kernel/resource.c

   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/export.h>
  13 #include <linux/errno.h>
  14 #include <linux/ioport.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/fs.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/sched.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/device.h>
  23 #include <linux/pfn.h>
  24 #include <linux/mm.h>
  25 #include <linux/resource_ext.h>
  26 #include <asm/io.h>
  27
  28
  29 struct resource ioport_resource = {
  30         .name   = "PCI IO",
  31         .start  = 0,
  32         .end    = IO_SPACE_LIMIT,
  33         .flags  = IORESOURCE_IO,
  34 };
  35 EXPORT_SYMBOL(ioport_resource);
  36
  37 struct resource iomem_resource = {
  38         .name   = "PCI mem",
  39         .start  = 0,
  40         .end    = -1,
  41         .flags  = IORESOURCE_MEM,
  42 };
  43 EXPORT_SYMBOL(iomem_resource);
  44
  45 /* constraints to be met while allocating resources */
  46 struct resource_constraint {
  47         resource_size_t min, max, align;
  48         resource_size_t (*alignf)(void *, const struct resource *,
  49                         resource_size_t, resource_size_t);
  50         void *alignf_data;
  51 };
  52
  53 static DEFINE_RWLOCK(resource_lock);
  54
  55 /*
  56  * For memory hotplug, there is no way to free resource entries allocated
  57  * by boot mem after the system is up. So for reusing the resource entry
  58  * we need to remember the resource.
  59  */
  60 static struct resource *bootmem_resource_free;
  61 static DEFINE_SPINLOCK(bootmem_resource_lock);
  62
  63 static struct resource *next_resource(struct resource *p, bool sibling_only)
  64 {
  65         /* Caller wants to traverse through siblings only */
  66         if (sibling_only)
  67                 return p->sibling;
  68
  69         if (p->child)
  70                 return p->child;
  71         while (!p->sibling && p->parent)
  72                 p = p->parent;
  73         return p->sibling;
  74 }
  75
  76 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  77 {
  78         struct resource *p = v;
  79         (*pos)++;
  80         return (void *)next_resource(p, false);
  81 }
  82
  83 #ifdef CONFIG_PROC_FS
  84
  85 enum { MAX_IORES_LEVEL = 5 };
  86
  87 static void *r_start(struct seq_file *m, loff_t *pos)
  88         __acquires(resource_lock)
  89 {
  90         struct resource *p = PDE_DATA(file_inode(m->file));
  91         loff_t l = 0;
  92         read_lock(&resource_lock);
  93         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  94                 ;
  95         return p;
  96 }
  97
  98 static void r_stop(struct seq_file *m, void *v)
  99         __releases(resource_lock)
 100 {
 101         read_unlock(&resource_lock);
 102 }
 103
 104 static int r_show(struct seq_file *m, void *v)
 105 {
 106         struct resource *root = PDE_DATA(file_inode(m->file));
 107         struct resource *r = v, *p;
 108         unsigned long long start, end;
 109         int width = root->end < 0x10000 ? 4 : 8;
 110         int depth;
 111
 112         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
 113                 if (p->parent == root)
 114                         break;
 115
 116         if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
 117                 start = r->start;
 118                 end = r->end;
 119         } else {
 120                 start = end = 0;
 121         }
 122
 123         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
 124                         depth * 2, "",
 125                         width, start,
 126                         width, end,
 127                         r->name ? r->name : "<BAD>");
 128         return 0;
 129 }
 130
 131 static const struct seq_operations resource_op = {
 132         .start  = r_start,
 133         .next   = r_next,
 134         .stop   = r_stop,
 135         .show   = r_show,
 136 };
 137
 138 static int __init ioresources_init(void)
 139 {
 140         proc_create_seq_data("ioports", 0, NULL, &resource_op,
 141                         &ioport_resource);
 142         proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
 143         return 0;
 144 }
 145 __initcall(ioresources_init);
 146
 147 #endif /* CONFIG_PROC_FS */
 148
 149 static void free_resource(struct resource *res)
 150 {
 151         if (!res)
 152                 return;
 153
 154         if (!PageSlab(virt_to_head_page(res))) {
 155                 spin_lock(&bootmem_resource_lock);
 156                 res->sibling = bootmem_resource_free;
 157                 bootmem_resource_free = res;
 158                 spin_unlock(&bootmem_resource_lock);
 159         } else {
 160                 kfree(res);
 161         }
 162 }
 163
 164 static struct resource *alloc_resource(gfp_t flags)
 165 {
 166         struct resource *res = NULL;
 167
 168         spin_lock(&bootmem_resource_lock);
 169         if (bootmem_resource_free) {
 170                 res = bootmem_resource_free;
 171                 bootmem_resource_free = res->sibling;
 172         }
 173         spin_unlock(&bootmem_resource_lock);
 174
 175         if (res)
 176                 memset(res, 0, sizeof(struct resource));
 177         else
 178                 res = kzalloc(sizeof(struct resource), flags);
 179
 180         return res;
 181 }
 182
 183 /* Return the conflict entry if you can't request it */
 184 static struct resource * __request_resource(struct resource *root, struct resource *new)
 185 {
 186         resource_size_t start = new->start;
 187         resource_size_t end = new->end;
 188         struct resource *tmp, **p;
 189
 190         if (end < start)
 191                 return root;
 192         if (start < root->start)
 193                 return root;
 194         if (end > root->end)
 195                 return root;
 196         p = &root->child;
 197         for (;;) {
 198                 tmp = *p;
 199                 if (!tmp || tmp->start > end) {
 200                         new->sibling = tmp;
 201                         *p = new;
 202                         new->parent = root;
 203                         return NULL;
 204                 }
 205                 p = &tmp->sibling;
 206                 if (tmp->end < start)
 207                         continue;
 208                 return tmp;
 209         }
 210 }
 211
 212 static int __release_resource(struct resource *old, bool release_child)
 213 {
 214         struct resource *tmp, **p, *chd;
 215
 216         p = &old->parent->child;
 217         for (;;) {
 218                 tmp = *p;
 219                 if (!tmp)
 220                         break;
 221                 if (tmp == old) {
 222                         if (release_child || !(tmp->child)) {
 223                                 *p = tmp->sibling;
 224                         } else {
 225                                 for (chd = tmp->child;; chd = chd->sibling) {
 226                                         chd->parent = tmp->parent;
 227                                         if (!(chd->sibling))
 228                                                 break;
 229                                 }
 230                                 *p = tmp->child;
 231                                 chd->sibling = tmp->sibling;
 232                         }
 233                         old->parent = NULL;
 234                         return 0;
 235                 }
 236                 p = &tmp->sibling;
 237         }
 238         return -EINVAL;
 239 }
 240
 241 static void __release_child_resources(struct resource *r)
 242 {
 243         struct resource *tmp, *p;
 244         resource_size_t size;
 245
 246         p = r->child;
 247         r->child = NULL;
 248         while (p) {
 249                 tmp = p;
 250                 p = p->sibling;
 251
 252                 tmp->parent = NULL;
 253                 tmp->sibling = NULL;
 254                 __release_child_resources(tmp);
 255
 256                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
 257                 /* need to restore size, and keep flags */
 258                 size = resource_size(tmp);
 259                 tmp->start = 0;
 260                 tmp->end = size - 1;
 261         }
 262 }
 263
 264 void release_child_resources(struct resource *r)
 265 {
 266         write_lock(&resource_lock);
 267         __release_child_resources(r);
 268         write_unlock(&resource_lock);
 269 }
 270
 271 /**
 272  * request_resource_conflict - request and reserve an I/O or memory resource
 273  * @root: root resource descriptor
 274  * @new: resource descriptor desired by caller
 275  *
 276  * Returns 0 for success, conflict resource on error.
