Release 4.15 kernel/resource.c

/*
 *      linux/kernel/resource.c
 *
 * Copyright (C) 1999   Linus Torvalds
 * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
 *
 * Arbitrary resource management.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " 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/sched.h>
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/resource_ext.h>
#include <asm/io.h>



struct resource ioport_resource = {
	.name	= "PCI IO",
	.start	= 0,
	.end	= IO_SPACE_LIMIT,
	.flags	= IORESOURCE_IO,
};

EXPORT_SYMBOL(ioport_resource);


struct resource iomem_resource = {
	.name	= "PCI mem",
	.start	= 0,
	.end	= -1,
	.flags	= IORESOURCE_MEM,
};

EXPORT_SYMBOL(iomem_resource);

/* constraints to be met while allocating resources */

struct resource_constraint {
	


resource_size_t min, max, align;
	
resource_size_t (*alignf)(void *, const struct resource *,
			resource_size_t, resource_size_t);
	
void *alignf_data;
};

static DEFINE_RWLOCK(resource_lock);

/*
 * For memory hotplug, there is no way to free resource entries allocated
 * by boot mem after the system is up. So for reusing the resource entry
 * we need to remember the resource.
 */

static struct resource *bootmem_resource_free;
static DEFINE_SPINLOCK(bootmem_resource_lock);



static struct resource *next_resource(struct resource *p, bool sibling_only)
{
	/* Caller wants to traverse through siblings only */
	if (sibling_only)
		return p->sibling;

	if (p->child)
		return p->child;
	while (!p->sibling && p->parent)
		p = p->parent;
	return p->sibling;
}

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static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
	struct resource *p = v;
	(*pos)++;
	return (void *)next_resource(p, false);
}

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#ifdef CONFIG_PROC_FS


enum { MAX_IORES_LEVEL = 5 };


static void *r_start(struct seq_file *m, loff_t *pos)
	
__acquires(resource_lock)
{
	struct resource *p = m->private;
	loff_t l = 0;
	read_lock(&resource_lock);
	for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
		;
	return p;
}

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static void r_stop(struct seq_file *m, void *v)
	
__releases(resource_lock)
{
	read_unlock(&resource_lock);
}

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static int r_show(struct seq_file *m, void *v)
{
	struct resource *root = m->private;
	struct resource *r = v, *p;
	unsigned long long start, end;
	int width = root->end < 0x10000 ? 4 : 8;
	int depth;

	for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
		if (p->parent == root)
			break;

	if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
		start = r->start;
		end = r->end;
	} else {
		start = end = 0;
	}

	seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
			depth * 2, "",
			width, start,
			width, end,
			r->name ? r->name : "<BAD>");
	return 0;
}

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static const struct seq_operations resource_op = {
	.start	= r_start,
	.next	= r_next,
	.stop	= r_stop,
	.show	= r_show,
};



static int ioports_open(struct inode *inode, struct file *file)
{
	int res = seq_open(file, &resource_op);
	if (!res) {
		struct seq_file *m = file->private_data;
		m->private = &ioport_resource;
	}
	return res;
}

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static int iomem_open(struct inode *inode, struct file *file)
{
	int res = seq_open(file, &resource_op);
	if (!res) {
		struct seq_file *m = file->private_data;
		m->private = &iomem_resource;
	}
	return res;
}

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static const struct file_operations proc_ioports_operations = {
	.open		= ioports_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};


static const struct file_operations proc_iomem_operations = {
	.open		= iomem_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};



static int __init ioresources_init(void)
{
	proc_create("ioports", 0, NULL, &proc_ioports_operations);
	proc_create("iomem", 0, NULL, &proc_iomem_operations);
	return 0;
}
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__initcall(ioresources_init);

#endif /* CONFIG_PROC_FS */



static void free_resource(struct resource *res)
{
	if (!res)
		return;

	if (!PageSlab(virt_to_head_page(res))) {
		spin_lock(&bootmem_resource_lock);
		res->sibling = bootmem_resource_free;
		bootmem_resource_free = res;
		spin_unlock(&bootmem_resource_lock);
	} else {
		kfree(res);
	}
}

