// SPDX-License-Identifier: GPL-2.0-only /* * linux/kernel/resource.c * * Copyright (C) 1999 Linus Torvalds * Copyright (C) 1999 Martin Mares <[email protected]> * * Arbitrary resource management. */ #define pr_fmt(fmt) … #include <linux/export.h> #include <linux/errno.h> #include <linux/ioport.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/fs.h> #include <linux/proc_fs.h> #include <linux/pseudo_fs.h> #include <linux/sched.h> #include <linux/seq_file.h> #include <linux/device.h> #include <linux/pfn.h> #include <linux/mm.h> #include <linux/mount.h> #include <linux/resource_ext.h> #include <uapi/linux/magic.h> #include <linux/string.h> #include <linux/vmalloc.h> #include <asm/io.h> struct resource ioport_resource = …; EXPORT_SYMBOL(…); struct resource iomem_resource = …; EXPORT_SYMBOL(…); static DEFINE_RWLOCK(resource_lock); static struct resource *next_resource(struct resource *p, bool skip_children) { … } #define for_each_resource(_root, _p, _skip_children) … #ifdef CONFIG_PROC_FS enum { … }; static void *r_start(struct seq_file *m, loff_t *pos) __acquires(resource_lock) { … } static void *r_next(struct seq_file *m, void *v, loff_t *pos) { … } static void r_stop(struct seq_file *m, void *v) __releases(resource_lock) { … } static int r_show(struct seq_file *m, void *v) { … } static const struct seq_operations resource_op = …; static int __init ioresources_init(void) { … } __initcall(ioresources_init); #endif /* CONFIG_PROC_FS */ static void free_resource(struct resource *res) { … } static struct resource *alloc_resource(gfp_t flags) { … } /* Return the conflict entry if you can't request it */ static struct resource * __request_resource(struct resource *root, struct resource *new) { … } static int __release_resource(struct resource *old, bool release_child) { … } static void __release_child_resources(struct resource *r) { … } void release_child_resources(struct resource *r) { … } /** * request_resource_conflict - request and reserve an I/O or memory resource * @root: root resource descriptor * @new: resource descriptor desired by caller * * Returns 0 for success, conflict resource on error. */ struct resource *request_resource_conflict(struct resource *root, struct resource *new) { … } /** * request_resource - request and reserve an I/O or memory resource * @root: root resource descriptor * @new: resource descriptor desired by caller * * Returns 0 for success, negative error code on error. */ int request_resource(struct resource *root, struct resource *new) { … } EXPORT_SYMBOL(…); /** * release_resource - release a previously reserved resource * @old: resource pointer */ int release_resource(struct resource *old) { … } EXPORT_SYMBOL(…); /** * find_next_iomem_res - Finds the lowest iomem resource that covers part of * [@start..@end]. * * If a resource is found, returns 0 and @*res is overwritten with the part * of the resource that's within [@start..@end]; if none is found, returns * -ENODEV. Returns -EINVAL for invalid parameters. * * @start: start address of the resource searched for * @end: end address of same resource * @flags: flags which the resource must have * @desc: descriptor the resource must have * @res: return ptr, if resource found * * The caller must specify @start, @end, @flags, and @desc * (which may be IORES_DESC_NONE). */ static int find_next_iomem_res(resource_size_t start, resource_size_t end, unsigned long flags, unsigned long desc, struct resource *res) { … } static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, unsigned long flags, unsigned long desc, void *arg, int (*func)(struct resource *, void *)) { … } /** * walk_iomem_res_desc - Walks through iomem resources and calls func() * with matching resource ranges. * * * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check. * @flags: I/O resource flags * @start: start addr * @end: end addr * @arg: function argument for the callback @func * @func: callback function that is called for each qualifying resource area * * All the memory ranges which overlap start,end and also match flags and * desc are valid candidates. * * NOTE: For a new descriptor search, define a new IORES_DESC in * <linux/ioport.h> and set it in 'desc' of a target resource entry. */ int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { … } EXPORT_SYMBOL_GPL(…); /* * This function calls the @func callback against all memory ranges of type * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY. * Now, this function is only for System RAM, it deals with full ranges and * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate * ranges. */ int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { … } /* * This function, being a variant of walk_system_ram_res(), calls the @func * callback against all memory ranges of type System RAM which are marked as * IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY in reversed order, i.e., from * higher to lower. */ int walk_system_ram_res_rev(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { … } /* * This function calls the @func callback against all memory ranges, which * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY. */ int walk_mem_res(u64 start, u64 end, void *arg, int (*func)(struct resource *, void *)) { … } /* * This function calls the @func callback against all memory ranges of type * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY. * It is to be used only for System RAM. */ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)) { … } static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg) { … } /* * This