/*- * 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. * 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. */ /* * Virtual memory mapping module. */ #include __FBSDID("$FreeBSD$"); #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 #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 self-adjusting binary search tree of these * entries 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 struct mtx map_sleep_mtx; static uma_zone_t mapentzone; static uma_zone_t kmapentzone; static uma_zone_t mapzone; static uma_zone_t vmspace_zone; static int vmspace_zinit(void *mem, int size, int flags); static int vm_map_zinit(void *mem, int ize, int flags); static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max); static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map); static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry); static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry); #ifdef INVARIANTS static void vm_map_zdtor(void *mem, int size, void *arg); static void vmspace_zdtor(void *mem, int size, void *arg); #endif static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow); static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, vm_offset_t failed_addr); #define ENTRY_CHARGED(e) ((e)->cred != NULL || \ ((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \ !((e)->eflags & MAP_ENTRY_NEEDS_COPY))) /* * PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type * stable. */ #define PROC_VMSPACE_LOCK(p) do { } while (0) #define PROC_VMSPACE_UNLOCK(p) do { } while (0) /* * 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_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) { mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF); mapzone = uma_zcreate("MAP", sizeof(struct vm_map), NULL, #ifdef INVARIANTS vm_map_zdtor, #else NULL, #endif vm_map_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); uma_prealloc(mapzone, MAX_KMAP); kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_MTXCLASS | UMA_ZONE_VM); mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL, #ifdef INVARIANTS vmspace_zdtor, #else NULL, #endif vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); } static int vmspace_zinit(void *mem, int size, int flags) { struct vmspace *vm; vm = (struct vmspace *)mem; vm->vm_map.pmap = NULL; (void)vm_map_zinit(&vm->vm_map, sizeof(vm->vm_map), flags); PMAP_LOCK_INIT(vmspace_pmap(vm)); return (0); } static int vm_map_zinit(void *mem, int size, int flags) { vm_map_t map; map = (vm_map_t)mem; memset(map, 0, sizeof(*map)); mtx_init(&map->system_mtx, "vm map (system)", NULL, MTX_DEF | MTX_DUPOK); sx_init(&map->lock, "vm map (user)"); return (0); } #ifdef INVARIANTS static void vmspace_zdtor(void *mem, int size, void *arg) { struct vmspace *vm; vm = (struct vmspace *)mem; vm_map_zdtor(&vm->vm_map, sizeof(vm->vm_map), arg); } static void vm_map_zdtor(void *mem, int size, void *arg) { vm_map_t map; map = (vm_map_t)mem; KASSERT(map->nentries == 0, ("map %p nentries == %d on free.", map, map->nentries)); KASSERT(map->size == 0, ("map %p size == %lu on free.", map, (unsigned long)map->size)); } #endif /* INVARIANTS */ /* * Allocate a vmspace structure, including a vm_map and pmap, * and initialize those structures. The refcnt is set to 1. * * If 'pinit' is NULL then the embedded pmap is initialized via pmap_pinit(). */ struct vmspace * vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit) { struct vmspace *vm; vm = uma_zalloc(vmspace_zone, M_WAITOK); KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL")); if (pinit == NULL) pinit = &pmap_pinit; if (!pinit(vmspace_pmap(vm))) { uma_zfree(vmspace_zone, vm); return (NULL); } CTR1(KTR_VM, "vmspace_alloc: %p", vm); _vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max); vm->vm_refcnt = 1; vm->vm_shm = NULL; vm->vm_swrss = 0; vm->vm_tsize = 0; vm->vm_dsize = 0; vm->vm_ssize = 0; vm->vm_taddr = 0; vm->vm_daddr = 0; vm->vm_maxsaddr = 0; return (vm); } #ifdef RACCT static void vmspace_container_reset(struct proc *p) { PROC_LOCK(p); racct_set(p, RACCT_DATA, 0); racct_set(p, RACCT_STACK, 0); racct_set(p, RACCT_RSS, 0); racct_set(p, RACCT_MEMLOCK, 0); racct_set(p, RACCT_VMEM, 0); PROC_UNLOCK(p); } #endif static inline void vmspace_dofree(struct vmspace *vm) { CTR1(KTR_VM, "vmspace_free: %p", vm); /* * Make sure any SysV shm is freed, it might not have been in * exit1(). */ shmexit(vm); /* * 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. */ (void)vm_map_remove(&vm->vm_map, vm->vm_map.min_offset, vm->vm_map.max_offset); pmap_release(vmspace_pmap(vm)); vm->vm_map.pmap = NULL; uma_zfree(vmspace_zone, vm); } void vmspace_free(struct vmspace *vm) { WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "vmspace_free() called with non-sleepable lock held"); if (vm->vm_refcnt == 0) panic("vmspace_free: attempt to free already freed vmspace"); if (atomic_fetchadd_int(&vm->vm_refcnt, -1) == 1) vmspace_dofree(vm); } void vmspace_exitfree(struct proc *p) { struct vmspace *vm; PROC_VMSPACE_LOCK(p); vm = p->p_vmspace; p->p_vmspace = NULL; PROC_VMSPACE_UNLOCK(p); KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace")); vmspace_free(vm); } void vmspace_exit(struct thread *td) { int refcnt; struct vmspace *vm; struct proc *p; /* * Release user portion of address space. * This releases references to vnodes, * which could cause I/O if the file has been unlinked. * Need to do this early enough that we can still sleep. * * The last exiting process to reach this point releases as * much of the environment as it can. vmspace_dofree() is the * slower fallback in case another process had a temporary * reference to the vmspace. */ p = td->td_proc; vm = p->p_vmspace; atomic_add_int(&vmspace0.vm_refcnt, 1); do { refcnt = vm->vm_refcnt; if (refcnt > 1 && p->p_vmspace != &vmspace0) { /* Switch now since other proc might free vmspace */ PROC_VMSPACE_LOCK(p); p->p_vmspace = &vmspace0; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); } } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt - 1)); if (refcnt == 1) { if (p->p_vmspace != vm) { /* vmspace not yet freed, switch back */ PROC_VMSPACE_LOCK(p); p->p_vmspace = vm; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); } pmap_remove_pages(vmspace_pmap(vm)); /* Switch now since this proc will free vmspace */ PROC_VMSPACE_LOCK(p); p->p_vmspace = &vmspace0; PROC_VMSPACE_UNLOCK(p); pmap_activate(td); vmspace_dofree(vm); } #ifdef RACCT if (racct_enable) vmspace_container_reset(p); #endif } /* Acquire reference to vmspace owned by another process. */ struct vmspace * vmspace_acquire_ref(struct proc *p) { struct vmspace *vm; int refcnt; PROC_VMSPACE_LOCK(p); vm = p->p_vmspace; if (vm == NULL) { PROC_VMSPACE_UNLOCK(p); return (NULL); } do { refcnt = vm->vm_refcnt; if (refcnt <= 0) { /* Avoid 0->1 transition */ PROC_VMSPACE_UNLOCK(p); return (NULL); } } while (!atomic_cmpset_int(&vm->vm_refcnt, refcnt, refcnt + 1)); if (vm != p->p_vmspace) { PROC_VMSPACE_UNLOCK(p); vmspace_free(vm); return (NULL); } PROC_VMSPACE_UNLOCK(p); return (vm); } void _vm_map_lock(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_lock_flags_(&map->system_mtx, 0, file, line); else sx_xlock_(&map->lock, file, line); map->timestamp++; } static void vm_map_process_deferred(void) { struct thread *td; vm_map_entry_t entry, next; vm_object_t object; td = curthread; entry = td->td_map_def_user; td->td_map_def_user = NULL; while (entry != NULL) { next = entry->next; if ((entry->eflags & MAP_ENTRY_VN_WRITECNT) != 0) { /* * Decrement the object's writemappings and * possibly the vnode's v_writecount. */ KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0, ("Submap with writecount")); object = entry->object.vm_object; KASSERT(object != NULL, ("No object for writecount")); vnode_pager_release_writecount(object, entry->start, entry->end); } vm_map_entry_deallocate(entry, FALSE); entry = next; } } void _vm_map_unlock(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else { sx_xunlock_(&map->lock, file, line); vm_map_process_deferred(); } } void _vm_map_lock_read(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_lock_flags_(&map->system_mtx, 0, file, line); else sx_slock_(&map->lock, file, line); } void _vm_map_unlock_read(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else { sx_sunlock_(&map->lock, file, line); vm_map_process_deferred(); } } int _vm_map_trylock(vm_map_t map, const char *file, int line) { int error; error = map->system_map ? !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : !sx_try_xlock_(&map->lock, file, line); if (error == 0) map->timestamp++; return (error == 0); } int _vm_map_trylock_read(vm_map_t map, const char *file, int line) { int error; error = map->system_map ? !mtx_trylock_flags_(&map->system_mtx, 0, file, line) : !sx_try_slock_(&map->lock, file, line); return (error == 0); } /* * _vm_map_lock_upgrade: [ internal use only ] * * Tries to upgrade a read (shared) lock on the specified map to a write * (exclusive) lock. Returns the value "0" if the upgrade succeeds and a * non-zero value if the upgrade fails. If the upgrade fails, the map is * returned without a read or write lock held. * * Requires that the map be read locked. */ int _vm_map_lock_upgrade(vm_map_t map, const char *file, int line) { unsigned int last_timestamp; if (map->system_map) { mtx_assert_(&map->system_mtx, MA_OWNED, file, line); } else { if (!sx_try_upgrade_(&map->lock, file, line)) { last_timestamp = map->timestamp; sx_sunlock_(&map->lock, file, line); vm_map_process_deferred(); /* * If the map's timestamp does not change while the * map is unlocked, then the upgrade succeeds. */ sx_xlock_(&map->lock, file, line); if (last_timestamp != map->timestamp) { sx_xunlock_(&map->lock, file, line); return (1); } } } map->timestamp++; return (0); } void _vm_map_lock_downgrade(vm_map_t map, const char *file, int line) { if (map->system_map) { mtx_assert_(&map->system_mtx, MA_OWNED, file, line); } else sx_downgrade_(&map->lock, file, line); } /* * vm_map_locked: * * Returns a non-zero value if the caller holds a write (exclusive) lock * on the specified map and the value "0" otherwise. */ int vm_map_locked(vm_map_t map) { if (map->system_map) return (mtx_owned(&map->system_mtx)); else return (sx_xlocked(&map->lock)); } #ifdef INVARIANTS static void _vm_map_assert_locked(vm_map_t map, const char *file, int line) { if (map->system_map) mtx_assert_(&map->system_mtx, MA_OWNED, file, line); else sx_assert_(&map->lock, SA_XLOCKED, file, line); } #define VM_MAP_ASSERT_LOCKED(map) \ _vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE) #else #define VM_MAP_ASSERT_LOCKED(map) #endif /* * _vm_map_unlock_and_wait: * * Atomically releases the lock on the specified map and puts the calling * thread to sleep. The calling thread will remain asleep until either * vm_map_wakeup() is performed on the map or the specified timeout is * exceeded. * * WARNING! This function does