { error = EINVAL; break; } current->aux.master_pde = value; pmap_remove(map->pmap, current->start, current->end); break; default: error = EINVAL; break; } vm_map_simplify_entry(map, current, &count); } vm_map_unlock(map); } else { vm_pindex_t pindex; int count; /* * madvise behaviors that are implemented in the underlying * vm_object. * * Since we don't clip the vm_map_entry, we have to clip * the vm_object pindex and count. * * NOTE! We currently do not support these functions on * virtual page tables. */ for (current = entry; (current != &map->header) && (current->start < end); current = current->next ) { vm_offset_t useStart; if (current->maptype != VM_MAPTYPE_NORMAL) continue; pindex = OFF_TO_IDX(current->offset); count = atop(current->end - current->start); useStart = current->start; if (current->start < start) { pindex += atop(start - current->start); count -= atop(start - current->start); useStart = start; } if (current->end > end) count -= atop(current->end - end); if (count <= 0) continue; vm_object_madvise(current->object.vm_object, pindex, count, behav); /* * Try to populate the page table. Mappings governed * by virtual page tables cannot be pre-populated * without a lot of work so don't try. */ if (behav == MADV_WILLNEED && current->maptype != VM_MAPTYPE_VPAGETABLE) { pmap_object_init_pt( map->pmap, useStart, current->protection, current->object.vm_object, pindex, (count << PAGE_SHIFT), MAP_PREFAULT_MADVISE ); } } vm_map_unlock_read(map); } vm_map_entry_release(count); return(error); } /* * vm_map_inherit: * * Sets the inheritance of the specified address * range in the target map. Inheritance * affects how the map will be shared with * child maps at the time of vm_map_fork. */ int vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_inherit_t new_inheritance) { vm_map_entry_t entry; vm_map_entry_t temp_entry; int count; switch (new_inheritance) { case VM_INHERIT_NONE: case VM_INHERIT_COPY: case VM_INHERIT_SHARE: break; default: return (KERN_INVALID_ARGUMENT); } count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (vm_map_lookup_entry(map, start, &temp_entry)) { entry = temp_entry; vm_map_clip_start(map, entry, start, &count); } else entry = temp_entry->next; while ((entry != &map->header) && (entry->start < end)) { vm_map_clip_end(map, entry, end, &count); entry->inheritance = new_inheritance; vm_map_simplify_entry(map, entry, &count); entry = entry->next; } vm_map_unlock(map); vm_map_entry_release(count); return (KERN_SUCCESS); } /* * Implement the semantics of mlock */ int vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, boolean_t new_pageable) { vm_map_entry_t entry; vm_map_entry_t start_entry; vm_offset_t end; int rv = KERN_SUCCESS; int count; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, real_end); end = real_end; start_entry = vm_map_clip_range(map, start, end, &count, MAP_CLIP_NO_HOLES); if (start_entry == NULL) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_INVALID_ADDRESS); } if (new_pageable == 0) { entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { vm_offset_t save_start; vm_offset_t save_end; /* * Already user wired or hard wired (trivial cases) */ if (entry->eflags & MAP_ENTRY_USER_WIRED) { entry = entry->next; continue; } if (entry->wired_count != 0) { entry->wired_count++; entry->eflags |= MAP_ENTRY_USER_WIRED; entry = entry->next; continue; } /* * A new wiring requires instantiation of appropriate * management structures and the faulting in of the * page. */ if (entry->maptype != VM_MAPTYPE_SUBMAP) { int copyflag = entry->eflags & MAP_ENTRY_NEEDS_COPY; if (copyflag && ((entry->protection & VM_PROT_WRITE) != 0)) { vm_map_entry_shadow(entry); } else if (entry->object.vm_object == NULL && !map->system_map) { vm_map_entry_allocate_object(entry); } } entry->wired_count++; entry->eflags |= MAP_ENTRY_USER_WIRED; /* * Now fault in the area. Note that vm_fault_wire() * may release the map lock temporarily, it will be * relocked on return. The in-transition * flag protects the entries. */ save_start = entry->start; save_end = entry->end; rv = vm_fault_wire(map, entry, TRUE); if (rv) { CLIP_CHECK_BACK(entry, save_start); for (;;) { KASSERT(entry->wired_count == 1, ("bad wired_count on entry")); entry->eflags &= ~MAP_ENTRY_USER_WIRED; entry->wired_count = 0; if (entry->end == save_end) break; entry = entry->next; KASSERT(entry != &map->header, ("bad entry clip during backout")); } end = save_start; /* unwire the rest */ break; } /* * note that even though the entry might have been * clipped, the USER_WIRED flag we set prevents * duplication so we do not have to do a * clip check. */ entry = entry->next; } /* * If we failed fall through to the unwiring section to * unwire what we had wired so far. 