generic page_is_ram() returns true if specified address is * registered as System RAM in iomem_resource list. */ int __weak page_is_ram(unsigned long pfn) { … } EXPORT_SYMBOL_GPL(…); static int __region_intersects(struct resource *parent, resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { … } /** * region_intersects() - determine intersection of region with known resources * @start: region start address * @size: size of region * @flags: flags of resource (in iomem_resource) * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE * * Check if the specified region partially overlaps or fully eclipses a * resource identified by @flags and @desc (optional with IORES_DESC_NONE). * Return REGION_DISJOINT if the region does not overlap @flags/@desc, * return REGION_MIXED if the region overlaps @flags/@desc and another * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc * and no other defined resource. Note that REGION_INTERSECTS is also * returned in the case when the specified region overlaps RAM and undefined * memory holes. * * region_intersect() is used by memory remapping functions to ensure * the user is not remapping RAM and is a vast speed up over walking * through the resource table page by page. */ int region_intersects(resource_size_t start, size_t size, unsigned long flags, unsigned long desc) { … } EXPORT_SYMBOL_GPL(…); void __weak arch_remove_reservations(struct resource *avail) { … } static void resource_clip(struct resource *res, resource_size_t min, resource_size_t max) { … } /* * Find empty space in the resource tree with the given range and * alignment constraints */ static int __find_resource_space(struct resource *root, struct resource *old, struct resource *new, resource_size_t size, struct resource_constraint *constraint) { … } /** * find_resource_space - Find empty space in the resource tree * @root: Root resource descriptor * @new: Resource descriptor awaiting an empty resource space * @size: The minimum size of the empty space * @constraint: The range and alignment constraints to be met * * Finds an empty space under @root in the resource tree satisfying range and * alignment @constraints. * * Return: * * %0 - if successful, @new members start, end, and flags are altered. * * %-EBUSY - if no empty space was found. */ int find_resource_space(struct resource *root, struct resource *new, resource_size_t size, struct resource_constraint *constraint) { … } EXPORT_SYMBOL_GPL(…); /** * reallocate_resource - allocate a slot in the resource tree given range & alignment. * The resource will be relocated if the new size cannot be reallocated in the * current location. * * @root: root resource descriptor * @old: resource descriptor desired by caller * @newsize: new size of the resource descriptor * @constraint: the size and alignment constraints to be met. */ static int reallocate_resource(struct resource *root, struct resource *old, resource_size_t newsize, struct resource_constraint *constraint) { … } /** * allocate_resource - allocate empty slot in the resource tree given range & alignment. * The resource will be reallocated with a new size if it was already allocated * @root: root resource descriptor * @new: resource descriptor desired by caller * @size: requested resource region size * @min: minimum boundary to allocate * @max: maximum boundary to allocate * @align: alignment requested, in bytes * @alignf: alignment function, optional, called if not NULL * @alignf_data: arbitrary data to pass to the @alignf function */ int allocate_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, resource_alignf alignf, void *alignf_data) { … } EXPORT_SYMBOL(…); /** * lookup_resource - find an existing resource by a resource start address * @root: root resource descriptor * @start: resource start address * * Returns a pointer to the resource if found, NULL otherwise */ struct resource *lookup_resource(struct resource *root, resource_size_t start) { … } /* * Insert a resource into the resource tree. If successful, return NULL, * otherwise return the conflicting resource (compare to __request_resource()) */ static struct resource * __insert_resource(struct resource *parent, struct resource *new) { … } /** * insert_resource_conflict - Inserts resource in the resource tree * @parent: parent of the new resource * @new: new resource to insert * * Returns 0 on success, conflict resource if the resource can't be inserted. * * This function is equivalent to request_resource_conflict when no conflict * happens. If a conflict happens, and the conflicting resources * entirely fit within the range of the new resource, then the new * resource is inserted and the conflicting resources become children of * the new resource. * * This function is intended for producers of resources, such as FW modules * and bus drivers. */ struct resource *insert_resource_conflict(struct resource *parent, struct resource *new) { … } /** * insert_resource - Inserts a resource in the resource tree * @parent: parent of the new resource * @new: new resource to insert * * Returns 0 on success, -EBUSY if the resource can't be inserted. * * This function is intended for producers of resources, such as FW modules * and bus drivers. */ int insert_resource(struct resource *parent, struct resource *new) { … } EXPORT_SYMBOL_GPL(…); /** * insert_resource_expand_to_fit - Insert a resource into the resource tree * @root: root resource descriptor * @new: new resource to insert * * Insert a resource