LCOV - code coverage report
Current view: top level - kernel - resource.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 35 564 6.2 %
Date: 2023-04-06 08:38:28 Functions: 5 60 8.3 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0-only
       2             : /*
       3             :  *      linux/kernel/resource.c
       4             :  *
       5             :  * Copyright (C) 1999   Linus Torvalds
       6             :  * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
       7             :  *
       8             :  * Arbitrary resource management.
       9             :  */
      10             : 
      11             : #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      12             : 
      13             : #include <linux/export.h>
      14             : #include <linux/errno.h>
      15             : #include <linux/ioport.h>
      16             : #include <linux/init.h>
      17             : #include <linux/slab.h>
      18             : #include <linux/spinlock.h>
      19             : #include <linux/fs.h>
      20             : #include <linux/proc_fs.h>
      21             : #include <linux/pseudo_fs.h>
      22             : #include <linux/sched.h>
      23             : #include <linux/seq_file.h>
      24             : #include <linux/device.h>
      25             : #include <linux/pfn.h>
      26             : #include <linux/mm.h>
      27             : #include <linux/mount.h>
      28             : #include <linux/resource_ext.h>
      29             : #include <uapi/linux/magic.h>
      30             : #include <asm/io.h>
      31             : 
      32             : 
      33             : struct resource ioport_resource = {
      34             :         .name   = "PCI IO",
      35             :         .start  = 0,
      36             :         .end    = IO_SPACE_LIMIT,
      37             :         .flags  = IORESOURCE_IO,
      38             : };
      39             : EXPORT_SYMBOL(ioport_resource);
      40             : 
      41             : struct resource iomem_resource = {
      42             :         .name   = "PCI mem",
      43             :         .start  = 0,
      44             :         .end    = -1,
      45             :         .flags  = IORESOURCE_MEM,
      46             : };
      47             : EXPORT_SYMBOL(iomem_resource);
      48             : 
      49             : /* constraints to be met while allocating resources */
      50             : struct 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             : 
      57             : static DEFINE_RWLOCK(resource_lock);
      58             : 
      59             : static struct resource *next_resource(struct resource *p)
      60             : {
      61           0 :         if (p->child)
      62             :                 return p->child;
      63           0 :         while (!p->sibling && p->parent)
      64             :                 p = p->parent;
      65             :         return p->sibling;
      66             : }
      67             : 
      68             : static struct resource *next_resource_skip_children(struct resource *p)
      69             : {
      70           0 :         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             : 
      80           0 : static void *r_next(struct seq_file *m, void *v, loff_t *pos)
      81             : {
      82           0 :         struct resource *p = v;
      83           0 :         (*pos)++;
      84           0 :         return (void *)next_resource(p);
      85             : }
      86             : 
      87             : #ifdef CONFIG_PROC_FS
      88             : 
      89             : enum { MAX_IORES_LEVEL = 5 };
      90             : 
      91           0 : static void *r_start(struct seq_file *m, loff_t *pos)
      92             :         __acquires(resource_lock)
      93             : {
      94           0 :         struct resource *p = pde_data(file_inode(m->file));
      95           0 :         loff_t l = 0;
      96           0 :         read_lock(&resource_lock);
      97           0 :         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
      98             :                 ;
      99           0 :         return p;
     100             : }
     101             : 
     102           0 : static void r_stop(struct seq_file *m, void *v)
     103             :         __releases(resource_lock)
     104             : {
     105           0 :         read_unlock(&resource_lock);
     106           0 : }
     107             : 
     108           0 : static int r_show(struct seq_file *m, void *v)
     109             : {
     110           0 :         struct resource *root = pde_data(file_inode(m->file));
     111           0 :         struct resource *r = v, *p;
     112             :         unsigned long long start, end;
     113           0 :         int width = root->end < 0x10000 ? 4 : 8;
     114             :         int depth;
     115             : 
     116           0 :         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
     117           0 :                 if (p->parent == root)
     118             :                         break;
     119             : 
     120           0 :         if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
     121           0 :                 start = r->start;
     122           0 :                 end = r->end;
     123             :         } else {
     124             :                 start = end = 0;
     125             :         }
     126             : 
     127           0 :         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
     128             :                         depth * 2, "",
     129             :                         width, start,
     130             :                         width, end,
     131           0 :                         r->name ? r->name : "<BAD>");
     132           0 :         return 0;
     133             : }
     134             : 
     135             : static const struct seq_operations resource_op = {
     136             :         .start  = r_start,
     137             :         .next   = r_next,
     138             :         .stop   = r_stop,
     139             :         .show   = r_show,
     140             : };
     141             : 
     142           1 : static int __init ioresources_init(void)
     143             : {
     144           1 :         proc_create_seq_data("ioports", 0, NULL, &resource_op,
     145             :                         &ioport_resource);
     146           1 :         proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
     147           1 :         return 0;
     148             : }
     149             : __initcall(ioresources_init);
     150             : 
     151             : #endif /* CONFIG_PROC_FS */
     152             : 
     153           0 : static 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           0 :         if (res && PageSlab(virt_to_head_page(res)))
     162           0 :                 kfree(res);
     163           0 : }
     164             : 
     165             : static struct resource *alloc_resource(gfp_t flags)
     166             : {
     167           0 :         return kzalloc(sizeof(struct resource), flags);
     168             : }
     169             : 
     170             : /* Return the conflict entry if you can't request it */
     171           3 : static struct resource * __request_resource(struct resource *root, struct resource *new)
     172             : {
     173           3 :         resource_size_t start = new->start;
     174           3 :         resource_size_t end = new->end;
     175             :         struct resource *tmp, **p;
     176             : 
     177           3 :         if (end < start)
     178             :                 return root;
     179           3 :         if (start < root->start)
     180             :                 return root;
     181           3 :         if (end > root->end)
     182             :                 return root;
     183           3 :         p = &root->child;
     184             :         for (;;) {
     185           5 :                 tmp = *p;
     186           4 :                 if (!tmp || tmp->start > end) {
     187           3 :                         new->sibling = tmp;
     188           3 :                         *p = new;
     189           3 :                         new->parent = root;
     190           3 :                         return NULL;
     191             :                 }
     192           1 :                 p = &tmp->sibling;
     193           1 :                 if (tmp->end < start)
     194           1 :                         continue;
     195             :                 return tmp;
     196             :         }
     197             : }
     198             : 
     199           0 : static int __release_resource(struct resource *old, bool release_child)
     200             : {
     201             :         struct resource *tmp, **p, *chd;
     202             : 
     203           0 :         p = &old->parent->child;
     204             :         for (;;) {
     205           0 :                 tmp = *p;
     206           0 :                 if (!tmp)
     207             :                         break;
     208           0 :                 if (tmp == old) {
     209           0 :                         if (release_child || !(tmp->child)) {
     210           0 :                                 *p = tmp->sibling;
     211             :                         } else {
     212             :                                 for (chd = tmp->child;; chd = chd->sibling) {
     213           0 :                                         chd->parent = tmp->parent;
     214           0 :                                         if (!(chd->sibling))
     215             :                                                 break;
     216             :                                 }
     217           0 :                                 *p = tmp->child;
     218           0 :                                 chd->sibling = tmp->sibling;
     219             :                         }
     220           0 :                         old->parent = NULL;
     221           0 :                         return 0;
     222             :                 }
     223           0 :                 p = &tmp->sibling;
     224             :         }
     225             :         return -EINVAL;
     226             : }
     227             : 
     228           0 : static void __release_child_resources(struct resource *r)
     229             : {
     230             :         struct resource *tmp, *p;
     231             :         resource_size_t size;
     232             : 
     233           0 :         p = r->child;
     234           0 :         r->child = NULL;
     235           0 :         while (p) {
     236           0 :                 tmp = p;
     237           0 :                 p = p->sibling;
     238             : 
     239           0 :                 tmp->parent = NULL;
     240           0 :                 tmp->sibling = NULL;
     241           0 :                 __release_child_resources(tmp);
     242             : 
     243           0 :                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
     244             :                 /* need to restore size, and keep flags */
     245           0 :                 size = resource_size(tmp);
     246           0 :                 tmp->start = 0;
     247           0 :                 tmp->end = size - 1;
     248             :         }
     249           0 : }
     250             : 
     251           0 : void release_child_resources(struct resource *r)
     252             : {
     253           0 :         write_lock(&resource_lock);
     254           0 :         __release_child_resources(r);
     255           0 :         write_unlock(&resource_lock);
     256           0 : }
     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             :  */
     265           0 : struct resource *request_resource_conflict(struct resource *root, struct resource *new)
     266             : {
     267             :         struct resource *conflict;
     268             : 
     269           3 :         write_lock(&resource_lock);
     270           3 :         conflict = __request_resource(root, new);
     271           3 :         write_unlock(&resource_lock);
     272           0 :         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             :  */
