projects/linux·blob v6.0-rc6 · refs

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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 <[email protected]>
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 <asm/io.h>
31
32
33struct resource ioport_resource = {
34 .name = "PCI IO",
35 .start = 0,
36 .end = IO_SPACE_LIMIT,
37 .flags = IORESOURCE_IO,
38};
39EXPORT_SYMBOL(ioport_resource);
40
41struct resource iomem_resource = {
42 .name = "PCI mem",
43 .start = 0,
44 .end = -1,
45 .flags = IORESOURCE_MEM,
46};
47EXPORT_SYMBOL(iomem_resource);
48
49/* constraints to be met while allocating resources */
50struct resource_constraint {
51 resource_size_t min, max, align;
52 resource_size_t (*alignf)(void *, const struct resource *,
53 resource_size_t, resource_size_t);
54 void *alignf_data;
55};
56
57static DEFINE_RWLOCK(resource_lock);
58
59static struct resource *next_resource(struct resource *p)
60{
61 if (p->child)
62 return p->child;
63 while (!p->sibling && p->parent)
64 p = p->parent;
65 return p->sibling;
66}
67
68static struct resource *next_resource_skip_children(struct resource *p)
69{
70 while (!p->sibling && p->parent)
71 p = p->parent;
72 return p->sibling;
73}
74
75#define for_each_resource(_root, _p, _skip_children) \
76 for ((_p) = (_root)->child; (_p); \
77 (_p) = (_skip_children) ? next_resource_skip_children(_p) : \
78 next_resource(_p))
79
80static void *r_next(struct seq_file *m, void *v, loff_t *pos)
81{
82 struct resource *p = v;
83 (*pos)++;
84 return (void *)next_resource(p);
85}
86
87#ifdef CONFIG_PROC_FS
88
89enum { MAX_IORES_LEVEL = 5 };
90
91static void *r_start(struct seq_file *m, loff_t *pos)
92 __acquires(resource_lock)
93{
94 struct resource *p = pde_data(file_inode(m->file));
95 loff_t l = 0;
96 read_lock(&resource_lock);
97 for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
98 ;
99 return p;
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 (p = iomem_resource.child; p; p = next_resource(p)) {
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 calls the @func callback against all memory ranges, which
436 * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
437 */
438int walk_mem_res(u64 start, u64 end, void *arg,
439 int (*func)(struct resource *, void *))
440{
441 unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
442
443 return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, arg,
444 func);
445}
446
447/*
448 * This function calls the @func callback against all memory ranges of type
449 * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
450 * It is to be used only for System RAM.
451 */
452int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
453 void *arg, int (*func)(unsigned long, unsigned long, void *))
454{
455 resource_size_t start, end;
456 unsigned long flags;
457 struct resource res;
458 unsigned long pfn, end_pfn;
459 int ret = -EINVAL;
460
461 start = (u64) start_pfn << PAGE_SHIFT;
462 end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
463 flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
464 while (start < end &&
465 !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
466 pfn = PFN_UP(res.start);
467 end_pfn = PFN_DOWN(res.end + 1);
468 if (end_pfn > pfn)
469 ret = (*func)(pfn, end_pfn - pfn, arg);
470 if (ret)
471 break;
472 start = res.end + 1;
473 }
474 return ret;
475}
476
477static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
478{
479 return 1;
480}
481
482/*
483 * This generic page_is_ram() returns true if specified address is
484 * registered as System RAM in iomem_resource list.
485 */
486int __weak page_is_ram(unsigned long pfn)
487{
488 return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
489}
490EXPORT_SYMBOL_GPL(page_is_ram);
491
492static int __region_intersects(struct resource *parent, resource_size_t start,
493 size_t size, unsigned long flags,
494 unsigned long desc)
495{
496 struct resource res;
497 int type = 0; int other = 0;
498 struct resource *p;
499
500 res.start = start;
501 res.end = start + size - 1;
502
503 for (p = parent->child; p ; p = p->sibling) {
504 bool is_type = (((p->flags & flags) == flags) &&
505 ((desc == IORES_DESC_NONE) ||
506 (desc == p->desc)));
507
508 if (resource_overlaps(p, &res))
509 is_type ? type++ : other++;
510 }
511
512 if (type == 0)
513 return REGION_DISJOINT;
514
515 if (other == 0)
516 return REGION_INTERSECTS;
517
518 return REGION_MIXED;
519}
520
521/**
522 * region_intersects() - determine intersection of region with known resources
523 * @start: region start address
524 * @size: size of region
525 * @flags: flags of resource (in iomem_resource)
526 * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
527 *
528 * Check if the specified region partially overlaps or fully eclipses a
529 * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
530 * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
531 * return REGION_MIXED if the region overlaps @flags/@desc and another
532 * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
533 * and no other defined resource. Note that REGION_INTERSECTS is also
534 * returned in the case when the specified region overlaps RAM and undefined
535 * memory holes.
536 *
537 * region_intersect() is used by memory remapping functions to ensure
538 * the user is not remapping RAM and is a vast speed up over walking
539 * through the resource table page by page.
540 */
541int region_intersects(resource_size_t start, size_t size, unsigned long flags,
542 unsigned long desc)
543{
544 int ret;
545
546 read_lock(&resource_lock);
547 ret = __region_intersects(&iomem_resource, start, size, flags, desc);
548 read_unlock(&resource_lock);
549
550 return ret;
551}
552EXPORT_SYMBOL_GPL(region_intersects);
553
554void __weak arch_remove_reservations(struct resource *avail)
555{
556}
557
558static resource_size_t simple_align_resource(void *data,
559 const struct resource *avail,
560 resource_size_t size,
561 resource_size_t align)
562{
563 return avail->start;
564}
565
566static void resource_clip(struct resource *res, resource_size_t min,
567 resource_size_t max)
568{
569 if (res->start < min)
570 res->start = min;
571 if (res->end > max)
572 res->end = max;
573}
574
575/*
576 * Find empty slot in the resource tree with the given range and
577 * alignment constraints
578 */
579static int __find_resource(struct resource *root, struct resource *old,
580 struct resource *new,
581 resource_size_t size,
582 struct resource_constraint *constraint)
583{
584 struct resource *this = root->child;
585 struct resource tmp = *new, avail, alloc;
586
587 tmp.start = root->start;
588 /*
589 * Skip past an allocated resource that starts at 0, since the assignment
590 * of this->start - 1 to tmp->end below would cause an underflow.
