diff options
Diffstat (limited to 'drivers/iommu/ioasid.c')
-rw-r--r-- | drivers/iommu/ioasid.c | 422 |
1 files changed, 0 insertions, 422 deletions
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c deleted file mode 100644 index a786c034907c..000000000000 --- a/drivers/iommu/ioasid.c +++ /dev/null @@ -1,422 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * I/O Address Space ID allocator. There is one global IOASID space, split into - * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and - * free IOASIDs with ioasid_alloc() and ioasid_free(). - */ -#include <linux/ioasid.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/spinlock.h> -#include <linux/xarray.h> - -struct ioasid_data { - ioasid_t id; - struct ioasid_set *set; - void *private; - struct rcu_head rcu; -}; - -/* - * struct ioasid_allocator_data - Internal data structure to hold information - * about an allocator. There are two types of allocators: - * - * - Default allocator always has its own XArray to track the IOASIDs allocated. - * - Custom allocators may share allocation helpers with different private data. - * Custom allocators that share the same helper functions also share the same - * XArray. - * Rules: - * 1. Default allocator is always available, not dynamically registered. This is - * to prevent race conditions with early boot code that want to register - * custom allocators or allocate IOASIDs. - * 2. Custom allocators take precedence over the default allocator. - * 3. When all custom allocators sharing the same helper functions are - * unregistered (e.g. due to hotplug), all outstanding IOASIDs must be - * freed. Otherwise, outstanding IOASIDs will be lost and orphaned. - * 4. When switching between custom allocators sharing the same helper - * functions, outstanding IOASIDs are preserved. - * 5. When switching between custom allocator and default allocator, all IOASIDs - * must be freed to ensure unadulterated space for the new allocator. - * - * @ops: allocator helper functions and its data - * @list: registered custom allocators - * @slist: allocators share the same ops but different data - * @flags: attributes of the allocator - * @xa: xarray holds the IOASID space - * @rcu: used for kfree_rcu when unregistering allocator - */ -struct ioasid_allocator_data { - struct ioasid_allocator_ops *ops; - struct list_head list; - struct list_head slist; -#define IOASID_ALLOCATOR_CUSTOM BIT(0) /* Needs framework to track results */ - unsigned long flags; - struct xarray xa; - struct rcu_head rcu; -}; - -static DEFINE_SPINLOCK(ioasid_allocator_lock); -static LIST_HEAD(allocators_list); - -static ioasid_t default_alloc(ioasid_t min, ioasid_t max, void *opaque); -static void default_free(ioasid_t ioasid, void *opaque); - -static struct ioasid_allocator_ops default_ops = { - .alloc = default_alloc, - .free = default_free, -}; - -static struct ioasid_allocator_data default_allocator = { - .ops = &default_ops, - .flags = 0, - .xa = XARRAY_INIT(ioasid_xa, XA_FLAGS_ALLOC), -}; - -static struct ioasid_allocator_data *active_allocator = &default_allocator; - -static ioasid_t default_alloc(ioasid_t min, ioasid_t max, void *opaque) -{ - ioasid_t id; - - if (xa_alloc(&default_allocator.xa, &id, opaque, XA_LIMIT(min, max), GFP_ATOMIC)) { - pr_err("Failed to alloc ioasid from %d to %d\n", min, max); - return INVALID_IOASID; - } - - return id; -} - -static void default_free(ioasid_t ioasid, void *opaque) -{ - struct ioasid_data *ioasid_data; - - ioasid_data = xa_erase(&default_allocator.xa, ioasid); - kfree_rcu(ioasid_data, rcu); -} - -/* Allocate and initialize a new custom allocator with its helper functions */ -static struct ioasid_allocator_data *ioasid_alloc_allocator(struct ioasid_allocator_ops *ops) -{ - struct ioasid_allocator_data *ia_data; - - ia_data = kzalloc(sizeof(*ia_data), GFP_ATOMIC); - if (!ia_data) - return NULL; - - xa_init_flags(&ia_data->xa, XA_FLAGS_ALLOC); - INIT_LIST_HEAD(&ia_data->slist); - ia_data->flags |= IOASID_ALLOCATOR_CUSTOM; - ia_data->ops = ops; - - /* For tracking custom allocators that share the same ops */ - list_add_tail(&ops->list, &ia_data->slist); - - return ia_data; -} - -static bool use_same_ops(struct ioasid_allocator_ops *a, struct ioasid_allocator_ops *b) -{ - return (a->free == b->free) && (a->alloc == b->alloc); -} - -/** - * ioasid_register_allocator - register a custom allocator - * @ops: the custom