FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_map.h

     /*-
      * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
      *
      * Copyright (c) 1991, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * This code is derived from software contributed to Berkeley by
      * The Mach Operating System project at Carnegie-Mellon University.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. 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.
     *
     *      @(#)vm_map.h    8.9 (Berkeley) 5/17/95
     *
     *
     * Copyright (c) 1987, 1990 Carnegie-Mellon University.
     * All rights reserved.
     *
     * Authors: Avadis Tevanian, Jr., Michael Wayne Young
     *
     * Permission to use, copy, modify and distribute this software and
     * its documentation is hereby granted, provided that both the copyright
     * notice and this permission notice appear in all copies of the
     * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     *
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     *
     * Carnegie Mellon requests users of this software to return to
     *
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     *
     * any improvements or extensions that they make and grant Carnegie the
     * rights to redistribute these changes.
     *
     * $FreeBSD$
     */
    
    /*
     *      Virtual memory map module definitions.
     */
    #ifndef _VM_MAP_
    #define _VM_MAP_
    
    #include <sys/lock.h>
    #include <sys/sx.h>
    #include <sys/_mutex.h>
    
    /*
     *      Types defined:
     *
     *      vm_map_t                the high-level address map data structure.
     *      vm_map_entry_t          an entry in an address map.
     */
    
    typedef u_char vm_flags_t;
    typedef u_int vm_eflags_t;
    
    /*
     *      Objects which live in maps may be either VM objects, or
     *      another map (called a "sharing map") which denotes read-write
     *      sharing with other maps.
     */
    union vm_map_object {
            struct vm_object *vm_object;    /* object object */
            struct vm_map *sub_map;         /* belongs to another map */
    };
    
    /*
     *      Address map entries consist of start and end addresses,
     *      a VM object (or sharing map) and offset into that object,
     *      and user-exported inheritance and protection information.
     *      Also included is control information for virtual copy operations.
    */
   struct vm_map_entry {
           struct vm_map_entry *left;      /* left child or previous entry */
           struct vm_map_entry *right;     /* right child or next entry */
           vm_offset_t start;              /* start address */
           vm_offset_t end;                /* end address */
           vm_offset_t next_read;          /* vaddr of the next sequential read */
           vm_size_t max_free;             /* max free space in subtree */
           union vm_map_object object;     /* object I point to */
           vm_ooffset_t offset;            /* offset into object */
           vm_eflags_t eflags;             /* map entry flags */
           vm_prot_t protection;           /* protection code */
           vm_prot_t max_protection;       /* maximum protection */
           vm_inherit_t inheritance;       /* inheritance */
           uint8_t read_ahead;             /* pages in the read-ahead window */
           int wired_count;                /* can be paged if = 0 */
           struct ucred *cred;             /* tmp storage for creator ref */
           struct thread *wiring_thread;
   };
   
   #define MAP_ENTRY_NOSYNC                0x00000001
   #define MAP_ENTRY_IS_SUB_MAP            0x00000002
   #define MAP_ENTRY_COW                   0x00000004
   #define MAP_ENTRY_NEEDS_COPY            0x00000008
   #define MAP_ENTRY_NOFAULT               0x00000010
   #define MAP_ENTRY_USER_WIRED            0x00000020
   
   #define MAP_ENTRY_BEHAV_NORMAL          0x00000000      /* default behavior */
   #define MAP_ENTRY_BEHAV_SEQUENTIAL      0x00000040      /* expect sequential
                                                              access */
   #define MAP_ENTRY_BEHAV_RANDOM          0x00000080      /* expect random
                                                              access */
   #define MAP_ENTRY_BEHAV_RESERVED        0x000000c0      /* future use */
   #define MAP_ENTRY_BEHAV_MASK            0x000000c0
   #define MAP_ENTRY_IN_TRANSITION         0x00000100      /* entry being
                                                              changed */
   #define MAP_ENTRY_NEEDS_WAKEUP          0x00000200      /* waiters in
                                                              transition */
   #define MAP_ENTRY_NOCOREDUMP            0x00000400      /* don't include in
                                                              a core */
   #define MAP_ENTRY_VN_EXEC               0x00000800      /* text vnode mapping */
   #define MAP_ENTRY_GROWS_DOWN            0x00001000      /* top-down stacks */
   #define MAP_ENTRY_GROWS_UP              0x00002000      /* bottom-up stacks */
   
