xref: /titanic_50/usr/src/uts/common/vm/seg_dev.c (revision b56bf881a9655cb27b53cba1468312f7c6dfb0a2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 /*
41  * VM - segment of a mapped device.
42  *
43  * This segment driver is used when mapping character special devices.
44  */
45 
46 #include <sys/types.h>
47 #include <sys/t_lock.h>
48 #include <sys/sysmacros.h>
49 #include <sys/vtrace.h>
50 #include <sys/systm.h>
51 #include <sys/vmsystm.h>
52 #include <sys/mman.h>
53 #include <sys/errno.h>
54 #include <sys/kmem.h>
55 #include <sys/cmn_err.h>
56 #include <sys/vnode.h>
57 #include <sys/proc.h>
58 #include <sys/conf.h>
59 #include <sys/debug.h>
60 #include <sys/ddidevmap.h>
61 #include <sys/ddi_implfuncs.h>
62 #include <sys/lgrp.h>
63 
64 #include <vm/page.h>
65 #include <vm/hat.h>
66 #include <vm/as.h>
67 #include <vm/seg.h>
68 #include <vm/seg_dev.h>
69 #include <vm/seg_kp.h>
70 #include <vm/seg_kmem.h>
71 #include <vm/vpage.h>
72 
73 #include <sys/sunddi.h>
74 #include <sys/esunddi.h>
75 #include <sys/fs/snode.h>
76 
77 
78 #if DEBUG
79 int segdev_debug;
80 #define	DEBUGF(level, args) { if (segdev_debug >= (level)) cmn_err args; }
81 #else
82 #define	DEBUGF(level, args)
83 #endif
84 
85 /* Default timeout for devmap context management */
86 #define	CTX_TIMEOUT_VALUE 0
87 
88 #define	HOLD_DHP_LOCK(dhp)  if (dhp->dh_flags & DEVMAP_ALLOW_REMAP) \
89 			{ mutex_enter(&dhp->dh_lock); }
90 
91 #define	RELE_DHP_LOCK(dhp) if (dhp->dh_flags & DEVMAP_ALLOW_REMAP) \
92 			{ mutex_exit(&dhp->dh_lock); }
93 
94 #define	round_down_p2(a, s)	((a) & ~((s) - 1))
95 #define	round_up_p2(a, s)	(((a) + (s) - 1) & ~((s) - 1))
96 
97 /*
98  * VA_PA_ALIGNED checks to see if both VA and PA are on pgsize boundary
99  * VA_PA_PGSIZE_ALIGNED check to see if VA is aligned with PA w.r.t. pgsize
100  */
101 #define	VA_PA_ALIGNED(uvaddr, paddr, pgsize)		\
102 	(((uvaddr | paddr) & (pgsize - 1)) == 0)
103 #define	VA_PA_PGSIZE_ALIGNED(uvaddr, paddr, pgsize)	\
104 	(((uvaddr ^ paddr) & (pgsize - 1)) == 0)
105 
106 #define	vpgtob(n)	((n) * sizeof (struct vpage))	/* For brevity */
107 
108 #define	VTOCVP(vp)	(VTOS(vp)->s_commonvp)	/* we "know" it's an snode */
109 
110 static struct devmap_ctx *devmapctx_list = NULL;
111 static struct devmap_softlock *devmap_slist = NULL;
112 
113 /*
114  * mutex, vnode and page for the page of zeros we use for the trash mappings.
115  * One trash page is allocated on the first ddi_umem_setup call that uses it
116  * XXX Eventually, we may want to combine this with what segnf does when all
117  * hat layers implement HAT_NOFAULT.
118  *
119  * The trash page is used when the backing store for a userland mapping is
120  * removed but the application semantics do not take kindly to a SIGBUS.
121  * In that scenario, the applications pages are mapped to some dummy page
122  * which returns garbage on read and writes go into a common place.
123  * (Perfect for NO_FAULT semantics)
124  * The device driver is responsible to communicating to the app with some
125  * other mechanism that such remapping has happened and the app should take
126  * corrective action.
127  * We can also use an anonymous memory page as there is no requirement to
128  * keep the page locked, however this complicates the fault code. RFE.
129  */
130 static struct vnode trashvp;
131 static struct page *trashpp;
132 
133 /* Non-pageable kernel memory is allocated from the umem_np_arena. */
134 static vmem_t *umem_np_arena;
135 
136 /* Set the cookie to a value we know will never be a valid umem_cookie */
137 #define	DEVMAP_DEVMEM_COOKIE	((ddi_umem_cookie_t)0x1)
138 
139 /*
140  * Macros to check if type of devmap handle
141  */
142 #define	cookie_is_devmem(c)	\
143 	((c) == (struct ddi_umem_cookie *)DEVMAP_DEVMEM_COOKIE)
144 
145 #define	cookie_is_pmem(c)	\
146 	((c) == (struct ddi_umem_cookie *)DEVMAP_PMEM_COOKIE)
147 
148 #define	cookie_is_kpmem(c)	(!cookie_is_devmem(c) && !cookie_is_pmem(c) &&\
149 	((c)->type == KMEM_PAGEABLE))
150 
151 #define	dhp_is_devmem(dhp)	\
152 	(cookie_is_devmem((struct ddi_umem_cookie *)((dhp)->dh_cookie)))
153 
154 #define	dhp_is_pmem(dhp)	\
155 	(cookie_is_pmem((struct ddi_umem_cookie *)((dhp)->dh_cookie)))
156 
157 #define	dhp_is_kpmem(dhp)	\
158 	(cookie_is_kpmem((struct ddi_umem_cookie *)((dhp)->dh_cookie)))
159 
160 /*
161  * Private seg op routines.
162  */
163 static int	segdev_dup(struct seg *, struct seg *);
164 static int	segdev_unmap(struct seg *, caddr_t, size_t);
165 static void	segdev_free(struct seg *);
166 static faultcode_t segdev_fault(struct hat *, struct seg *, caddr_t, size_t,
167 		    enum fault_type, enum seg_rw);
168 static faultcode_t segdev_faulta(struct seg *, caddr_t);
169 static int	segdev_setprot(struct seg *, caddr_t, size_t, uint_t);
170 static int	segdev_checkprot(struct seg *, caddr_t, size_t, uint_t);
171 static void	segdev_badop(void);
172 static int	segdev_sync(struct seg *, caddr_t, size_t, int, uint_t);
173 static size_t	segdev_incore(struct seg *, caddr_t, size_t, char *);
174 static int	segdev_lockop(struct seg *, caddr_t, size_t, int, int,
175 		    ulong_t *, size_t);
176 static int	segdev_getprot(struct seg *, caddr_t, size_t, uint_t *);
177 static u_offset_t	segdev_getoffset(struct seg *, caddr_t);
178 static int	segdev_gettype(struct seg *, caddr_t);
179 static int	segdev_getvp(struct seg *, caddr_t, struct vnode **);
180 static int	segdev_advise(struct seg *, caddr_t, size_t, uint_t);
181 static void	segdev_dump(struct seg *);
182 static int	segdev_pagelock(struct seg *, caddr_t, size_t,
183 		    struct page ***, enum lock_type, enum seg_rw);
184 static int	segdev_setpagesize(struct seg *, caddr_t, size_t, uint_t);
185 static int	segdev_getmemid(struct seg *, caddr_t, memid_t *);
186 static lgrp_mem_policy_info_t	*segdev_getpolicy(struct seg *, caddr_t);
187 static int	segdev_capable(struct seg *, segcapability_t);
188 
189 /*
190  * XXX	this struct is used by rootnex_map_fault to identify
191  *	the segment it has been passed. So if you make it
192  *	"static" you'll need to fix rootnex_map_fault.
193  */
194 struct seg_ops segdev_ops = {
195 	segdev_dup,
196 	segdev_unmap,
197 	segdev_free,
198 	segdev_fault,
199 	segdev_faulta,
200 	segdev_setprot,
201 	segdev_checkprot,
202 	(int (*)())segdev_badop,	/* kluster */
203 	(size_t (*)(struct seg *))NULL,	/* swapout */
204 	segdev_sync,			/* sync */
205 	segdev_incore,
206 	segdev_lockop,			/* lockop */
207 	segdev_getprot,
208 	segdev_getoffset,
209 	segdev_gettype,
210 	segdev_getvp,
211 	segdev_advise,
212 	segdev_dump,
213 	segdev_pagelock,
214 	segdev_setpagesize,
215 	segdev_getmemid,
216 	segdev_getpolicy,
217 	segdev_capable,
218 };
219 
220 /*
221  * Private segdev support routines
222  */
223 static struct segdev_data *sdp_alloc(void);
224 
225 static void segdev_softunlock(struct hat *, struct seg *, caddr_t,
226     size_t, enum seg_rw);
227 
228 static faultcode_t segdev_faultpage(struct hat *, struct seg *, caddr_t,
229     struct vpage *, enum fault_type, enum seg_rw, devmap_handle_t *);
230 
231 static faultcode_t segdev_faultpages(struct hat *, struct seg *, caddr_t,
232     size_t, enum fault_type, enum seg_rw, devmap_handle_t *);
233 
234 static struct devmap_ctx *devmap_ctxinit(dev_t, ulong_t);
235 static struct devmap_softlock *devmap_softlock_init(dev_t, ulong_t);
236 static void devmap_softlock_rele(devmap_handle_t *);
237 static void devmap_ctx_rele(devmap_handle_t *);
238 
239 static void devmap_ctxto(void *);
240 
241 static devmap_handle_t *devmap_find_handle(devmap_handle_t *dhp_head,
242     caddr_t addr);
243 
244 static ulong_t devmap_roundup(devmap_handle_t *dhp, ulong_t offset, size_t len,
245     ulong_t *opfn, ulong_t *pagesize);
246 
247 static void free_devmap_handle(devmap_handle_t *dhp);
248 
249 static int devmap_handle_dup(devmap_handle_t *dhp, devmap_handle_t **new_dhp,
250     struct seg *newseg);
251 
252 static devmap_handle_t *devmap_handle_unmap(devmap_handle_t *dhp);
253 
254 static void devmap_handle_unmap_head(devmap_handle_t *dhp, size_t len);
255 
256 static void devmap_handle_unmap_tail(devmap_handle_t *dhp, caddr_t addr);
257 
258 static int devmap_device(devmap_handle_t *dhp, struct as *as, caddr_t *addr,
259     offset_t off, size_t len, uint_t flags);
260 
261 static void devmap_get_large_pgsize(devmap_handle_t *dhp, size_t len,
262     caddr_t addr, size_t *llen, caddr_t *laddr);
263 
264 static void devmap_handle_reduce_len(devmap_handle_t *dhp, size_t len);
265 
266 static void *devmap_alloc_pages(vmem_t *vmp, size_t size, int vmflag);
267 static void devmap_free_pages(vmem_t *vmp, void *inaddr, size_t size);
268 
269 static void *devmap_umem_alloc_np(size_t size, size_t flags);
270 static void devmap_umem_free_np(void *addr, size_t size);
271 
272 /*
273  * routines to lock and unlock underlying segkp segment for
274  * KMEM_PAGEABLE type cookies.
275  */
276 static faultcode_t  acquire_kpmem_lock(struct ddi_umem_cookie *, size_t);
277 static void release_kpmem_lock(struct ddi_umem_cookie *, size_t);
278 
279 /*
280  * Routines to synchronize F_SOFTLOCK and F_INVAL faults for
281  * drivers with devmap_access callbacks
282  */
283 static int devmap_softlock_enter(struct devmap_softlock *, size_t,
284 	enum fault_type);
285 static void devmap_softlock_exit(struct devmap_softlock *, size_t,
286 	enum fault_type);
287 
288 static kmutex_t devmapctx_lock;
289 
290 static kmutex_t devmap_slock;
291 
292 /*
293  * Initialize the thread callbacks and thread private data.
294  */
295 static struct devmap_ctx *
296 devmap_ctxinit(dev_t dev, ulong_t id)
297 {
298 	struct devmap_ctx	*devctx;
299 	struct devmap_ctx	*tmp;
300 	dev_info_t		*dip;
301 
302 	tmp =  kmem_zalloc(sizeof (struct devmap_ctx), KM_SLEEP);
303 
304 	mutex_enter(&devmapctx_lock);
305 
306 	dip = e_ddi_hold_devi_by_dev(dev, 0);
307 	ASSERT(dip != NULL);
308 	ddi_release_devi(dip);
309 
310 	for (devctx = devmapctx_list; devctx != NULL; devctx = devctx->next)
311 		if ((devctx->dip == dip) && (devctx->id == id))
312 			break;
313 
314 	if (devctx == NULL) {
315 		devctx = tmp;
316 		devctx->dip = dip;
317 		devctx->id = id;
318 		mutex_init(&devctx->lock, NULL, MUTEX_DEFAULT, NULL);
319 		cv_init(&devctx->cv, NULL, CV_DEFAULT, NULL);
320 		devctx->next = devmapctx_list;
321 		devmapctx_list = devctx;
322 	} else
323 		kmem_free(tmp, sizeof (struct devmap_ctx));
324 
325 	mutex_enter(&devctx->lock);
326 	devctx->refcnt++;
327 	mutex_exit(&devctx->lock);
328 	mutex_exit(&devmapctx_lock);
329 
330 	return (devctx);
331 }
332 
333 /*
334  * Timeout callback called if a CPU has not given up the device context
335  * within dhp->dh_timeout_length ticks
336  */
337 static void
338 devmap_ctxto(void *data)
339 {
340 	struct devmap_ctx *devctx = data;
341 
342 	TRACE_1(TR_FAC_DEVMAP, TR_DEVMAP_CTXTO,
343 	    "devmap_ctxto:timeout expired, devctx=%p", (void *)devctx);
344 	mutex_enter(&devctx->lock);
345 	/*
346 	 * Set oncpu = 0 so the next mapping trying to get the device context
347 	 * can.
348 	 */
349 	devctx->oncpu = 0;
350 	devctx->timeout = 0;
351 	cv_signal(&devctx->cv);
352 	mutex_exit(&devctx->lock);
353 }
354 
355 /*
356  * Create a device segment.
357  */
358 int
359 segdev_create(struct seg *seg, void *argsp)
360 {
361 	struct segdev_data *sdp;
362 	struct segdev_crargs *a = (struct segdev_crargs *)argsp;
363 	devmap_handle_t *dhp = (devmap_handle_t *)a->devmap_data;
364 	int error;
365 
366 	/*
367 	 * Since the address space is "write" locked, we
368 	 * don't need the segment lock to protect "segdev" data.
369 	 */
370 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
371 
372 	hat_map(seg->s_as->a_hat, seg->s_base, seg->s_size, HAT_MAP);
373 
374 	sdp = sdp_alloc();
375 
376 	sdp->mapfunc = a->mapfunc;
377 	sdp->offset = a->offset;
378 	sdp->prot = a->prot;
379 	sdp->maxprot = a->maxprot;
380 	sdp->type = a->type;
381 	sdp->pageprot = 0;
382 	sdp->softlockcnt = 0;
383 	sdp->vpage = NULL;
384 
385 	if (sdp->mapfunc == NULL)
386 		sdp->devmap_data = dhp;
387 	else
388 		sdp->devmap_data = dhp = NULL;
389 
390 	sdp->hat_flags = a->hat_flags;
391 	sdp->hat_attr = a->hat_attr;
392 
393 	/*
394 	 * Currently, hat_flags supports only HAT_LOAD_NOCONSIST
395 	 */
396 	ASSERT(!(sdp->hat_flags & ~HAT_LOAD_NOCONSIST));
397 
398 	/*
399 	 * Hold shadow vnode -- segdev only deals with
400 	 * character (VCHR) devices. We use the common
401 	 * vp to hang pages on.
402 	 */
403 	sdp->vp = specfind(a->dev, VCHR);
404 	ASSERT(sdp->vp != NULL);
405 
406 	seg->s_ops = &segdev_ops;
407 	seg->s_data = sdp;
408 
409 	while (dhp != NULL) {
410 		dhp->dh_seg = seg;
411 		dhp = dhp->dh_next;
412 	}
413 
414 	/*
415 	 * Inform the vnode of the new mapping.
416 	 */
417 	/*
418 	 * It is ok to use pass sdp->maxprot to ADDMAP rather than to use
419 	 * dhp specific maxprot because spec_addmap does not use maxprot.
420 	 */
421 	error = VOP_ADDMAP(VTOCVP(sdp->vp), sdp->offset,
422 	    seg->s_as, seg->s_base, seg->s_size,
423 	    sdp->prot, sdp->maxprot, sdp->type, CRED(), NULL);
424 
425 	if (error != 0) {
426 		sdp->devmap_data = NULL;
427 		hat_unload(seg->s_as->a_hat, seg->s_base, seg->s_size,
428 		    HAT_UNLOAD_UNMAP);
429 	} else {
430 		/*
431 		 * Mappings of /dev/null don't count towards the VSZ of a
432 		 * process.  Mappings of /dev/null have no mapping type.
433 		 */
434 		if ((SEGOP_GETTYPE(seg, (seg)->s_base) & (MAP_SHARED |
435 		    MAP_PRIVATE)) == 0) {
436 			seg->s_as->a_resvsize -= seg->s_size;
437 		}
438 	}
439 
440 	return (error);
441 }
442 
443 static struct segdev_data *
444 sdp_alloc(void)
445 {
446 	struct segdev_data *sdp;
447 
448 	sdp = kmem_zalloc(sizeof (struct segdev_data), KM_SLEEP);
449 	rw_init(&sdp->lock, NULL, RW_DEFAULT, NULL);
450 
451 	return (sdp);
452 }
453 
454 /*
455  * Duplicate seg and return new segment in newseg.
456  */
457 static int
458 segdev_dup(struct seg *seg, struct seg *newseg)
459 {
460 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
461 	struct segdev_data *newsdp;
462 	devmap_handle_t *dhp = (devmap_handle_t *)sdp->devmap_data;
463 	size_t npages;
464 	int ret;
465 
466 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_DUP,
467 	    "segdev_dup:start dhp=%p, seg=%p", (void *)dhp, (void *)seg);
468 
469 	DEBUGF(3, (CE_CONT, "segdev_dup: dhp %p seg %p\n",
470 	    (void *)dhp, (void *)seg));
471 
472 	/*
473 	 * Since the address space is "write" locked, we
474 	 * don't need the segment lock to protect "segdev" data.
475 	 */
476 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
477 
478 	newsdp = sdp_alloc();
479 
480 	newseg->s_ops = seg->s_ops;
481 	newseg->s_data = (void *)newsdp;
482 
483 	VN_HOLD(sdp->vp);
484 	newsdp->vp 	= sdp->vp;
485 	newsdp->mapfunc = sdp->mapfunc;
486 	newsdp->offset	= sdp->offset;
487 	newsdp->pageprot = sdp->pageprot;
488 	newsdp->prot	= sdp->prot;
489 	newsdp->maxprot = sdp->maxprot;
490 	newsdp->type = sdp->type;
491 	newsdp->hat_attr = sdp->hat_attr;
492 	newsdp->hat_flags = sdp->hat_flags;
493 	newsdp->softlockcnt = 0;
494 
495 	/*
496 	 * Initialize per page data if the segment we are
497 	 * dup'ing has per page information.
498 	 */
499 	npages = seg_pages(newseg);
500 
501 	if (sdp->vpage != NULL) {
502 		size_t nbytes = vpgtob(npages);
503 
504 		newsdp->vpage = kmem_zalloc(nbytes, KM_SLEEP);
505 		bcopy(sdp->vpage, newsdp->vpage, nbytes);
506 	} else
507 		newsdp->vpage = NULL;
508 
509 	/*
510 	 * duplicate devmap handles
511 	 */
512 	if (dhp != NULL) {
513 		ret = devmap_handle_dup(dhp,
514 		    (devmap_handle_t **)&newsdp->devmap_data, newseg);
515 		if (ret != 0) {
516 			TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_DUP_CK1,
517 			    "segdev_dup:ret1 ret=%x, dhp=%p seg=%p",
518 			    ret, (void *)dhp, (void *)seg);
519 			DEBUGF(1, (CE_CONT,
520 			    "segdev_dup: ret %x dhp %p seg %p\n",
521 			    ret, (void *)dhp, (void *)seg));
522 			return (ret);
523 		}
524 	}
525 
526 	/*
527 	 * Inform the common vnode of the new mapping.