     282           3 : int request_resource(struct resource *root, struct resource *new)
     283             : {
     284             :         struct resource *conflict;
     285             : 
     286           3 :         conflict = request_resource_conflict(root, new);
     287           3 :         return conflict ? -EBUSY : 0;
     288             : }
     289             : 
     290             : EXPORT_SYMBOL(request_resource);
     291             : 
     292             : /**
     293             :  * release_resource - release a previously reserved resource
     294             :  * @old: resource pointer
     295             :  */
     296           0 : int release_resource(struct resource *old)
     297             : {
     298             :         int retval;
     299             : 
     300           0 :         write_lock(&resource_lock);
     301           0 :         retval = __release_resource(old, true);
     302           0 :         write_unlock(&resource_lock);
     303           0 :         return retval;
     304             : }
     305             : 
     306             : EXPORT_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             :  */
     325           0 : static 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           0 :         if (!res)
     332             :                 return -EINVAL;
     333             : 
     334           0 :         if (start >= end)
     335             :                 return -EINVAL;
     336             : 
     337           0 :         read_lock(&resource_lock);
     338             : 
     339           0 :         for (p = iomem_resource.child; p; p = next_resource(p)) {
     340             :                 /* If we passed the resource we are looking for, stop */
     341           0 :                 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           0 :                 if (p->end < start)
     348           0 :                         continue;
     349             : 
     350           0 :                 if ((p->flags & flags) != flags)
     351           0 :                         continue;
     352           0 :                 if ((desc != IORES_DESC_NONE) && (desc != p->desc))
     353           0 :                         continue;
     354             : 
     355             :                 /* Found a match, break */
     356             :                 break;
     357             :         }
     358             : 
     359           0 :         if (p) {
     360             :                 /* copy data */
     361           0 :                 *res = (struct resource) {
     362           0 :                         .start = max(start, p->start),
     363           0 :                         .end = min(end, p->end),
     364           0 :                         .flags = p->flags,
     365           0 :                         .desc = p->desc,
     366           0 :                         .parent = p->parent,
     367             :                 };
     368             :         }
     369             : 
     370           0 :         read_unlock(&resource_lock);
     371           0 :         return p ? 0 : -ENODEV;
     372             : }
     373             : 
     374           0 : static 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           0 :         int ret = -EINVAL;
     381             : 
     382           0 :         while (start < end &&
     383           0 :                !find_next_iomem_res(start, end, flags, desc, &res)) {
     384           0 :                 ret = (*func)(&res, arg);
     385           0 :                 if (ret)
     386             :                         break;
     387             : 
     388           0 :                 start = res.end + 1;
     389             :         }
     390             : 
     391           0 :         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             :  */
     411           0 : int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
     412             :                 u64 end, void *arg, int (*func)(struct resource *, void *))
     413             : {
     414           0 :         return __walk_iomem_res_desc(start, end, flags, desc, arg, func);
     415             : }
     416             : EXPORT_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             :  */
     425           0 : int walk_system_ram_res(u64 start, u64 end, void *arg,
     426             :                         int (*func)(struct resource *, void *))
     427             : {
     428           0 :         unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
     429             : 
     430           0 :         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             :  */
     438           0 : int walk_mem_res(u64 start, u64 end, void *arg,
     439             :                  int (*func)(struct resource *, void *))
     440             : {
     441           0 :         unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
     442             : 
     443           0 :         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             :  */
     452           0 : int 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           0 :         int ret = -EINVAL;
     460             : 
     461           0 :         start = (u64) start_pfn << PAGE_SHIFT;
     462           0 :         end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
     463           0 :         flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
     464           0 :         while (start < end &&
     465           0 :                !find_next_iomem_res(start, end, flags, IORES_DESC_NONE, &res)) {
     466           0 :                 pfn = PFN_UP(res.start);
     467           0 :                 end_pfn = PFN_DOWN(res.end + 1);
     468           0 :                 if (end_pfn > pfn)
     469           0 :                         ret = (*func)(pfn, end_pfn - pfn, arg);
     470           0 :                 if (ret)
     471             :                         break;
     472           0 :                 start = res.end + 1;
     473             :         }
     474           0 :         return ret;
     475             : }
     476             : 
     477           0 : static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
     478             : {
     479           0 :         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           0 : int __weak page_is_ram(unsigned long pfn)
     487             : {
     488           0 :         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
     489             : }
     490             : EXPORT_SYMBOL_GPL(page_is_ram);
     491             : 
     492           0 : static 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           0 :         int type = 0; int other = 0;
     498             :         struct resource *p;
     499             : 
     500           0 :         res.start = start;
     501           0 :         res.end = start + size - 1;
     502             : 
     503           0 :         for (p = parent->child; p ; p = p->sibling) {
     504           0 :                 bool is_type = (((p->flags & flags) == flags) &&
     505           0 :                                 ((desc == IORES_DESC_NONE) ||
     506           0 :                                  (desc == p->desc)));
     507             : 
     508           0 :                 if (resource_overlaps(p, &res))
     509           0 :                         is_type ? type++ : other++;
     510             :         }
     511             : 
     512           0 :         if (type == 0)
     513             :                 return REGION_DISJOINT;
     514             : 
     515           0 :         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             :  */
     541           0 : int region_intersects(resource_size_t start, size_t size, unsigned long flags,
     542             :                       unsigned long desc)
     543             : {
     544             :         int ret;
     545             : 
     546           0 :         read_lock(&resource_lock);
     547           0 :         ret = __region_intersects(&iomem_resource, start, size, flags, desc);
     548           0 :         read_unlock(&resource_lock);
     549             : 
     550           0 :         return ret;
     551             : }
     552             : EXPORT_SYMBOL_GPL(region_intersects);
     553             : 
     554           0 : void __weak arch_remove_reservations(struct resource *avail)
     555             : {
     556           0 : }
     557             : 
     558           0 : static 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           0 :         return avail->start;
     564             : }
     565             : 
     566             : static void resource_clip(struct resource *res, resource_size_t min,
     567             :                           resource_size_t max)
     568             : {
     569           0 :         if (res->start < min)
     570           0 :                 res->start = min;
     571           0 :         if (res->end > max)
     572           0 :                 res->end = max;
     573             : }
     574             : 
     575             : /*
     576             :  * Find empty slot in the resource tree with the given range and
     577             :  * alignment constraints
     578             :  */
     579           0 : static 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           0 :         struct resource *this = root->child;
     585           0 :         struct resource tmp = *new, avail, alloc;
     586             : 
     587           0 :         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           0 :         if (this && this->start == root->start) {
     593           0 :                 tmp.start = (this == old) ? old->start : this->end + 1;
     594           0 :                 this = this->sibling;
     595             :         }
     596             :         for(;;) {
     597           0 :                 if (this)
     598           0 :                         tmp.end = (this == old) ?  this->end : this->start - 1;
     599             :                 else
     600           0 :                         tmp.end = root->end;
     601             : 
     602           0 :                 if (tmp.end < tmp.start)
     603             :                         goto next;
     604             : 
     605           0 :                 resource_clip(&tmp, constraint->min, constraint->max);
     606           0 :                 arch_remove_reservations(&tmp);
     607             : 
     608             :                 /* Check for overflow after ALIGN() */
     609           0 :                 avail.start = ALIGN(tmp.start, constraint->align);
     610           0 :                 avail.end = tmp.end;
     611           0 :                 avail.flags = new->flags & ~IORESOURCE_UNSET;
     612           0 :                 if (avail.start >= tmp.start) {
     613           0 :                         alloc.flags = avail.flags;
     614           0 :                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
     615             :                                         size, constraint->align);
     616           0 :                         alloc.end = alloc.start + size - 1;
     617           0 :                         if (alloc.start <= alloc.end &&
     618           0 :                             resource_contains(&avail, &alloc)) {
     619           0 :                                 new->start = alloc.start;
     620           0 :                                 new->end = alloc.end;
     621           0 :                                 return 0;
     622             :                         }
     623             :                 }
     624             : 
     625           0 : next:           if (!this || this->end == root->end)
     626             :                         break;
     627             : 
     628           0 :                 if (this != old)
     629           0 :                         tmp.start = this->end + 1;
     630           0 :                 this = this->sibling;
     631             :         }
     632             :         return -EBUSY;
     633             : }
     634             : 
     635             : /*
     636             :  * Find empty slot in the resource tree given range and alignment.
