]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/vm/vm_map_store_rb.c
xnu-7195.50.7.100.1.tar.gz
[apple/xnu.git] / osfmk / vm / vm_map_store_rb.c
index 1643d1dd92ab69f3672a7a29f3e03c1de595aa30..bcecbea57ee45acc43dd53b8305572310264e0f6 100644 (file)
@@ -2,7 +2,7 @@
  * Copyright (c) 2009 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
+#include <kern/backtrace.h>
 #include <vm/vm_map_store_rb.h>
 
 RB_GENERATE(rb_head, vm_map_store, entry, rb_node_compare);
 
-#define VME_FOR_STORE( store)  \
+#define VME_FOR_STORE( store)   \
        (vm_map_entry_t)(((unsigned long)store) - ((unsigned long)sizeof(struct vm_map_links)))
 
 void
@@ -39,45 +40,53 @@ vm_map_store_init_rb( struct vm_map_header* hdr )
        RB_INIT(&(hdr->rb_head_store));
 }
 
-int rb_node_compare(struct vm_map_store *node, struct vm_map_store *parent)
+int
+rb_node_compare(struct vm_map_store *node, struct vm_map_store *parent)
 {
        vm_map_entry_t vme_c;
        vm_map_entry_t vme_p;
 
        vme_c = VME_FOR_STORE(node);
        vme_p =  VME_FOR_STORE(parent);
-       if (vme_c->vme_start < vme_p->vme_start)
+       if (vme_c->vme_start < vme_p->vme_start) {
                return -1;
-       if (vme_c->vme_start >= vme_p->vme_end)
+       }
+       if (vme_c->vme_start >= vme_p->vme_end) {
                return 1;
+       }
        return 0;
 }
 
-void vm_map_store_walk_rb( vm_map_t map, vm_map_entry_t *wrong_vme, vm_map_entry_t *vm_entry)
+__dead2
+void
+vm_map_store_walk_rb(vm_map_t map, vm_map_entry_t *wrong_vme, vm_map_entry_t *vm_entry)
 {
-       struct vm_map_header hdr = map->hdr;
-       struct vm_map_store *rb_entry = RB_ROOT(&(hdr.rb_head_store));
-       vm_map_entry_t cur = *vm_entry;
+       struct vm_map_header *hdr = &map->hdr;
+       struct vm_map_store  *rb_entry = RB_ROOT(&hdr->rb_head_store);
+       vm_map_entry_t       cur = *vm_entry;
 
-       rb_entry = RB_FIND( rb_head, &(hdr.rb_head_store), &(cur->store));      
-       if(rb_entry == NULL)
+       rb_entry = RB_FIND(rb_head, &hdr->rb_head_store, &(cur->store));
+       if (rb_entry == NULL) {
                panic("NO SUCH ENTRY %p. Gave back %p", *vm_entry, *wrong_vme);
-       else
-               panic("Cur: %p, L: %p, R: %p",  VME_FOR_STORE(rb_entry),  VME_FOR_STORE(RB_LEFT(rb_entry,entry)),  VME_FOR_STORE(RB_RIGHT(rb_entry,entry)));
+       } else {
+               panic("Cur: %p, L: %p, R: %p", VME_FOR_STORE(rb_entry), VME_FOR_STORE(RB_LEFT(rb_entry, entry)), VME_FOR_STORE(RB_RIGHT(rb_entry, entry)));
+       }
 }
 
 
-boolean_t vm_map_store_lookup_entry_rb( vm_map_t map, vm_map_offset_t address, vm_map_entry_t *vm_entry)
+boolean_t
+vm_map_store_lookup_entry_rb(vm_map_t map, vm_map_offset_t address, vm_map_entry_t *vm_entry)
 {
-       struct vm_map_header hdr = map->hdr;
-       struct vm_map_store *rb_entry = RB_ROOT(&(hdr.rb_head_store));
-       vm_map_entry_t cur = vm_map_to_entry(map);
-       vm_map_entry_t prev = VM_MAP_ENTRY_NULL;
+       struct vm_map_header *hdr = &map->hdr;
+       struct vm_map_store  *rb_entry = RB_ROOT(&hdr->rb_head_store);
+       vm_map_entry_t       cur = vm_map_to_entry(map);
+       vm_map_entry_t       prev = VM_MAP_ENTRY_NULL;
 