528 	 */
529 	return (VOP_ADDMAP(VTOCVP(newsdp->vp),
530 	    newsdp->offset, newseg->s_as,
531 	    newseg->s_base, newseg->s_size, newsdp->prot,
532 	    newsdp->maxprot, sdp->type, CRED(), NULL));
533 }
534 
535 /*
536  * duplicate devmap handles
537  */
538 static int
539 devmap_handle_dup(devmap_handle_t *dhp, devmap_handle_t **new_dhp,
540     struct seg *newseg)
541 {
542 	devmap_handle_t *newdhp_save = NULL;
543 	devmap_handle_t *newdhp = NULL;
544 	struct devmap_callback_ctl *callbackops;
545 
546 	while (dhp != NULL) {
547 		newdhp = kmem_alloc(sizeof (devmap_handle_t), KM_SLEEP);
548 
549 		/* Need to lock the original dhp while copying if REMAP */
550 		HOLD_DHP_LOCK(dhp);
551 		bcopy(dhp, newdhp, sizeof (devmap_handle_t));
552 		RELE_DHP_LOCK(dhp);
553 		newdhp->dh_seg = newseg;
554 		newdhp->dh_next = NULL;
555 		if (newdhp_save != NULL)
556 			newdhp_save->dh_next = newdhp;
557 		else
558 			*new_dhp = newdhp;
559 		newdhp_save = newdhp;
560 
561 		callbackops = &newdhp->dh_callbackops;
562 
563 		if (dhp->dh_softlock != NULL)
564 			newdhp->dh_softlock = devmap_softlock_init(
565 			    newdhp->dh_dev,
566 			    (ulong_t)callbackops->devmap_access);
567 		if (dhp->dh_ctx != NULL)
568 			newdhp->dh_ctx = devmap_ctxinit(newdhp->dh_dev,
569 			    (ulong_t)callbackops->devmap_access);
570 
571 		/*
572 		 * Initialize dh_lock if we want to do remap.
573 		 */
574 		if (newdhp->dh_flags & DEVMAP_ALLOW_REMAP) {
575 			mutex_init(&newdhp->dh_lock, NULL, MUTEX_DEFAULT, NULL);
576 			newdhp->dh_flags |= DEVMAP_LOCK_INITED;
577 		}
578 
579 		if (callbackops->devmap_dup != NULL) {
580 			int ret;
581 
582 			/*
583 			 * Call the dup callback so that the driver can
584 			 * duplicate its private data.
585 			 */
586 			ret = (*callbackops->devmap_dup)(dhp, dhp->dh_pvtp,
587 			    (devmap_cookie_t *)newdhp, &newdhp->dh_pvtp);
588 
589 			if (ret != 0) {
590 				/*
591 				 * We want to free up this segment as the driver
592 				 * has indicated that we can't dup it.  But we
593 				 * don't want to call the drivers, devmap_unmap,
594 				 * callback function as the driver does not
595 				 * think this segment exists. The caller of
596 				 * devmap_dup will call seg_free on newseg
597 				 * as it was the caller that allocated the
598 				 * segment.
599 				 */
600 				DEBUGF(1, (CE_CONT, "devmap_handle_dup ERROR: "
601 				    "newdhp %p dhp %p\n", (void *)newdhp,
602 				    (void *)dhp));
603 				callbackops->devmap_unmap = NULL;
604 				return (ret);
605 			}
606 		}
607 
608 		dhp = dhp->dh_next;
609 	}
610 
611 	return (0);
612 }
613 
614 /*
615  * Split a segment at addr for length len.
616  */
617 /*ARGSUSED*/
618 static int
619 segdev_unmap(struct seg *seg, caddr_t addr, size_t len)
620 {
621 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
622 	register struct segdev_data *nsdp;
623 	register struct seg *nseg;
624 	register size_t	opages;		/* old segment size in pages */
625 	register size_t	npages;		/* new segment size in pages */
626 	register size_t	dpages;		/* pages being deleted (unmapped) */
627 	register size_t	nbytes;
628 	devmap_handle_t *dhp = (devmap_handle_t *)sdp->devmap_data;
629 	devmap_handle_t *dhpp;
630 	devmap_handle_t *newdhp;
631 	struct devmap_callback_ctl *callbackops;
632 	caddr_t nbase;
633 	offset_t off;
634 	ulong_t nsize;
635 	size_t mlen, sz;
636 
637 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_UNMAP,
638 	    "segdev_unmap:start dhp=%p, seg=%p addr=%p len=%lx",
639 	    (void *)dhp, (void *)seg, (void *)addr, len);
640 
641 	DEBUGF(3, (CE_CONT, "segdev_unmap: dhp %p seg %p addr %p len %lx\n",
642 	    (void *)dhp, (void *)seg, (void *)addr, len));
643 
644 	/*
645 	 * Since the address space is "write" locked, we
646 	 * don't need the segment lock to protect "segdev" data.
647 	 */
648 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
649 
650 	if ((sz = sdp->softlockcnt) > 0) {
651 		/*
652 		 * Fail the unmap if pages are SOFTLOCKed through this mapping.
653 		 * softlockcnt is protected from change by the as write lock.
654 		 */
655 		TRACE_1(TR_FAC_DEVMAP, TR_DEVMAP_UNMAP_CK1,
656 		    "segdev_unmap:error softlockcnt = %ld", sz);
657 		DEBUGF(1, (CE_CONT, "segdev_unmap: softlockcnt %ld\n", sz));
658 		return (EAGAIN);
659 	}
660 
661 	/*
662 	 * Check for bad sizes
663 	 */
664 	if (addr < seg->s_base || addr + len > seg->s_base + seg->s_size ||
665 	    (len & PAGEOFFSET) || ((uintptr_t)addr & PAGEOFFSET))
666 		panic("segdev_unmap");
667 
668 	if (dhp != NULL) {
669 		devmap_handle_t *tdhp;
670 		/*
671 		 * If large page size was used in hat_devload(),
672 		 * the same page size must be used in hat_unload().
673 		 */
674 		dhpp = tdhp = devmap_find_handle(dhp, addr);
675 		while (tdhp != NULL) {
676 			if (tdhp->dh_flags & DEVMAP_FLAG_LARGE) {
677 				break;
678 			}
679 			tdhp = tdhp->dh_next;
680 		}
681 		if (tdhp != NULL) {	/* found a dhp using large pages */
682 			size_t slen = len;
683 			size_t mlen;
684 			size_t soff;
685 
686 			soff = (ulong_t)(addr - dhpp->dh_uvaddr);
687 			while (slen != 0) {
688 				mlen = MIN(slen, (dhpp->dh_len - soff));
689 				hat_unload(seg->s_as->a_hat, dhpp->dh_uvaddr,
690 				    dhpp->dh_len, HAT_UNLOAD_UNMAP);
691 				dhpp = dhpp->dh_next;
692 				ASSERT(slen >= mlen);
693 				slen -= mlen;
694 				soff = 0;
695 			}
696 		} else
697 			hat_unload(seg->s_as->a_hat, addr, len,
698 			    HAT_UNLOAD_UNMAP);
699 	} else {
700 		/*
701 		 * Unload any hardware translations in the range
702 		 * to be taken out.
703 		 */
704 		hat_unload(seg->s_as->a_hat, addr, len, HAT_UNLOAD_UNMAP);
705 	}
706 
707 	/*
708 	 * get the user offset which will used in the driver callbacks
709 	 */
710 	off = sdp->offset + (offset_t)(addr - seg->s_base);
711 
712 	/*
713 	 * Inform the vnode of the unmapping.
714 	 */
715 	ASSERT(sdp->vp != NULL);
716 	(void) VOP_DELMAP(VTOCVP(sdp->vp), off, seg->s_as, addr, len,
717 	    sdp->prot, sdp->maxprot, sdp->type, CRED(), NULL);
718 
719 	/*
720 	 * Check for entire segment
721 	 */
722 	if (addr == seg->s_base && len == seg->s_size) {
723 		seg_free(seg);
724 		return (0);
725 	}
726 
727 	opages = seg_pages(seg);
728 	dpages = btop(len);
729 	npages = opages - dpages;
730 
731 	/*
732 	 * Check for beginning of segment
733 	 */
734 	if (addr == seg->s_base) {
735 		if (sdp->vpage != NULL) {
736 			register struct vpage *ovpage;
737 
738 			ovpage = sdp->vpage;	/* keep pointer to vpage */
739 
740 			nbytes = vpgtob(npages);
741 			sdp->vpage = kmem_alloc(nbytes, KM_SLEEP);
742 			bcopy(&ovpage[dpages], sdp->vpage, nbytes);
743 
744 			/* free up old vpage */
745 			kmem_free(ovpage, vpgtob(opages));
746 		}
747 
748 		/*
749 		 * free devmap handles from the beginning of the mapping.
750 		 */
751 		if (dhp != NULL)
752 			devmap_handle_unmap_head(dhp, len);
753 
754 		sdp->offset += (offset_t)len;
755 
756 		seg->s_base += len;
757 		seg->s_size -= len;
758 
759 		return (0);
760 	}
761 
762 	/*
763 	 * Check for end of segment
764 	 */
765 	if (addr + len == seg->s_base + seg->s_size) {
766 		if (sdp->vpage != NULL) {
767 			register struct vpage *ovpage;
768 
769 			ovpage = sdp->vpage;	/* keep pointer to vpage */
770 
771 			nbytes = vpgtob(npages);
772 			sdp->vpage = kmem_alloc(nbytes, KM_SLEEP);
773 			bcopy(ovpage, sdp->vpage, nbytes);
774 
775 			/* free up old vpage */
776 			kmem_free(ovpage, vpgtob(opages));
777 		}
778 		seg->s_size -= len;
779 
780 		/*
781 		 * free devmap handles from addr to the end of the mapping.
782 		 */
783 		if (dhp != NULL)
784 			devmap_handle_unmap_tail(dhp, addr);
785 
786 		return (0);
787 	}
788 
789 	/*
790 	 * The section to go is in the middle of the segment,
791 	 * have to make it into two segments.  nseg is made for
792 	 * the high end while seg is cut down at the low end.
793 	 */
794 	nbase = addr + len;				/* new seg base */
795 	nsize = (seg->s_base + seg->s_size) - nbase;	/* new seg size */
796 	seg->s_size = addr - seg->s_base;		/* shrink old seg */
797 	nseg = seg_alloc(seg->s_as, nbase, nsize);
798 	if (nseg == NULL)
799 		panic("segdev_unmap seg_alloc");
800 
801 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_UNMAP_CK2,
802 	    "segdev_unmap: seg=%p nseg=%p", (void *)seg, (void *)nseg);
803 	DEBUGF(3, (CE_CONT, "segdev_unmap: segdev_dup seg %p nseg %p\n",
804 	    (void *)seg, (void *)nseg));
805 	nsdp = sdp_alloc();
806 
807 	nseg->s_ops = seg->s_ops;
808 	nseg->s_data = (void *)nsdp;
809 
810 	VN_HOLD(sdp->vp);
811 	nsdp->mapfunc = sdp->mapfunc;
812 	nsdp->offset = sdp->offset + (offset_t)(nseg->s_base - seg->s_base);
813 	nsdp->vp 	= sdp->vp;
814 	nsdp->pageprot = sdp->pageprot;
815 	nsdp->prot	= sdp->prot;
816 	nsdp->maxprot = sdp->maxprot;
817 	nsdp->type = sdp->type;
818 	nsdp->hat_attr = sdp->hat_attr;
819 	nsdp->hat_flags = sdp->hat_flags;
820 	nsdp->softlockcnt = 0;
821 
822 	/*
823 	 * Initialize per page data if the segment we are
824 	 * dup'ing has per page information.
825 	 */
826 	if (sdp->vpage != NULL) {
827 		/* need to split vpage into two arrays */
828 		register size_t nnbytes;
829 		register size_t nnpages;
830 		register struct vpage *ovpage;
831 
832 		ovpage = sdp->vpage;		/* keep pointer to vpage */
833 
834 		npages = seg_pages(seg);	/* seg has shrunk */
835 		nbytes = vpgtob(npages);
836 		nnpages = seg_pages(nseg);
837 		nnbytes = vpgtob(nnpages);
838 
839 		sdp->vpage = kmem_alloc(nbytes, KM_SLEEP);
840 		bcopy(ovpage, sdp->vpage, nbytes);
841 
842 		nsdp->vpage = kmem_alloc(nnbytes, KM_SLEEP);
843 		bcopy(&ovpage[npages + dpages], nsdp->vpage, nnbytes);
844 
845 		/* free up old vpage */
846 		kmem_free(ovpage, vpgtob(opages));
847 	} else
848 		nsdp->vpage = NULL;
849 
850 	/*
851 	 * unmap dhps.
852 	 */
853 	if (dhp == NULL) {
854 		nsdp->devmap_data = NULL;
855 		return (0);
856 	}
857 	while (dhp != NULL) {
858 		callbackops = &dhp->dh_callbackops;
859 		TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_UNMAP_CK3,
860 		    "segdev_unmap: dhp=%p addr=%p", dhp, addr);
861 		DEBUGF(3, (CE_CONT, "unmap: dhp %p addr %p uvaddr %p len %lx\n",
862 		    (void *)dhp, (void *)addr,
863 		    (void *)dhp->dh_uvaddr, dhp->dh_len));
864 
865 		if (addr == (dhp->dh_uvaddr + dhp->dh_len)) {
866 			dhpp = dhp->dh_next;
867 			dhp->dh_next = NULL;
868 			dhp = dhpp;
869 		} else if (addr > (dhp->dh_uvaddr + dhp->dh_len)) {
870 			dhp = dhp->dh_next;
871 		} else if (addr > dhp->dh_uvaddr &&
872 		    (addr + len) < (dhp->dh_uvaddr + dhp->dh_len)) {
873 			/*
874 			 * <addr, addr+len> is enclosed by dhp.
875 			 * create a newdhp that begins at addr+len and
876 			 * ends at dhp->dh_uvaddr+dhp->dh_len.
877 			 */
878 			newdhp = kmem_alloc(sizeof (devmap_handle_t), KM_SLEEP);
879 			HOLD_DHP_LOCK(dhp);
880 			bcopy(dhp, newdhp, sizeof (devmap_handle_t));
881 			RELE_DHP_LOCK(dhp);
882 			newdhp->dh_seg = nseg;
883 			newdhp->dh_next = dhp->dh_next;
884 			if (dhp->dh_softlock != NULL)
885 				newdhp->dh_softlock = devmap_softlock_init(
886 				    newdhp->dh_dev,
887 				    (ulong_t)callbackops->devmap_access);
888 			if (dhp->dh_ctx != NULL)
889 				newdhp->dh_ctx = devmap_ctxinit(newdhp->dh_dev,
890 				    (ulong_t)callbackops->devmap_access);
891 			if (newdhp->dh_flags & DEVMAP_LOCK_INITED) {
892 				mutex_init(&newdhp->dh_lock,
893 				    NULL, MUTEX_DEFAULT, NULL);
894 			}
895 			if (callbackops->devmap_unmap != NULL)
896 				(*callbackops->devmap_unmap)(dhp, dhp->dh_pvtp,
897 				    off, len, dhp, &dhp->dh_pvtp,
898 				    newdhp, &newdhp->dh_pvtp);
899 			mlen = len + (addr - dhp->dh_uvaddr);
900 			devmap_handle_reduce_len(newdhp, mlen);
901 			nsdp->devmap_data = newdhp;
902 			/* XX Changing len should recalculate LARGE flag */
903 			dhp->dh_len = addr - dhp->dh_uvaddr;
904 			dhpp = dhp->dh_next;
905 			dhp->dh_next = NULL;
906 			dhp = dhpp;
907 		} else if ((addr > dhp->dh_uvaddr) &&
908 		    ((addr + len) >= (dhp->dh_uvaddr + dhp->dh_len))) {
909 			mlen = dhp->dh_len + dhp->dh_uvaddr - addr;
910 			/*
911 			 * <addr, addr+len> spans over dhps.
912 			 */
913 			if (callbackops->devmap_unmap != NULL)
914 				(*callbackops->devmap_unmap)(dhp, dhp->dh_pvtp,
915 				    off, mlen, (devmap_cookie_t *)dhp,
916 				    &dhp->dh_pvtp, NULL, NULL);
917 			/* XX Changing len should recalculate LARGE flag */
918 			dhp->dh_len = addr - dhp->dh_uvaddr;
919 			dhpp = dhp->dh_next;
920 			dhp->dh_next = NULL;
921 			dhp = dhpp;
922 			nsdp->devmap_data = dhp;
923 		} else if ((addr + len) >= (dhp->dh_uvaddr + dhp->dh_len)) {
924 			/*
925 			 * dhp is enclosed by <addr, addr+len>.
926 			 */
927 			dhp->dh_seg = nseg;
928 			nsdp->devmap_data = dhp;
929 			dhp = devmap_handle_unmap(dhp);
930 			nsdp->devmap_data = dhp; /* XX redundant? */
931 		} else if (((addr + len) > dhp->dh_uvaddr) &&
932 		    ((addr + len) < (dhp->dh_uvaddr + dhp->dh_len))) {
933 			mlen = addr + len - dhp->dh_uvaddr;
934 			if (callbackops->devmap_unmap != NULL)
935 				(*callbackops->devmap_unmap)(dhp, dhp->dh_pvtp,
936 				    dhp->dh_uoff, mlen, NULL,
937 				    NULL, dhp, &dhp->dh_pvtp);
938 			devmap_handle_reduce_len(dhp, mlen);
939 			nsdp->devmap_data = dhp;
940 			dhp->dh_seg = nseg;
941 			dhp = dhp->dh_next;
942 		} else {
943 			dhp->dh_seg = nseg;
944 			dhp = dhp->dh_next;
945 		}
946 	}
947 	return (0);
948 }
949 
950 /*
951  * Utility function handles reducing the length of a devmap handle during unmap
952  * Note that is only used for unmapping the front portion of the handler,
953  * i.e., we are bumping up the offset/pfn etc up by len
954  * Do not use if reducing length at the tail.
955  */
956 static void
957 devmap_handle_reduce_len(devmap_handle_t *dhp, size_t len)
958 {
959 	struct ddi_umem_cookie *cp;
960 	struct devmap_pmem_cookie *pcp;
961 	/*
962 	 * adjust devmap handle fields
963 	 */
964 	ASSERT(len < dhp->dh_len);
965 
966 	/* Make sure only page-aligned changes are done */
967 	ASSERT((len & PAGEOFFSET) == 0);
968 
969 	dhp->dh_len -= len;
970 	dhp->dh_uoff += (offset_t)len;
971 	dhp->dh_roff += (offset_t)len;
972 	dhp->dh_uvaddr += len;
973 	/* Need to grab dhp lock if REMAP */
974 	HOLD_DHP_LOCK(dhp);
975 	cp = dhp->dh_cookie;
976 	if (!(dhp->dh_flags & DEVMAP_MAPPING_INVALID)) {
977 		if (cookie_is_devmem(cp)) {
978 			dhp->dh_pfn += btop(len);
979 		} else if (cookie_is_pmem(cp)) {
980 			pcp = (struct devmap_pmem_cookie *)dhp->dh_pcookie;
981 			ASSERT((dhp->dh_roff & PAGEOFFSET) == 0 &&
982 			    dhp->dh_roff < ptob(pcp->dp_npages));
983 		} else {
984 			ASSERT(dhp->dh_roff < cp->size);
985 			ASSERT(dhp->dh_cvaddr >= cp->cvaddr &&
986 			    dhp->dh_cvaddr < (cp->cvaddr + cp->size));
987 			ASSERT((dhp->dh_cvaddr + len) <=
988 			    (cp->cvaddr + cp->size));
989 
990 			dhp->dh_cvaddr += len;
991 		}
992 	}
993 	/* XXX - Should recalculate the DEVMAP_FLAG_LARGE after changes */
994 	RELE_DHP_LOCK(dhp);
995 }
996 
997 /*
998  * Free devmap handle, dhp.
999  * Return the next devmap handle on the linked list.
1000  */
1001 static devmap_handle_t *
1002 devmap_handle_unmap(devmap_handle_t *dhp)
1003 {
1004 	struct devmap_callback_ctl *callbackops = &dhp->dh_callbackops;
1005 	struct segdev_data *sdp = (struct segdev_data *)dhp->dh_seg->s_data;
1006 	devmap_handle_t *dhpp = (devmap_handle_t *)sdp->devmap_data;
1007 
1008 	ASSERT(dhp != NULL);
1009 
1010 	/*
1011 	 * before we free up dhp, call the driver's devmap_unmap entry point
1012 	 * to free resources allocated for this dhp.
1013 	 */
1014 	if (callbackops->devmap_unmap != NULL) {
1015 		(*callbackops->devmap_unmap)(dhp, dhp->dh_pvtp, dhp->dh_uoff,
1016 		    dhp->dh_len, NULL, NULL, NULL, NULL);
1017 	}
1018 
1019 	if (dhpp == dhp) {	/* releasing first dhp, change sdp data */
1020 		sdp->devmap_data = dhp->dh_next;
1021 	} else {
1022 		while (dhpp->dh_next != dhp) {
1023 			dhpp = dhpp->dh_next;
1024 		}
1025 		dhpp->dh_next = dhp->dh_next;
1026 	}
1027 	dhpp = dhp->dh_next;	/* return value is next dhp in chain */
1028 
1029 	if (dhp->dh_softlock != NULL)
1030 		devmap_softlock_rele(dhp);
1031 
1032 	if (dhp->dh_ctx != NULL)
1033 		devmap_ctx_rele(dhp);
1034 
1035 	if (dhp->dh_flags & DEVMAP_LOCK_INITED) {
1036 		mutex_destroy(&dhp->dh_lock);
1037 	}
1038 	kmem_free(dhp, sizeof (devmap_handle_t));
1039 
1040 	return (dhpp);
1041 }
1042 
1043 /*
1044  * Free complete devmap handles from dhp for len bytes
1045  * dhp can be either the first handle or a subsequent handle
1046  */
1047 static void
1048 devmap_handle_unmap_head(devmap_handle_t *dhp, size_t len)
1049 {
1050 	struct devmap_callback_ctl *callbackops;
1051 
1052 	/*
1053 	 * free the devmap handles covered by len.
