staging: msm/lcdc.c: Convert IS_ERR result to PTR_ERR
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / xen / grant-table.c
blob9ef54ebc1194d74281cd2545d72c6296f26fc313
1 /******************************************************************************
2 * grant_table.c
4 * Granting foreign access to our memory reservation.
6 * Copyright (c) 2005-2006, Christopher Clark
7 * Copyright (c) 2004-2005, K A Fraser
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation; or, when distributed
12 * separately from the Linux kernel or incorporated into other
13 * software packages, subject to the following license:
15 * Permission is hereby granted, free of charge, to any person obtaining a copy
16 * of this source file (the "Software"), to deal in the Software without
17 * restriction, including without limitation the rights to use, copy, modify,
18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
19 * and to permit persons to whom the Software is furnished to do so, subject to
20 * the following conditions:
22 * The above copyright notice and this permission notice shall be included in
23 * all copies or substantial portions of the Software.
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
31 * IN THE SOFTWARE.
34 #include <linux/module.h>
35 #include <linux/sched.h>
36 #include <linux/mm.h>
37 #include <linux/slab.h>
38 #include <linux/vmalloc.h>
39 #include <linux/uaccess.h>
40 #include <linux/io.h>
42 #include <xen/xen.h>
43 #include <xen/interface/xen.h>
44 #include <xen/page.h>
45 #include <xen/grant_table.h>
46 #include <xen/interface/memory.h>
47 #include <asm/xen/hypercall.h>
49 #include <asm/pgtable.h>
50 #include <asm/sync_bitops.h>
53 /* External tools reserve first few grant table entries. */
54 #define NR_RESERVED_ENTRIES 8
55 #define GNTTAB_LIST_END 0xffffffff
56 #define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry))
58 static grant_ref_t **gnttab_list;
59 static unsigned int nr_grant_frames;
60 static unsigned int boot_max_nr_grant_frames;
61 static int gnttab_free_count;
62 static grant_ref_t gnttab_free_head;
63 static DEFINE_SPINLOCK(gnttab_list_lock);
64 unsigned long xen_hvm_resume_frames;
65 EXPORT_SYMBOL_GPL(xen_hvm_resume_frames);
67 static struct grant_entry *shared;
69 static struct gnttab_free_callback *gnttab_free_callback_list;
71 static int gnttab_expand(unsigned int req_entries);
73 #define RPP (PAGE_SIZE / sizeof(grant_ref_t))
75 static inline grant_ref_t *__gnttab_entry(grant_ref_t entry)
77 return &gnttab_list[(entry) / RPP][(entry) % RPP];
79 /* This can be used as an l-value */
80 #define gnttab_entry(entry) (*__gnttab_entry(entry))
82 static int get_free_entries(unsigned count)
84 unsigned long flags;
85 int ref, rc;
86 grant_ref_t head;
88 spin_lock_irqsave(&gnttab_list_lock, flags);
90 if ((gnttab_free_count < count) &&
91 ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
92 spin_unlock_irqrestore(&gnttab_list_lock, flags);
93 return rc;
96 ref = head = gnttab_free_head;
97 gnttab_free_count -= count;
98 while (count-- > 1)
99 head = gnttab_entry(head);
100 gnttab_free_head = gnttab_entry(head);
101 gnttab_entry(head) = GNTTAB_LIST_END;
103 spin_unlock_irqrestore(&gnttab_list_lock, flags);
105 return ref;
108 static void do_free_callbacks(void)
110 struct gnttab_free_callback *callback, *next;
112 callback = gnttab_free_callback_list;
113 gnttab_free_callback_list = NULL;
115 while (callback != NULL) {
116 next = callback->next;
117 if (gnttab_free_count >= callback->count) {
118 callback->next = NULL;
119 callback->fn(callback->arg);
120 } else {
121 callback->next = gnttab_free_callback_list;
122 gnttab_free_callback_list = callback;
124 callback = next;
128 static inline void check_free_callbacks(void)
130 if (unlikely(gnttab_free_callback_list))
131 do_free_callbacks();
134 static void put_free_entry(grant_ref_t ref)
136 unsigned long flags;
137 spin_lock_irqsave(&gnttab_list_lock, flags);
138 gnttab_entry(ref) = gnttab_free_head;
139 gnttab_free_head = ref;
140 gnttab_free_count++;
141 check_free_callbacks();
142 spin_unlock_irqrestore(&gnttab_list_lock, flags);
145 static void update_grant_entry(grant_ref_t ref, domid_t domid,
146 unsigned long frame, unsigned flags)
149 * Introducing a valid entry into the grant table:
150 * 1. Write ent->domid.