into the resource tree, possibly expanding it in order * to make it encompass any conflicting resources. */ void insert_resource_expand_to_fit(struct resource *root, struct resource *new) { … } /* * Not for general consumption, only early boot memory map parsing, PCI * resource discovery, and late discovery of CXL resources are expected * to use this interface. The former are built-in and only the latter, * CXL, is a module. */ EXPORT_SYMBOL_NS_GPL(…); /** * remove_resource - Remove a resource in the resource tree * @old: resource to remove * * Returns 0 on success, -EINVAL if the resource is not valid. * * This function removes a resource previously inserted by insert_resource() * or insert_resource_conflict(), and moves the children (if any) up to * where they were before. insert_resource() and insert_resource_conflict() * insert a new resource, and move any conflicting resources down to the * children of the new resource. * * insert_resource(), insert_resource_conflict() and remove_resource() are * intended for producers of resources, such as FW modules and bus drivers. */ int remove_resource(struct resource *old) { … } EXPORT_SYMBOL_GPL(…); static int __adjust_resource(struct resource *res, resource_size_t start, resource_size_t size) { … } /** * adjust_resource - modify a resource's start and size * @res: resource to modify * @start: new start value * @size: new size * * Given an existing resource, change its start and size to match the * arguments. Returns 0 on success, -EBUSY if it can't fit. * Existing children of the resource are assumed to be immutable. */ int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size) { … } EXPORT_SYMBOL(…); static void __init __reserve_region_with_split(struct resource *root, resource_size_t start, resource_size_t end, const char *name) { … } void __init reserve_region_with_split(struct resource *root, resource_size_t start, resource_size_t end, const char *name) { … } /** * resource_alignment - calculate resource's alignment * @res: resource pointer * * Returns alignment on success, 0 (invalid alignment) on failure. */ resource_size_t resource_alignment(struct resource *res) { … } /* * This is compatibility stuff for IO resources. * * Note how this, unlike the above, knows about * the IO flag meanings (busy etc). * * request_region creates a new busy region. * * release_region releases a matching busy region. */ static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait); static struct inode *iomem_inode; #ifdef CONFIG_IO_STRICT_DEVMEM static void revoke_iomem(struct resource *res) { … } #else static void revoke_iomem(struct resource *res) {} #endif struct address_space *iomem_get_mapping(void) { … } static int __request_region_locked(struct resource *res, struct resource *parent, resource_size_t start, resource_size_t n, const char *name, int flags) { … } /** * __request_region - create a new busy resource region * @parent: parent resource descriptor * @start: resource start address * @n: resource region size * @name: reserving caller's ID string * @flags: IO resource flags */ struct resource *__request_region(struct resource *parent, resource_size_t start, resource_size_t n, const char *name, int flags) { … } EXPORT_SYMBOL(…); /** * __release_region - release a previously reserved resource region * @parent: parent resource descriptor * @start: resource start address * @n: resource region size * * The described resource region must match a currently busy region. */ void __release_region(struct resource *parent, resource_size_t start, resource_size_t n) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_MEMORY_HOTREMOVE /** * release_mem_region_adjustable - release a previously reserved memory region * @start: resource start address * @size: resource region size * * This interface is intended for memory hot-delete. The requested region * is released from a currently busy memory resource. The requested region * must either match exactly or fit into a single busy resource entry. In * the latter case, the remaining resource is adjusted accordingly. * Existing children of the busy memory resource must be immutable in the * request. * * Note: * - Additional release conditions, such as overlapping region, can be * supported after they are confirmed as valid cases. * - When a busy memory resource gets split into two entries, the code * assumes that all children remain in the lower address entry for * simplicity. Enhance this logic when necessary. */ void release_mem_region_adjustable(resource_size_t start, resource_size_t size) { … } #endif /* CONFIG_MEMORY_HOTREMOVE */ #ifdef CONFIG_MEMORY_HOTPLUG static bool system_ram_resources_mergeable(struct resource *r1, struct resource *r2) { … } /** * merge_system_ram_resource - mark the System RAM resource mergeable and try to * merge it with adjacent, mergeable resources * @res: resource descriptor * * This interface is intended for memory hotplug, whereby lots of contiguous * system ram resources are added (e.g., via add_memory*()) by a driver, and * the actual resource boundaries are not of interest (e.g., it might be * relevant for DIMMs). Only resources that are marked mergeable, that have the * same parent, and that don't have any children are considered. All mergeable * resources must be immutable during the request. * * Note: * - The caller has to make sure that no pointers to resources that are * marked mergeable are used anymore after this call - the resource might * be freed and the pointer might be