1054 	 */
1055 	while (len >= dhp->dh_len) {
1056 		len -= dhp->dh_len;
1057 		dhp = devmap_handle_unmap(dhp);
1058 	}
1059 	if (len != 0) {	/* partial unmap at head of first remaining dhp */
1060 		callbackops = &dhp->dh_callbackops;
1061 
1062 		/*
1063 		 * Call the unmap callback so the drivers can make
1064 		 * adjustment on its private data.
1065 		 */
1066 		if (callbackops->devmap_unmap != NULL)
1067 			(*callbackops->devmap_unmap)(dhp, dhp->dh_pvtp,
1068 			    dhp->dh_uoff, len, NULL, NULL, dhp, &dhp->dh_pvtp);
1069 		devmap_handle_reduce_len(dhp, len);
1070 	}
1071 }
1072 
1073 /*
1074  * Free devmap handles to truncate  the mapping after addr
1075  * RFE: Simpler to pass in dhp pointing at correct dhp (avoid find again)
1076  *	Also could then use the routine in middle unmap case too
1077  */
1078 static void
1079 devmap_handle_unmap_tail(devmap_handle_t *dhp, caddr_t addr)
1080 {
1081 	register struct seg *seg = dhp->dh_seg;
1082 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1083 	register devmap_handle_t *dhph = (devmap_handle_t *)sdp->devmap_data;
1084 	struct devmap_callback_ctl *callbackops;
1085 	register devmap_handle_t *dhpp;
1086 	size_t maplen;
1087 	ulong_t off;
1088 	size_t len;
1089 
1090 	maplen = (size_t)(addr - dhp->dh_uvaddr);
1091 	dhph = devmap_find_handle(dhph, addr);
1092 
1093 	while (dhph != NULL) {
1094 		if (maplen == 0) {
1095 			dhph =  devmap_handle_unmap(dhph);
1096 		} else {
1097 			callbackops = &dhph->dh_callbackops;
1098 			len = dhph->dh_len - maplen;
1099 			off = (ulong_t)sdp->offset + (addr - seg->s_base);
1100 			/*
1101 			 * Call the unmap callback so the driver
1102 			 * can make adjustments on its private data.
1103 			 */
1104 			if (callbackops->devmap_unmap != NULL)
1105 				(*callbackops->devmap_unmap)(dhph,
1106 				    dhph->dh_pvtp, off, len,
1107 				    (devmap_cookie_t *)dhph,
1108 				    &dhph->dh_pvtp, NULL, NULL);
1109 			/* XXX Reducing len needs to recalculate LARGE flag */
1110 			dhph->dh_len = maplen;
1111 			maplen = 0;
1112 			dhpp = dhph->dh_next;
1113 			dhph->dh_next = NULL;
1114 			dhph = dhpp;
1115 		}
1116 	} /* end while */
1117 }
1118 
1119 /*
1120  * Free a segment.
1121  */
1122 static void
1123 segdev_free(struct seg *seg)
1124 {
1125 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1126 	devmap_handle_t *dhp = (devmap_handle_t *)sdp->devmap_data;
1127 
1128 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_FREE,
1129 	    "segdev_free: dhp=%p seg=%p", (void *)dhp, (void *)seg);
1130 	DEBUGF(3, (CE_CONT, "segdev_free: dhp %p seg %p\n",
1131 	    (void *)dhp, (void *)seg));
1132 
1133 	/*
1134 	 * Since the address space is "write" locked, we
1135 	 * don't need the segment lock to protect "segdev" data.
1136 	 */
1137 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1138 
1139 	while (dhp != NULL)
1140 		dhp = devmap_handle_unmap(dhp);
1141 
1142 	VN_RELE(sdp->vp);
1143 	if (sdp->vpage != NULL)
1144 		kmem_free(sdp->vpage, vpgtob(seg_pages(seg)));
1145 
1146 	rw_destroy(&sdp->lock);
1147 	kmem_free(sdp, sizeof (*sdp));
1148 }
1149 
1150 static void
1151 free_devmap_handle(devmap_handle_t *dhp)
1152 {
1153 	register devmap_handle_t *dhpp;
1154 
1155 	/*
1156 	 * free up devmap handle
1157 	 */
1158 	while (dhp != NULL) {
1159 		dhpp = dhp->dh_next;
1160 		if (dhp->dh_flags & DEVMAP_LOCK_INITED) {
1161 			mutex_destroy(&dhp->dh_lock);
1162 		}
1163 
1164 		if (dhp->dh_softlock != NULL)
1165 			devmap_softlock_rele(dhp);
1166 
1167 		if (dhp->dh_ctx != NULL)
1168 			devmap_ctx_rele(dhp);
1169 
1170 		kmem_free(dhp, sizeof (devmap_handle_t));
1171 		dhp = dhpp;
1172 	}
1173 }
1174 
1175 /*
1176  * routines to lock and unlock underlying segkp segment for
1177  * KMEM_PAGEABLE type cookies.
1178  * segkp only allows a single pending F_SOFTLOCK
1179  * we keep track of number of locks in the cookie so we can
1180  * have multiple pending faults and manage the calls to segkp.
1181  * RFE: if segkp supports either pagelock or can support multiple
1182  * calls to F_SOFTLOCK, then these routines can go away.
1183  *	If pagelock, segdev_faultpage can fault on a page by page basis
1184  *		and simplifies the code quite a bit.
1185  *	if multiple calls allowed but not partial ranges, then need for
1186  *	cookie->lock and locked count goes away, code can call as_fault directly
1187  */
1188 static faultcode_t
1189 acquire_kpmem_lock(struct ddi_umem_cookie *cookie, size_t npages)
1190 {
1191 	int err = 0;
1192 	ASSERT(cookie_is_kpmem(cookie));
1193 	/*
1194 	 * Fault in pages in segkp with F_SOFTLOCK.
1195 	 * We want to hold the lock until all pages have been loaded.
1196 	 * segkp only allows single caller to hold SOFTLOCK, so cookie
1197 	 * holds a count so we dont call into segkp multiple times
1198 	 */
1199 	mutex_enter(&cookie->lock);
1200 
1201 	/*
1202 	 * Check for overflow in locked field
1203 	 */
1204 	if ((UINT32_MAX - cookie->locked) < npages) {
1205 		err = FC_MAKE_ERR(ENOMEM);
1206 	} else if (cookie->locked == 0) {
1207 		/* First time locking */
1208 		err = as_fault(kas.a_hat, &kas, cookie->cvaddr,
1209 		    cookie->size, F_SOFTLOCK, PROT_READ|PROT_WRITE);
1210 	}
1211 	if (!err) {
1212 		cookie->locked += npages;
1213 	}
1214 	mutex_exit(&cookie->lock);
1215 	return (err);
1216 }
1217 
1218 static void
1219 release_kpmem_lock(struct ddi_umem_cookie *cookie, size_t npages)
1220 {
1221 	mutex_enter(&cookie->lock);
1222 	ASSERT(cookie_is_kpmem(cookie));
1223 	ASSERT(cookie->locked >= npages);
1224 	cookie->locked -= (uint_t)npages;
1225 	if (cookie->locked == 0) {
1226 		/* Last unlock */
1227 		if (as_fault(kas.a_hat, &kas, cookie->cvaddr,
1228 		    cookie->size, F_SOFTUNLOCK, PROT_READ|PROT_WRITE))
1229 			panic("segdev releasing kpmem lock %p", (void *)cookie);
1230 	}
1231 	mutex_exit(&cookie->lock);
1232 }
1233 
1234 /*
1235  * Routines to synchronize F_SOFTLOCK and F_INVAL faults for
1236  * drivers with devmap_access callbacks
1237  * slock->softlocked basically works like a rw lock
1238  *	-ve counts => F_SOFTLOCK in progress
1239  *	+ve counts => F_INVAL/F_PROT in progress
1240  * We allow only one F_SOFTLOCK at a time
1241  * but can have multiple pending F_INVAL/F_PROT calls
1242  *
1243  * This routine waits using cv_wait_sig so killing processes is more graceful
1244  * Returns EINTR if coming out of this routine due to a signal, 0 otherwise
1245  */
1246 static int devmap_softlock_enter(
1247 	struct devmap_softlock *slock,
1248 	size_t npages,
1249 	enum fault_type type)
1250 {
1251 	if (npages == 0)
1252 		return (0);
1253 	mutex_enter(&(slock->lock));
1254 	switch (type) {
1255 	case F_SOFTLOCK :
1256 		while (slock->softlocked) {
1257 			if (cv_wait_sig(&(slock)->cv, &(slock)->lock) == 0) {
1258 				/* signalled */
1259 				mutex_exit(&(slock->lock));
1260 				return (EINTR);
1261 			}
1262 		}
1263 		slock->softlocked -= npages; /* -ve count => locked */
1264 		break;
1265 	case F_INVAL :
1266 	case F_PROT :
1267 		while (slock->softlocked < 0)
1268 			if (cv_wait_sig(&(slock)->cv, &(slock)->lock) == 0) {
1269 				/* signalled */
1270 				mutex_exit(&(slock->lock));
1271 				return (EINTR);
1272 			}
1273 		slock->softlocked += npages; /* +ve count => f_invals */
1274 		break;
1275 	default:
1276 		ASSERT(0);
1277 	}
1278 	mutex_exit(&(slock->lock));
1279 	return (0);
1280 }
1281 
1282 static void devmap_softlock_exit(
1283 	struct devmap_softlock *slock,
1284 	size_t npages,
1285 	enum fault_type type)
1286 {
1287 	if (slock == NULL)
1288 		return;
1289 	mutex_enter(&(slock->lock));
1290 	switch (type) {
1291 	case F_SOFTLOCK :
1292 		ASSERT(-slock->softlocked >= npages);
1293 		slock->softlocked += npages;	/* -ve count is softlocked */
1294 		if (slock->softlocked == 0)
1295 			cv_signal(&slock->cv);
1296 		break;
1297 	case F_INVAL :
1298 	case F_PROT:
1299 		ASSERT(slock->softlocked >= npages);
1300 		slock->softlocked -= npages;
1301 		if (slock->softlocked == 0)
1302 			cv_signal(&slock->cv);
1303 		break;
1304 	default:
1305 		ASSERT(0);
1306 	}
1307 	mutex_exit(&(slock->lock));
1308 }
1309 
1310 /*
1311  * Do a F_SOFTUNLOCK call over the range requested.
1312  * The range must have already been F_SOFTLOCK'ed.
1313  * The segment lock should be held, (but not the segment private lock?)
1314  *  The softunlock code below does not adjust for large page sizes
1315  *	assumes the caller already did any addr/len adjustments for
1316  *	pagesize mappings before calling.
1317  */
1318 /*ARGSUSED*/
1319 static void
1320 segdev_softunlock(
1321 	struct hat *hat,		/* the hat */
1322 	struct seg *seg,		/* seg_dev of interest */
1323 	caddr_t addr,			/* base address of range */
1324 	size_t len,			/* number of bytes */
1325 	enum seg_rw rw)			/* type of access at fault */
1326 {
1327 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1328 	devmap_handle_t *dhp_head = (devmap_handle_t *)sdp->devmap_data;
1329 
1330 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_SOFTUNLOCK,
1331 	    "segdev_softunlock:dhp_head=%p sdp=%p addr=%p len=%lx",
1332 	    dhp_head, sdp, addr, len);
1333 	DEBUGF(3, (CE_CONT, "segdev_softunlock: dhp %p lockcnt %lx "
1334 	    "addr %p len %lx\n",
1335 	    (void *)dhp_head, sdp->softlockcnt, (void *)addr, len));
1336 
1337 	hat_unlock(hat, addr, len);
1338 
1339 	if (dhp_head != NULL) {
1340 		devmap_handle_t *dhp;
1341 		size_t mlen;
1342 		size_t tlen = len;
1343 		ulong_t off;
1344 
1345 		dhp = devmap_find_handle(dhp_head, addr);
1346 		ASSERT(dhp != NULL);
1347 
1348 		off = (ulong_t)(addr - dhp->dh_uvaddr);
1349 		while (tlen != 0) {
1350 			mlen = MIN(tlen, (dhp->dh_len - off));
1351 
1352 			/*
1353 			 * unlock segkp memory, locked during F_SOFTLOCK
1354 			 */
1355 			if (dhp_is_kpmem(dhp)) {
1356 				release_kpmem_lock(
1357 				    (struct ddi_umem_cookie *)dhp->dh_cookie,
1358 				    btopr(mlen));
1359 			}
1360 
1361 			/*
1362 			 * Do the softlock accounting for devmap_access
1363 			 */
1364 			if (dhp->dh_callbackops.devmap_access != NULL) {
1365 				devmap_softlock_exit(dhp->dh_softlock,
1366 				    btopr(mlen), F_SOFTLOCK);
1367 			}
1368 
1369 			tlen -= mlen;
1370 			dhp = dhp->dh_next;
1371 			off = 0;
1372 		}
1373 	}
1374 
1375 	mutex_enter(&freemem_lock);
1376 	ASSERT(sdp->softlockcnt >= btopr(len));
1377 	sdp->softlockcnt -= btopr(len);
1378 	mutex_exit(&freemem_lock);
1379 	if (sdp->softlockcnt == 0) {
1380 		/*
1381 		 * All SOFTLOCKS are gone. Wakeup any waiting
1382 		 * unmappers so they can try again to unmap.
1383 		 * Check for waiters first without the mutex
1384 		 * held so we don't always grab the mutex on
1385 		 * softunlocks.
1386 		 */
1387 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1388 			mutex_enter(&seg->s_as->a_contents);
1389 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1390 				AS_CLRUNMAPWAIT(seg->s_as);
1391 				cv_broadcast(&seg->s_as->a_cv);
1392 			}
1393 			mutex_exit(&seg->s_as->a_contents);
1394 		}
1395 	}
1396 
1397 }
1398 
1399 /*
1400  * Handle fault for a single page.
1401  * Done in a separate routine so we can handle errors more easily.
1402  * This routine is called only from segdev_faultpages()
1403  * when looping over the range of addresses requested. The segment lock is held.
1404  */
1405 static faultcode_t
1406 segdev_faultpage(
1407 	struct hat *hat,		/* the hat */
1408 	struct seg *seg,		/* seg_dev of interest */
1409 	caddr_t addr,			/* address in as */
1410 	struct vpage *vpage,		/* pointer to vpage for seg, addr */
1411 	enum fault_type type,		/* type of fault */
1412 	enum seg_rw rw,			/* type of access at fault */
1413 	devmap_handle_t *dhp)		/* devmap handle if any for this page */
1414 {
1415 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1416 	uint_t prot;
1417 	pfn_t pfnum = PFN_INVALID;
1418 	u_offset_t offset;
1419 	uint_t hat_flags;
1420 	dev_info_t *dip;
1421 
1422 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_FAULTPAGE,
1423 	    "segdev_faultpage: dhp=%p seg=%p addr=%p", dhp, seg, addr);
1424 	DEBUGF(8, (CE_CONT, "segdev_faultpage: dhp %p seg %p addr %p \n",
1425 	    (void *)dhp, (void *)seg, (void *)addr));
1426 
1427 	/*
1428 	 * Initialize protection value for this page.
1429 	 * If we have per page protection values check it now.
1430 	 */
1431 	if (sdp->pageprot) {
1432 		uint_t protchk;
1433 
1434 		switch (rw) {
1435 		case S_READ:
1436 			protchk = PROT_READ;
1437 			break;
1438 		case S_WRITE:
1439 			protchk = PROT_WRITE;
1440 			break;
1441 		case S_EXEC:
1442 			protchk = PROT_EXEC;
1443 			break;
1444 		case S_OTHER:
1445 		default:
1446 			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
1447 			break;
1448 		}
1449 
1450 		prot = VPP_PROT(vpage);
1451 		if ((prot & protchk) == 0)
1452 			return (FC_PROT);	/* illegal access type */
1453 	} else {
1454 		prot = sdp->prot;
1455 		/* caller has already done segment level protection check */
1456 	}
1457 
1458 	if (type == F_SOFTLOCK) {
1459 		mutex_enter(&freemem_lock);
1460 		sdp->softlockcnt++;
1461 		mutex_exit(&freemem_lock);
1462 	}
1463 
1464 	hat_flags = ((type == F_SOFTLOCK) ? HAT_LOAD_LOCK : HAT_LOAD);
1465 	offset = sdp->offset + (u_offset_t)(addr - seg->s_base);
1466 	/*
1467 	 * In the devmap framework, sdp->mapfunc is set to NULL.  we can get
1468 	 * pfnum from dhp->dh_pfn (at beginning of segment) and offset from
1469 	 * seg->s_base.
1470 	 */
1471 	if (dhp == NULL) {
1472 		/* If segment has devmap_data, then dhp should be non-NULL */
1473 		ASSERT(sdp->devmap_data == NULL);
1474 		pfnum = (pfn_t)cdev_mmap(sdp->mapfunc, sdp->vp->v_rdev,
1475 		    (off_t)offset, prot);
1476 		prot |= sdp->hat_attr;
1477 	} else {
1478 		ulong_t off;
1479 		struct ddi_umem_cookie *cp;
1480 		struct devmap_pmem_cookie *pcp;
1481 
1482 		/* ensure the dhp passed in contains addr. */
1483 		ASSERT(dhp == devmap_find_handle(
1484 		    (devmap_handle_t *)sdp->devmap_data, addr));
1485 
1486 		off = addr - dhp->dh_uvaddr;
1487 
1488 		/*
1489 		 * This routine assumes that the caller makes sure that the
1490 		 * fields in dhp used below are unchanged due to remap during
1491 		 * this call. Caller does HOLD_DHP_LOCK if neeed
1492 		 */
1493 		cp = dhp->dh_cookie;
1494 		if (dhp->dh_flags & DEVMAP_MAPPING_INVALID) {
1495 			pfnum = PFN_INVALID;
1496 		} else if (cookie_is_devmem(cp)) {
1497 			pfnum = dhp->dh_pfn + btop(off);
1498 		} else if (cookie_is_pmem(cp)) {
1499 			pcp = (struct devmap_pmem_cookie *)dhp->dh_pcookie;
1500 			ASSERT((dhp->dh_roff & PAGEOFFSET) == 0 &&
1501 			    dhp->dh_roff < ptob(pcp->dp_npages));
1502 			pfnum = page_pptonum(
1503 			    pcp->dp_pparray[btop(off + dhp->dh_roff)]);
1504 		} else {
1505 			ASSERT(dhp->dh_roff < cp->size);
1506 			ASSERT(dhp->dh_cvaddr >= cp->cvaddr &&
1507 			    dhp->dh_cvaddr < (cp->cvaddr + cp->size));
1508 			ASSERT((dhp->dh_cvaddr + off) <=
1509 			    (cp->cvaddr + cp->size));
1510 			ASSERT((dhp->dh_cvaddr + off + PAGESIZE) <=
1511 			    (cp->cvaddr + cp->size));
1512 
1513 			switch (cp->type) {
1514 			case UMEM_LOCKED :
1515 				if (cp->pparray != NULL) {
1516 					ASSERT((dhp->dh_roff &
1517 					    PAGEOFFSET) == 0);
1518 					pfnum = page_pptonum(
1519 					    cp->pparray[btop(off +
1520 					    dhp->dh_roff)]);
1521 				} else {
1522 					pfnum = hat_getpfnum(
1523 					    ((proc_t *)cp->procp)->p_as->a_hat,
1524 					    cp->cvaddr + off);
1525 				}
1526 			break;
1527 			case UMEM_TRASH :
1528 				pfnum = page_pptonum(trashpp);
1529 				/*
1530 				 * We should set hat_flags to HAT_NOFAULT also
1531 				 * However, not all hat layers implement this
1532 				 */
1533 				break;
1534 			case KMEM_PAGEABLE:
1535 			case KMEM_NON_PAGEABLE:
1536 				pfnum = hat_getpfnum(kas.a_hat,
1537 				    dhp->dh_cvaddr + off);
1538 				break;
1539 			default :
1540 				pfnum = PFN_INVALID;
1541 				break;
1542 			}
1543 		}
1544 		prot |= dhp->dh_hat_attr;
1545 	}
1546 	if (pfnum == PFN_INVALID) {
1547 		return (FC_MAKE_ERR(EFAULT));
1548 	}
1549 	/* prot should already be OR'ed in with hat_attributes if needed */
1550 
1551 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_FAULTPAGE_CK1,
1552 	    "segdev_faultpage: pfnum=%lx memory=%x prot=%x flags=%x",
1553 	    pfnum, pf_is_memory(pfnum), prot, hat_flags);
1554 	DEBUGF(9, (CE_CONT, "segdev_faultpage: pfnum %lx memory %x "
1555 	    "prot %x flags %x\n", pfnum, pf_is_memory(pfnum), prot, hat_flags));
1556 
1557 	if (pf_is_memory(pfnum) || (dhp != NULL)) {
1558 		/*
1559 		 * It's not _really_ required here to pass sdp->hat_flags
1560 		 * to hat_devload even though we do it.