'end' has already * been adjusted. */ if (rv) new_pageable = 1; /* * start_entry might have been clipped if we unlocked the * map and blocked. No matter how clipped it has gotten * there should be a fragment that is on our start boundary. */ CLIP_CHECK_BACK(start_entry, start); } /* * Deal with the unwiring case. */ if (new_pageable) { /* * This is the unwiring case. We must first ensure that the * range to be unwired is really wired down. We know there * are no holes. */ entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { if ((entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { rv = KERN_INVALID_ARGUMENT; goto done; } KASSERT(entry->wired_count != 0, ("wired count was 0 with USER_WIRED set! %p", entry)); entry = entry->next; } /* * Now decrement the wiring count for each region. If a region * becomes completely unwired, unwire its physical pages and * mappings. */ /* * The map entries are processed in a loop, checking to * make sure the entry is wired and asserting it has a wired * count. However, another loop was inserted more-or-less in * the middle of the unwiring path. This loop picks up the * "entry" loop variable from the first loop without first * setting it to start_entry. Naturally, the secound loop * is never entered and the pages backing the entries are * never unwired. This can lead to a leak of wired pages. */ entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { KASSERT(entry->eflags & MAP_ENTRY_USER_WIRED, ("expected USER_WIRED on entry %p", entry)); entry->eflags &= ~MAP_ENTRY_USER_WIRED; entry->wired_count--; if (entry->wired_count == 0) vm_fault_unwire(map, entry); entry = entry->next; } } done: vm_map_unclip_range(map, start_entry, start, real_end, &count, MAP_CLIP_NO_HOLES); map->timestamp++; vm_map_unlock(map); vm_map_entry_release(count); return (rv); } /* * vm_map_wire: * * Sets the pageability of the specified address * range in the target map. Regions specified * as not pageable require locked-down physical * memory and physical page maps. * * The map must not be locked, but a reference * must remain to the map throughout the call. * * This function may be called via the zalloc path and must properly * reserve map entries for kernel_map. */ int vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t real_end, int kmflags) { vm_map_entry_t entry; vm_map_entry_t start_entry; vm_offset_t end; int rv = KERN_SUCCESS; int count; if (kmflags & KM_KRESERVE) count = vm_map_entry_kreserve(MAP_RESERVE_COUNT); else count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, real_end); end = real_end; start_entry = vm_map_clip_range(map, start, end, &count, MAP_CLIP_NO_HOLES); if (start_entry == NULL) { vm_map_unlock(map); rv = KERN_INVALID_ADDRESS; goto failure; } if ((kmflags & KM_PAGEABLE) == 0) { /* * Wiring. * * 1. Holding the write lock, we create any shadow or zero-fill * objects that need to be created. Then we clip each map * entry to the region to be wired and increment its wiring * count. We create objects before clipping the map entries * to avoid object proliferation. * * 2. We downgrade to a read lock, and call vm_fault_wire to * fault in the pages for any newly wired area (wired_count is * 1). * * Downgrading to a read lock for vm_fault_wire avoids a * possible deadlock with another process that may have faulted * on one of the pages to be wired (it would mark the page busy, * blocking us, then in turn block on the map lock that we * hold). Because of problems in the recursive lock package, * we cannot upgrade to a write lock in vm_map_lookup. Thus, * any actions that require the write lock must be done * beforehand. Because we keep the read lock on the map, the * copy-on-write status of the entries we modify here cannot * change. */ entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { /* * Trivial case if the entry is already wired */ if (entry->wired_count) { entry->wired_count++; entry = entry->next; continue; } /* * The entry is being newly wired, we have to setup * appropriate management structures. A shadow * object is required for a copy-on-write region, * or a normal object for a zero-fill region. We * do not have to do this for entries that point to sub * maps because we won't hold the lock on the sub map. */ if (entry->maptype != VM_MAPTYPE_SUBMAP) { int copyflag = entry->eflags & MAP_ENTRY_NEEDS_COPY; if (copyflag && ((entry->protection & VM_PROT_WRITE) != 0)) { vm_map_entry_shadow(entry); } else if (entry->object.vm_object == NULL && !map->system_map) { vm_map_entry_allocate_object(entry); } } entry->wired_count++; entry = entry->next; } /* * Pass 2. */ /* * HACK HACK HACK HACK * * Unlock the map to avoid deadlocks. The in-transit flag * protects us from most changes but note that * clipping may still occur. To prevent clipping from * occuring after the unlock, except for when we are * blocking in vm_fault_wire, we must run in a critical * section, otherwise our accesses to entry->start and * entry->end could be corrupted. We have to enter the * critical section prior to unlocking so start_entry does * not change out from under us at the very beginning of the * loop. * * HACK HACK HACK HACK */ crit_enter(); entry = start_entry; while (entry != &map->header && entry->start < end) { /* * If vm_fault_wire fails for any page we need to undo * what has been done. We decrement the wiring count * for those pages which have not yet been wired (now) * and unwire those that have (later). */ vm_offset_t save_start = entry->start; vm_offset_t save_end = entry->end; if (entry->wired_count == 1) rv = vm_fault_wire(map, entry, FALSE); if (rv) { CLIP_CHECK_BACK(entry, save_start); for (;;) { KASSERT(entry->wired_count == 1, ("wired_count changed unexpectedly")); entry->wired_count = 0; if (entry->end == save_end) break; entry = entry->next; KASSERT(entry != &map->header, ("bad entry clip during backout")); } end = save_start; break; } CLIP_CHECK_FWD(entry, save_end); entry = entry->next; } crit_exit(); /* * If a failure occured undo everything by falling through * to the unwiring code. 