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/mman.h> 33 #include <sys/sysctl.h> 34 35 #include <vm/vm.h> 36 #include <vm/vm_object.h> 37 #include <vm/vm_page.h> 38 #include <vm/vm_pager.h> 39 #include <vm/vm_zone.h> 40 41 /* list of device pager objects */ 42 static struct pagerlst phys_pager_object_list; 43 44 static int phys_pager_alloc_lock, phys_pager_alloc_lock_want; 45 46 static void 47 phys_pager_init(void) 48 { 49 50 TAILQ_INIT(&phys_pager_object_list); 51 } 52 53 static vm_object_t 54 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 55 vm_ooffset_t foff) 56 { 57 vm_object_t object; 58 59 /* 60 * Offset should be page aligned. 61 */ 62 if (foff & PAGE_MASK) 63 return (NULL); 64 65 size = round_page(size); 66 67 /* 68 * Lock to prevent object creation race condition. 69 */ 70 while (phys_pager_alloc_lock) { 71 phys_pager_alloc_lock_want++; 72 tsleep(&phys_pager_alloc_lock, PVM, "ppall", 0); 73 phys_pager_alloc_lock_want--; 74 } 75 phys_pager_alloc_lock = 1; 76 77 /* 78 * Look up pager, creating as necessary. 79 */ 80 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 81 if (object == NULL) { 82 /* 83 * Allocate object and associate it with the pager. 84 */ 85 object = vm_object_allocate(OBJT_PHYS, 86 OFF_TO_IDX(foff + size)); 87 object->handle = handle; 88 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 89 pager_object_list); 90 } else { 91 /* 92 * Gain a reference to the object. 93 */ 94 vm_object_reference(object); 95 if (OFF_TO_IDX(foff + size) > object->size) 96 object->size = OFF_TO_IDX(foff + size); 97 } 98 99 phys_pager_alloc_lock = 0; 100 if (phys_pager_alloc_lock_want) 101 wakeup(&phys_pager_alloc_lock); 102 103 return (object); 104 } 105 106 static void 107 phys_pager_dealloc(vm_object_t object) 108 { 109 110 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 111 } 112 113 static int 114 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 115 { 116 int i, s; 117 118 s = splvm(); 119 /* 120 * Fill as many pages as vm_fault has allocated for us. 121 */ 122 for (i = 0; i < count; i++) { 123 if ((m[i]->flags & PG_ZERO) == 0) 124 vm_page_zero_fill(m[i]); 125 vm_page_flag_set(m[i], PG_ZERO); 126 /* Switch off pv_entries */ 127 vm_page_unmanage(m[i]); 128 m[i]->valid = VM_PAGE_BITS_ALL; 129 m[i]->dirty = 0; 130 /* The requested page must remain busy, the others not. */ 131 if (reqpage != i) { 132 vm_page_flag_clear(m[i], PG_BUSY); 133 m[i]->busy = 0; 134 } 135 } 136 splx(s); 137 138 return (VM_PAGER_OK); 139 } 140 141 static void 142 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 143 int *rtvals) 144 { 145 146 panic("phys_pager_putpage called"); 147 } 148 149 /* 150 * Implement a pretty aggressive clustered getpages strategy. Hint that 151 * everything in an entire 4MB window should be prefaulted at once. 152 * 153 * XXX 4MB (1024 slots per page table page) is convenient for x86, 154 * but may not be for other arches. 155 */ 156 #ifndef PHYSCLUSTER 157 #define PHYSCLUSTER 1024 158 #endif 159 static boolean_t 160 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 161 int *after) 162 { 163 vm_pindex_t base, end; 164 165 base = pindex & (~(PHYSCLUSTER - 1)); 166 end = base + (PHYSCLUSTER - 1); 167 if (before != NULL) 168 *before = pindex - base; 169 if (after != NULL) 170 *after = end - pindex; 171 return (TRUE); 172 } 173 174 struct pagerops physpagerops = { 175 phys_pager_init, 176 phys_pager_alloc, 177 phys_pager_dealloc, 178 phys_pager_getpages, 179 phys_pager_putpages, 180 phys_pager_haspage, 181 NULL 182 }; 183