1561 		 * This is because hat figures it out DEVMEM mappings
1562 		 * are non-consistent, anyway.
1563 		 */
1564 		hat_devload(hat, addr, PAGESIZE, pfnum,
1565 		    prot, hat_flags | sdp->hat_flags);
1566 		return (0);
1567 	}
1568 
1569 	/*
1570 	 * Fall through to the case where devmap is not used and need to call
1571 	 * up the device tree to set up the mapping
1572 	 */
1573 
1574 	dip = VTOS(VTOCVP(sdp->vp))->s_dip;
1575 	ASSERT(dip);
1576 
1577 	/*
1578 	 * When calling ddi_map_fault, we do not OR in sdp->hat_attr
1579 	 * This is because this calls drivers which may not expect
1580 	 * prot to have any other values than PROT_ALL
1581 	 * The root nexus driver has a hack to peek into the segment
1582 	 * structure and then OR in sdp->hat_attr.
1583 	 * XX In case the bus_ops interfaces are ever revisited
1584 	 * we need to fix this. prot should include other hat attributes
1585 	 */
1586 	if (ddi_map_fault(dip, hat, seg, addr, NULL, pfnum, prot & PROT_ALL,
1587 	    (uint_t)(type == F_SOFTLOCK)) != DDI_SUCCESS) {
1588 		return (FC_MAKE_ERR(EFAULT));
1589 	}
1590 	return (0);
1591 }
1592 
1593 static faultcode_t
1594 segdev_fault(
1595 	struct hat *hat,		/* the hat */
1596 	struct seg *seg,		/* the seg_dev of interest */
1597 	caddr_t addr,			/* the address of the fault */
1598 	size_t len,			/* the length of the range */
1599 	enum fault_type type,		/* type of fault */
1600 	enum seg_rw rw)			/* type of access at fault */
1601 {
1602 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1603 	devmap_handle_t *dhp_head = (devmap_handle_t *)sdp->devmap_data;
1604 	devmap_handle_t *dhp;
1605 	struct devmap_softlock *slock = NULL;
1606 	ulong_t slpage = 0;
1607 	ulong_t off;
1608 	caddr_t maddr = addr;
1609 	int err;
1610 	int err_is_faultcode = 0;
1611 
1612 	TRACE_5(TR_FAC_DEVMAP, TR_DEVMAP_FAULT,
1613 	    "segdev_fault: dhp_head=%p seg=%p addr=%p len=%lx type=%x",
1614 	    (void *)dhp_head, (void *)seg, (void *)addr, len, type);
1615 	DEBUGF(7, (CE_CONT, "segdev_fault: dhp_head %p seg %p "
1616 	    "addr %p len %lx type %x\n",
1617 	    (void *)dhp_head, (void *)seg, (void *)addr, len, type));
1618 
1619 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1620 
1621 	/* Handle non-devmap case */
1622 	if (dhp_head == NULL)
1623 		return (segdev_faultpages(hat, seg, addr, len, type, rw, NULL));
1624 
1625 	/* Find devmap handle */
1626 	if ((dhp = devmap_find_handle(dhp_head, addr)) == NULL)
1627 		return (FC_NOMAP);
1628 
1629 	/*
1630 	 * The seg_dev driver does not implement copy-on-write,
1631 	 * and always loads translations with maximal allowed permissions
1632 	 * but we got an fault trying to access the device.
1633 	 * Servicing the fault is not going to result in any better result
1634 	 * RFE: If we want devmap_access callbacks to be involved in F_PROT
1635 	 *	faults, then the code below is written for that
1636 	 *	Pending resolution of the following:
1637 	 *	- determine if the F_INVAL/F_SOFTLOCK syncing
1638 	 *	is needed for F_PROT also or not. The code below assumes it does
1639 	 *	- If driver sees F_PROT and calls devmap_load with same type,
1640 	 *	then segdev_faultpages will fail with FC_PROT anyway, need to
1641 	 *	change that so calls from devmap_load to segdev_faultpages for
1642 	 *	F_PROT type are retagged to F_INVAL.
1643 	 * RFE: Today we dont have drivers that use devmap and want to handle
1644 	 *	F_PROT calls. The code in segdev_fault* is written to allow
1645 	 *	this case but is not tested. A driver that needs this capability
1646 	 *	should be able to remove the short-circuit case; resolve the
1647 	 *	above issues and "should" work.
1648 	 */
1649 	if (type == F_PROT) {
1650 		return (FC_PROT);
1651 	}
1652 
1653 	/*
1654 	 * Loop through dhp list calling devmap_access or segdev_faultpages for
1655 	 * each devmap handle.
1656 	 * drivers which implement devmap_access can interpose on faults and do
1657 	 * device-appropriate special actions before calling devmap_load.
1658 	 */
1659 
1660 	/*
1661 	 * Unfortunately, this simple loop has turned out to expose a variety
1662 	 * of complex problems which results in the following convoluted code.
1663 	 *
1664 	 * First, a desire to handle a serialization of F_SOFTLOCK calls
1665 	 * to the driver within the framework.
1666 	 *	This results in a dh_softlock structure that is on a per device
1667 	 *	(or device instance) basis and serializes devmap_access calls.
1668 	 *	Ideally we would need to do this for underlying
1669 	 *	memory/device regions that are being faulted on
1670 	 *	but that is hard to identify and with REMAP, harder
1671 	 * Second, a desire to serialize F_INVAL(and F_PROT) calls w.r.t.
1672 	 * 	to F_SOFTLOCK calls to the driver.
1673 	 * These serializations are to simplify the driver programmer model.
1674 	 * To support these two features, the code first goes through the
1675 	 *	devmap handles and counts the pages (slpage) that are covered
1676 	 *	by devmap_access callbacks.
1677 	 * This part ends with a devmap_softlock_enter call
1678 	 *	which allows only one F_SOFTLOCK active on a device instance,
1679 	 *	but multiple F_INVAL/F_PROTs can be active except when a
1680 	 *	F_SOFTLOCK is active
1681 	 *
1682 	 * Next, we dont short-circuit the fault code upfront to call
1683 	 *	segdev_softunlock for F_SOFTUNLOCK, because we must use
1684 	 *	the same length when we softlock and softunlock.
1685 	 *
1686 	 *	-Hat layers may not support softunlocking lengths less than the
1687 	 *	original length when there is large page support.
1688 	 *	-kpmem locking is dependent on keeping the lengths same.
1689 	 *	-if drivers handled F_SOFTLOCK, they probably also expect to
1690 	 *		see an F_SOFTUNLOCK of the same length
1691 	 *	Hence, if extending lengths during softlock,
1692 	 *	softunlock has to make the same adjustments and goes through
1693 	 *	the same loop calling segdev_faultpages/segdev_softunlock
1694 	 *	But some of the synchronization and error handling is different
1695 	 */
1696 
1697 	if (type != F_SOFTUNLOCK) {
1698 		devmap_handle_t *dhpp = dhp;
1699 		size_t slen = len;
1700 
1701 		/*
1702 		 * Calculate count of pages that are :
1703 		 * a) within the (potentially extended) fault region
1704 		 * b) AND covered by devmap handle with devmap_access
1705 		 */
1706 		off = (ulong_t)(addr - dhpp->dh_uvaddr);
1707 		while (slen != 0) {
1708 			size_t mlen;
1709 
1710 			/*
1711 			 * Softlocking on a region that allows remap is
1712 			 * unsupported due to unresolved locking issues
1713 			 * XXX: unclear what these are?
1714 			 *	One potential is that if there is a pending
1715 			 *	softlock, then a remap should not be allowed
1716 			 *	until the unlock is done. This is easily
1717 			 *	fixed by returning error in devmap*remap on
1718 			 *	checking the dh->dh_softlock->softlocked value
1719 			 */
1720 			if ((type == F_SOFTLOCK) &&
1721 			    (dhpp->dh_flags & DEVMAP_ALLOW_REMAP)) {
1722 				return (FC_NOSUPPORT);
1723 			}
1724 
1725 			mlen = MIN(slen, (dhpp->dh_len - off));
1726 			if (dhpp->dh_callbackops.devmap_access) {
1727 				size_t llen;
1728 				caddr_t laddr;
1729 				/*
1730 				 * use extended length for large page mappings
1731 				 */
1732 				HOLD_DHP_LOCK(dhpp);
1733 				if ((sdp->pageprot == 0) &&
1734 				    (dhpp->dh_flags & DEVMAP_FLAG_LARGE)) {
1735 					devmap_get_large_pgsize(dhpp,
1736 					    mlen, maddr, &llen, &laddr);
1737 				} else {
1738 					llen = mlen;
1739 				}
1740 				RELE_DHP_LOCK(dhpp);
1741 
1742 				slpage += btopr(llen);
1743 				slock = dhpp->dh_softlock;
1744 			}
1745 			maddr += mlen;
1746 			ASSERT(slen >= mlen);
1747 			slen -= mlen;
1748 			dhpp = dhpp->dh_next;
1749 			off = 0;
1750 		}
1751 		/*
1752 		 * synchonize with other faulting threads and wait till safe
1753 		 * devmap_softlock_enter might return due to signal in cv_wait
1754 		 *
1755 		 * devmap_softlock_enter has to be called outside of while loop
1756 		 * to prevent a deadlock if len spans over multiple dhps.
1757 		 * dh_softlock is based on device instance and if multiple dhps
1758 		 * use the same device instance, the second dhp's LOCK call
1759 		 * will hang waiting on the first to complete.
1760 		 * devmap_setup verifies that slocks in a dhp_chain are same.
1761 		 * RFE: this deadlock only hold true for F_SOFTLOCK. For
1762 		 * 	F_INVAL/F_PROT, since we now allow multiple in parallel,
1763 		 *	we could have done the softlock_enter inside the loop
1764 		 *	and supported multi-dhp mappings with dissimilar devices
1765 		 */
1766 		if (err = devmap_softlock_enter(slock, slpage, type))
1767 			return (FC_MAKE_ERR(err));
1768 	}
1769 
1770 	/* reset 'maddr' to the start addr of the range of fault. */
1771 	maddr = addr;
1772 
1773 	/* calculate the offset corresponds to 'addr' in the first dhp. */
1774 	off = (ulong_t)(addr - dhp->dh_uvaddr);
1775 
1776 	/*
1777 	 * The fault length may span over multiple dhps.
1778 	 * Loop until the total length is satisfied.
1779 	 */
1780 	while (len != 0) {
1781 		size_t llen;
1782 		size_t mlen;
1783 		caddr_t laddr;
1784 
1785 		/*
1786 		 * mlen is the smaller of 'len' and the length
1787 		 * from addr to the end of mapping defined by dhp.
1788 		 */
1789 		mlen = MIN(len, (dhp->dh_len - off));
1790 
1791 		HOLD_DHP_LOCK(dhp);
1792 		/*
1793 		 * Pass the extended length and address to devmap_access
1794 		 * if large pagesize is used for loading address translations.
1795 		 */
1796 		if ((sdp->pageprot == 0) &&
1797 		    (dhp->dh_flags & DEVMAP_FLAG_LARGE)) {
1798 			devmap_get_large_pgsize(dhp, mlen, maddr,
1799 			    &llen, &laddr);
1800 			ASSERT(maddr == addr || laddr == maddr);
1801 		} else {
1802 			llen = mlen;
1803 			laddr = maddr;
1804 		}
1805 
1806 		if (dhp->dh_callbackops.devmap_access != NULL) {
1807 			offset_t aoff;
1808 
1809 			aoff = sdp->offset + (offset_t)(laddr - seg->s_base);
1810 
1811 			/*
1812 			 * call driver's devmap_access entry point which will
1813 			 * call devmap_load/contextmgmt to load the translations
1814 			 *
1815 			 * We drop the dhp_lock before calling access so
1816 			 * drivers can call devmap_*_remap within access
1817 			 */
1818 			RELE_DHP_LOCK(dhp);
1819 
1820 			err = (*dhp->dh_callbackops.devmap_access)(
1821 			    dhp, (void *)dhp->dh_pvtp, aoff, llen, type, rw);
1822 		} else {
1823 			/*
1824 			 * If no devmap_access entry point, then load mappings
1825 			 * hold dhp_lock across faultpages if REMAP
1826 			 */
1827 			err = segdev_faultpages(hat, seg, laddr, llen,
1828 			    type, rw, dhp);
1829 			err_is_faultcode = 1;
1830 			RELE_DHP_LOCK(dhp);
1831 		}
1832 
1833 		if (err) {
1834 			if ((type == F_SOFTLOCK) && (maddr > addr)) {
1835 				/*
1836 				 * If not first dhp, use
1837 				 * segdev_fault(F_SOFTUNLOCK) for prior dhps
1838 				 * While this is recursion, it is incorrect to
1839 				 * call just segdev_softunlock
1840 				 * if we are using either large pages
1841 				 * or devmap_access. It will be more right
1842 				 * to go through the same loop as above
1843 				 * rather than call segdev_softunlock directly
1844 				 * It will use the right lenghths as well as
1845 				 * call into the driver devmap_access routines.
1846 				 */
1847 				size_t done = (size_t)(maddr - addr);
1848 				(void) segdev_fault(hat, seg, addr, done,
1849 				    F_SOFTUNLOCK, S_OTHER);
1850 				/*
1851 				 * reduce slpage by number of pages
1852 				 * released by segdev_softunlock
1853 				 */
1854 				ASSERT(slpage >= btopr(done));
1855 				devmap_softlock_exit(slock,
1856 				    slpage - btopr(done), type);
1857 			} else {
1858 				devmap_softlock_exit(slock, slpage, type);
1859 			}
1860 
1861 
1862 			/*
1863 			 * Segdev_faultpages() already returns a faultcode,
1864 			 * hence, result from segdev_faultpages() should be
1865 			 * returned directly.
1866 			 */
1867 			if (err_is_faultcode)
1868 				return (err);
1869 			return (FC_MAKE_ERR(err));
1870 		}
1871 
1872 		maddr += mlen;
1873 		ASSERT(len >= mlen);
1874 		len -= mlen;
1875 		dhp = dhp->dh_next;
1876 		off = 0;
1877 
1878 		ASSERT(!dhp || len == 0 || maddr == dhp->dh_uvaddr);
1879 	}
1880 	/*
1881 	 * release the softlock count at end of fault
1882 	 * For F_SOFTLOCk this is done in the later F_SOFTUNLOCK
1883 	 */
1884 	if ((type == F_INVAL) || (type == F_PROT))
1885 		devmap_softlock_exit(slock, slpage, type);
1886 	return (0);
1887 }
1888 
1889 /*
1890  * segdev_faultpages
1891  *
1892  * Used to fault in seg_dev segment pages. Called by segdev_fault or devmap_load
1893  * This routine assumes that the callers makes sure that the fields
1894  * in dhp used below are not changed due to remap during this call.
1895  * Caller does HOLD_DHP_LOCK if neeed
1896  * This routine returns a faultcode_t as a return value for segdev_fault.
1897  */
1898 static faultcode_t
1899 segdev_faultpages(
1900 	struct hat *hat,		/* the hat */
1901 	struct seg *seg,		/* the seg_dev of interest */
1902 	caddr_t addr,			/* the address of the fault */
1903 	size_t len,			/* the length of the range */
1904 	enum fault_type type,		/* type of fault */
1905 	enum seg_rw rw,			/* type of access at fault */
1906 	devmap_handle_t *dhp)		/* devmap handle */
1907 {
1908 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
1909 	register caddr_t a;
1910 	struct vpage *vpage;
1911 	struct ddi_umem_cookie *kpmem_cookie = NULL;
1912 	int err;
1913 
1914 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_FAULTPAGES,
1915 	    "segdev_faultpages: dhp=%p seg=%p addr=%p len=%lx",
1916 	    (void *)dhp, (void *)seg, (void *)addr, len);
1917 	DEBUGF(5, (CE_CONT, "segdev_faultpages: "
1918 	    "dhp %p seg %p addr %p len %lx\n",
1919 	    (void *)dhp, (void *)seg, (void *)addr, len));
1920 
1921 	/*
1922 	 * The seg_dev driver does not implement copy-on-write,
1923 	 * and always loads translations with maximal allowed permissions
1924 	 * but we got an fault trying to access the device.
1925 	 * Servicing the fault is not going to result in any better result
1926 	 * XXX: If we want to allow devmap_access to handle F_PROT calls,
1927 	 * This code should be removed and let the normal fault handling
1928 	 * take care of finding the error
1929 	 */
1930 	if (type == F_PROT) {
1931 		return (FC_PROT);
1932 	}
1933 
1934 	if (type == F_SOFTUNLOCK) {
1935 		segdev_softunlock(hat, seg, addr, len, rw);
1936 		return (0);
1937 	}
1938 
1939 	/*
1940 	 * For kernel pageable memory, fault/lock segkp pages
1941 	 * We hold this until the completion of this
1942 	 * fault (INVAL/PROT) or till unlock (SOFTLOCK).
1943 	 */
1944 	if ((dhp != NULL) && dhp_is_kpmem(dhp)) {
1945 		kpmem_cookie = (struct ddi_umem_cookie *)dhp->dh_cookie;
1946 		if (err = acquire_kpmem_lock(kpmem_cookie, btopr(len)))
1947 			return (err);
1948 	}
1949 
1950 	/*
1951 	 * If we have the same protections for the entire segment,
1952 	 * insure that the access being attempted is legitimate.
1953 	 */
1954 	rw_enter(&sdp->lock, RW_READER);
1955 	if (sdp->pageprot == 0) {
1956 		uint_t protchk;
1957 
1958 		switch (rw) {
1959 		case S_READ:
1960 			protchk = PROT_READ;
1961 			break;
1962 		case S_WRITE:
1963 			protchk = PROT_WRITE;
1964 			break;
1965 		case S_EXEC:
1966 			protchk = PROT_EXEC;
1967 			break;
1968 		case S_OTHER:
1969 		default:
1970 			protchk = PROT_READ | PROT_WRITE | PROT_EXEC;
1971 			break;
1972 		}
1973 
1974 		if ((sdp->prot & protchk) == 0) {
1975 			rw_exit(&sdp->lock);
1976 			/* undo kpmem locking */
1977 			if (kpmem_cookie != NULL) {
1978 				release_kpmem_lock(kpmem_cookie, btopr(len));
1979 			}
1980 			return (FC_PROT);	/* illegal access type */
1981 		}
1982 	}
1983 
1984 	/*
1985 	 * we do a single hat_devload for the range if
1986 	 *   - devmap framework (dhp is not NULL),
1987 	 *   - pageprot == 0, i.e., no per-page protection set and
1988 	 *   - is device pages, irrespective of whether we are using large pages
1989 	 */
1990 	if ((sdp->pageprot == 0) && (dhp != NULL) && dhp_is_devmem(dhp)) {
1991 		pfn_t pfnum;
1992 		uint_t hat_flags;
1993 
1994 		if (dhp->dh_flags & DEVMAP_MAPPING_INVALID) {
1995 			rw_exit(&sdp->lock);
1996 			return (FC_NOMAP);
1997 		}
1998 
1999 		if (type == F_SOFTLOCK) {
2000 			mutex_enter(&freemem_lock);
2001 			sdp->softlockcnt += btopr(len);
2002 			mutex_exit(&freemem_lock);
2003 		}
2004 
2005 		hat_flags = ((type == F_SOFTLOCK) ? HAT_LOAD_LOCK : HAT_LOAD);
2006 		pfnum = dhp->dh_pfn + btop((uintptr_t)(addr - dhp->dh_uvaddr));
2007 		ASSERT(!pf_is_memory(pfnum));
2008 
2009 		hat_devload(hat, addr, len, pfnum, sdp->prot | dhp->dh_hat_attr,
2010 		    hat_flags | sdp->hat_flags);
2011 		rw_exit(&sdp->lock);
2012 		return (0);
2013 	}
2014 
2015 	/* Handle cases where we have to loop through fault handling per-page */
2016 
2017 	if (sdp->vpage == NULL)
2018 		vpage = NULL;
2019 	else
2020 		vpage = &sdp->vpage[seg_page(seg, addr)];
2021 
2022 	/* loop over the address range handling each fault */
2023 	for (a = addr; a < addr + len; a += PAGESIZE) {
2024 		if (err = segdev_faultpage(hat, seg, a, vpage, type, rw, dhp)) {
2025 			break;
2026 		}
2027 		if (vpage != NULL)
2028 			vpage++;
2029 	}
2030 	rw_exit(&sdp->lock);
2031 	if (err && (type == F_SOFTLOCK)) { /* error handling for F_SOFTLOCK */
2032 		size_t done = (size_t)(a - addr); /* pages fault successfully */
2033 		if (done > 0) {
2034 			/* use softunlock for those pages */
2035 			segdev_softunlock(hat, seg, addr, done, S_OTHER);
2036 		}
2037 		if (kpmem_cookie != NULL) {
2038 			/* release kpmem lock for rest of pages */
2039 			ASSERT(len >= done);
2040 			release_kpmem_lock(kpmem_cookie, btopr(len - done));
2041 		}
2042 	} else if ((kpmem_cookie != NULL) && (type != F_SOFTLOCK)) {
2043 		/* for non-SOFTLOCK cases, release kpmem */
2044 		release_kpmem_lock(kpmem_cookie, btopr(len));
2045 	}
2046 	return (err);
2047 }
2048 
2049 /*
2050  * Asynchronous page fault.  We simply do nothing since this
2051  * entry point is not supposed to load up the translation.