        while (rb_entry != (struct vm_map_store*)NULL) {
-                       cur =  VME_FOR_STORE(rb_entry);
-               if(cur == VM_MAP_ENTRY_NULL)
+               cur =  VME_FOR_STORE(rb_entry);
+               if (cur == VM_MAP_ENTRY_NULL) {
                        panic("no entry");
+               }
                if (address >= cur->vme_start) {
                        if (address < cur->vme_end) {
                                *vm_entry = cur;
@@ -89,61 +98,37 @@ boolean_t vm_map_store_lookup_entry_rb( vm_map_t map, vm_map_offset_t address, v
                        rb_entry = RB_LEFT(rb_entry, entry);
                }
        }
-       if( prev == VM_MAP_ENTRY_NULL){
+       if (prev == VM_MAP_ENTRY_NULL) {
                prev = vm_map_to_entry(map);
        }
        *vm_entry = prev;
        return FALSE;
 }
 
-void   vm_map_store_entry_link_rb( struct vm_map_header *mapHdr, __unused vm_map_entry_t after_where, vm_map_entry_t entry)
+void
+vm_map_store_entry_link_rb( struct vm_map_header *mapHdr, __unused vm_map_entry_t after_where, vm_map_entry_t entry)
 {
        struct rb_head *rbh = &(mapHdr->rb_head_store);
        struct vm_map_store *store = &(entry->store);
        struct vm_map_store *tmp_store;
-       if((tmp_store = RB_INSERT( rb_head, rbh, store )) != NULL) {
+       if ((tmp_store = RB_INSERT( rb_head, rbh, store )) != NULL) {
                panic("VMSEL: INSERT FAILED: 0x%lx, 0x%lx, 0x%lx, 0x%lx", (uintptr_t)entry->vme_start, (uintptr_t)entry->vme_end,
-                               (uintptr_t)(VME_FOR_STORE(tmp_store))->vme_start,  (uintptr_t)(VME_FOR_STORE(tmp_store))->vme_end);
+                   (uintptr_t)(VME_FOR_STORE(tmp_store))->vme_start, (uintptr_t)(VME_FOR_STORE(tmp_store))->vme_end);
        }
 }
 
-void   vm_map_store_entry_unlink_rb( struct vm_map_header *mapHdr, vm_map_entry_t entry)
+void
+vm_map_store_entry_unlink_rb( struct vm_map_header *mapHdr, vm_map_entry_t entry)
 {
        struct rb_head *rbh = &(mapHdr->rb_head_store);
        struct vm_map_store *rb_entry;
        struct vm_map_store *store = &(entry->store);
-       
-       rb_entry = RB_FIND( rb_head, rbh, store);       
-       if(rb_entry == NULL)
-               panic("NO ENTRY TO DELETE");
-       RB_REMOVE( rb_head, rbh, store );
-}
 
-void   vm_map_store_copy_insert_rb( vm_map_t map, __unused vm_map_entry_t after_where, vm_map_copy_t copy)
-{
-       struct vm_map_header *mapHdr = &(map->hdr);
-       struct rb_head *rbh = &(mapHdr->rb_head_store);
-       struct vm_map_store *store;
-       vm_map_entry_t entry = vm_map_copy_first_entry(copy);
-       int inserted=0, nentries = copy->cpy_hdr.nentries;
-               
-       while (entry != vm_map_copy_to_entry(copy) && nentries > 0) {           
-               vm_map_entry_t prev = entry;
-               store = &(entry->store);
-               if( RB_INSERT( rb_head, rbh, store ) != NULL){
-                       panic("VMSCIR1: INSERT FAILED: %d: %p, %p, %p, 0x%lx, 0x%lx, 0x%lx, 0x%lx, 0x%lx, 0x%lx",inserted, prev, entry, vm_map_copy_to_entry(copy), 
-                                       (uintptr_t)prev->vme_start,  (uintptr_t)prev->vme_end,  (uintptr_t)entry->vme_start,  (uintptr_t)entry->vme_end,  
-                                        (uintptr_t)(VME_FOR_STORE(rbh->rbh_root))->vme_start,  (uintptr_t)(VME_FOR_STORE(rbh->rbh_root))->vme_end);
-               } else {
-#if MAP_ENTRY_INSERTION_DEBUG
-                       fastbacktrace(&entry->vme_insertion_bt[0],
-                                     (sizeof (entry->vme_insertion_bt) / sizeof (uintptr_t)));
-#endif
-                       entry = entry->vme_next;
-                       inserted++;
-                       nentries--;
-               }
+       rb_entry = RB_FIND( rb_head, rbh, store);
+       if (rb_entry == NULL) {
+               panic("NO ENTRY TO DELETE");
        }
+       RB_REMOVE( rb_head, rbh, store );
 }
 