 277  */
 278 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 279 {
 280         struct resource *conflict;
 281
 282         write_lock(&resource_lock);
 283         conflict = __request_resource(root, new);
 284         write_unlock(&resource_lock);
 285         return conflict;
 286 }
 287
 288 /**
 289  * request_resource - request and reserve an I/O or memory resource
 290  * @root: root resource descriptor
 291  * @new: resource descriptor desired by caller
 292  *
 293  * Returns 0 for success, negative error code on error.
 294  */
 295 int request_resource(struct resource *root, struct resource *new)
 296 {
 297         struct resource *conflict;
 298
 299         conflict = request_resource_conflict(root, new);
 300         return conflict ? -EBUSY : 0;
 301 }
 302
 303 EXPORT_SYMBOL(request_resource);
 304
 305 /**
 306  * release_resource - release a previously reserved resource
 307  * @old: resource pointer
 308  */
 309 int release_resource(struct resource *old)
 310 {
 311         int retval;
 312
 313         write_lock(&resource_lock);
 314         retval = __release_resource(old, true);
 315         write_unlock(&resource_lock);
 316         return retval;
 317 }
 318
 319 EXPORT_SYMBOL(release_resource);
 320
 321 /**
 322  * Finds the lowest iomem resource that covers part of [start..end].  The
 323  * caller must specify start, end, flags, and desc (which may be
 324  * IORES_DESC_NONE).
 325  *
 326  * If a resource is found, returns 0 and *res is overwritten with the part
 327  * of the resource that's within [start..end]; if none is found, returns
 328  * -1.
 329  *
 330  * This function walks the whole tree and not just first level children
 331  * unless @first_lvl is true.
 332  */
 333 static int find_next_iomem_res(resource_size_t start, resource_size_t end,
 334                                unsigned long flags, unsigned long desc,
 335                                bool first_lvl, struct resource *res)
 336 {
 337         struct resource *p;
 338
 339         if (!res)
 340                 return -EINVAL;
 341
 342         if (start >= end)
 343                 return -EINVAL;
 344
 345         read_lock(&resource_lock);
 346
 347         for (p = iomem_resource.child; p; p = next_resource(p, first_lvl)) {
 348                 if ((p->flags & flags) != flags)
 349                         continue;
 350                 if ((desc != IORES_DESC_NONE) && (desc != p->desc))
 351                         continue;
 352                 if (p->start > end) {
 353                         p = NULL;
 354                         break;
 355                 }
 356                 if ((p->end >= start) && (p->start <= end))
 357                         break;
 358         }
 359
 360         read_unlock(&resource_lock);
 361         if (!p)
 362                 return -1;
 363
 364         /* copy data */
 365         res->start = max(start, p->start);
 366         res->end = min(end, p->end);
 367         res->flags = p->flags;
 368         res->desc = p->desc;
 369         return 0;
 370 }
 371
 372 static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
 373                                  unsigned long flags, unsigned long desc,
 374                                  bool first_lvl, void *arg,
 375                                  int (*func)(struct resource *, void *))
 376 {
 377         struct resource res;
 378         int ret = -1;
 379
 380         while (start < end &&
 381                !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) {
 382                 ret = (*func)(&res, arg);
 383                 if (ret)
 384                         break;
 385
 386                 start = res.end + 1;
 387         }
 388
 389         return ret;
 390 }
 391
 392 /**
 393  * Walks through iomem resources and calls func() with matching resource
 394  * ranges. This walks through whole tree and not just first level children.
 395  * All the memory ranges which overlap start,end and also match flags and
 396  * desc are valid candidates.
 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  *
 403  * NOTE: For a new descriptor search, define a new IORES_DESC in
 404  * <linux/ioport.h> and set it in 'desc' of a target resource entry.
 405  */
 406 int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
 407                 u64 end, void *arg, int (*func)(struct resource *, void *))
 408 {
 409         return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func);
 410 }
 411 EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
 412
 413 /*
 414  * This function calls the @func callback against all memory ranges of type
 415  * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
 416  * Now, this function is only for System RAM, it deals with full ranges and
 417  * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
 418  * ranges.