151 * 2. Write ent->frame:
152 * GTF_permit_access: Frame to which access is permitted.
153 * GTF_accept_transfer: Pseudo-phys frame slot being filled by new
154 * frame, or zero if none.
155 * 3. Write memory barrier (WMB).
156 * 4. Write ent->flags, inc. valid type.
158 shared[ref].frame = frame;
159 shared[ref].domid = domid;
160 wmb();
161 shared[ref].flags = flags;
165 * Public grant-issuing interface functions
167 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
168 unsigned long frame, int readonly)
170 update_grant_entry(ref, domid, frame,
171 GTF_permit_access | (readonly ? GTF_readonly : 0));
173 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
175 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
176 int readonly)
178 int ref;
180 ref = get_free_entries(1);
181 if (unlikely(ref < 0))
182 return -ENOSPC;
184 gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
186 return ref;
188 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
190 int gnttab_query_foreign_access(grant_ref_t ref)
192 u16 nflags;
194 nflags = shared[ref].flags;
196 return (nflags & (GTF_reading|GTF_writing));
198 EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
200 int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
202 u16 flags, nflags;
204 nflags = shared[ref].flags;
205 do {
206 flags = nflags;
207 if (flags & (GTF_reading|GTF_writing)) {
208 printk(KERN_ALERT "WARNING: g.e. still in use!\n");
209 return 0;
211 } while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) != flags);
213 return 1;
215 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
217 void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
218 unsigned long page)
220 if (gnttab_end_foreign_access_ref(ref, readonly)) {
221 put_free_entry(ref);
222 if (page != 0)
223 free_page(page);
224 } else {
225 /* XXX This needs to be fixed so that the ref and page are
226 placed on a list to be freed up later. */
227 printk(KERN_WARNING
228 "WARNING: leaking g.e. and page still in use!\n");
231 EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
233 int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
235 int ref;
237 ref = get_free_entries(1);
238 if (unlikely(ref < 0))
239 return -ENOSPC;
240 gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
242 return ref;
244 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
246 void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
247 unsigned long pfn)
249 update_grant_entry(ref, domid, pfn, GTF_accept_transfer);
251 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
253 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
255 unsigned long frame;
256 u16 flags;
259 * If a transfer is not even yet started, try to reclaim the grant
260 * reference and return failure (== 0).
262 while (!((flags = shared[ref].flags) & GTF_transfer_committed)) {
263 if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags)
264 return 0;
265 cpu_relax();
268 /* If a transfer is in progress then wait until it is completed. */
269 while (!(flags & GTF_transfer_completed)) {
270 flags = shared[ref].flags;
271 cpu_relax();
274 rmb(); /* Read the frame number /after/ reading completion status. */
275 frame = shared[ref].frame;
276 BUG_ON(frame == 0);
278 return frame;
280 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
282 unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
284 unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
285 put_free_entry(ref);
286 return frame;
288 EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
290 void gnttab_free_grant_reference(grant_ref_t ref)
292 put_free_entry(ref);
294 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
296 void gnttab_free_grant_references(grant_ref_t head)
298 grant_ref_t ref;
299 unsigned long flags;
300 int count = 1;
301 if (head == GNTTAB_LIST_END)
302 return;
303 spin_lock_irqsave(&gnttab_list_lock, flags);
304 ref = head;
305 while (gnttab_entry(ref) != GNTTAB_LIST_END) {
306 ref = gnttab_entry(ref);
307 count++;
309 gnttab_entry(ref) = gnttab_free_head;
310 gnttab_free_head = head;
311 gnttab_free_count += count;
312 check_free_callbacks();
313 spin_unlock_irqrestore(&gnttab_list_lock, flags);
315 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
317 int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
319 int h = get_free_entries(count);
321 if (h < 0)
322 return -ENOSPC;
324 *head = h;
326 return 0;
328 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
330 int gnttab_empty_grant_references(const grant_ref_t *private_head)
332 return (*private_head == GNTTAB_LIST_END);
334 EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