allocator ops to be registered - * - * Custom allocators take precedence over the default xarray based allocator. - * Private data associated with the IOASID allocated by the custom allocators - * are managed by IOASID framework similar to data stored in xa by default - * allocator. - * - * There can be multiple allocators registered but only one is active. In case - * of runtime removal of a custom allocator, the next one is activated based - * on the registration ordering. - * - * Multiple allocators can share the same alloc() function, in this case the - * IOASID space is shared. - */ -int ioasid_register_allocator(struct ioasid_allocator_ops *ops) -{ - struct ioasid_allocator_data *ia_data; - struct ioasid_allocator_data *pallocator; - int ret = 0; - - spin_lock(&ioasid_allocator_lock); - - ia_data = ioasid_alloc_allocator(ops); - if (!ia_data) { - ret = -ENOMEM; - goto out_unlock; - } - - /* - * No particular preference, we activate the first one and keep - * the later registered allocators in a list in case the first one gets - * removed due to hotplug. - */ - if (list_empty(&allocators_list)) { - WARN_ON(active_allocator != &default_allocator); - /* Use this new allocator if default is not active */ - if (xa_empty(&active_allocator->xa)) { - rcu_assign_pointer(active_allocator, ia_data); - list_add_tail(&ia_data->list, &allocators_list); - goto out_unlock; - } - pr_warn("Default allocator active with outstanding IOASID\n"); - ret = -EAGAIN; - goto out_free; - } - - /* Check if the allocator is already registered */ - list_for_each_entry(pallocator, &allocators_list, list) { - if (pallocator->ops == ops) { - pr_err("IOASID allocator already registered\n"); - ret = -EEXIST; - goto out_free; - } else if (use_same_ops(pallocator->ops, ops)) { - /* - * If the new allocator shares the same ops, - * then they will share the same IOASID space. - * We should put them under the same xarray. - */ - list_add_tail(&ops->list, &pallocator->slist); - goto out_free; - } - } - list_add_tail(&ia_data->list, &allocators_list); - - spin_unlock(&ioasid_allocator_lock); - return 0; -out_free: - kfree(ia_data); -out_unlock: - spin_unlock(&ioasid_allocator_lock); - return ret; -} -EXPORT_SYMBOL_GPL(ioasid_register_allocator); - -/** - * ioasid_unregister_allocator - Remove a custom IOASID allocator ops - * @ops: the custom allocator to be removed - * - * Remove an allocator from the list, activate the next allocator in - * the order it was registered. Or revert to default allocator if all - * custom allocators are unregistered without outstanding IOASIDs. - */ -void ioasid_unregister_allocator(struct ioasid_allocator_ops *ops) -{ - struct ioasid_allocator_data *pallocator; - struct ioasid_allocator_ops *sops; - - spin_lock(&ioasid_allocator_lock); - if (list_empty(&allocators_list)) { - pr_warn("No custom IOASID allocators active!\n"); - goto exit_unlock; - } - - list_for_each_entry(pallocator, &allocators_list, list) { - if (!use_same_ops(pallocator->ops, ops)) - continue; - - if (list_is_singular(&pallocator->slist)) { - /* No shared helper functions */ - list_del(&pallocator->list); - /* - * All IOASIDs should have been freed before - * the last allocator that shares the same ops - * is unregistered. - */ - WARN_ON(!xa_empty(&pallocator->xa)); - if (list_empty(&allocators_list)) { - pr_info("No custom IOASID allocators, switch to default.\n"); - rcu_assign_pointer(active_allocator, &default_allocator); - } else if (pallocator == active_allocator) { - rcu_assign_pointer(active_allocator, - list_first_entry(&allocators_list, - struct ioasid_allocator_data, list)); - pr_info("IOASID allocator changed"); - } - kfree_rcu(pallocator, rcu); - break; - } - /* - * Find the matching shared ops to delete, - * but keep outstanding IOASIDs - */ - list_for_each_entry(sops, &pallocator->slist, list) { - if (sops == ops) { - list_del(&ops->list); - break; - } - } - break; - } - -exit_unlock: - spin_unlock(&ioasid_allocator_lock); -} -EXPORT_SYMBOL_GPL(ioasid_unregister_allocator); - -/** - * ioasid_set_data - Set private data for an allocated ioasid - * @ioasid: the ID to set data - * @data: the private data - * - * For IOASID that is already allocated, private data can be set - * via this API. Future lookup can be done via ioasid_find. - */ -int ioasid_set_data(ioasid_t ioasid, void *data) -{ - struct ioasid_data *ioasid_data; - int ret = 