'end' has already been adjusted * appropriately. */ if (rv) kmflags |= KM_PAGEABLE; /* * start_entry is still IN_TRANSITION but may have been * clipped since vm_fault_wire() unlocks and relocks the * map. No matter how clipped it has gotten there should * be a fragment that is on our start boundary. */ CLIP_CHECK_BACK(start_entry, start); } if (kmflags & KM_PAGEABLE) { /* * This is the unwiring case. We must first ensure that the * range to be unwired is really wired down. We know there * are no holes. */ entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { if (entry->wired_count == 0) { rv = KERN_INVALID_ARGUMENT; goto done; } entry = entry->next; } /* * Now decrement the wiring count for each region. If a region * becomes completely unwired, unwire its physical pages and * mappings. */ entry = start_entry; while ((entry != &map->header) && (entry->start < end)) { entry->wired_count--; if (entry->wired_count == 0) vm_fault_unwire(map, entry); entry = entry->next; } } done: vm_map_unclip_range(map, start_entry, start, real_end, &count, MAP_CLIP_NO_HOLES); map->timestamp++; vm_map_unlock(map); failure: if (kmflags & KM_KRESERVE) vm_map_entry_krelease(count); else vm_map_entry_release(count); return (rv); } /* * vm_map_set_wired_quick() * * Mark a newly allocated address range as wired but do not fault in * the pages. The caller is expected to load the pages into the object. * * The map must be locked on entry and will remain locked on return. */ void vm_map_set_wired_quick(vm_map_t map, vm_offset_t addr, vm_size_t size, int *countp) { vm_map_entry_t scan; vm_map_entry_t entry; entry = vm_map_clip_range(map, addr, addr + size, countp, MAP_CLIP_NO_HOLES); for (scan = entry; scan != &map->header && scan->start < addr + size; scan = scan->next) { KKASSERT(entry->wired_count == 0); entry->wired_count = 1; } vm_map_unclip_range(map, entry, addr, addr + size, countp, MAP_CLIP_NO_HOLES); } /* * vm_map_clean * * Push any dirty cached pages in the address range to their pager. * If syncio is TRUE, dirty pages are written synchronously. * If invalidate is TRUE, any cached pages are freed as well. * * Returns an error if any part of the specified range is not mapped. */ int vm_map_clean(vm_map_t map, vm_offset_t start, vm_offset_t end, boolean_t syncio, boolean_t invalidate) { vm_map_entry_t current; vm_map_entry_t entry; vm_size_t size; vm_object_t object; vm_ooffset_t offset; vm_map_lock_read(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &entry)) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } /* * Make a first pass to check for holes. */ for (current = entry; current->start < end; current = current->next) { if (current->maptype == VM_MAPTYPE_SUBMAP) { vm_map_unlock_read(map); return (KERN_INVALID_ARGUMENT); } if (end > current->end && (current->next == &map->header || current->end != current->next->start)) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } } if (invalidate) pmap_remove(vm_map_pmap(map), start, end); /* * Make a second pass, cleaning/uncaching pages from the indicated * objects as we go. */ for (current = entry; current->start < end; current = current->next) { offset = current->offset + (start - current->start); size = (end <= current->end ? end : current->end) - start; if (current->maptype == VM_MAPTYPE_SUBMAP) { vm_map_t smap; vm_map_entry_t tentry; vm_size_t tsize; smap = current->object.sub_map; vm_map_lock_read(smap); vm_map_lookup_entry(smap, offset, &tentry); tsize = tentry->end - offset; if (tsize < size) size = tsize; object = tentry->object.vm_object; offset = tentry->offset + (offset - tentry->start); vm_map_unlock_read(smap); } else { object = current->object.vm_object; } /* * Note that there is absolutely no sense in writing out * anonymous objects, so we track down the vnode object * to write out. * We invalidate (remove) all pages from the address space * anyway, for semantic correctness. * * note: certain anonymous maps, such as MAP_NOSYNC maps, * may start out with a NULL object. */ while (object && object->backing_object) { offset += object->backing_object_offset; object = object->backing_object; if (object->size < OFF_TO_IDX( offset + size)) size = IDX_TO_OFF(object->size) - offset; } if (object && (object->type == OBJT_VNODE) && (current->protection & VM_PROT_WRITE)) { /* * Flush pages if writing is allowed, invalidate them * if invalidation requested. Pages undergoing I/O * will be ignored by vm_object_page_remove(). * * We cannot lock the vnode and then wait for paging * to complete without deadlocking against vm_fault. * Instead we simply call vm_object_page_remove() and * allow it to block internally on a page-by-page * basis when it encounters pages undergoing async * I/O. */ int flags; vm_object_reference(object); vn_lock(object->handle, LK_EXCLUSIVE | LK_RETRY); flags = (syncio || invalidate) ? OBJPC_SYNC : 0; flags |= invalidate ? OBJPC_INVAL : 0; /* * When operating on a virtual page table just * flush the whole object. XXX we probably ought * to */ switch(current->maptype) { case VM_MAPTYPE_NORMAL: vm_object_page_clean(object, OFF_TO_IDX(offset), OFF_TO_IDX(offset + size + PAGE_MASK), flags); break; case VM_MAPTYPE_VPAGETABLE: vm_object_page_clean(object, 0, 0, flags); break; } vn_unlock(((struct vnode *)object->handle)); vm_object_deallocate(object); } if (object && invalidate && ((object->type == OBJT_VNODE) || (object->type == OBJT_DEVICE))) { int clean_only = (object->type == OBJT_DEVICE) ? FALSE : TRUE; vm_object_reference(object); switch(current->maptype) { case VM_MAPTYPE_NORMAL: vm_object_page_remove(object, OFF_TO_IDX(offset), OFF_TO_IDX(offset + size + PAGE_MASK), clean_only); break; case VM_MAPTYPE_VPAGETABLE: vm_object_page_remove(object, 0, 0, clean_only); break; } vm_object_deallocate(object); } start += size; } vm_map_unlock_read(map); return (KERN_SUCCESS); } /* * vm_map_entry_unwire: [ internal use only ] * * Make the region specified by this entry pageable. * * The map in question should be locked. * [This is the reason for this routine's existence.] */ static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry) { entry->eflags &= ~MAP_ENTRY_USER_WIRED; entry->wired_count = 0; vm_fault_unwire(map, entry); } /* * vm_map_entry_delete: [ internal use only ] * * Deallocate the given entry from the target map. */ static void vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry, int *countp) { vm_map_entry_unlink(map, entry); map->size -= entry->end - entry->start; switch(entry->maptype) { case VM_MAPTYPE_NORMAL: case VM_MAPTYPE_VPAGETABLE: vm_object_deallocate(entry->object.vm_object); break; default: break; } vm_map_entry_dispose(map, entry, countp); } /* * vm_map_delete: [ internal use only ] * * Deallocates the given address range from the target * map. */ int vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end, int *countp) { vm_object_t object; vm_map_entry_t entry; vm_map_entry_t first_entry; again: /* * Find the start of the region, and clip it. Set entry to point * at the first record containing the requested address or, if no * such record exists, the next record with a greater address. The * loop will run from this point until a record beyond the termination * address is encountered. * * map->hint must be adjusted to not point to anything we delete, * so set it to the entry prior to the one being deleted. * * GGG see other GGG comment. */ if (vm_map_lookup_entry(map, start, &first_entry)) { entry = first_entry; vm_map_clip_start(map, entry, start, countp); map->hint = entry->prev; /* possible problem XXX */ } else { map->hint = first_entry; /* possible problem XXX */ entry = first_entry->next; } /* * If a hole opens up prior to the current first_free then * adjust first_free. As with map->hint, map->first_free * cannot be left set to anything we might delete. */ if (entry == &map->header) { map->first_free = &map->header; } else if (map->first_free->start >= start) { map->first_free = entry->prev; } /* * Step through all entries in this region */ while ((entry != &map->header) && (entry->start < end)) { vm_map_entry_t next; vm_offset_t s, e; vm_pindex_t offidxstart, offidxend, count; /* * If we hit an in-transition entry we have to sleep and * retry. It's easier (and not really slower) to just retry * since this case occurs so rarely and the hint is already * pointing at the right place. We have to reset the * start offset so as not to accidently delete an entry * another process just created in vacated space. */ if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; start = entry->start; ++mycpu->gd_cnt.v_intrans_coll; ++mycpu->gd_cnt.v_intrans_wait; vm_map_transition_wait(map); goto again; } vm_map_clip_end(map, entry, end, countp); s = entry->start; e = entry->end; next = entry->next; offidxstart = OFF_TO_IDX(entry->offset); count = OFF_TO_IDX(e - s); object = entry->object.vm_object; /* * Unwire before removing addresses from the pmap; otherwise, * unwiring will put the entries back in the pmap. */ if (entry->wired_count != 0) vm_map_entry_unwire(map, entry); offidxend = offidxstart + count; if (object == &kernel_object) { vm_object_page_remove(object, offidxstart, offidxend, FALSE); } else { pmap_remove(map->pmap, s, e); if (object != NULL && object->ref_count != 1 && (object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING && (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { vm_object_collapse(object); vm_object_page_remove(object, offidxstart, offidxend, FALSE); if (object->type == OBJT_SWAP) { swap_pager_freespace(object, offidxstart, count); } if (offidxend >= object->size && offidxstart < object->size) { object->size = offidxstart; } } } /* * Delete the entry (which may delete the object) only after * removing all pmap entries pointing to its pages. * (Otherwise, its page frames may be reallocated, and any * modify bits will be set in the wrong object!) */ vm_map_entry_delete(map, entry, countp); entry = next; } return (KERN_SUCCESS); } /* * vm_map_remove: * * Remove the given address range from the target map. * This is the exported form of vm_map_delete. */ int vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end) { int result; int count; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); result = vm_map_delete(map, start, end, &count); vm_map_unlock(map); vm_map_entry_release(count); return (result); } /* * vm_map_check_protection: * * Assert that the target map allows the specified * privilege on the entire address region given. * The entire region must be allocated. */ boolean_t vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end, vm_prot_t protection) { vm_map_entry_t entry; vm_map_entry_t tmp_entry; if (!vm_map_lookup_entry(map, start, &tmp_entry)) { return (FALSE); } entry = tmp_entry; while (start < end) { if (entry == &map->header) { return (FALSE); } /* * No holes allowed! */ if (start < entry->start) { return (FALSE); } /* * Check protection associated with entry. */ if ((entry->protection & protection) != protection) { return (FALSE); } /* go to next entry */ start = entry->end; entry = entry->next; } return (TRUE); } /* * Split the pages in a map entry into a new object. This affords * easier removal of unused pages, and keeps object inheritance from * being a negative impact on memory usage. */ static void vm_map_split(vm_map_entry_t entry) { vm_page_t m; vm_object_t orig_object, new_object, source; vm_offset_t s, e; vm_pindex_t