591 */
592 if (this && this->start == root->start) {
593 tmp.start = (this == old) ? old->start : this->end + 1;
594 this = this->sibling;
595 }
596 for(;;) {
597 if (this)
598 tmp.end = (this == old) ? this->end : this->start - 1;
599 else
600 tmp.end = root->end;
601
602 if (tmp.end < tmp.start)
603 goto next;
604
605 resource_clip(&tmp, constraint->min, constraint->max);
606 arch_remove_reservations(&tmp);
607
608 /* Check for overflow after ALIGN() */
609 avail.start = ALIGN(tmp.start, constraint->align);
610 avail.end = tmp.end;
611 avail.flags = new->flags & ~IORESOURCE_UNSET;
612 if (avail.start >= tmp.start) {
613 alloc.flags = avail.flags;
614 alloc.start = constraint->alignf(constraint->alignf_data, &avail,
615 size, constraint->align);
616 alloc.end = alloc.start + size - 1;
617 if (alloc.start <= alloc.end &&
618 resource_contains(&avail, &alloc)) {
619 new->start = alloc.start;
620 new->end = alloc.end;
621 return 0;
622 }
623 }
624
625next: if (!this || this->end == root->end)
626 break;
627
628 if (this != old)
629 tmp.start = this->end + 1;
630 this = this->sibling;
631 }
632 return -EBUSY;
633}
634
635/*
636 * Find empty slot in the resource tree given range and alignment.
637 */
638static int find_resource(struct resource *root, struct resource *new,
639 resource_size_t size,
640 struct resource_constraint *constraint)
641{
642 return __find_resource(root, NULL, new, size, constraint);
643}
644
645/**
646 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
647 * The resource will be relocated if the new size cannot be reallocated in the
648 * current location.
649 *
650 * @root: root resource descriptor
651 * @old: resource descriptor desired by caller
652 * @newsize: new size of the resource descriptor
653 * @constraint: the size and alignment constraints to be met.
654 */
655static int reallocate_resource(struct resource *root, struct resource *old,
656 resource_size_t newsize,
657 struct resource_constraint *constraint)
658{
659 int err=0;
660 struct resource new = *old;
661 struct resource *conflict;
662
663 write_lock(&resource_lock);
664
665 if ((err = __find_resource(root, old, &new, newsize, constraint)))
666 goto out;
667
668 if (resource_contains(&new, old)) {
669 old->start = new.start;
670 old->end = new.end;
671 goto out;
672 }
673
674 if (old->child) {
675 err = -EBUSY;
676 goto out;
677 }
678
679 if (resource_contains(old, &new)) {
680 old->start = new.start;
681 old->end = new.end;
682 } else {
683 __release_resource(old, true);
684 *old = new;
685 conflict = __request_resource(root, old);
686 BUG_ON(conflict);
687 }
688out:
689 write_unlock(&resource_lock);
690 return err;
691}
692
693
694/**
695 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
696 * The resource will be reallocated with a new size if it was already allocated
697 * @root: root resource descriptor
698 * @new: resource descriptor desired by caller
699 * @size: requested resource region size
700 * @min: minimum boundary to allocate
701 * @max: maximum boundary to allocate
702 * @align: alignment requested, in bytes
703 * @alignf: alignment function, optional, called if not NULL
704 * @alignf_data: arbitrary data to pass to the @alignf function
705 */
706int allocate_resource(struct resource *root, struct resource *new,
707 resource_size_t size, resource_size_t min,
708 resource_size_t max, resource_size_t align,
709 resource_size_t (*alignf)(void *,
710 const struct resource *,
711 resource_size_t,
712 resource_size_t),
713 void *alignf_data)
714{
715 int err;
716 struct resource_constraint constraint;
717
718 if (!alignf)
719 alignf = simple_align_resource;
720
721 constraint.min = min;
722 constraint.max = max;
723 constraint.align = align;
724 constraint.alignf = alignf;
725 constraint.alignf_data = alignf_data;
726
727 if ( new->parent ) {
728 /* resource is already allocated, try reallocating with
729 the new constraints */
730 return reallocate_resource(root, new, size, &constraint);
731 }
732
733 write_lock(&resource_lock);
734 err = find_resource(root, new, size, &constraint);
735 if (err >= 0 && __request_resource(root, new))
736 err = -EBUSY;
737 write_unlock(&resource_lock);
738 return err;
739}
740
741EXPORT_SYMBOL(allocate_resource);
742
743/**
744 * lookup_resource - find an existing resource by a resource start address
745 * @root: root resource descriptor
746 * @start: resource start address
747 *
748 * Returns a pointer to the resource if found, NULL otherwise
749 */
750struct resource *lookup_resource(struct resource *root, resource_size_t start)
751{
752 struct resource *res;
753
754 read_lock(&resource_lock);
755 for (res = root->child; res; res = res->sibling) {
756 if (res->start == start)
757 break;
758 }
759 read_unlock(&resource_lock);
760
761 return res;
762}
763
764/*
765 * Insert a resource into the resource tree. If successful, return NULL,
766 * otherwise return the conflicting resource (compare to __request_resource())
767 */
768static struct resource * __insert_resource(struct resource *parent, struct resource *new)
769{
770 struct resource *first, *next;
771
772 for (;; parent = first) {
773 first = __request_resource(parent, new);
774 if (!first)
775 return first;
776
777 if (first == parent)
778 return first;
779 if (WARN_ON(first == new)) /* duplicated insertion */
780 return first;
781
782 if ((first->start > new->start) || (first->end < new->end))
783 break;
784 if ((first->start == new->start) && (first->end == new->end))
785 break;
786 }
787
788 for (next = first; ; next = next->sibling) {
789 /* Partial overlap? Bad, and unfixable */
790 if (next->start < new->start || next->end > new->end)
791 return next;
792 if (!next->sibling)
793 break;
794 if (next->sibling->start > new->end)
795 break;
796 }
797
798 new->parent = parent;
799 new->sibling = next->sibling;
800 new->child = first;
801
802 next->sibling = NULL;
803 for (next = first; next; next = next->sibling)
804 next->parent = new;
805
806 if (parent->child == first) {
807 parent->child = new;
808 } else {
809 next = parent->child;
810 while (next->sibling != first)
811 next = next->sibling;
812 next->sibling = new;
813 }
814 return NULL;
815}
816
817/**
818 * insert_resource_conflict - Inserts resource in the resource tree
819 * @parent: parent of the new resource
820 * @new: new resource to insert
821 *
822 * Returns 0 on success, conflict resource if the resource can't be inserted.
