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1/*
2 * linux/kernel/resource.c
3 *
4 * Copyright (C) 1999 Linus Torvalds
5 * Copyright (C) 1999 Martin Mares <mj@ucw.cz>
6 *
7 * Arbitrary resource management.
8 */
9
10#include <linux/export.h>
11#include <linux/errno.h>
12#include <linux/ioport.h>
13#include <linux/init.h>
14#include <linux/slab.h>
15#include <linux/spinlock.h>
16#include <linux/fs.h>
17#include <linux/proc_fs.h>
18#include <linux/sched.h>
19#include <linux/seq_file.h>
20#include <linux/device.h>
21#include <linux/pfn.h>
22#include <asm/io.h>
23
24
25struct resource ioport_resource = {
26 .name = "PCI IO",
27 .start = 0,
28 .end = IO_SPACE_LIMIT,
29 .flags = IORESOURCE_IO,
30};
31EXPORT_SYMBOL(ioport_resource);
32
33struct resource iomem_resource = {
34 .name = "PCI mem",
35 .start = 0,
36 .end = -1,
37 .flags = IORESOURCE_MEM,
38};
39EXPORT_SYMBOL(iomem_resource);
40
41/* constraints to be met while allocating resources */
42struct resource_constraint {
43 resource_size_t min, max, align;
44 resource_size_t (*alignf)(void *, const struct resource *,
45 resource_size_t, resource_size_t);
46 void *alignf_data;
47};
48
49static DEFINE_RWLOCK(resource_lock);
50
51static void *r_next(struct seq_file *m, void *v, loff_t *pos)
52{
53 struct resource *p = v;
54 (*pos)++;
55 if (p->child)
56 return p->child;
57 while (!p->sibling && p->parent)
58 p = p->parent;
59 return p->sibling;
60}
61
62#ifdef CONFIG_PROC_FS
63
64enum { MAX_IORES_LEVEL = 5 };
65
66static void *r_start(struct seq_file *m, loff_t *pos)
67 __acquires(resource_lock)
68{
69 struct resource *p = m->private;
70 loff_t l = 0;
71 read_lock(&resource_lock);
72 for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
73 ;
74 return p;
75}
76
77static void r_stop(struct seq_file *m, void *v)
78 __releases(resource_lock)
79{
80 read_unlock(&resource_lock);
81}
82
83static int r_show(struct seq_file *m, void *v)
84{
85 struct resource *root = m->private;
86 struct resource *r = v, *p;
87 int width = root->end < 0x10000 ? 4 : 8;
88 int depth;
89
90 for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
91 if (p->parent == root)
92 break;
93 seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
94 depth * 2, "",
95 width, (unsigned long long) r->start,
96 width, (unsigned long long) r->end,
97 r->name ? r->name : "<BAD>");
98 return 0;
99}
100
101static const struct seq_operations resource_op = {
102 .start = r_start,
103 .next = r_next,
104 .stop = r_stop,
105 .show = r_show,
106};
107
108static int ioports_open(struct inode *inode, struct file *file)
109{
110 int res = seq_open(file, &resource_op);
111 if (!res) {
112 struct seq_file *m = file->private_data;
113 m->private = &ioport_resource;
114 }
115 return res;
116}
117
118static int iomem_open(struct inode *inode, struct file *file)
119{
120 int res = seq_open(file, &resource_op);
121 if (!res) {
122 struct seq_file *m = file->private_data;
123 m->private = &iomem_resource;
124 }
125 return res;
126}
127
128static const struct file_operations proc_ioports_operations = {
129 .open = ioports_open,
130 .read = seq_read,
131 .llseek = seq_lseek,
132 .release = seq_release,
133};
134
135static const struct file_operations proc_iomem_operations = {
136 .open = iomem_open,
137 .read = seq_read,
138 .llseek = seq_lseek,
139 .release = seq_release,
140};
141
142static int __init ioresources_init(void)
143{
144 proc_create("ioports", 0, NULL, &proc_ioports_operations);
145 proc_create("iomem", 0, NULL, &proc_iomem_operations);
146 return 0;
147}
148__initcall(ioresources_init);
149
150#endif /* CONFIG_PROC_FS */
151
152/* Return the conflict entry if you can't request it */
153static struct resource * __request_resource(struct resource *root, struct resource *new)
154{
155 resource_size_t start = new->start;
156 resource_size_t end = new->end;
157 struct resource *tmp, **p;
158
159 if (end < start)
160 return root;
161 if (start < root->start)
162 return root;
163 if (end > root->end)
164 return root;
165 p = &root->child;
166 for (;;) {
167 tmp = *p;
168 if (!tmp || tmp->start > end) {
169 new->sibling = tmp;
170 *p = new;
171 new->parent = root;
172 return NULL;
173 }
174 p = &tmp->sibling;
175 if (tmp->end < start)
176 continue;
177 return tmp;
178 }
179}
180
181static int __release_resource(struct resource *old)
182{
183 struct resource *tmp, **p;
184
185 p = &old->parent->child;
186 for (;;) {
187 tmp = *p;
188 if (!tmp)
189 break;
190 if (tmp == old) {
191 *p = tmp->sibling;
192 old->parent = NULL;
193 return 0;
194 }
195 p = &tmp->sibling;
196 }
197 return -EINVAL;
198}
199
200static void __release_child_resources(struct resource *r)
201{
202 struct resource *tmp, *p;
203 resource_size_t size;
204
205 p = r->child;
206 r->child = NULL;
207 while (p) {
208 tmp = p;
209 p = p->sibling;
210
211 tmp->parent = NULL;
212 tmp->sibling = NULL;
213 __release_child_resources(tmp);
214
215 printk(KERN_DEBUG "release child resource %pR\n", tmp);
216 /* need to restore size, and keep flags */
217 size = resource_size(tmp);
218 tmp->start = 0;
219 tmp->end = size - 1;
220 }
221}
222
223void release_child_resources(struct resource *r)
224{
225 write_lock(&resource_lock);
226 __release_child_resources(r);
227 write_unlock(&resource_lock);
228}
229
230/**
231 * request_resource_conflict - request and reserve an I/O or memory resource
232 * @root: root resource descriptor
233 * @new: resource descriptor desired by caller
234 *
235 * Returns 0 for success, conflict resource on error.
236 */
237struct resource *request_resource_conflict(struct resource *root, struct resource *new)
238{
239 struct resource *conflict;
240
241 write_lock(&resource_lock);
242 conflict = __request_resource(root, new);
243 write_unlock(&resource_lock);
244 return conflict;
245}
246
247/**
248 * request_resource - request and reserve an I/O or memory resource
249 * @root: root resource descriptor
250 * @new: resource descriptor desired by caller
251 *
252 * Returns 0 for success, negative error code on error.
253 */
254int request_resource(struct resource *root, struct resource *new)
255{
256 struct resource *conflict;
257
258 conflict = request_resource_conflict(root, new);
259 return conflict ? -EBUSY : 0;
260}
261
262EXPORT_SYMBOL(request_resource);
263
264/**
265 * release_resource - release a previously reserved resource
266 * @old: resource pointer
267 */
268int release_resource(struct resource *old)
269{
270 int retval;
271
272 write_lock(&resource_lock);
273 retval = __release_resource(old);
274 write_unlock(&resource_lock);
275 return retval;
276}
277
278EXPORT_SYMBOL(release_resource);
279
280#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
281/*
282 * Finds the lowest memory reosurce exists within [res->start.res->end)
283 * the caller must specify res->start, res->end, res->flags and "name".
284 * If found, returns 0, res is overwritten, if not found, returns -1.
285 */
286static int find_next_system_ram(struct resource *res, char *name)
287{
288 resource_size_t start, end;
289 struct resource *p;
290
291 BUG_ON(!res);
292
293 start = res->start;
294 end = res->end;
295 BUG_ON(start >= end);
296
297 read_lock(&resource_lock);
298 for (p = iomem_resource.child; p ; p = p->sibling) {
299 /* system ram is just marked as IORESOURCE_MEM */
300 if (p->flags != res->flags)
301 continue;
302 if (name && strcmp(p->name, name))
303 continue;
304 if (p->start > end) {
305 p = NULL;
306 break;
307 }
308 if ((p->end >= start) && (p->start < end))
309 break;
310 }
311 read_unlock(&resource_lock);
312 if (!p)
313 return -1;
314 /* copy data */
315 if (res->start < p->start)
316 res->start = p->start;
317 if (res->end > p->end)
318 res->end = p->end;
319 return 0;
320}
321
322/*
323 * This function calls callback against all memory range of "System RAM"
324 * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
325 * Now, this function is only for "System RAM".
326 */
327int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
328 void *arg, int (*func)(unsigned long, unsigned long, void *))
329{
330 struct resource res;
331 unsigned long pfn, end_pfn;
332 u64 orig_end;
333 int ret = -1;
334
335 res.start = (u64) start_pfn << PAGE_SHIFT;
336 res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
337 res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
338 orig_end = res.end;
339 while ((res.start < res.end) &&
340 (find_next_system_ram(&res, "System RAM") >= 0)) {
341 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
342 end_pfn = (res.end + 1) >> PAGE_SHIFT;
343 if (end_pfn > pfn)
344 ret = (*func)(pfn, end_pfn - pfn, arg);
345 if (ret)
346 break;
347 res.start = res.end + 1;
348 res.end = orig_end;
349 }
350 return ret;
351}
352
353#endif
354
355static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
356{
357 return 1;
358}
359/*
360 * This generic page_is_ram() returns true if specified address is
361 * registered as "System RAM" in iomem_resource list.
362 */
363int __weak page_is_ram(unsigned long pfn)
364{
365 return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
366}
367
368void __weak arch_remove_reservations(struct resource *avail)
369{
370}
371
372static resource_size_t simple_align_resource(void *data,
373 const struct resource *avail,
374 resource_size_t size,
375 resource_size_t align)
376{
377 return avail->start;
378}
379
380static void resource_clip(struct resource *res, resource_size_t min,
381 resource_size_t max)
382{
383 if (res->start < min)
384 res->start = min;
385 if (res->end > max)
386 res->end = max;
387}
388
389static bool resource_contains(struct resource *res1, struct resource *res2)
390{
391 return res1->start <= res2->start && res1->end >= res2->end;
392}
393
394/*
395 * Find empty slot in the resource tree with the given range and
396 * alignment constraints
397 */
398static int __find_resource(struct resource *root, struct resource *old,
399 struct resource *new,
400 resource_size_t size,
401 struct resource_constraint *constraint)
402{
403 struct resource *this = root->child;
404 struct resource tmp = *new, avail, alloc;
405
406 tmp.flags = new->flags;
407 tmp.start = root->start;
408 /*
409 * Skip past an allocated resource that starts at 0, since the assignment
410 * of this->start - 1 to tmp->end below would cause an underflow.
