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 38 #include <vm/vm.h> 39 #include <vm/vm_object.h> 40 #include <vm/vm_page.h> 41 #include <vm/vm_pager.h> 42 #include <vm/vm_zone.h> 43 44 /* prevent concurrant creation races */ 45 static int phys_pager_alloc_lock; 46 /* list of device pager objects */ 47 static struct pagerlst phys_pager_object_list; 48 /* protect access to phys_pager_object_list */ 49 static struct mtx phys_pager_mtx; 50 51 static void 52 phys_pager_init(void) 53 { 54 55 TAILQ_INIT(&phys_pager_object_list); 56 mtx_init(&phys_pager_mtx, "phys_pager list", MTX_DEF); 57 } 58 59 static vm_object_t 60 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 61 vm_ooffset_t foff) 62 { 63 vm_object_t object; 64 65 /* 66 * Offset should be page aligned. 67 */ 68 if (foff & PAGE_MASK) 69 return (NULL); 70 71 size = round_page(size); 72 73 if (handle != NULL) { 74 /* 75 * Lock to prevent object creation race condition. 76 */ 77 while (phys_pager_alloc_lock) { 78 phys_pager_alloc_lock = -1; 79 msleep(&phys_pager_alloc_lock, &vm_mtx, PVM, "swpalc", 0); 80 } 81 phys_pager_alloc_lock = 1; 82 83 /* 84 * Look up pager, creating as necessary. 85 */ 86 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 87 if (object == NULL) { 88 /* 89 * Allocate object and associate it with the pager. 90 */ 91 object = vm_object_allocate(OBJT_PHYS, 92 OFF_TO_IDX(foff + size)); 93 object->handle = handle; 94 mtx_lock(&phys_pager_mtx); 95 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 96 pager_object_list); 97 mtx_unlock(&phys_pager_mtx); 98 } else { 99 /* 100 * Gain a reference to the object. 101 */ 102 vm_object_reference(object); 103 if (OFF_TO_IDX(foff + size) > object->size) 104 object->size = OFF_TO_IDX(foff + size); 105 } 106 if (phys_pager_alloc_lock == -1) 107 wakeup(&phys_pager_alloc_lock); 108 phys_pager_alloc_lock = 0; 109 110 } else { 111 object = vm_object_allocate(OBJT_PHYS, 112 OFF_TO_IDX(foff + size)); 113 } 114 115 return (object); 116 } 117 118 static void 119 phys_pager_dealloc(vm_object_t object) 120 { 121 122 if (object->handle != NULL) { 123 mtx_lock(&phys_pager_mtx); 124 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 125 mtx_unlock(&phys_pager_mtx); 126 } 127 } 128 129 static int 130 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 131 { 132 int i, s; 133 134 s = splvm(); 135 /* 136 * Fill as many pages as vm_fault has allocated for us. 137 */ 138 for (i = 0; i < count; i++) { 139 if ((m[i]->flags & PG_ZERO) == 0) 140 vm_page_zero_fill(m[i]); 141 vm_page_flag_set(m[i], PG_ZERO); 142 /* Switch off pv_entries */ 143 vm_page_unmanage(m[i]); 144 m[i]->valid = VM_PAGE_BITS_ALL; 145 m[i]->dirty = 0; 146 /* The requested page must remain busy, the others not. */ 147 if (reqpage != i) { 148 vm_page_flag_clear(m[i], PG_BUSY); 149 m[i]->busy = 0; 150 } 151 } 152 splx(s); 153 154 return (VM_PAGER_OK); 155 } 156 157 static void 158 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 159 int *rtvals) 160 { 161 162 panic("phys_pager_putpage called"); 163 } 164 165 /* 166 * Implement a pretty aggressive clustered getpages strategy. Hint that 167 * everything in an entire 4MB window should be prefaulted at once. 168 * 169 * XXX 4MB (1024 slots per page table page) is convenient for x86, 170 * but may not be for other arches. 171 */ 172 #ifndef PHYSCLUSTER 173 #define PHYSCLUSTER 1024 174 #endif 175 static boolean_t 176 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 177 int *after) 178 { 179 vm_pindex_t base, end; 180 181 base = pindex & (~(PHYSCLUSTER - 1)); 182 end = base + (PHYSCLUSTER - 1); 183 if (before != NULL) 184 *before = pindex - base; 185 if (after != NULL) 186 *after = end - pindex; 187 return (TRUE); 188 } 189 190 struct pagerops physpagerops = { 191 phys_pager_init, 192 phys_pager_alloc, 193 phys_pager_dealloc, 194 phys_pager_getpages, 195 phys_pager_putpages, 196 phys_pager_haspage, 197 NULL 198 }; 199