     637             :  */
     638             : static int find_resource(struct resource *root, struct resource *new,
     639             :                         resource_size_t size,
     640             :                         struct resource_constraint  *constraint)
     641             : {
     642           0 :         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             :  */
     655           0 : static int reallocate_resource(struct resource *root, struct resource *old,
     656             :                                resource_size_t newsize,
     657             :                                struct resource_constraint *constraint)
     658             : {
     659           0 :         int err=0;
     660           0 :         struct resource new = *old;
     661             :         struct resource *conflict;
     662             : 
     663           0 :         write_lock(&resource_lock);
     664             : 
     665           0 :         if ((err = __find_resource(root, old, &new, newsize, constraint)))
     666             :                 goto out;
     667             : 
     668           0 :         if (resource_contains(&new, old)) {
     669           0 :                 old->start = new.start;
     670           0 :                 old->end = new.end;
     671           0 :                 goto out;
     672             :         }
     673             : 
     674           0 :         if (old->child) {
     675             :                 err = -EBUSY;
     676             :                 goto out;
     677             :         }
     678             : 
     679           0 :         if (resource_contains(old, &new)) {
     680           0 :                 old->start = new.start;
     681           0 :                 old->end = new.end;
     682             :         } else {
     683           0 :                 __release_resource(old, true);
     684           0 :                 *old = new;
     685           0 :                 conflict = __request_resource(root, old);
     686           0 :                 BUG_ON(conflict);
     687             :         }
     688             : out:
     689           0 :         write_unlock(&resource_lock);
     690           0 :         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             :  */
     706           0 : int 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           0 :         if (!alignf)
     719           0 :                 alignf = simple_align_resource;
     720             : 
     721           0 :         constraint.min = min;
     722           0 :         constraint.max = max;
     723           0 :         constraint.align = align;
     724           0 :         constraint.alignf = alignf;
     725           0 :         constraint.alignf_data = alignf_data;
     726             : 
     727           0 :         if ( new->parent ) {
     728             :                 /* resource is already allocated, try reallocating with
     729             :                    the new constraints */
     730           0 :                 return reallocate_resource(root, new, size, &constraint);
     731             :         }
     732             : 
     733           0 :         write_lock(&resource_lock);
     734           0 :         err = find_resource(root, new, size, &constraint);
     735           0 :         if (err >= 0 && __request_resource(root, new))
     736           0 :                 err = -EBUSY;
     737           0 :         write_unlock(&resource_lock);
     738           0 :         return err;
     739             : }
     740             : 
     741             : EXPORT_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             :  */
     750           0 : struct resource *lookup_resource(struct resource *root, resource_size_t start)
     751             : {
     752             :         struct resource *res;
     753             : 
     754           0 :         read_lock(&resource_lock);
     755           0 :         for (res = root->child; res; res = res->sibling) {
     756           0 :                 if (res->start == start)
     757             :                         break;
     758             :         }
     759           0 :         read_unlock(&resource_lock);
     760             : 
     761           0 :         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             :  */
     768           0 : static struct resource * __insert_resource(struct resource *parent, struct resource *new)
     769             : {
     770             :         struct resource *first, *next;
     771             : 
     772             :         for (;; parent = first) {
     773           0 :                 first = __request_resource(parent, new);
     774           0 :                 if (!first)
     775             :                         return first;
     776             : 
     777           0 :                 if (first == parent)
     778             :                         return first;
     779           0 :                 if (WARN_ON(first == new))      /* duplicated insertion */
     780             :                         return first;
     781             : 
     782           0 :                 if ((first->start > new->start) || (first->end < new->end))
     783             :                         break;
     784           0 :                 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           0 :                 if (next->start < new->start || next->end > new->end)
     791             :                         return next;
     792           0 :                 if (!next->sibling)
     793             :                         break;
     794           0 :                 if (next->sibling->start > new->end)
     795             :                         break;
     796             :         }
     797             : 
     798           0 :         new->parent = parent;
     799           0 :         new->sibling = next->sibling;
     800           0 :         new->child = first;
     801             : 
     802           0 :         next->sibling = NULL;
     803           0 :         for (next = first; next; next = next->sibling)
     804           0 :                 next->parent = new;
     805             : 
     806           0 :         if (parent->child == first) {
     807           0 :                 parent->child = new;
     808             :         } else {
     809             :                 next = parent->child;
     810           0 :                 while (next->sibling != first)
     811             :                         next = next->sibling;
     812           0 :                 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             :  */
     833           0 : struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
     834             : {
     835             :         struct resource *conflict;
     836             : 
     837           0 :         write_lock(&resource_lock);
     838           0 :         conflict = __insert_resource(parent, new);
     839           0 :         write_unlock(&resource_lock);
     840           0 :         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             :  */
     853           0 : int insert_resource(struct resource *parent, struct resource *new)
     854             : {
     855             :         struct resource *conflict;
     856             : 
     857           0 :         conflict = insert_resource_conflict(parent, new);
     858           0 :         return conflict ? -EBUSY : 0;
     859             : }
     860             : EXPORT_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             :  */
     870           0 : void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
     871             : {
     872           0 :         if (new->parent)
     873             :                 return;
     874             : 
     875           0 :         write_lock(&resource_lock);
     876           0 :         for (;;) {
     877             :                 struct resource *conflict;
     878             : 
     879           0 :                 conflict = __insert_resource(root, new);
     880           0 :                 if (!conflict)
     881             :                         break;
     882           0 :                 if (conflict == root)
     883             :                         break;
     884             : 
     885             :                 /* Ok, expand resource to cover the conflict, then try again .. */
     886           0 :                 if (conflict->start < new->start)
     887           0 :                         new->start = conflict->start;
     888           0 :                 if (conflict->end > new->end)
     889           0 :                         new->end = conflict->end;
     890             : 
     891           0 :                 pr_info("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
     892             :         }
     893           0 :         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             :  */
     901             : EXPORT_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             :  */
     918           0 : int remove_resource(struct resource *old)
     919             : {
     920             :         int retval;
     921             : 
     922           0 :         write_lock(&resource_lock);
     923           0 :         retval = __release_resource(old, false);
     924           0 :         write_unlock(&resource_lock);
     925           0 :         return retval;
     926             : }
     927             : EXPORT_SYMBOL_GPL(remove_resource);
     928             : 
     929           0 : static int __adjust_resource(struct resource *res, resource_size_t start,
     930             :                                 resource_size_t size)
     931             : {
     932           0 :         struct resource *tmp, *parent = res->parent;
     933           0 :         resource_size_t end = start + size - 1;
     934           0 :         int result = -EBUSY;
     935             : 
     936           0 :         if (!parent)
     937             :                 goto skip;
     938             : 
     939           0 :         if ((start < parent->start) || (end > parent->end))
     940             :                 goto out;
     941             : 
     942           0 :         if (res->sibling && (res->sibling->start <= end))
     943             :                 goto out;
     944             : 
     945           0 :         tmp = parent->child;
     946           0 :         if (tmp != res) {
     947           0 :                 while (tmp->sibling != res)
     948             :                         tmp = tmp->sibling;
     949           0 :                 if (start <= tmp->end)
     950             :                         goto out;
     951             :         }
     952             : 
     953             : skip:
     954           0 :         for (tmp = res->child; tmp; tmp = tmp->sibling)
     955           0 :                 if ((tmp->start < start) || (tmp->end > end))
     956             :                         goto out;
     957             : 
     958           0 :         res->start = start;
     959           0 :         res->end = end;
     960           0 :         result = 0;
     961             : 
     962             :  out:
     963           0 :         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             :  */
     976           0 : int adjust_resource(struct resource *res, resource_size_t start,
     977             :                     resource_size_t size)
     978             : {
     979             :         int result;
     980             : 
     981           0 :         write_lock(&resource_lock);
     982           0 :         result = __adjust_resource(res, start, size);
     983           0 :         write_unlock(&resource_lock);
     984           0 :         return result;
     985             : }
     986             : EXPORT_SYMBOL(adjust_resource);
     987             : 
     988             : static void __init
     989           0 : __reserve_region_with_split(struct resource *root, resource_size_t start,
     990             :                             resource_size_t end, const char *name)