not perform deferred deallocations of * objects and map entries. Therefore, the calling thread is expected to * reacquire the map lock after reawakening and later perform an ordinary * unlock operation, such as vm_map_unlock(), before completing its * operation on the map. */ int _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line) { mtx_lock(&map_sleep_mtx); if (map->system_map) mtx_unlock_flags_(&map->system_mtx, 0, file, line); else sx_xunlock_(&map->lock, file, line); return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps", timo)); } /* * vm_map_wakeup: * * Awaken any threads that have slept on the map using * vm_map_unlock_and_wait(). */ void vm_map_wakeup(vm_map_t map) { /* * Acquire and release map_sleep_mtx to prevent a wakeup() * from being performed (and lost) between the map unlock * and the msleep() in _vm_map_unlock_and_wait(). */ mtx_lock(&map_sleep_mtx); mtx_unlock(&map_sleep_mtx); wakeup(&map->root); } void vm_map_busy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); map->busy++; } void vm_map_unbusy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); KASSERT(map->busy, ("vm_map_unbusy: not busy")); if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) { vm_map_modflags(map, 0, MAP_BUSY_WAKEUP); wakeup(&map->busy); } } void vm_map_wait_busy(vm_map_t map) { VM_MAP_ASSERT_LOCKED(map); while (map->busy) { vm_map_modflags(map, MAP_BUSY_WAKEUP, 0); if (map->system_map) msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0); else sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0); } map->timestamp++; } long vmspace_resident_count(struct vmspace *vmspace) { return pmap_resident_count(vmspace_pmap(vmspace)); } /* * 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(pmap_t pmap, vm_offset_t min, vm_offset_t max) { vm_map_t result; result = uma_zalloc(mapzone, M_WAITOK); CTR1(KTR_VM, "vm_map_create: %p", result); _vm_map_init(result, pmap, min, max); return (result); } /* * Initialize an existing vm_map structure * such as that in the vmspace structure. */ static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) { map->header.next = map->header.prev = &map->header; map->needs_wakeup = FALSE; map->system_map = 0; map->pmap = pmap; map->min_offset = min; map->max_offset = max; map->flags = 0; map->root = NULL; map->timestamp = 0; map->busy = 0; } void vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max) { _vm_map_init(map, pmap, min, max); mtx_init(&map->system_mtx, "system map", NULL, MTX_DEF | MTX_DUPOK); sx_init(&map->lock, "user map"); } /* * vm_map_entry_dispose: [ internal use only ] * * Inverse of vm_map_entry_create. */ static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry) { uma_zfree(map->system_map ? kmapentzone : mapentzone, entry); } /* * vm_map_entry_create: [ internal use only ] * * Allocates a VM map entry for insertion. * No entry fields are filled in. */ static vm_map_entry_t vm_map_entry_create(vm_map_t map) { vm_map_entry_t new_entry; if (map->system_map) new_entry = uma_zalloc(kmapentzone, M_NOWAIT); else new_entry = uma_zalloc(mapentzone, M_WAITOK); if (new_entry == NULL) panic("vm_map_entry_create: kernel resources exhausted"); return (new_entry); } /* * vm_map_entry_set_behavior: * * Set the expected access behavior, either normal, random, or * sequential. */ static inline void vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior) { entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) | (behavior & MAP_ENTRY_BEHAV_MASK); } /* * vm_map_entry_set_max_free: * * Set the max_free field in a vm_map_entry. */ static inline void vm_map_entry_set_max_free(vm_map_entry_t entry) { entry->max_free = entry->adj_free; if (entry->left != NULL && entry->left->max_free > entry->max_free) entry->max_free = entry->left->max_free; if (entry->right != NULL && entry->right->max_free > entry->max_free) entry->max_free = entry->right->max_free; } /* * vm_map_entry_splay: * * The Sleator and Tarjan top-down splay algorithm with the * following variation. Max_free must be computed bottom-up, so * on the downward pass, maintain the left and right spines in * reverse order. Then, make a second pass up each side to fix * the pointers and compute max_free. The time bound is O(log n) * amortized. * * The new root is the vm_map_entry containing "addr", or else an * adjacent entry (lower or higher) if addr is not in the tree. * * The map must be locked, and leaves it so. * * Returns: the new root. */ static vm_map_entry_t vm_map_entry_splay(vm_offset_t addr, vm_map_entry_t root) { vm_map_entry_t llist, rlist; vm_map_entry_t ltree, rtree; vm_map_entry_t y; /* Special case of empty tree. */ if (root == NULL) return (root); /* * Pass One: Splay down the tree until we find addr or a NULL * pointer where addr would go. llist and rlist are the two * sides in reverse order (bottom-up), with llist linked by * the right pointer and rlist linked by the left pointer in * the vm_map_entry. Wait until Pass Two to set max_free on * the two spines. */ llist = NULL; rlist = NULL; for (;;) { /* root is never NULL in here. */ if (addr < root->start) { y = root->left; if (y == NULL) break; if (addr < y->start && y->left != NULL) { /* Rotate right and put y on rlist. */ root->left = y->right; y->right = root; vm_map_entry_set_max_free(root); root = y->left; y->left = rlist; rlist = y; } else { /* Put root on rlist. */ root->left = rlist; rlist = root; root = y; } } else if (addr >= root->end) { y = root->right; if (y == NULL) break; if (addr >= y->end && y->right != NULL) { /* Rotate left and put y on llist. */ root->right = y->left; y->left = root; vm_map_entry_set_max_free(root); root = y->right; y->right = llist; llist = y; } else { /* Put root on llist. */ root->right = llist; llist = root; root = y; } } else break; } /* * Pass Two: Walk back up the two spines, flip the pointers * and set max_free. The subtrees of the root go at the * bottom of llist and rlist. */ ltree = root->left; while (llist != NULL) { y = llist->right; llist->right = ltree; vm_map_entry_set_max_free(llist); ltree = llist; llist = y; } rtree = root->right; while (rlist != NULL) { y = rlist->left; rlist->left = rtree; vm_map_entry_set_max_free(rlist); rtree = rlist; rlist = y; } /* * Final assembly: add ltree and rtree as subtrees of root. */ root->left = ltree; root->right = rtree; vm_map_entry_set_max_free(root); return (root); } /* * vm_map_entry_{un,}link: * * Insert/remove entries from maps. */ static void vm_map_entry_link(vm_map_t map, vm_map_entry_t after_where, vm_map_entry_t entry) { CTR4(KTR_VM, "vm_map_entry_link: map %p, nentries %d, entry %p, after %p", map, map->nentries, entry, after_where); VM_MAP_ASSERT_LOCKED(map); KASSERT(after_where == &map->header || after_where->end <= entry->start, ("vm_map_entry_link: prev end %jx new start %jx overlap", (uintmax_t)after_where->end, (uintmax_t)entry->start)); KASSERT(after_where->next == &map->header || entry->end <= after_where->next->start, ("vm_map_entry_link: new end %jx next start %jx overlap", (uintmax_t)entry->end, (uintmax_t)after_where->next->start)); map->nentries++; entry->prev = after_where; entry->next = after_where->next; entry->next->prev = entry; after_where->next = entry; if (after_where != &map->header) { if (after_where != map->root) vm_map_entry_splay(after_where->start, map->root); entry->right = after_where->right; entry->left = after_where; after_where->right = NULL; after_where->adj_free = entry->start - after_where->end; vm_map_entry_set_max_free(after_where); } else { entry->right = map->root; entry->left = NULL; } entry->adj_free = (entry->next == &map->header ? map->max_offset : entry->next->start) - entry->end; vm_map_entry_set_max_free(entry); map->root = entry; } static void vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry) { vm_map_entry_t next, prev, root; VM_MAP_ASSERT_LOCKED(map); if (entry != map->root) vm_map_entry_splay(entry->start, map->root); if (entry->left == NULL) root = entry->right; else { root = vm_map_entry_splay(entry->start, entry->left); root->right = entry->right; root->adj_free = (entry->next == &map->header ? map->max_offset : entry->next->start) - root->end; vm_map_entry_set_max_free(root); } map->root = root; prev = entry->prev; next = entry->next; next->prev = prev; prev->next = next; map->nentries--; CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map, map->nentries, entry); } /* * vm_map_entry_resize_free: * * Recompute the amount of free space following a vm_map_entry * and propagate that value up the tree. Call this function after * resizing a map entry in-place, that is, without a call to * vm_map_entry_link() or _unlink(). * * The map must be locked, and leaves it so. */ static void vm_map_entry_resize_free(vm_map_t map, vm_map_entry_t entry) { /* * Using splay trees without parent pointers, propagating * max_free up the tree is done by moving the entry to the * root and making the change there. */ if (entry != map->root) map->root = vm_map_entry_splay(entry->start, map->root); entry->adj_free = (entry->next == &map->header ? map->max_offset : entry->next->start) - entry->end; vm_map_entry_set_max_free(entry); } /* * 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 cur; boolean_t locked; /* * If the map is empty, then the map entry immediately preceding * "address" is the map's header. */ cur = map->root; if (cur == NULL) *entry = &map->header; else if (address >= cur->start && cur->end > address) { *entry = cur; return (TRUE); } else if ((locked = vm_map_locked(map)) || sx_try_upgrade(&map->lock)) { /* * Splay requires a write lock on the map. However, it only * restructures the binary search tree; it does not otherwise * change the map. Thus, the map's timestamp need not change * on a temporary upgrade. */ map->root = cur = vm_map_entry_splay(address, cur); if (!locked) sx_downgrade(&map->lock); /* * If "address" is contained within a map entry, the new root * is that map entry. Otherwise, the new root is a map entry * immediately before or after "address". */ if (address >= cur->start) { *entry = cur; if (cur->end > address) return (TRUE); } else *entry = cur->prev; } else /* * Since the map is only locked for read access, perform a * standard binary search tree lookup for "address". */ for (;;) { if (address < cur->start) { if (cur->left == NULL) { *entry = cur->prev; break; } cur = cur->left; } else if (cur->end > address) { *entry = cur; return (TRUE); } else { if (cur->right == NULL) { *entry = cur; break; } cur = cur->right; } } 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. * * 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, vm_object_t object, vm_ooffset_t offset, vm_offset_t start, vm_offset_t end, 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; struct ucred *cred; vm_inherit_t inheritance; boolean_t charge_prev_obj; VM_MAP_ASSERT_LOCKED(map); /* * 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; charge_prev_obj = FALSE; 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_VN_WRITECOUNT) protoeflags |= MAP_ENTRY_VN_WRITECNT; if (cow & MAP_INHERIT_SHARE) inheritance = VM_INHERIT_SHARE; else inheritance = VM_INHERIT_DEFAULT; cred = NULL; KASSERT((object != kmem_object && object != kernel_object) || ((object == kmem_object || object == kernel_object) && !