drm_vm.c

linux 内核源代码

	if (type)
		*type = VM_FAULT_MINOR;
	return drm_do_vm_nopage(vma, address);
}

static struct page *drm_vm_shm_nopage(struct vm_area_struct *vma,
				      unsigned long address, int *type)
{
	if (type)
		*type = VM_FAULT_MINOR;
	return drm_do_vm_shm_nopage(vma, address);
}

static struct page *drm_vm_dma_nopage(struct vm_area_struct *vma,
				      unsigned long address, int *type)
{
	if (type)
		*type = VM_FAULT_MINOR;
	return drm_do_vm_dma_nopage(vma, address);
}

static struct page *drm_vm_sg_nopage(struct vm_area_struct *vma,
				     unsigned long address, int *type)
{
	if (type)
		*type = VM_FAULT_MINOR;
	return drm_do_vm_sg_nopage(vma, address);
}

/** AGP virtual memory operations */
static struct vm_operations_struct drm_vm_ops = {
	.nopage = drm_vm_nopage,
	.open = drm_vm_open,
	.close = drm_vm_close,
};

/** Shared virtual memory operations */
static struct vm_operations_struct drm_vm_shm_ops = {
	.nopage = drm_vm_shm_nopage,
	.open = drm_vm_open,
	.close = drm_vm_shm_close,
};

/** DMA virtual memory operations */
static struct vm_operations_struct drm_vm_dma_ops = {
	.nopage = drm_vm_dma_nopage,
	.open = drm_vm_open,
	.close = drm_vm_close,
};

/** Scatter-gather virtual memory operations */
static struct vm_operations_struct drm_vm_sg_ops = {
	.nopage = drm_vm_sg_nopage,
	.open = drm_vm_open,
	.close = drm_vm_close,
};

/**
 * \c open method for shared virtual memory.
 *
 * \param vma virtual memory area.
 *
 * Create a new drm_vma_entry structure as the \p vma private data entry and
 * add it to drm_device::vmalist.
 */
static void drm_vm_open_locked(struct vm_area_struct *vma)
{
	struct drm_file *priv = vma->vm_file->private_data;
	struct drm_device *dev = priv->head->dev;
	struct drm_vma_entry *vma_entry;

	DRM_DEBUG("0x%08lx,0x%08lx\n",
		  vma->vm_start, vma->vm_end - vma->vm_start);
	atomic_inc(&dev->vma_count);

	vma_entry = drm_alloc(sizeof(*vma_entry), DRM_MEM_VMAS);
	if (vma_entry) {
		vma_entry->vma = vma;
		vma_entry->pid = current->pid;
		list_add(&vma_entry->head, &dev->vmalist);
	}
}

static void drm_vm_open(struct vm_area_struct *vma)
{
	struct drm_file *priv = vma->vm_file->private_data;
	struct drm_device *dev = priv->head->dev;

	mutex_lock(&dev->struct_mutex);
	drm_vm_open_locked(vma);
	mutex_unlock(&dev->struct_mutex);
}

/**
 * \c close method for all virtual memory types.
 *
 * \param vma virtual memory area.
 *
 * Search the \p vma private data entry in drm_device::vmalist, unlink it, and
 * free it.
 */
static void drm_vm_close(struct vm_area_struct *vma)
{
	struct drm_file *priv = vma->vm_file->private_data;
	struct drm_device *dev = priv->head->dev;
	struct drm_vma_entry *pt, *temp;

	DRM_DEBUG("0x%08lx,0x%08lx\n",
		  vma->vm_start, vma->vm_end - vma->vm_start);
	atomic_dec(&dev->vma_count);

	mutex_lock(&dev->struct_mutex);
	list_for_each_entry_safe(pt, temp, &dev->vmalist, head) {
		if (pt->vma == vma) {
			list_del(&pt->head);
			drm_free(pt, sizeof(*pt), DRM_MEM_VMAS);
			break;
		}
	}
	mutex_unlock(&dev->struct_mutex);
}

/**
 * mmap DMA memory.
 *
 * \param file_priv DRM file private.
 * \param vma virtual memory area.
 * \return zero on success or a negative number on failure.
 *
 * Sets the virtual memory area operations structure to vm_dma_ops, the file
 * pointer, and calls vm_open().
 */
static int drm_mmap_dma(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev;
	struct drm_device_dma *dma;
	unsigned long length = vma->vm_end - vma->vm_start;

	dev = priv->head->dev;
	dma = dev->dma;
	DRM_DEBUG("start = 0x%lx, end = 0x%lx, page offset = 0x%lx\n",
		  vma->vm_start, vma->vm_end, vma->vm_pgoff);