     991             : {
     992           0 :         struct resource *parent = root;
     993             :         struct resource *conflict;
     994           0 :         struct resource *res = alloc_resource(GFP_ATOMIC);
     995           0 :         struct resource *next_res = NULL;
     996           0 :         int type = resource_type(root);
     997             : 
     998           0 :         if (!res)
     999             :                 return;
    1000             : 
    1001           0 :         res->name = name;
    1002           0 :         res->start = start;
    1003           0 :         res->end = end;
    1004           0 :         res->flags = type | IORESOURCE_BUSY;
    1005           0 :         res->desc = IORES_DESC_NONE;
    1006             : 
    1007             :         while (1) {
    1008             : 
    1009           0 :                 conflict = __request_resource(parent, res);
    1010           0 :                 if (!conflict) {
    1011           0 :                         if (!next_res)
    1012             :                                 break;
    1013           0 :                         res = next_res;
    1014           0 :                         next_res = NULL;
    1015           0 :                         continue;
    1016             :                 }
    1017             : 
    1018             :                 /* conflict covered whole area */
    1019           0 :                 if (conflict->start <= res->start &&
    1020           0 :                                 conflict->end >= res->end) {
    1021           0 :                         free_resource(res);
    1022           0 :                         WARN_ON(next_res);
    1023             :                         break;
    1024             :                 }
    1025             : 
    1026             :                 /* failed, split and try again */
    1027           0 :                 if (conflict->start > res->start) {
    1028           0 :                         end = res->end;
    1029           0 :                         res->end = conflict->start - 1;
    1030           0 :                         if (conflict->end < end) {
    1031           0 :                                 next_res = alloc_resource(GFP_ATOMIC);
    1032           0 :                                 if (!next_res) {
    1033           0 :                                         free_resource(res);
    1034           0 :                                         break;
    1035             :                                 }
    1036           0 :                                 next_res->name = name;
    1037           0 :                                 next_res->start = conflict->end + 1;
    1038           0 :                                 next_res->end = end;
    1039           0 :                                 next_res->flags = type | IORESOURCE_BUSY;
    1040           0 :                                 next_res->desc = IORES_DESC_NONE;
    1041             :                         }
    1042             :                 } else {
    1043           0 :                         res->start = conflict->end + 1;
    1044             :                 }
    1045             :         }
    1046             : 
    1047             : }
    1048             : 
    1049             : void __init
    1050           0 : reserve_region_with_split(struct resource *root, resource_size_t start,
    1051             :                           resource_size_t end, const char *name)
    1052             : {
    1053           0 :         int abort = 0;
    1054             : 
    1055           0 :         write_lock(&resource_lock);
    1056           0 :         if (root->start > start || root->end < end) {
    1057           0 :                 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           0 :                 if (start > root->end || end < root->start)
    1061             :                         abort = 1;
    1062             :                 else {
    1063           0 :                         if (end > root->end)
    1064           0 :                                 end = root->end;
    1065           0 :                         if (start < root->start)
    1066           0 :                                 start = root->start;
    1067           0 :                         pr_err("fixing request to [0x%llx-0x%llx]\n",
    1068             :                                (unsigned long long)start,
    1069             :                                (unsigned long long)end);
    1070             :                 }
    1071           0 :                 dump_stack();
    1072             :         }
    1073           0 :         if (!abort)
    1074           0 :                 __reserve_region_with_split(root, start, end, name);
    1075           0 :         write_unlock(&resource_lock);
    1076           0 : }
    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             :  */
    1084           0 : resource_size_t resource_alignment(struct resource *res)
    1085             : {
    1086           0 :         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
    1087             :         case IORESOURCE_SIZEALIGN:
    1088           0 :                 return resource_size(res);
    1089             :         case IORESOURCE_STARTALIGN:
    1090           0 :                 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             : 
    1107             : static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
    1108             : 
    1109             : static struct inode *iomem_inode;
    1110             : 
    1111             : #ifdef CONFIG_IO_STRICT_DEVMEM
    1112             : static 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
    1144             : static void revoke_iomem(struct resource *res) {}
    1145             : #endif
    1146             : 
    1147           0 : struct 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           0 :         return smp_load_acquire(&iomem_inode)->i_mapping;
    1156             : }
    1157             : 
    1158           0 : static 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           0 :         DECLARE_WAITQUEUE(wait, current);
    1163             : 
    1164           0 :         res->name = name;
    1165           0 :         res->start = start;
    1166           0 :         res->end = start + n - 1;
    1167             : 
    1168             :         for (;;) {
    1169             :                 struct resource *conflict;
    1170             : 
    1171           0 :                 res->flags = resource_type(parent) | resource_ext_type(parent);
    1172           0 :                 res->flags |= IORESOURCE_BUSY | flags;
    1173           0 :                 res->desc = parent->desc;
    1174             : 
    1175           0 :                 conflict = __request_resource(parent, res);
    1176           0 :                 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           0 :                 if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
    1184           0 :                         pr_warn("Unaddressable device %s %pR conflicts with %pR",
    1185             :                                 conflict->name, conflict, res);
    1186             :                 }
    1187           0 :                 if (conflict != parent) {
    1188           0 :                         if (!(conflict->flags & IORESOURCE_BUSY)) {
    1189           0 :                                 parent = conflict;
    1190           0 :                                 continue;
    1191             :                         }
    1192             :                 }
    1193           0 :                 if (conflict->flags & flags & IORESOURCE_MUXED) {
    1194           0 :                         add_wait_queue(&muxed_resource_wait, &wait);
    1195           0 :                         write_unlock(&resource_lock);
    1196           0 :                         set_current_state(TASK_UNINTERRUPTIBLE);
    1197           0 :                         schedule();
    1198           0 :                         remove_wait_queue(&muxed_resource_wait, &wait);
    1199           0 :                         write_lock(&resource_lock);
    1200           0 :                         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             :  */
    1217           0 : struct resource *__request_region(struct resource *parent,
    1218             :                                   resource_size_t start, resource_size_t n,
    1219             :                                   const char *name, int flags)
    1220             : {
    1221           0 :         struct resource *res = alloc_resource(GFP_KERNEL);
    1222             :         int ret;
    1223             : 
    1224           0 :         if (!res)
    1225             :                 return NULL;
    1226             : 
    1227           0 :         write_lock(&resource_lock);
    1228           0 :         ret = __request_region_locked(res, parent, start, n, name, flags);
    1229           0 :         write_unlock(&resource_lock);
    1230             : 
    1231           0 :         if (ret) {
    1232           0 :                 free_resource(res);
    1233           0 :                 return NULL;
    1234             :         }
    1235             : 
    1236             :         if (parent == &iomem_resource)
    1237             :                 revoke_iomem(res);
    1238             : 
    1239             :         return res;
    1240             : }
    1241             : EXPORT_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             :  */
    1251           0 : void __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           0 :         p = &parent->child;
    1258           0 :         end = start + n - 1;
    1259             : 
    1260           0 :         write_lock(&resource_lock);
    1261             : 
    1262             :         for (;;) {
    1263           0 :                 struct resource *res = *p;
    1264             : 
    1265           0 :                 if (!res)
    1266             :                         break;
    1267           0 :                 if (res->start <= start && res->end >= end) {
    1268           0 :                         if (!(res->flags & IORESOURCE_BUSY)) {
    1269           0 :                                 p = &res->child;
    1270           0 :                                 continue;
    1271             :                         }
    1272           0 :                         if (res->start != start || res->end != end)
    1273             :                                 break;
    1274           0 :                         *p = res->sibling;
    1275           0 :                         write_unlock(&resource_lock);
    1276           0 :                         if (res->flags & IORESOURCE_MUXED)
    1277           0 :                                 wake_up(&muxed_resource_wait);
    1278           0 :                         free_resource(res);
    1279           0 :                         return;
    1280             :                 }
    1281           0 :                 p = &res->sibling;
    1282             :         }
    1283             : 
    1284           0 :         write_unlock(&resource_lock);
    1285             : 
    1286           0 :         pr_warn("Trying to free nonexistent resource <%pa-%pa>\n", &start, &end);
    1287             : }
    1288             : EXPORT_SYMBOL(__release_region);
    1289             : 
    1290             : #ifdef CONFIG_MEMORY_HOTREMOVE
    1291             : /**
    1292             :  * release_mem_region_adjustable - release a previously reserved memory region
    1293             :  * @start: resource start address
    1294             :  * @size: resource region size
    1295             :  *
    1296             :  * This interface is intended for memory hot-delete.  The requested region
    1297             :  * is released from a currently busy memory resource.  The requested region
    1298             :  * must either match exactly or fit into a single busy resource entry.  In
    1299             :  * the latter case, the remaining resource is adjusted accordingly.