823 *
824 * This function is equivalent to request_resource_conflict when no conflict
825 * happens. If a conflict happens, and the conflicting resources
826 * entirely fit within the range of the new resource, then the new
827 * resource is inserted and the conflicting resources become children of
828 * the new resource.
829 *
830 * This function is intended for producers of resources, such as FW modules
831 * and bus drivers.
832 */
833struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
834{
835 struct resource *conflict;
836
837 write_lock(&resource_lock);
838 conflict = __insert_resource(parent, new);
839 write_unlock(&resource_lock);
840 return conflict;
841}
842
843/**
844 * insert_resource - Inserts a resource in the resource tree
845 * @parent: parent of the new resource
846 * @new: new resource to insert
847 *
848 * Returns 0 on success, -EBUSY if the resource can't be inserted.
849 *
850 * This function is intended for producers of resources, such as FW modules
851 * and bus drivers.
852 */
853int insert_resource(struct resource *parent, struct resource *new)
854{
855 struct resource *conflict;
856
857 conflict = insert_resource_conflict(parent, new);
858 return conflict ? -EBUSY : 0;
859}
860EXPORT_SYMBOL_GPL(insert_resource);
861
862/**
863 * insert_resource_expand_to_fit - Insert a resource into the resource tree
864 * @root: root resource descriptor
865 * @new: new resource to insert
866 *
867 * Insert a resource into the resource tree, possibly expanding it in order
868 * to make it encompass any conflicting resources.
869 */
870void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
871{
872 if (new->parent)
873 return;
874
875 write_lock(&resource_lock);
876 for (;;) {
877 struct resource *conflict;
878
879 conflict = __insert_resource(root, new);
880 if (!conflict)
881 break;
882 if (conflict == root)
883 break;
884
885 /* Ok, expand resource to cover the conflict, then try again .. */
886 if (conflict->start < new->start)
887 new->start = conflict->start;
888 if (conflict->end > new->end)
889 new->end = conflict->end;
890
891 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
892 }
893 write_unlock(&resource_lock);
894}
895/*
896 * Not for general consumption, only early boot memory map parsing, PCI
897 * resource discovery, and late discovery of CXL resources are expected
898 * to use this interface. The former are built-in and only the latter,
899 * CXL, is a module.
900 */
901EXPORT_SYMBOL_NS_GPL(insert_resource_expand_to_fit, CXL);
902
903/**
904 * remove_resource - Remove a resource in the resource tree
905 * @old: resource to remove
906 *
907 * Returns 0 on success, -EINVAL if the resource is not valid.
908 *
909 * This function removes a resource previously inserted by insert_resource()
910 * or insert_resource_conflict(), and moves the children (if any) up to
911 * where they were before. insert_resource() and insert_resource_conflict()
912 * insert a new resource, and move any conflicting resources down to the
913 * children of the new resource.
914 *
915 * insert_resource(), insert_resource_conflict() and remove_resource() are
916 * intended for producers of resources, such as FW modules and bus drivers.
917 */
918int remove_resource(struct resource *old)
919{
920 int retval;
921
922 write_lock(&resource_lock);
923 retval = __release_resource(old, false);
924 write_unlock(&resource_lock);
925 return retval;
926}
927EXPORT_SYMBOL_GPL(remove_resource);
928
929static int __adjust_resource(struct resource *res, resource_size_t start,
930 resource_size_t size)
931{
932 struct resource *tmp, *parent = res->parent;
933 resource_size_t end = start + size - 1;
934 int result = -EBUSY;
935
936 if (!parent)
937 goto skip;
938
939 if ((start < parent->start) || (end > parent->end))
940 goto out;
941
942 if (res->sibling && (res->sibling->start <= end))
943 goto out;
944
945 tmp = parent->child;
946 if (tmp != res) {
947 while (tmp->sibling != res)
948 tmp = tmp->sibling;
949 if (start <= tmp->end)
950 goto out;
951 }
952
953skip:
954 for (tmp = res->child; tmp; tmp = tmp->sibling)
955 if ((tmp->start < start) || (tmp->end > end))
956 goto out;
957
958 res->start = start;
959 res->end = end;
960 result = 0;
961
962 out:
963 return result;
964}
965
966/**
967 * adjust_resource - modify a resource's start and size
968 * @res: resource to modify
969 * @start: new start value
970 * @size: new size
971 *
972 * Given an existing resource, change its start and size to match the
973 * arguments. Returns 0 on success, -EBUSY if it can't fit.
974 * Existing children of the resource are assumed to be immutable.
