1 /*- 2 * Copyright (c) 2009 Advanced Computing Technologies LLC 3 * Written by: John H. Baldwin <jhb@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 /* 32 * This pager manages OBJT_SG objects. These objects are backed by 33 * a scatter/gather list of physical address ranges. 34 */ 35 36 #include <sys/param.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/sglist.h> 40 #include <vm/vm.h> 41 #include <vm/vm_param.h> 42 #include <vm/vm_object.h> 43 #include <vm/vm_page.h> 44 #include <vm/vm_pager.h> 45 #include <vm/vm_phys.h> 46 #include <vm/uma.h> 47 48 static vm_object_t sg_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 49 vm_ooffset_t, struct ucred *); 50 static void sg_pager_dealloc(vm_object_t); 51 static int sg_pager_getpages(vm_object_t, vm_page_t *, int, int); 52 static void sg_pager_putpages(vm_object_t, vm_page_t *, int, 53 boolean_t, int *); 54 static boolean_t sg_pager_haspage(vm_object_t, vm_pindex_t, int *, 55 int *); 56 57 struct pagerops sgpagerops = { 58 .pgo_alloc = sg_pager_alloc, 59 .pgo_dealloc = sg_pager_dealloc, 60 .pgo_getpages = sg_pager_getpages, 61 .pgo_putpages = sg_pager_putpages, 62 .pgo_haspage = sg_pager_haspage, 63 }; 64 65 static vm_object_t 66 sg_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 67 vm_ooffset_t foff, struct ucred *cred) 68 { 69 struct sglist *sg; 70 vm_object_t object; 71 vm_pindex_t npages, pindex; 72 int i; 73 74 /* 75 * Offset should be page aligned. 76 */ 77 if (foff & PAGE_MASK) 78 return (NULL); 79 80 /* 81 * The scatter/gather list must only include page-aligned 82 * ranges. 83 */ 84 npages = 0; 85 sg = handle; 86 for (i = 0; i < sg->sg_nseg; i++) { 87 if ((sg->sg_segs[i].ss_paddr % PAGE_SIZE) != 0 || 88 (sg->sg_segs[i].ss_len % PAGE_SIZE) != 0) 89 return (NULL); 90 npages += sg->sg_segs[i].ss_len / PAGE_SIZE; 91 } 92 93 /* 94 * The scatter/gather list has a fixed size. Refuse requests 95 * to map beyond that. 96 */ 97 size = round_page(size); 98 pindex = OFF_TO_IDX(foff + size); 99 if (pindex > npages) 100 return (NULL); 101 102 /* 103 * Allocate a new object and associate it with the 104 * scatter/gather list. It is ok for our purposes to have 105 * multiple VM objects associated with the same scatter/gather 106 * list because scatter/gather lists are static. This is also 107 * simpler than ensuring a unique object per scatter/gather 108 * list. 109 */ 110 object = vm_object_allocate(OBJT_SG, npages); 111 object->handle = sglist_hold(sg); 112 TAILQ_INIT(&object->un_pager.sgp.sgp_pglist); 113 return (object); 114 } 115 116 static void 117 sg_pager_dealloc(vm_object_t object) 118 { 119 struct sglist *sg; 120 vm_page_t m; 121 122 /* 123 * Free up our fake pages. 124 */ 125 while ((m = TAILQ_FIRST(&object->un_pager.sgp.sgp_pglist)) != 0) { 126 TAILQ_REMOVE(&object->un_pager.sgp.sgp_pglist, m, pageq); 127 vm_page_putfake(m); 128 } 129 130 sg = object->handle; 131 sglist_free(sg); 132 } 133 134 static int 135 sg_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 136 { 137 struct sglist *sg; 138 vm_page_t m_paddr, page; 139 vm_pindex_t offset; 140 vm_paddr_t paddr; 141 vm_memattr_t memattr; 142 size_t space; 143 int i; 144 145 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 146 sg = object->handle; 147 memattr = object->memattr; 148 VM_OBJECT_UNLOCK(object); 149 offset = m[reqpage]->pindex; 150 151 /* 152 * Lookup the physical address of the requested page. An initial 153 * value of '1' instead of '0' is used so we can assert that the 154 * page is found since '0' can be a valid page-aligned physical 155 * address. 156 */ 157 space = 0; 158 paddr = 1; 159 for (i = 0; i < sg->sg_nseg; i++) { 160 if (space + sg->sg_segs[i].ss_len <= (offset * PAGE_SIZE)) { 161 space += sg->sg_segs[i].ss_len; 162 continue; 163 } 164 paddr = sg->sg_segs[i].ss_paddr + offset * PAGE_SIZE - space; 165 break; 166 } 167 KASSERT(paddr != 1, ("invalid SG page index")); 168 169 /* If "paddr" is a real page, perform a sanity check on "memattr". */ 170 if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL && 171 pmap_page_get_memattr(m_paddr) != memattr) { 172 memattr = pmap_page_get_memattr(m_paddr); 173 printf( 174 "WARNING: A device driver has set \"memattr\" inconsistently.\n"); 175 } 176 177 /* Return a fake page for the requested page. */ 178 KASSERT(!(m[reqpage]->flags & PG_FICTITIOUS), 179 ("backing page for SG is fake")); 180 181 /* Construct a new fake page. */ 182 page = vm_page_getfake(paddr, memattr); 183 VM_OBJECT_LOCK(object); 184 TAILQ_INSERT_TAIL(&object->un_pager.sgp.sgp_pglist, page, pageq); 185 186 /* Free the original pages and insert this fake page into the object. */ 187 for (i = 0; i < count; i++) { 188 vm_page_lock(m[i]); 189 vm_page_free(m[i]); 190 vm_page_unlock(m[i]); 191 } 192 vm_page_insert(page, object, offset); 193 m[reqpage] = page; 194 page->valid = VM_PAGE_BITS_ALL; 195 196 return (VM_PAGER_OK); 197 } 198 199 static void 200 sg_pager_putpages(vm_object_t object, vm_page_t *m, int count, 201 boolean_t sync, int *rtvals) 202 { 203 204 panic("sg_pager_putpage called"); 205 } 206 207 static boolean_t 208 sg_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 209 int *after) 210 { 211 212 if (before != NULL) 213 *before = 0; 214 if (after != NULL) 215 *after = 0; 216 return (TRUE); 217 } 218