336 int gnttab_claim_grant_reference(grant_ref_t *private_head)
338 grant_ref_t g = *private_head;
339 if (unlikely(g == GNTTAB_LIST_END))
340 return -ENOSPC;
341 *private_head = gnttab_entry(g);
342 return g;
344 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
346 void gnttab_release_grant_reference(grant_ref_t *private_head,
347 grant_ref_t release)
349 gnttab_entry(release) = *private_head;
350 *private_head = release;
352 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
354 void gnttab_request_free_callback(struct gnttab_free_callback *callback,
355 void (*fn)(void *), void *arg, u16 count)
357 unsigned long flags;
358 spin_lock_irqsave(&gnttab_list_lock, flags);
359 if (callback->next)
360 goto out;
361 callback->fn = fn;
362 callback->arg = arg;
363 callback->count = count;
364 callback->next = gnttab_free_callback_list;
365 gnttab_free_callback_list = callback;
366 check_free_callbacks();
367 out:
368 spin_unlock_irqrestore(&gnttab_list_lock, flags);
370 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
372 void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
374 struct gnttab_free_callback **pcb;
375 unsigned long flags;
377 spin_lock_irqsave(&gnttab_list_lock, flags);
378 for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
379 if (*pcb == callback) {
380 *pcb = callback->next;
381 break;
384 spin_unlock_irqrestore(&gnttab_list_lock, flags);
386 EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
388 static int grow_gnttab_list(unsigned int more_frames)
390 unsigned int new_nr_grant_frames, extra_entries, i;
391 unsigned int nr_glist_frames, new_nr_glist_frames;
393 new_nr_grant_frames = nr_grant_frames + more_frames;
394 extra_entries = more_frames * GREFS_PER_GRANT_FRAME;
396 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
397 new_nr_glist_frames =
398 (new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
399 for (i = nr_glist_frames; i < new_nr_glist_frames; i++) {
400 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
401 if (!gnttab_list[i])
402 goto grow_nomem;
406 for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames;
407 i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++)
408 gnttab_entry(i) = i + 1;
410 gnttab_entry(i) = gnttab_free_head;
411 gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames;
412 gnttab_free_count += extra_entries;
414 nr_grant_frames = new_nr_grant_frames;
416 check_free_callbacks();
418 return 0;
420 grow_nomem:
421 for ( ; i >= nr_glist_frames; i--)
422 free_page((unsigned long) gnttab_list[i]);
423 return -ENOMEM;
426 static unsigned int __max_nr_grant_frames(void)
428 struct gnttab_query_size query;
429 int rc;
431 query.dom = DOMID_SELF;
433 rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
434 if ((rc < 0) || (query.status != GNTST_okay))
435 return 4; /* Legacy max supported number of frames */
437 return query.max_nr_frames;
440 unsigned int gnttab_max_grant_frames(void)
442 unsigned int xen_max = __max_nr_grant_frames();
444 if (xen_max > boot_max_nr_grant_frames)
445 return boot_max_nr_grant_frames;
446 return xen_max;
448 EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
450 int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
451 struct page **pages, unsigned int count)
453 int i, ret;
454 pte_t *pte;
455 unsigned long mfn;
457 ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
458 if (ret)
459 return ret;
461 for (i = 0; i < count; i++) {
462 /* m2p override only supported for GNTMAP_contains_pte mappings */
463 if (!(map_ops[i].flags & GNTMAP_contains_pte))
464 continue;
465 pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
466 (map_ops[i].host_addr & ~PAGE_MASK));
467 mfn = pte_mfn(*pte);
468 ret = m2p_add_override(mfn, pages[i]);
469 if (ret)
470 return ret;
473 return ret;
475 EXPORT_SYMBOL_GPL(gnttab_map_refs);
477 int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
478 struct page **pages, unsigned int count)
480 int i, ret;
482 ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
483 if (ret)
484 return ret;
486 for (i = 0; i < count; i++) {
487 ret = m2p_remove_override(pages[i]);
488 if (ret)
489 return ret;
492 return ret;
494 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
496 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
498 struct gnttab_setup_table setup;
499 unsigned long *frames;
500 unsigned int nr_gframes = end_idx + 1;
501 int rc;
503 if (xen_hvm_domain()) {
504 struct xen_add_to_physmap xatp;
505 unsigned int i = end_idx;
506 rc = 0;
508 * Loop backwards, so that the first hypercall has the largest
509 * index, ensuring that the table will grow only once.