975 */
976int adjust_resource(struct resource *res, resource_size_t start,
977 resource_size_t size)
978{
979 int result;
980
981 write_lock(&resource_lock);
982 result = __adjust_resource(res, start, size);
983 write_unlock(&resource_lock);
984 return result;
985}
986EXPORT_SYMBOL(adjust_resource);
987
988static void __init
989__reserve_region_with_split(struct resource *root, resource_size_t start,
990 resource_size_t end, const char *name)
991{
992 struct resource *parent = root;
993 struct resource *conflict;
994 struct resource *res = alloc_resource(GFP_ATOMIC);
995 struct resource *next_res = NULL;
996 int type = resource_type(root);
997
998 if (!res)
999 return;
1000
1001 res->name = name;
1002 res->start = start;
1003 res->end = end;
1004 res->flags = type | IORESOURCE_BUSY;
1005 res->desc = IORES_DESC_NONE;
1006
1007 while (1) {
1008
1009 conflict = __request_resource(parent, res);
1010 if (!conflict) {
1011 if (!next_res)
1012 break;
1013 res = next_res;
1014 next_res = NULL;
1015 continue;
1016 }
1017
1018 /* conflict covered whole area */
1019 if (conflict->start <= res->start &&
1020 conflict->end >= res->end) {
1021 free_resource(res);
1022 WARN_ON(next_res);
1023 break;
1024 }
1025
1026 /* failed, split and try again */
1027 if (conflict->start > res->start) {
1028 end = res->end;
1029 res->end = conflict->start - 1;
1030 if (conflict->end < end) {
1031 next_res = alloc_resource(GFP_ATOMIC);
1032 if (!next_res) {
1033 free_resource(res);
1034 break;
1035 }
1036 next_res->name = name;
1037 next_res->start = conflict->end + 1;
1038 next_res->end = end;
1039 next_res->flags = type | IORESOURCE_BUSY;
1040 next_res->desc = IORES_DESC_NONE;
1041 }
1042 } else {
1043 res->start = conflict->end + 1;
1044 }
1045 }
1046
1047}
1048
1049void __init
1050reserve_region_with_split(struct resource *root, resource_size_t start,
1051 resource_size_t end, const char *name)
1052{
1053 int abort = 0;
1054
1055 write_lock(&resource_lock);
1056 if (root->start > start || root->end < end) {
1057 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
1058 (unsigned long long)start, (unsigned long long)end,
1059 root);
1060 if (start > root->end || end < root->start)
1061 abort = 1;
1062 else {
1063 if (end > root->end)
1064 end = root->end;
1065 if (start < root->start)
1066 start = root->start;
1067 pr_err("fixing request to [0x%llx-0x%llx]\n",
1068 (unsigned long long)start,
1069 (unsigned long long)end);
1070 }
1071 dump_stack();
1072 }
1073 if (!abort)
1074 __reserve_region_with_split(root, start, end, name);
1075 write_unlock(&resource_lock);
1076}
1077
1078/**
1079 * resource_alignment - calculate resource's alignment
1080 * @res: resource pointer
1081 *
1082 * Returns alignment on success, 0 (invalid alignment) on failure.
1083 */
1084resource_size_t resource_alignment(struct resource *res)
1085{
1086 switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
1087 case IORESOURCE_SIZEALIGN:
1088 return resource_size(res);
1089 case IORESOURCE_STARTALIGN:
1090 return res->start;
1091 default:
1092 return 0;
1093 }
1094}
1095
1096/*
1097 * This is compatibility stuff for IO resources.
1098 *
1099 * Note how this, unlike the above, knows about
1100 * the IO flag meanings (busy etc).
1101 *
1102 * request_region creates a new busy region.
1103 *
1104 * release_region releases a matching busy region.
1105 */
1106
1107static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1108
1109static struct inode *iomem_inode;
1110
1111#ifdef CONFIG_IO_STRICT_DEVMEM
1112static void revoke_iomem(struct resource *res)
1113{
1114 /* pairs with smp_store_release() in iomem_init_inode() */
1115 struct inode *inode = smp_load_acquire(&iomem_inode);
1116
1117 /*
1118 * Check that the initialization has completed. Losing the race
1119 * is ok because it means drivers are claiming resources before
1120 * the fs_initcall level of init and prevent iomem_get_mapping users
1121 * from establishing mappings.
1122 */
1123 if (!inode)
1124 return;
1125
1126 /*
1127 * The expectation is that the driver has successfully marked
1128 * the resource busy by this point, so devmem_is_allowed()
1129 * should start returning false, however for performance this
1130 * does not iterate the entire resource range.
1131 */
1132 if (devmem_is_allowed(PHYS_PFN(res->start)) &&
1133 devmem_is_allowed(PHYS_PFN(res->end))) {
1134 /*
1135 * *cringe* iomem=relaxed says "go ahead, what's the
1136 * worst that can happen?"
1137 */
1138 return;
1139 }
1140
1141 unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
1142}
1143#else
1144static void revoke_iomem(struct resource *res) {}
1145#endif
1146
1147struct address_space *iomem_get_mapping(void)
1148{
1149 /*
1150 * This function is only called from file open paths, hence guaranteed
1151 * that fs_initcalls have completed and no need to check for NULL. But
1152 * since revoke_iomem can be called before the initcall we still need
1153 * the barrier to appease checkers.
1154 */
1155 return smp_load_acquire(&iomem_inode)->i_mapping;
1156}
1157
1158static int __request_region_locked(struct resource *res, struct resource *parent,
1159 resource_size_t start, resource_size_t n,
1160 const char *name, int flags)
1161{
1162 DECLARE_WAITQUEUE(wait, current);
1163
1164 res->name = name;
1165 res->start = start;
1166 res->end = start + n - 1;
1167
1168 for (;;) {
1169 struct resource *conflict;
1170
1171 res->flags = resource_type(parent) | resource_ext_type(parent);
1172 res->flags |= IORESOURCE_BUSY | flags;
1173 res->desc = parent->desc;
1174
1175 conflict = __request_resource(parent, res);
1176 if (!conflict)
1177 break;
1178 /*
1179 * mm/hmm.c reserves physical addresses which then
1180 * become unavailable to other users. Conflicts are
1181 * not expected. Warn to aid debugging if encountered.
1182 */
1183 if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
1184 pr_warn("Unaddressable device %s %pR conflicts with %pR",
1185 conflict->name, conflict, res);
1186 }
1187 if (conflict != parent) {
1188 if (!(conflict->flags & IORESOURCE_BUSY)) {
1189 parent = conflict;
1190 continue;
1191 }
1192 }
1193 if (conflict->flags & flags & IORESOURCE_MUXED) {
1194 add_wait_queue(&muxed_resource_wait, &wait);
1195 write_unlock(&resource_lock);
1196 set_current_state(TASK_UNINTERRUPTIBLE);
1197 schedule();
1198 remove_wait_queue(&muxed_resource_wait, &wait);
1199 write_lock(&resource_lock);
1200 continue;
1201 }
1202 /* Uhhuh, that didn't work out.. */
1203 return -EBUSY;
1204 }
1205
1206 return 0;
1207}
1208
1209/**
1210 * __request_region - create a new busy resource region
1211 * @parent: parent resource descriptor
1212 * @start: resource start address
1213 * @n: resource region size
1214 * @name: reserving caller's ID string
1215 * @flags: IO resource flags
1216 */
1217struct resource *__request_region(struct resource *parent,
1218 resource_size_t start, resource_size_t n,
1219 const char *name, int flags)
1220{
1221 struct resource *res = alloc_resource(GFP_KERNEL);
1222 int ret;
1223
1224 if (!res)
1225 return NULL;
1226
1227 write_lock(&resource_lock);
1228 ret = __request_region_locked(res, parent, start, n, name, flags);
1229 write_unlock(&resource_lock);
1230
1231 if (ret) {
1232 free_resource(res);
1233 return NULL;
1234 }
1235
1236 if (parent == &iomem_resource)
1237 revoke_iomem(res);
1238
1239 return res;
1240}
1241EXPORT_SYMBOL(__request_region);
1242
1243/**
1244 * __release_region - release a previously reserved resource region
1245 * @parent: parent resource descriptor
1246 * @start: resource start address
1247 * @n: resource region size
1248 *
1249 * The described resource region must match a currently busy region.
