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/proc.h> 35 #include <sys/mutex.h> 36 #include <sys/mman.h> 37 #include <sys/sysctl.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 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 GIANT_REQUIRED; 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 while (phys_pager_alloc_lock) { 80 phys_pager_alloc_lock = -1; 81 tsleep(&phys_pager_alloc_lock, PVM, "swpalc", 0); 82 } 83 phys_pager_alloc_lock = 1; 84 85 /* 86 * Look up pager, creating as necessary. 87 */ 88 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 89 if (object == NULL) { 90 /* 91 * Allocate object and associate it with the pager. 92 */ 93 object = vm_object_allocate(OBJT_PHYS, 94 OFF_TO_IDX(foff + size)); 95 object->handle = handle; 96 mtx_lock(&phys_pager_mtx); 97 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 98 pager_object_list); 99 mtx_unlock(&phys_pager_mtx); 100 } else { 101 /* 102 * Gain a reference to the object. 103 */ 104 vm_object_reference(object); 105 if (OFF_TO_IDX(foff + size) > object->size) 106 object->size = OFF_TO_IDX(foff + size); 107 } 108 if (phys_pager_alloc_lock == -1) 109 wakeup(&phys_pager_alloc_lock); 110 phys_pager_alloc_lock = 0; 111 112 } else { 113 object = vm_object_allocate(OBJT_PHYS, 114 OFF_TO_IDX(foff + size)); 115 } 116 117 return (object); 118 } 119 120 static void 121 phys_pager_dealloc(vm_object_t object) 122 { 123 124 if (object->handle != NULL) { 125 mtx_lock(&phys_pager_mtx); 126 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 127 mtx_unlock(&phys_pager_mtx); 128 } 129 } 130 131 static int 132 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 133 { 134 int i, s; 135 136 s = splvm(); 137 /* 138 * Fill as many pages as vm_fault has allocated for us. 139 */ 140 for (i = 0; i < count; i++) { 141 if ((m[i]->flags & PG_ZERO) == 0) 142 vm_page_zero_fill(m[i]); 143 vm_page_flag_set(m[i], PG_ZERO); 144 /* Switch off pv_entries */ 145 vm_page_unmanage(m[i]); 146 m[i]->valid = VM_PAGE_BITS_ALL; 147 m[i]->dirty = 0; 148 /* The requested page must remain busy, the others not. */ 149 if (reqpage != i) { 150 vm_page_flag_clear(m[i], PG_BUSY); 151 m[i]->busy = 0; 152 } 153 } 154 splx(s); 155 156 return (VM_PAGER_OK); 157 } 158 159 static void 160 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 161 int *rtvals) 162 { 163 164 panic("phys_pager_putpage called"); 165 } 166 167 /* 168 * Implement a pretty aggressive clustered getpages strategy. Hint that 169 * everything in an entire 4MB window should be prefaulted at once. 170 * 171 * XXX 4MB (1024 slots per page table page) is convenient for x86, 172 * but may not be for other arches. 173 */ 174 #ifndef PHYSCLUSTER 175 #define PHYSCLUSTER 1024 176 #endif 177 static boolean_t 178 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 179 int *after) 180 { 181 vm_pindex_t base, end; 182 183 base = pindex & (~(PHYSCLUSTER - 1)); 184 end = base + (PHYSCLUSTER - 1); 185 if (before != NULL) 186 *before = pindex - base; 187 if (after != NULL) 188 *after = end - pindex; 189 return (TRUE); 190 } 191 192 struct pagerops physpagerops = { 193 phys_pager_init, 194 phys_pager_alloc, 195 phys_pager_dealloc, 196 phys_pager_getpages, 197 phys_pager_putpages, 198 phys_pager_haspage, 199 NULL 200 }; 201