(protoeflags & MAP_ENTRY_NEEDS_COPY)), ("kmem or kernel object and cow")); if (cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT)) goto charged; if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) && ((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) { if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start)) return (KERN_RESOURCE_SHORTAGE); KASSERT(object == NULL || (protoeflags & MAP_ENTRY_NEEDS_COPY) || object->cred == NULL, ("OVERCOMMIT: vm_map_insert o %p", object)); cred = curthread->td_ucred; crhold(cred); if (object == NULL && !(protoeflags & MAP_ENTRY_NEEDS_COPY)) charge_prev_obj = TRUE; } charged: /* Expand the kernel pmap, if necessary. */ if (map == kernel_map && end > kernel_vm_end) pmap_growkernel(end); if (object != NULL) { /* * OBJ_ONEMAPPING must be cleared unless this mapping * is trivially proven to be the only mapping for any * of the object's pages. (Object granularity * reference counting is insufficient to recognize * aliases with precision.) */ VM_OBJECT_WLOCK(object); if (object->ref_count > 1 || object->shadow_count != 0) vm_object_clear_flag(object, OBJ_ONEMAPPING); VM_OBJECT_WUNLOCK(object); } else if ((prev_entry != &map->header) && (prev_entry->eflags == protoeflags) && (cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 && (prev_entry->end == start) && (prev_entry->wired_count == 0) && (prev_entry->cred == cred || (prev_entry->object.vm_object != NULL && (prev_entry->object.vm_object->cred == cred))) && vm_object_coalesce(prev_entry->object.vm_object, prev_entry->offset, (vm_size_t)(prev_entry->end - prev_entry->start), (vm_size_t)(end - prev_entry->end), charge_prev_obj)) { /* * 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 == inheritance) && (prev_entry->protection == prot) && (prev_entry->max_protection == max)) { map->size += (end - prev_entry->end); prev_entry->end = end; vm_map_entry_resize_free(map, prev_entry); vm_map_simplify_entry(map, prev_entry); if (cred != NULL) crfree(cred); 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); if (cred != NULL && object != NULL && object->cred != NULL && !(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { /* Object already accounts for this uid. */ crfree(cred); cred = NULL; } } /* * 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); new_entry->start = start; new_entry->end = end; new_entry->cred = NULL; new_entry->eflags = protoeflags; new_entry->object.vm_object = object; new_entry->offset = offset; new_entry->avail_ssize = 0; new_entry->inheritance = inheritance; new_entry->protection = prot; new_entry->max_protection = max; new_entry->wired_count = 0; new_entry->wiring_thread = NULL; new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT; new_entry->next_read = OFF_TO_IDX(offset); KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry), ("OVERCOMMIT: vm_map_insert leaks vm_map %p", new_entry)); new_entry->cred = cred; /* * Insert the new entry into the list */ vm_map_entry_link(map, prev_entry, new_entry); map->size += new_entry->end - new_entry->start; /* * It may be possible to merge the new entry with the next and/or * previous entries. However, due to MAP_STACK_* being a hack, a * panic can result from merging such entries. */ if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0) vm_map_simplify_entry(map, new_entry); if (cow & (MAP_PREFAULT|MAP_PREFAULT_PARTIAL)) { vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset), end - start, cow & MAP_PREFAULT_PARTIAL); } return (KERN_SUCCESS); } /* * vm_map_findspace: * * Find the first fit (lowest VM address) for "length" free bytes * beginning at address >= start in the given map. * * In a vm_map_entry, "adj_free" is the amount of free space * adjacent (higher address) to this entry, and "max_free" is the * maximum amount of contiguous free space in its subtree. This * allows finding a free region in one path down the tree, so * O(log n) amortized with splay trees. * * The map must be locked, and leaves it so. * * Returns: 0 on success, and starting address in *addr, * 1 if insufficient space. */ int vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, vm_offset_t *addr) /* OUT */ { vm_map_entry_t entry; vm_offset_t st; /* * Request must fit within min/max VM address and must avoid * address wrap. */ if (start < map->min_offset) start = map->min_offset; if (start + length > map->max_offset || start + length < start) return (1); /* Empty tree means wide open address space. */ if (map->root == NULL) { *addr = start; return (0); } /* * After splay, if start comes before root node, then there * must be a gap from start to the root. */ map->root = vm_map_entry_splay(start, map->root); if (start + length <= map->root->start) { *addr = start; return (0); } /* * Root is the last node that might begin its gap before * start, and this is the last comparison where address * wrap might be a problem. */ st = (start > map->root->end) ? start : map->root->end; if (length <= map->root->end + map->root->adj_free - st) { *addr = st; return (0); } /* With max_free, can immediately tell if no solution. */ entry = map->root->right; if (entry == NULL || length > entry->max_free) return (1); /* * Search the right subtree in the order: left subtree, root, * right subtree (first fit). The previous splay implies that * all regions in the right subtree have addresses > start. */ while (entry != NULL) { if (entry->left != NULL && entry->left->max_free >= length) entry = entry->left; else if (entry->adj_free >= length) { *addr = entry->end; return (0); } else entry = entry->right; } /* Can't get here, so panic if we do. */ panic("vm_map_findspace: max_free corrupt"); } int vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t start, vm_size_t length, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t end; int result; end = start + length; KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || object == NULL, ("vm_map_fixed: non-NULL backing object for stack")); vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if ((cow & MAP_CHECK_EXCL) == 0) vm_map_delete(map, start, end); if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { result = vm_map_stack_locked(map, start, length, sgrowsiz, prot, max, cow); } else { result = vm_map_insert(map, object, offset, start, end, prot, max, cow); } vm_map_unlock(map); return (result); } /* * 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, /* IN/OUT */ vm_size_t length, vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max, int cow) { vm_offset_t alignment, initial_addr, start; int result; KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 || object == NULL, ("vm_map_find: non-NULL backing object for stack")); if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL || (object->flags & OBJ_COLORED) == 0)) find_space = VMFS_ANY_SPACE; if (find_space >> 8 != 0) { KASSERT((find_space & 0xff) == 0, ("bad VMFS flags")); alignment = (vm_offset_t)1 << (find_space >> 8); } else alignment = 0; initial_addr = *addr; again: start = initial_addr; vm_map_lock(map); do { if (find_space != VMFS_NO_SPACE) { if (vm_map_findspace(map, start, length, addr) || (max_addr != 0 && *addr + length > max_addr)) { vm_map_unlock(map); if (find_space == VMFS_OPTIMAL_SPACE) { find_space = VMFS_ANY_SPACE; goto again; } return (KERN_NO_SPACE); } switch (find_space) { case VMFS_SUPER_SPACE: case VMFS_OPTIMAL_SPACE: pmap_align_superpage(object, offset, addr, length); break; case VMFS_ANY_SPACE: break; default: if ((*addr & (alignment - 1)) != 0) { *addr &= ~(alignment - 1); *addr += alignment; } break; } start = *addr; } if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) { result = vm_map_stack_locked(map, start, length, sgrowsiz, prot, max, cow); } else { result = vm_map_insert(map, object, offset, start, start + length, prot, max, cow); } } while (result == KERN_NO_SPACE && find_space != VMFS_NO_SPACE && find_space != VMFS_ANY_SPACE); vm_map_unlock(map); 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. */ void vm_map_simplify_entry(vm_map_t map, vm_map_entry_t entry) { vm_map_entry_t next, prev; vm_size_t prevsize, esize; if (entry->eflags & (MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP)) return; prev = entry->prev; if (prev != &map->header) { prevsize = prev->end - prev->start; if ( (prev->end == entry->start) && (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) && (prev->cred == entry->cred)) { vm_map_entry_unlink(map, prev); entry->start = prev->start; entry->offset = prev->offset; if (entry->prev != &map->header) vm_map_entry_resize_free(map, entry->prev); /* * If the backing object is a vnode object, * vm_object_deallocate() calls vrele(). * However, vrele() does not lock the vnode * because the vnode has additional * references. Thus, the map lock can be kept * without causing a lock-order reversal with * the vnode lock. * * Since we count the number of virtual page * mappings in object->un_pager.vnp.writemappings, * the writemappings value should not be adjusted * when the entry is disposed of. */ if (prev->object.vm_object) vm_object_deallocate(prev->object.vm_object); if (prev->cred != NULL) crfree(prev->cred); vm_map_entry_dispose(map, prev); } } next = entry->next; if (next != &map->header) { esize = entry->end - entry->start; if ((entry->end == next->start) && (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) && (next->cred == entry->cred)) { vm_map_entry_unlink(map, next); entry->end = next->end; vm_map_entry_resize_free(map, entry); /* * See comment above. */ if (next->object.vm_object) vm_object_deallocate(next->object.vm_object); if (next->cred != NULL) crfree(next->cred); vm_map_entry_dispose(map, next); } } } /* * 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) \ { \ if (startaddr > entry->start) \ _vm_map_clip_start(map, entry, startaddr); \ } /* * 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) { vm_map_entry_t new_entry; VM_MAP_ASSERT_LOCKED(map); /* * 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); /* * 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_object_t object; object = vm_object_allocate(OBJT_DEFAULT, atop(entry->end - entry->start)); entry->object.vm_object = object; entry->offset = 0; if (entry->cred != NULL) { object->cred = entry->cred; object->charge = entry->end - entry->start; entry->cred = NULL; } } else if (entry->object.vm_object != NULL && ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && entry->cred != NULL) { VM_OBJECT_WLOCK(entry->object.vm_object); KASSERT(entry->object.vm_object->cred == NULL, ("OVERCOMMIT: vm_entry_clip_start: both cred e %p", entry)); entry->object.vm_object->cred = entry->cred; entry->object.vm_object->charge = entry->end - entry->start; VM_OBJECT_WUNLOCK(entry->object.vm_object); entry->cred = NULL; } new_entry = vm_map_entry_create(map); *new_entry = *entry; new_entry->end = start; entry->offset += (start - entry->start); entry->start = start; if (new_entry->cred != NULL) crhold(entry->cred); vm_map_entry_link(map, entry->prev, new_entry); if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { vm_object_reference(new_entry->object.vm_object); /* * The object->un_pager.vnp.writemappings for the * object of MAP_ENTRY_VN_WRITECNT type entry shall be * kept as is here. The virtual pages are * re-distributed among the clipped entries, so the sum is * left the same. */ } } /* * 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) \ { \ if ((endaddr) < (entry->end)) \ _vm_map_clip_end((map), (entry), (endaddr)); \ } /* * 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) { vm_map_entry_t new_entry; VM_MAP_ASSERT_LOCKED(map); /* * 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_object_t object; object = vm_object_allocate(OBJT_DEFAULT, atop(entry->end - entry->start)); entry->object.vm_object = object; entry->offset = 0; if (entry->cred != NULL) { object->cred = entry->cred; object->charge = entry->end - entry->start; entry->cred = NULL; } } else if (entry->object.vm_object != NULL && ((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) && entry->cred != NULL) { VM_OBJECT_WLOCK(entry->object.vm_object); KASSERT(entry->object.vm_object->cred == NULL, ("OVERCOMMIT: vm_entry_clip_end: both cred e %p", entry)); entry->object.vm_object->cred = entry->cred; entry->object.vm_object->charge = entry->end - entry->start; VM_OBJECT_WUNLOCK(entry->object.vm_object); entry->cred = NULL; } /* * Create a new entry and insert it AFTER the specified entry */ new_entry = vm_map_entry_create(map); *new_entry = *entry; new_entry->start = entry->end = end; new_entry->offset += (end - entry->start); if (new_entry->cred != NULL) crhold(entry->cred); vm_map_entry_link(map, entry, new_entry); if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { vm_object_reference(new_entry->object.vm_object); } } /* * 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; 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); } else entry = entry->next; vm_map_clip_end(map, entry, end); if ((entry->start == start) && (entry->end == end) && ((entry->eflags & MAP_ENTRY_COW) == 0) && (entry->object.vm_object == NULL)) { entry->object.sub_map = submap; entry->eflags |= MAP_ENTRY_IS_SUB_MAP; result = KERN_SUCCESS; } vm_map_unlock(map); return (result); } /* * The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified */ #define MAX_INIT_PT 96 /* * vm_map_pmap_enter: * * Preload the specified map's pmap with mappings to the specified * object's memory-resident pages. No further physical pages are * allocated, and no further virtual pages are retrieved from secondary * storage. If the specified flags include MAP_PREFAULT_PARTIAL, then a * limited number of page mappings are created at the low-end of the * specified address range. (For this purpose, a superpage mapping * counts as one page mapping.) Otherwise, all resident pages within * the specified address range are mapped. Because these mappings are * being created speculatively, cached pages are not reactivated and * mapped. */ void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot, vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags) { vm_offset_t start; vm_page_t p, p_start; vm_pindex_t mask, psize, threshold, tmpidx; if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL) return; VM_OBJECT_RLOCK(object); if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { VM_OBJECT_RUNLOCK(object); VM_OBJECT_WLOCK(object); if (object->type == OBJT_DEVICE || object->type == OBJT_SG) { pmap_object_init_pt(map->pmap, addr, object, pindex, size); VM_OBJECT_WUNLOCK(object); return; } VM_OBJECT_LOCK_DOWNGRADE(object); } psize = atop(size); if (psize + pindex > object->size) { if (object->size < pindex) { VM_OBJECT_RUNLOCK(object); return; } psize = object->size - pindex; } start = 0; p_start = NULL; threshold = MAX_INIT_PT; p = vm_page_find_least(object, pindex); /* * Assert: the variable p is either (1) the page with the * least pindex greater than or equal to the parameter pindex * or (2) NULL. */ for (; p != NULL && (tmpidx = p->pindex - pindex) < psize; p = TAILQ_NEXT(p, listq)) { /* * don't allow an madvise to blow away our really * free pages allocating pv entries. */ if (((flags & MAP_PREFAULT_MADVISE) != 0 && cnt.v_free_count < cnt.v_free_reserved) || ((flags & MAP_PREFAULT_PARTIAL) != 0 && tmpidx >= threshold)) { psize = tmpidx; break; } if (p->valid == VM_PAGE_BITS_ALL) { if (p_start == NULL) { start = addr + ptoa(tmpidx); p_start = p; } /* Jump ahead if a superpage mapping is possible. */ if (p->psind > 0 && ((addr + ptoa(tmpidx)) & (pagesizes[p->psind] - 1)) == 0) { mask = atop(pagesizes[p->psind]) - 1; if (tmpidx + mask < psize && vm_page_ps_is_valid(p)) { p += mask; threshold += mask; } } } else if (p_start != NULL) { pmap_enter_object(map->pmap, start, addr + ptoa(tmpidx), p_start, prot); p_start = NULL; } } if (p_start != NULL) pmap_enter_object(map->pmap, start, addr + ptoa(psize), p_start, prot); VM_OBJECT_RUNLOCK(object); } /* * 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. */ 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, entry; vm_object_t obj; struct ucred *cred; vm_prot_t old_prot; if (start == end) return (KERN_SUCCESS); 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); } else { entry = entry->next; } /* * Make a first pass to check for protection violations. */ current = entry; while ((current != &map->header) && (current->start < end)) { if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_unlock(map); return (KERN_INVALID_ARGUMENT); } if ((new_prot & current->max_protection) != new_prot) { vm_map_unlock(map); return (KERN_PROTECTION_FAILURE); } current = current->next; } /* * Do an accounting pass for private read-only mappings that * now will do cow due to allowed write (e.g. debugger sets * breakpoint on text segment) */ for (current = entry; (current != &map->header) && (current->start < end); current = current->next) { vm_map_clip_end(map, current, end); if (set_max || ((new_prot & ~(current->protection)) & VM_PROT_WRITE) == 0 || ENTRY_CHARGED(current)) { continue; } cred = curthread->td_ucred; obj = current->object.vm_object; if (obj == NULL || (current->eflags & MAP_ENTRY_NEEDS_COPY)) { if (!swap_reserve(current->end - current->start)) { vm_map_unlock(map); return (KERN_RESOURCE_SHORTAGE); } crhold(cred); current->cred = cred; continue; } VM_OBJECT_WLOCK(obj); if (obj->type != OBJT_DEFAULT && obj->type != OBJT_SWAP) { VM_OBJECT_WUNLOCK(obj); continue; } /* * Charge for the whole object allocation now, since * we cannot distinguish between non-charged and * charged clipped mapping of the same object later. */ KASSERT(obj->charge == 0, ("vm_map_protect: object %p overcharged (entry %p)", obj, current)); if (!swap_reserve(ptoa(obj->size))) { VM_OBJECT_WUNLOCK(obj); vm_map_unlock(map); return (KERN_RESOURCE_SHORTAGE); } crhold(cred); obj->cred = cred; obj->charge = ptoa(obj->size); VM_OBJECT_WUNLOCK(obj); } /* * Go back and fix up protections. [Note that clipping is not * necessary the second time.] */ current = entry; while ((current != &map->header) && (current->start < end)) { old_prot = current->protection; if (set_max) current->protection = (current->max_protection = new_prot) & old_prot; else current->protection = new_prot; /* * For user wired map entries, the normal lazy evaluation of * write access upgrades through soft page faults is * undesirable. Instead, immediately copy any pages that are * copy-on-write and enable write access in the physical map. */ if ((current->eflags & MAP_ENTRY_USER_WIRED) != 0 && (current->protection & VM_PROT_WRITE) != 0 && (old_prot & VM_PROT_WRITE) == 0) vm_fault_copy_entry(map, map, current, current, NULL); /* * When restricting access, update the physical map. Worry * about copy-on-write here. */ if ((old_prot & ~current->protection) != 0) { #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); current = current->next; } vm_map_unlock(map); 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. */ int vm_map_madvise( vm_map_t map, vm_offset_t start, vm_offset_t end, int behav) { vm_map_entry_t current, entry; int modify_map = 0; /* * 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. */ switch(behav) { case MADV_NORMAL: case MADV_SEQUENTIAL: case MADV_RANDOM: case MADV_NOSYNC: case MADV_AUTOSYNC: case MADV_NOCORE: case MADV_CORE: if (start == end) return (KERN_SUCCESS); modify_map = 1; vm_map_lock(map); break; case MADV_WILLNEED: case MADV_DONTNEED: case MADV_FREE: if (start == end) return (KERN_SUCCESS); vm_map_lock_read(map); break; default: return (KERN_INVALID_ARGUMENT); } /* * 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); } 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->eflags & MAP_ENTRY_IS_SUB_MAP) continue; vm_map_clip_end(map, current, end); 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; default: break; } vm_map_simplify_entry(map, current); } vm_map_unlock(map); } else { vm_pindex_t pstart, pend; /* * 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. */ for (current = entry; (current != &map->header) && (current->start < end); current = current->next ) { vm_offset_t useEnd, useStart; if (current->eflags & MAP_ENTRY_IS_SUB_MAP) continue; pstart = OFF_TO_IDX(current->offset); pend = pstart + atop(current->end - current->start); useStart = current->start; useEnd = current->end; if (current->start < start) { pstart += atop(start - current->start); useStart = start; } if (current->end > end) { pend -= atop(current->end - end); useEnd = end; } if (pstart >= pend) continue; /* * Perform the pmap_advise() before clearing * PGA_REFERENCED in vm_page_advise(). Otherwise, a * concurrent pmap operation, such as pmap_remove(), * could clear a reference in the pmap and set * PGA_REFERENCED on the page before the pmap_advise() * had completed. Consequently, the page would appear * referenced based upon an old reference that * occurred before this pmap_advise() ran. */ if (behav == MADV_DONTNEED || behav == MADV_FREE) pmap_advise(map->pmap, useStart, useEnd, behav); vm_object_madvise(current->object.vm_object, pstart, pend, behav); /* * Pre-populate paging structures in the * WILLNEED case. For wired entries, the * paging structures are already populated. */ if (behav == MADV_WILLNEED && current->wired_count == 0) { vm_map_pmap_enter(map, useStart, current->protection, current->object.vm_object, pstart, ptoa(pend - pstart), MAP_PREFAULT_MADVISE ); } } vm_map_unlock_read(map); } return (0); } /* * 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 vmspace_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; switch (new_inheritance) { case VM_INHERIT_NONE: case VM_INHERIT_COPY: case VM_INHERIT_SHARE: break; default: return (KERN_INVALID_ARGUMENT); } if (start == end) return (KERN_SUCCESS); 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); } else entry = temp_entry->next; while ((entry != &map->header) && (entry->start < end)) { vm_map_clip_end(map, entry, end); entry->inheritance = new_inheritance; vm_map_simplify_entry(map, entry); entry = entry->next; } vm_map_unlock(map); return (KERN_SUCCESS); } /* * vm_map_unwire: * * Implements both kernel and user unwiring. */ int vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) { vm_map_entry_t entry, first_entry, tmp_entry; vm_offset_t saved_start; unsigned int last_timestamp; int rv; boolean_t need_wakeup, result, user_unwire; if (start == end) return (KERN_SUCCESS); user_unwire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE; vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &first_entry)) { if (flags & VM_MAP_WIRE_HOLESOK) first_entry = first_entry->next; else { vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } } last_timestamp = map->timestamp; entry = first_entry; while (entry != &map->header && entry->start < end) { if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { /* * We have not yet clipped the entry. */ saved_start = (start >= entry->start) ? start : entry->start; entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; if (vm_map_unlock_and_wait(map, 0)) { /* * Allow interruption of user unwiring? */ } vm_map_lock(map); if (last_timestamp+1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. * Specifically, the entry may have been * clipped, merged, or deleted. */ if (!vm_map_lookup_entry(map, saved_start, &tmp_entry)) { if (flags & VM_MAP_WIRE_HOLESOK) tmp_entry = tmp_entry->next; else { if (saved_start == start) { /* * First_entry has been deleted. */ vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } end = saved_start; rv = KERN_INVALID_ADDRESS; goto done; } } if (entry == first_entry) first_entry = tmp_entry; else first_entry = NULL; entry = tmp_entry; } last_timestamp = map->timestamp; continue; } vm_map_clip_start(map, entry, start); vm_map_clip_end(map, entry, end); /* * Mark the entry in case the map lock is released. (See * above.) */ KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && entry->wiring_thread == NULL, ("owned map entry %p", entry)); entry->eflags |= MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = curthread; /* * Check the map for holes in the specified region. * If VM_MAP_WIRE_HOLESOK was specified, skip this check. */ if (((flags & VM_MAP_WIRE_HOLESOK) == 0) && (entry->end < end && (entry->next == &map->header || entry->next->start > entry->end))) { end = entry->end; rv = KERN_INVALID_ADDRESS; goto done; } /* * If system unwiring, require that the entry is system wired. */ if (!user_unwire && vm_map_entry_system_wired_count(entry) == 0) { end = entry->end; rv = KERN_INVALID_ARGUMENT; goto done; } entry = entry->next; } rv = KERN_SUCCESS; done: need_wakeup = FALSE; if (first_entry == NULL) { result = vm_map_lookup_entry(map, start, &first_entry); if (!result && (flags & VM_MAP_WIRE_HOLESOK)) first_entry = first_entry->next; else KASSERT(result, ("vm_map_unwire: lookup failed")); } for (entry = first_entry; entry != &map->header && entry->start < end; entry = entry->next) { /* * If VM_MAP_WIRE_HOLESOK was specified, an empty * space in the unwired region could have been mapped * while the map lock was dropped for draining * MAP_ENTRY_IN_TRANSITION. Moreover, another thread * could be simultaneously wiring this new mapping * entry. Detect these cases and skip any entries * marked as in transition by us. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || entry->wiring_thread != curthread) { KASSERT((flags & VM_MAP_WIRE_HOLESOK) != 0, ("vm_map_unwire: !HOLESOK and new/changed entry")); continue; } if (rv == KERN_SUCCESS && (!user_unwire || (entry->eflags & MAP_ENTRY_USER_WIRED))) { if (user_unwire) entry->eflags &= ~MAP_ENTRY_USER_WIRED; if (entry->wired_count == 1) vm_map_entry_unwire(map, entry); else entry->wired_count--; } KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, ("vm_map_unwire: in-transition flag missing %p", entry)); KASSERT(entry->wiring_thread == curthread, ("vm_map_unwire: alien wire %p", entry)); entry->eflags &= ~MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = NULL; if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; need_wakeup = TRUE; } vm_map_simplify_entry(map, entry); } vm_map_unlock(map); if (need_wakeup) vm_map_wakeup(map); return (rv); } /* * vm_map_wire_entry_failure: * * Handle a wiring failure on the given entry. * * The map should be locked. */ static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry, vm_offset_t failed_addr) { VM_MAP_ASSERT_LOCKED(map); KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 && entry->wired_count == 1, ("vm_map_wire_entry_failure: entry %p isn't being wired", entry)); KASSERT(failed_addr < entry->end, ("vm_map_wire_entry_failure: entry %p was fully wired", entry)); /* * If any pages at the start of this entry were successfully wired, * then unwire them. */ if (failed_addr > entry->start) { pmap_unwire(map->pmap, entry->start, failed_addr); vm_object_unwire(entry->object.vm_object, entry->offset, failed_addr - entry->start, PQ_ACTIVE); } /* * Assign an out-of-range value to represent the failure to wire this * entry. */ entry->wired_count = -1; } /* * vm_map_wire: * * Implements both kernel and user wiring. */ int vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags) { vm_map_entry_t entry, first_entry, tmp_entry; vm_offset_t faddr, saved_end, saved_start; unsigned int last_timestamp; int rv; boolean_t need_wakeup, result, user_wire; vm_prot_t prot; if (start == end) return (KERN_SUCCESS); prot = 0; if (flags & VM_MAP_WIRE_WRITE) prot |= VM_PROT_WRITE; user_wire = (flags & VM_MAP_WIRE_USER) ? TRUE : FALSE; vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); if (!vm_map_lookup_entry(map, start, &first_entry)) { if (flags & VM_MAP_WIRE_HOLESOK) first_entry = first_entry->next; else { vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } } last_timestamp = map->timestamp; entry = first_entry; while (entry != &map->header && entry->start < end) { if (entry->eflags & MAP_ENTRY_IN_TRANSITION) { /* * We have not yet clipped the entry. */ saved_start = (start >= entry->start) ? start : entry->start; entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; if (vm_map_unlock_and_wait(map, 0)) { /* * Allow interruption of user wiring? */ } vm_map_lock(map); if (last_timestamp + 1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. * Specifically, the entry may have been * clipped, merged, or deleted. */ if (!vm_map_lookup_entry(map, saved_start, &tmp_entry)) { if (flags & VM_MAP_WIRE_HOLESOK) tmp_entry = tmp_entry->next; else { if (saved_start == start) { /* * first_entry has been deleted. */ vm_map_unlock(map); return (KERN_INVALID_ADDRESS); } end = saved_start; rv = KERN_INVALID_ADDRESS; goto done; } } if (entry == first_entry) first_entry = tmp_entry; else first_entry = NULL; entry = tmp_entry; } last_timestamp = map->timestamp; continue; } vm_map_clip_start(map, entry, start); vm_map_clip_end(map, entry, end); /* * Mark the entry in case the map lock is released. (See * above.) */ KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 && entry->wiring_thread == NULL, ("owned map entry %p", entry)); entry->eflags |= MAP_ENTRY_IN_TRANSITION; entry->wiring_thread = curthread; if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || (entry->protection & prot) != prot) { entry->eflags |= MAP_ENTRY_WIRE_SKIPPED; if ((flags & VM_MAP_WIRE_HOLESOK) == 0) { end = entry->end; rv = KERN_INVALID_ADDRESS; goto done; } goto next_entry; } if (entry->wired_count == 0) { entry->wired_count++; saved_start = entry->start; saved_end = entry->end; /* * Release the map lock, relying on the in-transition * mark. Mark the map busy for fork. */ vm_map_busy(map); vm_map_unlock(map); faddr = saved_start; do { /* * Simulate a fault to get the page and enter * it into the physical map. */ if ((rv = vm_fault(map, faddr, VM_PROT_NONE, VM_FAULT_WIRE)) != KERN_SUCCESS) break; } while ((faddr += PAGE_SIZE) < saved_end); vm_map_lock(map); vm_map_unbusy(map); if (last_timestamp + 1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. The entry * may have been clipped, but NOT merged or * deleted. */ result = vm_map_lookup_entry(map, saved_start, &tmp_entry); KASSERT(result, ("vm_map_wire: lookup failed")); if (entry == first_entry) first_entry = tmp_entry; else first_entry = NULL; entry = tmp_entry; while (entry->end < saved_end) { /* * In case of failure, handle entries * that were not fully wired here; * fully wired entries are handled * later. */ if (rv != KERN_SUCCESS && faddr < entry->end) vm_map_wire_entry_failure(map, entry, faddr); entry = entry->next; } } last_timestamp = map->timestamp; if (rv != KERN_SUCCESS) { vm_map_wire_entry_failure(map, entry, faddr); end = entry->end; goto done; } } else if (!user_wire || (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { entry->wired_count++; } /* * Check the map for holes in the specified region. * If VM_MAP_WIRE_HOLESOK was specified, skip this check. */ next_entry: if (((flags & VM_MAP_WIRE_HOLESOK) == 0) && (entry->end < end && (entry->next == &map->header || entry->next->start > entry->end))) { end = entry->end; rv = KERN_INVALID_ADDRESS; goto done; } entry = entry->next; } rv = KERN_SUCCESS; done: need_wakeup = FALSE; if (first_entry == NULL) { result = vm_map_lookup_entry(map, start, &first_entry); if (!result && (flags & VM_MAP_WIRE_HOLESOK)) first_entry = first_entry->next; else KASSERT(result, ("vm_map_wire: lookup failed")); } for (entry = first_entry; entry != &map->header && entry->start < end; entry = entry->next) { if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) goto next_entry_done; /* * If VM_MAP_WIRE_HOLESOK was specified, an empty * space in the unwired region could have been mapped * while the map lock was dropped for faulting in the * pages or draining MAP_ENTRY_IN_TRANSITION. * Moreover, another thread could be simultaneously * wiring this new mapping entry. Detect these cases * and skip any entries marked as in transition by us. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 || entry->wiring_thread != curthread) { KASSERT((flags & VM_MAP_WIRE_HOLESOK) != 0, ("vm_map_wire: !HOLESOK and new/changed entry")); continue; } if (rv == KERN_SUCCESS) { if (user_wire) entry->eflags |= MAP_ENTRY_USER_WIRED; } else if (entry->wired_count == -1) { /* * Wiring failed on this entry. Thus, unwiring is * unnecessary. */ entry->wired_count = 0; } else if (!user_wire || (entry->eflags & MAP_ENTRY_USER_WIRED) == 0) { /* * Undo the wiring. Wiring succeeded on this entry * but failed on a later entry. */ if (entry->wired_count == 1) vm_map_entry_unwire(map, entry); else entry->wired_count--; } next_entry_done: KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0, ("vm_map_wire: in-transition flag missing %p", entry)); KASSERT(entry->wiring_thread == curthread, ("vm_map_wire: alien wire %p", entry)); entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WIRE_SKIPPED); entry->wiring_thread = NULL; if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) { entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP; need_wakeup = TRUE; } vm_map_simplify_entry(map, entry); } vm_map_unlock(map); if (need_wakeup) vm_map_wakeup(map); return (rv); } /* * vm_map_sync * * 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. * * If the size of the region from start to end is zero, we are * supposed to flush all modified pages within the region containing * start. Unfortunately, a region can be split or coalesced with * neighboring regions, making it difficult to determine what the * original region was. Therefore, we approximate this requirement by * flushing the current region containing start. * * Returns an error if any part of the specified range is not mapped. */ int vm_map_sync( 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; unsigned int last_timestamp; boolean_t failed; 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); } else if (start == end) { start = entry->start; end = entry->end; } /* * Make a first pass to check for user-wired memory and holes. */ for (current = entry; current != &map->header && current->start < end; current = current->next) { if (invalidate && (current->eflags & MAP_ENTRY_USER_WIRED)) { 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(map->pmap, start, end); failed = FALSE; /* * Make a second pass, cleaning/uncaching pages from the indicated * objects as we go. */ for (current = entry; current != &map->header && current->start < end;) { offset = current->offset + (start - current->start); size = (end <= current->end ? end : current->end) - start; if (current->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_t smap; vm_map_entry_t tentry; vm_size_t tsize; smap = current->object.sub_map; vm_map_lock_read(smap); (void) 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; } vm_object_reference(object); last_timestamp = map->timestamp; vm_map_unlock_read(map); if (!vm_object_sync(object, offset, size, syncio, invalidate)) failed = TRUE; start += size; vm_object_deallocate(object); vm_map_lock_read(map); if (last_timestamp == map->timestamp || !vm_map_lookup_entry(map, start, ¤t)) current = current->next; } vm_map_unlock_read(map); return (failed ? KERN_FAILURE : 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) { VM_MAP_ASSERT_LOCKED(map); KASSERT(entry->wired_count > 0, ("vm_map_entry_unwire: entry %p isn't wired", entry)); pmap_unwire(map->pmap, entry->start, entry->end); vm_object_unwire(entry->object.vm_object, entry->offset, entry->end - entry->start, PQ_ACTIVE); entry->wired_count = 0; } static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map) { if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) vm_object_deallocate(entry->object.vm_object); uma_zfree(system_map ? kmapentzone : mapentzone, 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) { vm_object_t object; vm_pindex_t offidxstart, offidxend, count, size1; vm_ooffset_t size; vm_map_entry_unlink(map, entry); object = entry->object.vm_object; size = entry->end - entry->start; map->size -= size; if (entry->cred != NULL) { swap_release_by_cred(size, entry->cred); crfree(entry->cred); } if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0 && (object != NULL)) { KASSERT(entry->cred == NULL || object->cred == NULL || (entry->eflags & MAP_ENTRY_NEEDS_COPY), ("OVERCOMMIT vm_map_entry_delete: both cred %p", entry)); count = OFF_TO_IDX(size); offidxstart = OFF_TO_IDX(entry->offset); offidxend = offidxstart + count; VM_OBJECT_WLOCK(object); if (object->ref_count != 1 && ((object->flags & (OBJ_NOSPLIT|OBJ_ONEMAPPING)) == OBJ_ONEMAPPING || object == kernel_object || object == kmem_object)) { vm_object_collapse(object); /* * The option OBJPR_NOTMAPPED can be passed here * because vm_map_delete() already performed * pmap_remove() on the only mapping to this range * of pages. */ vm_object_page_remove(object, offidxstart, offidxend, OBJPR_NOTMAPPED); if (object->type == OBJT_SWAP) swap_pager_freespace(object, offidxstart, count); if (offidxend >= object->size && offidxstart < object->size) { size1 = object->size; object->size = offidxstart; if (object->cred != NULL) { size1 -= object->size; KASSERT(object->charge >= ptoa(size1), ("vm_map_entry_delete: object->charge < 0")); swap_release_by_cred(ptoa(size1), object->cred); object->charge -= ptoa(size1); } } } VM_OBJECT_WUNLOCK(object); } else entry->object.vm_object = NULL; if (map->system_map) vm_map_entry_deallocate(entry, TRUE); else { entry->next = curthread->td_map_def_user; curthread->td_map_def_user = entry; } } /* * 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) { vm_map_entry_t entry; vm_map_entry_t first_entry; VM_MAP_ASSERT_LOCKED(map); if (start == end) return (KERN_SUCCESS); /* * Find the start of the region, and clip it */ if (!vm_map_lookup_entry(map, start, &first_entry)) entry = first_entry->next; else { entry = first_entry; vm_map_clip_start(map, entry, start); } /* * Step through all entries in this region */ while ((entry != &map->header) && (entry->start < end)) { vm_map_entry_t next; /* * Wait for wiring or unwiring of an entry to complete. * Also wait for any system wirings to disappear on * user maps. */ if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 || (vm_map_pmap(map) != kernel_pmap && vm_map_entry_system_wired_count(entry) != 0)) { unsigned int last_timestamp; vm_offset_t saved_start; vm_map_entry_t tmp_entry; saved_start = entry->start; entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP; last_timestamp = map->timestamp; (void) vm_map_unlock_and_wait(map, 0); vm_map_lock(map); if (last_timestamp + 1 != map->timestamp) { /* * Look again for the entry because the map was * modified while it was unlocked. * Specifically, the entry may have been * clipped, merged, or deleted. */ if (!vm_map_lookup_entry(map, saved_start, &tmp_entry)) entry = tmp_entry->next; else { entry = tmp_entry; vm_map_clip_start(map, entry, saved_start); } } continue; } vm_map_clip_end(map, entry, end); next = entry->next; /* * 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); } pmap_remove(map->pmap, entry->start, entry->end); /* * Delete the entry 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); 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; vm_map_lock(map); VM_MAP_RANGE_CHECK(map, start, end); result = vm_map_delete(map, start, end); vm_map_unlock(map); 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. * * WARNING! This code does not and should not check whether the * contents of the region is accessible. For example a smaller file * might be mapped into a larger address space. * * NOTE! This code is also called by munmap(). * * The map must be locked. A read lock is sufficient. */ 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); } /* * 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_ooffset_t *fork_charge) { vm_object_t src_object; vm_map_entry_t fake_entry; vm_offset_t size; struct ucred *cred; int charged; VM_MAP_ASSERT_LOCKED(dst_map); if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP) return; if (src_entry->wired_count == 0 || (src_entry->protection & VM_PROT_WRITE) == 0) { /* * If the source entry is marked needs_copy, it is already * write-protected. */ if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 && (src_entry->protection & VM_PROT_WRITE) != 0) { pmap_protect(src_map->pmap, src_entry->start, src_entry->end, src_entry->protection & ~VM_PROT_WRITE); } /* * Make a copy of the object. */ size = src_entry->end - src_entry->start; if ((src_object = src_entry->object.vm_object) != NULL) { VM_OBJECT_WLOCK(src_object); charged = ENTRY_CHARGED(src_entry); 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_object_split(src_entry); src_object = src_entry->object.vm_object; } } vm_object_reference_locked(src_object); vm_object_clear_flag(src_object, OBJ_ONEMAPPING); if (src_entry->cred != NULL && !(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { KASSERT(src_object->cred == NULL, ("OVERCOMMIT: vm_map_copy_entry: cred %p", src_object)); src_object->cred = src_entry->cred; src_object->charge = size; } VM_OBJECT_WUNLOCK(src_object); dst_entry->object.vm_object = src_object; if (charged) { cred = curthread->td_ucred; crhold(cred); dst_entry->cred = cred; *fork_charge += size; if (!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) { crhold(cred); src_entry->cred = cred; *fork_charge += size; } } 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; if (src_entry->eflags & MAP_ENTRY_VN_WRITECNT) { /* * MAP_ENTRY_VN_WRITECNT cannot * indicate write reference from * src_entry, since the entry is * marked as needs copy. Allocate a * fake entry that is used to * decrement object->un_pager.vnp.writecount * at the appropriate time. Attach * fake_entry to the deferred list. */ fake_entry = vm_map_entry_create(dst_map); fake_entry->eflags = MAP_ENTRY_VN_WRITECNT; src_entry->eflags &= ~MAP_ENTRY_VN_WRITECNT; vm_object_reference(src_object); fake_entry->object.vm_object = src_object; fake_entry->start = src_entry->start; fake_entry->end = src_entry->end; fake_entry->next = curthread->td_map_def_user; curthread->td_map_def_user = fake_entry; } } else { dst_entry->object.vm_object = NULL; dst_entry->offset = 0; if (src_entry->cred != NULL) { dst_entry->cred = curthread->td_ucred; crhold(dst_entry->cred); *fork_charge += size; } } pmap_copy(dst_map->pmap, src_map->pmap, dst_entry->start, dst_entry->end - dst_entry->start, src_entry->start); } else { /* * We don't want to make writeable wired pages copy-on-write. * Immediately copy these pages into the new map by simulating * page faults. The new pages are pageable. */ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry, fork_charge); } } /* * vmspace_map_entry_forked: * Update the newly-forked vmspace each time a map entry is inherited * or copied. The values for vm_dsize and vm_tsize are approximate * (and mostly-obsolete ideas in the face of mmap(2) et al.) */ static void vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2, vm_map_entry_t entry) { vm_size_t entrysize; vm_offset_t newend; entrysize = entry->end - entry->start; vm2->vm_map.size += entrysize; if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) { vm2->vm_ssize += btoc(entrysize); } else if (entry->start >= (vm_offset_t)vm1->vm_daddr && entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) { newend = MIN(entry->end, (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)); vm2->vm_dsize += btoc(newend - entry->start); } else if (entry->start >= (vm_offset_t)vm1->vm_taddr && entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) { newend = MIN(entry->end, (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)); vm2->vm_tsize += btoc(newend - entry->start); } } /* * 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. * * XXX It might be worth coalescing the entries added to the new vmspace. * * The source map must not be locked. */ struct vmspace * vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge) { struct vmspace *vm2; vm_map_t new_map, old_map; vm_map_entry_t new_entry, old_entry; vm_object_t object; int locked; old_map = &vm1->vm_map; /* Copy immutable fields of vm1 to vm2. */ vm2 = vmspace_alloc(old_map->min_offset, old_map->max_offset, NULL); if (vm2 == NULL) return (NULL); vm2->vm_taddr = vm1->vm_taddr; vm2->vm_daddr = vm1->vm_daddr; vm2->vm_maxsaddr = vm1->vm_maxsaddr; vm_map_lock(old_map); if (old_map->busy) vm_map_wait_busy(old_map); new_map = &vm2->vm_map; locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */ KASSERT(locked, ("vmspace_fork: lock failed")); old_entry = old_map->header.next; while (old_entry != &old_map->header) { if (old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) 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) { object = vm_object_allocate(OBJT_DEFAULT, atop(old_entry->end - old_entry->start)); old_entry->object.vm_object = object; old_entry->offset = 0; if (old_entry->cred != NULL) { object->cred = old_entry->cred; object->charge = old_entry->end - old_entry->start; old_entry->cred = NULL; } } /* * Add the reference before calling vm_object_shadow * to insure that a shadow object is created. */ vm_object_reference(object); if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) { vm_object_shadow(&old_entry->object.vm_object, &old_entry->offset, old_entry->end - old_entry->start); old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; /* Transfer the second reference too. */ vm_object_reference( old_entry->object.vm_object); /* * As in vm_map_simplify_entry(), the * vnode lock will not be acquired in * this call to vm_object_deallocate(). */ vm_object_deallocate(object); object = old_entry->object.vm_object; } VM_OBJECT_WLOCK(object); vm_object_clear_flag(object, OBJ_ONEMAPPING); if (old_entry->cred != NULL) { KASSERT(object->cred == NULL, ("vmspace_fork both cred")); object->cred = old_entry->cred; object->charge = old_entry->end - old_entry->start; old_entry->cred = NULL; } /* * Assert the correct state of the vnode * v_writecount while the object is locked, to * not relock it later for the assertion * correctness. */ if (old_entry->eflags & MAP_ENTRY_VN_WRITECNT && object->type == OBJT_VNODE) { KASSERT(((struct vnode *)object->handle)-> v_writecount > 0, ("vmspace_fork: v_writecount %p", object)); KASSERT(object->un_pager.vnp.writemappings > 0, ("vmspace_fork: vnp.writecount %p", object)); } VM_OBJECT_WUNLOCK(object); /* * Clone the entry, referencing the shared object. */ new_entry = vm_map_entry_create(new_map); *new_entry = *old_entry; new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION); new_entry->wiring_thread = NULL; new_entry->wired_count = 0; if (new_entry->eflags & MAP_ENTRY_VN_WRITECNT) { vnode_pager_update_writecount(object, new_entry->start, new_entry->end); } /* * 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); vmspace_map_entry_forked(vm1, vm2, 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); *new_entry = *old_entry; /* * Copied entry is COW over the old object. */ new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_VN_WRITECNT); new_entry->wiring_thread = NULL; new_entry->wired_count = 0; new_entry->object.vm_object = NULL; new_entry->cred = NULL; vm_map_entry_link(new_map, new_map->header.prev, new_entry); vmspace_map_entry_forked(vm1, vm2, new_entry); vm_map_copy_entry(old_map, new_map, old_entry, new_entry, fork_charge); break; } old_entry = old_entry->next; } /* * Use inlined vm_map_unlock() to postpone handling the deferred * map entries, which cannot be done until both old_map and * new_map locks are released. */ sx_xunlock(&old_map->lock); sx_xunlock(&new_map->lock); vm_map_process_deferred(); return (vm2); } int vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_prot_t prot, vm_prot_t max, int cow) { vm_size_t growsize, init_ssize; rlim_t lmemlim, vmemlim; int rv; growsize = sgrowsiz; init_ssize = (max_ssize < growsize) ? max_ssize : growsize; vm_map_lock(map); PROC_LOCK(curproc); lmemlim = lim_cur(curproc, RLIMIT_MEMLOCK); vmemlim = lim_cur(curproc, RLIMIT_VMEM); PROC_UNLOCK(curproc); if (!old_mlock && map->flags & MAP_WIREFUTURE) { if (ptoa(pmap_wired_count(map->pmap)) + init_ssize > lmemlim) { rv = KERN_NO_SPACE; goto out; } } /* If we would blow our VMEM resource limit, no go */ if (map->size + init_ssize > vmemlim) { rv = KERN_NO_SPACE; goto out; } rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot, max, cow); out: vm_map_unlock(map); return (rv); } static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow) { vm_map_entry_t new_entry, prev_entry; vm_offset_t bot, top; vm_size_t init_ssize; int orient, rv; /* * The stack orientation is piggybacked with the cow argument. * Extract it into orient and mask the cow argument so that we * don't pass it around further. * NOTE: We explicitly allow bi-directional stacks. */ orient = cow & (MAP_STACK_GROWS_DOWN|MAP_STACK_GROWS_UP); KASSERT(orient != 0, ("No stack grow direction")); if (addrbos < vm_map_min(map) || addrbos > vm_map_max(map) || addrbos + max_ssize < addrbos) return (KERN_NO_SPACE); init_ssize = (max_ssize < growsize) ? max_ssize : growsize; /* If addr is already mapped, no go */ if (vm_map_lookup_entry(map, addrbos, &prev_entry)) return (KERN_NO_SPACE); /* * 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)) return (KERN_NO_SPACE); /* * We initially map a stack of only init_ssize. We will grow as * needed later. Depending on the orientation of the stack (i.e. * the grow direction) we either map at the top of the range, the * bottom of the range or in the middle. * * 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. */ if (orient == MAP_STACK_GROWS_DOWN) bot = addrbos + max_ssize - init_ssize; else if (orient == MAP_STACK_GROWS_UP) bot = addrbos; else bot = round_page(addrbos + max_ssize/2 - init_ssize/2); top = bot + init_ssize; rv = vm_map_insert(map, NULL, 0, bot, top, 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, bot); new_entry = prev_entry->next; if (new_entry->end != top || new_entry->start != bot) panic("Bad entry start/end for new stack entry"); new_entry->avail_ssize = max_ssize - init_ssize; if (orient & MAP_STACK_GROWS_DOWN) new_entry->eflags |= MAP_ENTRY_GROWS_DOWN; if (orient & MAP_STACK_GROWS_UP) new_entry->eflags |= MAP_ENTRY_GROWS_UP; } return (rv); } static int stack_guard_page = 0; TUNABLE_INT("security.bsd.stack_guard_page", &stack_guard_page); SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RW, &stack_guard_page, 0, "Insert stack guard page ahead of the growable segments."); /* 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 next_entry, prev_entry; vm_map_entry_t new_entry, stack_entry; struct vmspace *vm = p->p_vmspace; vm_map_t map = &vm->vm_map; vm_offset_t end; vm_size_t growsize; size_t grow_amount, max_grow; rlim_t lmemlim, stacklim, vmemlim; int is_procstack, rv; struct ucred *cred; #ifdef notyet uint64_t limit; #endif #ifdef RACCT int error; #endif Retry: PROC_LOCK(p); lmemlim = lim_cur(p, RLIMIT_MEMLOCK); stacklim = lim_cur(p, RLIMIT_STACK); vmemlim = lim_cur(p, RLIMIT_VMEM); PROC_UNLOCK(p); vm_map_lock_read(map); /* If addr is already in the entry range, no need to grow.*/ if (vm_map_lookup_entry(map, addr, &prev_entry)) { vm_map_unlock_read(map); return (KERN_SUCCESS); } next_entry = prev_entry->next; if (!(prev_entry->eflags & MAP_ENTRY_GROWS_UP)) { /* * This entry does not grow upwards. Since the address lies * beyond this entry, the next entry (if one exists) has to * be a downward growable entry. The entry list header is * never a growable entry, so it suffices to check the flags. */ if (!(next_entry->eflags & MAP_ENTRY_GROWS_DOWN)) { vm_map_unlock_read(map); return (KERN_SUCCESS); } stack_entry = next_entry; } else { /* * This entry grows upward. If the next entry does not at * least grow downwards, this is the entry we need to grow. * otherwise we have two possible choices and we have to * select one. */ if (next_entry->eflags & MAP_ENTRY_GROWS_DOWN) { /* * We have two choices; grow the entry closest to * the address to minimize the amount of growth. */ if (addr - prev_entry->end <= next_entry->start - addr) stack_entry = prev_entry; else stack_entry = next_entry; } else stack_entry = prev_entry; } if (stack_entry == next_entry) { KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_DOWN, ("foo")); KASSERT(addr < stack_entry->start, ("foo")); end = (prev_entry != &map->header) ? prev_entry->end : stack_entry->start - stack_entry->avail_ssize; grow_amount = roundup(stack_entry->start - addr, PAGE_SIZE); max_grow = stack_entry->start - end; } else { KASSERT(stack_entry->eflags & MAP_ENTRY_GROWS_UP, ("foo")); KASSERT(addr >= stack_entry->end, ("foo")); end = (next_entry != &map->header) ? next_entry->start : stack_entry->end + stack_entry->avail_ssize; grow_amount = roundup(addr + 1 - stack_entry->end, PAGE_SIZE); max_grow = end - stack_entry->end; } if (grow_amount > stack_entry->avail_ssize) { vm_map_unlock_read(map); return (KERN_NO_SPACE); } /* * 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_guard_page ? PAGE_SIZE : 0) > max_grow) { if (vm_map_lock_upgrade(map)) goto Retry; stack_entry->avail_ssize = max_grow; vm_map_unlock(map); return (KERN_NO_SPACE); } is_procstack = (addr >= (vm_offset_t)vm->vm_maxsaddr && addr < (vm_offset_t)p->p_sysent->sv_usrstack) ? 