vm_map.h

Go to the documentation of this file.

/*-
 * 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 */
        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_ */