 void
@@ -152,9 +137,9 @@ vm_map_store_copy_reset_rb( vm_map_copy_t copy, vm_map_entry_t entry, int nentri
        struct vm_map_header *mapHdr = &(copy->cpy_hdr);
        struct rb_head *rbh = &(mapHdr->rb_head_store);
        struct vm_map_store *store;
-       int deleted=0;
-               
-       while (entry != vm_map_copy_to_entry(copy) && nentries > 0) {           
+       int deleted = 0;
+
+       while (entry != vm_map_copy_to_entry(copy) && nentries > 0) {
                store = &(entry->store);
                RB_REMOVE( rb_head, rbh, store );
                entry = entry->vme_next;
@@ -163,8 +148,546 @@ vm_map_store_copy_reset_rb( vm_map_copy_t copy, vm_map_entry_t entry, int nentri
        }
 }
 
-void   update_first_free_rb( __unused vm_map_t map, __unused vm_map_entry_t entry)
+extern zone_t   vm_map_holes_zone;      /* zone for vm map holes (vm_map_links) structures */
+
+void
+vm_map_combine_hole(vm_map_t map, vm_map_entry_t hole_entry);
+void
+vm_map_combine_hole(__unused vm_map_t map, vm_map_entry_t hole_entry)
+{
+       vm_map_entry_t middle_hole_entry, last_hole_entry;
+
+       hole_entry->vme_end = hole_entry->vme_next->vme_end;
+
+       middle_hole_entry = hole_entry->vme_next;
+       last_hole_entry = middle_hole_entry->vme_next;
+
+       assert(last_hole_entry->vme_prev == middle_hole_entry);
+       assert(middle_hole_entry->vme_end != last_hole_entry->vme_start);
+
+       last_hole_entry->vme_prev = hole_entry;
+       hole_entry->vme_next = last_hole_entry;
+
+       middle_hole_entry->vme_prev = NULL;
+       middle_hole_entry->vme_next = NULL;
+
+       zfree(vm_map_holes_zone, middle_hole_entry);
+
+       assert(hole_entry->vme_start < hole_entry->vme_end);
+       assert(last_hole_entry->vme_start < last_hole_entry->vme_end);
+}
+
+
+void
+vm_map_delete_hole(vm_map_t map, vm_map_entry_t hole_entry);
+void
+vm_map_delete_hole(vm_map_t map, vm_map_entry_t hole_entry)
+{
+       if (hole_entry == CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+               if (hole_entry->vme_next == CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                       map->holes_list = NULL;
+                       SAVE_HINT_HOLE_WRITE(map, NULL);
+               } else {
+                       vm_map_entry_t l_next, l_prev;
+
+                       l_next = (vm_map_entry_t) map->holes_list->next;
+                       l_prev = (vm_map_entry_t) map->holes_list->prev;
+                       map->holes_list = (struct vm_map_links*) l_next;
+
+                       l_next->vme_prev = l_prev;
+                       l_prev->vme_next = l_next;
+
+                       SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) l_next);
+               }
+       } else {
+               SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) hole_entry->vme_prev);
+
+               hole_entry->vme_prev->vme_next = hole_entry->vme_next;
+               hole_entry->vme_next->vme_prev = hole_entry->vme_prev;
+       }
+
+       hole_entry->vme_next = NULL;
+       hole_entry->vme_prev = NULL;
+       zfree(vm_map_holes_zone, hole_entry);
+}
+
+
+/*
+ * For Debugging.
+ */
+
+#if DEBUG
+extern int vm_check_map_sanity;