 419  */
 420 int walk_system_ram_res(u64 start, u64 end, void *arg,
 421                         int (*func)(struct resource *, void *))
 422 {
 423         unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 424
 425         return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true,
 426                                      arg, func);
 427 }
 428
 429 /*
 430  * This function calls the @func callback against all memory ranges, which
 431  * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 432  */
 433 int walk_mem_res(u64 start, u64 end, void *arg,
 434                  int (*func)(struct resource *, void *))
 435 {
 436         unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 437
 438         return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true,
 439                                      arg, func);
 440 }
 441
 442 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 443
 444 /*
 445  * This function calls the @func callback against all memory ranges of type
 446  * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
 447  * It is to be used only for System RAM.
 448  */
 449 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 450                           void *arg, int (*func)(unsigned long, unsigned long, void *))
 451 {
 452         resource_size_t start, end;
 453         unsigned long flags;
 454         struct resource res;
 455         unsigned long pfn, end_pfn;
 456         int ret = -1;
 457
 458         start = (u64) start_pfn << PAGE_SHIFT;
 459         end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 460         flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 461         while (start < end &&
 462                !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
 463                                     true, &res)) {
 464                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 465                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 466                 if (end_pfn > pfn)
 467                         ret = (*func)(pfn, end_pfn - pfn, arg);
 468                 if (ret)
 469                         break;
 470                 start = res.end + 1;
 471         }
 472         return ret;
 473 }
 474
 475 #endif
 476
 477 static 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  */
 486 int __weak page_is_ram(unsigned long pfn)
 487 {
 488         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 489 }
 490 EXPORT_SYMBOL_GPL(page_is_ram);
 491
 492 /**
 493  * region_intersects() - determine intersection of region with known resources
 494  * @start: region start address
 495  * @size: size of region
 496  * @flags: flags of resource (in iomem_resource)
 497  * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
 498  *
 499  * Check if the specified region partially overlaps or fully eclipses a
 500  * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
 501  * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
 502  * return REGION_MIXED if the region overlaps @flags/@desc and another
 503  * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
 504  * and no other defined resource. Note that REGION_INTERSECTS is also
 505  * returned in the case when the specified region overlaps RAM and undefined
 506  * memory holes.
 507  *
 508  * region_intersect() is used by memory remapping functions to ensure
 509  * the user is not remapping RAM and is a vast speed up over walking
 510  * through the resource table page by page.
 511  */
 512 int region_intersects(resource_size_t start, size_t size, unsigned long flags,
 513                       unsigned long desc)
 514 {
 515         resource_size_t end = start + size - 1;
 516         int type = 0; int other = 0;
 517         struct resource *p;
 518
 519         read_lock(&resource_lock);
 520         for (p = iomem_resource.child; p ; p = p->sibling) {
 521                 bool is_type = (((p->flags & flags) == flags) &&
 522                                 ((desc == IORES_DESC_NONE) ||
 523                                  (desc == p->desc)));
 524
 525                 if (start >= p->start && start <= p->end)
 526                         is_type ? type++ : other++;
 527                 if (end >= p->start && end <= p->end)
 528                         is_type ? type++ : other++;
 529                 if (p->start >= start && p->end <= end)
 530                         is_type ? type++ : other++;
 531         }
 532         read_unlock(&resource_lock);
 533
 534         if (other == 0)
 535                 return type ? REGION_INTERSECTS : REGION_DISJOINT;
 536
 537         if (type)
 538                 return REGION_MIXED;
 539
 540         return REGION_DISJOINT;
 541 }
 542 EXPORT_SYMBOL_GPL(region_intersects);
 543
 544 void __weak arch_remove_reservations(struct resource *avail)
 545 {
 546 }
 547
 548 static resource_size_t simple_align_resource(void *data,
 549                                              const struct resource *avail,
 550                                              resource_size_t size,
 551                                              resource_size_t align)
 552 {
 553         return avail->start;
 554 }
 555
 556 static void resource_clip(struct resource *res, resource_size_t min,
 557                           resource_size_t max)
 558 {
 559         if (res->start < min)
 560                 res->start = min;
 561         if (res->end > max)
 562                 res->end = max;
 563 }
 564
 565 /*
 566  * Find empty slot in the resource tree with the given range and
 567  * alignment constraints
 568  */
 569 static int __find_resource(struct resource *root, struct resource *old,
 570                          struct resource *new,
 571                          resource_size_t  size,
 572                          struct resource_constraint *constraint)
 573 {
 574         struct resource *this = root->child;
 575         struct resource tmp = *new, avail, alloc;
 576
 577         tmp.start = root->start;
 578         /*
 579          * Skip past an allocated resource that starts at 0, since the assignment
 580          * of this->start - 1 to tmp->end below would cause an underflow.
 581          */
 582         if (this && this->start == root->start) {
 583                 tmp.start = (this == old) ? old->start : this->end + 1;
 584                 this = this->sibling;
 585         }
 586         for(;;) {
 587                 if (this)
 588                         tmp.end = (this == old) ?  this->end : this->start - 1;
 589                 else
 590                         tmp.end = root->end;
 591
 592                 if (tmp.end < tmp.start)
 593                         goto next;
 594
 595                 resource_clip(&tmp, constraint->min, constraint->max);
 596                 arch_remove_reservations(&tmp);
 597
 598                 /* Check for overflow after ALIGN() */
 599                 avail.start = ALIGN(tmp.start, constraint->align);
 600                 avail.end = tmp.end;
 601                 avail.flags = new->flags & ~IORESOURCE_UNSET;
 602                 if (avail.start >= tmp.start) {
 603                         alloc.flags = avail.flags;
 604                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 605                                         size, constraint->align);
 606                         alloc.end = alloc.start + size - 1;
 607                         if (alloc.start <= alloc.end &&
 608                             resource_contains(&avail, &alloc)) {
 609                                 new->start = alloc.start;
 610                                 new->end = alloc.end;
 611                                 return 0;
 612                         }
 613                 }
 614
 615 next:           if (!this || this->end == root->end)
 616                         break;
 617
 618                 if (this != old)
 619                         tmp.start = this->end + 1;
 620                 this = this->sibling;
 621         }
 622         return -EBUSY;
 623 }
 624
 625 /*
 626  * Find empty slot in the resource tree given range and alignment.