1250 */
1251void __release_region(struct resource *parent, resource_size_t start,
1252 resource_size_t n)
1253{
1254 struct resource **p;
1255 resource_size_t end;
1256
1257 p = &parent->child;
1258 end = start + n - 1;
1259
1260 write_lock(&resource_lock);
1261
1262 for (;;) {
1263 struct resource *res = *p;
1264
1265 if (!res)
1266 break;
1267 if (res->start <= start && res->end >= end) {
1268 if (!(res->flags & IORESOURCE_BUSY)) {
1269 p = &res->child;
1270 continue;
1271 }
1272 if (res->start != start || res->end != end)
1273 break;
1274 *p = res->sibling;
1275 write_unlock(&resource_lock);
1276 if (res->flags & IORESOURCE_MUXED)
1277 wake_up(&muxed_resource_wait);
1278 free_resource(res);
1279 return;
1280 }
1281 p = &res->sibling;
1282 }
1283
1284 write_unlock(&resource_lock);
1285
1286 printk(KERN_WARNING "Trying to free nonexistent resource "
1287 "<%016llx-%016llx>\n", (unsigned long long)start,
1288 (unsigned long long)end);
1289}
1290EXPORT_SYMBOL(__release_region);
1291
1292#ifdef CONFIG_MEMORY_HOTREMOVE
1293/**
1294 * release_mem_region_adjustable - release a previously reserved memory region
1295 * @start: resource start address
1296 * @size: resource region size
1297 *
1298 * This interface is intended for memory hot-delete. The requested region
1299 * is released from a currently busy memory resource. The requested region
1300 * must either match exactly or fit into a single busy resource entry. In
1301 * the latter case, the remaining resource is adjusted accordingly.
1302 * Existing children of the busy memory resource must be immutable in the
1303 * request.
1304 *
1305 * Note:
1306 * - Additional release conditions, such as overlapping region, can be
1307 * supported after they are confirmed as valid cases.
1308 * - When a busy memory resource gets split into two entries, the code
1309 * assumes that all children remain in the lower address entry for
1310 * simplicity. Enhance this logic when necessary.
1311 */
1312void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
1313{
1314 struct resource *parent = &iomem_resource;
1315 struct resource *new_res = NULL;
1316 bool alloc_nofail = false;
1317 struct resource **p;
1318 struct resource *res;
1319 resource_size_t end;
1320
1321 end = start + size - 1;
1322 if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
1323 return;
1324
1325 /*
1326 * We free up quite a lot of memory on memory hotunplug (esp., memap),
1327 * just before releasing the region. This is highly unlikely to
1328 * fail - let's play save and make it never fail as the caller cannot
1329 * perform any error handling (e.g., trying to re-add memory will fail
1330 * similarly).
1331 */
1332retry:
1333 new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
1334
1335 p = &parent->child;
1336 write_lock(&resource_lock);
1337
1338 while ((res = *p)) {
1339 if (res->start >= end)
1340 break;
1341
1342 /* look for the next resource if it does not fit into */
1343 if (res->start > start || res->end < end) {
1344 p = &res->sibling;
1345 continue;
1346 }
1347
1348 /*
1349 * All memory regions added from memory-hotplug path have the
1350 * flag IORESOURCE_SYSTEM_RAM. If the resource does not have
1351 * this flag, we know that we are dealing with a resource coming
1352 * from HMM/devm. HMM/devm use another mechanism to add/release
1353 * a resource. This goes via devm_request_mem_region and
1354 * devm_release_mem_region.
1355 * HMM/devm take care to release their resources when they want,
1356 * so if we are dealing with them, let us just back off here.
1357 */
1358 if (!(res->flags & IORESOURCE_SYSRAM)) {
1359 break;
1360 }
1361
1362 if (!(res->flags & IORESOURCE_MEM))
1363 break;
1364
1365 if (!(res->flags & IORESOURCE_BUSY)) {
1366 p = &res->child;
1367 continue;
1368 }
1369
1370 /* found the target resource; let's adjust accordingly */
1371 if (res->start == start && res->end == end) {
1372 /* free the whole entry */
1373 *p = res->sibling;
1374 free_resource(res);
1375 } else if (res->start == start && res->end != end) {
1376 /* adjust the start */
1377 WARN_ON_ONCE(__adjust_resource(res, end + 1,
1378 res->end - end));
1379 } else if (res->start != start && res->end == end) {
1380 /* adjust the end */
1381 WARN_ON_ONCE(__adjust_resource(res, res->start,
1382 start - res->start));
1383 } else {
1384 /* split into two entries - we need a new resource */
1385 if (!new_res) {
1386 new_res = alloc_resource(GFP_ATOMIC);
1387 if (!new_res) {
1388 alloc_nofail = true;
1389 write_unlock(&resource_lock);
1390 goto retry;
1391 }
1392 }
1393 new_res->name = res->name;
1394 new_res->start = end + 1;
1395 new_res->end = res->end;
1396 new_res->flags = res->flags;
1397 new_res->desc = res->desc;
1398 new_res->parent = res->parent;
1399 new_res->sibling = res->sibling;
1400 new_res->child = NULL;
1401
1402 if (WARN_ON_ONCE(__adjust_resource(res, res->start,
1403 start - res->start)))
1404 break;
1405 res->sibling = new_res;
1406 new_res = NULL;
1407 }
1408
1409 break;
1410 }
1411
1412 write_unlock(&resource_lock);
1413 free_resource(new_res);
1414}
1415#endif /* CONFIG_MEMORY_HOTREMOVE */
1416
1417#ifdef CONFIG_MEMORY_HOTPLUG
1418static bool system_ram_resources_mergeable(struct resource *r1,
1419 struct resource *r2)
1420{
1421 /* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
1422 return r1->flags == r2->flags && r1->end + 1 == r2->start &&
1423 r1->name == r2->name && r1->desc == r2->desc &&
1424 !r1->child && !r2->child;
1425}
1426
1427/**
1428 * merge_system_ram_resource - mark the System RAM resource mergeable and try to
1429 * merge it with adjacent, mergeable resources
1430 * @res: resource descriptor
1431 *
1432 * This interface is intended for memory hotplug, whereby lots of contiguous
1433 * system ram resources are added (e.g., via add_memory*()) by a driver, and
1434 * the actual resource boundaries are not of interest (e.g., it might be
1435 * relevant for DIMMs). Only resources that are marked mergeable, that have the
1436 * same parent, and that don't have any children are considered. All mergeable
1437 * resources must be immutable during the request.