   #define MAP_ENTRY_WIRE_SKIPPED          0x00004000
   #define MAP_ENTRY_WRITECNT              0x00008000      /* tracked writeable
                                                              mapping */
   #define MAP_ENTRY_GUARD                 0x00010000
   #define MAP_ENTRY_STACK_GAP_DN          0x00020000
   #define MAP_ENTRY_STACK_GAP_UP          0x00040000
   #define MAP_ENTRY_HEADER                0x00080000
   
   #define MAP_ENTRY_SPLIT_BOUNDARY_MASK   0x00300000
   
   #define MAP_ENTRY_SPLIT_BOUNDARY_SHIFT  20
   
   #ifdef  _KERNEL
   static __inline u_char
   vm_map_entry_behavior(vm_map_entry_t entry)
   {
           return (entry->eflags & MAP_ENTRY_BEHAV_MASK);
   }
   
   static __inline int
   vm_map_entry_user_wired_count(vm_map_entry_t entry)
   {
           if (entry->eflags & MAP_ENTRY_USER_WIRED)
                   return (1);
           return (0);
   }
   
   static __inline int
   vm_map_entry_system_wired_count(vm_map_entry_t entry)
   {
           return (entry->wired_count - vm_map_entry_user_wired_count(entry));
   }
   #endif  /* _KERNEL */
   
   /*
    *      A map is a set of map entries.  These map entries are
    *      organized as a threaded binary search tree.  Both structures
    *      are ordered based upon the start and end addresses contained
    *      within each map entry.  The largest gap between an entry in a
    *      subtree and one of its neighbors is saved in the max_free
    *      field, and that field is updated when the tree is
    *      restructured.
    *
    *      Sleator and Tarjan's top-down splay algorithm is employed to
    *      control height imbalance in the binary search tree.
    *
    *      The map's min offset value is stored in map->header.end, and
    *      its max offset value is stored in map->header.start.  These
    *      values act as sentinels for any forward or backward address
    *      scan of the list.  The right and left fields of the map
    *      header point to the first and list map entries.  The map
    *      header has a special value for the eflags field,
    *      MAP_ENTRY_HEADER, that is set initially, is never changed,
    *      and prevents an eflags match of the header with any other map
    *      entry.
    *
    *      List of locks
    *      (c)     const until freed
    */
   struct vm_map {
           struct vm_map_entry header;     /* List of entries */
           struct sx lock;                 /* Lock for map data */
           struct mtx system_mtx;
           int nentries;                   /* Number of entries */
           vm_size_t size;                 /* virtual size */
           u_int timestamp;                /* Version number */
           u_char needs_wakeup;
           u_char system_map;              /* (c) Am I a system map? */
           vm_flags_t flags;               /* flags for this vm_map */
           vm_map_entry_t root;            /* Root of a binary search tree */
           pmap_t pmap;                    /* (c) Physical map */
           vm_offset_t anon_loc;
           int busy;
   #ifdef DIAGNOSTIC
           int nupdates;
   #endif
   };
   
   /*
    * vm_flags_t values
    */
   #define MAP_WIREFUTURE          0x01    /* wire all future pages */
   #define MAP_BUSY_WAKEUP         0x02    /* thread(s) waiting on busy state */
   #define MAP_IS_SUB_MAP          0x04    /* has parent */
   #define MAP_ASLR                0x08    /* enabled ASLR */
   #define MAP_ASLR_IGNSTART       0x10    /* ASLR ignores data segment */
   #define MAP_REPLENISH           0x20    /* kmapent zone needs to be refilled */
   #define MAP_WXORX               0x40    /* enforce W^X */
   #define MAP_ASLR_STACK          0x80    /* stack location is randomized */
   
   #ifdef  _KERNEL
   #if defined(KLD_MODULE) && !defined(KLD_TIED)
   #define vm_map_max(map)         vm_map_max_KBI((map))
   #define vm_map_min(map)         vm_map_min_KBI((map))
   #define vm_map_pmap(map)        vm_map_pmap_KBI((map))
   #define vm_map_range_valid(map, start, end)     \
           vm_map_range_valid_KBI((map), (start), (end))
   #else
   static __inline vm_offset_t
   vm_map_max(const struct vm_map *map)
   {
   
           return (map->header.start);
   }
   
   static __inline vm_offset_t
   vm_map_min(const struct vm_map *map)
   {
   
           return (map->header.end);
   }
   
   static __inline pmap_t
   vm_map_pmap(vm_map_t map)
   {
           return (map->pmap);
   }
   
   static __inline void
   vm_map_modflags(vm_map_t map, vm_flags_t set, vm_flags_t clear)
   {
           map->flags = (map->flags | set) & ~clear;
   }
   
   static inline bool
   vm_map_range_valid(vm_map_t map, vm_offset_t start, vm_offset_t end)
   {
           if (end < start)
                   return (false);
           if (start < vm_map_min(map) || end > vm_map_max(map))
                   return (false);
           return (true);
   }
   