+
+static void
+check_map_sanity(vm_map_t map, vm_map_entry_t old_hole_entry)
+{
+       vm_map_entry_t  hole_entry, next_hole_entry;
+       vm_map_entry_t  map_entry, next_map_entry;
+
+       if (map->holes_list == NULL) {
+               return;
+       }
+
+       hole_entry = CAST_DOWN(vm_map_entry_t, map->holes_list);
+       next_hole_entry = hole_entry->vme_next;
+
+       map_entry = vm_map_first_entry(map);
+       next_map_entry = map_entry->vme_next;
+
+       while (map_entry->vme_start > hole_entry->vme_start) {
+               hole_entry = next_hole_entry;
+               next_hole_entry = hole_entry->vme_next;
+
+               if (hole_entry == CAST_DOWN(vm_map_entry_t, map->holes_list)) {
+                       break;
+               }
+       }
+
+       while (map_entry != vm_map_to_entry(map)) {
+               if (map_entry->vme_start >= map->max_offset) {
+                       break;
+               }
+
+               if (map_entry->vme_end != map_entry->vme_next->vme_start) {
+                       if (map_entry->vme_next == vm_map_to_entry(map)) {
+                               break;
+                       }
+
+                       if (hole_entry->vme_start != map_entry->vme_end) {
+                               panic("hole_entry not aligned %p(0x%llx), %p (0x%llx), %p", hole_entry, (unsigned long long)hole_entry->vme_start, map_entry->vme_next, (unsigned long long)map_entry->vme_end, old_hole_entry);
+                               assert(hole_entry->vme_start == map_entry->vme_end);
+                       }
+
+                       if (hole_entry->vme_end != map_entry->vme_next->vme_start) {
+                               panic("hole_entry not next aligned %p(0x%llx), %p (0x%llx), %p", hole_entry, (unsigned long long)hole_entry->vme_end, map_entry->vme_next, (unsigned long long)map_entry->vme_next->vme_start, old_hole_entry);
+                               assert(hole_entry->vme_end == map_entry->vme_next->vme_start);
+                       }
+
+                       hole_entry = next_hole_entry;
+                       next_hole_entry = hole_entry->vme_next;
+
+                       if (hole_entry == CAST_DOWN(vm_map_entry_t, map->holes_list)) {
+                               break;
+                       }
+               }
+
+               map_entry = map_entry->vme_next;
+       }
+}
+
+/*
+ * For debugging.
+ */
+static void
+copy_hole_info(vm_map_entry_t hole_entry, vm_map_entry_t old_hole_entry)
 {
-       return ;
+       old_hole_entry->vme_prev = hole_entry->vme_prev;
+       old_hole_entry->vme_next = hole_entry->vme_next;
+       old_hole_entry->vme_start = hole_entry->vme_start;
+       old_hole_entry->vme_end = hole_entry->vme_end;
 }
+#endif /* DEBUG */
+
+void
+update_holes_on_entry_deletion(vm_map_t map, vm_map_entry_t old_entry);
+void
+update_holes_on_entry_deletion(vm_map_t map, vm_map_entry_t old_entry)
+{
+       /*
+        * Dealing with the deletion of an older entry.
+        */
+
+       vm_map_entry_t          hole_entry, next_hole_entry;
+#if DEBUG
+       struct vm_map_entry     old_hole_entry;
+#endif /* DEBUG */
+       boolean_t               create_new_hole = TRUE;
 