offidxstart, offidxend, idx; vm_size_t size; vm_ooffset_t offset; orig_object = entry->object.vm_object; if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) return; if (orig_object->ref_count <= 1) return; offset = entry->offset; s = entry->start; e = entry->end; offidxstart = OFF_TO_IDX(offset); offidxend = offidxstart + OFF_TO_IDX(e - s); size = offidxend - offidxstart; new_object = vm_pager_allocate(orig_object->type, NULL, IDX_TO_OFF(size), VM_PROT_ALL, 0); if (new_object == NULL) return; source = orig_object->backing_object; if (source != NULL) { vm_object_reference(source); /* Referenced by new_object */ LIST_INSERT_HEAD(&source->shadow_head, new_object, shadow_list); vm_object_clear_flag(source, OBJ_ONEMAPPING); new_object->backing_object_offset = orig_object->backing_object_offset + IDX_TO_OFF(offidxstart); new_object->backing_object = source; source->shadow_count++; source->generation++; } for (idx = 0; idx < size; idx++) { vm_page_t m; /* * A critical section is required to avoid a race between * the lookup and an interrupt/unbusy/free and our busy * check. */ crit_enter(); retry: m = vm_page_lookup(orig_object, offidxstart + idx); if (m == NULL) { crit_exit(); continue; } /* * We must wait for pending I/O to complete before we can * rename the page. * * We do not have to VM_PROT_NONE the page as mappings should * not be changed by this operation. */ if (vm_page_sleep_busy(m, TRUE, "spltwt")) goto retry; vm_page_busy(m); vm_page_rename(m, new_object, idx); /* page automatically made dirty by rename and cache handled */ vm_page_busy(m); crit_exit(); } if (orig_object->type == OBJT_SWAP) { vm_object_pip_add(orig_object, 1); /* * copy orig_object pages into new_object * and destroy unneeded pages in * shadow object. */ swap_pager_copy(orig_object, new_object, offidxstart, 0); vm_object_pip_wakeup(orig_object); } /* * Wakeup the pages we played with. No spl protection is needed * for a simple wakeup. */ for (idx = 0; idx < size; idx++) { m = vm_page_lookup(new_object, idx); if (m) vm_page_wakeup(m); } entry->object.vm_object = new_object; entry->offset = 0LL; vm_object_deallocate(orig_object); } /* * vm_map_copy_entry: * * Copies the contents of the source entry to the destination * entry. The entries *must* be aligned properly. */ static void vm_map_copy_entry(vm_map_t src_map, vm_map_t dst_map, vm_map_entry_t src_entry, vm_map_entry_t dst_entry) { vm_object_t src_object; if (dst_entry->maptype == VM_MAPTYPE_SUBMAP) return; if (src_entry->maptype == VM_MAPTYPE_SUBMAP) return; if (src_entry->wired_count == 0) { /* * If the source entry is marked needs_copy, it is already * write-protected. */ if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) { pmap_protect(src_map->pmap, src_entry->start, src_entry->end, src_entry->protection & ~VM_PROT_WRITE); } /* * Make a copy of the object. */ if ((src_object = src_entry->object.vm_object) != NULL) { if ((src_object->handle == NULL) && (src_object->type == OBJT_DEFAULT || src_object->type == OBJT_SWAP)) { vm_object_collapse(src_object); if ((src_object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING) { vm_map_split(src_entry); src_object = src_entry->object.vm_object; } } vm_object_reference(src_object); vm_object_clear_flag(src_object, OBJ_ONEMAPPING); dst_entry->object.vm_object = src_object; src_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); dst_entry->eflags |= (MAP_ENTRY_COW|MAP_ENTRY_NEEDS_COPY); dst_entry->offset = src_entry->offset; } else { dst_entry->object.vm_object = NULL; dst_entry->offset = 0; } pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, dst_entry->end - dst_entry->start, src_entry->start); } else { /* * Of course, wired down pages can't be set copy-on-write. * Cause wired pages to be copied into the new map by * simulating faults (the new pages are pageable) */ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry); } } /* * vmspace_fork: * Create a new process vmspace structure and vm_map * based on those of an existing process. The new map * is based on the old map, according to the inheritance * values on the regions in that map. * * The source map must not be locked. */ struct vmspace * vmspace_fork(struct vmspace *vm1) { struct vmspace *vm2; vm_map_t old_map = &vm1->vm_map; vm_map_t new_map; vm_map_entry_t old_entry; vm_map_entry_t new_entry; vm_object_t object; int count; vm_map_lock(old_map); old_map->infork = 1; /* * XXX Note: upcalls are not copied. */ vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset); bcopy(&vm1->vm_startcopy, &vm2->vm_startcopy, (caddr_t)&vm1->vm_endcopy - (caddr_t)&vm1->vm_startcopy); new_map = &vm2->vm_map; /* XXX */ new_map->timestamp = 1; count = 0; old_entry = old_map->header.next; while (old_entry != &old_map->header) { ++count; old_entry = old_entry->next; } count = vm_map_entry_reserve(count + MAP_RESERVE_COUNT); old_entry = old_map->header.next; while (old_entry != &old_map->header) { if (old_entry->maptype == VM_MAPTYPE_SUBMAP) panic("vm_map_fork: encountered a submap"); switch (old_entry->inheritance) { case VM_INHERIT_NONE: break; case VM_INHERIT_SHARE: /* * Clone the entry, creating the shared object if * necessary. */ object = old_entry->object.vm_object; if (object == NULL) { vm_map_entry_allocate_object(old_entry); object = old_entry->object.vm_object; } /* * Add the reference before calling vm_map_entry_shadow * to insure that a shadow object is created. */ vm_object_reference(object); if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { vm_map_entry_shadow(old_entry); /* Transfer