1 | /* $NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 1997 Charles D. Cranor and Washington University. |
5 | * All rights reserved. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * |
27 | * from: Id: uvm_device.c,v 1.1.2.9 1998/02/06 05:11:47 chs Exp |
28 | */ |
29 | |
30 | /* |
31 | * uvm_device.c: the device pager. |
32 | */ |
33 | |
34 | #include <sys/cdefs.h> |
35 | __KERNEL_RCSID(0, "$NetBSD: uvm_device.c,v 1.64 2014/12/14 23:48:58 chs Exp $" ); |
36 | |
37 | #include "opt_uvmhist.h" |
38 | |
39 | #include <sys/param.h> |
40 | #include <sys/systm.h> |
41 | #include <sys/conf.h> |
42 | #include <sys/proc.h> |
43 | #include <sys/kmem.h> |
44 | |
45 | #include <uvm/uvm.h> |
46 | #include <uvm/uvm_device.h> |
47 | #include <uvm/uvm_pmap.h> |
48 | |
49 | /* |
50 | * private global data structure |
51 | * |
52 | * we keep a list of active device objects in the system. |
53 | */ |
54 | |
55 | LIST_HEAD(udv_list_struct, uvm_device); |
56 | static struct udv_list_struct udv_list; |
57 | static kmutex_t udv_lock; |
58 | |
59 | /* |
60 | * functions |
61 | */ |
62 | |
63 | static void udv_init(void); |
64 | static void udv_reference(struct uvm_object *); |
65 | static void udv_detach(struct uvm_object *); |
66 | static int udv_fault(struct uvm_faultinfo *, vaddr_t, |
67 | struct vm_page **, int, int, vm_prot_t, |
68 | int); |
69 | |
70 | /* |
71 | * master pager structure |
72 | */ |
73 | |
74 | const struct uvm_pagerops uvm_deviceops = { |
75 | .pgo_init = udv_init, |
76 | .pgo_reference = udv_reference, |
77 | .pgo_detach = udv_detach, |
78 | .pgo_fault = udv_fault, |
79 | }; |
80 | |
81 | /* |
82 | * the ops! |
83 | */ |
84 | |
85 | /* |
86 | * udv_init |
87 | * |
88 | * init pager private data structures. |
89 | */ |
90 | |
91 | static void |
92 | udv_init(void) |
93 | { |
94 | LIST_INIT(&udv_list); |
95 | mutex_init(&udv_lock, MUTEX_DEFAULT, IPL_NONE); |
96 | } |
97 | |
98 | /* |
99 | * udv_attach |
100 | * |
101 | * get a VM object that is associated with a device. allocate a new |
102 | * one if needed. |
103 | * |
104 | * => caller must _not_ already be holding the lock on the uvm_object. |
105 | * => in fact, nothing should be locked so that we can sleep here. |
106 | */ |
107 | |
108 | struct uvm_object * |
109 | udv_attach(dev_t device, vm_prot_t accessprot, |
110 | voff_t off, /* used only for access check */ |
111 | vsize_t size /* used only for access check */) |
112 | { |
113 | struct uvm_device *udv, *lcv; |
114 | const struct cdevsw *cdev; |
115 | dev_type_mmap((*mapfn)); |
116 | |
117 | UVMHIST_FUNC("udv_attach" ); UVMHIST_CALLED(maphist); |
118 | |
119 | UVMHIST_LOG(maphist, "(device=0x%x)" , device,0,0,0); |
120 | |
121 | /* |
122 | * before we do anything, ensure this device supports mmap |
123 | */ |
124 | |
125 | cdev = cdevsw_lookup(device); |
126 | if (cdev == NULL) { |
127 | return (NULL); |
128 | } |
129 | mapfn = cdev->d_mmap; |
130 | if (mapfn == NULL || mapfn == nommap || mapfn == nullmmap) { |
131 | return(NULL); |
132 | } |
133 | |
134 | /* |
135 | * Negative offsets on the object are not allowed. |
136 | */ |
137 | |
138 | if ((cdev->d_flag & D_NEGOFFSAFE) == 0 && |