+       hole_entry = CAST_TO_VM_MAP_ENTRY(map->hole_hint);
+
+       if (hole_entry) {
+               if (hole_entry->vme_end == old_entry->vme_start) {
+                       /*
+                        * Found a hole right after above our entry.
+                        * Hit.
+                        */
+               } else if (hole_entry->vme_start == old_entry->vme_end) {
+                       if (hole_entry != CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                               /*
+                                * Found a hole right after below our entry but
+                                * make sure we don't erroneously extend backwards.
+                                *
+                                * Hit.
+                                */
+
+                               hole_entry = hole_entry->vme_prev;
+                       }
+               } else if (hole_entry->vme_start > old_entry->vme_end) {
+                       /*
+                        * Useless hint. Start from the top.
+                        */
+
+                       hole_entry = CAST_TO_VM_MAP_ENTRY(map->holes_list);
+               }
+
+               if (hole_entry != CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                       if (hole_entry->vme_start > old_entry->vme_start) {
+                               panic("Hole hint failed: Hole entry start: 0x%llx, entry start: 0x%llx, map hole start: 0x%llx, map hint start: 0x%llx\n",
+                                   (unsigned long long)hole_entry->vme_start,
+                                   (unsigned long long)old_entry->vme_start,
+                                   (unsigned long long)map->holes_list->start,
+                                   (unsigned long long)map->hole_hint->start);
+                       }
+                       if (hole_entry->vme_end > old_entry->vme_start) {
+                               panic("Hole hint failed: Hole entry end: 0x%llx, entry start: 0x%llx, map hole start: 0x%llx, map hint start: 0x%llx\n",
+                                   (unsigned long long)hole_entry->vme_end,
+                                   (unsigned long long)old_entry->vme_start,
+                                   (unsigned long long)map->holes_list->start,
+                                   (unsigned long long)map->hole_hint->start);
+                       }
+               }
+
+               while (1) {
+                       next_hole_entry = hole_entry->vme_next;
+
+                       /*
+                        * Hole is right above the entry.
+                        */
+                       if (hole_entry->vme_end == old_entry->vme_start) {
+#if DEBUG
+                               copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                               /*
+                                * Is there another hole right below the entry?
+                                * Can we combine holes?
+                                */
+
+                               if (old_entry->vme_end == hole_entry->vme_next->vme_start) {
+                                       vm_map_combine_hole(map, hole_entry);
+                               } else {
+                                       hole_entry->vme_end = old_entry->vme_end;
+                               }
+                               create_new_hole = FALSE;
+#if DEBUG
+                               if (vm_check_map_sanity) {
+                                       check_map_sanity(map, &old_hole_entry);
+                               }
+#endif /* DEBUG */
+                               break;
+                       }
+
+                       /*
+                        * Hole is right below the entry.
+                        */
+                       if (hole_entry->vme_start == old_entry->vme_end) {
+#if DEBUG
+                               copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                               hole_entry->vme_start = old_entry->vme_start;
+                               create_new_hole = FALSE;
+
+#if DEBUG
+                               if (vm_check_map_sanity) {
+                                       check_map_sanity(map, &old_hole_entry);
+                               }
+#endif /* DEBUG */
+                               break;
+                       }
+
+                       /*
+                        * Hole is beyond our entry. Let's go back to the last hole
+                        * before our entry so we have the right place to link up the
+                        * new hole that will be needed.
+                        */
+                       if (hole_entry->vme_start > old_entry->vme_end) {
+#if DEBUG
+                               copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                               if (hole_entry != CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                                       assert(hole_entry->vme_start != old_entry->vme_start);
+                                       hole_entry = hole_entry->vme_prev;
+                               }
+                               break;
+                       }
+
+                       hole_entry = next_hole_entry;
+
+                       if (hole_entry == CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                               hole_entry = hole_entry->vme_prev;
+                               break;
+                       }
+               }
+       }
+
+       if (create_new_hole) {
+               struct vm_map_links     *new_hole_entry = NULL;
+               vm_map_entry_t          l_next, l_prev;
+
+               new_hole_entry = zalloc(vm_map_holes_zone);