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static struct resource *alloc_resource(gfp_t flags)
{
	struct resource *res = NULL;

	spin_lock(&bootmem_resource_lock);
	if (bootmem_resource_free) {
		res = bootmem_resource_free;
		bootmem_resource_free = res->sibling;
	}
	spin_unlock(&bootmem_resource_lock);

	if (res)
		memset(res, 0, sizeof(struct resource));
	else
		res = kzalloc(sizeof(struct resource), flags);

	return res;
}

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/* Return the conflict entry if you can't request it */


static struct resource * __request_resource(struct resource *root, struct resource *new)
{
	resource_size_t start = new->start;
	resource_size_t end = new->end;
	struct resource *tmp, **p;

	if (end < start)
		return root;
	if (start < root->start)
		return root;
	if (end > root->end)
		return root;
	p = &root->child;
	for (;;) {
		tmp = *p;
		if (!tmp || tmp->start > end) {
			new->sibling = tmp;
			*p = new;
			new->parent = root;
			return NULL;
		}
		p = &tmp->sibling;
		if (tmp->end < start)
			continue;
		return tmp;
	}
}

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static int __release_resource(struct resource *old, bool release_child)
{
	struct resource *tmp, **p, *chd;

	p = &old->parent->child;
	for (;;) {
		tmp = *p;
		if (!tmp)
			break;
		if (tmp == old) {
			if (release_child || !(tmp->child)) {
				*p = tmp->sibling;
			} else {
				for (chd = tmp->child;; chd = chd->sibling) {
					chd->parent = tmp->parent;
					if (!(chd->sibling))
						break;
				}
				*p = tmp->child;
				chd->sibling = tmp->sibling;
			}
			old->parent = NULL;
			return 0;
		}
		p = &tmp->sibling;
	}
	return -EINVAL;
}

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static void __release_child_resources(struct resource *r)
{
	struct resource *tmp, *p;
	resource_size_t size;

	p = r->child;
	r->child = NULL;
	while (p) {
		tmp = p;
		p = p->sibling;

		tmp->parent = NULL;
		tmp->sibling = NULL;
		__release_child_resources(tmp);

		printk(KERN_DEBUG "release child resource %pR\n", tmp);
		/* need to restore size, and keep flags */
		size = resource_size(tmp);
		tmp->start = 0;
		tmp->end = size - 1;
	}
}

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void release_child_resources(struct resource *r)
{
	write_lock(&resource_lock);
	__release_child_resources(r);
	write_unlock(&resource_lock);
}

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/**
 * 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)
{
	struct resource *conflict;

	write_lock(&resource_lock);
	conflict = __request_resource(root, new);
	write_unlock(&resource_lock);
	return conflict;
}

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/**
 * 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)
{
	struct resource *conflict;

	conflict = request_resource_conflict(root, new);
	return conflict ? -EBUSY : 0;
}

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EXPORT_SYMBOL(request_resource);

/**
 * release_resource - release a previously reserved resource
 * @old: resource pointer
 */


int release_resource(struct resource *old)
{
	int retval;

	write_lock(&resource_lock);
	retval = __release_resource(old, true);
	write_unlock(&resource_lock);
	return retval;
}

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EXPORT_SYMBOL(release_resource);

/*
 * Finds the lowest iomem resource existing within [res->start.res->end).
 * The caller must specify res->start, res->end, res->flags, and optionally
 * desc.  If found, returns 0, res is overwritten, if not found, returns -1.
 * This function walks the whole tree and not just first level children until
 * and unless first_level_children_only is true.
 */


static int find_next_iomem_res(struct resource *res, unsigned long desc,
			       bool first_level_children_only)
{
	resource_size_t start, end;
	struct resource *p;
	bool sibling_only = false;

	BUG_ON(!res);

	start = res->start;
	end = res->end;
	BUG_ON(start >= end);

	if (first_level_children_only)
		sibling_only = true;

	read_lock(&resource_lock);

	for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
		if ((p->flags & res->flags) != res->flags)
			continue;
		if ((desc != IORES_DESC_NONE) && (desc != p->desc))
			continue;
		if (p->start > end) {
			p = NULL;
			break;
		}
		if ((p->end >= start) && (p->start < end))
			break;
	}

	read_unlock(&resource_lock);
	if (!p)
		return -1;
	/* copy data */
	if (res->start < p->start)
		res->start = p->start;
	if (res->end > p->end)
		res->end = p->end;
	res->flags = p->flags;
	res->desc = p->desc;
	return 0;
}