2052  */
2053 /*ARGSUSED*/
2054 static faultcode_t
2055 segdev_faulta(struct seg *seg, caddr_t addr)
2056 {
2057 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_FAULTA,
2058 	    "segdev_faulta: seg=%p addr=%p", (void *)seg, (void *)addr);
2059 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2060 
2061 	return (0);
2062 }
2063 
2064 static int
2065 segdev_setprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
2066 {
2067 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2068 	register devmap_handle_t *dhp;
2069 	register struct vpage *vp, *evp;
2070 	devmap_handle_t *dhp_head = (devmap_handle_t *)sdp->devmap_data;
2071 	ulong_t off;
2072 	size_t mlen, sz;
2073 
2074 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_SETPROT,
2075 	    "segdev_setprot:start seg=%p addr=%p len=%lx prot=%x",
2076 	    (void *)seg, (void *)addr, len, prot);
2077 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2078 
2079 	if ((sz = sdp->softlockcnt) > 0 && dhp_head != NULL) {
2080 		/*
2081 		 * Fail the setprot if pages are SOFTLOCKed through this
2082 		 * mapping.
2083 		 * Softlockcnt is protected from change by the as read lock.
2084 		 */
2085 		TRACE_1(TR_FAC_DEVMAP, TR_DEVMAP_SETPROT_CK1,
2086 		    "segdev_setprot:error softlockcnt=%lx", sz);
2087 		DEBUGF(1, (CE_CONT, "segdev_setprot: softlockcnt %ld\n", sz));
2088 		return (EAGAIN);
2089 	}
2090 
2091 	if (dhp_head != NULL) {
2092 		if ((dhp = devmap_find_handle(dhp_head, addr)) == NULL)
2093 			return (EINVAL);
2094 
2095 		/*
2096 		 * check if violate maxprot.
2097 		 */
2098 		off = (ulong_t)(addr - dhp->dh_uvaddr);
2099 		mlen  = len;
2100 		while (dhp) {
2101 			if ((dhp->dh_maxprot & prot) != prot)
2102 				return (EACCES);	/* violated maxprot */
2103 
2104 			if (mlen > (dhp->dh_len - off)) {
2105 				mlen -= dhp->dh_len - off;
2106 				dhp = dhp->dh_next;
2107 				off = 0;
2108 			} else
2109 				break;
2110 		}
2111 	} else {
2112 		if ((sdp->maxprot & prot) != prot)
2113 			return (EACCES);
2114 	}
2115 
2116 	rw_enter(&sdp->lock, RW_WRITER);
2117 	if (addr == seg->s_base && len == seg->s_size && sdp->pageprot == 0) {
2118 		if (sdp->prot == prot) {
2119 			rw_exit(&sdp->lock);
2120 			return (0);			/* all done */
2121 		}
2122 		sdp->prot = (uchar_t)prot;
2123 	} else {
2124 		sdp->pageprot = 1;
2125 		if (sdp->vpage == NULL) {
2126 			/*
2127 			 * First time through setting per page permissions,
2128 			 * initialize all the vpage structures to prot
2129 			 */
2130 			sdp->vpage = kmem_zalloc(vpgtob(seg_pages(seg)),
2131 			    KM_SLEEP);
2132 			evp = &sdp->vpage[seg_pages(seg)];
2133 			for (vp = sdp->vpage; vp < evp; vp++)
2134 				VPP_SETPROT(vp, sdp->prot);
2135 		}
2136 		/*
2137 		 * Now go change the needed vpages protections.
2138 		 */
2139 		evp = &sdp->vpage[seg_page(seg, addr + len)];
2140 		for (vp = &sdp->vpage[seg_page(seg, addr)]; vp < evp; vp++)
2141 			VPP_SETPROT(vp, prot);
2142 	}
2143 	rw_exit(&sdp->lock);
2144 
2145 	if (dhp_head != NULL) {
2146 		devmap_handle_t *tdhp;
2147 		/*
2148 		 * If large page size was used in hat_devload(),
2149 		 * the same page size must be used in hat_unload().
2150 		 */
2151 		dhp = tdhp = devmap_find_handle(dhp_head, addr);
2152 		while (tdhp != NULL) {
2153 			if (tdhp->dh_flags & DEVMAP_FLAG_LARGE) {
2154 				break;
2155 			}
2156 			tdhp = tdhp->dh_next;
2157 		}
2158 		if (tdhp) {
2159 			size_t slen = len;
2160 			size_t mlen;
2161 			size_t soff;
2162 
2163 			soff = (ulong_t)(addr - dhp->dh_uvaddr);
2164 			while (slen != 0) {
2165 				mlen = MIN(slen, (dhp->dh_len - soff));
2166 				hat_unload(seg->s_as->a_hat, dhp->dh_uvaddr,
2167 				    dhp->dh_len, HAT_UNLOAD);
2168 				dhp = dhp->dh_next;
2169 				ASSERT(slen >= mlen);
2170 				slen -= mlen;
2171 				soff = 0;
2172 			}
2173 			return (0);
2174 		}
2175 	}
2176 
2177 	if ((prot & ~PROT_USER) == PROT_NONE) {
2178 		hat_unload(seg->s_as->a_hat, addr, len, HAT_UNLOAD);
2179 	} else {
2180 		/*
2181 		 * RFE: the segment should keep track of all attributes
2182 		 * allowing us to remove the deprecated hat_chgprot
2183 		 * and use hat_chgattr.
2184 		 */
2185 		hat_chgprot(seg->s_as->a_hat, addr, len, prot);
2186 	}
2187 
2188 	return (0);
2189 }
2190 
2191 static int
2192 segdev_checkprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
2193 {
2194 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2195 	struct vpage *vp, *evp;
2196 
2197 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_CHECKPROT,
2198 	    "segdev_checkprot:start seg=%p addr=%p len=%lx prot=%x",
2199 	    (void *)seg, (void *)addr, len, prot);
2200 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2201 
2202 	/*
2203 	 * If segment protection can be used, simply check against them
2204 	 */
2205 	rw_enter(&sdp->lock, RW_READER);
2206 	if (sdp->pageprot == 0) {
2207 		register int err;
2208 
2209 		err = ((sdp->prot & prot) != prot) ? EACCES : 0;
2210 		rw_exit(&sdp->lock);
2211 		return (err);
2212 	}
2213 
2214 	/*
2215 	 * Have to check down to the vpage level
2216 	 */
2217 	evp = &sdp->vpage[seg_page(seg, addr + len)];
2218 	for (vp = &sdp->vpage[seg_page(seg, addr)]; vp < evp; vp++) {
2219 		if ((VPP_PROT(vp) & prot) != prot) {
2220 			rw_exit(&sdp->lock);
2221 			return (EACCES);
2222 		}
2223 	}
2224 	rw_exit(&sdp->lock);
2225 	return (0);
2226 }
2227 
2228 static int
2229 segdev_getprot(struct seg *seg, caddr_t addr, size_t len, uint_t *protv)
2230 {
2231 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2232 	size_t pgno;
2233 
2234 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_GETPROT,
2235 	    "segdev_getprot:start seg=%p addr=%p len=%lx protv=%p",
2236 	    (void *)seg, (void *)addr, len, (void *)protv);
2237 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2238 
2239 	pgno = seg_page(seg, addr + len) - seg_page(seg, addr) + 1;
2240 	if (pgno != 0) {
2241 		rw_enter(&sdp->lock, RW_READER);
2242 		if (sdp->pageprot == 0) {
2243 			do {
2244 				protv[--pgno] = sdp->prot;
2245 			} while (pgno != 0);
2246 		} else {
2247 			size_t pgoff = seg_page(seg, addr);
2248 
2249 			do {
2250 				pgno--;
2251 				protv[pgno] =
2252 				    VPP_PROT(&sdp->vpage[pgno + pgoff]);
2253 			} while (pgno != 0);
2254 		}
2255 		rw_exit(&sdp->lock);
2256 	}
2257 	return (0);
2258 }
2259 
2260 static u_offset_t
2261 segdev_getoffset(register struct seg *seg, caddr_t addr)
2262 {
2263 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2264 
2265 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_GETOFFSET,
2266 	    "segdev_getoffset:start seg=%p addr=%p", (void *)seg, (void *)addr);
2267 
2268 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2269 
2270 	return ((u_offset_t)sdp->offset + (addr - seg->s_base));
2271 }
2272 
2273 /*ARGSUSED*/
2274 static int
2275 segdev_gettype(register struct seg *seg, caddr_t addr)
2276 {
2277 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2278 
2279 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_GETTYPE,
2280 	    "segdev_gettype:start seg=%p addr=%p", (void *)seg, (void *)addr);
2281 
2282 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2283 
2284 	return (sdp->type);
2285 }
2286 
2287 
2288 /*ARGSUSED*/
2289 static int
2290 segdev_getvp(register struct seg *seg, caddr_t addr, struct vnode **vpp)
2291 {
2292 	register struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
2293 
2294 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_GETVP,
2295 	    "segdev_getvp:start seg=%p addr=%p", (void *)seg, (void *)addr);
2296 
2297 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2298 
2299 	/*
2300 	 * Note that this vp is the common_vp of the device, where the
2301 	 * pages are hung ..
2302 	 */
2303 	*vpp = VTOCVP(sdp->vp);
2304 
2305 	return (0);
2306 }
2307 
2308 static void
2309 segdev_badop(void)
2310 {
2311 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SEGDEV_BADOP,
2312 	    "segdev_badop:start");
2313 	panic("segdev_badop");
2314 	/*NOTREACHED*/
2315 }
2316 
2317 /*
2318  * segdev pages are not in the cache, and thus can't really be controlled.
2319  * Hence, syncs are simply always successful.
2320  */
2321 /*ARGSUSED*/
2322 static int
2323 segdev_sync(struct seg *seg, caddr_t addr, size_t len, int attr, uint_t flags)
2324 {
2325 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SYNC, "segdev_sync:start");
2326 
2327 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2328 
2329 	return (0);
2330 }
2331 
2332 /*
2333  * segdev pages are always "in core".
2334  */
2335 /*ARGSUSED*/
2336 static size_t
2337 segdev_incore(struct seg *seg, caddr_t addr, size_t len, char *vec)
2338 {
2339 	size_t v = 0;
2340 
2341 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_INCORE, "segdev_incore:start");
2342 
2343 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2344 
2345 	for (len = (len + PAGEOFFSET) & PAGEMASK; len; len -= PAGESIZE,
2346 	    v += PAGESIZE)
2347 		*vec++ = 1;
2348 	return (v);
2349 }
2350 
2351 /*
2352  * segdev pages are not in the cache, and thus can't really be controlled.
2353  * Hence, locks are simply always successful.
2354  */
2355 /*ARGSUSED*/
2356 static int
2357 segdev_lockop(struct seg *seg, caddr_t addr,
2358     size_t len, int attr, int op, ulong_t *lockmap, size_t pos)
2359 {
2360 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_LOCKOP, "segdev_lockop:start");
2361 
2362 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2363 
2364 	return (0);
2365 }
2366 
2367 /*
2368  * segdev pages are not in the cache, and thus can't really be controlled.
2369  * Hence, advise is simply always successful.
2370  */
2371 /*ARGSUSED*/
2372 static int
2373 segdev_advise(struct seg *seg, caddr_t addr, size_t len, uint_t behav)
2374 {
2375 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_ADVISE, "segdev_advise:start");
2376 
2377 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2378 
2379 	return (0);
2380 }
2381 
2382 /*
2383  * segdev pages are not dumped, so we just return
2384  */
2385 /*ARGSUSED*/
2386 static void
2387 segdev_dump(struct seg *seg)
2388 {}
2389 
2390 /*
2391  * ddi_segmap_setup:	Used by drivers who wish specify mapping attributes
2392  *			for a segment.	Called from a drivers segmap(9E)
2393  *			routine.
2394  */
2395 /*ARGSUSED*/
2396 int
2397 ddi_segmap_setup(dev_t dev, off_t offset, struct as *as, caddr_t *addrp,
2398     off_t len, uint_t prot, uint_t maxprot, uint_t flags, cred_t *cred,
2399     ddi_device_acc_attr_t *accattrp, uint_t rnumber)
2400 {
2401 	struct segdev_crargs dev_a;
2402 	int (*mapfunc)(dev_t dev, off_t off, int prot);
2403 	uint_t hat_attr;
2404 	pfn_t pfn;
2405 	int	error, i;
2406 
2407 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SEGMAP_SETUP,
2408 	    "ddi_segmap_setup:start");
2409 
2410 	if ((mapfunc = devopsp[getmajor(dev)]->devo_cb_ops->cb_mmap) == nodev)
2411 		return (ENODEV);
2412 
2413 	/*
2414 	 * Character devices that support the d_mmap
2415 	 * interface can only be mmap'ed shared.
2416 	 */
2417 	if ((flags & MAP_TYPE) != MAP_SHARED)
2418 		return (EINVAL);
2419 
2420 	/*
2421 	 * Check that this region is indeed mappable on this platform.
2422 	 * Use the mapping function.
2423 	 */
2424 	if (ddi_device_mapping_check(dev, accattrp, rnumber, &hat_attr) == -1)
2425 		return (ENXIO);
2426 
2427 	/*
2428 	 * Check to ensure that the entire range is
2429 	 * legal and we are not trying to map in
2430 	 * more than the device will let us.
2431 	 */
2432 	for (i = 0; i < len; i += PAGESIZE) {
2433 		if (i == 0) {
2434 			/*
2435 			 * Save the pfn at offset here. This pfn will be
2436 			 * used later to get user address.
2437 			 */
2438 			if ((pfn = (pfn_t)cdev_mmap(mapfunc, dev, offset,
2439 			    maxprot)) == PFN_INVALID)
2440 				return (ENXIO);
2441 		} else {
2442 			if (cdev_mmap(mapfunc, dev, offset + i, maxprot) ==
2443 			    PFN_INVALID)
2444 				return (ENXIO);
2445 		}
2446 	}
2447 
2448 	as_rangelock(as);
2449 	/* Pick an address w/o worrying about any vac alignment constraints. */
2450 	error = choose_addr(as, addrp, len, ptob(pfn), ADDR_NOVACALIGN, flags);
2451 	if (error != 0) {
2452 		as_rangeunlock(as);
2453 		return (error);
2454 	}
2455 
2456 	dev_a.mapfunc = mapfunc;
2457 	dev_a.dev = dev;
2458 	dev_a.offset = (offset_t)offset;
2459 	dev_a.type = flags & MAP_TYPE;
2460 	dev_a.prot = (uchar_t)prot;
2461 	dev_a.maxprot = (uchar_t)maxprot;
2462 	dev_a.hat_attr = hat_attr;
2463 	dev_a.hat_flags = 0;
2464 	dev_a.devmap_data = NULL;
2465 
2466 	error = as_map(as, *addrp, len, segdev_create, &dev_a);
2467 	as_rangeunlock(as);
2468 	return (error);
2469 
2470 }
2471 
2472 /*ARGSUSED*/
2473 static int
2474 segdev_pagelock(struct seg *seg, caddr_t addr, size_t len,
2475     struct page ***ppp, enum lock_type type, enum seg_rw rw)
2476 {
2477 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_PAGELOCK,
2478 	    "segdev_pagelock:start");
2479 	return (ENOTSUP);
2480 }
2481 
2482 /*ARGSUSED*/
2483 static int
2484 segdev_setpagesize(struct seg *seg, caddr_t addr, size_t len,
2485     uint_t szc)
2486 {
2487 	return (ENOTSUP);
2488 }
2489 
2490 /*
2491  * devmap_device: Used by devmap framework to establish mapping
2492  *                called by devmap_seup(9F) during map setup time.
2493  */
2494 /*ARGSUSED*/
2495 static int
2496 devmap_device(devmap_handle_t *dhp, struct as *as, caddr_t *addr,
2497     offset_t off, size_t len, uint_t flags)
2498 {
2499 	devmap_handle_t *rdhp, *maxdhp;
2500 	struct segdev_crargs dev_a;
2501 	int	err;
2502 	uint_t maxprot = PROT_ALL;
2503 	offset_t offset = 0;
2504 	pfn_t pfn;
2505 	struct devmap_pmem_cookie *pcp;
2506 
2507 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_DEVICE,
2508 	    "devmap_device:start dhp=%p addr=%p off=%llx, len=%lx",
2509 	    (void *)dhp, (void *)addr, off, len);
2510 
2511 	DEBUGF(2, (CE_CONT, "devmap_device: dhp %p addr %p off %llx len %lx\n",
2512 	    (void *)dhp, (void *)addr, off, len));
2513 
2514 	as_rangelock(as);
2515 	if ((flags & MAP_FIXED) == 0) {
2516 		offset_t aligned_off;
2517 
2518 		rdhp = maxdhp = dhp;
2519 		while (rdhp != NULL) {
2520 			maxdhp = (maxdhp->dh_len > rdhp->dh_len) ?
2521 			    maxdhp : rdhp;
2522 			rdhp = rdhp->dh_next;
2523 			maxprot |= dhp->dh_maxprot;
2524 		}
2525 		offset = maxdhp->dh_uoff - dhp->dh_uoff;
2526 
2527 		/*
2528 		 * Use the dhp that has the
2529 		 * largest len to get user address.
2530 		 */
2531 		/*
2532 		 * If MAPPING_INVALID, cannot use dh_pfn/dh_cvaddr,
2533 		 * use 0 which is as good as any other.
2534 		 */
2535 		if (maxdhp->dh_flags & DEVMAP_MAPPING_INVALID) {
2536 			aligned_off = (offset_t)0;
2537 		} else if (dhp_is_devmem(maxdhp)) {
2538 			aligned_off = (offset_t)ptob(maxdhp->dh_pfn) - offset;
2539 		} else if (dhp_is_pmem(maxdhp)) {
2540 			pcp = (struct devmap_pmem_cookie *)maxdhp->dh_pcookie;
2541 			pfn = page_pptonum(
2542 			    pcp->dp_pparray[btop(maxdhp->dh_roff)]);
2543 			aligned_off = (offset_t)ptob(pfn) - offset;
2544 		} else {
2545 			aligned_off = (offset_t)(uintptr_t)maxdhp->dh_cvaddr -
2546 			    offset;
2547 		}
2548 
2549 		/*
2550 		 * Pick an address aligned to dh_cookie.
2551 		 * for kernel memory/user memory, cookie is cvaddr.
2552 		 * for device memory, cookie is physical address.
2553 		 */
2554 		map_addr(addr, len, aligned_off, 1, flags);
2555 		if (*addr == NULL) {
2556 			as_rangeunlock(as);
2557 			return (ENOMEM);
2558 		}
2559 	} else {
2560 		/*
2561 		 * User-specified address; blow away any previous mappings.
2562 		 */
2563 		(void) as_unmap(as, *addr, len);
2564 	}
2565 
2566 	dev_a.mapfunc = NULL;
2567 	dev_a.dev = dhp->dh_dev;
2568 	dev_a.type = flags & MAP_TYPE;
2569 	dev_a.offset = off;
2570 	/*
2571 	 * sdp->maxprot has the least restrict protection of all dhps.
2572 	 */
2573 	dev_a.maxprot = maxprot;
2574 	dev_a.prot = dhp->dh_prot;
2575 	/*
2576 	 * devmap uses dhp->dh_hat_attr for hat.
2577 	 */
2578 	dev_a.hat_flags = 0;
2579 	dev_a.hat_attr = 0;
2580 	dev_a.devmap_data = (void *)dhp;
2581 
2582 	err = as_map(as, *addr, len, segdev_create, &dev_a);
2583 	as_rangeunlock(as);
2584 	return (err);
2585 }
2586 
2587 int
2588 devmap_do_ctxmgt(devmap_cookie_t dhc, void *pvtp, offset_t off, size_t len,
2589     uint_t type, uint_t rw, int (*ctxmgt)(devmap_cookie_t, void *, offset_t,
2590     size_t, uint_t, uint_t))
2591 {
2592 	register devmap_handle_t *dhp = (devmap_handle_t *)dhc;
2593 	struct devmap_ctx *devctx;
2594 	int do_timeout = 0;
2595 	int ret;
2596 
2597 #ifdef lint
2598 	pvtp = pvtp;
2599 #endif
2600 
2601 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_DO_CTXMGT,
2602 	    "devmap_do_ctxmgt:start dhp=%p off=%llx, len=%lx",
2603 	    (void *)dhp, off, len);
2604 	DEBUGF(7, (CE_CONT, "devmap_do_ctxmgt: dhp %p off %llx len %lx\n",
2605 	    (void *)dhp, off, len));
2606 
2607 	if (ctxmgt == NULL)
2608 		return (FC_HWERR);
2609 
2610 	devctx = dhp->dh_ctx;
2611 
2612 	/*
2613 	 * If we are on an MP system with more than one cpu running
2614 	 * and if a thread on some CPU already has the context, wait
2615 	 * for it to finish if there is a hysteresis timeout.