 627  */
 628 static int find_resource(struct resource *root, struct resource *new,
 629                         resource_size_t size,
 630                         struct resource_constraint  *constraint)
 631 {
 632         return  __find_resource(root, NULL, new, size, constraint);
 633 }
 634
 635 /**
 636  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 637  *      The resource will be relocated if the new size cannot be reallocated in the
 638  *      current location.
 639  *
 640  * @root: root resource descriptor
 641  * @old:  resource descriptor desired by caller
 642  * @newsize: new size of the resource descriptor
 643  * @constraint: the size and alignment constraints to be met.
 644  */
 645 static int reallocate_resource(struct resource *root, struct resource *old,
 646                                resource_size_t newsize,
 647                                struct resource_constraint *constraint)
 648 {
 649         int err=0;
 650         struct resource new = *old;
 651         struct resource *conflict;
 652
 653         write_lock(&resource_lock);
 654
 655         if ((err = __find_resource(root, old, &new, newsize, constraint)))
 656                 goto out;
 657
 658         if (resource_contains(&new, old)) {
 659                 old->start = new.start;
 660                 old->end = new.end;
 661                 goto out;
 662         }
 663
 664         if (old->child) {
 665                 err = -EBUSY;
 666                 goto out;
 667         }
 668
 669         if (resource_contains(old, &new)) {
 670                 old->start = new.start;
 671                 old->end = new.end;
 672         } else {
 673                 __release_resource(old, true);
 674                 *old = new;
 675                 conflict = __request_resource(root, old);
 676                 BUG_ON(conflict);
 677         }
 678 out:
 679         write_unlock(&resource_lock);
 680         return err;
 681 }
 682
 683
 684 /**
 685  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 686  *      The resource will be reallocated with a new size if it was already allocated
 687  * @root: root resource descriptor
 688  * @new: resource descriptor desired by caller
 689  * @size: requested resource region size
 690  * @min: minimum boundary to allocate
 691  * @max: maximum boundary to allocate
 692  * @align: alignment requested, in bytes
 693  * @alignf: alignment function, optional, called if not NULL
 694  * @alignf_data: arbitrary data to pass to the @alignf function
 695  */
 696 int allocate_resource(struct resource *root, struct resource *new,
 697                       resource_size_t size, resource_size_t min,
 698                       resource_size_t max, resource_size_t align,
 699                       resource_size_t (*alignf)(void *,
 700                                                 const struct resource *,
 701                                                 resource_size_t,
 702                                                 resource_size_t),
 703                       void *alignf_data)
 704 {
 705         int err;
 706         struct resource_constraint constraint;
 707
 708         if (!alignf)
 709                 alignf = simple_align_resource;
 710
 711         constraint.min = min;
 712         constraint.max = max;
 713         constraint.align = align;
 714         constraint.alignf = alignf;
 715         constraint.alignf_data = alignf_data;
 716
 717         if ( new->parent ) {
 718                 /* resource is already allocated, try reallocating with
 719                    the new constraints */
 720                 return reallocate_resource(root, new, size, &constraint);
 721         }
 722
 723         write_lock(&resource_lock);
 724         err = find_resource(root, new, size, &constraint);
 725         if (err >= 0 && __request_resource(root, new))
 726                 err = -EBUSY;
 727         write_unlock(&resource_lock);
 728         return err;
 729 }
 730
 731 EXPORT_SYMBOL(allocate_resource);
 732
 733 /**
 734  * lookup_resource - find an existing resource by a resource start address
 735  * @root: root resource descriptor
 736  * @start: resource start address
 737  *
 738  * Returns a pointer to the resource if found, NULL otherwise
 739  */
 740 struct resource *lookup_resource(struct resource *root, resource_size_t start)
 741 {
 742         struct resource *res;
 743
 744         read_lock(&resource_lock);
 745         for (res = root->child; res; res = res->sibling) {
 746                 if (res->start == start)
 747                         break;
 748         }
 749         read_unlock(&resource_lock);
 750
 751         return res;
 752 }
 753
 754 /*
 755  * Insert a resource into the resource tree. If successful, return NULL,
 756  * otherwise return the conflicting resource (compare to __request_resource())
 757  */
 758 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 759 {
 760         struct resource *first, *next;
 761
 762         for (;; parent = first) {
 763                 first = __request_resource(parent, new);
 764                 if (!first)
 765                         return first;
 766
 767                 if (first == parent)
 768                         return first;
 769                 if (WARN_ON(first == new))      /* duplicated insertion */
 770                         return first;
 771
 772                 if ((first->start > new->start) || (first->end < new->end))
 773                         break;
 774                 if ((first->start == new->start) && (first->end == new->end))
 775                         break;
 776         }
 777
 778         for (next = first; ; next = next->sibling) {
 779                 /* Partial overlap? Bad, and unfixable */
 780                 if (next->start < new->start || next->end > new->end)
 781                         return next;
 782                 if (!next->sibling)
 783                         break;
 784                 if (next->sibling->start > new->end)
 785                         break;
 786         }
 787
 788         new->parent = parent;
 789         new->sibling = next->sibling;
 790         new->child = first;
 791
 792         next->sibling = NULL;
 793         for (next = first; next; next = next->sibling)
 794                 next->parent = new;
 795
 796         if (parent->child == first) {
 797                 parent->child = new;
 798         } else {
 799                 next = parent->child;
 800                 while (next->sibling != first)
 801                         next = next->sibling;
 802                 next->sibling = new;
 803         }
 804         return NULL;
 805 }
 806
 807 /**
 808  * insert_resource_conflict - Inserts resource in the resource tree
 809  * @parent: parent of the new resource
 810  * @new: new resource to insert
 811  *
 812  * Returns 0 on success, conflict resource if the resource can't be inserted.
 813  *
 814  * This function is equivalent to request_resource_conflict when no conflict
 815  * happens. If a conflict happens, and the conflicting resources
 816  * entirely fit within the range of the new resource, then the new
 817  * resource is inserted and the conflicting resources become children of
 818  * the new resource.
 819  *
 820  * This function is intended for producers of resources, such as FW modules
 821  * and bus drivers.