411 */
412 if (this && this->start == root->start) {
413 tmp.start = (this == old) ? old->start : this->end + 1;
414 this = this->sibling;
415 }
416 for(;;) {
417 if (this)
418 tmp.end = (this == old) ? this->end : this->start - 1;
419 else
420 tmp.end = root->end;
421
422 if (tmp.end < tmp.start)
423 goto next;
424
425 resource_clip(&tmp, constraint->min, constraint->max);
426 arch_remove_reservations(&tmp);
427
428 /* Check for overflow after ALIGN() */
429 avail = *new;
430 avail.start = ALIGN(tmp.start, constraint->align);
431 avail.end = tmp.end;
432 if (avail.start >= tmp.start) {
433 alloc.start = constraint->alignf(constraint->alignf_data, &avail,
434 size, constraint->align);
435 alloc.end = alloc.start + size - 1;
436 if (resource_contains(&avail, &alloc)) {
437 new->start = alloc.start;
438 new->end = alloc.end;
439 return 0;
440 }
441 }
442
443next: if (!this || this->end == root->end)
444 break;
445
446 if (this != old)
447 tmp.start = this->end + 1;
448 this = this->sibling;
449 }
450 return -EBUSY;
451}
452
453/*
454 * Find empty slot in the resource tree given range and alignment.
455 */
456static int find_resource(struct resource *root, struct resource *new,
457 resource_size_t size,
458 struct resource_constraint *constraint)
459{
460 return __find_resource(root, NULL, new, size, constraint);
461}
462
463/**
464 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
465 * The resource will be relocated if the new size cannot be reallocated in the
466 * current location.
467 *
468 * @root: root resource descriptor
469 * @old: resource descriptor desired by caller
470 * @newsize: new size of the resource descriptor
471 * @constraint: the size and alignment constraints to be met.
472 */
473int reallocate_resource(struct resource *root, struct resource *old,
474 resource_size_t newsize,
475 struct resource_constraint *constraint)
476{
477 int err=0;
478 struct resource new = *old;
479 struct resource *conflict;
480
481 write_lock(&resource_lock);
482
483 if ((err = __find_resource(root, old, &new, newsize, constraint)))
484 goto out;
485
486 if (resource_contains(&new, old)) {
487 old->start = new.start;
488 old->end = new.end;
489 goto out;
490 }
491
492 if (old->child) {
493 err = -EBUSY;
494 goto out;
495 }
496
497 if (resource_contains(old, &new)) {
498 old->start = new.start;
499 old->end = new.end;
500 } else {
501 __release_resource(old);
502 *old = new;
503 conflict = __request_resource(root, old);
504 BUG_ON(conflict);
505 }
506out:
507 write_unlock(&resource_lock);
508 return err;
509}
510
511
512/**
513 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
514 * The resource will be reallocated with a new size if it was already allocated
515 * @root: root resource descriptor
516 * @new: resource descriptor desired by caller
517 * @size: requested resource region size
518 * @min: minimum boundary to allocate
519 * @max: maximum boundary to allocate
520 * @align: alignment requested, in bytes
521 * @alignf: alignment function, optional, called if not NULL
522 * @alignf_data: arbitrary data to pass to the @alignf function
523 */
524int allocate_resource(struct resource *root, struct resource *new,
525 resource_size_t size, resource_size_t min,
526 resource_size_t max, resource_size_t align,
527 resource_size_t (*alignf)(void *,
528 const struct resource *,
529 resource_size_t,
530 resource_size_t),
531 void *alignf_data)
532{
533 int err;
534 struct resource_constraint constraint;
535
536 if (!alignf)
537 alignf = simple_align_resource;
538
539 constraint.min = min;
540 constraint.max = max;
541 constraint.align = align;
542 constraint.alignf = alignf;
543 constraint.alignf_data = alignf_data;
544
545 if ( new->parent ) {
546 /* resource is already allocated, try reallocating with
547 the new constraints */
548 return reallocate_resource(root, new, size, &constraint);
549 }
550
551 write_lock(&resource_lock);
552 err = find_resource(root, new, size, &constraint);
553 if (err >= 0 && __request_resource(root, new))
554 err = -EBUSY;
555 write_unlock(&resource_lock);
556 return err;
557}
558
559EXPORT_SYMBOL(allocate_resource);
560
561/**
562 * lookup_resource - find an existing resource by a resource start address
563 * @root: root resource descriptor
564 * @start: resource start address
565 *
566 * Returns a pointer to the resource if found, NULL otherwise
567 */
568struct resource *lookup_resource(struct resource *root, resource_size_t start)
569{
570 struct resource *res;
571
572 read_lock(&resource_lock);
573 for (res = root->child; res; res = res->sibling) {
574 if (res->start == start)
575 break;
576 }
577 read_unlock(&resource_lock);
578
579 return res;
580}
581
582/*
583 * Insert a resource into the resource tree. If successful, return NULL,
584 * otherwise return the conflicting resource (compare to __request_resource())
585 */
586static struct resource * __insert_resource(struct resource *parent, struct resource *new)
587{
588 struct resource *first, *next;
589
590 for (;; parent = first) {
591 first = __request_resource(parent, new);
592 if (!first)
593 return first;
594
595 if (first == parent)
596 return first;
597 if (WARN_ON(first == new)) /* duplicated insertion */
598 return first;
599
600 if ((first->start > new->start) || (first->end < new->end))
601 break;
602 if ((first->start == new->start) && (first->end == new->end))
603 break;
604 }
605
606 for (next = first; ; next = next->sibling) {
607 /* Partial overlap? Bad, and unfixable */
608 if (next->start < new->start || next->end > new->end)
609 return next;
610 if (!next->sibling)
611 break;
612 if (next->sibling->start > new->end)
613 break;
614 }
615
616 new->parent = parent;
617 new->sibling = next->sibling;
618 new->child = first;
619
620 next->sibling = NULL;
621 for (next = first; next; next = next->sibling)
622 next->parent = new;
623
624 if (parent->child == first) {
625 parent->child = new;
626 } else {
627 next = parent->child;
628 while (next->sibling != first)
629 next = next->sibling;
630 next->sibling = new;
631 }
632 return NULL;
633}
634
635/**
636 * insert_resource_conflict - Inserts resource in the resource tree
637 * @parent: parent of the new resource
638 * @new: new resource to insert
639 *
640 * Returns 0 on success, conflict resource if the resource can't be inserted.
641 *
642 * This function is equivalent to request_resource_conflict when no conflict
643 * happens. If a conflict happens, and the conflicting resources
644 * entirely fit within the range of the new resource, then the new
645 * resource is inserted and the conflicting resources become children of
646 * the new resource.
647 */
648struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
649{
650 struct resource *conflict;
651
652 write_lock(&resource_lock);
653 conflict = __insert_resource(parent, new);
654 write_unlock(&resource_lock);
655 return conflict;
656}
657
658/**
659 * insert_resource - Inserts a resource in the resource tree
660 * @parent: parent of the new resource
661 * @new: new resource to insert
662 *
663 * Returns 0 on success, -EBUSY if the resource can't be inserted.
664 */
665int insert_resource(struct resource *parent, struct resource *new)
666{
667 struct resource *conflict;
668
669 conflict = insert_resource_conflict(parent, new);
670 return conflict ? -EBUSY : 0;
671}
672
673/**
674 * insert_resource_expand_to_fit - Insert a resource into the resource tree
675 * @root: root resource descriptor
676 * @new: new resource to insert
677 *
678 * Insert a resource into the resource tree, possibly expanding it in order
679 * to make it encompass any conflicting resources.
680 */
681void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
682{
683 if (new->parent)
684 return;
685
686 write_lock(&resource_lock);
687 for (;;) {
688 struct resource *conflict;
689
690 conflict = __insert_resource(root, new);
691 if (!conflict)
692 break;
693 if (conflict == root)
694 break;
695
696 /* Ok, expand resource to cover the conflict, then try again .. */
697 if (conflict->start < new->start)
698 new->start = conflict->start;
699 if (conflict->end > new->end)
700 new->end = conflict->end;
701
702 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
703 }
704 write_unlock(&resource_lock);
705}
706
707/**
708 * adjust_resource - modify a resource's start and size
709 * @res: resource to modify
710 * @start: new start value
711 * @size: new size
712 *
713 * Given an existing resource, change its start and size to match the
714 * arguments. Returns 0 on success, -EBUSY if it can't fit.
715 * Existing children of the resource are assumed to be immutable.
716 */
717int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
718{
719 struct resource *tmp, *parent = res->parent;
720 resource_size_t end = start + size - 1;
721 int result = -EBUSY;
722
723 write_lock(&resource_lock);
724
725 if ((start < parent->start) || (end > parent->end))
726 goto out;
727
728 for (tmp = res->child; tmp; tmp = tmp->sibling) {
729 if ((tmp->start < start) || (tmp->end > end))
730 goto out;
731 }
732
733 if (res->sibling && (res->sibling->start <= end))
734 goto out;
735
736 tmp = parent->child;
737 if (tmp != res) {
738 while (tmp->sibling != res)
739 tmp = tmp->sibling;
740 if (start <= tmp->end)
741 goto out;
742 }
743
744 res->start = start;
745 res->end = end;
746 result = 0;
747
748 out:
749 write_unlock(&resource_lock);
750 return result;
751}
752EXPORT_SYMBOL(adjust_resource);
753
754static void __init __reserve_region_with_split(struct resource *root,
755 resource_size_t start, resource_size_t end,
756 const char *name)
757{
758 struct resource *parent = root;
759 struct resource *conflict;
760 struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
761
762 if (!res)
763 return;
764
765 res->name = name;
766 res->start = start;
767 res->end = end;
768 res->flags = IORESOURCE_BUSY;
769
770 conflict = __request_resource(parent, res);
771 if (!conflict)
772 return;
773
774 /* failed, split and try again */
775 kfree(res);
776
777 /* conflict covered whole area */
778 if (conflict->start <= start && conflict->end >= end)
779 return;
780
781 if (conflict->start > start)
782 __reserve_region_with_split(root, start, conflict->start-1, name);
783 if (conflict->end < end)
784 __reserve_region_with_split(root, conflict->end+1, end, name);
785}
786
787void __init reserve_region_with_split(struct resource *root,
788 resource_size_t start, resource_size_t end,
789 const char *name)
790{
791 write_lock(&resource_lock);
792 __reserve_region_with_split(root, start, end, name);
793 write_unlock(&resource_lock);
794}
795
796/**
797 * resource_alignment - calculate resource's alignment
798 * @res: resource pointer
799 *
800 * Returns alignment on success, 0 (invalid alignment) on failure.
801 */
802resource_size_t resource_alignment(struct resource *res)
803{
804 switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
805 case IORESOURCE_SIZEALIGN:
806 return resource_size(res);
807 case IORESOURCE_STARTALIGN:
808 return res->start;
809 default:
810 return 0;
811 }
812}
813
814/*
815 * This is compatibility stuff for IO resources.
816 *
817 * Note how this, unlike the above, knows about
818 * the IO flag meanings (busy etc).
819 *
820 * request_region creates a new busy region.
821 *
822 * check_region returns non-zero if the area is already busy.
823 *
824 * release_region releases a matching busy region.