    1300             :  * Existing children of the busy memory resource must be immutable in the
    1301             :  * request.
    1302             :  *
    1303             :  * Note:
    1304             :  * - Additional release conditions, such as overlapping region, can be
    1305             :  *   supported after they are confirmed as valid cases.
    1306             :  * - When a busy memory resource gets split into two entries, the code
    1307             :  *   assumes that all children remain in the lower address entry for
    1308             :  *   simplicity.  Enhance this logic when necessary.
    1309             :  */
    1310             : void release_mem_region_adjustable(resource_size_t start, resource_size_t size)
    1311             : {
    1312             :         struct resource *parent = &iomem_resource;
    1313             :         struct resource *new_res = NULL;
    1314             :         bool alloc_nofail = false;
    1315             :         struct resource **p;
    1316             :         struct resource *res;
    1317             :         resource_size_t end;
    1318             : 
    1319             :         end = start + size - 1;
    1320             :         if (WARN_ON_ONCE((start < parent->start) || (end > parent->end)))
    1321             :                 return;
    1322             : 
    1323             :         /*
    1324             :          * We free up quite a lot of memory on memory hotunplug (esp., memap),
    1325             :          * just before releasing the region. This is highly unlikely to
    1326             :          * fail - let's play save and make it never fail as the caller cannot
    1327             :          * perform any error handling (e.g., trying to re-add memory will fail
    1328             :          * similarly).
    1329             :          */
    1330             : retry:
    1331             :         new_res = alloc_resource(GFP_KERNEL | (alloc_nofail ? __GFP_NOFAIL : 0));
    1332             : 
    1333             :         p = &parent->child;
    1334             :         write_lock(&resource_lock);
    1335             : 
    1336             :         while ((res = *p)) {
    1337             :                 if (res->start >= end)
    1338             :                         break;
    1339             : 
    1340             :                 /* look for the next resource if it does not fit into */
    1341             :                 if (res->start > start || res->end < end) {
    1342             :                         p = &res->sibling;
    1343             :                         continue;
    1344             :                 }
    1345             : 
    1346             :                 if (!(res->flags & IORESOURCE_MEM))
    1347             :                         break;
    1348             : 
    1349             :                 if (!(res->flags & IORESOURCE_BUSY)) {
    1350             :                         p = &res->child;
    1351             :                         continue;
    1352             :                 }
    1353             : 
    1354             :                 /* found the target resource; let's adjust accordingly */
    1355             :                 if (res->start == start && res->end == end) {
    1356             :                         /* free the whole entry */
    1357             :                         *p = res->sibling;
    1358             :                         free_resource(res);
    1359             :                 } else if (res->start == start && res->end != end) {
    1360             :                         /* adjust the start */
    1361             :                         WARN_ON_ONCE(__adjust_resource(res, end + 1,
    1362             :                                                        res->end - end));
    1363             :                 } else if (res->start != start && res->end == end) {
    1364             :                         /* adjust the end */
    1365             :                         WARN_ON_ONCE(__adjust_resource(res, res->start,
    1366             :                                                        start - res->start));
    1367             :                 } else {
    1368             :                         /* split into two entries - we need a new resource */
    1369             :                         if (!new_res) {
    1370             :                                 new_res = alloc_resource(GFP_ATOMIC);
    1371             :                                 if (!new_res) {
    1372             :                                         alloc_nofail = true;
    1373             :                                         write_unlock(&resource_lock);
    1374             :                                         goto retry;
    1375             :                                 }
    1376             :                         }
    1377             :                         new_res->name = res->name;
    1378             :                         new_res->start = end + 1;
    1379             :                         new_res->end = res->end;
    1380             :                         new_res->flags = res->flags;
    1381             :                         new_res->desc = res->desc;
    1382             :                         new_res->parent = res->parent;
    1383             :                         new_res->sibling = res->sibling;
    1384             :                         new_res->child = NULL;
    1385             : 
    1386             :                         if (WARN_ON_ONCE(__adjust_resource(res, res->start,
    1387             :                                                            start - res->start)))
    1388             :                                 break;
    1389             :                         res->sibling = new_res;
    1390             :                         new_res = NULL;
    1391             :                 }
    1392             : 
    1393             :                 break;
    1394             :         }
    1395             : 
    1396             :         write_unlock(&resource_lock);
    1397             :         free_resource(new_res);
    1398             : }
    1399             : #endif  /* CONFIG_MEMORY_HOTREMOVE */
    1400             : 
    1401             : #ifdef CONFIG_MEMORY_HOTPLUG
    1402             : static bool system_ram_resources_mergeable(struct resource *r1,
    1403             :                                            struct resource *r2)
    1404             : {
    1405             :         /* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
    1406             :         return r1->flags == r2->flags && r1->end + 1 == r2->start &&
    1407             :                r1->name == r2->name && r1->desc == r2->desc &&
    1408             :                !r1->child && !r2->child;
    1409             : }
    1410             : 
    1411             : /**
    1412             :  * merge_system_ram_resource - mark the System RAM resource mergeable and try to
    1413             :  *      merge it with adjacent, mergeable resources
    1414             :  * @res: resource descriptor
    1415             :  *
    1416             :  * This interface is intended for memory hotplug, whereby lots of contiguous
    1417             :  * system ram resources are added (e.g., via add_memory*()) by a driver, and
    1418             :  * the actual resource boundaries are not of interest (e.g., it might be
    1419             :  * relevant for DIMMs). Only resources that are marked mergeable, that have the
    1420             :  * same parent, and that don't have any children are considered. All mergeable
    1421             :  * resources must be immutable during the request.
    1422             :  *
    1423             :  * Note:
    1424             :  * - The caller has to make sure that no pointers to resources that are
    1425             :  *   marked mergeable are used anymore after this call - the resource might
    1426             :  *   be freed and the pointer might be stale!