   #endif  /* KLD_MODULE */
   #endif  /* _KERNEL */
   
   /*
    * Shareable process virtual address space.
    *
    * List of locks
    *      (c)     const until freed
    */
   struct vmspace {
           struct vm_map vm_map;   /* VM address map */
           struct shmmap_state *vm_shm;    /* SYS5 shared memory private data XXX */
           segsz_t vm_swrss;       /* resident set size before last swap */
           segsz_t vm_tsize;       /* text size (pages) XXX */
           segsz_t vm_dsize;       /* data size (pages) XXX */
           segsz_t vm_ssize;       /* stack size (pages) */
           caddr_t vm_taddr;       /* (c) user virtual address of text */
           caddr_t vm_daddr;       /* (c) user virtual address of data */
           caddr_t vm_maxsaddr;    /* user VA at max stack growth */
           vm_offset_t vm_stacktop; /* top of the stack, may not be page-aligned */
           vm_offset_t vm_shp_base; /* shared page address */
           u_int vm_refcnt;        /* number of references */
           /*
            * Keep the PMAP last, so that CPU-specific variations of that
            * structure on a single architecture don't result in offset
            * variations of the machine-independent fields in the vmspace.
            */
           struct pmap vm_pmap;    /* private physical map */
   };
   
   #ifdef  _KERNEL
   static __inline pmap_t
   vmspace_pmap(struct vmspace *vmspace)
   {
           return &vmspace->vm_pmap;
   }
   #endif  /* _KERNEL */
   
   #ifdef  _KERNEL
   /*
    *      Macros:         vm_map_lock, etc.
    *      Function:
    *              Perform locking on the data portion of a map.  Note that
    *              these macros mimic procedure calls returning void.  The
    *              semicolon is supplied by the user of these macros, not
    *              by the macros themselves.  The macros can safely be used
    *              as unbraced elements in a higher level statement.
    */
   
   void _vm_map_lock(vm_map_t map, const char *file, int line);
   void _vm_map_unlock(vm_map_t map, const char *file, int line);
   int _vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line);
   void _vm_map_lock_read(vm_map_t map, const char *file, int line);
   void _vm_map_unlock_read(vm_map_t map, const char *file, int line);
   int _vm_map_trylock(vm_map_t map, const char *file, int line);
   int _vm_map_trylock_read(vm_map_t map, const char *file, int line);
   int _vm_map_lock_upgrade(vm_map_t map, const char *file, int line);
   void _vm_map_lock_downgrade(vm_map_t map, const char *file, int line);
   int vm_map_locked(vm_map_t map);
   void vm_map_wakeup(vm_map_t map);
   void vm_map_busy(vm_map_t map);
   void vm_map_unbusy(vm_map_t map);
   void vm_map_wait_busy(vm_map_t map);
   vm_offset_t vm_map_max_KBI(const struct vm_map *map);
   vm_offset_t vm_map_min_KBI(const struct vm_map *map);
   pmap_t vm_map_pmap_KBI(vm_map_t map);
   bool vm_map_range_valid_KBI(vm_map_t map, vm_offset_t start, vm_offset_t end);
   
   #define vm_map_lock(map)        _vm_map_lock(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_unlock(map)      _vm_map_unlock(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_unlock_and_wait(map, timo)       \
                           _vm_map_unlock_and_wait(map, timo, LOCK_FILE, LOCK_LINE)
   #define vm_map_lock_read(map)   _vm_map_lock_read(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_unlock_read(map) _vm_map_unlock_read(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_trylock(map)     _vm_map_trylock(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_trylock_read(map)        \
                           _vm_map_trylock_read(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_lock_upgrade(map)        \
                           _vm_map_lock_upgrade(map, LOCK_FILE, LOCK_LINE)
   #define vm_map_lock_downgrade(map)      \
                           _vm_map_lock_downgrade(map, LOCK_FILE, LOCK_LINE)
   