825 */
826
827static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
828
829/**
830 * __request_region - create a new busy resource region
831 * @parent: parent resource descriptor
832 * @start: resource start address
833 * @n: resource region size
834 * @name: reserving caller's ID string
835 * @flags: IO resource flags
836 */
837struct resource * __request_region(struct resource *parent,
838 resource_size_t start, resource_size_t n,
839 const char *name, int flags)
840{
841 DECLARE_WAITQUEUE(wait, current);
842 struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
843
844 if (!res)
845 return NULL;
846
847 res->name = name;
848 res->start = start;
849 res->end = start + n - 1;
850 res->flags = IORESOURCE_BUSY;
851 res->flags |= flags;
852
853 write_lock(&resource_lock);
854
855 for (;;) {
856 struct resource *conflict;
857
858 conflict = __request_resource(parent, res);
859 if (!conflict)
860 break;
861 if (conflict != parent) {
862 parent = conflict;
863 if (!(conflict->flags & IORESOURCE_BUSY))
864 continue;
865 }
866 if (conflict->flags & flags & IORESOURCE_MUXED) {
867 add_wait_queue(&muxed_resource_wait, &wait);
868 write_unlock(&resource_lock);
869 set_current_state(TASK_UNINTERRUPTIBLE);
870 schedule();
871 remove_wait_queue(&muxed_resource_wait, &wait);
872 write_lock(&resource_lock);
873 continue;
874 }
875 /* Uhhuh, that didn't work out.. */
876 kfree(res);
877 res = NULL;
878 break;
879 }
880 write_unlock(&resource_lock);
881 return res;
882}
883EXPORT_SYMBOL(__request_region);
884
885/**
886 * __check_region - check if a resource region is busy or free
887 * @parent: parent resource descriptor
888 * @start: resource start address
889 * @n: resource region size
890 *
891 * Returns 0 if the region is free at the moment it is checked,
892 * returns %-EBUSY if the region is busy.
893 *
894 * NOTE:
895 * This function is deprecated because its use is racy.
896 * Even if it returns 0, a subsequent call to request_region()
897 * may fail because another driver etc. just allocated the region.
898 * Do NOT use it. It will be removed from the kernel.
899 */
900int __check_region(struct resource *parent, resource_size_t start,
901 resource_size_t n)
902{
903 struct resource * res;
904
905 res = __request_region(parent, start, n, "check-region", 0);
906 if (!res)
907 return -EBUSY;
908
909 release_resource(res);
910 kfree(res);
911 return 0;
912}
913EXPORT_SYMBOL(__check_region);
914
915/**
916 * __release_region - release a previously reserved resource region
917 * @parent: parent resource descriptor
918 * @start: resource start address
919 * @n: resource region size
920 *
921 * The described resource region must match a currently busy region.
922 */
923void __release_region(struct resource *parent, resource_size_t start,
924 resource_size_t n)
925{
926 struct resource **p;
927 resource_size_t end;
928
929 p = &parent->child;
930 end = start + n - 1;
931
932 write_lock(&resource_lock);
933
934 for (;;) {
935 struct resource *res = *p;
936
937 if (!res)
938 break;
939 if (res->start <= start && res->end >= end) {
940 if (!(res->flags & IORESOURCE_BUSY)) {
941 p = &res->child;
942 continue;
943 }
944 if (res->start != start || res->end != end)
945 break;
946 *p = res->sibling;
947 write_unlock(&resource_lock);
948 if (res->flags & IORESOURCE_MUXED)
949 wake_up(&muxed_resource_wait);
950 kfree(res);
951 return;
952 }
953 p = &res->sibling;
954 }
955
956 write_unlock(&resource_lock);
957
958 printk(KERN_WARNING "Trying to free nonexistent resource "
959 "<%016llx-%016llx>\n", (unsigned long long)start,
960 (unsigned long long)end);
961}
962EXPORT_SYMBOL(__release_region);
963
964/*
965 * Managed region resource
966 */
967struct region_devres {
968 struct resource *parent;
969 resource_size_t start;
970 resource_size_t n;
971};
972
973static void devm_region_release(struct device *dev, void *res)
974{
975 struct region_devres *this = res;
976
977 __release_region(this->parent, this->start, this->n);
978}
979
980static int devm_region_match(struct device *dev, void *res, void *match_data)
981{
982 struct region_devres *this = res, *match = match_data;
983
984 return this->parent == match->parent &&
985 this->start == match->start && this->n == match->n;
986}
987
988struct resource * __devm_request_region(struct device *dev,
989 struct resource *parent, resource_size_t start,
990 resource_size_t n, const char *name)
991{
992 struct region_devres *dr = NULL;
993 struct resource *res;
994
995 dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
996 GFP_KERNEL);
997 if (!dr)
998 return NULL;
999
1000 dr->parent = parent;
1001 dr->start = start;
1002 dr->n = n;
1003
1004 res = __request_region(parent, start, n, name, 0);
1005 if (res)
1006 devres_add(dev, dr);
1007 else
1008 devres_free(dr);
1009
1010 return res;
1011}
1012EXPORT_SYMBOL(__devm_request_region);
1013
1014void __devm_release_region(struct device *dev, struct resource *parent,
1015 resource_size_t start, resource_size_t n)
1016{
1017 struct region_devres match_data = { parent, start, n };
1018
1019 __release_region(parent, start, n);
1020 WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1021 &match_data));
1022}
1023EXPORT_SYMBOL(__devm_release_region);
1024
1025/*
1026 * Called from init/main.c to reserve IO ports.
1027 */
1028#define MAXRESERVE 4
1029static int __init reserve_setup(char *str)
1030{
1031 static int reserved;
1032 static struct resource reserve[MAXRESERVE];
1033
1034 for (;;) {
1035 unsigned int io_start, io_num;
1036 int x = reserved;
1037
1038 if (get_option (&str, &io_start) != 2)
1039 break;
1040 if (get_option (&str, &io_num) == 0)
1041 break;
1042 if (x < MAXRESERVE) {
1043 struct resource *res = reserve + x;
1044 res->name = "reserved";
1045 res->start = io_start;
1046 res->end = io_start + io_num - 1;
1047 res->flags = IORESOURCE_BUSY;
1048 res->child = NULL;
1049 if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1050 reserved = x+1;
1051 }
1052 }
1053 return 1;
1054}
1055
1056__setup("reserve=", reserve_setup);
1057
1058/*
1059 * Check if the requested addr and size spans more than any slot in the
1060 * iomem resource tree.
1061 */
1062int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1063{
1064 struct resource *p = &iomem_resource;
1065 int err = 0;
1066 loff_t l;
1067
1068 read_lock(&resource_lock);
1069 for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1070 /*
1071 * We can probably skip the resources without
1072 * IORESOURCE_IO attribute?
1073 */
1074 if (p->start >= addr + size)
1075 continue;
1076 if (p->end < addr)
1077 continue;
1078 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1079 PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1080 continue;
1081 /*
1082 * if a resource is "BUSY", it's not a hardware resource
1083 * but a driver mapping of such a resource; we don't want
1084 * to warn for those; some drivers legitimately map only
1085 * partial hardware resources. (example: vesafb)
1086 */
1087 if (p->flags & IORESOURCE_BUSY)
1088 continue;
1089
1090 printk(KERN_WARNING "resource map sanity check conflict: "
1091 "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1092 (unsigned long long)addr,
1093 (unsigned long long)(addr + size - 1),
1094 (unsigned long long)p->start,
1095 (unsigned long long)p->end,
1096 p->name);
1097 err = -1;
1098 break;
1099 }
1100 read_unlock(&resource_lock);
1101
1102 return err;
1103}
1104
1105#ifdef CONFIG_STRICT_DEVMEM
1106static int strict_iomem_checks = 1;
1107#else
1108static int strict_iomem_checks;
1109#endif
1110
1111/*
1112 * check if an address is reserved in the iomem resource tree
1113 * returns 1 if reserved, 0 if not reserved.
1114 */
1115int iomem_is_exclusive(u64 addr)
1116{
1117 struct resource *p = &iomem_resource;
1118 int err = 0;
1119 loff_t l;
1120 int size = PAGE_SIZE;
1121
1122 if (!strict_iomem_checks)
1123 return 0;
1124
1125 addr = addr & PAGE_MASK;
1126
1127 read_lock(&resource_lock);
1128 for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1129 /*
1130 * We can probably skip the resources without
1131 * IORESOURCE_IO attribute?
1132 */
1133 if (p->start >= addr + size)
1134 break;
1135 if (p->end < addr)
1136 continue;
1137 if (p->flags & IORESOURCE_BUSY &&
1138 p->flags & IORESOURCE_EXCLUSIVE) {
1139 err = 1;
1140 break;
1141 }
1142 }
1143 read_unlock(&resource_lock);
1144
1145 return err;
1146}
1147
1148static int __init strict_iomem(char *str)
1149{
1150 if (strstr(str, "relaxed"))
1151 strict_iomem_checks = 0;
1152 if (strstr(str, "strict"))
1153 strict_iomem_checks = 1;
1154 return 1;
1155}
1156
1157__setup("iomem=", strict_iomem);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/kernel/resource.c
4 *
5 * Copyright (C) 1999 Linus Torvalds
6 * Copyright (C) 1999 Martin Mares <mj@ucw.cz>
7 *
8 * Arbitrary resource management.
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/export.h>
14#include <linux/errno.h>
15#include <linux/ioport.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <linux/spinlock.h>
19#include <linux/fs.h>
20#include <linux/proc_fs.h>
21#include <linux/pseudo_fs.h>
22#include <linux/sched.h>
23#include <linux/seq_file.h>
24#include <linux/device.h>
25#include <linux/pfn.h>
26#include <linux/mm.h>
27#include <linux/mount.h>
28#include <linux/resource_ext.h>
29#include <uapi/linux/magic.h>
30#include <linux/string.h>
31#include <linux/vmalloc.h>
32#include <asm/io.h>
33
34
35struct resource ioport_resource = {
36 .name = "PCI IO",
37 .start = 0,
38 .end = IO_SPACE_LIMIT,
39 .flags = IORESOURCE_IO,
40};
41EXPORT_SYMBOL(ioport_resource);
42
43struct resource iomem_resource = {
44 .name = "PCI mem",
45 .start = 0,
46 .end = -1,
47 .flags = IORESOURCE_MEM,
48};
49EXPORT_SYMBOL(iomem_resource);
50
51/* constraints to be met while allocating resources */
52struct resource_constraint {
53 resource_size_t min, max, align;
54 resource_size_t (*alignf)(void *, const struct resource *,
55 resource_size_t, resource_size_t);
56 void *alignf_data;
57};
58
59static DEFINE_RWLOCK(resource_lock);
60
61static struct resource *next_resource(struct resource *p, bool skip_children)
62{
63 if (!skip_children && p->child)
64 return p->child;
65 while (!p->sibling && p->parent)
66 p = p->parent;
67 return p->sibling;
68}
69
70#define for_each_resource(_root, _p, _skip_children) \
71 for ((_p) = (_root)->child; (_p); (_p) = next_resource(_p, _skip_children))
72
73#ifdef CONFIG_PROC_FS
74
75enum { MAX_IORES_LEVEL = 5 };
76
77static void *r_start(struct seq_file *m, loff_t *pos)
78 __acquires(resource_lock)
79{
80 struct resource *root = pde_data(file_inode(m->file));
81 struct resource *p;
82 loff_t l = *pos;
83
84 read_lock(&resource_lock);
85 for_each_resource(root, p, false) {
86 if (l-- == 0)
87 break;
88 }
89
90 return p;
91}
92
93static void *r_next(struct seq_file *m, void *v, loff_t *pos)
94{
95 struct resource *p = v;
96
97 (*pos)++;
98
99 return (void *)next_resource(p, false);
100}
101
102static void r_stop(struct seq_file *m, void *v)
103 __releases(resource_lock)
104{
105 read_unlock(&resource_lock);
106}
107
108static int r_show(struct seq_file *m, void *v)
109{
110 struct resource *root = pde_data(file_inode(m->file));
111 struct resource *r = v, *p;
112 unsigned long long start, end;
113 int width = root->end < 0x10000 ? 4 : 8;
114 int depth;
115
116 for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
117 if (p->parent == root)
118 break;
119
120 if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
121 start = r->start;
122 end = r->end;
123 } else {
124 start = end = 0;
125 }
126
127 seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
128 depth * 2, "",
129 width, start,
130 width, end,
131 r->name ? r->name : "<BAD>");
132 return 0;
133}
134
135static const struct seq_operations resource_op = {
136 .start = r_start,
137 .next = r_next,
138 .stop = r_stop,
139 .show = r_show,
140};
141
142static int __init ioresources_init(void)
143{
144 proc_create_seq_data("ioports", 0, NULL, &resource_op,
145 &ioport_resource);
146 proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
147 return 0;
148}
149__initcall(ioresources_init);
150
151#endif /* CONFIG_PROC_FS */
152
153static void free_resource(struct resource *res)
154{
155 /**
156 * If the resource was allocated using memblock early during boot
157 * we'll leak it here: we can only return full pages back to the
158 * buddy and trying to be smart and reusing them eventually in
159 * alloc_resource() overcomplicates resource handling.