139 | off != UVM_UNKNOWN_OFFSET && off < 0) |
140 | return(NULL); |
141 | |
142 | /* |
143 | * Check that the specified range of the device allows the |
144 | * desired protection. |
145 | * |
146 | * XXX assumes VM_PROT_* == PROT_* |
147 | * XXX clobbers off and size, but nothing else here needs them. |
148 | */ |
149 | |
150 | while (size != 0) { |
151 | if (cdev_mmap(device, off, accessprot) == -1) { |
152 | return (NULL); |
153 | } |
154 | off += PAGE_SIZE; size -= PAGE_SIZE; |
155 | } |
156 | |
157 | /* |
158 | * keep looping until we get it |
159 | */ |
160 | |
161 | for (;;) { |
162 | |
163 | /* |
164 | * first, attempt to find it on the main list |
165 | */ |
166 | |
167 | mutex_enter(&udv_lock); |
168 | LIST_FOREACH(lcv, &udv_list, u_list) { |
169 | if (device == lcv->u_device) |
170 | break; |
171 | } |
172 | |
173 | /* |
174 | * got it on main list. put a hold on it and unlock udv_lock. |
175 | */ |
176 | |
177 | if (lcv) { |
178 | |
179 | /* |
180 | * if someone else has a hold on it, sleep and start |
181 | * over again. |
182 | */ |
183 | |
184 | if (lcv->u_flags & UVM_DEVICE_HOLD) { |
185 | lcv->u_flags |= UVM_DEVICE_WANTED; |
186 | UVM_UNLOCK_AND_WAIT(lcv, &udv_lock, false, |
187 | "udv_attach" ,0); |
188 | continue; |
189 | } |
190 | |
191 | /* we are now holding it */ |
192 | lcv->u_flags |= UVM_DEVICE_HOLD; |
193 | mutex_exit(&udv_lock); |
194 | |
195 | /* |
196 | * bump reference count, unhold, return. |
197 | */ |
198 | |
199 | mutex_enter(lcv->u_obj.vmobjlock); |
200 | lcv->u_obj.uo_refs++; |
201 | mutex_exit(lcv->u_obj.vmobjlock); |
202 | |
203 | mutex_enter(&udv_lock); |
204 | if (lcv->u_flags & UVM_DEVICE_WANTED) |
205 | wakeup(lcv); |
206 | lcv->u_flags &= ~(UVM_DEVICE_WANTED|UVM_DEVICE_HOLD); |
207 | mutex_exit(&udv_lock); |
208 | return(&lcv->u_obj); |
209 | } |
210 | |
211 | /* |
212 | * Did not find it on main list. Need to allocate a new one. |
213 | */ |
214 | |
215 | mutex_exit(&udv_lock); |
216 | |
217 | /* Note: both calls may allocate memory and sleep. */ |
218 | udv = kmem_alloc(sizeof(*udv), KM_SLEEP); |
219 | uvm_obj_init(&udv->u_obj, &uvm_deviceops, true, 1); |
220 | |
221 | mutex_enter(&udv_lock); |
222 | |
223 | /* |
224 | * now we have to double check to make sure no one added it |
225 | * to the list while we were sleeping... |
226 | */ |
227 | |
228 | LIST_FOREACH(lcv, &udv_list, u_list) { |
229 | if (device == lcv->u_device) |
230 | break; |
231 | } |
232 | |
233 | /* |
234 | * did we lose a race to someone else? |
235 | * free our memory and retry. |
236 | */ |
237 | |
238 | if (lcv) { |
239 | mutex_exit(&udv_lock); |
240 | uvm_obj_destroy(&udv->u_obj, true); |
241 | kmem_free(udv, sizeof(*udv)); |
242 | continue; |
243 | } |
244 | |
245 | /* |
246 | * we have it! init the data structures, add to list |
247 | * and return. |
248 | */ |
249 | |
250 | udv->u_flags = 0; |
251 | udv->u_device = device; |
252 | LIST_INSERT_HEAD(&udv_list, udv, u_list); |
253 | mutex_exit(&udv_lock); |
254 | return(&udv->u_obj); |
255 | } |
256 | /*NOTREACHED*/ |
257 | } |
258 | |
259 | /* |
260 | * udv_reference |
261 | * |
262 | * add a reference to a VM object. Note that the reference count must |