   long vmspace_resident_count(struct vmspace *vmspace);
   #endif  /* _KERNEL */
   
   /*
    * Copy-on-write flags for vm_map operations
    */
   #define MAP_INHERIT_SHARE       0x00000001
   #define MAP_COPY_ON_WRITE       0x00000002
   #define MAP_NOFAULT             0x00000004
   #define MAP_PREFAULT            0x00000008
   #define MAP_PREFAULT_PARTIAL    0x00000010
   #define MAP_DISABLE_SYNCER      0x00000020
   #define MAP_CHECK_EXCL          0x00000040
   #define MAP_CREATE_GUARD        0x00000080
   #define MAP_DISABLE_COREDUMP    0x00000100
   #define MAP_PREFAULT_MADVISE    0x00000200    /* from (user) madvise request */
   #define MAP_WRITECOUNT          0x00000400
   #define MAP_REMAP               0x00000800
   #define MAP_STACK_GROWS_DOWN    0x00001000
   #define MAP_STACK_GROWS_UP      0x00002000
   #define MAP_ACC_CHARGED         0x00004000
   #define MAP_ACC_NO_CHARGE       0x00008000
   #define MAP_CREATE_STACK_GAP_UP 0x00010000
   #define MAP_CREATE_STACK_GAP_DN 0x00020000
   #define MAP_VN_EXEC             0x00040000
   #define MAP_SPLIT_BOUNDARY_MASK 0x00180000
   
   #define MAP_SPLIT_BOUNDARY_SHIFT 19
   
   /*
    * vm_fault option flags
    */
   #define VM_FAULT_NORMAL 0x00    /* Nothing special */
   #define VM_FAULT_WIRE   0x01    /* Wire the mapped page */
   #define VM_FAULT_DIRTY  0x02    /* Dirty the page; use w/VM_PROT_COPY */
   #define VM_FAULT_NOFILL 0x04    /* Fail if the pager doesn't have a copy */
   
   /*
    * Initially, mappings are slightly sequential.  The maximum window size must
    * account for the map entry's "read_ahead" field being defined as an uint8_t.
    */
   #define VM_FAULT_READ_AHEAD_MIN         7
   #define VM_FAULT_READ_AHEAD_INIT        15
   #define VM_FAULT_READ_AHEAD_MAX         min(atop(maxphys) - 1, UINT8_MAX)
   
   /*
    * The following "find_space" options are supported by vm_map_find().
    *
    * For VMFS_ALIGNED_SPACE, the desired alignment is specified to
    * the macro argument as log base 2 of the desired alignment.
    */
   #define VMFS_NO_SPACE           0       /* don't find; use the given range */
   #define VMFS_ANY_SPACE          1       /* find a range with any alignment */
   #define VMFS_OPTIMAL_SPACE      2       /* find a range with optimal alignment*/
   #define VMFS_SUPER_SPACE        3       /* find a superpage-aligned range */
   #define VMFS_ALIGNED_SPACE(x)   ((x) << 8) /* find a range with fixed alignment */
   
   /*
    * vm_map_wire and vm_map_unwire option flags
    */
   #define VM_MAP_WIRE_SYSTEM      0       /* wiring in a kernel map */
   #define VM_MAP_WIRE_USER        1       /* wiring in a user map */
   
   #define VM_MAP_WIRE_NOHOLES     0       /* region must not have holes */
   #define VM_MAP_WIRE_HOLESOK     2       /* region may have holes */
   
   #define VM_MAP_WIRE_WRITE       4       /* Validate writable. */
   
   typedef int vm_map_entry_reader(void *token, vm_map_entry_t addr, 
       vm_map_entry_t dest);
   
   #ifndef _KERNEL
   /*
    * Find the successor of a map_entry, using a reader to dereference pointers.
    * '*clone' is a copy of a vm_map entry.  'reader' is used to copy a map entry
    * at some address into '*clone'.  Change *clone to a copy of the next map
    * entry, and return the address of that entry, or NULL if copying has failed.
    *
    * This function is made available to user-space code that needs to traverse
    * map entries.
    */
   static inline vm_map_entry_t
   vm_map_entry_read_succ(void *token, struct vm_map_entry *const clone,
       vm_map_entry_reader reader)
   {
           vm_map_entry_t after, backup;
           vm_offset_t start;
   
           after = clone->right;
           start = clone->start;
           if (!reader(token, after, clone))
                   return (NULL);
           backup = clone->left;
           if (!reader(token, backup, clone))
                   return (NULL);
           if (clone->start > start) {
                   do {
                           after = backup;
                           backup = clone->left;
                           if (!reader(token, backup, clone))
                                   return (NULL);
                   } while (clone->start != start);
           }
           if (!reader(token, after, clone))
                   return (NULL);
           return (after);
   }
   #endif                          /* ! _KERNEL */
   