160 */
161 if (res && PageSlab(virt_to_head_page(res)))
162 kfree(res);
163}
164
165static struct resource *alloc_resource(gfp_t flags)
166{
167 return kzalloc(sizeof(struct resource), flags);
168}
169
170/* Return the conflict entry if you can't request it */
171static struct resource * __request_resource(struct resource *root, struct resource *new)
172{
173 resource_size_t start = new->start;
174 resource_size_t end = new->end;
175 struct resource *tmp, **p;
176
177 if (end < start)
178 return root;
179 if (start < root->start)
180 return root;
181 if (end > root->end)
182 return root;
183 p = &root->child;
184 for (;;) {
185 tmp = *p;
186 if (!tmp || tmp->start > end) {
187 new->sibling = tmp;
188 *p = new;
189 new->parent = root;
190 return NULL;
191 }
192 p = &tmp->sibling;
193 if (tmp->end < start)
194 continue;
195 return tmp;
196 }
197}
198
199static int __release_resource(struct resource *old, bool release_child)
200{
201 struct resource *tmp, **p, *chd;
202
203 p = &old->parent->child;
204 for (;;) {
205 tmp = *p;
206 if (!tmp)
207 break;
208 if (tmp == old) {
209 if (release_child || !(tmp->child)) {
210 *p = tmp->sibling;
211 } else {
212 for (chd = tmp->child;; chd = chd->sibling) {
213 chd->parent = tmp->parent;
214 if (!(chd->sibling))
215 break;
216 }
217 *p = tmp->child;
218 chd->sibling = tmp->sibling;
219 }
220 old->parent = NULL;
221 return 0;
222 }
223 p = &tmp->sibling;
224 }
225 return -EINVAL;
226}
227
228static void __release_child_resources(struct resource *r)
229{
230 struct resource *tmp, *p;
231 resource_size_t size;
232
233 p = r->child;
234 r->child = NULL;
235 while (p) {
236 tmp = p;
237 p = p->sibling;
238
239 tmp->parent = NULL;
240 tmp->sibling = NULL;
241 __release_child_resources(tmp);
242
243 printk(KERN_DEBUG "release child resource %pR\n", tmp);
244 /* need to restore size, and keep flags */
245 size = resource_size(tmp);
246 tmp->start = 0;
247 tmp->end = size - 1;
248 }
249}
250
251void release_child_resources(struct resource *r)
252{
253 write_lock(&resource_lock);
254 __release_child_resources(r);
255 write_unlock(&resource_lock);
256}
257
258/**
259 * request_resource_conflict - request and reserve an I/O or memory resource
260 * @root: root resource descriptor
261 * @new: resource descriptor desired by caller
262 *
263 * Returns 0 for success, conflict resource on error.
264 */
265struct resource *request_resource_conflict(struct resource *root, struct resource *new)
266{
267 struct resource *conflict;
268
269 write_lock(&resource_lock);
270 conflict = __request_resource(root, new);
271 write_unlock(&resource_lock);
272 return conflict;
273}
274
275/**
276 * request_resource - request and reserve an I/O or memory resource
277 * @root: root resource descriptor
278 * @new: resource descriptor desired by caller
279 *
280 * Returns 0 for success, negative error code on error.
281 */
282int request_resource(struct resource *root, struct resource *new)
283{
284 struct resource *conflict;
285
286 conflict = request_resource_conflict(root, new);
287 return conflict ? -EBUSY : 0;
288}
289
290EXPORT_SYMBOL(request_resource);
291
292/**
293 * release_resource - release a previously reserved resource
294 * @old: resource pointer
295 */
296int release_resource(struct resource *old)
297{
298 int retval;
299
300 write_lock(&resource_lock);
301 retval = __release_resource(old, true);
302 write_unlock(&resource_lock);
303 return retval;
304}
305
306EXPORT_SYMBOL(release_resource);
307
308/**
309 * find_next_iomem_res - Finds the lowest iomem resource that covers part of
310 * [@start..@end].
311 *
312 * If a resource is found, returns 0 and @*res is overwritten with the part
313 * of the resource that's within [@start..@end]; if none is found, returns
314 * -ENODEV. Returns -EINVAL for invalid parameters.
315 *
316 * @start: start address of the resource searched for
317 * @end: end address of same resource
318 * @flags: flags which the resource must have
319 * @desc: descriptor the resource must have
320 * @res: return ptr, if resource found
321 *
322 * The caller must specify @start, @end, @flags, and @desc
323 * (which may be IORES_DESC_NONE).
324 */
325static int find_next_iomem_res(resource_size_t start, resource_size_t end,
326 unsigned long flags, unsigned long desc,
327 struct resource *res)
328{
329 struct resource *p;
330
331 if (!res)
332 return -EINVAL;
333
334 if (start >= end)
335 return -EINVAL;
336
337 read_lock(&resource_lock);
338
339 for_each_resource(&iomem_resource, p, false) {
340 /* If we passed the resource we are looking for, stop */
341 if (p->start > end) {
342 p = NULL;
343 break;
344 }
345
346 /* Skip until we find a range that matches what we look for */
347 if (p->end < start)
348 continue;
349
350 if ((p->flags & flags) != flags)
351 continue;
352 if ((desc != IORES_DESC_NONE) && (desc != p->desc))
353 continue;
354
355 /* Found a match, break */
356 break;
357 }
358
359 if (p) {
360 /* copy data */
361 *res = (struct resource) {
362 .start = max(start, p->start),
363 .end = min(end, p->end),
364 .flags = p->flags,
365 .desc = p->desc,
366 .parent = p->parent,
367 };
368 }
369
370 read_unlock(&resource_lock);
371 return p ? 0 : -ENODEV;
372}
373
374static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
375 unsigned long flags, unsigned long desc,
376 void *arg,
377 int (*func)(struct resource *, void *))
378{
379 struct resource res;
380 int ret = -EINVAL;
381
382 while (start < end &&
383 !find_next_iomem_res(start, end, flags, desc, &res)) {
384 ret = (*func)(&res, arg);
385 if (ret)
386 break;
387
388 start = res.end + 1;
389 }
390
391 return ret;
392}
393
394/**
395 * walk_iomem_res_desc - Walks through iomem resources and calls func()
396 * with matching resource ranges.
397 * *
398 * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
399 * @flags: I/O resource flags
400 * @start: start addr
401 * @end: end addr
402 * @arg: function argument for the callback @func
403 * @func: callback function that is called for each qualifying resource area
404 *
405 * All the memory ranges which overlap start,end and also match flags and
406 * desc are valid candidates.
407 *
408 * NOTE: For a new descriptor search, define a new IORES_DESC in
409 * <linux/ioport.h> and set it in 'desc' of a target resource entry.
410 */
411int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
412 u64 end, void *arg, int (*func)(struct resource *, void *))
413{
414 return __walk_iomem_res_desc(start, end, flags, desc, arg, func);
415}
416EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
417
418/*
419 * This function calls the @func callback against all memory ranges of type
420 * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
421 * Now, this function is only for System RAM, it deals with full ranges and
422 * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
423 * ranges.
424 */
425int walk_system_ram_res(u64 start, u64 end, void *arg,
426 int (*func)(struct resource *, void *))
427{
428 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
429
430 return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
431 func);
432}
433
434/*
435 * This function, being a variant of walk_system_ram_res(), calls the @func
436 * callback against all memory ranges of type System RAM which are marked as
437 * IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY in reversed order, i.e., from
438 * higher to lower.
439 */
440int walk_system_ram_res_rev(u64 start, u64 end, void *arg,
441 int (*func)(struct resource *, void *))
442{
443 struct resource res, *rams;
444 int rams_size = 16, i;
445 unsigned long flags;
446 int ret = -1;
447
448 /* create a list */
449 rams = kvcalloc(rams_size, sizeof(struct resource), GFP_KERNEL);
450 if (!rams)
451 return ret;
452
453 flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
454 i = 0;
455 while ((start < end) &&
456 (!find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res))) {
457 if (i >= rams_size) {
458 /* re-alloc */
459 struct resource *rams_new;
460
461 rams_new = kvrealloc(rams, rams_size * sizeof(struct resource),
462 (rams_size + 16) * sizeof(struct resource),
463 GFP_KERNEL);
464 if (!rams_new)
465 goto out;
466
467 rams = rams_new;
468 rams_size += 16;
469 }
470
471 rams[i].start = res.start;
472 rams[i++].end = res.end;
473
474 start = res.end + 1;
475 }
476
477 /* go reverse */
478 for (i--; i >= 0; i--) {
479 ret = (*func)(&rams[i], arg);
480 if (ret)
481 break;
482 }
483
484out:
485 kvfree(rams);
486 return ret;
487}
488
489/*
490 * This function calls the @func callback against all memory ranges, which
491 * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
492 */
493int walk_mem_res(u64 start, u64 end, void *arg,
494 int (*func)(struct resource *, void *))
495{
496 unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
497
498 return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
499 func);
500}
501
502/*
503 * This function calls the @func callback against all memory ranges of type
504 * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
505 * It is to be used only for System RAM.
506 */
507int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
508 void *arg, int (*func)(unsigned long, unsigned long, void *))
509{
510 resource_size_t start, end;
511 unsigned long flags;
512 struct resource res;
513 unsigned long pfn, end_pfn;
514 int ret = -EINVAL;
515
516 start = (u64) start_pfn << PAGE_SHIFT;
517 end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
518 flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
519 while (start < end &&
520 !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
521 pfn = PFN_UP(res.start);
522 end_pfn = PFN_DOWN(res.end + 1);
523 if (end_pfn > pfn)
524 ret = (*func)(pfn, end_pfn - pfn, arg);
525 if (ret)
526 break;
527 start = res.end + 1;
528 }
529 return ret;
530}
531
532static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
533{
534 return 1;
535}
536
537/*
538 * This generic page_is_ram() returns true if specified address is
539 * registered as System RAM in iomem_resource list.