 822  */
 823 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 824 {
 825         struct resource *conflict;
 826
 827         write_lock(&resource_lock);
 828         conflict = __insert_resource(parent, new);
 829         write_unlock(&resource_lock);
 830         return conflict;
 831 }
 832
 833 /**
 834  * insert_resource - Inserts a resource in the resource tree
 835  * @parent: parent of the new resource
 836  * @new: new resource to insert
 837  *
 838  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 839  *
 840  * This function is intended for producers of resources, such as FW modules
 841  * and bus drivers.
 842  */
 843 int insert_resource(struct resource *parent, struct resource *new)
 844 {
 845         struct resource *conflict;
 846
 847         conflict = insert_resource_conflict(parent, new);
 848         return conflict ? -EBUSY : 0;
 849 }
 850 EXPORT_SYMBOL_GPL(insert_resource);
 851
 852 /**
 853  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 854  * @root: root resource descriptor
 855  * @new: new resource to insert
 856  *
 857  * Insert a resource into the resource tree, possibly expanding it in order
 858  * to make it encompass any conflicting resources.
 859  */
 860 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 861 {
 862         if (new->parent)
 863                 return;
 864
 865         write_lock(&resource_lock);
 866         for (;;) {
 867                 struct resource *conflict;
 868
 869                 conflict = __insert_resource(root, new);
 870                 if (!conflict)
 871                         break;
 872                 if (conflict == root)
 873                         break;
 874
 875                 /* Ok, expand resource to cover the conflict, then try again .. */
 876                 if (conflict->start < new->start)
 877                         new->start = conflict->start;
 878                 if (conflict->end > new->end)
 879                         new->end = conflict->end;
 880
 881                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 882         }
 883         write_unlock(&resource_lock);
 884 }
 885
 886 /**
 887  * remove_resource - Remove a resource in the resource tree
 888  * @old: resource to remove
 889  *
 890  * Returns 0 on success, -EINVAL if the resource is not valid.
 891  *
 892  * This function removes a resource previously inserted by insert_resource()
 893  * or insert_resource_conflict(), and moves the children (if any) up to
 894  * where they were before.  insert_resource() and insert_resource_conflict()
 895  * insert a new resource, and move any conflicting resources down to the
 896  * children of the new resource.
 897  *
 898  * insert_resource(), insert_resource_conflict() and remove_resource() are
 899  * intended for producers of resources, such as FW modules and bus drivers.
 900  */
 901 int remove_resource(struct resource *old)
 902 {
 903         int retval;
 904
 905         write_lock(&resource_lock);
 906         retval = __release_resource(old, false);
 907         write_unlock(&resource_lock);
 908         return retval;
 909 }
 910 EXPORT_SYMBOL_GPL(remove_resource);
 911
 912 static int __adjust_resource(struct resource *res, resource_size_t start,
 913                                 resource_size_t size)
 914 {
 915         struct resource *tmp, *parent = res->parent;
 916         resource_size_t end = start + size - 1;
 917         int result = -EBUSY;
 918
 919         if (!parent)
 920                 goto skip;
 921
 922         if ((start < parent->start) || (end > parent->end))
 923                 goto out;
 924
 925         if (res->sibling && (res->sibling->start <= end))
 926                 goto out;
 927
 928         tmp = parent->child;
 929         if (tmp != res) {
 930                 while (tmp->sibling != res)
 931                         tmp = tmp->sibling;
 932                 if (start <= tmp->end)
 933                         goto out;
 934         }
 935
 936 skip:
 937         for (tmp = res->child; tmp; tmp = tmp->sibling)
 938                 if ((tmp->start < start) || (tmp->end > end))
 939                         goto out;
 940
 941         res->start = start;
 942         res->end = end;
 943         result = 0;
 944
 945  out:
 946         return result;
 947 }
 948
 949 /**
 950  * adjust_resource - modify a resource's start and size
 951  * @res: resource to modify
 952  * @start: new start value
 953  * @size: new size
 954  *
 955  * Given an existing resource, change its start and size to match the
 956  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 957  * Existing children of the resource are assumed to be immutable.
 958  */
 959 int adjust_resource(struct resource *res, resource_size_t start,
 960                     resource_size_t size)
 961 {
 962         int result;
 963
 964         write_lock(&resource_lock);
 965         result = __adjust_resource(res, start, size);
 966         write_unlock(&resource_lock);
 967         return result;
 968 }
 969 EXPORT_SYMBOL(adjust_resource);
 970
 971 static void __init
 972 __reserve_region_with_split(struct resource *root, resource_size_t start,
 973                             resource_size_t end, const char *name)
 974 {
 975         struct resource *parent = root;
 976         struct resource *conflict;
 977         struct resource *res = alloc_resource(GFP_ATOMIC);
 978         struct resource *next_res = NULL;
 979         int type = resource_type(root);
 980
 981         if (!res)
 982                 return;
 983
 984         res->name = name;
 985         res->start = start;
 986         res->end = end;
 987         res->flags = type | IORESOURCE_BUSY;
 988         res->desc = IORES_DESC_NONE;
 989
 990         while (1) {
 991
 992                 conflict = __request_resource(parent, res);
 993                 if (!conflict) {
 994                         if (!next_res)
 995                                 break;
 996                         res = next_res;
 997                         next_res = NULL;
 998                         continue;
 999                 }
1000
1001                 /* conflict covered whole area */
1002                 if (conflict->start <= res->start &&
1003                                 conflict->end >= res->end) {
1004                         free_resource(res);
1005                         WARN_ON(next_res);
1006                         break;
1007                 }
1008
1009                 /* failed, split and try again */
1010                 if (conflict->start > res->start) {
1011                         end = res->end;
1012                         res->end = conflict->start - 1;
1013                         if (conflict->end < end) {
1014                                 next_res = alloc_resource(GFP_ATOMIC);
1015                                 if (!next_res) {
1016                                         free_resource(res);
1017                                         break;
1018                                 }
1019                                 next_res->name = name;
1020                                 next_res->start = conflict->end + 1;
1021                                 next_res->end = end;
1022                                 next_res->flags = type | IORESOURCE_BUSY;
1023                                 next_res->desc = IORES_DESC_NONE;
1024                         }
1025                 } else {
1026                         res->start = conflict->end + 1;
1027                 }
1028         }
1029
1030 }
1031
1032 void __init
1033 reserve_region_with_split(struct resource *root, resource_size_t start,
1034                           resource_size_t end, const char *name)
1035 {
1036         int abort = 0;
1037
1038         write_lock(&resource_lock);
1039         if (root->start > start || root->end < end) {
1040                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
1041                        (unsigned long long)start, (unsigned long long)end,
1042                        root);
1043                 if (start > root->end || end < root->start)
1044                         abort = 1;
1045                 else {
1046                         if (end > root->end)
1047                                 end = root->end;
1048                         if (start < root->start)
1049                                 start = root->start;
1050                         pr_err("fixing request to [0x%llx-0x%llx]\n",
1051                                (unsigned long long)start,
1052                                (unsigned long long)end);
1053                 }
1054                 dump_stack();
1055         }
1056         if (!abort)
1057                 __reserve_region_with_split(root, start, end, name);
1058         write_unlock(&resource_lock);
1059 }
1060
1061 /**
1062  * resource_alignment - calculate resource's alignment
1063  * @res: resource pointer
1064  *
1065  * Returns alignment on success, 0 (invalid alignment) on failure.
