1 /* $OpenBSD: uvm_device.c,v 1.57 2019/12/08 12:37:45 mpi Exp $ */ 2 /* $NetBSD: uvm_device.c,v 1.30 2000/11/25 06:27:59 chs Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp 29 */ 30 31 /* 32 * uvm_device.c: the device pager. 33 */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/conf.h> 38 #include <sys/malloc.h> 39 #include <sys/mutex.h> 40 41 #include <uvm/uvm.h> 42 #include <uvm/uvm_device.h> 43 44 #if defined(__amd64__) || defined(__arm64__) || \ 45 defined(__i386__) || defined(__loongson__) || \ 46 defined(__macppc__) || defined(__sparc64__) 47 #include "drm.h" 48 #endif 49 50 /* 51 * private global data structure 52 * 53 * we keep a list of active device objects in the system. 54 */ 55 56 LIST_HEAD(, uvm_device) udv_list = LIST_HEAD_INITIALIZER(udv_list); 57 struct mutex udv_lock = MUTEX_INITIALIZER(IPL_NONE); 58 59 /* 60 * functions 61 */ 62 static void udv_reference(struct uvm_object *); 63 static void udv_detach(struct uvm_object *); 64 static int udv_fault(struct uvm_faultinfo *, vaddr_t, 65 vm_page_t *, int, int, vm_fault_t, 66 vm_prot_t, int); 67 static boolean_t udv_flush(struct uvm_object *, voff_t, voff_t, 68 int); 69 70 /* 71 * master pager structure 72 */ 73 struct uvm_pagerops uvm_deviceops = { 74 NULL, /* inited statically */ 75 udv_reference, 76 udv_detach, 77 udv_fault, 78 udv_flush, 79 }; 80 81 /* 82 * udv_attach 83 * 84 * get a VM object that is associated with a device. allocate a new 85 * one if needed. 86 * 87 * => nothing should be locked so that we can sleep here. 88 * 89 * The last two arguments (off and size) are only used for access checking. 90 */ 91 struct uvm_object * 92 udv_attach(dev_t device, vm_prot_t accessprot, voff_t off, vsize_t size) 93 { 94 struct uvm_device *udv, *lcv; 95 paddr_t (*mapfn)(dev_t, off_t, int); 96 #if NDRM > 0 97 struct uvm_object *obj; 98 #endif 99 100 /* before we do anything, ensure this device supports mmap */ 101 mapfn = cdevsw[major(device)].d_mmap; 102 if (mapfn == NULL || 103 mapfn == (paddr_t (*)(dev_t, off_t, int)) enodev || 104 mapfn == (paddr_t (*)(dev_t, off_t, int)) nullop) 105 return(NULL); 106 107 /* Negative offsets on the object are not allowed. */ 108 if (off < 0) 109 return(NULL); 110 111 #if NDRM > 0 112 obj = udv_attach_drm(device, accessprot, off, size); 113 if (obj) 114 return(obj); 115 #endif 116 117 /* 118 * Check that the specified range of the device allows the 119 * desired protection. 120 * 121 * XXX clobbers off and size, but nothing else here needs them. 122 */ 123 while (size != 0) { 124 if ((*mapfn)(device, off, accessprot) == -1) 125 return (NULL); 126 off += PAGE_SIZE; size -= PAGE_SIZE; 127 } 128 129 /* keep looping until we get it */ 130 for (;;) { 131 /* first, attempt to find it on the main list */ 132 mtx_enter(&udv_lock); 133 LIST_FOREACH(lcv, &udv_list, u_list) { 134 if (device == lcv->u_device) 135 break; 136 } 137 138 /* got it on main list. put a hold on it and unlock udv_lock. */ 139 if (lcv) { 140 /* 141 * if someone else has a hold on it, sleep and start 142 * over again. Else, we need take HOLD flag so we 143 * don't have to re-order locking here. 144 */ 145 if (lcv->u_flags & UVM_DEVICE_HOLD) { 146 lcv->u_flags |= UVM_DEVICE_WANTED; 147 msleep_nsec(lcv, &udv_lock, PVM | PNORELOCK, 148 "udv_attach", INFSLP); 149 continue; 150 } 151 152 /* we are now holding it */ 153 lcv->u_flags |= UVM_DEVICE_HOLD; 154 mtx_leave(&udv_lock); 155 156 /* bump reference count, unhold, return. */ 157 lcv->u_obj.uo_refs++; 158 159 mtx_enter(&udv_lock); 160 if (lcv->u_flags & UVM_DEVICE_WANTED) 161 wakeup(lcv); 162 lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); 163 mtx_leave(&udv_lock); 164 return(&lcv->u_obj); 165 } 166 167 /* did not find it on main list. need to malloc a new one. */ 168 mtx_leave(&udv_lock); 169 /* NOTE: we could sleep in the following malloc() */ 170 udv = malloc(sizeof(*udv), M_TEMP, M_WAITOK); 171 mtx_enter(&udv_lock); 172 173 /* 174 * now we have to double check to make sure no one added it 175 * to the list while we were sleeping... 176 */ 177 LIST_FOREACH(lcv, &udv_list, u_list) { 178 if (device == lcv->u_device) 179 break; 180 } 181 182 /* 183 * did we lose a race to someone else? 184 * free our memory and retry. 185 */ 186 if (lcv) { 187 mtx_leave(&udv_lock); 188 free(udv, M_TEMP, sizeof(*udv)); 189 continue; 190 } 191 192 /* 193 * we have it! init the data structures, add to list 194 * and return. 