540 */
541int __weak page_is_ram(unsigned long pfn)
542{
543 return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
544}
545EXPORT_SYMBOL_GPL(page_is_ram);
546
547static int __region_intersects(struct resource *parent, resource_size_t start,
548 size_t size, unsigned long flags,
549 unsigned long desc)
550{
551 struct resource res;
552 int type = 0; int other = 0;
553 struct resource *p;
554
555 res.start = start;
556 res.end = start + size - 1;
557
558 for (p = parent->child; p ; p = p->sibling) {
559 bool is_type = (((p->flags & flags) == flags) &&
560 ((desc == IORES_DESC_NONE) ||
561 (desc == p->desc)));
562
563 if (resource_overlaps(p, &res))
564 is_type ? type++ : other++;
565 }
566
567 if (type == 0)
568 return REGION_DISJOINT;
569
570 if (other == 0)
571 return REGION_INTERSECTS;
572
573 return REGION_MIXED;
574}
575
576/**
577 * region_intersects() - determine intersection of region with known resources
578 * @start: region start address
579 * @size: size of region
580 * @flags: flags of resource (in iomem_resource)
581 * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
582 *
583 * Check if the specified region partially overlaps or fully eclipses a
584 * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
585 * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
586 * return REGION_MIXED if the region overlaps @flags/@desc and another
587 * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
588 * and no other defined resource. Note that REGION_INTERSECTS is also
589 * returned in the case when the specified region overlaps RAM and undefined
590 * memory holes.
591 *
592 * region_intersect() is used by memory remapping functions to ensure
593 * the user is not remapping RAM and is a vast speed up over walking
594 * through the resource table page by page.
595 */
596int region_intersects(resource_size_t start, size_t size, unsigned long flags,
597 unsigned long desc)
598{
599 int ret;
600
601 read_lock(&resource_lock);
602 ret = __region_intersects(&iomem_resource, start, size, flags, desc);
603 read_unlock(&resource_lock);
604
605 return ret;
606}
607EXPORT_SYMBOL_GPL(region_intersects);
608
609void __weak arch_remove_reservations(struct resource *avail)
610{
611}
612
613static resource_size_t simple_align_resource(void *data,
614 const struct resource *avail,
615 resource_size_t size,
616 resource_size_t align)
617{
618 return avail->start;
619}
620
621static void resource_clip(struct resource *res, resource_size_t min,
622 resource_size_t max)
623{
624 if (res->start < min)
625 res->start = min;
626 if (res->end > max)
627 res->end = max;
628}
629
630/*
631 * Find empty slot in the resource tree with the given range and
632 * alignment constraints
633 */
634static int __find_resource(struct resource *root, struct resource *old,
635 struct resource *new,
636 resource_size_t size,
637 struct resource_constraint *constraint)
638{
639 struct resource *this = root->child;
640 struct resource tmp = *new, avail, alloc;
641
642 tmp.start = root->start;
643 /*
644 * Skip past an allocated resource that starts at 0, since the assignment
645 * of this->start - 1 to tmp->end below would cause an underflow.
646 */
647 if (this && this->start == root->start) {
648 tmp.start = (this == old) ? old->start : this->end + 1;
649 this = this->sibling;
650 }
651 for(;;) {
652 if (this)
653 tmp.end = (this == old) ? this->end : this->start - 1;
654 else
655 tmp.end = root->end;
656
657 if (tmp.end < tmp.start)
658 goto next;
659
660 resource_clip(&tmp, constraint->min, constraint->max);
661 arch_remove_reservations(&tmp);
662
663 /* Check for overflow after ALIGN() */
664 avail.start = ALIGN(tmp.start, constraint->align);
665 avail.end = tmp.end;
666 avail.flags = new->flags & ~IORESOURCE_UNSET;
667 if (avail.start >= tmp.start) {
668 alloc.flags = avail.flags;
669 alloc.start = constraint->alignf(constraint->alignf_data, &avail,
670 size, constraint->align);
671 alloc.end = alloc.start + size - 1;
672 if (alloc.start <= alloc.end &&
673 resource_contains(&avail, &alloc)) {
674 new->start = alloc.start;
675 new->end = alloc.end;
676 return 0;
677 }
678 }
679
680next: if (!this || this->end == root->end)
681 break;
682
683 if (this != old)
684 tmp.start = this->end + 1;
685 this = this->sibling;
686 }
687 return -EBUSY;
688}
689
690/*
691 * Find empty slot in the resource tree given range and alignment.
692 */
693static int find_resource(struct resource *root, struct resource *new,
694 resource_size_t size,
695 struct resource_constraint *constraint)
696{
697 return __find_resource(root, NULL, new, size, constraint);
698}
699
700/**
701 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
702 * The resource will be relocated if the new size cannot be reallocated in the
703 * current location.
704 *
705 * @root: root resource descriptor
706 * @old: resource descriptor desired by caller
707 * @newsize: new size of the resource descriptor
708 * @constraint: the size and alignment constraints to be met.
709 */
710static int reallocate_resource(struct resource *root, struct resource *old,
711 resource_size_t newsize,
712 struct resource_constraint *constraint)
713{
714 int err=0;
715 struct resource new = *old;
716 struct resource *conflict;
717
718 write_lock(&resource_lock);
719
720 if ((err = __find_resource(root, old, &new, newsize, constraint)))
721 goto out;
722
723 if (resource_contains(&new, old)) {
724 old->start = new.start;
725 old->end = new.end;
726 goto out;
727 }
728
729 if (old->child) {
730 err = -EBUSY;
731 goto out;
732 }
733
734 if (resource_contains(old, &new)) {
735 old->start = new.start;
736 old->end = new.end;
737 } else {
738 __release_resource(old, true);
739 *old = new;
740 conflict = __request_resource(root, old);
741 BUG_ON(conflict);
742 }
743out:
744 write_unlock(&resource_lock);
745 return err;
746}
747
748
749/**
750 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
751 * The resource will be reallocated with a new size if it was already allocated
752 * @root: root resource descriptor
753 * @new: resource descriptor desired by caller
754 * @size: requested resource region size
755 * @min: minimum boundary to allocate
756 * @max: maximum boundary to allocate
757 * @align: alignment requested, in bytes
758 * @alignf: alignment function, optional, called if not NULL
759 * @alignf_data: arbitrary data to pass to the @alignf function
760 */
761int allocate_resource(struct resource *root, struct resource *new,
762 resource_size_t size, resource_size_t min,
763 resource_size_t max, resource_size_t align,
764 resource_size_t (*alignf)(void *,
765 const struct resource *,
766 resource_size_t,
767 resource_size_t),
768 void *alignf_data)
769{
770 int err;
771 struct resource_constraint constraint;
772
773 if (!alignf)
774 alignf = simple_align_resource;
775
776 constraint.min = min;
777 constraint.max = max;
778 constraint.align = align;
779 constraint.alignf = alignf;
780 constraint.alignf_data = alignf_data;
781
782 if ( new->parent ) {
783 /* resource is already allocated, try reallocating with
784 the new constraints */
785 return reallocate_resource(root, new, size, &constraint);
786 }
787
788 write_lock(&resource_lock);
789 err = find_resource(root, new, size, &constraint);
790 if (err >= 0 && __request_resource(root, new))
791 err = -EBUSY;
792 write_unlock(&resource_lock);
793 return err;
794}
795
796EXPORT_SYMBOL(allocate_resource);
797
798/**
799 * lookup_resource - find an existing resource by a resource start address
800 * @root: root resource descriptor
801 * @start: resource start address
802 *
803 * Returns a pointer to the resource if found, NULL otherwise
804 */
805struct resource *lookup_resource(struct resource *root, resource_size_t start)
806{
807 struct resource *res;
808
809 read_lock(&resource_lock);
810 for (res = root->child; res; res = res->sibling) {
811 if (res->start == start)
812 break;
813 }
814 read_unlock(&resource_lock);
815
816 return res;
817}
818
819/*
820 * Insert a resource into the resource tree. If successful, return NULL,
821 * otherwise return the conflicting resource (compare to __request_resource())
822 */
823static struct resource * __insert_resource(struct resource *parent, struct resource *new)
824{
825 struct resource *first, *next;
826
827 for (;; parent = first) {
828 first = __request_resource(parent, new);
829 if (!first)
830 return first;
831
832 if (first == parent)
833 return first;
834 if (WARN_ON(first == new)) /* duplicated insertion */
835 return first;
836
837 if ((first->start > new->start) || (first->end < new->end))
838 break;
839 if ((first->start == new->start) && (first->end == new->end))
840 break;
841 }
842
843 for (next = first; ; next = next->sibling) {
844 /* Partial overlap? Bad, and unfixable */
845 if (next->start < new->start || next->end > new->end)
846 return next;
847 if (!next->sibling)
848 break;
849 if (next->sibling->start > new->end)
850 break;
851 }
852
853 new->parent = parent;
854 new->sibling = next->sibling;
855 new->child = first;
856
857 next->sibling = NULL;
858 for (next = first; next; next = next->sibling)
859 next->parent = new;
860
861 if (parent->child == first) {
862 parent->child = new;
863 } else {
864 next = parent->child;
865 while (next->sibling != first)
866 next = next->sibling;
867 next->sibling = new;
868 }
869 return NULL;
870}
871
872/**
873 * insert_resource_conflict - Inserts resource in the resource tree
874 * @parent: parent of the new resource
875 * @new: new resource to insert
876 *
877 * Returns 0 on success, conflict resource if the resource can't be inserted.
878 *
879 * This function is equivalent to request_resource_conflict when no conflict
880 * happens. If a conflict happens, and the conflicting resources
881 * entirely fit within the range of the new resource, then the new
882 * resource is inserted and the conflicting resources become children of
883 * the new resource.
884 *
885 * This function is intended for producers of resources, such as FW modules
886 * and bus drivers.
887 */
888struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
889{
890 struct resource *conflict;
891
892 write_lock(&resource_lock);
893 conflict = __insert_resource(parent, new);
894 write_unlock(&resource_lock);
895 return conflict;
896}
897
898/**
899 * insert_resource - Inserts a resource in the resource tree
900 * @parent: parent of the new resource
901 * @new: new resource to insert
902 *
903 * Returns 0 on success, -EBUSY if the resource can't be inserted.
904 *
905 * This function is intended for producers of resources, such as FW modules
906 * and bus drivers.
907 */
908int insert_resource(struct resource *parent, struct resource *new)
909{
910 struct resource *conflict;
911
912 conflict = insert_resource_conflict(parent, new);
913 return conflict ? -EBUSY : 0;
914}
915EXPORT_SYMBOL_GPL(insert_resource);
916
917/**
918 * insert_resource_expand_to_fit - Insert a resource into the resource tree
919 * @root: root resource descriptor
920 * @new: new resource to insert
921 *
922 * Insert a resource into the resource tree, possibly expanding it in order
923 * to make it encompass any conflicting resources.
924 */
925void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
926{
927 if (new->parent)
928 return;
929
930 write_lock(&resource_lock);
931 for (;;) {
932 struct resource *conflict;
933
934 conflict = __insert_resource(root, new);
935 if (!conflict)
936 break;
937 if (conflict == root)
938 break;
939
940 /* Ok, expand resource to cover the conflict, then try again .. */
941 if (conflict->start < new->start)
942 new->start = conflict->start;
943 if (conflict->end > new->end)
944 new->end = conflict->end;
945
946 pr_info("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
947 }
948 write_unlock(&resource_lock);
949}
950/*
951 * Not for general consumption, only early boot memory map parsing, PCI
952 * resource discovery, and late discovery of CXL resources are expected
953 * to use this interface. The former are built-in and only the latter,
954 * CXL, is a module.
955 */
956EXPORT_SYMBOL_NS_GPL(insert_resource_expand_to_fit, CXL);
957
958/**
959 * remove_resource - Remove a resource in the resource tree
960 * @old: resource to remove
961 *
962 * Returns 0 on success, -EINVAL if the resource is not valid.