1066  */
1067 resource_size_t resource_alignment(struct resource *res)
1068 {
1069         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
1070         case IORESOURCE_SIZEALIGN:
1071                 return resource_size(res);
1072         case IORESOURCE_STARTALIGN:
1073                 return res->start;
1074         default:
1075                 return 0;
1076         }
1077 }
1078
1079 /*
1080  * This is compatibility stuff for IO resources.
1081  *
1082  * Note how this, unlike the above, knows about
1083  * the IO flag meanings (busy etc).
1084  *
1085  * request_region creates a new busy region.
1086  *
1087  * release_region releases a matching busy region.
1088  */
1089
1090 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1091
1092 /**
1093  * __request_region - create a new busy resource region
1094  * @parent: parent resource descriptor
1095  * @start: resource start address
1096  * @n: resource region size
1097  * @name: reserving caller's ID string
1098  * @flags: IO resource flags
1099  */
1100 struct resource * __request_region(struct resource *parent,
1101                                    resource_size_t start, resource_size_t n,
1102                                    const char *name, int flags)
1103 {
1104         DECLARE_WAITQUEUE(wait, current);
1105         struct resource *res = alloc_resource(GFP_KERNEL);
1106
1107         if (!res)
1108                 return NULL;
1109
1110         res->name = name;
1111         res->start = start;
1112         res->end = start + n - 1;
1113
1114         write_lock(&resource_lock);
1115
1116         for (;;) {
1117                 struct resource *conflict;
1118
1119                 res->flags = resource_type(parent) | resource_ext_type(parent);
1120                 res->flags |= IORESOURCE_BUSY | flags;
1121                 res->desc = parent->desc;
1122
1123                 conflict = __request_resource(parent, res);
1124                 if (!conflict)
1125                         break;
1126                 if (conflict != parent) {
1127                         if (!(conflict->flags & IORESOURCE_BUSY)) {
1128                                 parent = conflict;
1129                                 continue;
1130                         }
1131                 }
1132                 if (conflict->flags & flags & IORESOURCE_MUXED) {
1133                         add_wait_queue(&muxed_resource_wait, &wait);
1134                         write_unlock(&resource_lock);
1135                         set_current_state(TASK_UNINTERRUPTIBLE);
1136                         schedule();
1137                         remove_wait_queue(&muxed_resource_wait, &wait);
1138                         write_lock(&resource_lock);
1139                         continue;
1140                 }
1141                 /* Uhhuh, that didn't work out.. */
1142                 free_resource(res);
1143                 res = NULL;
1144                 break;
1145         }
1146         write_unlock(&resource_lock);
1147         return res;
1148 }
1149 EXPORT_SYMBOL(__request_region);
1150
1151 /**
1152  * __release_region - release a previously reserved resource region
1153  * @parent: parent resource descriptor
1154  * @start: resource start address
1155  * @n: resource region size
1156  *
1157  * The described resource region must match a currently busy region.
1158  */
1159 void __release_region(struct resource *parent, resource_size_t start,
1160                       resource_size_t n)
1161 {
1162         struct resource **p;
1163         resource_size_t end;
1164
1165         p = &parent->child;
1166         end = start + n - 1;
1167
1168         write_lock(&resource_lock);
1169
1170         for (;;) {
1171                 struct resource *res = *p;
1172
1173                 if (!res)
1174                         break;
1175                 if (res->start <= start && res->end >= end) {
1176                         if (!(res->flags & IORESOURCE_BUSY)) {
1177                                 p = &res->child;
1178                                 continue;
1179                         }
1180                         if (res->start != start || res->end != end)
1181                                 break;
1182                         *p = res->sibling;
1183                         write_unlock(&resource_lock);
1184                         if (res->flags & IORESOURCE_MUXED)
1185                                 wake_up(&muxed_resource_wait);
1186                         free_resource(res);
1187                         return;
1188                 }
1189                 p = &res->sibling;
1190         }
1191
1192         write_unlock(&resource_lock);
1193
1194         printk(KERN_WARNING "Trying to free nonexistent resource "
1195                 "<%016llx-%016llx>\n", (unsigned long long)start,
1196                 (unsigned long long)end);
1197 }
1198 EXPORT_SYMBOL(__release_region);
1199
1200 #ifdef CONFIG_MEMORY_HOTREMOVE
1201 /**
1202  * release_mem_region_adjustable - release a previously reserved memory region
1203  * @parent: parent resource descriptor
1204  * @start: resource start address
1205  * @size: resource region size
1206  *
1207  * This interface is intended for memory hot-delete.  The requested region
1208  * is released from a currently busy memory resource.  The requested region
1209  * must either match exactly or fit into a single busy resource entry.  In
1210  * the latter case, the remaining resource is adjusted accordingly.
1211  * Existing children of the busy memory resource must be immutable in the
1212  * request.