263 | * already be one (the passed in reference) so there is no chance of the |
264 | * udv being released or locked out here. |
265 | * |
266 | * => caller must call with object unlocked. |
267 | */ |
268 | |
269 | static void |
270 | udv_reference(struct uvm_object *uobj) |
271 | { |
272 | UVMHIST_FUNC("udv_reference" ); UVMHIST_CALLED(maphist); |
273 | |
274 | mutex_enter(uobj->vmobjlock); |
275 | uobj->uo_refs++; |
276 | UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)" , |
277 | uobj, uobj->uo_refs,0,0); |
278 | mutex_exit(uobj->vmobjlock); |
279 | } |
280 | |
281 | /* |
282 | * udv_detach |
283 | * |
284 | * remove a reference to a VM object. |
285 | * |
286 | * => caller must call with object unlocked and map locked. |
287 | */ |
288 | |
289 | static void |
290 | udv_detach(struct uvm_object *uobj) |
291 | { |
292 | struct uvm_device *udv = (struct uvm_device *)uobj; |
293 | UVMHIST_FUNC("udv_detach" ); UVMHIST_CALLED(maphist); |
294 | |
295 | /* |
296 | * loop until done |
297 | */ |
298 | again: |
299 | mutex_enter(uobj->vmobjlock); |
300 | if (uobj->uo_refs > 1) { |
301 | uobj->uo_refs--; |
302 | mutex_exit(uobj->vmobjlock); |
303 | UVMHIST_LOG(maphist," <- done, uobj=0x%x, ref=%d" , |
304 | uobj,uobj->uo_refs,0,0); |
305 | return; |
306 | } |
307 | |
308 | /* |
309 | * is it being held? if so, wait until others are done. |
310 | */ |
311 | |
312 | mutex_enter(&udv_lock); |
313 | if (udv->u_flags & UVM_DEVICE_HOLD) { |
314 | udv->u_flags |= UVM_DEVICE_WANTED; |
315 | mutex_exit(uobj->vmobjlock); |
316 | UVM_UNLOCK_AND_WAIT(udv, &udv_lock, false, "udv_detach" ,0); |
317 | goto again; |
318 | } |
319 | |
320 | /* |
321 | * got it! nuke it now. |
322 | */ |
323 | |
324 | LIST_REMOVE(udv, u_list); |
325 | if (udv->u_flags & UVM_DEVICE_WANTED) |
326 | wakeup(udv); |
327 | mutex_exit(&udv_lock); |
328 | mutex_exit(uobj->vmobjlock); |
329 | |
330 | uvm_obj_destroy(uobj, true); |
331 | kmem_free(udv, sizeof(*udv)); |
332 | UVMHIST_LOG(maphist," <- done, freed uobj=0x%x" , uobj,0,0,0); |
333 | } |
334 | |
335 | /* |
336 | * udv_fault: non-standard fault routine for device "pages" |
337 | * |
338 | * => rather than having a "get" function, we have a fault routine |
339 | * since we don't return vm_pages we need full control over the |
340 | * pmap_enter map in |
341 | * => all the usual fault data structured are locked by the caller |
342 | * (i.e. maps(read), amap (if any), uobj) |
343 | * => on return, we unlock all fault data structures |
344 | * => flags: PGO_ALLPAGES: get all of the pages |
345 | * PGO_LOCKED: fault data structures are locked |
346 | * XXX: currently PGO_LOCKED is always required ... consider removing |
347 | * it as a flag |
348 | * => NOTE: vaddr is the VA of pps[0] in ufi->entry, _NOT_ pps[centeridx] |
349 | */ |
350 | |
351 | static int |
352 | udv_fault(struct uvm_faultinfo *ufi, vaddr_t vaddr, struct vm_page **pps, |
353 | int npages, int centeridx, vm_prot_t access_type, |
354 | int flags) |
355 | { |
356 | struct vm_map_entry *entry = ufi->entry; |
357 | struct uvm_object *uobj = entry->object.uvm_obj; |