963 *
964 * This function removes a resource previously inserted by insert_resource()
965 * or insert_resource_conflict(), and moves the children (if any) up to
966 * where they were before. insert_resource() and insert_resource_conflict()
967 * insert a new resource, and move any conflicting resources down to the
968 * children of the new resource.
969 *
970 * insert_resource(), insert_resource_conflict() and remove_resource() are
971 * intended for producers of resources, such as FW modules and bus drivers.
972 */
973int remove_resource(struct resource *old)
974{
975 int retval;
976
977 write_lock(&resource_lock);
978 retval = __release_resource(old, false);
979 write_unlock(&resource_lock);
980 return retval;
981}
982EXPORT_SYMBOL_GPL(remove_resource);
983
984static int __adjust_resource(struct resource *res, resource_size_t start,
985 resource_size_t size)
986{
987 struct resource *tmp, *parent = res->parent;
988 resource_size_t end = start + size - 1;
989 int result = -EBUSY;
990
991 if (!parent)
992 goto skip;
993
994 if ((start < parent->start) || (end > parent->end))
995 goto out;
996
997 if (res->sibling && (res->sibling->start <= end))
998 goto out;
999
1000 tmp = parent->child;
1001 if (tmp != res) {
1002 while (tmp->sibling != res)
1003 tmp = tmp->sibling;
1004 if (start <= tmp->end)
1005 goto out;
1006 }
1007
1008skip:
1009 for (tmp = res->child; tmp; tmp = tmp->sibling)
1010 if ((tmp->start < start) || (tmp->end > end))
1011 goto out;
1012
1013 res->start = start;
1014 res->end = end;
1015 result = 0;
1016
1017 out:
1018 return result;
1019}
1020
1021/**
1022 * adjust_resource - modify a resource's start and size
1023 * @res: resource to modify
1024 * @start: new start value
1025 * @size: new size
1026 *
1027 * Given an existing resource, change its start and size to match the
1028 * arguments. Returns 0 on success, -EBUSY if it can't fit.
1029 * Existing children of the resource are assumed to be immutable.
1030 */
1031int adjust_resource(struct resource *res, resource_size_t start,
1032 resource_size_t size)
1033{
1034 int result;
1035
1036 write_lock(&resource_lock);
1037 result = __adjust_resource(res, start, size);
1038 write_unlock(&resource_lock);
1039 return result;
1040}
1041EXPORT_SYMBOL(adjust_resource);
1042
1043static void __init
1044__reserve_region_with_split(struct resource *root, resource_size_t start,
1045 resource_size_t end, const char *name)
1046{
1047 struct resource *parent = root;
1048 struct resource *conflict;
1049 struct resource *res = alloc_resource(GFP_ATOMIC);
1050 struct resource *next_res = NULL;
1051 int type = resource_type(root);
1052
1053 if (!res)
1054 return;
1055
1056 res->name = name;
1057 res->start = start;
1058 res->end = end;
1059 res->flags = type | IORESOURCE_BUSY;
1060 res->desc = IORES_DESC_NONE;
1061
1062 while (1) {
1063
1064 conflict = __request_resource(parent, res);
1065 if (!conflict) {
1066 if (!next_res)
1067 break;
1068 res = next_res;
1069 next_res = NULL;
1070 continue;
1071 }
1072
1073 /* conflict covered whole area */
1074 if (conflict->start <= res->start &&
1075 conflict->end >= res->end) {
1076 free_resource(res);
1077 WARN_ON(next_res);
1078 break;
1079 }
1080
1081 /* failed, split and try again */
1082 if (conflict->start > res->start) {
1083 end = res->end;
1084 res->end = conflict->start - 1;
1085 if (conflict->end < end) {
1086 next_res = alloc_resource(GFP_ATOMIC);
1087 if (!next_res) {
1088 free_resource(res);
1089 break;
1090 }
1091 next_res->name = name;
1092 next_res->start = conflict->end + 1;
1093 next_res->end = end;
1094 next_res->flags = type | IORESOURCE_BUSY;
1095 next_res->desc = IORES_DESC_NONE;
1096 }
1097 } else {
1098 res->start = conflict->end + 1;
1099 }
1100 }
1101
1102}
1103
1104void __init
1105reserve_region_with_split(struct resource *root, resource_size_t start,
1106 resource_size_t end, const char *name)
1107{
1108 int abort = 0;
1109
1110 write_lock(&resource_lock);
1111 if (root->start > start || root->end < end) {
1112 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
1113 (unsigned long long)start, (unsigned long long)end,
1114 root);
1115 if (start > root->end || end < root->start)
1116 abort = 1;
1117 else {
1118 if (end > root->end)
1119 end = root->end;
1120 if (start < root->start)
1121 start = root->start;
1122 pr_err("fixing request to [0x%llx-0x%llx]\n",
1123 (unsigned long long)start,
1124 (unsigned long long)end);
1125 }
1126 dump_stack();
1127 }
1128 if (!abort)
1129 __reserve_region_with_split(root, start, end, name);
1130 write_unlock(&resource_lock);
1131}
1132
1133/**
1134 * resource_alignment - calculate resource's alignment
1135 * @res: resource pointer
1136 *
1137 * Returns alignment on success, 0 (invalid alignment) on failure.
1138 */
1139resource_size_t resource_alignment(struct resource *res)
1140{
1141 switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
1142 case IORESOURCE_SIZEALIGN:
1143 return resource_size(res);
1144 case IORESOURCE_STARTALIGN:
1145 return res->start;
1146 default:
1147 return 0;
1148 }
1149}
1150
1151/*
1152 * This is compatibility stuff for IO resources.
1153 *
1154 * Note how this, unlike the above, knows about
1155 * the IO flag meanings (busy etc).
1156 *
1157 * request_region creates a new busy region.
1158 *
1159 * release_region releases a matching busy region.
1160 */
1161
1162static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1163
1164static struct inode *iomem_inode;
1165
1166#ifdef CONFIG_IO_STRICT_DEVMEM
1167static void revoke_iomem(struct resource *res)
1168{
1169 /* pairs with smp_store_release() in iomem_init_inode() */
1170 struct inode *inode = smp_load_acquire(&iomem_inode);
1171
1172 /*
1173 * Check that the initialization has completed. Losing the race
1174 * is ok because it means drivers are claiming resources before
1175 * the fs_initcall level of init and prevent iomem_get_mapping users
1176 * from establishing mappings.
1177 */
1178 if (!inode)
1179 return;
1180
1181 /*
1182 * The expectation is that the driver has successfully marked
1183 * the resource busy by this point, so devmem_is_allowed()
1184 * should start returning false, however for performance this
1185 * does not iterate the entire resource range.
1186 */
1187 if (devmem_is_allowed(PHYS_PFN(res->start)) &&
1188 devmem_is_allowed(PHYS_PFN(res->end))) {
1189 /*
1190 * *cringe* iomem=relaxed says "go ahead, what's the
1191 * worst that can happen?"
1192 */
1193 return;
1194 }
1195
1196 unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
1197}
1198#else
1199static void revoke_iomem(struct resource *res) {}
1200#endif
1201
1202struct address_space *iomem_get_mapping(void)
1203{
1204 /*
1205 * This function is only called from file open paths, hence guaranteed
1206 * that fs_initcalls have completed and no need to check for NULL. But
1207 * since revoke_iomem can be called before the initcall we still need
1208 * the barrier to appease checkers.
1209 */
1210 return smp_load_acquire(&iomem_inode)->i_mapping;
1211}
1212
1213static int __request_region_locked(struct resource *res, struct resource *parent,
1214 resource_size_t start, resource_size_t n,
1215 const char *name, int flags)
1216{
1217 DECLARE_WAITQUEUE(wait, current);
1218
1219 res->name = name;
1220 res->start = start;
1221 res->end = start + n - 1;
1222
1223 for (;;) {
1224 struct resource *conflict;
1225
1226 res->flags = resource_type(parent) | resource_ext_type(parent);
1227 res->flags |= IORESOURCE_BUSY | flags;
1228 res->desc = parent->desc;
1229
1230 conflict = __request_resource(parent, res);
1231 if (!conflict)
1232 break;
1233 /*
1234 * mm/hmm.c reserves physical addresses which then
1235 * become unavailable to other users. Conflicts are
1236 * not expected. Warn to aid debugging if encountered.
1237 */
1238 if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
1239 pr_warn("Unaddressable device %s %pR conflicts with %pR",
1240 conflict->name, conflict, res);
1241 }
1242 if (conflict != parent) {
1243 if (!(conflict->flags & IORESOURCE_BUSY)) {
1244 parent = conflict;
1245 continue;
1246 }
1247 }
1248 if (conflict->flags & flags & IORESOURCE_MUXED) {
1249 add_wait_queue(&muxed_resource_wait, &wait);
1250 write_unlock(&resource_lock);
1251 set_current_state(TASK_UNINTERRUPTIBLE);
1252 schedule();
1253 remove_wait_queue(&muxed_resource_wait, &wait);
1254 write_lock(&resource_lock);
1255 continue;
1256 }
1257 /* Uhhuh, that didn't work out.. */
1258 return -EBUSY;
1259 }
1260
1261 return 0;
1262}
1263
1264/**
1265 * __request_region - create a new busy resource region
1266 * @parent: parent resource descriptor
1267 * @start: resource start address
1268 * @n: resource region size
1269 * @name: reserving caller's ID string
1270 * @flags: IO resource flags
1271 */
1272struct resource *__request_region(struct resource *parent,
1273 resource_size_t start, resource_size_t n,
1274 const char *name, int flags)
1275{
1276 struct resource *res = alloc_resource(GFP_KERNEL);
1277 int ret;
1278
1279 if (!res)
1280 return NULL;
1281
1282 write_lock(&resource_lock);
1283 ret = __request_region_locked(res, parent, start, n, name, flags);
1284 write_unlock(&resource_lock);
1285
1286 if (ret) {
1287 free_resource(res);
1288 return NULL;
1289 }
1290
1291 if (parent == &iomem_resource)
1292 revoke_iomem(res);
1293
1294 return res;
1295}
1296EXPORT_SYMBOL(__request_region);
1297
1298/**
1299 * __release_region - release a previously reserved resource region
1300 * @parent: parent resource descriptor
1301 * @start: resource start address
1302 * @n: resource region size
1303 *
1304 * The described resource region must match a currently busy region.
1305 */
1306void __release_region(struct resource *parent, resource_size_t start,
1307 resource_size_t n)
1308{
1309 struct resource **p;
1310 resource_size_t end;
1311
1312 p = &parent->child;
1313 end = start + n - 1;
1314
1315 write_lock(&resource_lock);
1316
1317 for (;;) {
1318 struct resource *res = *p;
1319
1320 if (!res)
1321 break;
1322 if (res->start <= start && res->end >= end) {
1323 if (!(res->flags & IORESOURCE_BUSY)) {
1324 p = &res->child;
1325 continue;
1326 }
1327 if (res->start != start || res->end != end)
1328 break;
1329 *p = res->sibling;
1330 write_unlock(&resource_lock);
1331 if (res->flags & IORESOURCE_MUXED)
1332 wake_up(&muxed_resource_wait);
1333 free_resource(res);
1334 return;
1335 }
1336 p = &res->sibling;
1337 }
1338
1339 write_unlock(&resource_lock);
1340
1341 pr_warn("Trying to free nonexistent resource <%pa-%pa>\n", &start, &end);
1342}
1343EXPORT_SYMBOL(__release_region);
1344
1345#ifdef CONFIG_MEMORY_HOTREMOVE
1346/**
1347 * release_mem_region_adjustable - release a previously reserved memory region
1348 * @start: resource start address
1349 * @size: resource region size
1350 *
1351 * This interface is intended for memory hot-delete. The requested region
1352 * is released from a currently busy memory resource. The requested region
1353 * must either match exactly or fit into a single busy resource entry. In
1354 * the latter case, the remaining resource is adjusted accordingly.
