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/uma.h> 46 47 static vm_object_t sg_pager_alloc(void *, vm_ooffset_t, vm_prot_t, 48 vm_ooffset_t, struct ucred *); 49 static void sg_pager_dealloc(vm_object_t); 50 static int sg_pager_getpages(vm_object_t, vm_page_t *, int, int); 51 static void sg_pager_putpages(vm_object_t, vm_page_t *, int, 52 boolean_t, int *); 53 static boolean_t sg_pager_haspage(vm_object_t, vm_pindex_t, int *, 54 int *); 55 56 struct pagerops sgpagerops = { 57 .pgo_alloc = sg_pager_alloc, 58 .pgo_dealloc = sg_pager_dealloc, 59 .pgo_getpages = sg_pager_getpages, 60 .pgo_putpages = sg_pager_putpages, 61 .pgo_haspage = sg_pager_haspage, 62 }; 63 64 static vm_object_t 65 sg_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 66 vm_ooffset_t foff, struct ucred *cred) 67 { 68 struct sglist *sg; 69 vm_object_t object; 70 vm_pindex_t npages, pindex; 71 int i; 72 73 /* 74 * Offset should be page aligned. 75 */ 76 if (foff & PAGE_MASK) 77 return (NULL); 78 79 /* 80 * The scatter/gather list must only include page-aligned 81 * ranges. 82 */ 83 npages = 0; 84 sg = handle; 85 for (i = 0; i < sg->sg_nseg; i++) { 86 if ((sg->sg_segs[i].ss_paddr % PAGE_SIZE) != 0 || 87 (sg->sg_segs[i].ss_len % PAGE_SIZE) != 0) 88 return (NULL); 89 npages += sg->sg_segs[i].ss_len / PAGE_SIZE; 90 } 91 92 /* 93 * The scatter/gather list has a fixed size. Refuse requests 94 * to map beyond that. 95 */ 96 size = round_page(size); 97 pindex = OFF_TO_IDX(foff + size); 98 if (pindex > npages) 99 return (NULL); 100 101 /* 102 * Allocate a new object and associate it with the 103 * scatter/gather list. It is ok for our purposes to have 104 * multiple VM objects associated with the same scatter/gather 105 * list because scatter/gather lists are static. This is also 106 * simpler than ensuring a unique object per scatter/gather 107 * list. 108 */ 109 object = vm_object_allocate(OBJT_SG, npages); 110 object->handle = sglist_hold(sg); 111 TAILQ_INIT(&object->un_pager.sgp.sgp_pglist); 112 return (object); 113 } 114 115 static void 116 sg_pager_dealloc(vm_object_t object) 117 { 118 struct sglist *sg; 119 vm_page_t m; 120 121 /* 122 * Free up our fake pages. 123 */ 124 while ((m = TAILQ_FIRST(&object->un_pager.sgp.sgp_pglist)) != 0) { 125 TAILQ_REMOVE(&object->un_pager.sgp.sgp_pglist, m, pageq); 126 vm_page_putfake(m); 127 } 128 129 sg = object->handle; 130 sglist_free(sg); 131 } 132 133 static int 134 sg_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 135 { 136 struct sglist *sg; 137 vm_page_t m_paddr, page; 138 vm_pindex_t offset; 139 vm_paddr_t paddr; 140 vm_memattr_t memattr; 141 size_t space; 142 int i; 143 144 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 145 sg = object->handle; 146 memattr = object->memattr; 147 VM_OBJECT_UNLOCK(object); 148 offset = m[reqpage]->pindex; 149 150 /* 151 * Lookup the physical address of the requested page. An initial 152 * value of '1' instead of '0' is used so we can assert that the 153 * page is found since '0' can be a valid page-aligned physical 154 * address. 155 */ 156 space = 0; 157 paddr = 1; 158 for (i = 0; i < sg->sg_nseg; i++) { 159 if (space + sg->sg_segs[i].ss_len <= (offset * PAGE_SIZE)) { 160 space += sg->sg_segs[i].ss_len; 161 continue; 162 } 163 paddr = sg->sg_segs[i].ss_paddr + offset * PAGE_SIZE - space; 164 break; 165 } 166 KASSERT(paddr != 1, ("invalid SG page index")); 167 168 /* If "paddr" is a real page, perform a sanity check on "memattr". */ 169 if ((m_paddr = vm_phys_paddr_to_vm_page(paddr)) != NULL && 170 pmap_page_get_memattr(m_paddr) != memattr) { 171 memattr = pmap_page_get_memattr(m_paddr); 172 printf( 173 "WARNING: A device driver has set \"memattr\" inconsistently.\n"); 174 } 175 176 /* Return a fake page for the requested page. */ 177 KASSERT(!(m[reqpage]->flags & PG_FICTITIOUS), 178 ("backing page for SG is fake")); 179 180 /* Construct a new fake page. */ 181 page = vm_page_getfake(paddr, memattr); 182 VM_OBJECT_LOCK(object); 183 TAILQ_INSERT_TAIL(&object->un_pager.sgp.sgp_pglist, page, pageq); 184 185 /* Free the original pages and insert this fake page into the object. */ 186 for (i = 0; i < count; i++) { 187 vm_page_lock(m[i]); 188 vm_page_free(m[i]); 189 vm_page_unlock(m[i]); 190 } 191 vm_page_insert(page, object, offset); 192 m[reqpage] = page; 193 page->valid = VM_PAGE_BITS_ALL; 194 195 return (VM_PAGER_OK); 196 } 197 198 static void 199 sg_pager_putpages(vm_object_t object, vm_page_t *m, int count, 200 boolean_t sync, int *rtvals) 201 { 202 203 panic("sg_pager_putpage called"); 204 } 205 206 static boolean_t 207 sg_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 208 int *after) 209 { 210 211 if (before != NULL) 212 *before = 0; 213 if (after != NULL) 214 *after = 0; 215 return (TRUE); 216 } 217