    1427             :  * - release_mem_region_adjustable() will split on demand on memory hotunplug
    1428             :  */
    1429             : void merge_system_ram_resource(struct resource *res)
    1430             : {
    1431             :         const unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
    1432             :         struct resource *cur;
    1433             : 
    1434             :         if (WARN_ON_ONCE((res->flags & flags) != flags))
    1435             :                 return;
    1436             : 
    1437             :         write_lock(&resource_lock);
    1438             :         res->flags |= IORESOURCE_SYSRAM_MERGEABLE;
    1439             : 
    1440             :         /* Try to merge with next item in the list. */
    1441             :         cur = res->sibling;
    1442             :         if (cur && system_ram_resources_mergeable(res, cur)) {
    1443             :                 res->end = cur->end;
    1444             :                 res->sibling = cur->sibling;
    1445             :                 free_resource(cur);
    1446             :         }
    1447             : 
    1448             :         /* Try to merge with previous item in the list. */
    1449             :         cur = res->parent->child;
    1450             :         while (cur && cur->sibling != res)
    1451             :                 cur = cur->sibling;
    1452             :         if (cur && system_ram_resources_mergeable(cur, res)) {
    1453             :                 cur->end = res->end;
    1454             :                 cur->sibling = res->sibling;
    1455             :                 free_resource(res);
    1456             :         }
    1457             :         write_unlock(&resource_lock);
    1458             : }
    1459             : #endif  /* CONFIG_MEMORY_HOTPLUG */
    1460             : 
    1461             : /*
    1462             :  * Managed region resource
    1463             :  */
    1464           0 : static void devm_resource_release(struct device *dev, void *ptr)
    1465             : {
    1466           0 :         struct resource **r = ptr;
    1467             : 
    1468           0 :         release_resource(*r);
    1469           0 : }
    1470             : 
    1471             : /**
    1472             :  * devm_request_resource() - request and reserve an I/O or memory resource
    1473             :  * @dev: device for which to request the resource
    1474             :  * @root: root of the resource tree from which to request the resource
    1475             :  * @new: descriptor of the resource to request
    1476             :  *
    1477             :  * This is a device-managed version of request_resource(). There is usually
    1478             :  * no need to release resources requested by this function explicitly since
    1479             :  * that will be taken care of when the device is unbound from its driver.
    1480             :  * If for some reason the resource needs to be released explicitly, because
    1481             :  * of ordering issues for example, drivers must call devm_release_resource()
    1482             :  * rather than the regular release_resource().
    1483             :  *
    1484             :  * When a conflict is detected between any existing resources and the newly
    1485             :  * requested resource, an error message will be printed.
    1486             :  *
    1487             :  * Returns 0 on success or a negative error code on failure.
    1488             :  */
    1489           0 : int devm_request_resource(struct device *dev, struct resource *root,
    1490             :                           struct resource *new)
    1491             : {
    1492             :         struct resource *conflict, **ptr;
    1493             : 
    1494           0 :         ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
    1495           0 :         if (!ptr)
    1496             :                 return -ENOMEM;
    1497             : 
    1498           0 :         *ptr = new;
    1499             : 
    1500           0 :         conflict = request_resource_conflict(root, new);
    1501           0 :         if (conflict) {
    1502           0 :                 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
    1503             :                         new, conflict->name, conflict);
    1504           0 :                 devres_free(ptr);
    1505           0 :                 return -EBUSY;
    1506             :         }
    1507             : 
    1508           0 :         devres_add(dev, ptr);
    1509           0 :         return 0;
    1510             : }
    1511             : EXPORT_SYMBOL(devm_request_resource);
    1512             : 
    1513           0 : static int devm_resource_match(struct device *dev, void *res, void *data)
    1514             : {
    1515           0 :         struct resource **ptr = res;
    1516             : 
    1517           0 :         return *ptr == data;
    1518             : }
    1519             : 
    1520             : /**
    1521             :  * devm_release_resource() - release a previously requested resource
    1522             :  * @dev: device for which to release the resource
    1523             :  * @new: descriptor of the resource to release
    1524             :  *
    1525             :  * Releases a resource previously requested using devm_request_resource().
    1526             :  */
    1527           0 : void devm_release_resource(struct device *dev, struct resource *new)
    1528             : {
    1529           0 :         WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
    1530             :                                new));
    1531           0 : }
    1532             : EXPORT_SYMBOL(devm_release_resource);
    1533             : 
    1534             : struct region_devres {
    1535             :         struct resource *parent;
    1536             :         resource_size_t start;
    1537             :         resource_size_t n;
    1538             : };
    1539             : 
    1540           0 : static void devm_region_release(struct device *dev, void *res)
    1541             : {
    1542           0 :         struct region_devres *this = res;
    1543             : 
    1544           0 :         __release_region(this->parent, this->start, this->n);
    1545           0 : }
    1546             : 
    1547           0 : static int devm_region_match(struct device *dev, void *res, void *match_data)
    1548             : {
    1549           0 :         struct region_devres *this = res, *match = match_data;
    1550             : 
    1551           0 :         return this->parent == match->parent &&
    1552           0 :                 this->start == match->start && this->n == match->n;
    1553             : }
    1554             : 
    1555             : struct resource *
    1556           0 : __devm_request_region(struct device *dev, struct resource *parent,
    1557             :                       resource_size_t start, resource_size_t n, const char *name)
    1558             : {
    1559           0 :         struct region_devres *dr = NULL;
    1560             :         struct resource *res;
    1561             : 
    1562           0 :         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
    1563             :                           GFP_KERNEL);
    1564           0 :         if (!dr)
    1565             :                 return NULL;
    1566             : 
    1567           0 :         dr->parent = parent;
    1568           0 :         dr->start = start;
    1569           0 :         dr->n = n;
    1570             : 
    1571           0 :         res = __request_region(parent, start, n, name, 0);
    1572           0 :         if (res)
    1573           0 :                 devres_add(dev, dr);
    1574             :         else
    1575           0 :                 devres_free(dr);
    1576             : 
    1577             :         return res;
    1578             : }
    1579             : EXPORT_SYMBOL(__devm_request_region);
    1580             : 
    1581           0 : void __devm_release_region(struct device *dev, struct resource *parent,
    1582             :                            resource_size_t start, resource_size_t n)
    1583             : {
    1584           0 :         struct region_devres match_data = { parent, start, n };
    1585             : 
    1586           0 :         __release_region(parent, start, n);
    1587           0 :         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
    1588             :                                &match_data));
    1589           0 : }
    1590             : EXPORT_SYMBOL(__devm_release_region);
    1591             : 
    1592             : /*
    1593             :  * Reserve I/O ports or memory based on "reserve=" kernel parameter.
    1594             :  */
    1595             : #define MAXRESERVE 4
    1596           0 : static int __init reserve_setup(char *str)
    1597             : {
    1598             :         static int reserved;
    1599             :         static struct resource reserve[MAXRESERVE];
    1600             : 
    1601           0 :         for (;;) {
    1602             :                 unsigned int io_start, io_num;
    1603           0 :                 int x = reserved;
    1604             :                 struct resource *parent;
    1605             : 
    1606           0 :                 if (get_option(&str, &io_start) != 2)
    1607             :                         break;
    1608           0 :                 if (get_option(&str, &io_num) == 0)
    1609             :                         break;
    1610           0 :                 if (x < MAXRESERVE) {
    1611           0 :                         struct resource *res = reserve + x;
    1612             : 
    1613             :                         /*
    1614             :                          * If the region starts below 0x10000, we assume it's
    1615             :                          * I/O port space; otherwise assume it's memory.
    1616             :                          */
    1617           0 :                         if (io_start < 0x10000) {
    1618           0 :                                 res->flags = IORESOURCE_IO;
    1619           0 :                                 parent = &ioport_resource;
    1620             :                         } else {
    1621           0 :                                 res->flags = IORESOURCE_MEM;
    1622           0 :                                 parent = &iomem_resource;
    1623             :                         }
    1624           0 :                         res->name = "reserved";
    1625           0 :                         res->start = io_start;
    1626           0 :                         res->end = io_start + io_num - 1;
    1627           0 :                         res->flags |= IORESOURCE_BUSY;
    1628           0 :                         res->desc = IORES_DESC_NONE;
    1629           0 :                         res->child = NULL;
    1630           0 :                         if (request_resource(parent, res) == 0)
    1631           0 :                                 reserved = x+1;
    1632             :                 }
    1633             :         }
    1634           0 :         return 1;
    1635             : }
    1636             : __setup("reserve=", reserve_setup);
    1637             : 
    1638             : /*
    1639             :  * Check if the requested addr and size spans more than any slot in the
    1640             :  * iomem resource tree.