1355 * Existing children of the busy memory resource must be immutable in the
1356 * request.
1357 *
1358 * Note:
1359 * - Additional release conditions, such as overlapping region, can be
1360 * supported after they are confirmed as valid cases.
1361 * - When a busy memory resource gets split into two entries, the code
1362 * assumes that all children remain in the lower address entry for
1363 * simplicity. Enhance this logic when necessary.
1364 */
1365void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
1366{
1367 struct resource *parent = &iomem_resource;
1368 struct resource *new_res = NULL;
1369 bool alloc_nofail = false;
1370 struct resource **p;
1371 struct resource *res;
1372 resource_size_t end;
1373
1374 end = start + size - 1;
1375 if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
1376 return;
1377
1378 /*
1379 * We free up quite a lot of memory on memory hotunplug (esp., memap),
1380 * just before releasing the region. This is highly unlikely to
1381 * fail - let's play save and make it never fail as the caller cannot
1382 * perform any error handling (e.g., trying to re-add memory will fail
1383 * similarly).
1384 */
1385retry:
1386 new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
1387
1388 p = &parent->child;
1389 write_lock(&resource_lock);
1390
1391 while ((res = *p)) {
1392 if (res->start >= end)
1393 break;
1394
1395 /* look for the next resource if it does not fit into */
1396 if (res->start > start || res->end < end) {
1397 p = &res->sibling;
1398 continue;
1399 }
1400
1401 if (!(res->flags & IORESOURCE_MEM))
1402 break;
1403
1404 if (!(res->flags & IORESOURCE_BUSY)) {
1405 p = &res->child;
1406 continue;
1407 }
1408
1409 /* found the target resource; let's adjust accordingly */
1410 if (res->start == start && res->end == end) {
1411 /* free the whole entry */
1412 *p = res->sibling;
1413 free_resource(res);
1414 } else if (res->start == start && res->end != end) {
1415 /* adjust the start */
1416 WARN_ON_ONCE(__adjust_resource(res, end + 1,
1417 res->end - end));
1418 } else if (res->start != start && res->end == end) {
1419 /* adjust the end */
1420 WARN_ON_ONCE(__adjust_resource(res, res->start,
1421 start - res->start));
1422 } else {
1423 /* split into two entries - we need a new resource */
1424 if (!new_res) {
1425 new_res = alloc_resource(GFP_ATOMIC);
1426 if (!new_res) {
1427 alloc_nofail = true;
1428 write_unlock(&resource_lock);
1429 goto retry;
1430 }
1431 }
1432 new_res->name = res->name;
1433 new_res->start = end + 1;
1434 new_res->end = res->end;
1435 new_res->flags = res->flags;
1436 new_res->desc = res->desc;
1437 new_res->parent = res->parent;
1438 new_res->sibling = res->sibling;
1439 new_res->child = NULL;
1440
1441 if (WARN_ON_ONCE(__adjust_resource(res, res->start,
1442 start - res->start)))
1443 break;
1444 res->sibling = new_res;
1445 new_res = NULL;
1446 }
1447
1448 break;
1449 }
1450
1451 write_unlock(&resource_lock);
1452 free_resource(new_res);
1453}
1454#endif /* CONFIG_MEMORY_HOTREMOVE */
1455
1456#ifdef CONFIG_MEMORY_HOTPLUG
1457static bool system_ram_resources_mergeable(struct resource *r1,
1458 struct resource *r2)
1459{
1460 /* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
1461 return r1->flags == r2->flags && r1->end + 1 == r2->start &&
1462 r1->name == r2->name && r1->desc == r2->desc &&
1463 !r1->child && !r2->child;
1464}
1465
1466/**
1467 * merge_system_ram_resource - mark the System RAM resource mergeable and try to
1468 * merge it with adjacent, mergeable resources
1469 * @res: resource descriptor
1470 *
1471 * This interface is intended for memory hotplug, whereby lots of contiguous
1472 * system ram resources are added (e.g., via add_memory*()) by a driver, and
1473 * the actual resource boundaries are not of interest (e.g., it might be
1474 * relevant for DIMMs). Only resources that are marked mergeable, that have the
1475 * same parent, and that don't have any children are considered. All mergeable
1476 * resources must be immutable during the request.
1477 *
1478 * Note:
1479 * - The caller has to make sure that no pointers to resources that are
1480 * marked mergeable are used anymore after this call - the resource might
1481 * be freed and the pointer might be stale!
1482 * - release_mem_region_adjustable() will split on demand on memory hotunplug
1483 */
1484void merge_system_ram_resource(struct resource *res)
1485{
1486 const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
1487 struct resource *cur;
1488
1489 if (WARN_ON_ONCE((res->flags & flags) != flags))
1490 return;
1491
1492 write_lock(&resource_lock);
1493 res->flags |= IORESOURCE_SYSRAM_MERGEABLE;
1494
1495 /* Try to merge with next item in the list. */
1496 cur = res->sibling;
1497 if (cur && system_ram_resources_mergeable(res, cur)) {
1498 res->end = cur->end;
1499 res->sibling = cur->sibling;
1500 free_resource(cur);
1501 }
1502
1503 /* Try to merge with previous item in the list. */
1504 cur = res->parent->child;
1505 while (cur && cur->sibling != res)
1506 cur = cur->sibling;
1507 if (cur && system_ram_resources_mergeable(cur, res)) {
1508 cur->end = res->end;
1509 cur->sibling = res->sibling;
1510 free_resource(res);
1511 }
1512 write_unlock(&resource_lock);
1513}
1514#endif /* CONFIG_MEMORY_HOTPLUG */
1515
1516/*
1517 * Managed region resource
1518 */
1519static void devm_resource_release(struct device *dev, void *ptr)
1520{
1521 struct resource **r = ptr;
1522
1523 release_resource(*r);
1524}
1525
1526/**
1527 * devm_request_resource() - request and reserve an I/O or memory resource
1528 * @dev: device for which to request the resource
1529 * @root: root of the resource tree from which to request the resource
1530 * @new: descriptor of the resource to request
1531 *
1532 * This is a device-managed version of request_resource(). There is usually
1533 * no need to release resources requested by this function explicitly since
1534 * that will be taken care of when the device is unbound from its driver.
1535 * If for some reason the resource needs to be released explicitly, because
1536 * of ordering issues for example, drivers must call devm_release_resource()
1537 * rather than the regular release_resource().
1538 *
1539 * When a conflict is detected between any existing resources and the newly
1540 * requested resource, an error message will be printed.
1541 *
1542 * Returns 0 on success or a negative error code on failure.
1543 */
1544int devm_request_resource(struct device *dev, struct resource *root,
1545 struct resource *new)
1546{
1547 struct resource *conflict, **ptr;
1548
1549 ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
1550 if (!ptr)
1551 return -ENOMEM;
1552
1553 *ptr = new;
1554
1555 conflict = request_resource_conflict(root, new);
1556 if (conflict) {
1557 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
1558 new, conflict->name, conflict);
1559 devres_free(ptr);
1560 return -EBUSY;
1561 }
1562
1563 devres_add(dev, ptr);
1564 return 0;
1565}
1566EXPORT_SYMBOL(devm_request_resource);
1567
1568static int devm_resource_match(struct device *dev, void *res, void *data)
1569{
1570 struct resource **ptr = res;
1571
1572 return *ptr == data;
1573}
1574
1575/**
1576 * devm_release_resource() - release a previously requested resource
1577 * @dev: device for which to release the resource
1578 * @new: descriptor of the resource to release
1579 *
1580 * Releases a resource previously requested using devm_request_resource().
1581 */
1582void devm_release_resource(struct device *dev, struct resource *new)
1583{
1584 WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
1585 new));
1586}
1587EXPORT_SYMBOL(devm_release_resource);
1588
1589struct region_devres {
1590 struct resource *parent;
1591 resource_size_t start;
1592 resource_size_t n;
1593};
1594
1595static void devm_region_release(struct device *dev, void *res)
1596{
1597 struct region_devres *this = res;
1598
1599 __release_region(this->parent, this->start, this->n);
1600}
1601
1602static int devm_region_match(struct device *dev, void *res, void *match_data)
1603{
1604 struct region_devres *this = res, *match = match_data;
1605
1606 return this->parent == match->parent &&
1607 this->start == match->start && this->n == match->n;
1608}
1609
1610struct resource *
1611__devm_request_region(struct device *dev, struct resource *parent,
1612 resource_size_t start, resource_size_t n, const char *name)
1613{
1614 struct region_devres *dr = NULL;
1615 struct resource *res;
1616
1617 dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1618 GFP_KERNEL);
1619 if (!dr)
1620 return NULL;
1621
1622 dr->parent = parent;
1623 dr->start = start;
1624 dr->n = n;
1625
1626 res = __request_region(parent, start, n, name, 0);
1627 if (res)
1628 devres_add(dev, dr);
1629 else
1630 devres_free(dr);
1631
1632 return res;
1633}
1634EXPORT_SYMBOL(__devm_request_region);
1635
1636void __devm_release_region(struct device *dev, struct resource *parent,
1637 resource_size_t start, resource_size_t n)
1638{
1639 struct region_devres match_data = { parent, start, n };
1640
1641 __release_region(parent, start, n);
1642 WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1643 &match_data));
1644}
1645EXPORT_SYMBOL(__devm_release_region);
1646
1647/*
1648 * Reserve I/O ports or memory based on "reserve=" kernel parameter.
1649 */
1650#define MAXRESERVE 4
1651static int __init reserve_setup(char *str)
1652{
1653 static int reserved;
1654 static struct resource reserve[MAXRESERVE];
1655
1656 for (;;) {
1657 unsigned int io_start, io_num;
1658 int x = reserved;
1659 struct resource *parent;
1660
1661 if (get_option(&str, &io_start) != 2)
1662 break;
1663 if (get_option(&str, &io_num) == 0)
1664 break;
1665 if (x < MAXRESERVE) {
1666 struct resource *res = reserve + x;
1667
1668 /*
1669 * If the region starts below 0x10000, we assume it's
1670 * I/O port space; otherwise assume it's memory.
1671 */
1672 if (io_start < 0x10000) {
1673 res->flags = IORESOURCE_IO;
1674 parent = &ioport_resource;
1675 } else {
1676 res->flags = IORESOURCE_MEM;
1677 parent = &iomem_resource;
1678 }
1679 res->name = "reserved";
1680 res->start = io_start;
1681 res->end = io_start + io_num - 1;
1682 res->flags |= IORESOURCE_BUSY;
1683 res->desc = IORES_DESC_NONE;
1684 res->child = NULL;
1685 if (request_resource(parent, res) == 0)
1686 reserved = x+1;
1687 }
1688 }
1689 return 1;
1690}
1691__setup("reserve=", reserve_setup);
1692
1693/*
1694 * Check if the requested addr and size spans more than any slot in the
1695 * iomem resource tree.