1438 *
1439 * Note:
1440 * - The caller has to make sure that no pointers to resources that are
1441 * marked mergeable are used anymore after this call - the resource might
1442 * be freed and the pointer might be stale!
1443 * - release_mem_region_adjustable() will split on demand on memory hotunplug
1444 */
1445void merge_system_ram_resource(struct resource *res)
1446{
1447 const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
1448 struct resource *cur;
1449
1450 if (WARN_ON_ONCE((res->flags & flags) != flags))
1451 return;
1452
1453 write_lock(&resource_lock);
1454 res->flags |= IORESOURCE_SYSRAM_MERGEABLE;
1455
1456 /* Try to merge with next item in the list. */
1457 cur = res->sibling;
1458 if (cur && system_ram_resources_mergeable(res, cur)) {
1459 res->end = cur->end;
1460 res->sibling = cur->sibling;
1461 free_resource(cur);
1462 }
1463
1464 /* Try to merge with previous item in the list. */
1465 cur = res->parent->child;
1466 while (cur && cur->sibling != res)
1467 cur = cur->sibling;
1468 if (cur && system_ram_resources_mergeable(cur, res)) {
1469 cur->end = res->end;
1470 cur->sibling = res->sibling;
1471 free_resource(res);
1472 }
1473 write_unlock(&resource_lock);
1474}
1475#endif /* CONFIG_MEMORY_HOTPLUG */
1476
1477/*
1478 * Managed region resource
1479 */
1480static void devm_resource_release(struct device *dev, void *ptr)
1481{
1482 struct resource **r = ptr;
1483
1484 release_resource(*r);
1485}
1486
1487/**
1488 * devm_request_resource() - request and reserve an I/O or memory resource
1489 * @dev: device for which to request the resource
1490 * @root: root of the resource tree from which to request the resource
1491 * @new: descriptor of the resource to request
1492 *
1493 * This is a device-managed version of request_resource(). There is usually
1494 * no need to release resources requested by this function explicitly since
1495 * that will be taken care of when the device is unbound from its driver.
1496 * If for some reason the resource needs to be released explicitly, because
1497 * of ordering issues for example, drivers must call devm_release_resource()
1498 * rather than the regular release_resource().
1499 *
1500 * When a conflict is detected between any existing resources and the newly
1501 * requested resource, an error message will be printed.
1502 *
1503 * Returns 0 on success or a negative error code on failure.
1504 */
1505int devm_request_resource(struct device *dev, struct resource *root,
1506 struct resource *new)
1507{
1508 struct resource *conflict, **ptr;
1509
1510 ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
1511 if (!ptr)
1512 return -ENOMEM;
1513
1514 *ptr = new;
1515
1516 conflict = request_resource_conflict(root, new);
1517 if (conflict) {
1518 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
1519 new, conflict->name, conflict);
1520 devres_free(ptr);
1521 return -EBUSY;
1522 }
1523
1524 devres_add(dev, ptr);
1525 return 0;
1526}
1527EXPORT_SYMBOL(devm_request_resource);
1528
1529static int devm_resource_match(struct device *dev, void *res, void *data)
1530{
1531 struct resource **ptr = res;
1532
1533 return *ptr == data;
1534}
1535
1536/**
1537 * devm_release_resource() - release a previously requested resource
1538 * @dev: device for which to release the resource
1539 * @new: descriptor of the resource to release
1540 *
1541 * Releases a resource previously requested using devm_request_resource().
1542 */
1543void devm_release_resource(struct device *dev, struct resource *new)
1544{
1545 WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
1546 new));
1547}
1548EXPORT_SYMBOL(devm_release_resource);
1549
1550struct region_devres {
1551 struct resource *parent;
1552 resource_size_t start;
1553 resource_size_t n;
1554};
1555
1556static void devm_region_release(struct device *dev, void *res)
1557{
1558 struct region_devres *this = res;
1559
1560 __release_region(this->parent, this->start, this->n);
1561}
1562
1563static int devm_region_match(struct device *dev, void *res, void *match_data)
1564{
1565 struct region_devres *this = res, *match = match_data;
1566
1567 return this->parent == match->parent &&
1568 this->start == match->start && this->n == match->n;
1569}
1570
1571struct resource *
1572__devm_request_region(struct device *dev, struct resource *parent,
1573 resource_size_t start, resource_size_t n, const char *name)
1574{
1575 struct region_devres *dr = NULL;
1576 struct resource *res;
1577
1578 dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1579 GFP_KERNEL);
1580 if (!dr)
1581 return NULL;
1582
1583 dr->parent = parent;
1584 dr->start = start;
1585 dr->n = n;
1586
1587 res = __request_region(parent, start, n, name, 0);
1588 if (res)
1589 devres_add(dev, dr);
1590 else
1591 devres_free(dr);
1592
1593 return res;
1594}
1595EXPORT_SYMBOL(__devm_request_region);
1596
1597void __devm_release_region(struct device *dev, struct resource *parent,
1598 resource_size_t start, resource_size_t n)
1599{
1600 struct region_devres match_data = { parent, start, n };
1601
1602 __release_region(parent, start, n);
1603 WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1604 &match_data));
1605}
1606EXPORT_SYMBOL(__devm_release_region);
1607
1608/*
1609 * Reserve I/O ports or memory based on "reserve=" kernel parameter.