stale! * - release_mem_region_adjustable() will split on demand on memory hotunplug */ void merge_system_ram_resource(struct resource *res) { … } #endif /* CONFIG_MEMORY_HOTPLUG */ /* * Managed region resource */ static void devm_resource_release(struct device *dev, void *ptr) { … } /** * devm_request_resource() - request and reserve an I/O or memory resource * @dev: device for which to request the resource * @root: root of the resource tree from which to request the resource * @new: descriptor of the resource to request * * This is a device-managed version of request_resource(). There is usually * no need to release resources requested by this function explicitly since * that will be taken care of when the device is unbound from its driver. * If for some reason the resource needs to be released explicitly, because * of ordering issues for example, drivers must call devm_release_resource() * rather than the regular release_resource(). * * When a conflict is detected between any existing resources and the newly * requested resource, an error message will be printed. * * Returns 0 on success or a negative error code on failure. */ int devm_request_resource(struct device *dev, struct resource *root, struct resource *new) { … } EXPORT_SYMBOL(…); static int devm_resource_match(struct device *dev, void *res, void *data) { … } /** * devm_release_resource() - release a previously requested resource * @dev: device for which to release the resource * @new: descriptor of the resource to release * * Releases a resource previously requested using devm_request_resource(). */ void devm_release_resource(struct device *dev, struct resource *new) { … } EXPORT_SYMBOL(…); struct region_devres { … }; static void devm_region_release(struct device *dev, void *res) { … } static int devm_region_match(struct device *dev, void *res, void *match_data) { … } struct resource * __devm_request_region(struct device *dev, struct resource *parent, resource_size_t start, resource_size_t n, const char *name) { … } EXPORT_SYMBOL(…); void __devm_release_region(struct device *dev, struct resource *parent, resource_size_t start, resource_size_t n) { … } EXPORT_SYMBOL(…); /* * Reserve I/O ports or memory based on "reserve=" kernel parameter. */ #define MAXRESERVE … static int __init reserve_setup(char *str) { … } __setup(…); /* * Check if the requested addr and size spans more than any slot in the * iomem resource tree. */ int iomem_map_sanity_check(resource_size_t addr, unsigned long size) { … } #ifdef CONFIG_STRICT_DEVMEM static int strict_iomem_checks = …; #else static int strict_iomem_checks; #endif /* * Check if an address is exclusive to the kernel and must not be mapped to * user space, for example, via /dev/mem. * * Returns true if exclusive to the kernel, otherwise returns false. */ bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size) { … } bool iomem_is_exclusive(u64 addr) { … } struct resource_entry *resource_list_create_entry(struct resource *res, size_t extra_size) { … } EXPORT_SYMBOL(…); void resource_list_free(struct list_head *head) { … } EXPORT_SYMBOL(…); #ifdef CONFIG_GET_FREE_REGION #define GFR_DESCENDING … #define GFR_REQUEST_REGION … #define GFR_DEFAULT_ALIGN … static resource_size_t gfr_start(struct resource *base, resource_size_t size, resource_size_t align, unsigned long flags) { … } static bool gfr_continue(struct resource *base, resource_size_t addr, resource_size_t size, unsigned long flags) { … } static resource_size_t gfr_next(resource_size_t addr, resource_size_t size, unsigned long flags) { … } static void remove_free_mem_region(void *_res) { … } static struct resource * get_free_mem_region(struct device *dev, struct resource *base, resource_size_t size, const unsigned long align, const char *name, const unsigned long desc, const unsigned long flags) { … } /** * devm_request_free_mem_region - find free region for device private memory * * @dev: device struct to bind the resource to * @size: size in bytes of the device memory to add * @base: resource tree to look in * * This function tries to find an empty range of physical address big enough to * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE * memory, which in turn allocates struct pages. */ struct resource *devm_request_free_mem_region(struct device *dev, struct resource *base, unsigned long size) { … } EXPORT_SYMBOL_GPL(…); struct resource *request_free_mem_region(struct resource *base, unsigned long size, const char *name) { … } EXPORT_SYMBOL_GPL(…); /** * alloc_free_mem_region - find a free region relative to @base * @base: resource that will parent the new resource * @size: size in bytes of memory to allocate from @base * @align: alignment requirements for the allocation * @name: resource name * * Buses like CXL, that can dynamically instantiate new memory regions, * need a method to allocate physical address space for those regions. * Allocate and insert a new resource to cover a free, unclaimed by a * descendant of @base, range in the span of @base. */ struct resource *alloc_free_mem_region(struct resource *base, unsigned long size, unsigned long align, const char *name) { … } EXPORT_SYMBOL_NS_GPL(…); #endif /* CONFIG_GET_FREE_REGION */ static int __init strict_iomem(char *str) { … } static int iomem_fs_init_fs_context(struct fs_context *fc) { … } static struct file_system_type iomem_fs_type = …; static int __init iomem_init_inode(void) { … } fs_initcall(iomem_init_inode); __setup(…);
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