1 : 0; /* * If this is the main process stack, see if we're over the stack * limit. */ if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { vm_map_unlock_read(map); return (KERN_NO_SPACE); } #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (is_procstack && racct_set(p, RACCT_STACK, ctob(vm->vm_ssize) + grow_amount)) { PROC_UNLOCK(p); vm_map_unlock_read(map); return (KERN_NO_SPACE); } PROC_UNLOCK(p); } #endif /* Round up the grow amount modulo sgrowsiz */ growsize = sgrowsiz; grow_amount = roundup(grow_amount, growsize); if (grow_amount > stack_entry->avail_ssize) grow_amount = stack_entry->avail_ssize; if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) { grow_amount = trunc_page((vm_size_t)stacklim) - ctob(vm->vm_ssize); } #ifdef notyet PROC_LOCK(p); limit = racct_get_available(p, RACCT_STACK); PROC_UNLOCK(p); if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit)) grow_amount = limit - ctob(vm->vm_ssize); #endif if (!old_mlock && map->flags & MAP_WIREFUTURE) { if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) { vm_map_unlock_read(map); rv = KERN_NO_SPACE; goto out; } #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (racct_set(p, RACCT_MEMLOCK, ptoa(pmap_wired_count(map->pmap)) + grow_amount)) { PROC_UNLOCK(p); vm_map_unlock_read(map); rv = KERN_NO_SPACE; goto out; } PROC_UNLOCK(p); } #endif } /* If we would blow our VMEM resource limit, no go */ if (map->size + grow_amount > vmemlim) { vm_map_unlock_read(map); rv = KERN_NO_SPACE; goto out; } #ifdef RACCT if (racct_enable) { PROC_LOCK(p); if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) { PROC_UNLOCK(p); vm_map_unlock_read(map); rv = KERN_NO_SPACE; goto out; } PROC_UNLOCK(p); } #endif if (vm_map_lock_upgrade(map)) goto Retry; if (stack_entry == next_entry) { /* * Growing downward. */ /* 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->avail_ssize = max_grow; addr = end; if (stack_guard_page) addr += PAGE_SIZE; } rv = vm_map_insert(map, NULL, 0, addr, stack_entry->start, next_entry->protection, next_entry->max_protection, 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); new_entry = prev_entry->next; KASSERT(new_entry == stack_entry->prev, ("foo")); KASSERT(new_entry->end == stack_entry->start, ("foo")); KASSERT(new_entry->start == addr, ("foo")); grow_amount = new_entry->end - new_entry->start; new_entry->avail_ssize = stack_entry->avail_ssize - grow_amount; stack_entry->eflags &= ~MAP_ENTRY_GROWS_DOWN; new_entry->eflags |= MAP_ENTRY_GROWS_DOWN; } } else { /* * Growing upward. */ addr = stack_entry->end + grow_amount; /* * If this puts us into the next entry, cut back our growth * to the available space. Also, see the note above. */ if (addr > end) { stack_entry->avail_ssize = end - stack_entry->end; addr = end; if (stack_guard_page) addr -= PAGE_SIZE; } grow_amount = addr - stack_entry->end; cred = stack_entry->cred; if (cred == NULL && stack_entry->object.vm_object != NULL) cred = stack_entry->object.vm_object->cred; if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred)) rv = KERN_NO_SPACE; /* Grow the underlying object if applicable. */ else if (stack_entry->object.vm_object == NULL || vm_object_coalesce(stack_entry->object.vm_object, stack_entry->offset, (vm_size_t)(stack_entry->end - stack_entry->start), (vm_size_t)grow_amount, cred != NULL)) { map->size += (addr - stack_entry->end); /* Update the current entry. */ stack_entry->end = addr; stack_entry->avail_ssize -= grow_amount; vm_map_entry_resize_free(map, stack_entry); rv = KERN_SUCCESS; if (next_entry != &map->header) vm_map_clip_start(map, next_entry, addr); } else rv = KERN_FAILURE; } if (rv == KERN_SUCCESS && is_procstack) vm->vm_ssize += btoc(grow_amount); vm_map_unlock(map); /* * Heed the MAP_WIREFUTURE flag if it was set for this process. */ if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE)) { vm_map_wire(map, (stack_entry == next_entry) ? addr : addr - grow_amount, (stack_entry == next_entry) ? stack_entry->start : addr, (p->p_flag & P_SYSTEM) ? VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES : VM_MAP_WIRE_USER|VM_MAP_WIRE_NOHOLES); } out: #ifdef RACCT if (racct_enable && rv != KERN_SUCCESS) { PROC_LOCK(p); error = racct_set(p, RACCT_VMEM, map->size); KASSERT(error == 0, ("decreasing RACCT_VMEM failed")); if (!old_mlock) { error = racct_set(p, RACCT_MEMLOCK, ptoa(pmap_wired_count(map->pmap))); KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed")); } error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize)); KASSERT(error == 0, ("decreasing RACCT_STACK failed")); PROC_UNLOCK(p); } #endif 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. */ int vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0, ("vmspace_exec recursed")); newvmspace = vmspace_alloc(minuser, maxuser, NULL); if (newvmspace == NULL) return (ENOMEM); newvmspace->vm_swrss = oldvmspace->vm_swrss; /* * This code is written like this for prototype purposes. The * goal is to avoid running down the vmspace here, but let the * other process's that are still using the vmspace to finally * run it down. Even though there is little or no chance of blocking * here, it is a good idea to keep this form for future mods. */ PROC_VMSPACE_LOCK(p); p->p_vmspace = newvmspace; PROC_VMSPACE_UNLOCK(p); if (p == curthread->td_proc) pmap_activate(curthread); curthread->td_pflags |= TDP_EXECVMSPC; return (0); } /* * Unshare the specified VM space for forcing COW. This * is called by rfork, for the (RFMEM|RFPROC) == 0 case. */ int vmspace_unshare(struct proc *p) { struct vmspace *oldvmspace = p->p_vmspace; struct vmspace *newvmspace; vm_ooffset_t fork_charge; if (oldvmspace->vm_refcnt == 1) return (0); fork_charge = 0; newvmspace = vmspace_fork(oldvmspace, &fork_charge); if (newvmspace == NULL) return (ENOMEM); if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) { vmspace_free(newvmspace); return (ENOMEM); } PROC_VMSPACE_LOCK(p); p->p_vmspace = newvmspace; PROC_VMSPACE_UNLOCK(p); if (p == curthread->td_proc) pmap_activate(curthread); vmspace_free(oldvmspace); return (0); } /* * 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; vm_object_t eobject; vm_size_t size; struct ucred *cred; RetryLookup:; vm_map_lock_read(map); /* * Lookup the faulting address. */ if (!vm_map_lookup_entry(map, vaddr, out_entry)) { vm_map_unlock_read(map); return (KERN_INVALID_ADDRESS); } entry = *out_entry; /* * Handle submaps. */ if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { vm_map_t old_map = map; *var_map = map = entry->object.sub_map; vm_map_unlock_read(old_map); goto RetryLookup; } /* * Check whether this task is allowed to have this page. */ prot = entry->protection; fault_type &= (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) { vm_map_unlock_read(map); return (KERN_PROTECTION_FAILURE); } KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags & (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) != (MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY), ("entry %p flags %x", entry, entry->eflags)); if ((fault_typea & VM_PROT_COPY) != 0 && (entry->max_protection & VM_PROT_WRITE) == 0 && (entry->eflags & MAP_ENTRY_COW) == 0) { vm_map_unlock_read(map); return (KERN_PROTECTION_FAILURE); } /* * If this page is not pageable, we have to get it for all possible * accesses. */ *wired = (entry->wired_count != 0); if (*wired) fault_type = entry->protection; size = entry->end - entry->start; /* * 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) != 0 || (fault_typea & VM_PROT_COPY) != 0) { /* * 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 (vm_map_lock_upgrade(map)) goto RetryLookup; if (entry->cred == NULL) { /* * The debugger owner is charged for * the memory. */ cred = curthread->td_ucred; crhold(cred); if (!swap_reserve_by_cred(size, cred)) { crfree(cred); vm_map_unlock(map); return (KERN_RESOURCE_SHORTAGE); } entry->cred = cred; } vm_object_shadow(&entry->object.vm_object, &entry->offset, size); entry->eflags &= ~MAP_ENTRY_NEEDS_COPY; eobject = entry->object.vm_object; if (eobject->cred != NULL) { /* * The object was not shadowed. */ swap_release_by_cred(size, entry->cred); crfree(entry->cred); entry->cred = NULL; } else if (entry->cred != NULL) { VM_OBJECT_WLOCK(eobject); eobject->cred = entry->cred; eobject->charge = size; VM_OBJECT_WUNLOCK(eobject); entry->cred = NULL; } vm_map_lock_downgrade(map); } 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 (vm_map_lock_upgrade(map)) goto RetryLookup; entry->object.vm_object = vm_object_allocate(OBJT_DEFAULT, atop(size)); entry->offset = 0; if (entry->cred != NULL) { VM_OBJECT_WLOCK(entry->object.vm_object); entry->object.vm_object->cred = entry->cred; entry->object.vm_object->charge = size; VM_OBJECT_WUNLOCK(entry->object.vm_object); entry->cred = NULL; } vm_map_lock_downgrade(map); } /* * 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; *out_prot = prot; return (KERN_SUCCESS); } /* * vm_map_lookup_locked: * * Lookup the faulting address. A version of vm_map_lookup that returns * KERN_FAILURE instead of blocking on map lock or memory allocation. */ int vm_map_lookup_locked(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; /* * Lookup the faulting address. */ if (!vm_map_lookup_entry(map, vaddr, out_entry)) return (KERN_INVALID_ADDRESS); entry = *out_entry; /* * Fail if the entry refers to a submap. */ if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) return (KERN_FAILURE); /* * Check whether this task is allowed to have this page. */ prot = entry->protection; fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE; if ((fault_type & prot) != fault_type) return (KERN_PROTECTION_FAILURE); /* * If this page is not pageable, we have to get it for all possible * accesses. */ *wired = (entry->wired_count != 0); if (*wired) fault_type = entry->protection; if (entry->eflags & MAP_ENTRY_NEEDS_COPY) { /* * Fail if the entry was copy-on-write for a write fault. */ if (fault_type & VM_PROT_WRITE) return (KERN_FAILURE); /* * We're attempting to read a copy-on-write page -- * don't allow writes. */ prot &= ~VM_PROT_WRITE; } /* * Fail if an object should be created. */ if (entry->object.vm_object == NULL && !map->system_map) return (KERN_FAILURE); /* * 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; *out_prot = prot; return (KERN_SUCCESS); } /* * 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) { /* * Unlock the main-level map */ vm_map_unlock_read(map); } #include "opt_ddb.h" #ifdef DDB #include #include static void vm_map_print(vm_map_t map) { 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); 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); { 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->eflags & MAP_ENTRY_IS_SUB_MAP) { db_printf(", share=%p, offset=0x%jx\n", (void *)entry->object.sub_map, (uintmax_t)entry->offset); if ((entry->prev == &map->header) || (entry->prev->object.sub_map != entry->object.sub_map)) { db_indent += 2; vm_map_print((vm_map_t)entry->object.sub_map); db_indent -= 2; } } else { if (entry->cred != NULL) db_printf(", ruid %d", entry->cred->cr_ruid); db_printf(", object=%p, offset=0x%jx", (void *)entry->object.vm_object, (uintmax_t)entry->offset); if (entry->object.vm_object && entry->object.vm_object->cred) db_printf(", obj ruid %d charge %jx", entry->object.vm_object->cred->cr_ruid, (uintmax_t)entry->object.vm_object->charge); if (entry->eflags & MAP_ENTRY_COW) db_printf(", copy (%s)", (entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done"); db_printf("\n"); 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, 0, 0, (char *)0); db_indent -= 2; } } } db_indent -= 2; } DB_SHOW_COMMAND(map, map) { if (!have_addr) { db_printf("usage: show map \n"); return; } vm_map_print((vm_map_t)addr); } 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((vm_map_t)&p->p_vmspace->vm_map); } #endif /* DDB */