+
+               /*
+                * First hole in the map?
+                * OR
+                * A hole that is located above the current first hole in the map?
+                */
+               if (map->holes_list == NULL || (hole_entry == CAST_TO_VM_MAP_ENTRY(map->holes_list) && hole_entry->vme_start > old_entry->vme_start)) {
+                       if (map->holes_list == NULL) {
+                               map->holes_list = new_hole_entry;
+                               new_hole_entry->prev = new_hole_entry->next = CAST_TO_VM_MAP_ENTRY(map->holes_list);
+                       } else {
+                               l_next = CAST_TO_VM_MAP_ENTRY(map->holes_list);
+                               l_prev = map->holes_list->prev;
+                               map->holes_list = new_hole_entry;
+                               new_hole_entry->next = l_next;
+                               new_hole_entry->prev = l_prev;
+
+                               l_prev->vme_next = l_next->vme_prev = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+                       }
+               } else {
+                       l_next = hole_entry->vme_next;
+                       l_prev = hole_entry->vme_next->vme_prev;
+
+                       new_hole_entry->prev = hole_entry;
+                       new_hole_entry->next = l_next;
+
+                       hole_entry->vme_next = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+                       l_next->vme_prev = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+               }
+
+               new_hole_entry->start = old_entry->vme_start;
+               new_hole_entry->end = old_entry->vme_end;
+
+               hole_entry = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+
+               assert(new_hole_entry->start < new_hole_entry->end);
+       }
+
+#if DEBUG
+       if (vm_check_map_sanity) {
+               check_map_sanity(map, &old_hole_entry);
+       }
+#endif /* DEBUG */
+
+       SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) hole_entry);
+       return;
+}
+
+
+void
+update_holes_on_entry_creation(vm_map_t map, vm_map_entry_t new_entry);
+void
+update_holes_on_entry_creation(vm_map_t map, vm_map_entry_t new_entry)
+{
+       vm_map_entry_t                  hole_entry, next_hole_entry;
+#if DEBUG
+       struct vm_map_entry             old_hole_entry;
+       vm_map_entry_t                  tmp_entry;
+       boolean_t                               check_map_with_hole_sanity = TRUE;
+#endif /* DEBUG */
+
+       /*
+        * Case A: The entry is aligned exactly with the start and end of the hole.
+        *         This will delete the hole.
+        *
+        * Case B: The entry is completely within a hole but NOT aligned with the start/end of the hole.
+        *         This  will split a hole.
+        *
+        * Case C: The entry overlaps with the hole. The entry could be extending upwards (C1) or downwards (C2).
+        *         This will reduce the size of the hole or delete the hole completely if it is smaller than the entry.
+        */
+
+       hole_entry = CAST_TO_VM_MAP_ENTRY(map->holes_list);
+       assert(hole_entry);
+       next_hole_entry = hole_entry->vme_next;
+
+       while (1) {
+#if DEBUG
+               /*
+                * If the entry doesn't exist in the RB tree, we are likely dealing with copy maps where
+                * the entries belonging to the copy map are linked into the list of entries silently and
+                * then added to the RB-tree later on.
+                * So sanity checks are useless in that case.
+                */
+               check_map_with_hole_sanity = vm_map_lookup_entry(map, new_entry->vme_start, &tmp_entry);
+#endif /* DEBUG */
+
+               if (hole_entry->vme_start == new_entry->vme_start &&
+                   hole_entry->vme_end == new_entry->vme_end) {
+                       /* Case A */
+#if DEBUG
+                       copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                       /*
+                        * This check makes sense only for regular maps, not copy maps.
+                        * With a regular map, the VM entry is first linked and then
+                        * the hole is deleted. So the check below, which makes sure that
+                        * the map's bounds are being respected, is valid.
+                        * But for copy maps, the hole is deleted before the VM entry is
+                        * linked (vm_map_store_copy_insert) and so this check is invalid.
+                        *
+                        *  if (hole_entry == (vm_map_entry_t) map->holes_list) {
+                        *
+                        *       if (hole_entry->vme_next == (vm_map_entry_t) map->holes_list) {
+                        *
+                        *               next_hole_entry = vm_map_last_entry(map);
+                        *               assert(next_hole_entry->vme_end >= map->max_offset);
+                        *       }
+                        *  }
+                        */
+
+                       vm_map_delete_hole(map, hole_entry);
+
+#if DEBUG
+                       if (vm_check_map_sanity && check_map_with_hole_sanity) {
+                               check_map_sanity(map, &old_hole_entry);
+                       }
+#endif /* DEBUG */
+                       return;
+               } else if (hole_entry->vme_start < new_entry->vme_start &&
+                   hole_entry->vme_end > new_entry->vme_end) {
+                       /* Case B */
+                       struct vm_map_links *new_hole_entry = NULL;
+
+                       new_hole_entry = zalloc(vm_map_holes_zone);