1610 */
1611#define MAXRESERVE 4
1612static int __init reserve_setup(char *str)
1613{
1614 static int reserved;
1615 static struct resource reserve[MAXRESERVE];
1616
1617 for (;;) {
1618 unsigned int io_start, io_num;
1619 int x = reserved;
1620 struct resource *parent;
1621
1622 if (get_option(&str, &io_start) != 2)
1623 break;
1624 if (get_option(&str, &io_num) == 0)
1625 break;
1626 if (x < MAXRESERVE) {
1627 struct resource *res = reserve + x;
1628
1629 /*
1630 * If the region starts below 0x10000, we assume it's
1631 * I/O port space; otherwise assume it's memory.
1632 */
1633 if (io_start < 0x10000) {
1634 res->flags = IORESOURCE_IO;
1635 parent = &ioport_resource;
1636 } else {
1637 res->flags = IORESOURCE_MEM;
1638 parent = &iomem_resource;
1639 }
1640 res->name = "reserved";
1641 res->start = io_start;
1642 res->end = io_start + io_num - 1;
1643 res->flags |= IORESOURCE_BUSY;
1644 res->desc = IORES_DESC_NONE;
1645 res->child = NULL;
1646 if (request_resource(parent, res) == 0)
1647 reserved = x+1;
1648 }
1649 }
1650 return 1;
1651}
1652__setup("reserve=", reserve_setup);
1653
1654/*
1655 * Check if the requested addr and size spans more than any slot in the
1656 * iomem resource tree.
1657 */
1658int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1659{
1660 struct resource *p = &iomem_resource;
1661 int err = 0;
1662 loff_t l;
1663
1664 read_lock(&resource_lock);
1665 for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1666 /*
1667 * We can probably skip the resources without
1668 * IORESOURCE_IO attribute?
1669 */
1670 if (p->start >= addr + size)
1671 continue;
1672 if (p->end < addr)
1673 continue;
1674 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1675 PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1676 continue;
1677 /*
1678 * if a resource is "BUSY", it's not a hardware resource
1679 * but a driver mapping of such a resource; we don't want
1680 * to warn for those; some drivers legitimately map only
1681 * partial hardware resources. (example: vesafb)
1682 */
1683 if (p->flags & IORESOURCE_BUSY)
1684 continue;
1685
1686 printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1687 (unsigned long long)addr,
1688 (unsigned long long)(addr + size - 1),
1689 p->name, p);
1690 err = -1;
1691 break;
1692 }
1693 read_unlock(&resource_lock);
1694
1695 return err;
1696}
1697
1698#ifdef CONFIG_STRICT_DEVMEM
1699static int strict_iomem_checks = 1;
1700#else
1701static int strict_iomem_checks;
1702#endif
1703
1704/*
1705 * Check if an address is exclusive to the kernel and must not be mapped to
1706 * user space, for example, via /dev/mem.
1707 *
1708 * Returns true if exclusive to the kernel, otherwise returns false.
1709 */
1710bool iomem_is_exclusive(u64 addr)
1711{
1712 const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
1713 IORESOURCE_EXCLUSIVE;
1714 bool skip_children = false, err = false;
1715 int size = PAGE_SIZE;
1716 struct resource *p;
1717
1718 addr = addr & PAGE_MASK;
1719
1720 read_lock(&resource_lock);
1721 for_each_resource(&iomem_resource, p, skip_children) {
1722 if (p->start >= addr + size)
1723 break;
1724 if (p->end < addr) {
1725 skip_children = true;
1726 continue;
1727 }
1728 skip_children = false;
1729
1730 /*
1731 * IORESOURCE_SYSTEM_RAM resources are exclusive if
1732 * IORESOURCE_EXCLUSIVE is set, even if they
1733 * are not busy and even if "iomem=relaxed" is set. The
1734 * responsible driver dynamically adds/removes system RAM within
1735 * such an area and uncontrolled access is dangerous.
1736 */
1737 if ((p->flags & exclusive_system_ram) == exclusive_system_ram) {
1738 err = true;
1739 break;
1740 }
1741
1742 /*
1743 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
1744 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
1745 * resource is busy.
1746 */
1747 if (!strict_iomem_checks || !(p->flags & IORESOURCE_BUSY))
1748 continue;
1749 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
1750 || p->flags & IORESOURCE_EXCLUSIVE) {
1751 err = true;
1752 break;
1753 }
1754 }
1755 read_unlock(&resource_lock);
1756
1757 return err;
1758}
1759
1760struct resource_entry *resource_list_create_entry(struct resource *res,
1761 size_t extra_size)
1762{
1763 struct resource_entry *entry;
1764
1765 entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
1766 if (entry) {
1767 INIT_LIST_HEAD(&entry->node);
1768 entry->res = res ? res : &entry->__res;
1769 }
1770
1771 return entry;
1772}
1773EXPORT_SYMBOL(resource_list_create_entry);
1774
1775void resource_list_free(struct list_head *head)
1776{
1777 struct resource_entry *entry, *tmp;
1778
1779 list_for_each_entry_safe(entry, tmp, head, node)
1780 resource_list_destroy_entry(entry);
1781}
1782EXPORT_SYMBOL(resource_list_free);
1783
1784#ifdef CONFIG_GET_FREE_REGION
1785#define GFR_DESCENDING (1UL << 0)
1786#define GFR_REQUEST_REGION (1UL << 1)
1787#define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
1788
1789static resource_size_t gfr_start(struct resource *base, resource_size_t size,
1790 resource_size_t align, unsigned long flags)
1791{
1792 if (flags & GFR_DESCENDING) {
1793 resource_size_t end;
1794
1795 end = min_t(resource_size_t, base->end,
1796 (1ULL << MAX_PHYSMEM_BITS) - 1);
1797 return end - size + 1;
1798 }
1799
1800 return ALIGN(base->start, align);
1801}
1802
1803static bool gfr_continue(struct resource *base, resource_size_t addr,
1804 resource_size_t size, unsigned long flags)
1805{
1806 if (flags & GFR_DESCENDING)
1807 return addr > size && addr >= base->start;
1808 /*
1809 * In the ascend case be careful that the last increment by
1810 * @size did not wrap 0.