195 */ 196 uvm_objinit(&udv->u_obj, &uvm_deviceops, 1); 197 udv->u_flags = 0; 198 udv->u_device = device; 199 LIST_INSERT_HEAD(&udv_list, udv, u_list); 200 mtx_leave(&udv_lock); 201 return(&udv->u_obj); 202 } 203 /*NOTREACHED*/ 204 } 205 206 /* 207 * udv_reference 208 * 209 * add a reference to a VM object. Note that the reference count must 210 * already be one (the passed in reference) so there is no chance of the 211 * udv being released or locked out here. 212 */ 213 static void 214 udv_reference(struct uvm_object *uobj) 215 { 216 217 uobj->uo_refs++; 218 } 219 220 /* 221 * udv_detach 222 * 223 * remove a reference to a VM object. 224 */ 225 static void 226 udv_detach(struct uvm_object *uobj) 227 { 228 struct uvm_device *udv = (struct uvm_device *)uobj; 229 230 /* loop until done */ 231 again: 232 if (uobj->uo_refs > 1) { 233 uobj->uo_refs--; 234 return; 235 } 236 KASSERT(uobj->uo_npages == 0 && RBT_EMPTY(uvm_objtree, &uobj->memt)); 237 238 /* is it being held? if so, wait until others are done. */ 239 mtx_enter(&udv_lock); 240 if (udv->u_flags & UVM_DEVICE_HOLD) { 241 udv->u_flags |= UVM_DEVICE_WANTED; 242 /* 243 * lock interleaving. -- this is ok in this case since the 244 * locks are both IPL_NONE 245 */ 246 msleep_nsec(udv, &udv_lock, PVM | PNORELOCK, "udv_detach", 247 INFSLP); 248 goto again; 249 } 250 251 /* got it! nuke it now. */ 252 LIST_REMOVE(udv, u_list); 253 if (udv->u_flags & UVM_DEVICE_WANTED) 254 wakeup(udv); 255 mtx_leave(&udv_lock); 256 free(udv, M_TEMP, sizeof(*udv)); 257 } 258 259 260 /* 261 * udv_flush 262 * 263 * flush pages out of a uvm object. a no-op for devices. 264 */ 265 static boolean_t 266 udv_flush(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 267 { 268 269 return(TRUE); 270 } 271 272 /* 273 * udv_fault: non-standard fault routine for device "pages" 274 * 275 * => rather than having a "get" function, we have a fault routine 276 * since we don't return vm_pages we need full control over the 277 * pmap_enter map in 278 * => on return, we unlock all fault data structures 279 * => flags: PGO_ALLPAGES: get all of the pages 280 * PGO_LOCKED: fault data structures are locked 281 * XXX: currently PGO_LOCKED is always required ... consider removing 282 * it as a flag 283 * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] 284 */ 285 static int 286 udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, vm_page_t *pps, int npages, 287 int centeridx, vm_fault_t fault_type, vm_prot_t access_type, int flags) 288 { 289 struct vm_map_entry *entry = ufi->entry; 290 struct uvm_object *uobj = entry->object.uvm_obj; 291 struct uvm_device *udv = (struct uvm_device *)uobj; 292 vaddr_t curr_va; 293 off_t curr_offset; 294 paddr_t paddr; 295 int lcv, retval; 296 dev_t device; 297 paddr_t (*mapfn)(dev_t, off_t, int); 298 vm_prot_t mapprot; 299 300 /* 301 * we do not allow device mappings to be mapped copy-on-write 302 * so we kill any attempt to do so here. 303 */ 304 if (UVM_ET_ISCOPYONWRITE(entry)) { 305 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 306 return(VM_PAGER_ERROR); 307 } 308 309 /* get device map function. */ 310 device = udv->u_device; 311 mapfn = cdevsw[major(device)].d_mmap; 312 313 /* 314 * now we must determine the offset in udv to use and the VA to 315 * use for pmap_enter. note that we always use orig_map's pmap 316 * for pmap_enter (even if we have a submap). since virtual 317 * addresses in a submap must match the main map, this is ok. 318 */ 319 /* udv offset = (offset from start of entry) + entry's offset */ 320 curr_offset = entry->offset + (vaddr - entry->start); 321 /* pmap va = vaddr (virtual address of pps[0]) */ 322 curr_va = vaddr; 323 324 /* loop over the page range entering in as needed */ 325 retval = VM_PAGER_OK; 326 for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, 327 curr_va += PAGE_SIZE) { 328 if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) 329 continue; 330 331 if (pps[lcv] == PGO_DONTCARE) 332 continue; 333 334 paddr = (*mapfn)(device, curr_offset, access_type); 335 if (paddr == -1) { 336 retval = VM_PAGER_ERROR; 337 break; 338 } 339 mapprot = ufi->entry->protection; 340 if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, 341 mapprot, PMAP_CANFAIL | mapprot) != 0) { 342 /* 343 * pmap_enter() didn't have the resource to 344 * enter this mapping. Unlock everything, 345 * wait for the pagedaemon to free up some 346 * pages, and then tell uvm_fault() to start 347 * the fault again. 348 * 349 * XXX Needs some rethinking for the PGO_ALLPAGES 350 * XXX case. 351 */ 352 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, 353 uobj, NULL); 354 355 /* sync what we have so far */ 356 pmap_update(ufi->orig_map->pmap); 357 uvm_wait("udv_fault"); 358 return (VM_PAGER_REFAULT); 359 } 360 } 361 362 uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj, NULL); 363 pmap_update(ufi->orig_map->pmap); 364 return (retval); 365 } 366