511 do {
512 xatp.domid = DOMID_SELF;
513 xatp.idx = i;
514 xatp.space = XENMAPSPACE_grant_table;
515 xatp.gpfn = (xen_hvm_resume_frames >> PAGE_SHIFT) + i;
516 rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
517 if (rc != 0) {
518 printk(KERN_WARNING
519 "grant table add_to_physmap failed, err=%d\n", rc);
520 break;
522 } while (i-- > start_idx);
524 return rc;
527 frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
528 if (!frames)
529 return -ENOMEM;
531 setup.dom = DOMID_SELF;
532 setup.nr_frames = nr_gframes;
533 set_xen_guest_handle(setup.frame_list, frames);
535 rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
536 if (rc == -ENOSYS) {
537 kfree(frames);
538 return -ENOSYS;
541 BUG_ON(rc || setup.status);
543 rc = arch_gnttab_map_shared(frames, nr_gframes, gnttab_max_grant_frames(),
544 &shared);
545 BUG_ON(rc);
547 kfree(frames);
549 return 0;
552 int gnttab_resume(void)
554 unsigned int max_nr_gframes;
556 max_nr_gframes = gnttab_max_grant_frames();
557 if (max_nr_gframes < nr_grant_frames)
558 return -ENOSYS;
560 if (xen_pv_domain())
561 return gnttab_map(0, nr_grant_frames - 1);
563 if (!shared) {
564 shared = ioremap(xen_hvm_resume_frames, PAGE_SIZE * max_nr_gframes);
565 if (shared == NULL) {
566 printk(KERN_WARNING
567 "Failed to ioremap gnttab share frames!");
568 return -ENOMEM;
572 gnttab_map(0, nr_grant_frames - 1);
574 return 0;
577 int gnttab_suspend(void)
579 arch_gnttab_unmap_shared(shared, nr_grant_frames);
580 return 0;
583 static int gnttab_expand(unsigned int req_entries)
585 int rc;
586 unsigned int cur, extra;
588 cur = nr_grant_frames;
589 extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
590 GREFS_PER_GRANT_FRAME);
591 if (cur + extra > gnttab_max_grant_frames())
592 return -ENOSPC;
594 rc = gnttab_map(cur, cur + extra - 1);
595 if (rc == 0)
596 rc = grow_gnttab_list(extra);
598 return rc;
601 int gnttab_init(void)
603 int i;
604 unsigned int max_nr_glist_frames, nr_glist_frames;
605 unsigned int nr_init_grefs;
607 nr_grant_frames = 1;
608 boot_max_nr_grant_frames = __max_nr_grant_frames();
610 /* Determine the maximum number of frames required for the
611 * grant reference free list on the current hypervisor.
613 max_nr_glist_frames = (boot_max_nr_grant_frames *
614 GREFS_PER_GRANT_FRAME / RPP);
616 gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
617 GFP_KERNEL);
618 if (gnttab_list == NULL)
619 return -ENOMEM;
621 nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP;
622 for (i = 0; i < nr_glist_frames; i++) {
623 gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
624 if (gnttab_list[i] == NULL)
625 goto ini_nomem;
628 if (gnttab_resume() < 0)
629 return -ENODEV;
631 nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME;
633 for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
634 gnttab_entry(i) = i + 1;
636 gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
637 gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
638 gnttab_free_head = NR_RESERVED_ENTRIES;
640 printk("Grant table initialized\n");
641 return 0;
643 ini_nomem:
644 for (i--; i >= 0; i--)
645 free_page((unsigned long)gnttab_list[i]);
646 kfree(gnttab_list);
647 return -ENOMEM;
649 EXPORT_SYMBOL_GPL(gnttab_init);
651 static int __devinit __gnttab_init(void)
653 /* Delay grant-table initialization in the PV on HVM case */
654 if (xen_hvm_domain())
655 return 0;
657 if (!xen_pv_domain())
658 return -ENODEV;
660 return gnttab_init();
663 core_initcall(__gnttab_init);