1 /* $NetBSD: uvm_object.h,v 1.39 2020/08/14 09:06:15 chs Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp 28 */ 29 30 #ifndef _UVM_UVM_OBJECT_H_ 31 #define _UVM_UVM_OBJECT_H_ 32 33 #include <sys/queue.h> 34 #include <sys/radixtree.h> 35 #include <uvm/uvm_pglist.h> 36 37 /* 38 * The UVM memory object interface. Notes: 39 * 40 * A UVM memory object represents a list of pages, which are managed by 41 * the object's pager operations (uvm_object::pgops). All pages belonging 42 * to an object are owned by it and thus protected by the object lock. 43 * 44 * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects. 45 * By default, the lock is allocated dynamically using mutex_obj(9) cache. 46 * Lock sharing is normally used when there is an underlying object. For 47 * example, vnode representing a file may have an underlying node, which 48 * is the case for tmpfs and layered file systems. In such case, vnode's 49 * UVM object and the underlying UVM object shares the lock (note that the 50 * vnode_t::v_interlock points to uvm_object::vmobjlock). 51 * 52 * The reference count is managed atomically for the anonymous UVM objects. 53 * For other objects, it is arbitrary (may use the lock or atomics). 54 */ 55 56 struct krwlock; 57 struct uvm_object { 58 struct krwlock * vmobjlock; /* lock on object */ 59 const struct uvm_pagerops *pgops; /* pager ops */ 60 int uo_npages; /* # of pages in uo_pages */ 61 unsigned uo_refs; /* reference count */ 62 struct radix_tree uo_pages; /* tree of pages */ 63 LIST_HEAD(,ubc_map) uo_ubc; /* ubc mappings */ 64 }; 65 66 /* 67 * tags for uo_pages 68 */ 69 70 #define UVM_PAGE_DIRTY_TAG 1 /* might be dirty (!PG_CLEAN) */ 71 #define UVM_PAGE_WRITEBACK_TAG 2 /* being written back */ 72 73 /* 74 * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the 75 * object is a kernel memory object rather than a normal one (kernel 76 * memory objects don't have reference counts -- they never die). 77 * 78 * this value is used to detected kernel object mappings at uvm_unmap() 79 * time. normally when an object is unmapped its pages eventaully become 80 * deactivated and then paged out and/or freed. this is not useful 81 * for kernel objects... when a kernel object is unmapped we always want 82 * to free the resources associated with the mapping. UVM_OBJ_KERN 83 * allows us to decide which type of unmapping we want to do. 84 */ 85 #define UVM_OBJ_KERN (-2) 86 87 #define UVM_OBJ_IS_KERN_OBJECT(uobj) \ 88 ((uobj)->uo_refs == UVM_OBJ_KERN) 89 90 #ifdef _KERNEL 91 92 extern const struct uvm_pagerops uvm_vnodeops; 93 extern const struct uvm_pagerops uvm_deviceops; 94 extern const struct uvm_pagerops ubc_pager; 95 extern const struct uvm_pagerops aobj_pager; 96 97 #define UVM_OBJ_IS_VNODE(uobj) \ 98 ((uobj)->pgops == &uvm_vnodeops) 99 100 #define UVM_OBJ_IS_DEVICE(uobj) \ 101 ((uobj)->pgops == &uvm_deviceops) 102 103 #define UVM_OBJ_IS_VTEXT(uobj) \ 104 (UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj)) 105 106 #define UVM_OBJ_IS_CLEAN(uobj) \ 107 (UVM_OBJ_IS_VNODE(uobj) && uvm_obj_clean_p(uobj)) 108 109 /* 110 * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification. 111 * (ie. wants to avoid writable user mappings.) 112 * 113 * XXX bad name 114 */ 115 116 #define UVM_OBJ_NEEDS_WRITEFAULT(uobj) \ 117 (UVM_OBJ_IS_VNODE(uobj) && uvm_obj_clean_p(uobj)) 118 119 #define UVM_OBJ_IS_AOBJ(uobj) \ 120 ((uobj)->pgops == &aobj_pager) 121 122 #endif /* _KERNEL */ 123 124 #endif /* _UVM_UVM_OBJECT_H_ */ 125