+
+#if DEBUG
+                       copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                       new_hole_entry->prev = hole_entry;
+                       new_hole_entry->next = hole_entry->vme_next;
+                       hole_entry->vme_next->vme_prev = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+                       hole_entry->vme_next = CAST_TO_VM_MAP_ENTRY(new_hole_entry);
+
+                       new_hole_entry->start = new_entry->vme_end;
+                       new_hole_entry->end = hole_entry->vme_end;
+                       hole_entry->vme_end = new_entry->vme_start;
+
+                       assert(hole_entry->vme_start < hole_entry->vme_end);
+                       assert(new_hole_entry->start < new_hole_entry->end);
+
+#if DEBUG
+                       if (vm_check_map_sanity && check_map_with_hole_sanity) {
+                               check_map_sanity(map, &old_hole_entry);
+                       }
+#endif /* DEBUG */
+
+                       SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) hole_entry);
+                       return;
+               } else if ((new_entry->vme_start <= hole_entry->vme_start) && (hole_entry->vme_start < new_entry->vme_end)) {
+                       /*
+                        * Case C1: Entry moving upwards and a part/full hole lies within the bounds of the entry.
+                        */
+
+#if DEBUG
+                       copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                       if (hole_entry->vme_end <= new_entry->vme_end) {
+                               vm_map_delete_hole(map, hole_entry);
+                       } else {
+                               hole_entry->vme_start = new_entry->vme_end;
+                               SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) hole_entry);
+                       }
+
+#if DEBUG
+                       if (vm_check_map_sanity && check_map_with_hole_sanity) {
+                               check_map_sanity(map, &old_hole_entry);
+                       }
+#endif /* DEBUG */
+
+                       return;
+               } else if ((new_entry->vme_start < hole_entry->vme_end) && (hole_entry->vme_end <= new_entry->vme_end)) {
+                       /*
+                        * Case C2: Entry moving downwards and a part/full hole lies within the bounds of the entry.
+                        */
+
+#if DEBUG
+                       copy_hole_info(hole_entry, &old_hole_entry);
+#endif /* DEBUG */
+
+                       if (hole_entry->vme_start >= new_entry->vme_start) {
+                               vm_map_delete_hole(map, hole_entry);
+                       } else {
+                               hole_entry->vme_end = new_entry->vme_start;
+                               SAVE_HINT_HOLE_WRITE(map, (struct vm_map_links*) hole_entry);
+                       }
+
+#if DEBUG
+                       if (vm_check_map_sanity && check_map_with_hole_sanity) {
+                               check_map_sanity(map, &old_hole_entry);
+                       }
+#endif /* DEBUG */
+
+                       return;
+               }
+
+               hole_entry = next_hole_entry;
+               next_hole_entry = hole_entry->vme_next;
+
+               if (hole_entry == CAST_TO_VM_MAP_ENTRY(map->holes_list)) {
+                       break;
+               }
+       }
+
+       panic("Illegal action: h1: %p, s:0x%llx, e:0x%llx...h2:%p, s:0x%llx, e:0x%llx...h3:0x%p, s:0x%llx, e:0x%llx\n",
+           hole_entry->vme_prev,
+           (unsigned long long)hole_entry->vme_prev->vme_start,
+           (unsigned long long)hole_entry->vme_prev->vme_end,
+           hole_entry,
+           (unsigned long long)hole_entry->vme_start,
+           (unsigned long long)hole_entry->vme_end,
+           hole_entry->vme_next,
+           (unsigned long long)hole_entry->vme_next->vme_start,
+           (unsigned long long)hole_entry->vme_next->vme_end);
+}
+
+void
+update_first_free_rb(vm_map_t map, vm_map_entry_t entry, boolean_t new_entry_creation)
+{
+       if (map->holelistenabled) {
+               /*
+                * Holes can be used to track ranges all the way up to MACH_VM_MAX_ADDRESS or more (e.g. kernel map).
+                */
+               vm_map_offset_t max_valid_offset = (map->max_offset > MACH_VM_MAX_ADDRESS) ? map->max_offset : MACH_VM_MAX_ADDRESS;
+
+               /*
+                * Clipping an entry will not result in the creation/deletion/modification of
+                * a hole. Those calls pass NULL for their target entry.
+                */
+               if (entry == NULL) {
+                       return;
+               }
+
+               /*
+                * Commpage is pinned beyond the map's max offset. That shouldn't affect the
+                * holes within the bounds of the map.
+                */
+               if (vm_map_trunc_page(entry->vme_start, VM_MAP_PAGE_MASK(map)) >= max_valid_offset) {
+                       return;
+               }
+
+               /*
+                *
+                * Note:
+                *
+                * - A new entry has already been added to the map
+                * OR
+                * - An older entry has already been deleted from the map
+                *
+                * We are updating the hole list after the fact (except in one special case involving copy maps).
+                *
+                */
+
+               if (new_entry_creation) {
+                       update_holes_on_entry_creation(map, entry);
+               } else {
+                       update_holes_on_entry_deletion(map, entry);
+               }
+       }
+}