2616 	 *
2617 	 * We call cv_wait() instead of cv_wait_sig() because
2618 	 * it does not matter much if it returned due to a signal
2619 	 * or due to a cv_signal() or cv_broadcast().  In either event
2620 	 * we need to complete the mapping otherwise the processes
2621 	 * will die with a SEGV.
2622 	 */
2623 	if ((dhp->dh_timeout_length > 0) && (ncpus > 1)) {
2624 		TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_DO_CTXMGT_CK1,
2625 		    "devmap_do_ctxmgt:doing hysteresis, devctl %p dhp %p",
2626 		    devctx, dhp);
2627 		do_timeout = 1;
2628 		mutex_enter(&devctx->lock);
2629 		while (devctx->oncpu)
2630 			cv_wait(&devctx->cv, &devctx->lock);
2631 		devctx->oncpu = 1;
2632 		mutex_exit(&devctx->lock);
2633 	}
2634 
2635 	/*
2636 	 * Call the contextmgt callback so that the driver can handle
2637 	 * the fault.
2638 	 */
2639 	ret = (*ctxmgt)(dhp, dhp->dh_pvtp, off, len, type, rw);
2640 
2641 	/*
2642 	 * If devmap_access() returned -1, then there was a hardware
2643 	 * error so we need to convert the return value to something
2644 	 * that trap() will understand.  Otherwise, the return value
2645 	 * is already a fault code generated by devmap_unload()
2646 	 * or devmap_load().
2647 	 */
2648 	if (ret) {
2649 		TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_DO_CTXMGT_CK2,
2650 		    "devmap_do_ctxmgt: ret=%x dhp=%p devctx=%p",
2651 		    ret, dhp, devctx);
2652 		DEBUGF(1, (CE_CONT, "devmap_do_ctxmgt: ret %x dhp %p\n",
2653 		    ret, (void *)dhp));
2654 		if (devctx->oncpu) {
2655 			mutex_enter(&devctx->lock);
2656 			devctx->oncpu = 0;
2657 			cv_signal(&devctx->cv);
2658 			mutex_exit(&devctx->lock);
2659 		}
2660 		return (FC_HWERR);
2661 	}
2662 
2663 	/*
2664 	 * Setup the timeout if we need to
2665 	 */
2666 	if (do_timeout) {
2667 		mutex_enter(&devctx->lock);
2668 		if (dhp->dh_timeout_length > 0) {
2669 			TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_DO_CTXMGT_CK3,
2670 			    "devmap_do_ctxmgt:timeout set");
2671 			devctx->timeout = timeout(devmap_ctxto,
2672 			    devctx, dhp->dh_timeout_length);
2673 		} else {
2674 			/*
2675 			 * We don't want to wait so set oncpu to
2676 			 * 0 and wake up anyone waiting.
2677 			 */
2678 			TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_DO_CTXMGT_CK4,
2679 			    "devmap_do_ctxmgt:timeout not set");
2680 			devctx->oncpu = 0;
2681 			cv_signal(&devctx->cv);
2682 		}
2683 		mutex_exit(&devctx->lock);
2684 	}
2685 
2686 	return (DDI_SUCCESS);
2687 }
2688 
2689 /*
2690  *                                       end of mapping
2691  *                    poff   fault_offset         |
2692  *            base     |        |                 |
2693  *              |      |        |                 |
2694  *              V      V        V                 V
2695  *  +-----------+---------------+-------+---------+-------+
2696  *              ^               ^       ^         ^
2697  *              |<--- offset--->|<-len->|         |
2698  *              |<--- dh_len(size of mapping) --->|
2699  *                     |<--  pg -->|
2700  *                              -->|rlen|<--
2701  */
2702 static ulong_t
2703 devmap_roundup(devmap_handle_t *dhp, ulong_t offset, size_t len,
2704     ulong_t *opfn, ulong_t *pagesize)
2705 {
2706 	register int level;
2707 	ulong_t pg;
2708 	ulong_t poff;
2709 	ulong_t base;
2710 	caddr_t uvaddr;
2711 	long rlen;
2712 
2713 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_ROUNDUP,
2714 	    "devmap_roundup:start dhp=%p off=%lx len=%lx",
2715 	    (void *)dhp, offset, len);
2716 	DEBUGF(2, (CE_CONT, "devmap_roundup: dhp %p off %lx len %lx\n",
2717 	    (void *)dhp, offset, len));
2718 
2719 	/*
2720 	 * get the max. pagesize that is aligned within the range
2721 	 * <dh_pfn, dh_pfn+offset>.
2722 	 *
2723 	 * The calculations below use physical address to ddetermine
2724 	 * the page size to use. The same calculations can use the
2725 	 * virtual address to determine the page size.
2726 	 */
2727 	base = (ulong_t)ptob(dhp->dh_pfn);
2728 	for (level = dhp->dh_mmulevel; level >= 0; level--) {
2729 		pg = page_get_pagesize(level);
2730 		poff = ((base + offset) & ~(pg - 1));
2731 		uvaddr = dhp->dh_uvaddr + (poff - base);
2732 		if ((poff >= base) &&
2733 		    ((poff + pg) <= (base + dhp->dh_len)) &&
2734 		    VA_PA_ALIGNED((uintptr_t)uvaddr, poff, pg))
2735 			break;
2736 	}
2737 
2738 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_ROUNDUP_CK1,
2739 	    "devmap_roundup: base=%lx poff=%lx dhp=%p",
2740 	    base, poff, dhp);
2741 	DEBUGF(2, (CE_CONT, "devmap_roundup: base %lx poff %lx pfn %lx\n",
2742 	    base, poff, dhp->dh_pfn));
2743 
2744 	ASSERT(VA_PA_ALIGNED((uintptr_t)uvaddr, poff, pg));
2745 	ASSERT(level >= 0);
2746 
2747 	*pagesize = pg;
2748 	*opfn = dhp->dh_pfn + btop(poff - base);
2749 
2750 	rlen = len + offset - (poff - base + pg);
2751 
2752 	ASSERT(rlen < (long)len);
2753 
2754 	TRACE_5(TR_FAC_DEVMAP, TR_DEVMAP_ROUNDUP_CK2,
2755 	    "devmap_roundup:ret dhp=%p level=%x rlen=%lx psiz=%p opfn=%p",
2756 	    (void *)dhp, level, rlen, pagesize, opfn);
2757 	DEBUGF(1, (CE_CONT, "devmap_roundup: dhp %p "
2758 	    "level %x rlen %lx psize %lx opfn %lx\n",
2759 	    (void *)dhp, level, rlen, *pagesize, *opfn));
2760 
2761 	return ((ulong_t)((rlen > 0) ? rlen : 0));
2762 }
2763 
2764 /*
2765  * find the dhp that contains addr.
2766  */
2767 static devmap_handle_t *
2768 devmap_find_handle(devmap_handle_t *dhp_head, caddr_t addr)
2769 {
2770 	devmap_handle_t *dhp;
2771 
2772 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_FIND_HANDLE,
2773 	    "devmap_find_handle:start");
2774 
2775 	dhp = dhp_head;
2776 	while (dhp) {
2777 		if (addr >= dhp->dh_uvaddr &&
2778 		    addr < (dhp->dh_uvaddr + dhp->dh_len))
2779 			return (dhp);
2780 		dhp = dhp->dh_next;
2781 	}
2782 
2783 	return ((devmap_handle_t *)NULL);
2784 }
2785 
2786 /*
2787  * devmap_unload:
2788  *			Marks a segdev segment or pages if offset->offset+len
2789  *			is not the entire segment as intercept and unloads the
2790  *			pages in the range offset -> offset+len.
2791  */
2792 int
2793 devmap_unload(devmap_cookie_t dhc, offset_t offset, size_t len)
2794 {
2795 	register devmap_handle_t *dhp = (devmap_handle_t *)dhc;
2796 	caddr_t	addr;
2797 	ulong_t	size;
2798 	ssize_t	soff;
2799 
2800 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_UNLOAD,
2801 	    "devmap_unload:start dhp=%p offset=%llx len=%lx",
2802 	    (void *)dhp, offset, len);
2803 	DEBUGF(7, (CE_CONT, "devmap_unload: dhp %p offset %llx len %lx\n",
2804 	    (void *)dhp, offset, len));
2805 
2806 	soff = (ssize_t)(offset - dhp->dh_uoff);
2807 	soff = round_down_p2(soff, PAGESIZE);
2808 	if (soff < 0 || soff >= dhp->dh_len)
2809 		return (FC_MAKE_ERR(EINVAL));
2810 
2811 	/*
2812 	 * Address and size must be page aligned.  Len is set to the
2813 	 * number of bytes in the number of pages that are required to
2814 	 * support len.  Offset is set to the byte offset of the first byte
2815 	 * of the page that contains offset.
2816 	 */
2817 	len = round_up_p2(len, PAGESIZE);
2818 
2819 	/*
2820 	 * If len is == 0, then calculate the size by getting
2821 	 * the number of bytes from offset to the end of the segment.
2822 	 */
2823 	if (len == 0)
2824 		size = dhp->dh_len - soff;
2825 	else {
2826 		size = len;
2827 		if ((soff + size) > dhp->dh_len)
2828 			return (FC_MAKE_ERR(EINVAL));
2829 	}
2830 
2831 	/*
2832 	 * The address is offset bytes from the base address of
2833 	 * the dhp.
2834 	 */
2835 	addr = (caddr_t)(soff + dhp->dh_uvaddr);
2836 
2837 	/*
2838 	 * If large page size was used in hat_devload(),
2839 	 * the same page size must be used in hat_unload().
2840 	 */
2841 	if (dhp->dh_flags & DEVMAP_FLAG_LARGE) {
2842 		hat_unload(dhp->dh_seg->s_as->a_hat, dhp->dh_uvaddr,
2843 		    dhp->dh_len, HAT_UNLOAD|HAT_UNLOAD_OTHER);
2844 	} else {
2845 		hat_unload(dhp->dh_seg->s_as->a_hat,  addr, size,
2846 		    HAT_UNLOAD|HAT_UNLOAD_OTHER);
2847 	}
2848 
2849 	return (0);
2850 }
2851 
2852 /*
2853  * calculates the optimal page size that will be used for hat_devload().
2854  */
2855 static void
2856 devmap_get_large_pgsize(devmap_handle_t *dhp, size_t len, caddr_t addr,
2857     size_t *llen, caddr_t *laddr)
2858 {
2859 	ulong_t off;
2860 	ulong_t pfn;
2861 	ulong_t pgsize;
2862 	uint_t first = 1;
2863 
2864 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_GET_LARGE_PGSIZE,
2865 	    "devmap_get_large_pgsize:start");
2866 
2867 	/*
2868 	 * RFE - Code only supports large page mappings for devmem
2869 	 * This code could be changed in future if we want to support
2870 	 * large page mappings for kernel exported memory.
2871 	 */
2872 	ASSERT(dhp_is_devmem(dhp));
2873 	ASSERT(!(dhp->dh_flags & DEVMAP_MAPPING_INVALID));
2874 
2875 	*llen = 0;
2876 	off = (ulong_t)(addr - dhp->dh_uvaddr);
2877 	while ((long)len > 0) {
2878 		/*
2879 		 * get the optimal pfn to minimize address translations.
2880 		 * devmap_roundup() returns residue bytes for next round
2881 		 * calculations.
2882 		 */
2883 		len = devmap_roundup(dhp, off, len, &pfn, &pgsize);
2884 
2885 		if (first) {
2886 			*laddr = dhp->dh_uvaddr + ptob(pfn - dhp->dh_pfn);
2887 			first = 0;
2888 		}
2889 
2890 		*llen += pgsize;
2891 		off = ptob(pfn - dhp->dh_pfn) + pgsize;
2892 	}
2893 	/* Large page mapping len/addr cover more range than original fault */
2894 	ASSERT(*llen >= len && *laddr <= addr);
2895 	ASSERT((*laddr + *llen) >= (addr + len));
2896 }
2897 
2898 /*
2899  * Initialize the devmap_softlock structure.
2900  */
2901 static struct devmap_softlock *
2902 devmap_softlock_init(dev_t dev, ulong_t id)
2903 {
2904 	struct devmap_softlock *slock;
2905 	struct devmap_softlock *tmp;
2906 
2907 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SOFTLOCK_INIT,
2908 	    "devmap_softlock_init:start");
2909 
2910 	tmp = kmem_zalloc(sizeof (struct devmap_softlock), KM_SLEEP);
2911 	mutex_enter(&devmap_slock);
2912 
2913 	for (slock = devmap_slist; slock != NULL; slock = slock->next)
2914 		if ((slock->dev == dev) && (slock->id == id))
2915 			break;
2916 
2917 	if (slock == NULL) {
2918 		slock = tmp;
2919 		slock->dev = dev;
2920 		slock->id = id;
2921 		mutex_init(&slock->lock, NULL, MUTEX_DEFAULT, NULL);
2922 		cv_init(&slock->cv, NULL, CV_DEFAULT, NULL);
2923 		slock->next = devmap_slist;
2924 		devmap_slist = slock;
2925 	} else
2926 		kmem_free(tmp, sizeof (struct devmap_softlock));
2927 
2928 	mutex_enter(&slock->lock);
2929 	slock->refcnt++;
2930 	mutex_exit(&slock->lock);
2931 	mutex_exit(&devmap_slock);
2932 
2933 	return (slock);
2934 }
2935 
2936 /*
2937  * Wake up processes that sleep on softlocked.
2938  * Free dh_softlock if refcnt is 0.
2939  */
2940 static void
2941 devmap_softlock_rele(devmap_handle_t *dhp)
2942 {
2943 	struct devmap_softlock *slock = dhp->dh_softlock;
2944 	struct devmap_softlock *tmp;
2945 	struct devmap_softlock *parent;
2946 
2947 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SOFTLOCK_RELE,
2948 	    "devmap_softlock_rele:start");
2949 
2950 	mutex_enter(&devmap_slock);
2951 	mutex_enter(&slock->lock);
2952 
2953 	ASSERT(slock->refcnt > 0);
2954 
2955 	slock->refcnt--;
2956 
2957 	/*
2958 	 * If no one is using the device, free up the slock data.
2959 	 */
2960 	if (slock->refcnt == 0) {
2961 		slock->softlocked = 0;
2962 		cv_signal(&slock->cv);
2963 
2964 		if (devmap_slist == slock)
2965 			devmap_slist = slock->next;
2966 		else {
2967 			parent = devmap_slist;
2968 			for (tmp = devmap_slist->next; tmp != NULL;
2969 			    tmp = tmp->next) {
2970 				if (tmp == slock) {
2971 					parent->next = tmp->next;
2972 					break;
2973 				}
2974 				parent = tmp;
2975 			}
2976 		}
2977 		mutex_exit(&slock->lock);
2978 		mutex_destroy(&slock->lock);
2979 		cv_destroy(&slock->cv);
2980 		kmem_free(slock, sizeof (struct devmap_softlock));
2981 	} else
2982 		mutex_exit(&slock->lock);
2983 
2984 	mutex_exit(&devmap_slock);
2985 }
2986 
2987 /*
2988  * Wake up processes that sleep on dh_ctx->locked.
2989  * Free dh_ctx if refcnt is 0.
2990  */
2991 static void
2992 devmap_ctx_rele(devmap_handle_t *dhp)
2993 {
2994 	struct devmap_ctx *devctx = dhp->dh_ctx;
2995 	struct devmap_ctx *tmp;
2996 	struct devmap_ctx *parent;
2997 	timeout_id_t tid;
2998 
2999 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_CTX_RELE,
3000 	    "devmap_ctx_rele:start");
3001 
3002 	mutex_enter(&devmapctx_lock);
3003 	mutex_enter(&devctx->lock);
3004 
3005 	ASSERT(devctx->refcnt > 0);
3006 
3007 	devctx->refcnt--;
3008 
3009 	/*
3010 	 * If no one is using the device, free up the devctx data.
3011 	 */
3012 	if (devctx->refcnt == 0) {
3013 		/*
3014 		 * Untimeout any threads using this mapping as they are about
3015 		 * to go away.
3016 		 */
3017 		if (devctx->timeout != 0) {
3018 			TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_CTX_RELE_CK1,
3019 			    "devmap_ctx_rele:untimeout ctx->timeout");
3020 
3021 			tid = devctx->timeout;
3022 			mutex_exit(&devctx->lock);
3023 			(void) untimeout(tid);
3024 			mutex_enter(&devctx->lock);
3025 		}
3026 
3027 		devctx->oncpu = 0;
3028 		cv_signal(&devctx->cv);
3029 
3030 		if (devmapctx_list == devctx)
3031 			devmapctx_list = devctx->next;
3032 		else {
3033 			parent = devmapctx_list;
3034 			for (tmp = devmapctx_list->next; tmp != NULL;
3035 			    tmp = tmp->next) {
3036 				if (tmp == devctx) {
3037 					parent->next = tmp->next;
3038 					break;
3039 				}
3040 				parent = tmp;
3041 			}
3042 		}
3043 		mutex_exit(&devctx->lock);
3044 		mutex_destroy(&devctx->lock);
3045 		cv_destroy(&devctx->cv);
3046 		kmem_free(devctx, sizeof (struct devmap_ctx));
3047 	} else
3048 		mutex_exit(&devctx->lock);
3049 
3050 	mutex_exit(&devmapctx_lock);
3051 }
3052 
3053 /*
3054  * devmap_load:
3055  *			Marks a segdev segment or pages if offset->offset+len
3056  *			is not the entire segment as nointercept and faults in
3057  *			the pages in the range offset -> offset+len.
3058  */
3059 int
3060 devmap_load(devmap_cookie_t dhc, offset_t offset, size_t len, uint_t type,
3061     uint_t rw)
3062 {
3063 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3064 	struct as *asp = dhp->dh_seg->s_as;
3065 	caddr_t	addr;
3066 	ulong_t	size;
3067 	ssize_t	soff;	/* offset from the beginning of the segment */
3068 	int rc;
3069 
3070 	TRACE_3(TR_FAC_DEVMAP, TR_DEVMAP_LOAD,
3071 	    "devmap_load:start dhp=%p offset=%llx len=%lx",
3072 	    (void *)dhp, offset, len);
3073 
3074 	DEBUGF(7, (CE_CONT, "devmap_load: dhp %p offset %llx len %lx\n",
3075 	    (void *)dhp, offset, len));
3076 
3077 	/*
3078 	 *	Hat layer only supports devload to process' context for which
3079 	 *	the as lock is held. Verify here and return error if drivers
3080 	 *	inadvertently call devmap_load on a wrong devmap handle.
3081 	 */
3082 	if ((asp != &kas) && !AS_LOCK_HELD(asp, &asp->a_lock))
3083 		return (FC_MAKE_ERR(EINVAL));
3084 
3085 	soff = (ssize_t)(offset - dhp->dh_uoff);
3086 	soff = round_down_p2(soff, PAGESIZE);
3087 	if (soff < 0 || soff >= dhp->dh_len)
3088 		return (FC_MAKE_ERR(EINVAL));
3089 
3090 	/*
3091 	 * Address and size must be page aligned.  Len is set to the
3092 	 * number of bytes in the number of pages that are required to
3093 	 * support len.  Offset is set to the byte offset of the first byte
3094 	 * of the page that contains offset.
3095 	 */
3096 	len = round_up_p2(len, PAGESIZE);
3097 
3098 	/*
3099 	 * If len == 0, then calculate the size by getting
3100 	 * the number of bytes from offset to the end of the segment.
3101 	 */
3102 	if (len == 0)
3103 		size = dhp->dh_len - soff;
3104 	else {
3105 		size = len;
3106 		if ((soff + size) > dhp->dh_len)
3107 			return (FC_MAKE_ERR(EINVAL));
3108 	}
3109 
3110 	/*
3111 	 * The address is offset bytes from the base address of
3112 	 * the segment.