   #ifdef _KERNEL
   boolean_t vm_map_check_protection (vm_map_t, vm_offset_t, vm_offset_t, vm_prot_t);
   int vm_map_delete(vm_map_t, vm_offset_t, vm_offset_t);
   int vm_map_find(vm_map_t, vm_object_t, vm_ooffset_t, vm_offset_t *, vm_size_t,
       vm_offset_t, int, vm_prot_t, vm_prot_t, int);
   int vm_map_find_min(vm_map_t, vm_object_t, vm_ooffset_t, vm_offset_t *,
       vm_size_t, vm_offset_t, vm_offset_t, int, vm_prot_t, vm_prot_t, int);
   int vm_map_find_aligned(vm_map_t map, vm_offset_t *addr, vm_size_t length,
       vm_offset_t max_addr, vm_offset_t alignment);
   int vm_map_fixed(vm_map_t, vm_object_t, vm_ooffset_t, vm_offset_t, vm_size_t,
       vm_prot_t, vm_prot_t, int);
   vm_offset_t vm_map_findspace(vm_map_t, vm_offset_t, vm_size_t);
   int vm_map_inherit (vm_map_t, vm_offset_t, vm_offset_t, vm_inherit_t);
   void vm_map_init(vm_map_t, pmap_t, vm_offset_t, vm_offset_t);
   int vm_map_insert (vm_map_t, vm_object_t, vm_ooffset_t, vm_offset_t, vm_offset_t, vm_prot_t, vm_prot_t, int);
   int vm_map_lookup (vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *, vm_object_t *,
       vm_pindex_t *, vm_prot_t *, boolean_t *);
   int vm_map_lookup_locked(vm_map_t *, vm_offset_t, vm_prot_t, vm_map_entry_t *, vm_object_t *,
       vm_pindex_t *, vm_prot_t *, boolean_t *);
   void vm_map_lookup_done (vm_map_t, vm_map_entry_t);
   boolean_t vm_map_lookup_entry (vm_map_t, vm_offset_t, vm_map_entry_t *);
   
   static inline vm_map_entry_t
   vm_map_entry_first(vm_map_t map)
   {
   
           return (map->header.right);
   }
   
   static inline vm_map_entry_t
   vm_map_entry_succ(vm_map_entry_t entry)
   {
           vm_map_entry_t after;
   
           after = entry->right;
           if (after->left->start > entry->start) {
                   do
                           after = after->left;
                   while (after->left != entry);
           }
           return (after);
   }
   
   #define VM_MAP_ENTRY_FOREACH(it, map)           \
           for ((it) = vm_map_entry_first(map);    \
               (it) != &(map)->header;             \
               (it) = vm_map_entry_succ(it))
   
   #define VM_MAP_PROTECT_SET_PROT         0x0001
   #define VM_MAP_PROTECT_SET_MAXPROT      0x0002
   
   int vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
       vm_prot_t new_prot, vm_prot_t new_maxprot, int flags);
   int vm_map_remove (vm_map_t, vm_offset_t, vm_offset_t);
   void vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev,
       vm_map_entry_t entry);
   void vm_map_startup (void);
   int vm_map_submap (vm_map_t, vm_offset_t, vm_offset_t, vm_map_t);
   int vm_map_sync(vm_map_t, vm_offset_t, vm_offset_t, boolean_t, boolean_t);
   int vm_map_madvise (vm_map_t, vm_offset_t, vm_offset_t, int);
   int vm_map_stack (vm_map_t, vm_offset_t, vm_size_t, vm_prot_t, vm_prot_t, int);
   int vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
       int flags);
   int vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags);
   int vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end,
       int flags);
   long vmspace_swap_count(struct vmspace *vmspace);
   void vm_map_entry_set_vnode_text(vm_map_entry_t entry, bool add);
   #endif                          /* _KERNEL */
   #endif                          /* _VM_MAP_ */

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