358 | struct uvm_device *udv = (struct uvm_device *)uobj; |
359 | vaddr_t curr_va; |
360 | off_t curr_offset; |
361 | paddr_t paddr, mdpgno; |
362 | u_int mmapflags; |
363 | int lcv, retval; |
364 | dev_t device; |
365 | vm_prot_t mapprot; |
366 | UVMHIST_FUNC("udv_fault" ); UVMHIST_CALLED(maphist); |
367 | UVMHIST_LOG(maphist," flags=%d" , flags,0,0,0); |
368 | |
369 | /* |
370 | * we do not allow device mappings to be mapped copy-on-write |
371 | * so we kill any attempt to do so here. |
372 | */ |
373 | |
374 | if (UVM_ET_ISCOPYONWRITE(entry)) { |
375 | UVMHIST_LOG(maphist, "<- failed -- COW entry (etype=0x%x)" , |
376 | entry->etype, 0,0,0); |
377 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
378 | return(EIO); |
379 | } |
380 | |
381 | /* |
382 | * get device map function. |
383 | */ |
384 | |
385 | device = udv->u_device; |
386 | if (cdevsw_lookup(device) == NULL) { |
387 | /* XXX This should not happen */ |
388 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
389 | return (EIO); |
390 | } |
391 | |
392 | /* |
393 | * now we must determine the offset in udv to use and the VA to |
394 | * use for pmap_enter. note that we always use orig_map's pmap |
395 | * for pmap_enter (even if we have a submap). since virtual |
396 | * addresses in a submap must match the main map, this is ok. |
397 | */ |
398 | |
399 | /* udv offset = (offset from start of entry) + entry's offset */ |
400 | curr_offset = entry->offset + (vaddr - entry->start); |
401 | /* pmap va = vaddr (virtual address of pps[0]) */ |
402 | curr_va = vaddr; |
403 | |
404 | /* |
405 | * loop over the page range entering in as needed |
406 | */ |
407 | |
408 | retval = 0; |
409 | for (lcv = 0 ; lcv < npages ; lcv++, curr_offset += PAGE_SIZE, |
410 | curr_va += PAGE_SIZE) { |
411 | if ((flags & PGO_ALLPAGES) == 0 && lcv != centeridx) |
412 | continue; |
413 | |
414 | if (pps[lcv] == PGO_DONTCARE) |
415 | continue; |
416 | |
417 | mdpgno = cdev_mmap(device, curr_offset, access_type); |
418 | if (mdpgno == -1) { |
419 | retval = EIO; |
420 | break; |
421 | } |
422 | paddr = pmap_phys_address(mdpgno); |
423 | mmapflags = pmap_mmap_flags(mdpgno); |
424 | mapprot = ufi->entry->protection; |
425 | UVMHIST_LOG(maphist, |
426 | " MAPPING: device: pm=0x%x, va=0x%x, pa=0x%lx, at=%d" , |
427 | ufi->orig_map->pmap, curr_va, paddr, mapprot); |
428 | if (pmap_enter(ufi->orig_map->pmap, curr_va, paddr, mapprot, |
429 | PMAP_CANFAIL | mapprot | mmapflags) != 0) { |
430 | /* |
431 | * pmap_enter() didn't have the resource to |
432 | * enter this mapping. Unlock everything, |
433 | * wait for the pagedaemon to free up some |
434 | * pages, and then tell uvm_fault() to start |
435 | * the fault again. |
436 | * |
437 | * XXX Needs some rethinking for the PGO_ALLPAGES |
438 | * XXX case. |
439 | */ |
440 | pmap_update(ufi->orig_map->pmap); /* sync what we have so far */ |
441 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, |
442 | uobj); |
443 | uvm_wait("udv_fault" ); |
444 | return (ERESTART); |
445 | } |
446 | } |
447 | |
448 | pmap_update(ufi->orig_map->pmap); |
449 | uvmfault_unlockall(ufi, ufi->entry->aref.ar_amap, uobj); |
450 | return (retval); |
451 | } |
452 | |