1 /* 2 * Copyright (c) 2000 Peter Wemm 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/linker_set.h> 31 #include <sys/conf.h> 32 #include <sys/kernel.h> 33 #include <sys/lock.h> 34 #include <sys/mutex.h> 35 #include <sys/mman.h> 36 #include <sys/sysctl.h> 37 #include <sys/sx.h> 38 39 #include <vm/vm.h> 40 #include <vm/vm_object.h> 41 #include <vm/vm_page.h> 42 #include <vm/vm_pager.h> 43 #include <vm/vm_zone.h> 44 45 /* prevent concurrant creation races */ 46 static struct sx phys_pager_sx; 47 /* list of device pager objects */ 48 static struct pagerlst phys_pager_object_list; 49 /* protect access to phys_pager_object_list */ 50 static struct mtx phys_pager_mtx; 51 52 static void 53 phys_pager_init(void) 54 { 55 56 TAILQ_INIT(&phys_pager_object_list); 57 sx_init(&phys_pager_sx, "phys_pager create"); 58 mtx_init(&phys_pager_mtx, "phys_pager list", MTX_DEF); 59 } 60 61 static vm_object_t 62 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 63 vm_ooffset_t foff) 64 { 65 vm_object_t object; 66 67 /* 68 * Offset should be page aligned. 69 */ 70 if (foff & PAGE_MASK) 71 return (NULL); 72 73 size = round_page(size); 74 75 if (handle != NULL) { 76 /* 77 * Lock to prevent object creation race condition. 78 */ 79 sx_xlock(&phys_pager_sx); 80 81 /* 82 * Look up pager, creating as necessary. 83 */ 84 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 85 if (object == NULL) { 86 /* 87 * Allocate object and associate it with the pager. 88 */ 89 object = vm_object_allocate(OBJT_PHYS, 90 OFF_TO_IDX(foff + size)); 91 object->handle = handle; 92 mtx_lock(&phys_pager_mtx); 93 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 94 pager_object_list); 95 mtx_unlock(&phys_pager_mtx); 96 } else { 97 /* 98 * Gain a reference to the object. 99 */ 100 vm_object_reference(object); 101 if (OFF_TO_IDX(foff + size) > object->size) 102 object->size = OFF_TO_IDX(foff + size); 103 } 104 sx_xunlock(&phys_pager_sx); 105 } else { 106 object = vm_object_allocate(OBJT_PHYS, 107 OFF_TO_IDX(foff + size)); 108 } 109 110 return (object); 111 } 112 113 static void 114 phys_pager_dealloc(vm_object_t object) 115 { 116 117 if (object->handle != NULL) { 118 mtx_lock(&phys_pager_mtx); 119 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 120 mtx_unlock(&phys_pager_mtx); 121 } 122 } 123 124 static int 125 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 126 { 127 int i, s; 128 129 s = splvm(); 130 /* 131 * Fill as many pages as vm_fault has allocated for us. 132 */ 133 for (i = 0; i < count; i++) { 134 if ((m[i]->flags & PG_ZERO) == 0) 135 vm_page_zero_fill(m[i]); 136 vm_page_flag_set(m[i], PG_ZERO); 137 /* Switch off pv_entries */ 138 vm_page_unmanage(m[i]); 139 m[i]->valid = VM_PAGE_BITS_ALL; 140 m[i]->dirty = 0; 141 /* The requested page must remain busy, the others not. */ 142 if (reqpage != i) { 143 vm_page_flag_clear(m[i], PG_BUSY); 144 m[i]->busy = 0; 145 } 146 } 147 splx(s); 148 149 return (VM_PAGER_OK); 150 } 151 152 static void 153 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 154 int *rtvals) 155 { 156 157 panic("phys_pager_putpage called"); 158 } 159 160 /* 161 * Implement a pretty aggressive clustered getpages strategy. Hint that 162 * everything in an entire 4MB window should be prefaulted at once. 163 * 164 * XXX 4MB (1024 slots per page table page) is convenient for x86, 165 * but may not be for other arches. 166 */ 167 #ifndef PHYSCLUSTER 168 #define PHYSCLUSTER 1024 169 #endif 170 static boolean_t 171 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 172 int *after) 173 { 174 vm_pindex_t base, end; 175 176 base = pindex & (~(PHYSCLUSTER - 1)); 177 end = base + (PHYSCLUSTER - 1); 178 if (before != NULL) 179 *before = pindex - base; 180 if (after != NULL) 181 *after = end - pindex; 182 return (TRUE); 183 } 184 185 struct pagerops physpagerops = { 186 phys_pager_init, 187 phys_pager_alloc, 188 phys_pager_dealloc, 189 phys_pager_getpages, 190 phys_pager_putpages, 191 phys_pager_haspage, 192 NULL 193 }; 194