1213  *
1214  * Note:
1215  * - Additional release conditions, such as overlapping region, can be
1216  *   supported after they are confirmed as valid cases.
1217  * - When a busy memory resource gets split into two entries, the code
1218  *   assumes that all children remain in the lower address entry for
1219  *   simplicity.  Enhance this logic when necessary.
1220  */
1221 int release_mem_region_adjustable(struct resource *parent,
1222                                   resource_size_t start, resource_size_t size)
1223 {
1224         struct resource **p;
1225         struct resource *res;
1226         struct resource *new_res;
1227         resource_size_t end;
1228         int ret = -EINVAL;
1229
1230         end = start + size - 1;
1231         if ((start < parent->start) || (end > parent->end))
1232                 return ret;
1233
1234         /* The alloc_resource() result gets checked later */
1235         new_res = alloc_resource(GFP_KERNEL);
1236
1237         p = &parent->child;
1238         write_lock(&resource_lock);
1239
1240         while ((res = *p)) {
1241                 if (res->start >= end)
1242                         break;
1243
1244                 /* look for the next resource if it does not fit into */
1245                 if (res->start > start || res->end < end) {
1246                         p = &res->sibling;
1247                         continue;
1248                 }
1249
1250                 if (!(res->flags & IORESOURCE_MEM))
1251                         break;
1252
1253                 if (!(res->flags & IORESOURCE_BUSY)) {
1254                         p = &res->child;
1255                         continue;
1256                 }
1257
1258                 /* found the target resource; let's adjust accordingly */
1259                 if (res->start == start && res->end == end) {
1260                         /* free the whole entry */
1261                         *p = res->sibling;
1262                         free_resource(res);
1263                         ret = 0;
1264                 } else if (res->start == start && res->end != end) {
1265                         /* adjust the start */
1266                         ret = __adjust_resource(res, end + 1,
1267                                                 res->end - end);
1268                 } else if (res->start != start && res->end == end) {
1269                         /* adjust the end */
1270                         ret = __adjust_resource(res, res->start,
1271                                                 start - res->start);
1272                 } else {
1273                         /* split into two entries */
1274                         if (!new_res) {
1275                                 ret = -ENOMEM;
1276                                 break;
1277                         }
1278                         new_res->name = res->name;
1279                         new_res->start = end + 1;
1280                         new_res->end = res->end;
1281                         new_res->flags = res->flags;
1282                         new_res->desc = res->desc;
1283                         new_res->parent = res->parent;
1284                         new_res->sibling = res->sibling;
1285                         new_res->child = NULL;
1286
1287                         ret = __adjust_resource(res, res->start,
1288                                                 start - res->start);
1289                         if (ret)
1290                                 break;
1291                         res->sibling = new_res;
1292                         new_res = NULL;
1293                 }
1294
1295                 break;
1296         }
1297
1298         write_unlock(&resource_lock);
1299         free_resource(new_res);
1300         return ret;
1301 }
1302 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1303
1304 /*
1305  * Managed region resource
1306  */
1307 static void devm_resource_release(struct device *dev, void *ptr)
1308 {
1309         struct resource **r = ptr;
1310
1311         release_resource(*r);
1312 }
1313
1314 /**
1315  * devm_request_resource() - request and reserve an I/O or memory resource
1316  * @dev: device for which to request the resource
1317  * @root: root of the resource tree from which to request the resource
1318  * @new: descriptor of the resource to request
1319  *
1320  * This is a device-managed version of request_resource(). There is usually
1321  * no need to release resources requested by this function explicitly since
1322  * that will be taken care of when the device is unbound from its driver.
1323  * If for some reason the resource needs to be released explicitly, because
1324  * of ordering issues for example, drivers must call devm_release_resource()
1325  * rather than the regular release_resource().
1326  *
1327  * When a conflict is detected between any existing resources and the newly
1328  * requested resource, an error message will be printed.
1329  *
1330  * Returns 0 on success or a negative error code on failure.
1331  */
1332 int devm_request_resource(struct device *dev, struct resource *root,
1333                           struct resource *new)
1334 {
1335         struct resource *conflict, **ptr;
1336
1337         ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
1338         if (!ptr)
1339                 return -ENOMEM;
1340
1341         *ptr = new;
1342
1343         conflict = request_resource_conflict(root, new);
1344         if (conflict) {
1345                 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
1346                         new, conflict->name, conflict);
1347                 devres_free(ptr);
1348                 return -EBUSY;
1349         }
1350
1351         devres_add(dev, ptr);
1352         return 0;
1353 }
1354 EXPORT_SYMBOL(devm_request_resource);
1355
1356 static int devm_resource_match(struct device *dev, void *res, void *data)
1357 {
1358         struct resource **ptr = res;
1359
1360         return *ptr == data;
1361 }
1362
1363 /**
1364  * devm_release_resource() - release a previously requested resource
1365  * @dev: device for which to release the resource
1366  * @new: descriptor of the resource to release
1367  *
1368  * Releases a resource previously requested using devm_request_resource().
1369  */
1370 void devm_release_resource(struct device *dev, struct resource *new)
1371 {
1372         WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
1373                                new));
1374 }
1375 EXPORT_SYMBOL(devm_release_resource);
1376
1377 struct region_devres {
1378         struct resource *parent;
1379         resource_size_t start;
1380         resource_size_t n;
1381 };
1382
1383 static void devm_region_release(struct device *dev, void *res)
1384 {
1385         struct region_devres *this = res;
1386
1387         __release_region(this->parent, this->start, this->n);
1388 }
1389
1390 static int devm_region_match(struct device *dev, void *res, void *match_data)
1391 {
1392         struct region_devres *this = res, *match = match_data;
1393
1394         return this->parent == match->parent &&
1395                 this->start == match->start && this->n == match->n;
1396 }
1397
1398 struct resource *
1399 __devm_request_region(struct device *dev, struct resource *parent,
1400                       resource_size_t start, resource_size_t n, const char *name)
1401 {
1402         struct region_devres *dr = NULL;
1403         struct resource *res;
1404
1405         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1406                           GFP_KERNEL);
1407         if (!dr)
1408                 return NULL;
1409
1410         dr->parent = parent;
1411         dr->start = start;
1412         dr->n = n;
1413
1414         res = __request_region(parent, start, n, name, 0);
1415         if (res)
1416                 devres_add(dev, dr);
1417         else
1418                 devres_free(dr);
1419
1420         return res;
1421 }
1422 EXPORT_SYMBOL(__devm_request_region);
1423
1424 void __devm_release_region(struct device *dev, struct resource *parent,
1425                            resource_size_t start, resource_size_t n)
1426 {
1427         struct region_devres match_data = { parent, start, n };
1428
1429         __release_region(parent, start, n);
1430         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1431                                &match_data));
1432 }
1433 EXPORT_SYMBOL(__devm_release_region);
1434
1435 /*
1436  * Reserve I/O ports or memory based on "reserve=" kernel parameter.
