/* $NetBSD: drm_vma_manager.h,v 1.2 2018/08/27 04:58:38 riastradh Exp $ */
#ifndef __DRM_VMA_MANAGER_H__
#define __DRM_VMA_MANAGER_H__
/*
* Copyright (c) 2013 David Herrmann <dh.herrmann@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <drm/drm_mm.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/rbtree.h>
#include <linux/spinlock.h>
#include <linux/types.h>
struct drm_vma_offset_file {
struct rb_node vm_rb;
struct file *vm_filp;
unsigned long vm_count;
};
struct drm_vma_offset_node {
rwlock_t vm_lock;
struct drm_mm_node vm_node;
struct rb_node vm_rb;
struct rb_root vm_files;
};
struct drm_vma_offset_manager {
rwlock_t vm_lock;
struct rb_root vm_addr_space_rb;
struct drm_mm vm_addr_space_mm;
};
void drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr,
unsigned long page_offset, unsigned long size);
void drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr);
struct drm_vma_offset_node *drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr,
unsigned long start,
unsigned long pages);
int drm_vma_offset_add(struct drm_vma_offset_manager *mgr,
struct drm_vma_offset_node *node, unsigned long pages);
void drm_vma_offset_remove(struct drm_vma_offset_manager *mgr,
struct drm_vma_offset_node *node);
int drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *filp);
void drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *filp);
bool drm_vma_node_is_allowed(struct drm_vma_offset_node *node,
struct file *filp);
/**
* drm_vma_offset_exact_lookup_locked() - Look up node by exact address
* @mgr: Manager object
* @start: Start address (page-based, not byte-based)
* @pages: Size of object (page-based)
*
* Same as drm_vma_offset_lookup_locked() but does not allow any offset into the node.
* It only returns the exact object with the given start address.
*
* RETURNS:
* Node at exact start address @start.
*/
static inline struct drm_vma_offset_node *
drm_vma_offset_exact_lookup_locked(struct drm_vma_offset_manager *mgr,
unsigned long start,
unsigned long pages)
{
struct drm_vma_offset_node *node;
node = drm_vma_offset_lookup_locked(mgr, start, pages);
return (node && node->vm_node.start == start) ? node : NULL;
}
/**
* drm_vma_offset_lock_lookup() - Lock lookup for extended private use
* @mgr: Manager object
*
* Lock VMA manager for extended lookups. Only locked VMA function calls
* are allowed while holding this lock. All other contexts are blocked from VMA
* until the lock is released via drm_vma_offset_unlock_lookup().
*
* Use this if you need to take a reference to the objects returned by
* drm_vma_offset_lookup_locked() before releasing this lock again.
*
* This lock must not be used for anything else than extended lookups. You must
* not call any other VMA helpers while holding this lock.
*
* Note: You're in atomic-context while holding this lock!
*/
static inline void drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr)
{
read_lock(&mgr->vm_lock);
}
/**
* drm_vma_offset_unlock_lookup() - Unlock lookup for extended private use
* @mgr: Manager object
*
* Release lookup-lock. See drm_vma_offset_lock_lookup() for more information.
*/
static inline void drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr)
{
read_unlock(&mgr->vm_lock);
}
/**
* drm_vma_node_reset() - Initialize or reset node object
* @node: Node to initialize or reset
*
* Reset a node to its initial state. This must be called before using it with
* any VMA offset manager.
*
* This must not be called on an already allocated node, or you will leak
* memory.
*/
static inline void drm_vma_node_reset(struct drm_vma_offset_node *node)
{
memset(node, 0, sizeof(*node));
node->vm_files = RB_ROOT;
rwlock_init(&node->vm_lock);
}
/**
* drm_vma_node_start() - Return start address for page-based addressing
* @node: Node to inspect
*
* Return the start address of the given node. This can be used as offset into
* the linear VM space that is provided by the VMA offset manager. Note that
* this can only be used for page-based addressing. If you need a proper offset
* for user-space mappings, you must apply "<< PAGE_SHIFT" or use the
* drm_vma_node_offset_addr() helper instead.
*
* RETURNS:
* Start address of @node for page-based addressing. 0 if the node does not
* have an offset allocated.
*/
static inline unsigned long drm_vma_node_start(struct drm_vma_offset_node *node)
{
return node->vm_node.start;
}
/**
* drm_vma_node_size() - Return size (page-based)
* @node: Node to inspect
*
* Return the size as number of pages for the given node. This is the same size
* that was passed to drm_vma_offset_add(). If no offset is allocated for the
* node, this is 0.
*
* RETURNS:
* Size of @node as number of pages. 0 if the node does not have an offset
* allocated.
*/
static inline unsigned long drm_vma_node_size(struct drm_vma_offset_node *node)
{
return node->vm_node.size;
}
/**
* drm_vma_node_has_offset() - Check whether node is added to offset manager
* @node: Node to be checked
*
* RETURNS:
* true iff the node was previously allocated an offset and added to
* an vma offset manager.
*/
static inline bool drm_vma_node_has_offset(struct drm_vma_offset_node *node)
{
return drm_mm_node_allocated(&node->vm_node);
}
/**
* drm_vma_node_offset_addr() - Return sanitized offset for user-space mmaps
* @node: Linked offset node
*
* Same as drm_vma_node_start() but returns the address as a valid offset that
* can be used for user-space mappings during mmap().
* This must not be called on unlinked nodes.
*
* RETURNS:
* Offset of @node for byte-based addressing. 0 if the node does not have an
* object allocated.
*/
static inline __u64 drm_vma_node_offset_addr(struct drm_vma_offset_node *node)
{
return ((__u64)node->vm_node.start) << PAGE_SHIFT;
}
/**
* drm_vma_node_unmap() - Unmap offset node
* @node: Offset node
* @file_mapping: Address space to unmap @node from
*
* Unmap all userspace mappings for a given offset node. The mappings must be
* associated with the @file_mapping address-space. If no offset exists
* nothing is done.
*
* This call is unlocked. The caller must guarantee that drm_vma_offset_remove()
* is not called on this node concurrently.
*/
static inline void drm_vma_node_unmap(struct drm_vma_offset_node *node,
struct address_space *file_mapping)
{
if (drm_vma_node_has_offset(node))
unmap_mapping_range(file_mapping,
drm_vma_node_offset_addr(node),
drm_vma_node_size(node) << PAGE_SHIFT, 1);
}
/**
* drm_vma_node_verify_access() - Access verification helper for TTM
* @node: Offset node
* @filp: Open-file
*
* This checks whether @filp is granted access to @node. It is the same as
* drm_vma_node_is_allowed() but suitable as drop-in helper for TTM
* verify_access() callbacks.
*
* RETURNS:
* 0 if access is granted, -EACCES otherwise.
*/
static inline int drm_vma_node_verify_access(struct drm_vma_offset_node *node,
struct file *filp)
{
return drm_vma_node_is_allowed(node, filp) ? 0 : -EACCES;
}
#endif /* __DRM_VMA_MANAGER_H__ */