the second reference too. */ vm_object_reference( old_entry->object.vm_object); vm_object_deallocate(object); object = old_entry->object.vm_object; } vm_object_clear_flag(object, OBJ_ONEMAPPING); /* * Clone the entry, referencing the shared object. */ new_entry = vm_map_entry_create(new_map, &count); *new_entry = *old_entry; new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; new_entry->wired_count = 0; /* * Insert the entry into the new map -- we know we're * inserting at the end of the new map. */ vm_map_entry_link(new_map, new_map->header.prev, new_entry); /* * Update the physical map */ pmap_copy(new_map->pmap, old_map->pmap, new_entry->start, (old_entry->end - old_entry->start), old_entry->start); break; case VM_INHERIT_COPY: /* * Clone the entry and link into the map. */ new_entry = vm_map_entry_create(new_map, &count); *new_entry = *old_entry; new_entry->eflags &= ~MAP_ENTRY_USER_WIRED; new_entry->wired_count = 0; new_entry->object.vm_object = NULL; vm_map_entry_link(new_map, new_map->header.prev, new_entry); vm_map_copy_entry(old_map, new_map, old_entry, new_entry); break; } old_entry = old_entry->next; } new_map->size = old_map->size; old_map->infork = 0; vm_map_unlock(old_map); vm_map_entry_release(count); return (vm2); } int vm_map_stack (vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, int flags, vm_prot_t prot, vm_prot_t max, int cow) { vm_map_entry_t prev_entry; vm_map_entry_t new_stack_entry; vm_size_t init_ssize; int rv; int count; vm_offset_t tmpaddr; cow |= MAP_IS_STACK; if (max_ssize < sgrowsiz) init_ssize = max_ssize; else init_ssize = sgrowsiz; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); vm_map_lock(map); /* * Find space for the mapping */ if ((flags & (MAP_FIXED | MAP_TRYFIXED)) == 0) { if (vm_map_findspace(map, addrbos, max_ssize, 1, flags, &tmpaddr)) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_NO_SPACE); } addrbos = tmpaddr; } /* If addr is already mapped, no go */ if (vm_map_lookup_entry(map, addrbos, &prev_entry)) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_NO_SPACE); } #if 0 /* XXX already handled by kern_mmap() */ /* If we would blow our VMEM resource limit, no go */ if (map->size + init_ssize > curproc->p_rlimit[RLIMIT_VMEM].rlim_cur) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_NO_SPACE); } #endif /* * If we can't accomodate max_ssize in the current mapping, * no go. However, we need to be aware that subsequent user * mappings might map into the space we have reserved for * stack, and currently this space is not protected. * * Hopefully we will at least detect this condition * when we try to grow the stack. */ if ((prev_entry->next != &map->header) && (prev_entry->next->start < addrbos + max_ssize)) { vm_map_unlock(map); vm_map_entry_release(count); return (KERN_NO_SPACE); } /* * We initially map a stack of only init_ssize. We will * grow as needed later. Since this is to be a grow * down stack, we map at the top of the range. * * Note: we would normally expect prot and max to be * VM_PROT_ALL, and cow to be 0. Possibly we should * eliminate these as input parameters, and just * pass these values here in the insert call. */ rv = vm_map_insert(map, &count, NULL, 0, addrbos + max_ssize - init_ssize, addrbos + max_ssize, VM_MAPTYPE_NORMAL, prot, max, cow); /* Now set the avail_ssize amount */ if (rv == KERN_SUCCESS) { if (prev_entry != &map->header) vm_map_clip_end(map, prev_entry, addrbos + max_ssize - init_ssize, &count); new_stack_entry = prev_entry->next; if (new_stack_entry->end != addrbos + max_ssize || new_stack_entry->start != addrbos + max_ssize - init_ssize) panic ("Bad entry start/end for new stack entry"); else new_stack_entry->aux.avail_ssize = max_ssize - init_ssize; } vm_map_unlock(map); vm_map_entry_release(count); return (rv); } /* Attempts to grow a vm stack entry. Returns KERN_SUCCESS if the * desired address is already mapped, or if we successfully grow * the stack. Also returns KERN_SUCCESS if addr is outside the * stack range (this is strange, but preserves compatibility with * the grow function in vm_machdep.c). */ int vm_map_growstack (struct proc *p, vm_offset_t addr) { vm_map_entry_t prev_entry; vm_map_entry_t stack_entry; vm_map_entry_t new_stack_entry; struct vmspace *vm = p->p_vmspace; vm_map_t map = &vm->vm_map; vm_offset_t end; int grow_amount; int rv = KERN_SUCCESS; int is_procstack; int use_read_lock = 1; int count; count = vm_map_entry_reserve(MAP_RESERVE_COUNT); Retry: if (use_read_lock) vm_map_lock_read(map); else vm_map_lock(map); /* If addr is already in the entry range, no need to grow.*/ if (vm_map_lookup_entry(map, addr, &prev_entry)) goto done; if ((stack_entry = prev_entry->next) == &map->header) goto done; if (prev_entry == &map->header) end = stack_entry->start - stack_entry->aux.avail_ssize; else end = prev_entry->end; /* * This next test mimics the old grow function in vm_machdep.c. * It really doesn't quite make sense, but we do it anyway * for compatibility. * * If not growable stack, return success. This signals the * caller to proceed as he would normally with normal vm. */ if (stack_entry->aux.avail_ssize < 1 || addr >= stack_entry->start || addr < stack_entry->start - stack_entry->aux.avail_ssize) { goto done; } /* Find the minimum grow amount */ grow_amount = roundup (stack_entry->start - addr, PAGE_SIZE); if (grow_amount > stack_entry->aux.avail_ssize) { rv = KERN_NO_SPACE; goto done; } /* * If there is no longer enough space between the entries * nogo, and adjust the available space. Note: this * should only