1811 */
1812 return addr > addr - size &&
1813 addr <= min_t(resource_size_t, base->end,
1814 (1ULL << MAX_PHYSMEM_BITS) - 1);
1815}
1816
1817static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
1818 unsigned long flags)
1819{
1820 if (flags & GFR_DESCENDING)
1821 return addr - size;
1822 return addr + size;
1823}
1824
1825static void remove_free_mem_region(void *_res)
1826{
1827 struct resource *res = _res;
1828
1829 if (res->parent)
1830 remove_resource(res);
1831 free_resource(res);
1832}
1833
1834static struct resource *
1835get_free_mem_region(struct device *dev, struct resource *base,
1836 resource_size_t size, const unsigned long align,
1837 const char *name, const unsigned long desc,
1838 const unsigned long flags)
1839{
1840 resource_size_t addr;
1841 struct resource *res;
1842 struct region_devres *dr = NULL;
1843
1844 size = ALIGN(size, align);
1845
1846 res = alloc_resource(GFP_KERNEL);
1847 if (!res)
1848 return ERR_PTR(-ENOMEM);
1849
1850 if (dev && (flags & GFR_REQUEST_REGION)) {
1851 dr = devres_alloc(devm_region_release,
1852 sizeof(struct region_devres), GFP_KERNEL);
1853 if (!dr) {
1854 free_resource(res);
1855 return ERR_PTR(-ENOMEM);
1856 }
1857 } else if (dev) {
1858 if (devm_add_action_or_reset(dev, remove_free_mem_region, res))
1859 return ERR_PTR(-ENOMEM);
1860 }
1861
1862 write_lock(&resource_lock);
1863 for (addr = gfr_start(base, size, align, flags);
1864 gfr_continue(base, addr, size, flags);
1865 addr = gfr_next(addr, size, flags)) {
1866 if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
1867 REGION_DISJOINT)
1868 continue;
1869
1870 if (flags & GFR_REQUEST_REGION) {
1871 if (__request_region_locked(res, &iomem_resource, addr,
1872 size, name, 0))
1873 break;
1874
1875 if (dev) {
1876 dr->parent = &iomem_resource;
1877 dr->start = addr;
1878 dr->n = size;
1879 devres_add(dev, dr);
1880 }
1881
1882 res->desc = desc;
1883 write_unlock(&resource_lock);
1884
1885
1886 /*
1887 * A driver is claiming this region so revoke any
1888 * mappings.
1889 */
1890 revoke_iomem(res);
1891 } else {
1892 res->start = addr;
1893 res->end = addr + size - 1;
1894 res->name = name;
1895 res->desc = desc;
1896 res->flags = IORESOURCE_MEM;
1897
1898 /*
1899 * Only succeed if the resource hosts an exclusive
1900 * range after the insert
1901 */
1902 if (__insert_resource(base, res) || res->child)
1903 break;
1904
1905 write_unlock(&resource_lock);
1906 }
1907
1908 return res;
1909 }
1910 write_unlock(&resource_lock);
1911
1912 if (flags & GFR_REQUEST_REGION) {
1913 free_resource(res);
1914 devres_free(dr);
1915 } else if (dev)
1916 devm_release_action(dev, remove_free_mem_region, res);
1917
1918 return ERR_PTR(-ERANGE);
1919}
1920
1921/**
1922 * devm_request_free_mem_region - find free region for device private memory
1923 *
1924 * @dev: device struct to bind the resource to
1925 * @size: size in bytes of the device memory to add
1926 * @base: resource tree to look in
1927 *
1928 * This function tries to find an empty range of physical address big enough to
1929 * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
1930 * memory, which in turn allocates struct pages.
1931 */
1932struct resource *devm_request_free_mem_region(struct device *dev,
1933 struct resource *base, unsigned long size)
1934{
1935 unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
1936
1937 return get_free_mem_region(dev, base, size, GFR_DEFAULT_ALIGN,
1938 dev_name(dev),
1939 IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
1940}
1941EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
1942
1943struct resource *request_free_mem_region(struct resource *base,
1944 unsigned long size, const char *name)
1945{
1946 unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
1947
1948 return get_free_mem_region(NULL, base, size, GFR_DEFAULT_ALIGN, name,
1949 IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
1950}
1951EXPORT_SYMBOL_GPL(request_free_mem_region);
1952
1953/**
1954 * alloc_free_mem_region - find a free region relative to @base
1955 * @base: resource that will parent the new resource
1956 * @size: size in bytes of memory to allocate from @base
1957 * @align: alignment requirements for the allocation
1958 * @name: resource name
1959 *
1960 * Buses like CXL, that can dynamically instantiate new memory regions,
1961 * need a method to allocate physical address space for those regions.
1962 * Allocate and insert a new resource to cover a free, unclaimed by a
1963 * descendant of @base, range in the span of @base.
1964 */
1965struct resource *alloc_free_mem_region(struct resource *base,
1966 unsigned long size, unsigned long align,
1967 const char *name)
1968{
1969 /* Default of ascending direction and insert resource */
1970 unsigned long flags = 0;
1971
1972 return get_free_mem_region(NULL, base, size, align, name,
1973 IORES_DESC_NONE, flags);
1974}
1975EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
1976#endif /* CONFIG_GET_FREE_REGION */
1977
1978static int __init strict_iomem(char *str)
1979{
1980 if (strstr(str, "relaxed"))
1981 strict_iomem_checks = 0;
1982 if (strstr(str, "strict"))
1983 strict_iomem_checks = 1;
1984 return 1;
1985}
1986
1987static int iomem_fs_init_fs_context(struct fs_context *fc)
1988{
1989 return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
1990}
1991
1992static struct file_system_type iomem_fs_type = {
1993 .name = "iomem",
1994 .owner = THIS_MODULE,
1995 .init_fs_context = iomem_fs_init_fs_context,
1996 .kill_sb = kill_anon_super,
1997};
1998
1999static int __init iomem_init_inode(void)
2000{
2001 static struct vfsmount *iomem_vfs_mount;
2002 static int iomem_fs_cnt;
2003 struct inode *inode;
2004 int rc;
2005
2006 rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt);
2007 if (rc < 0) {
2008 pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc);
2009 return rc;
2010 }
2011
2012 inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb);
2013 if (IS_ERR(inode)) {
2014 rc = PTR_ERR(inode);
2015 pr_err("Cannot allocate inode for iomem: %d\n", rc);
2016 simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt);
2017 return rc;
2018 }
2019
2020 /*
2021 * Publish iomem revocation inode initialized.
2022 * Pairs with smp_load_acquire() in revoke_iomem().
2023 */
2024 smp_store_release(&iomem_inode, inode);
2025
2026 return 0;
2027}
2028
2029fs_initcall(iomem_init_inode);
2030
2031__setup("iomem=", strict_iomem);