1696 */
1697int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1698{
1699 resource_size_t end = addr + size - 1;
1700 struct resource *p;
1701 int err = 0;
1702
1703 read_lock(&resource_lock);
1704 for_each_resource(&iomem_resource, p, false) {
1705 /*
1706 * We can probably skip the resources without
1707 * IORESOURCE_IO attribute?
1708 */
1709 if (p->start > end)
1710 continue;
1711 if (p->end < addr)
1712 continue;
1713 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1714 PFN_DOWN(p->end) >= PFN_DOWN(end))
1715 continue;
1716 /*
1717 * if a resource is "BUSY", it's not a hardware resource
1718 * but a driver mapping of such a resource; we don't want
1719 * to warn for those; some drivers legitimately map only
1720 * partial hardware resources. (example: vesafb)
1721 */
1722 if (p->flags & IORESOURCE_BUSY)
1723 continue;
1724
1725 pr_warn("resource sanity check: requesting [mem %pa-%pa], which spans more than %s %pR\n",
1726 &addr, &end, p->name, p);
1727 err = -1;
1728 break;
1729 }
1730 read_unlock(&resource_lock);
1731
1732 return err;
1733}
1734
1735#ifdef CONFIG_STRICT_DEVMEM
1736static int strict_iomem_checks = 1;
1737#else
1738static int strict_iomem_checks;
1739#endif
1740
1741/*
1742 * Check if an address is exclusive to the kernel and must not be mapped to
1743 * user space, for example, via /dev/mem.
1744 *
1745 * Returns true if exclusive to the kernel, otherwise returns false.
1746 */
1747bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size)
1748{
1749 const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
1750 IORESOURCE_EXCLUSIVE;
1751 bool skip_children = false, err = false;
1752 struct resource *p;
1753
1754 read_lock(&resource_lock);
1755 for_each_resource(root, p, skip_children) {
1756 if (p->start >= addr + size)
1757 break;
1758 if (p->end < addr) {
1759 skip_children = true;
1760 continue;
1761 }
1762 skip_children = false;
1763
1764 /*
1765 * IORESOURCE_SYSTEM_RAM resources are exclusive if
1766 * IORESOURCE_EXCLUSIVE is set, even if they
1767 * are not busy and even if "iomem=relaxed" is set. The
1768 * responsible driver dynamically adds/removes system RAM within
1769 * such an area and uncontrolled access is dangerous.
1770 */
1771 if ((p->flags & exclusive_system_ram) == exclusive_system_ram) {
1772 err = true;
1773 break;
1774 }
1775
1776 /*
1777 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
1778 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
1779 * resource is busy.
1780 */
1781 if (!strict_iomem_checks || !(p->flags & IORESOURCE_BUSY))
1782 continue;
1783 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
1784 || p->flags & IORESOURCE_EXCLUSIVE) {
1785 err = true;
1786 break;
1787 }
1788 }
1789 read_unlock(&resource_lock);
1790
1791 return err;
1792}
1793
1794bool iomem_is_exclusive(u64 addr)
1795{
1796 return resource_is_exclusive(&iomem_resource, addr & PAGE_MASK,
1797 PAGE_SIZE);
1798}
1799
1800struct resource_entry *resource_list_create_entry(struct resource *res,
1801 size_t extra_size)
1802{
1803 struct resource_entry *entry;
1804
1805 entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
1806 if (entry) {
1807 INIT_LIST_HEAD(&entry->node);
1808 entry->res = res ? res : &entry->__res;
1809 }
1810
1811 return entry;
1812}
1813EXPORT_SYMBOL(resource_list_create_entry);
1814
1815void resource_list_free(struct list_head *head)
1816{
1817 struct resource_entry *entry, *tmp;
1818
1819 list_for_each_entry_safe(entry, tmp, head, node)
1820 resource_list_destroy_entry(entry);
1821}
1822EXPORT_SYMBOL(resource_list_free);
1823
1824#ifdef CONFIG_GET_FREE_REGION
1825#define GFR_DESCENDING (1UL << 0)
1826#define GFR_REQUEST_REGION (1UL << 1)
1827#define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
1828
1829static resource_size_t gfr_start(struct resource *base, resource_size_t size,
1830 resource_size_t align, unsigned long flags)
1831{
1832 if (flags & GFR_DESCENDING) {
1833 resource_size_t end;
1834
1835 end = min_t(resource_size_t, base->end,
1836 (1ULL << MAX_PHYSMEM_BITS) - 1);
1837 return end - size + 1;
1838 }
1839
1840 return ALIGN(base->start, align);
1841}
1842
1843static bool gfr_continue(struct resource *base, resource_size_t addr,
1844 resource_size_t size, unsigned long flags)
1845{
1846 if (flags & GFR_DESCENDING)
1847 return addr > size && addr >= base->start;
1848 /*
1849 * In the ascend case be careful that the last increment by
1850 * @size did not wrap 0.
1851 */
1852 return addr > addr - size &&
1853 addr <= min_t(resource_size_t, base->end,
1854 (1ULL << MAX_PHYSMEM_BITS) - 1);
1855}
1856
1857static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
1858 unsigned long flags)
1859{
1860 if (flags & GFR_DESCENDING)
1861 return addr - size;
1862 return addr + size;
1863}
1864
1865static void remove_free_mem_region(void *_res)
1866{
1867 struct resource *res = _res;
1868
1869 if (res->parent)
1870 remove_resource(res);
1871 free_resource(res);
1872}
1873
1874static struct resource *
1875get_free_mem_region(struct device *dev, struct resource *base,
1876 resource_size_t size, const unsigned long align,
1877 const char *name, const unsigned long desc,
1878 const unsigned long flags)
1879{
1880 resource_size_t addr;
1881 struct resource *res;
1882 struct region_devres *dr = NULL;
1883
1884 size = ALIGN(size, align);
1885
1886 res = alloc_resource(GFP_KERNEL);
1887 if (!res)
1888 return ERR_PTR(-ENOMEM);
1889
1890 if (dev && (flags & GFR_REQUEST_REGION)) {
1891 dr = devres_alloc(devm_region_release,
1892 sizeof(struct region_devres), GFP_KERNEL);
1893 if (!dr) {
1894 free_resource(res);
1895 return ERR_PTR(-ENOMEM);
1896 }
1897 } else if (dev) {
1898 if (devm_add_action_or_reset(dev, remove_free_mem_region, res))
1899 return ERR_PTR(-ENOMEM);
1900 }
1901
1902 write_lock(&resource_lock);
1903 for (addr = gfr_start(base, size, align, flags);
1904 gfr_continue(base, addr, align, flags);
1905 addr = gfr_next(addr, align, flags)) {
1906 if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
1907 REGION_DISJOINT)
1908 continue;
1909
1910 if (flags & GFR_REQUEST_REGION) {
1911 if (__request_region_locked(res, &iomem_resource, addr,
1912 size, name, 0))
1913 break;
1914
1915 if (dev) {
1916 dr->parent = &iomem_resource;
1917 dr->start = addr;
1918 dr->n = size;
1919 devres_add(dev, dr);
1920 }
1921
1922 res->desc = desc;
1923 write_unlock(&resource_lock);
1924
1925
1926 /*
1927 * A driver is claiming this region so revoke any
1928 * mappings.
1929 */
1930 revoke_iomem(res);
1931 } else {
1932 res->start = addr;
1933 res->end = addr + size - 1;
1934 res->name = name;
1935 res->desc = desc;
1936 res->flags = IORESOURCE_MEM;
1937
1938 /*
1939 * Only succeed if the resource hosts an exclusive
1940 * range after the insert
1941 */
1942 if (__insert_resource(base, res) || res->child)
1943 break;
1944
1945 write_unlock(&resource_lock);
1946 }
1947
1948 return res;
1949 }
1950 write_unlock(&resource_lock);
1951
1952 if (flags & GFR_REQUEST_REGION) {
1953 free_resource(res);
1954 devres_free(dr);
1955 } else if (dev)
1956 devm_release_action(dev, remove_free_mem_region, res);
1957
1958 return ERR_PTR(-ERANGE);
1959}
1960
1961/**
1962 * devm_request_free_mem_region - find free region for device private memory
1963 *
1964 * @dev: device struct to bind the resource to
1965 * @size: size in bytes of the device memory to add
1966 * @base: resource tree to look in
1967 *
1968 * This function tries to find an empty range of physical address big enough to
1969 * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
1970 * memory, which in turn allocates struct pages.
1971 */
1972struct resource *devm_request_free_mem_region(struct device *dev,
1973 struct resource *base, unsigned long size)
1974{
1975 unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
1976
1977 return get_free_mem_region(dev, base, size, GFR_DEFAULT_ALIGN,
1978 dev_name(dev),
1979 IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
1980}
1981EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
1982
1983struct resource *request_free_mem_region(struct resource *base,
1984 unsigned long size, const char *name)
1985{
1986 unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
1987
1988 return get_free_mem_region(NULL, base, size, GFR_DEFAULT_ALIGN, name,
1989 IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
1990}
1991EXPORT_SYMBOL_GPL(request_free_mem_region);
1992
1993/**
1994 * alloc_free_mem_region - find a free region relative to @base
1995 * @base: resource that will parent the new resource
1996 * @size: size in bytes of memory to allocate from @base
1997 * @align: alignment requirements for the allocation
1998 * @name: resource name
1999 *
2000 * Buses like CXL, that can dynamically instantiate new memory regions,
2001 * need a method to allocate physical address space for those regions.
2002 * Allocate and insert a new resource to cover a free, unclaimed by a
2003 * descendant of @base, range in the span of @base.
2004 */
2005struct resource *alloc_free_mem_region(struct resource *base,
2006 unsigned long size, unsigned long align,
2007 const char *name)
2008{
2009 /* Default of ascending direction and insert resource */
2010 unsigned long flags = 0;
2011
2012 return get_free_mem_region(NULL, base, size, align, name,
2013 IORES_DESC_NONE, flags);
2014}
2015EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
2016#endif /* CONFIG_GET_FREE_REGION */
2017
2018static int __init strict_iomem(char *str)
2019{
2020 if (strstr(str, "relaxed"))
2021 strict_iomem_checks = 0;
2022 if (strstr(str, "strict"))
2023 strict_iomem_checks = 1;
2024 return 1;
2025}
2026
2027static int iomem_fs_init_fs_context(struct fs_context *fc)
2028{
2029 return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
2030}
2031
2032static struct file_system_type iomem_fs_type = {
2033 .name = "iomem",
2034 .owner = THIS_MODULE,
2035 .init_fs_context = iomem_fs_init_fs_context,
2036 .kill_sb = kill_anon_super,
2037};
2038
2039static int __init iomem_init_inode(void)
2040{
2041 static struct vfsmount *iomem_vfs_mount;
2042 static int iomem_fs_cnt;
2043 struct inode *inode;
2044 int rc;
2045
2046 rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt);
2047 if (rc < 0) {
2048 pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc);
2049 return rc;
2050 }
2051
2052 inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb);
2053 if (IS_ERR(inode)) {
2054 rc = PTR_ERR(inode);
2055 pr_err("Cannot allocate inode for iomem: %d\n", rc);
2056 simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt);
2057 return rc;
2058 }
2059
2060 /*
2061 * Publish iomem revocation inode initialized.
2062 * Pairs with smp_load_acquire() in revoke_iomem().
2063 */
2064 smp_store_release(&iomem_inode, inode);
2065
2066 return 0;
2067}
2068
2069fs_initcall(iomem_init_inode);
2070
2071__setup("iomem=", strict_iomem);