    1641             :  */
    1642           0 : int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
    1643             : {
    1644           0 :         struct resource *p = &iomem_resource;
    1645           0 :         resource_size_t end = addr + size - 1;
    1646           0 :         int err = 0;
    1647             :         loff_t l;
    1648             : 
    1649           0 :         read_lock(&resource_lock);
    1650           0 :         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
    1651             :                 /*
    1652             :                  * We can probably skip the resources without
    1653             :                  * IORESOURCE_IO attribute?
    1654             :                  */
    1655           0 :                 if (p->start > end)
    1656           0 :                         continue;
    1657           0 :                 if (p->end < addr)
    1658           0 :                         continue;
    1659           0 :                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
    1660           0 :                     PFN_DOWN(p->end) >= PFN_DOWN(end))
    1661           0 :                         continue;
    1662             :                 /*
    1663             :                  * if a resource is "BUSY", it's not a hardware resource
    1664             :                  * but a driver mapping of such a resource; we don't want
    1665             :                  * to warn for those; some drivers legitimately map only
    1666             :                  * partial hardware resources. (example: vesafb)
    1667             :                  */
    1668           0 :                 if (p->flags & IORESOURCE_BUSY)
    1669           0 :                         continue;
    1670             : 
    1671           0 :                 pr_warn("resource sanity check: requesting [mem %pa-%pa], which spans more than %s %pR\n",
    1672             :                         &addr, &end, p->name, p);
    1673           0 :                 err = -1;
    1674           0 :                 break;
    1675             :         }
    1676           0 :         read_unlock(&resource_lock);
    1677             : 
    1678           0 :         return err;
    1679             : }
    1680             : 
    1681             : #ifdef CONFIG_STRICT_DEVMEM
    1682             : static int strict_iomem_checks = 1;
    1683             : #else
    1684             : static int strict_iomem_checks;
    1685             : #endif
    1686             : 
    1687             : /*
    1688             :  * Check if an address is exclusive to the kernel and must not be mapped to
    1689             :  * user space, for example, via /dev/mem.
    1690             :  *
    1691             :  * Returns true if exclusive to the kernel, otherwise returns false.
    1692             :  */
    1693           0 : bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size)
    1694             : {
    1695           0 :         const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
    1696             :                                                   IORESOURCE_EXCLUSIVE;
    1697           0 :         bool skip_children = false, err = false;
    1698             :         struct resource *p;
    1699             : 
    1700           0 :         read_lock(&resource_lock);
    1701           0 :         for_each_resource(root, p, skip_children) {
    1702           0 :                 if (p->start >= addr + size)
    1703             :                         break;
    1704           0 :                 if (p->end < addr) {
    1705           0 :                         skip_children = true;
    1706           0 :                         continue;
    1707             :                 }
    1708           0 :                 skip_children = false;
    1709             : 
    1710             :                 /*
    1711             :                  * IORESOURCE_SYSTEM_RAM resources are exclusive if
    1712             :                  * IORESOURCE_EXCLUSIVE is set, even if they
    1713             :                  * are not busy and even if "iomem=relaxed" is set. The
    1714             :                  * responsible driver dynamically adds/removes system RAM within
    1715             :                  * such an area and uncontrolled access is dangerous.
    1716             :                  */
    1717           0 :                 if ((p->flags & exclusive_system_ram) == exclusive_system_ram) {
    1718             :                         err = true;
    1719             :                         break;
    1720             :                 }
    1721             : 
    1722             :                 /*
    1723             :                  * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
    1724             :                  * or CONFIG_IO_STRICT_DEVMEM is enabled and the
    1725             :                  * resource is busy.
    1726             :                  */
    1727           0 :                 if (!strict_iomem_checks || !(p->flags & IORESOURCE_BUSY))
    1728           0 :                         continue;
    1729           0 :                 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
    1730           0 :                                 || p->flags & IORESOURCE_EXCLUSIVE) {
    1731             :                         err = true;
    1732             :                         break;
    1733             :                 }
    1734             :         }
    1735           0 :         read_unlock(&resource_lock);
    1736             : 
    1737           0 :         return err;
    1738             : }
    1739             : 
    1740           0 : bool iomem_is_exclusive(u64 addr)
    1741             : {
    1742           0 :         return resource_is_exclusive(&iomem_resource, addr & PAGE_MASK,
    1743             :                                      PAGE_SIZE);
    1744             : }
    1745             : 
    1746           0 : struct resource_entry *resource_list_create_entry(struct resource *res,
    1747             :                                                   size_t extra_size)
    1748             : {
    1749             :         struct resource_entry *entry;
    1750             : 
    1751           0 :         entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
    1752           0 :         if (entry) {
    1753           0 :                 INIT_LIST_HEAD(&entry->node);
    1754           0 :                 entry->res = res ? res : &entry->__res;
    1755             :         }
    1756             : 
    1757           0 :         return entry;
    1758             : }
    1759             : EXPORT_SYMBOL(resource_list_create_entry);
    1760             : 
    1761           0 : void resource_list_free(struct list_head *head)
    1762             : {
    1763             :         struct resource_entry *entry, *tmp;
    1764             : 
    1765           0 :         list_for_each_entry_safe(entry, tmp, head, node)
    1766           0 :                 resource_list_destroy_entry(entry);
    1767           0 : }
    1768             : EXPORT_SYMBOL(resource_list_free);
    1769             : 
    1770             : #ifdef CONFIG_GET_FREE_REGION
    1771             : #define GFR_DESCENDING          (1UL << 0)
    1772             : #define GFR_REQUEST_REGION      (1UL << 1)
    1773             : #define GFR_DEFAULT_ALIGN (1UL << PA_SECTION_SHIFT)
    1774             : 
    1775             : static resource_size_t gfr_start(struct resource *base, resource_size_t size,
    1776             :                                  resource_size_t align, unsigned long flags)
    1777             : {
    1778             :         if (flags & GFR_DESCENDING) {
    1779             :                 resource_size_t end;
    1780             : 
    1781             :                 end = min_t(resource_size_t, base->end,
    1782             :                             (1ULL << MAX_PHYSMEM_BITS) - 1);
    1783             :                 return end - size + 1;
    1784             :         }
    1785             : 
    1786             :         return ALIGN(base->start, align);
    1787             : }
    1788             : 
    1789             : static bool gfr_continue(struct resource *base, resource_size_t addr,
    1790             :                          resource_size_t size, unsigned long flags)
    1791             : {
    1792             :         if (flags & GFR_DESCENDING)
    1793             :                 return addr > size && addr >= base->start;
    1794             :         /*
    1795             :          * In the ascend case be careful that the last increment by
    1796             :          * @size did not wrap 0.