1437  */
1438 #define MAXRESERVE 4
1439 static int __init reserve_setup(char *str)
1440 {
1441         static int reserved;
1442         static struct resource reserve[MAXRESERVE];
1443
1444         for (;;) {
1445                 unsigned int io_start, io_num;
1446                 int x = reserved;
1447                 struct resource *parent;
1448
1449                 if (get_option(&str, &io_start) != 2)
1450                         break;
1451                 if (get_option(&str, &io_num) == 0)
1452                         break;
1453                 if (x < MAXRESERVE) {
1454                         struct resource *res = reserve + x;
1455
1456                         /*
1457                          * If the region starts below 0x10000, we assume it's
1458                          * I/O port space; otherwise assume it's memory.
1459                          */
1460                         if (io_start < 0x10000) {
1461                                 res->flags = IORESOURCE_IO;
1462                                 parent = &ioport_resource;
1463                         } else {
1464                                 res->flags = IORESOURCE_MEM;
1465                                 parent = &iomem_resource;
1466                         }
1467                         res->name = "reserved";
1468                         res->start = io_start;
1469                         res->end = io_start + io_num - 1;
1470                         res->flags |= IORESOURCE_BUSY;
1471                         res->desc = IORES_DESC_NONE;
1472                         res->child = NULL;
1473                         if (request_resource(parent, res) == 0)
1474                                 reserved = x+1;
1475                 }
1476         }
1477         return 1;
1478 }
1479 __setup("reserve=", reserve_setup);
1480
1481 /*
1482  * Check if the requested addr and size spans more than any slot in the
1483  * iomem resource tree.
1484  */
1485 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1486 {
1487         struct resource *p = &iomem_resource;
1488         int err = 0;
1489         loff_t l;
1490
1491         read_lock(&resource_lock);
1492         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1493                 /*
1494                  * We can probably skip the resources without
1495                  * IORESOURCE_IO attribute?
1496                  */
1497                 if (p->start >= addr + size)
1498                         continue;
1499                 if (p->end < addr)
1500                         continue;
1501                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1502                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1503                         continue;
1504                 /*
1505                  * if a resource is "BUSY", it's not a hardware resource
1506                  * but a driver mapping of such a resource; we don't want
1507                  * to warn for those; some drivers legitimately map only
1508                  * partial hardware resources. (example: vesafb)
1509                  */
1510                 if (p->flags & IORESOURCE_BUSY)
1511                         continue;
1512
1513                 printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1514                        (unsigned long long)addr,
1515                        (unsigned long long)(addr + size - 1),
1516                        p->name, p);
1517                 err = -1;
1518                 break;
1519         }
1520         read_unlock(&resource_lock);
1521
1522         return err;
1523 }
1524
1525 #ifdef CONFIG_STRICT_DEVMEM
1526 static int strict_iomem_checks = 1;
1527 #else
1528 static int strict_iomem_checks;
1529 #endif
1530
1531 /*
1532  * check if an address is reserved in the iomem resource tree
1533  * returns true if reserved, false if not reserved.
1534  */
1535 bool iomem_is_exclusive(u64 addr)
1536 {
1537         struct resource *p = &iomem_resource;
1538         bool err = false;
1539         loff_t l;
1540         int size = PAGE_SIZE;
1541
1542         if (!strict_iomem_checks)
1543                 return false;
1544
1545         addr = addr & PAGE_MASK;
1546
1547         read_lock(&resource_lock);
1548         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1549                 /*
1550                  * We can probably skip the resources without
1551                  * IORESOURCE_IO attribute?
1552                  */
1553                 if (p->start >= addr + size)
1554                         break;
1555                 if (p->end < addr)
1556                         continue;
1557                 /*
1558                  * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
1559                  * or CONFIG_IO_STRICT_DEVMEM is enabled and the
1560                  * resource is busy.
1561                  */
1562                 if ((p->flags & IORESOURCE_BUSY) == 0)
1563                         continue;
1564                 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
1565                                 || p->flags & IORESOURCE_EXCLUSIVE) {
1566                         err = true;
1567                         break;
1568                 }
1569         }
1570         read_unlock(&resource_lock);
1571
1572         return err;
1573 }
1574
1575 struct resource_entry *resource_list_create_entry(struct resource *res,
1576                                                   size_t extra_size)
1577 {
1578         struct resource_entry *entry;
1579
1580         entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
1581         if (entry) {
1582                 INIT_LIST_HEAD(&entry->node);
1583                 entry->res = res ? res : &entry->__res;
1584         }
1585
1586         return entry;
1587 }
1588 EXPORT_SYMBOL(resource_list_create_entry);
1589
1590 void resource_list_free(struct list_head *head)
1591 {
1592         struct resource_entry *entry, *tmp;
1593
1594         list_for_each_entry_safe(entry, tmp, head, node)
1595                 resource_list_destroy_entry(entry);
1596 }
1597 EXPORT_SYMBOL(resource_list_free);
1598
1599 static int __init strict_iomem(char *str)
1600 {
1601         if (strstr(str, "relaxed"))
1602                 strict_iomem_checks = 0;
1603         if (strstr(str, "strict"))
1604                 strict_iomem_checks = 1;
1605         return 1;
1606 }
1607
1608 __setup("iomem=", strict_iomem);