happen if the user has mapped into the * stack area after the stack was created, and is * probably an error. * * This also effectively destroys any guard page the user * might have intended by limiting the stack size. */ if (grow_amount > stack_entry->start - end) { if (use_read_lock && vm_map_lock_upgrade(map)) { use_read_lock = 0; goto Retry; } use_read_lock = 0; stack_entry->aux.avail_ssize = stack_entry->start - end; rv = KERN_NO_SPACE; goto done; } is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr; /* If this is the main process stack, see if we're over the * stack limit. */ if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > p->p_rlimit[RLIMIT_STACK].rlim_cur)) { rv = KERN_NO_SPACE; goto done; } /* Round up the grow amount modulo SGROWSIZ */ grow_amount = roundup (grow_amount, sgrowsiz); if (grow_amount > stack_entry->aux.avail_ssize) { grow_amount = stack_entry->aux.avail_ssize; } if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > p->p_rlimit[RLIMIT_STACK].rlim_cur)) { grow_amount = p->p_rlimit[RLIMIT_STACK].rlim_cur - ctob(vm->vm_ssize); } /* If we would blow our VMEM resource limit, no go */ if (map->size + grow_amount > p->p_rlimit[RLIMIT_VMEM].rlim_cur) { rv = KERN_NO_SPACE; goto done; } if (use_read_lock && vm_map_lock_upgrade(map)) { use_read_lock = 0; goto Retry; } use_read_lock = 0; /* Get the preliminary new entry start value */ addr = stack_entry->start - grow_amount; /* If this puts us into the previous entry, cut back our growth * to the available space. Also, see the note above. */ if (addr < end) { stack_entry->aux.avail_ssize = stack_entry->start - end; addr = end; } rv = vm_map_insert(map, &count, NULL, 0, addr, stack_entry->start, VM_MAPTYPE_NORMAL, VM_PROT_ALL, VM_PROT_ALL, 0); /* Adjust the available stack space by the amount we grew. */ if (rv == KERN_SUCCESS) { if (prev_entry != &map->header) vm_map_clip_end(map, prev_entry, addr, &count); new_stack_entry = prev_entry->next; if (new_stack_entry->end != stack_entry->start || new_stack_entry->start != addr) panic ("Bad stack grow start/end in new stack entry"); else { new_stack_entry->aux.avail_ssize = stack_entry->aux.avail_ssize - (new_stack_entry->end - new_stack_entry->start); if (is_procstack) vm->vm_ssize += btoc(new_stack_entry->end - new_stack_entry->start); } } done: if (use_read_lock) vm_map_unlock_read(map); else vm_map_unlock(map); vm_map_entry_release(count); return (rv); } /* * Unshare the specified VM space for exec. If other processes are * mapped to it, then create a new one. The new vmspace is null. */ void vmspace_exec(struct proc *p, struct vmspace *vmcopy) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; vm_map_t map = &p->p_vmspace->vm_map; /* * If we are execing a resident vmspace we fork it, otherwise * we create a new vmspace. Note that exitingcnt and upcalls * are not copied to the new vmspace. */ if (vmcopy) { newvmspace = vmspace_fork(vmcopy); } else { newvmspace = vmspace_alloc(map->min_offset, map->max_offset); bcopy(&oldvmspace->vm_startcopy, &newvmspace->vm_startcopy, (caddr_t)&oldvmspace->vm_endcopy - (caddr_t)&oldvmspace->vm_startcopy); } /* * Finish initializing the vmspace before assigning it * to the process. The vmspace will become the current vmspace * if p == curproc. */ pmap_pinit2(vmspace_pmap(newvmspace)); pmap_replacevm(p, newvmspace, 0); sysref_put(&oldvmspace->vm_sysref); } /* * Unshare the specified VM space for forcing COW. This * is called by rfork, for the (RFMEM|RFPROC) == 0 case. * * The exitingcnt test is not strictly necessary but has been * included for code sanity (to make the code a bit more deterministic). */ void vmspace_unshare(struct proc *p) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; if (oldvmspace->vm_sysref.refcnt == 1 && oldvmspace->vm_exitingcnt == 0) return; newvmspace = vmspace_fork(oldvmspace); pmap_pinit2(vmspace_pmap(newvmspace)); pmap_replacevm(p, newvmspace, 0); sysref_put(&oldvmspace->vm_sysref); } /* * vm_map_lookup: * * Finds the VM object, offset, and * protection for a given virtual address in the * specified map, assuming a page fault of the * type specified. * * Leaves the map in question locked for read; return * values are guaranteed until a vm_map_lookup_done * call is performed. Note that the map argument * is in/out; the returned map must be used in * the call to vm_map_lookup_done. * * A handle (out_entry) is returned for use in * vm_map_lookup_done, to make that fast. * * If a lookup is requested with "write protection" * specified, the map may be changed to perform virtual * copying operations, although the data referenced will * remain the same. */ int vm_map_lookup(vm_map_t *var_map, /* IN/OUT */ vm_offset_t vaddr, vm_prot_t fault_typea, vm_map_entry_t *out_entry, /* OUT */ vm_object_t *object, /* OUT */ vm_pindex_t *pindex, /* OUT */ vm_prot_t *out_prot, /* OUT */ boolean_t *wired) /* OUT */ { vm_map_entry_t entry; vm_map_t map = *var_map; vm_prot_t prot; vm_prot_t fault_type = fault_typea; int use_read_lock = 1; int rv = KERN_SUCCESS; RetryLookup: if (use_read_lock) vm_map_lock_read(map); else vm_map_lock(map); /* * If the map has an interesting hint, try it before calling full * blown lookup routine. */ entry = map->hint; *out_entry = entry; if ((entry == &map->header) || (vaddr < entry->start) || (vaddr >= entry->end)) { vm_map_entry_t tmp_entry; /* * Entry was either not a valid hint, or the vaddr was not * contained in the entry, so do a full lookup. */ if (!vm_map_lookup_entry(map, vaddr, &tmp_entry)) { rv = KERN_INVALID_ADDRESS; goto