0; - - spin_lock(&ioasid_allocator_lock); - ioasid_data = xa_load(&active_allocator->xa, ioasid); - if (ioasid_data) - rcu_assign_pointer(ioasid_data->private, data); - else - ret = -ENOENT; - spin_unlock(&ioasid_allocator_lock); - - /* - * Wait for readers to stop accessing the old private data, so the - * caller can free it. - */ - if (!ret) - synchronize_rcu(); - - return ret; -} -EXPORT_SYMBOL_GPL(ioasid_set_data); - -/** - * ioasid_alloc - Allocate an IOASID - * @set: the IOASID set - * @min: the minimum ID (inclusive) - * @max: the maximum ID (inclusive) - * @private: data private to the caller - * - * Allocate an ID between @min and @max. The @private pointer is stored - * internally and can be retrieved with ioasid_find(). - * - * Return: the allocated ID on success, or %INVALID_IOASID on failure. - */ -ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, - void *private) -{ - struct ioasid_data *data; - void *adata; - ioasid_t id; - - data = kzalloc(sizeof(*data), GFP_ATOMIC); - if (!data) - return INVALID_IOASID; - - data->set = set; - data->private = private; - - /* - * Custom allocator needs allocator data to perform platform specific - * operations. - */ - spin_lock(&ioasid_allocator_lock); - adata = active_allocator->flags & IOASID_ALLOCATOR_CUSTOM ? active_allocator->ops->pdata : data; - id = active_allocator->ops->alloc(min, max, adata); - if (id == INVALID_IOASID) { - pr_err("Failed ASID allocation %lu\n", active_allocator->flags); - goto exit_free; - } - - if ((active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) && - xa_alloc(&active_allocator->xa, &id, data, XA_LIMIT(id, id), GFP_ATOMIC)) { - /* Custom allocator needs framework to store and track allocation results */ - pr_err("Failed to alloc ioasid from %d\n", id); - active_allocator->ops->free(id, active_allocator->ops->pdata); - goto exit_free; - } - data->id = id; - - spin_unlock(&ioasid_allocator_lock); - return id; -exit_free: - spin_unlock(&ioasid_allocator_lock); - kfree(data); - return INVALID_IOASID; -} -EXPORT_SYMBOL_GPL(ioasid_alloc); - -/** - * ioasid_free - Free an ioasid - * @ioasid: the ID to remove - */ -void ioasid_free(ioasid_t ioasid) -{ - struct ioasid_data *ioasid_data; - - spin_lock(&ioasid_allocator_lock); - ioasid_data = xa_load(&active_allocator->xa, ioasid); - if (!ioasid_data) { - pr_err("Trying to free unknown IOASID %u\n", ioasid); - goto exit_unlock; - } - - active_allocator->ops->free(ioasid, active_allocator->ops->pdata); - /* Custom allocator needs additional steps to free the xa element */ - if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) { - ioasid_data = xa_erase(&active_allocator->xa, ioasid); - kfree_rcu(ioasid_data, rcu); - } - -exit_unlock: - spin_unlock(&ioasid_allocator_lock); -} -EXPORT_SYMBOL_GPL(ioasid_free); - -/** - * ioasid_find - Find IOASID data - * @set: the IOASID set - * @ioasid: the IOASID to find - * @getter: function to call on the found object - * - * The optional getter function allows to take a reference to the found object - * under the rcu lock. The function can also check if the object is still valid: - * if @getter returns false, then the object is invalid and NULL is returned. - * - * If the IOASID exists, return the private pointer passed to ioasid_alloc. - * Private data can be NULL if not set. Return an error if the IOASID is not - * found, or if @set is not NULL and the IOASID does not belong to the set. - */ -void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, - bool (*getter)(void *)) -{ - void *priv; - struct ioasid_data *ioasid_data; - struct ioasid_allocator_data *idata; - - rcu_read_lock(); - idata = rcu_dereference(active_allocator); - ioasid_data = xa_load(&idata->xa, ioasid); - if (!ioasid_data) { - priv = ERR_PTR(-ENOENT); - goto unlock; - } - if (set && ioasid_data->set != set) { - /* data found but does not belong to the set */ - priv = ERR_PTR(-EACCES); - goto unlock; - } - /* Now IOASID and its set is verified, we can return the private data */ - priv = rcu_dereference(ioasid_data->private); - if (getter && !getter(priv)) - priv = NULL; -unlock: - rcu_read_unlock(); - - return priv; -} -EXPORT_SYMBOL_GPL(ioasid_find); - -MODULE_AUTHOR("Jean-Philippe Brucker <jean-philippe.brucker@arm.com>"); -MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>"); -MODULE_DESCRIPTION("IO Address Space ID (IOASID) allocator"); -MODULE_LICENSE("GPL"); |