3113 	 */
3114 	addr = (caddr_t)(soff + dhp->dh_uvaddr);
3115 
3116 	HOLD_DHP_LOCK(dhp);
3117 	rc = segdev_faultpages(asp->a_hat,
3118 	    dhp->dh_seg, addr, size, type, rw, dhp);
3119 	RELE_DHP_LOCK(dhp);
3120 	return (rc);
3121 }
3122 
3123 int
3124 devmap_setup(dev_t dev, offset_t off, struct as *as, caddr_t *addrp,
3125     size_t len, uint_t prot, uint_t maxprot, uint_t flags, struct cred *cred)
3126 {
3127 	register devmap_handle_t *dhp;
3128 	int (*devmap)(dev_t, devmap_cookie_t, offset_t, size_t,
3129 	    size_t *, uint_t);
3130 	int (*mmap)(dev_t, off_t, int);
3131 	struct devmap_callback_ctl *callbackops;
3132 	devmap_handle_t *dhp_head = NULL;
3133 	devmap_handle_t *dhp_prev = NULL;
3134 	devmap_handle_t *dhp_curr;
3135 	caddr_t addr;
3136 	int map_flag;
3137 	int ret;
3138 	ulong_t total_len;
3139 	size_t map_len;
3140 	size_t resid_len = len;
3141 	offset_t map_off = off;
3142 	struct devmap_softlock *slock = NULL;
3143 
3144 #ifdef lint
3145 	cred = cred;
3146 #endif
3147 
3148 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_SETUP,
3149 	    "devmap_setup:start off=%llx len=%lx", off, len);
3150 	DEBUGF(3, (CE_CONT, "devmap_setup: off %llx len %lx\n",
3151 	    off, len));
3152 
3153 	devmap = devopsp[getmajor(dev)]->devo_cb_ops->cb_devmap;
3154 	mmap = devopsp[getmajor(dev)]->devo_cb_ops->cb_mmap;
3155 
3156 	/*
3157 	 * driver must provide devmap(9E) entry point in cb_ops to use the
3158 	 * devmap framework.
3159 	 */
3160 	if (devmap == NULL || devmap == nulldev || devmap == nodev)
3161 		return (EINVAL);
3162 
3163 	/*
3164 	 * To protect from an inadvertent entry because the devmap entry point
3165 	 * is not NULL, return error if D_DEVMAP bit is not set in cb_flag and
3166 	 * mmap is NULL.
3167 	 */
3168 	map_flag = devopsp[getmajor(dev)]->devo_cb_ops->cb_flag;
3169 	if ((map_flag & D_DEVMAP) == 0 && (mmap == NULL || mmap == nulldev))
3170 		return (EINVAL);
3171 
3172 	/*
3173 	 * devmap allows mmap(2) to map multiple registers.
3174 	 * one devmap_handle is created for each register mapped.
3175 	 */
3176 	for (total_len = 0; total_len < len; total_len += map_len) {
3177 		dhp = kmem_zalloc(sizeof (devmap_handle_t), KM_SLEEP);
3178 
3179 		if (dhp_prev != NULL)
3180 			dhp_prev->dh_next = dhp;
3181 		else
3182 			dhp_head = dhp;
3183 		dhp_prev = dhp;
3184 
3185 		dhp->dh_prot = prot;
3186 		dhp->dh_orig_maxprot = dhp->dh_maxprot = maxprot;
3187 		dhp->dh_dev = dev;
3188 		dhp->dh_timeout_length = CTX_TIMEOUT_VALUE;
3189 		dhp->dh_uoff = map_off;
3190 
3191 		/*
3192 		 * Get mapping specific info from
3193 		 * the driver, such as rnumber, roff, len, callbackops,
3194 		 * accattrp and, if the mapping is for kernel memory,
3195 		 * ddi_umem_cookie.
3196 		 */
3197 		if ((ret = cdev_devmap(dev, dhp, map_off,
3198 		    resid_len, &map_len, get_udatamodel())) != 0) {
3199 			free_devmap_handle(dhp_head);
3200 			return (ENXIO);
3201 		}
3202 
3203 		if (map_len & PAGEOFFSET) {
3204 			free_devmap_handle(dhp_head);
3205 			return (EINVAL);
3206 		}
3207 
3208 		callbackops = &dhp->dh_callbackops;
3209 
3210 		if ((callbackops->devmap_access == NULL) ||
3211 		    (callbackops->devmap_access == nulldev) ||
3212 		    (callbackops->devmap_access == nodev)) {
3213 			/*
3214 			 * Normally devmap does not support MAP_PRIVATE unless
3215 			 * the drivers provide a valid devmap_access routine.
3216 			 */
3217 			if ((flags & MAP_PRIVATE) != 0) {
3218 				free_devmap_handle(dhp_head);
3219 				return (EINVAL);
3220 			}
3221 		} else {
3222 			/*
3223 			 * Initialize dhp_softlock and dh_ctx if the drivers
3224 			 * provide devmap_access.
3225 			 */
3226 			dhp->dh_softlock = devmap_softlock_init(dev,
3227 			    (ulong_t)callbackops->devmap_access);
3228 			dhp->dh_ctx = devmap_ctxinit(dev,
3229 			    (ulong_t)callbackops->devmap_access);
3230 
3231 			/*
3232 			 * segdev_fault can only work when all
3233 			 * dh_softlock in a multi-dhp mapping
3234 			 * are same. see comments in segdev_fault
3235 			 * This code keeps track of the first
3236 			 * dh_softlock allocated in slock and
3237 			 * compares all later allocations and if
3238 			 * not similar, returns an error.
3239 			 */
3240 			if (slock == NULL)
3241 				slock = dhp->dh_softlock;
3242 			if (slock != dhp->dh_softlock) {
3243 				free_devmap_handle(dhp_head);
3244 				return (ENOTSUP);
3245 			}
3246 		}
3247 
3248 		map_off += map_len;
3249 		resid_len -= map_len;
3250 	}
3251 
3252 	/*
3253 	 * get the user virtual address and establish the mapping between
3254 	 * uvaddr and device physical address.
3255 	 */
3256 	if ((ret = devmap_device(dhp_head, as, addrp, off, len, flags))
3257 	    != 0) {
3258 		/*
3259 		 * free devmap handles if error during the mapping.
3260 		 */
3261 		free_devmap_handle(dhp_head);
3262 
3263 		return (ret);
3264 	}
3265 
3266 	/*
3267 	 * call the driver's devmap_map callback to do more after the mapping,
3268 	 * such as to allocate driver private data for context management.
3269 	 */
3270 	dhp = dhp_head;
3271 	map_off = off;
3272 	addr = *addrp;
3273 	while (dhp != NULL) {
3274 		callbackops = &dhp->dh_callbackops;
3275 		dhp->dh_uvaddr = addr;
3276 		dhp_curr = dhp;
3277 		if (callbackops->devmap_map != NULL) {
3278 			ret = (*callbackops->devmap_map)((devmap_cookie_t)dhp,
3279 			    dev, flags, map_off,
3280 			    dhp->dh_len, &dhp->dh_pvtp);
3281 			if (ret != 0) {
3282 				struct segdev_data *sdp;
3283 
3284 				/*
3285 				 * call driver's devmap_unmap entry point
3286 				 * to free driver resources.
3287 				 */
3288 				dhp = dhp_head;
3289 				map_off = off;
3290 				while (dhp != dhp_curr) {
3291 					callbackops = &dhp->dh_callbackops;
3292 					if (callbackops->devmap_unmap != NULL) {
3293 						(*callbackops->devmap_unmap)(
3294 						    dhp, dhp->dh_pvtp,
3295 						    map_off, dhp->dh_len,
3296 						    NULL, NULL, NULL, NULL);
3297 					}
3298 					map_off += dhp->dh_len;
3299 					dhp = dhp->dh_next;
3300 				}
3301 				sdp = dhp_head->dh_seg->s_data;
3302 				sdp->devmap_data = NULL;
3303 				free_devmap_handle(dhp_head);
3304 				return (ENXIO);
3305 			}
3306 		}
3307 		map_off += dhp->dh_len;
3308 		addr += dhp->dh_len;
3309 		dhp = dhp->dh_next;
3310 	}
3311 
3312 	return (0);
3313 }
3314 
3315 int
3316 ddi_devmap_segmap(dev_t dev, off_t off, ddi_as_handle_t as, caddr_t *addrp,
3317     off_t len, uint_t prot, uint_t maxprot, uint_t flags, struct cred *cred)
3318 {
3319 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_SEGMAP,
3320 	    "devmap_segmap:start");
3321 	return (devmap_setup(dev, (offset_t)off, (struct as *)as, addrp,
3322 	    (size_t)len, prot, maxprot, flags, cred));
3323 }
3324 
3325 /*
3326  * Called from devmap_devmem_setup/remap to see if can use large pages for
3327  * this device mapping.
3328  * Also calculate the max. page size for this mapping.
3329  * this page size will be used in fault routine for
3330  * optimal page size calculations.
3331  */
3332 static void
3333 devmap_devmem_large_page_setup(devmap_handle_t *dhp)
3334 {
3335 	ASSERT(dhp_is_devmem(dhp));
3336 	dhp->dh_mmulevel = 0;
3337 
3338 	/*
3339 	 * use large page size only if:
3340 	 *  1. device memory.
3341 	 *  2. mmu supports multiple page sizes,
3342 	 *  3. Driver did not disallow it
3343 	 *  4. dhp length is at least as big as the large pagesize
3344 	 *  5. the uvaddr and pfn are large pagesize aligned
3345 	 */
3346 	if (page_num_pagesizes() > 1 &&
3347 	    !(dhp->dh_flags & (DEVMAP_USE_PAGESIZE | DEVMAP_MAPPING_INVALID))) {
3348 		ulong_t base;
3349 		int level;
3350 
3351 		base = (ulong_t)ptob(dhp->dh_pfn);
3352 		for (level = 1; level < page_num_pagesizes(); level++) {
3353 			size_t pgsize = page_get_pagesize(level);
3354 			if ((dhp->dh_len < pgsize) ||
3355 			    (!VA_PA_PGSIZE_ALIGNED((uintptr_t)dhp->dh_uvaddr,
3356 			    base, pgsize))) {
3357 				break;
3358 			}
3359 		}
3360 		dhp->dh_mmulevel = level - 1;
3361 	}
3362 	if (dhp->dh_mmulevel > 0) {
3363 		dhp->dh_flags |= DEVMAP_FLAG_LARGE;
3364 	} else {
3365 		dhp->dh_flags &= ~DEVMAP_FLAG_LARGE;
3366 	}
3367 }
3368 
3369 /*
3370  * Called by driver devmap routine to pass device specific info to
3371  * the framework.    used for device memory mapping only.
3372  */
3373 int
3374 devmap_devmem_setup(devmap_cookie_t dhc, dev_info_t *dip,
3375     struct devmap_callback_ctl *callbackops, uint_t rnumber, offset_t roff,
3376     size_t len, uint_t maxprot, uint_t flags, ddi_device_acc_attr_t *accattrp)
3377 {
3378 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3379 	ddi_acc_handle_t handle;
3380 	ddi_map_req_t mr;
3381 	ddi_acc_hdl_t *hp;
3382 	int err;
3383 
3384 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_DEVMEM_SETUP,
3385 	    "devmap_devmem_setup:start dhp=%p offset=%llx rnum=%d len=%lx",
3386 	    (void *)dhp, roff, rnumber, (uint_t)len);
3387 	DEBUGF(2, (CE_CONT, "devmap_devmem_setup: dhp %p offset %llx "
3388 	    "rnum %d len %lx\n", (void *)dhp, roff, rnumber, len));
3389 
3390 	/*
3391 	 * First to check if this function has been called for this dhp.
3392 	 */
3393 	if (dhp->dh_flags & DEVMAP_SETUP_DONE)
3394 		return (DDI_FAILURE);
3395 
3396 	if ((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) != dhp->dh_prot)
3397 		return (DDI_FAILURE);
3398 
3399 	if (flags & DEVMAP_MAPPING_INVALID) {
3400 		/*
3401 		 * Don't go up the tree to get pfn if the driver specifies
3402 		 * DEVMAP_MAPPING_INVALID in flags.
3403 		 *
3404 		 * If DEVMAP_MAPPING_INVALID is specified, we have to grant
3405 		 * remap permission.
3406 		 */
3407 		if (!(flags & DEVMAP_ALLOW_REMAP)) {
3408 			return (DDI_FAILURE);
3409 		}
3410 		dhp->dh_pfn = PFN_INVALID;
3411 	} else {
3412 		handle = impl_acc_hdl_alloc(KM_SLEEP, NULL);
3413 		if (handle == NULL)
3414 			return (DDI_FAILURE);
3415 
3416 		hp = impl_acc_hdl_get(handle);
3417 		hp->ah_vers = VERS_ACCHDL;
3418 		hp->ah_dip = dip;
3419 		hp->ah_rnumber = rnumber;
3420 		hp->ah_offset = roff;
3421 		hp->ah_len = len;
3422 		if (accattrp != NULL)
3423 			hp->ah_acc = *accattrp;
3424 
3425 		mr.map_op = DDI_MO_MAP_LOCKED;
3426 		mr.map_type = DDI_MT_RNUMBER;
3427 		mr.map_obj.rnumber = rnumber;
3428 		mr.map_prot = maxprot & dhp->dh_orig_maxprot;
3429 		mr.map_flags = DDI_MF_DEVICE_MAPPING;
3430 		mr.map_handlep = hp;
3431 		mr.map_vers = DDI_MAP_VERSION;
3432 
3433 		/*
3434 		 * up the device tree to get pfn.
3435 		 * The rootnex_map_regspec() routine in nexus drivers has been
3436 		 * modified to return pfn if map_flags is DDI_MF_DEVICE_MAPPING.
3437 		 */
3438 		err = ddi_map(dip, &mr, roff, len, (caddr_t *)&dhp->dh_pfn);
3439 		dhp->dh_hat_attr = hp->ah_hat_flags;
3440 		impl_acc_hdl_free(handle);
3441 
3442 		if (err)
3443 			return (DDI_FAILURE);
3444 	}
3445 	/* Should not be using devmem setup for memory pages */
3446 	ASSERT(!pf_is_memory(dhp->dh_pfn));
3447 
3448 	/* Only some of the flags bits are settable by the driver */
3449 	dhp->dh_flags |= (flags & DEVMAP_SETUP_FLAGS);
3450 	dhp->dh_len = ptob(btopr(len));
3451 
3452 	dhp->dh_cookie = DEVMAP_DEVMEM_COOKIE;
3453 	dhp->dh_roff = ptob(btop(roff));
3454 
3455 	/* setup the dh_mmulevel and DEVMAP_FLAG_LARGE */
3456 	devmap_devmem_large_page_setup(dhp);
3457 	dhp->dh_maxprot = maxprot & dhp->dh_orig_maxprot;
3458 	ASSERT((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) == dhp->dh_prot);
3459 
3460 
3461 	if (callbackops != NULL) {
3462 		bcopy(callbackops, &dhp->dh_callbackops,
3463 		    sizeof (struct devmap_callback_ctl));
3464 	}
3465 
3466 	/*
3467 	 * Initialize dh_lock if we want to do remap.
3468 	 */
3469 	if (dhp->dh_flags & DEVMAP_ALLOW_REMAP) {
3470 		mutex_init(&dhp->dh_lock, NULL, MUTEX_DEFAULT, NULL);
3471 		dhp->dh_flags |= DEVMAP_LOCK_INITED;
3472 	}
3473 
3474 	dhp->dh_flags |= DEVMAP_SETUP_DONE;
3475 
3476 	return (DDI_SUCCESS);
3477 }
3478 
3479 int
3480 devmap_devmem_remap(devmap_cookie_t dhc, dev_info_t *dip,
3481     uint_t rnumber, offset_t roff, size_t len, uint_t maxprot,
3482     uint_t flags, ddi_device_acc_attr_t *accattrp)
3483 {
3484 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3485 	ddi_acc_handle_t handle;
3486 	ddi_map_req_t mr;
3487 	ddi_acc_hdl_t *hp;
3488 	pfn_t	pfn;
3489 	uint_t	hat_flags;
3490 	int	err;
3491 
3492 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_DEVMEM_REMAP,
3493 	    "devmap_devmem_setup:start dhp=%p offset=%llx rnum=%d len=%lx",
3494 	    (void *)dhp, roff, rnumber, (uint_t)len);
3495 	DEBUGF(2, (CE_CONT, "devmap_devmem_remap: dhp %p offset %llx "
3496 	    "rnum %d len %lx\n", (void *)dhp, roff, rnumber, len));
3497 
3498 	/*
3499 	 * Return failure if setup has not been done or no remap permission
3500 	 * has been granted during the setup.
3501 	 */
3502 	if ((dhp->dh_flags & DEVMAP_SETUP_DONE) == 0 ||
3503 	    (dhp->dh_flags & DEVMAP_ALLOW_REMAP) == 0)
3504 		return (DDI_FAILURE);
3505 
3506 	/* Only DEVMAP_MAPPING_INVALID flag supported for remap */
3507 	if ((flags != 0) && (flags != DEVMAP_MAPPING_INVALID))
3508 		return (DDI_FAILURE);
3509 
3510 	if ((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) != dhp->dh_prot)
3511 		return (DDI_FAILURE);
3512 
3513 	if (!(flags & DEVMAP_MAPPING_INVALID)) {
3514 		handle = impl_acc_hdl_alloc(KM_SLEEP, NULL);
3515 		if (handle == NULL)
3516 			return (DDI_FAILURE);
3517 	}
3518 
3519 	HOLD_DHP_LOCK(dhp);
3520 
3521 	/*
3522 	 * Unload the old mapping, so next fault will setup the new mappings
3523 	 * Do this while holding the dhp lock so other faults dont reestablish
3524 	 * the mappings
3525 	 */
3526 	hat_unload(dhp->dh_seg->s_as->a_hat, dhp->dh_uvaddr,
3527 	    dhp->dh_len, HAT_UNLOAD|HAT_UNLOAD_OTHER);
3528 
3529 	if (flags & DEVMAP_MAPPING_INVALID) {
3530 		dhp->dh_flags |= DEVMAP_MAPPING_INVALID;
3531 		dhp->dh_pfn = PFN_INVALID;
3532 	} else {
3533 		/* clear any prior DEVMAP_MAPPING_INVALID flag */
3534 		dhp->dh_flags &= ~DEVMAP_MAPPING_INVALID;
3535 		hp = impl_acc_hdl_get(handle);
3536 		hp->ah_vers = VERS_ACCHDL;
3537 		hp->ah_dip = dip;
3538 		hp->ah_rnumber = rnumber;
3539 		hp->ah_offset = roff;
3540 		hp->ah_len = len;
3541 		if (accattrp != NULL)
3542 			hp->ah_acc = *accattrp;
3543 
3544 		mr.map_op = DDI_MO_MAP_LOCKED;
3545 		mr.map_type = DDI_MT_RNUMBER;
3546 		mr.map_obj.rnumber = rnumber;
3547 		mr.map_prot = maxprot & dhp->dh_orig_maxprot;
3548 		mr.map_flags = DDI_MF_DEVICE_MAPPING;
3549 		mr.map_handlep = hp;
3550 		mr.map_vers = DDI_MAP_VERSION;
3551 
3552 		/*
3553 		 * up the device tree to get pfn.
3554 		 * The rootnex_map_regspec() routine in nexus drivers has been
3555 		 * modified to return pfn if map_flags is DDI_MF_DEVICE_MAPPING.
3556 		 */
3557 		err = ddi_map(dip, &mr, roff, len, (caddr_t *)&pfn);
3558 		hat_flags = hp->ah_hat_flags;
3559 		impl_acc_hdl_free(handle);
3560 		if (err) {
3561 			RELE_DHP_LOCK(dhp);
3562 			return (DDI_FAILURE);
3563 		}
3564 		/*
3565 		 * Store result of ddi_map first in local variables, as we do
3566 		 * not want to overwrite the existing dhp with wrong data.
3567 		 */
3568 		dhp->dh_pfn = pfn;
3569 		dhp->dh_hat_attr = hat_flags;
3570 	}
3571 
3572 	/* clear the large page size flag */
3573 	dhp->dh_flags &= ~DEVMAP_FLAG_LARGE;
3574 
3575 	dhp->dh_cookie = DEVMAP_DEVMEM_COOKIE;
3576 	dhp->dh_roff = ptob(btop(roff));
3577 
3578 	/* setup the dh_mmulevel and DEVMAP_FLAG_LARGE */
3579 	devmap_devmem_large_page_setup(dhp);
3580 	dhp->dh_maxprot = maxprot & dhp->dh_orig_maxprot;
3581 	ASSERT((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) == dhp->dh_prot);
3582 
3583 	RELE_DHP_LOCK(dhp);
3584 	return (DDI_SUCCESS);
3585 }
3586 
3587 /*
3588  * called by driver devmap routine to pass kernel virtual address  mapping
3589  * info to the framework.    used only for kernel memory
3590  * allocated from ddi_umem_alloc().
3591  */
3592 int
3593 devmap_umem_setup(devmap_cookie_t dhc, dev_info_t *dip,
3594     struct devmap_callback_ctl *callbackops, ddi_umem_cookie_t cookie,
3595     offset_t off, size_t len, uint_t maxprot, uint_t flags,
3596     ddi_device_acc_attr_t *accattrp)
3597 {
3598 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3599 	struct ddi_umem_cookie *cp = (struct ddi_umem_cookie *)cookie;
3600 
3601 #ifdef lint
3602 	dip = dip;
3603 #endif
3604 
3605 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_UMEM_SETUP,
3606 	    "devmap_umem_setup:start dhp=%p offset=%llx cookie=%p len=%lx",
3607 	    (void *)dhp, off, cookie, len);
3608 	DEBUGF(2, (CE_CONT, "devmap_umem_setup: dhp %p offset %llx "
3609 	    "cookie %p len %lx\n", (void *)dhp, off, (void *)cookie, len));
3610 
3611 	if (cookie == NULL)
3612 		return (DDI_FAILURE);
3613 
3614 	/* For UMEM_TRASH, this restriction is not needed */
3615 	if ((off + len) > cp->size)
3616 		return (DDI_FAILURE);
3617 
3618 	/* check if the cache attributes are supported */
3619 	if (i_ddi_check_cache_attr(flags) == B_FALSE)
3620 		return (DDI_FAILURE);
3621 
3622 	/*
3623 	 * First to check if this function has been called for this dhp.