done; } entry = tmp_entry; *out_entry = entry; } /* * Handle submaps. */ if (entry->maptype == VM_MAPTYPE_SUBMAP) { vm_map_t old_map = map; *var_map = map = entry->object.sub_map; if (use_read_lock) vm_map_unlock_read(old_map); else vm_map_unlock(old_map); use_read_lock = 1; goto RetryLookup; } /* * Check whether this task is allowed to have this page. * Note the special case for MAP_ENTRY_COW * pages with an override. This is to implement a forced * COW for debuggers. */ if (fault_type & VM_PROT_OVERRIDE_WRITE) prot = entry->max_protection; else prot = entry->protection; fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); if ((fault_type & prot) != fault_type) { rv = KERN_PROTECTION_FAILURE; goto done; } if ((entry->eflags & MAP_ENTRY_USER_WIRED) && (entry->eflags & MAP_ENTRY_COW) && (fault_type & VM_PROT_WRITE) && (fault_typea & VM_PROT_OVERRIDE_WRITE) == 0) { rv = KERN_PROTECTION_FAILURE; goto done; } /* * If this page is not pageable, we have to get it for all possible * accesses. */ *wired = (entry->wired_count != 0); if (*wired) prot = fault_type = entry->protection; /* * Virtual page tables may need to update the accessed (A) bit * in a page table entry. Upgrade the fault to a write fault for * that case if the map will support it. If the map does not support * it the page table entry simply will not be updated. */ if (entry->maptype == VM_MAPTYPE_VPAGETABLE) { if (prot & VM_PROT_WRITE) fault_type |= VM_PROT_WRITE; } /* * If the entry was copy-on-write, we either ... */ if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { /* * If we want to write the page, we may as well handle that * now since we've got the map locked. * * If we don't need to write the page, we just demote the * permissions allowed. */ if (fault_type & VM_PROT_WRITE) { /* * Make a new object, and place it in the object * chain. Note that no new references have appeared * -- one just moved from the map to the new * object. */ if (use_read_lock && vm_map_lock_upgrade(map)) { use_read_lock = 0; goto RetryLookup; } use_read_lock = 0; vm_map_entry_shadow(entry); } else { /* * We're attempting to read a copy-on-write page -- * don't allow writes. */ prot &= ~VM_PROT_WRITE; } } /* * Create an object if necessary. */ if (entry->object.vm_object == NULL && !map->system_map) { if (use_read_lock && vm_map_lock_upgrade(map)) { use_read_lock = 0; goto RetryLookup; } use_read_lock = 0; vm_map_entry_allocate_object(entry); } /* * Return the object/offset from this entry. If the entry was * copy-on-write or empty, it has been fixed up. */ *pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset); *object = entry->object.vm_object; /* * Return whether this is the only map sharing this data. On * success we return with a read lock held on the map. On failure * we return with the map unlocked. */ *out_prot = prot; done: if (rv == KERN_SUCCESS) { if (use_read_lock == 0) vm_map_lock_downgrade(map); } else if (use_read_lock) { vm_map_unlock_read(map); } else { vm_map_unlock(map); } return (rv); } /* * vm_map_lookup_done: * * Releases locks acquired by a vm_map_lookup * (according to the handle returned by that lookup). */ void vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry, int count) { /* * Unlock the main-level map */ vm_map_unlock_read(map); if (count) vm_map_entry_release(count); } #include "opt_ddb.h" #ifdef DDB #include #include /* * vm_map_print: [ debug ] */ DB_SHOW_COMMAND(map, vm_map_print) { static int nlines; /* XXX convert args. */ vm_map_t map = (vm_map_t)addr; boolean_t full = have_addr; vm_map_entry_t entry; db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n", (void *)map, (void *)map->pmap, map->nentries, map->timestamp); nlines++; if (!full && db_indent) return; db_indent += 2; for (entry = map->header.next; entry != &map->header; entry = entry->next) { db_iprintf("map entry %p: start=%p, end=%p\n", (void *)entry, (void *)entry->start, (void *)entry->end); nlines++; { static char *inheritance_name[4] = {"share", "copy", "none", "donate_copy"}; db_iprintf(" prot=%x/%x/%s", entry->protection, entry->max_protection, inheritance_name[(int)(unsigned char)entry->inheritance]); if (entry->wired_count != 0) db_printf(", wired"); } if (entry->maptype == VM_MAPTYPE_SUBMAP) { /* XXX no %qd in kernel. Truncate entry->offset. */ db_printf(", share=%p, offset=0x%lx\n", (void *)entry->object.sub_map, (long)entry->offset); nlines++; if ((entry->prev == &map->header) || (entry->prev->object.sub_map != entry->object.sub_map)) { db_indent += 2; vm_map_print((db_expr_t)(intptr_t) entry->object.sub_map, full, 0, NULL); db_indent -= 2; } } else { /* XXX no %qd in kernel. Truncate entry->offset. */ db_printf(", object=%p, offset=0x%lx", (void *)entry->object.vm_object, (long)entry->offset); if (entry->eflags & MAP_ENTRY_COW) db_printf(", copy (%s)", (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); db_printf("\n"); nlines++; if ((entry->prev == &map->header) || (entry->prev->object.vm_object != entry->object.vm_object)) { db_indent += 2; vm_object_print((db_expr_t)(intptr_t) entry->object.vm_object, full, 0, NULL); nlines += 4; db_indent -= 2; } } } db_indent -= 2; if (db_indent == 0) nlines = 0; } DB_SHOW_COMMAND(procvm, procvm) { struct proc *p; if (have_addr) { p = (struct proc *) addr; } else { p = curproc; } db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n", (void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map, (void *)vmspace_pmap(p->p_vmspace)); vm_map_print((db_expr_t)(intptr_t)&p->p_vmspace->vm_map, 1, 0, NULL); } #endif /* DDB */