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Vivek Goyal
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static int __walk_iomem_res_desc(struct resource *res, unsigned long desc,
				 bool first_level_children_only,
				 void *arg,
				 int (*func)(struct resource *, void *))
{
	u64 orig_end = res->end;
	int ret = -1;

	while ((res->start < res->end) &&
	       !find_next_iomem_res(res, desc, first_level_children_only)) {
		ret = (*func)(res, arg);
		if (ret)
			break;

		res->start = res->end + 1;
		res->end = orig_end;
	}

	return ret;
}

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/*
 * Walks through iomem resources and calls func() with matching resource
 * ranges. This walks through whole tree and not just first level children.
 * All the memory ranges which overlap start,end and also match flags and
 * desc are valid candidates.
 *
 * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
 * @flags: I/O resource flags
 * @start: start addr
 * @end: end addr
 *
 * 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 *))
{
	struct resource res;

	res.start = start;
	res.end = end;
	res.flags = flags;

	return __walk_iomem_res_desc(&res, desc, false, arg, func);
}

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/*
 * 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 *))
{
	struct resource res;

	res.start = start;
	res.end = end;
	res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;

	return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true,
				     arg, func);
}

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/*
 * 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 *))
{
	struct resource res;

	res.start = start;
	res.end = end;
	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;

	return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true,
				     arg, func);
}

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#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)

/*
 * 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 *))
{
	struct resource res;
	unsigned long pfn, end_pfn;
	u64 orig_end;
	int ret = -1;

	res.start = (u64) start_pfn << PAGE_SHIFT;
	res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
	res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
	orig_end = res.end;
	while ((res.start < res.end) &&
		(find_next_iomem_res(&res, IORES_DESC_NONE, true) >= 0)) {
		pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
		end_pfn = (res.end + 1) >> PAGE_SHIFT;
		if (end_pfn > pfn)
			ret = (*func)(pfn, end_pfn - pfn, arg);
		if (ret)
			break;
		res.start = res.end + 1;
		res.end = orig_end;
	}
	return ret;
}

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#endif



static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
{
	return 1;
}

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/*
 * 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)
{
	return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
}
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EXPORT_SYMBOL_GPL(page_is_ram);

/**
 * 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)
{
	resource_size_t end = start + size - 1;
	int type = 0; int other = 0;
	struct resource *p;

	read_lock(&resource_lock);
	for (p = iomem_resource.child; p ; p = p->sibling) {
		bool is_type = (((p->flags & flags) == flags) &&
				((desc == IORES_DESC_NONE) ||
				 (desc == p->desc)));

		if (start >= p->start && start <= p->end)
			is_type ? type++ : other++;
		if (end >= p->start && end <= p->end)
			is_type ? type++ : other++;
		if (p->start >= start && p->end <= end)
			is_type ? type++ : other++;
	}
	read_unlock(&resource_lock);

	if (other == 0)
		return type ? REGION_INTERSECTS : REGION_DISJOINT;

	if (type)
		return REGION_MIXED;

	return REGION_DISJOINT;
}
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EXPORT_SYMBOL_GPL(region_intersects);



void __weak arch_remove_reservations(struct resource *avail)
{
}

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Björn Helgaas
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static resource_size_t simple_align_resource(void *data,
					     const struct resource *avail,
					     resource_size_t size,
					     resource_size_t align)
{
	return avail->start;
}

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static void resource_clip(struct resource *res, resource_size_t min,
			  resource_size_t max)
{
	if (res->start < min)
		res->start = min;
	if (res->end > max)
		res->end = max;
}

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/*
 * Find empty slot in the resource tree with the given range and
 * alignment constraints
 */


static int __find_resource(struct resource *root, struct resource *old,
			 struct resource *new,
			 resource_size_t  size,
			 struct resource_constraint *constraint)
{
	struct resource *this = root->child;
	struct resource tmp = *new, avail, alloc;

	tmp.start = root->start;
	/*
         * Skip past an allocated resource that starts at 0, since the assignment
         * of this->start - 1 to tmp->end below would cause an underflow.
         */
	if (this && this->start == root->start) {
		tmp.start = (this == old) ? old->start : this->end + 1;
		this = this->sibling;
	}
	for(;;) {
		if (this)
			tmp.end = (this == old) ?  this->end : this->start - 1;
		else
			tmp.end = root->end;

		if (tmp.end < tmp.start)
			goto next;

		resource_clip(&tmp, constraint->min, constraint->max);
		arch_remove_reservations(&tmp);

		/* Check for overflow after ALIGN() */
		avail.start = ALIGN(tmp.start, constraint->align);
		avail.end = tmp.end;
		avail.flags = new->flags & ~IORESOURCE_UNSET;
		if (avail.start >= tmp