path: root/drivers/gpu/drm/drm_bufs.c

/*
 * Legacy: Generic DRM Buffer Management
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Author: Rickard E. (Rik) Faith <faith@valinux.com>
 * Author: Gareth Hughes <gareth@valinux.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 (including the next
 * paragraph) 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
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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 <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/export.h>
#include <asm/shmparam.h>
#include <drm/drmP.h>
#include "drm_legacy.h"

static struct drm_map_list *drm_find_matching_map(struct drm_device *dev,
						  struct drm_local_map *map)
{
	struct drm_map_list *entry;
	list_for_each_entry(entry, &dev->maplist, head) {
		/*
		 * Because the kernel-userspace ABI is fixed at a 32-bit offset
		 * while PCI resources may live above that, we only compare the
		 * lower 32 bits of the map offset for maps of type
		 * _DRM_FRAMEBUFFER or _DRM_REGISTERS.
		 * It is assumed that if a driver have more than one resource
		 * of each type, the lower 32 bits are different.
		 */
		if (!entry->map ||
		    map->type != entry->map->type ||
		    entry->master != dev->master)
			continue;
		switch (map->type) {
		case _DRM_SHM:
			if (map->flags != _DRM_CONTAINS_LOCK)
				break;
			return entry;
		case _DRM_REGISTERS:
		case _DRM_FRAME_BUFFER:
			if ((entry->map->offset & 0xffffffff) ==
			    (map->offset & 0xffffffff))
				return entry;
		default: /* Make gcc happy */
			;
		}
		if (entry->map->offset == map->offset)
			return entry;
	}

	return NULL;
}

static int drm_map_handle(struct drm_device *dev, struct drm_hash_item *hash,
			  unsigned long user_token, int hashed_handle, int shm)
{
	int use_hashed_handle, shift;
	unsigned long add;

#if (BITS_PER_LONG == 64)
	use_hashed_handle = ((user_token & 0xFFFFFFFF00000000UL) || hashed_handle);
#elif (BITS_PER_LONG == 32)
	use_hashed_handle = hashed_handle;
#else
#error Unsupported long size. Neither 64 nor 32 bits.
#endif

	if (!use_hashed_handle) {
		int ret;
		hash->key = user_token >> PAGE_SHIFT;
		ret = drm_ht_insert_item(&dev->map_hash, hash);
		if (ret != -EINVAL)
			return ret;
	}

	shift = 0;
	add = DRM_MAP_HASH_OFFSET >> PAGE_SHIFT;
	if (shm && (SHMLBA > PAGE_SIZE)) {
		int bits = ilog2(SHMLBA >> PAGE_SHIFT) + 1;

		/* For shared memory, we have to preserve the SHMLBA
		 * bits of the eventual vma->vm_pgoff value during
		 * mmap().  Otherwise we run into cache aliasing problems
		 * on some platforms.  On these platforms, the pgoff of
		 * a mmap() request is used to pick a suitable virtual
		 * address for the mmap() region such that it will not
		 * cause cache aliasing problems.
		 *
		 * Therefore, make sure the SHMLBA relevant bits of the
		 * hash value we use are equal to those in the original
		 * kernel virtual address.
		 */
		shift = bits;
		add |= ((user_token >> PAGE_SHIFT) & ((1UL << bits) - 1UL));
	}

	return drm_ht_just_insert_please(&dev->map_hash, hash,
					 user_token, 32 - PAGE_SHIFT - 3,
					 shift, add);
}

/**
 * Core function to create a range of memory available for mapping by a
 * non-root process.
 *
 * Adjusts the memory offset to its absolute value according to the mapping
 * type.  Adds the map to the map list drm_device::maplist. Adds MTRR's where
 * applicable and if supported by the kernel.
 */
static int drm_addmap_core(struct drm_device * dev, resource_size_t offset,
			   unsigned int size, enum drm_map_type type,
			   enum drm_map_flags flags,
			   struct drm_map_list ** maplist)
{
	struct drm_local_map *map;
	struct drm_map_list *list;
	drm_dma_handle_t *dmah;
	unsigned long user_token;
	int ret;

	map = kmalloc(sizeof(*map), GFP_KERNEL);
	if (!map)
		return -ENOMEM;

	map->offset = offset;
	map->size = size;
	map->flags = flags;
	map->type = type;

	/* Only allow shared memory to be removable since we only keep enough
	 * book keeping information about shared memory to allow for removal
	 * when processes fork.
	 */
	if ((map->flags & _DRM_REMOVABLE) && map->type != _DRM_SHM) {
		kfree(map);
		return -EINVAL;
	}
	DRM_DEBUG("offset = 0x%08llx, size = 0x%08lx, type = %d\n",
		  (unsigned long long)map->offset, map->size, map->type);

	/* page-align _DRM_SHM maps. They are allocated here so there is no security
	 * hole created by that and it works around various broken drivers that use
	 * a non-aligned quantity to map the SAREA. --BenH
	 */
	if (map->type == _DRM_SHM)
		map->size = PAGE_ALIGN(map->size);

	if ((map->offset & (~(resource_size_t)PAGE_MASK)) || (map->size & (~PAGE_MASK))) {
		kfree(map);
		return -EINVAL;
	}
	map->mtrr = -1;
	map->handle = NULL;

	switch (map->type) {
	case _DRM_REGISTERS:
	case _DRM_FRAME_BUFFER:
#if !defined(__sparc__) && !defined(__alpha__) && !defined(__ia64__) && !defined(__powerpc64__) && !defined(__x86_64__) && !defined(__arm__)
		if (map->offset + (map->size-1) < map->offset ||
		    map->offset < virt_to_phys(high_memory)) {
			kfree(map);
			return -EINVAL;
		}
#endif
		/* Some drivers preinitialize some maps, without the X Server
		 * needing to be aware of it.  Therefore, we just return success
		 * when the server tries to create a duplicate map.
		 */
		list = drm_find_matching_map(dev, map);
		if (list != NULL) {
			if