3624 	 */
3625 	if (dhp->dh_flags & DEVMAP_SETUP_DONE)
3626 		return (DDI_FAILURE);
3627 
3628 	if ((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) != dhp->dh_prot)
3629 		return (DDI_FAILURE);
3630 
3631 	if (flags & DEVMAP_MAPPING_INVALID) {
3632 		/*
3633 		 * If DEVMAP_MAPPING_INVALID is specified, we have to grant
3634 		 * remap permission.
3635 		 */
3636 		if (!(flags & DEVMAP_ALLOW_REMAP)) {
3637 			return (DDI_FAILURE);
3638 		}
3639 	} else {
3640 		dhp->dh_cookie = cookie;
3641 		dhp->dh_roff = ptob(btop(off));
3642 		dhp->dh_cvaddr = cp->cvaddr + dhp->dh_roff;
3643 		/* set HAT cache attributes */
3644 		i_ddi_cacheattr_to_hatacc(flags, &dhp->dh_hat_attr);
3645 		/* set HAT endianess attributes */
3646 		i_ddi_devacc_to_hatacc(accattrp, &dhp->dh_hat_attr);
3647 	}
3648 
3649 	/*
3650 	 * The default is _not_ to pass HAT_LOAD_NOCONSIST to hat_devload();
3651 	 * we pass HAT_LOAD_NOCONSIST _only_ in cases where hat tries to
3652 	 * create consistent mappings but our intention was to create
3653 	 * non-consistent mappings.
3654 	 *
3655 	 * DEVMEM: hat figures it out it's DEVMEM and creates non-consistent
3656 	 * mappings.
3657 	 *
3658 	 * kernel exported memory: hat figures it out it's memory and always
3659 	 * creates consistent mappings.
3660 	 *
3661 	 * /dev/mem: non-consistent mappings. See comments in common/io/mem.c
3662 	 *
3663 	 * /dev/kmem: consistent mappings are created unless they are
3664 	 * MAP_FIXED. We _explicitly_ tell hat to create non-consistent
3665 	 * mappings by passing HAT_LOAD_NOCONSIST in case of MAP_FIXED
3666 	 * mappings of /dev/kmem. See common/io/mem.c
3667 	 */
3668 
3669 	/* Only some of the flags bits are settable by the driver */
3670 	dhp->dh_flags |= (flags & DEVMAP_SETUP_FLAGS);
3671 
3672 	dhp->dh_len = ptob(btopr(len));
3673 	dhp->dh_maxprot = maxprot & dhp->dh_orig_maxprot;
3674 	ASSERT((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) == dhp->dh_prot);
3675 
3676 	if (callbackops != NULL) {
3677 		bcopy(callbackops, &dhp->dh_callbackops,
3678 		    sizeof (struct devmap_callback_ctl));
3679 	}
3680 	/*
3681 	 * Initialize dh_lock if we want to do remap.
3682 	 */
3683 	if (dhp->dh_flags & DEVMAP_ALLOW_REMAP) {
3684 		mutex_init(&dhp->dh_lock, NULL, MUTEX_DEFAULT, NULL);
3685 		dhp->dh_flags |= DEVMAP_LOCK_INITED;
3686 	}
3687 
3688 	dhp->dh_flags |= DEVMAP_SETUP_DONE;
3689 
3690 	return (DDI_SUCCESS);
3691 }
3692 
3693 int
3694 devmap_umem_remap(devmap_cookie_t dhc, dev_info_t *dip,
3695     ddi_umem_cookie_t cookie, offset_t off, size_t len, uint_t maxprot,
3696     uint_t flags, ddi_device_acc_attr_t *accattrp)
3697 {
3698 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3699 	struct ddi_umem_cookie *cp = (struct ddi_umem_cookie *)cookie;
3700 
3701 	TRACE_4(TR_FAC_DEVMAP, TR_DEVMAP_UMEM_REMAP,
3702 	    "devmap_umem_remap:start dhp=%p offset=%llx cookie=%p len=%lx",
3703 	    (void *)dhp, off, cookie, len);
3704 	DEBUGF(2, (CE_CONT, "devmap_umem_remap: dhp %p offset %llx "
3705 	    "cookie %p len %lx\n", (void *)dhp, off, (void *)cookie, len));
3706 
3707 #ifdef lint
3708 	dip = dip;
3709 	accattrp = accattrp;
3710 #endif
3711 	/*
3712 	 * Reture failure if setup has not been done or no remap permission
3713 	 * has been granted during the setup.
3714 	 */
3715 	if ((dhp->dh_flags & DEVMAP_SETUP_DONE) == 0 ||
3716 	    (dhp->dh_flags & DEVMAP_ALLOW_REMAP) == 0)
3717 		return (DDI_FAILURE);
3718 
3719 	/* No flags supported for remap yet */
3720 	if (flags != 0)
3721 		return (DDI_FAILURE);
3722 
3723 	/* check if the cache attributes are supported */
3724 	if (i_ddi_check_cache_attr(flags) == B_FALSE)
3725 		return (DDI_FAILURE);
3726 
3727 	if ((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) != dhp->dh_prot)
3728 		return (DDI_FAILURE);
3729 
3730 	/* For UMEM_TRASH, this restriction is not needed */
3731 	if ((off + len) > cp->size)
3732 		return (DDI_FAILURE);
3733 
3734 	HOLD_DHP_LOCK(dhp);
3735 	/*
3736 	 * Unload the old mapping, so next fault will setup the new mappings
3737 	 * Do this while holding the dhp lock so other faults dont reestablish
3738 	 * the mappings
3739 	 */
3740 	hat_unload(dhp->dh_seg->s_as->a_hat, dhp->dh_uvaddr,
3741 	    dhp->dh_len, HAT_UNLOAD|HAT_UNLOAD_OTHER);
3742 
3743 	dhp->dh_cookie = cookie;
3744 	dhp->dh_roff = ptob(btop(off));
3745 	dhp->dh_cvaddr = cp->cvaddr + dhp->dh_roff;
3746 	/* set HAT cache attributes */
3747 	i_ddi_cacheattr_to_hatacc(flags, &dhp->dh_hat_attr);
3748 	/* set HAT endianess attributes */
3749 	i_ddi_devacc_to_hatacc(accattrp, &dhp->dh_hat_attr);
3750 
3751 	/* clear the large page size flag */
3752 	dhp->dh_flags &= ~DEVMAP_FLAG_LARGE;
3753 
3754 	dhp->dh_maxprot = maxprot & dhp->dh_orig_maxprot;
3755 	ASSERT((dhp->dh_prot & dhp->dh_orig_maxprot & maxprot) == dhp->dh_prot);
3756 	RELE_DHP_LOCK(dhp);
3757 	return (DDI_SUCCESS);
3758 }
3759 
3760 /*
3761  * to set timeout value for the driver's context management callback, e.g.
3762  * devmap_access().
3763  */
3764 void
3765 devmap_set_ctx_timeout(devmap_cookie_t dhc, clock_t ticks)
3766 {
3767 	devmap_handle_t *dhp = (devmap_handle_t *)dhc;
3768 
3769 	TRACE_2(TR_FAC_DEVMAP, TR_DEVMAP_SET_CTX_TIMEOUT,
3770 	    "devmap_set_ctx_timeout:start dhp=%p ticks=%x",
3771 	    (void *)dhp, ticks);
3772 	dhp->dh_timeout_length = ticks;
3773 }
3774 
3775 int
3776 devmap_default_access(devmap_cookie_t dhp, void *pvtp, offset_t off,
3777     size_t len, uint_t type, uint_t rw)
3778 {
3779 #ifdef lint
3780 	pvtp = pvtp;
3781 #endif
3782 
3783 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_DEFAULT_ACCESS,
3784 	    "devmap_default_access:start");
3785 	return (devmap_load(dhp, off, len, type, rw));
3786 }
3787 
3788 /*
3789  * segkmem_alloc() wrapper to allocate memory which is both
3790  * non-relocatable (for DR) and sharelocked, since the rest
3791  * of this segment driver requires it.
3792  */
3793 static void *
3794 devmap_alloc_pages(vmem_t *vmp, size_t size, int vmflag)
3795 {
3796 	ASSERT(vmp != NULL);
3797 	ASSERT(kvseg.s_base != NULL);
3798 	vmflag |= (VM_NORELOC | SEGKMEM_SHARELOCKED);
3799 	return (segkmem_alloc(vmp, size, vmflag));
3800 }
3801 
3802 /*
3803  * This is where things are a bit incestuous with seg_kmem: unlike
3804  * seg_kp, seg_kmem does not keep its pages long-term sharelocked, so
3805  * we need to do a bit of a dance around that to prevent duplication of
3806  * code until we decide to bite the bullet and implement a new kernel
3807  * segment for driver-allocated memory that is exported to user space.
3808  */
3809 static void
3810 devmap_free_pages(vmem_t *vmp, void *inaddr, size_t size)
3811 {
3812 	page_t *pp;
3813 	caddr_t addr = inaddr;
3814 	caddr_t eaddr;
3815 	pgcnt_t npages = btopr(size);
3816 
3817 	ASSERT(vmp != NULL);
3818 	ASSERT(kvseg.s_base != NULL);
3819 	ASSERT(((uintptr_t)addr & PAGEOFFSET) == 0);
3820 
3821 	hat_unload(kas.a_hat, addr, size, HAT_UNLOAD_UNLOCK);
3822 
3823 	for (eaddr = addr + size; addr < eaddr; addr += PAGESIZE) {
3824 		/*
3825 		 * Use page_find() instead of page_lookup() to find the page
3826 		 * since we know that it is hashed and has a shared lock.
3827 		 */
3828 		pp = page_find(&kvp, (u_offset_t)(uintptr_t)addr);
3829 
3830 		if (pp == NULL)
3831 			panic("devmap_free_pages: page not found");
3832 		if (!page_tryupgrade(pp)) {
3833 			page_unlock(pp);
3834 			pp = page_lookup(&kvp, (u_offset_t)(uintptr_t)addr,
3835 			    SE_EXCL);
3836 			if (pp == NULL)
3837 				panic("devmap_free_pages: page already freed");
3838 		}
3839 		/* Clear p_lckcnt so page_destroy() doesn't update availrmem */
3840 		pp->p_lckcnt = 0;
3841 		page_destroy(pp, 0);
3842 	}
3843 	page_unresv(npages);
3844 
3845 	if (vmp != NULL)
3846 		vmem_free(vmp, inaddr, size);
3847 }
3848 
3849 /*
3850  * devmap_umem_alloc_np() replaces kmem_zalloc() as the method for
3851  * allocating non-pageable kmem in response to a ddi_umem_alloc()
3852  * default request. For now we allocate our own pages and we keep
3853  * them long-term sharelocked, since: A) the fault routines expect the
3854  * memory to already be locked; B) pageable umem is already long-term
3855  * locked; C) it's a lot of work to make it otherwise, particularly
3856  * since the nexus layer expects the pages to never fault. An RFE is to
3857  * not keep the pages long-term locked, but instead to be able to
3858  * take faults on them and simply look them up in kvp in case we
3859  * fault on them. Even then, we must take care not to let pageout
3860  * steal them from us since the data must remain resident; if we
3861  * do this we must come up with some way to pin the pages to prevent
3862  * faults while a driver is doing DMA to/from them.
3863  */
3864 static void *
3865 devmap_umem_alloc_np(size_t size, size_t flags)
3866 {
3867 	void *buf;
3868 	int vmflags = (flags & DDI_UMEM_NOSLEEP)? VM_NOSLEEP : VM_SLEEP;
3869 
3870 	buf = vmem_alloc(umem_np_arena, size, vmflags);
3871 	if (buf != NULL)
3872 		bzero(buf, size);
3873 	return (buf);
3874 }
3875 
3876 static void
3877 devmap_umem_free_np(void *addr, size_t size)
3878 {
3879 	vmem_free(umem_np_arena, addr, size);
3880 }
3881 
3882 /*
3883  * allocate page aligned kernel memory for exporting to user land.
3884  * The devmap framework will use the cookie allocated by ddi_umem_alloc()
3885  * to find a user virtual address that is in same color as the address
3886  * allocated here.
3887  */
3888 void *
3889 ddi_umem_alloc(size_t size, int flags, ddi_umem_cookie_t *cookie)
3890 {
3891 	register size_t len = ptob(btopr(size));
3892 	void *buf = NULL;
3893 	struct ddi_umem_cookie *cp;
3894 	int iflags = 0;
3895 
3896 	*cookie = NULL;
3897 
3898 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_UMEM_ALLOC,
3899 	    "devmap_umem_alloc:start");
3900 	if (len == 0)
3901 		return ((void *)NULL);
3902 
3903 	/*
3904 	 * allocate cookie
3905 	 */
3906 	if ((cp = kmem_zalloc(sizeof (struct ddi_umem_cookie),
3907 	    flags & DDI_UMEM_NOSLEEP ? KM_NOSLEEP : KM_SLEEP)) == NULL) {
3908 		ASSERT(flags & DDI_UMEM_NOSLEEP);
3909 		return ((void *)NULL);
3910 	}
3911 
3912 	if (flags & DDI_UMEM_PAGEABLE) {
3913 		/* Only one of the flags is allowed */
3914 		ASSERT(!(flags & DDI_UMEM_TRASH));
3915 		/* initialize resource with 0 */
3916 		iflags = KPD_ZERO;
3917 
3918 		/*
3919 		 * to allocate unlocked pageable memory, use segkp_get() to
3920 		 * create a segkp segment.  Since segkp can only service kas,
3921 		 * other segment drivers such as segdev have to do
3922 		 * as_fault(segkp, SOFTLOCK) in its fault routine,
3923 		 */
3924 		if (flags & DDI_UMEM_NOSLEEP)
3925 			iflags |= KPD_NOWAIT;
3926 
3927 		if ((buf = segkp_get(segkp, len, iflags)) == NULL) {
3928 			kmem_free(cp, sizeof (struct ddi_umem_cookie));
3929 			return ((void *)NULL);
3930 		}
3931 		cp->type = KMEM_PAGEABLE;
3932 		mutex_init(&cp->lock, NULL, MUTEX_DEFAULT, NULL);
3933 		cp->locked = 0;
3934 	} else if (flags & DDI_UMEM_TRASH) {
3935 		/* Only one of the flags is allowed */
3936 		ASSERT(!(flags & DDI_UMEM_PAGEABLE));
3937 		cp->type = UMEM_TRASH;
3938 		buf = NULL;
3939 	} else {
3940 		if ((buf = devmap_umem_alloc_np(len, flags)) == NULL) {
3941 			kmem_free(cp, sizeof (struct ddi_umem_cookie));
3942 			return ((void *)NULL);
3943 		}
3944 
3945 		cp->type = KMEM_NON_PAGEABLE;
3946 	}
3947 
3948 	/*
3949 	 * need to save size here.  size will be used when
3950 	 * we do kmem_free.
3951 	 */
3952 	cp->size = len;
3953 	cp->cvaddr = (caddr_t)buf;
3954 
3955 	*cookie =  (void *)cp;
3956 	return (buf);
3957 }
3958 
3959 void
3960 ddi_umem_free(ddi_umem_cookie_t cookie)
3961 {
3962 	struct ddi_umem_cookie *cp;
3963 
3964 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_UMEM_FREE,
3965 	    "devmap_umem_free:start");
3966 
3967 	/*
3968 	 * if cookie is NULL, no effects on the system
3969 	 */
3970 	if (cookie == NULL)
3971 		return;
3972 
3973 	cp = (struct ddi_umem_cookie *)cookie;
3974 
3975 	switch (cp->type) {
3976 	case KMEM_PAGEABLE :
3977 		ASSERT(cp->cvaddr != NULL && cp->size != 0);
3978 		/*
3979 		 * Check if there are still any pending faults on the cookie
3980 		 * while the driver is deleting it,
3981 		 * XXX - could change to an ASSERT but wont catch errant drivers
3982 		 */
3983 		mutex_enter(&cp->lock);
3984 		if (cp->locked) {
3985 			mutex_exit(&cp->lock);
3986 			panic("ddi_umem_free for cookie with pending faults %p",
3987 			    (void *)cp);
3988 			return;
3989 		}
3990 
3991 		segkp_release(segkp, cp->cvaddr);
3992 
3993 		/*
3994 		 * release mutex associated with this cookie.
3995 		 */
3996 		mutex_destroy(&cp->lock);
3997 		break;
3998 	case KMEM_NON_PAGEABLE :
3999 		ASSERT(cp->cvaddr != NULL && cp->size != 0);
4000 		devmap_umem_free_np(cp->cvaddr, cp->size);
4001 		break;
4002 	case UMEM_TRASH :
4003 		break;
4004 	case UMEM_LOCKED :
4005 		/* Callers should use ddi_umem_unlock for this type */
4006 		ddi_umem_unlock(cookie);
4007 		/* Frees the cookie too */
4008 		return;
4009 	default:
4010 		/* panic so we can diagnose the underlying cause */
4011 		panic("ddi_umem_free: illegal cookie type 0x%x\n",
4012 		    cp->type);
4013 	}
4014 
4015 	kmem_free(cookie, sizeof (struct ddi_umem_cookie));
4016 }
4017 
4018 
4019 static int
4020 segdev_getmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
4021 {
4022 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
4023 
4024 	/*
4025 	 * It looks as if it is always mapped shared
4026 	 */
4027 	TRACE_0(TR_FAC_DEVMAP, TR_DEVMAP_GETMEMID,
4028 	    "segdev_getmemid:start");
4029 	memidp->val[0] = (uintptr_t)VTOCVP(sdp->vp);
4030 	memidp->val[1] = sdp->offset + (uintptr_t)(addr - seg->s_base);
4031 	return (0);
4032 }
4033 
4034 /*ARGSUSED*/
4035 static lgrp_mem_policy_info_t *
4036 segdev_getpolicy(struct seg *seg, caddr_t addr)
4037 {
4038 	return (NULL);
4039 }
4040 
4041 /*ARGSUSED*/
4042 static int
4043 segdev_capable(struct seg *seg, segcapability_t capability)
4044 {
4045 	return (0);
4046 }
4047 
4048 /*
4049  * ddi_umem_alloc() non-pageable quantum cache max size.
4050  * This is just a SWAG.
4051  */
4052 #define	DEVMAP_UMEM_QUANTUM	(8*PAGESIZE)
4053 
4054 /*
4055  * Initialize seg_dev from boot. This routine sets up the trash page
4056  * and creates the umem_np_arena used to back non-pageable memory
4057  * requests.
4058  */
4059 void
4060 segdev_init(void)
4061 {
4062 	struct seg kseg;
4063 
4064 	umem_np_arena = vmem_create("umem_np", NULL, 0, PAGESIZE,
4065 	    devmap_alloc_pages, devmap_free_pages, heap_arena,
4066 	    DEVMAP_UMEM_QUANTUM, VM_SLEEP);
4067 
4068 	kseg.s_as = &kas;
4069 	trashpp = page_create_va(&trashvp, 0, PAGESIZE,
4070 	    PG_NORELOC | PG_EXCL | PG_WAIT, &kseg, NULL);
4071 	if (trashpp == NULL)
4072 		panic("segdev_init: failed to create trash page");
4073 	pagezero(trashpp, 0, PAGESIZE);
4074 	page_downgrade(trashpp);
4075 }
4076 
4077 /*
4078  * Invoke platform-dependent support routines so that /proc can have
4079  * the platform code deal with curious hardware.
4080  */
4081 int
4082 segdev_copyfrom(struct seg *seg,
4083     caddr_t uaddr, const void *devaddr, void *kaddr, size_t len)
4084 {
4085 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
4086 	struct snode *sp = VTOS(VTOCVP(sdp->vp));
4087 
4088 	return (e_ddi_copyfromdev(sp->s_dip,
4089 	    (off_t)(uaddr - seg->s_base), devaddr, kaddr, len));
4090 }
4091 
4092 int
4093 segdev_copyto(struct seg *seg,
4094     caddr_t uaddr, const void *kaddr, void *devaddr, size_t len)
4095 {
4096 	struct segdev_data *sdp = (struct segdev_data *)seg->s_data;
4097 	struct snode *sp = VTOS(VTOCVP(sdp->vp));
4098 
4099 	return (e_ddi_copytodev(sp->s_dip,
4100 	    (off_t)(uaddr - seg->s_base), kaddr, devaddr, len));
4101 }
4102