    1797             :          */
    1798             :         return addr > addr - size &&
    1799             :                addr <= min_t(resource_size_t, base->end,
    1800             :                              (1ULL << MAX_PHYSMEM_BITS) - 1);
    1801             : }
    1802             : 
    1803             : static resource_size_t gfr_next(resource_size_t addr, resource_size_t size,
    1804             :                                 unsigned long flags)
    1805             : {
    1806             :         if (flags & GFR_DESCENDING)
    1807             :                 return addr - size;
    1808             :         return addr + size;
    1809             : }
    1810             : 
    1811             : static void remove_free_mem_region(void *_res)
    1812             : {
    1813             :         struct resource *res = _res;
    1814             : 
    1815             :         if (res->parent)
    1816             :                 remove_resource(res);
    1817             :         free_resource(res);
    1818             : }
    1819             : 
    1820             : static struct resource *
    1821             : get_free_mem_region(struct device *dev, struct resource *base,
    1822             :                     resource_size_t size, const unsigned long align,
    1823             :                     const char *name, const unsigned long desc,
    1824             :                     const unsigned long flags)
    1825             : {
    1826             :         resource_size_t addr;
    1827             :         struct resource *res;
    1828             :         struct region_devres *dr = NULL;
    1829             : 
    1830             :         size = ALIGN(size, align);
    1831             : 
    1832             :         res = alloc_resource(GFP_KERNEL);
    1833             :         if (!res)
    1834             :                 return ERR_PTR(-ENOMEM);
    1835             : 
    1836             :         if (dev && (flags & GFR_REQUEST_REGION)) {
    1837             :                 dr = devres_alloc(devm_region_release,
    1838             :                                 sizeof(struct region_devres), GFP_KERNEL);
    1839             :                 if (!dr) {
    1840             :                         free_resource(res);
    1841             :                         return ERR_PTR(-ENOMEM);
    1842             :                 }
    1843             :         } else if (dev) {
    1844             :                 if (devm_add_action_or_reset(dev, remove_free_mem_region, res))
    1845             :                         return ERR_PTR(-ENOMEM);
    1846             :         }
    1847             : 
    1848             :         write_lock(&resource_lock);
    1849             :         for (addr = gfr_start(base, size, align, flags);
    1850             :              gfr_continue(base, addr, size, flags);
    1851             :              addr = gfr_next(addr, size, flags)) {
    1852             :                 if (__region_intersects(base, addr, size, 0, IORES_DESC_NONE) !=
    1853             :                     REGION_DISJOINT)
    1854             :                         continue;
    1855             : 
    1856             :                 if (flags & GFR_REQUEST_REGION) {
    1857             :                         if (__request_region_locked(res, &iomem_resource, addr,
    1858             :                                                     size, name, 0))
    1859             :                                 break;
    1860             : 
    1861             :                         if (dev) {
    1862             :                                 dr->parent = &iomem_resource;
    1863             :                                 dr->start = addr;
    1864             :                                 dr->n = size;
    1865             :                                 devres_add(dev, dr);
    1866             :                         }
    1867             : 
    1868             :                         res->desc = desc;
    1869             :                         write_unlock(&resource_lock);
    1870             : 
    1871             : 
    1872             :                         /*
    1873             :                          * A driver is claiming this region so revoke any
    1874             :                          * mappings.
    1875             :                          */
    1876             :                         revoke_iomem(res);
    1877             :                 } else {
    1878             :                         res->start = addr;
    1879             :                         res->end = addr + size - 1;
    1880             :                         res->name = name;
    1881             :                         res->desc = desc;
    1882             :                         res->flags = IORESOURCE_MEM;
    1883             : 
    1884             :                         /*
    1885             :                          * Only succeed if the resource hosts an exclusive
    1886             :                          * range after the insert
    1887             :                          */
    1888             :                         if (__insert_resource(base, res) || res->child)
    1889             :                                 break;
    1890             : 
    1891             :                         write_unlock(&resource_lock);
    1892             :                 }
    1893             : 
    1894             :                 return res;
    1895             :         }
    1896             :         write_unlock(&resource_lock);
    1897             : 
    1898             :         if (flags & GFR_REQUEST_REGION) {
    1899             :                 free_resource(res);
    1900             :                 devres_free(dr);
    1901             :         } else if (dev)
    1902             :                 devm_release_action(dev, remove_free_mem_region, res);
    1903             : 
    1904             :         return ERR_PTR(-ERANGE);
    1905             : }
    1906             : 
    1907             : /**
    1908             :  * devm_request_free_mem_region - find free region for device private memory
    1909             :  *
    1910             :  * @dev: device struct to bind the resource to
    1911             :  * @size: size in bytes of the device memory to add
    1912             :  * @base: resource tree to look in
    1913             :  *
    1914             :  * This function tries to find an empty range of physical address big enough to
    1915             :  * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
    1916             :  * memory, which in turn allocates struct pages.
    1917             :  */
    1918             : struct resource *devm_request_free_mem_region(struct device *dev,
    1919             :                 struct resource *base, unsigned long size)
    1920             : {
    1921             :         unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
    1922             : 
    1923             :         return get_free_mem_region(dev, base, size, GFR_DEFAULT_ALIGN,
    1924             :                                    dev_name(dev),
    1925             :                                    IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
    1926             : }
    1927             : EXPORT_SYMBOL_GPL(devm_request_free_mem_region);
    1928             : 
    1929             : struct resource *request_free_mem_region(struct resource *base,
    1930             :                 unsigned long size, const char *name)
    1931             : {
    1932             :         unsigned long flags = GFR_DESCENDING | GFR_REQUEST_REGION;
    1933             : 
    1934             :         return get_free_mem_region(NULL, base, size, GFR_DEFAULT_ALIGN, name,
    1935             :                                    IORES_DESC_DEVICE_PRIVATE_MEMORY, flags);
    1936             : }
    1937             : EXPORT_SYMBOL_GPL(request_free_mem_region);
    1938             : 
    1939             : /**
    1940             :  * alloc_free_mem_region - find a free region relative to @base
    1941             :  * @base: resource that will parent the new resource
    1942             :  * @size: size in bytes of memory to allocate from @base
    1943             :  * @align: alignment requirements for the allocation
    1944             :  * @name: resource name
    1945             :  *
    1946             :  * Buses like CXL, that can dynamically instantiate new memory regions,
    1947             :  * need a method to allocate physical address space for those regions.
    1948             :  * Allocate and insert a new resource to cover a free, unclaimed by a
    1949             :  * descendant of @base, range in the span of @base.
    1950             :  */
    1951             : struct resource *alloc_free_mem_region(struct resource *base,
    1952             :                                        unsigned long size, unsigned long align,
    1953             :                                        const char *name)
    1954             : {
    1955             :         /* Default of ascending direction and insert resource */
    1956             :         unsigned long flags = 0;
    1957             : 
    1958             :         return get_free_mem_region(NULL, base, size, align, name,
    1959             :                                    IORES_DESC_NONE, flags);
    1960             : }
    1961             : EXPORT_SYMBOL_NS_GPL(alloc_free_mem_region, CXL);
    1962             : #endif /* CONFIG_GET_FREE_REGION */
    1963             : 
    1964           0 : static int __init strict_iomem(char *str)
    1965             : {
    1966           0 :         if (strstr(str, "relaxed"))
    1967           0 :                 strict_iomem_checks = 0;
    1968           0 :         if (strstr(str, "strict"))
    1969           0 :                 strict_iomem_checks = 1;
    1970           0 :         return 1;
    1971             : }
    1972             : 
    1973           1 : static int iomem_fs_init_fs_context(struct fs_context *fc)
    1974             : {
    1975           1 :         return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
    1976             : }
    1977             : 
    1978             : static struct file_system_type iomem_fs_type = {
    1979             :         .name           = "iomem",
    1980             :         .owner          = THIS_MODULE,
    1981             :         .init_fs_context = iomem_fs_init_fs_context,
    1982             :         .kill_sb        = kill_anon_super,
    1983             : };
    1984             : 
    1985           1 : static int __init iomem_init_inode(void)
    1986             : {
    1987             :         static struct vfsmount *iomem_vfs_mount;
    1988             :         static int iomem_fs_cnt;
    1989             :         struct inode *inode;
    1990             :         int rc;
    1991             : 
    1992           1 :         rc = simple_pin_fs(&iomem_fs_type, &iomem_vfs_mount, &iomem_fs_cnt);
    1993           1 :         if (rc < 0) {
    1994           0 :                 pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc);
    1995           0 :                 return rc;
    1996             :         }
    1997             : 
    1998           1 :         inode = alloc_anon_inode(iomem_vfs_mount->mnt_sb);
    1999           1 :         if (IS_ERR(inode)) {
    2000           0 :                 rc = PTR_ERR(inode);
    2001           0 :                 pr_err("Cannot allocate inode for iomem: %d\n", rc);
    2002           0 :                 simple_release_fs(&iomem_vfs_mount, &iomem_fs_cnt);
    2003           0 :                 return rc;
    2004             :         }
    2005             : 
    2006             :         /*
    2007             :          * Publish iomem revocation inode initialized.
    2008             :          * Pairs with smp_load_acquire() in revoke_iomem().
    2009             :          */
    2010           1 :         smp_store_release(&iomem_inode, inode);
    2011             : 
    2012           1 :         return 0;
    2013             : }
    2014             : 
    2015             : fs_initcall(iomem_init_inode);
    2016             : 
    2017             : __setup("iomem=", strict_iomem);

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