	/* Length must match exact page count */
	if (!dma || (length >> PAGE_SHIFT) != dma->page_count) {
		return -EINVAL;
	}

	if (!capable(CAP_SYS_ADMIN) &&
	    (dma->flags & _DRM_DMA_USE_PCI_RO)) {
		vma->vm_flags &= ~(VM_WRITE | VM_MAYWRITE);
#if defined(__i386__) || defined(__x86_64__)
		pgprot_val(vma->vm_page_prot) &= ~_PAGE_RW;
#else
		/* Ye gads this is ugly.  With more thought
		   we could move this up higher and use
		   `protection_map' instead.  */
		vma->vm_page_prot =
		    __pgprot(pte_val
			     (pte_wrprotect
			      (__pte(pgprot_val(vma->vm_page_prot)))));
#endif
	}

	vma->vm_ops = &drm_vm_dma_ops;

	vma->vm_flags |= VM_RESERVED;	/* Don't swap */
	vma->vm_flags |= VM_DONTEXPAND;

	vma->vm_file = filp;	/* Needed for drm_vm_open() */
	drm_vm_open_locked(vma);
	return 0;
}

unsigned long drm_core_get_map_ofs(struct drm_map * map)
{
	return map->offset;
}

EXPORT_SYMBOL(drm_core_get_map_ofs);

unsigned long drm_core_get_reg_ofs(struct drm_device *dev)
{
#ifdef __alpha__
	return dev->hose->dense_mem_base - dev->hose->mem_space->start;
#else
	return 0;
#endif
}

EXPORT_SYMBOL(drm_core_get_reg_ofs);

/**
 * mmap DMA memory.
 *
 * \param file_priv DRM file private.
 * \param vma virtual memory area.
 * \return zero on success or a negative number on failure.
 *
 * If the virtual memory area has no offset associated with it then it's a DMA
 * area, so calls mmap_dma(). Otherwise searches the map in drm_device::maplist,
 * checks that the restricted flag is not set, sets the virtual memory operations
 * according to the mapping type and remaps the pages. Finally sets the file
 * pointer and calls vm_open().
 */
static int drm_mmap_locked(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->head->dev;
	struct drm_map *map = NULL;
	unsigned long offset = 0;
	struct drm_hash_item *hash;

	DRM_DEBUG("start = 0x%lx, end = 0x%lx, page offset = 0x%lx\n",
		  vma->vm_start, vma->vm_end, vma->vm_pgoff);

	if (!priv->authenticated)
		return -EACCES;

	/* We check for "dma". On Apple's UniNorth, it's valid to have
	 * the AGP mapped at physical address 0
	 * --BenH.
	 */
	if (!vma->vm_pgoff
#if __OS_HAS_AGP
	    && (!dev->agp
		|| dev->agp->agp_info.device->vendor != PCI_VENDOR_ID_APPLE)
#endif
	    )
		return drm_mmap_dma(filp, vma);

	if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff, &hash)) {
		DRM_ERROR("Could not find map\n");
		return -EINVAL;
	}

	map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
	if (!map || ((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN)))
		return -EPERM;

	/* Check for valid size. */
	if (map->size < vma->vm_end - vma->vm_start)
		return -EINVAL;

	if (!capable(CAP_SYS_ADMIN) && (map->flags & _DRM_READ_ONLY)) {
		vma->vm_flags &= ~(VM_WRITE | VM_MAYWRITE);
#if defined(__i386__) || defined(__x86_64__)
		pgprot_val(vma->vm_page_prot) &= ~_PAGE_RW;
#else
		/* Ye gads this is ugly.  With more thought
		   we could move this up higher and use
		   `protection_map' instead.  */
		vma->vm_page_prot =
		    __pgprot(pte_val
			     (pte_wrprotect
			      (__pte(pgprot_val(vma->vm_page_prot)))));
#endif
	}

	switch (map->type) {
	case _DRM_AGP:
		if (drm_core_has_AGP(dev) && dev->agp->cant_use_aperture) {
			/*
			 * On some platforms we can't talk to bus dma address from the CPU, so for
			 * memory of type DRM_AGP, we'll deal with sorting out the real physical
			 * pages and mappings in nopage()
			 */
#if defined(__powerpc__)
			pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
#endif
			vma->vm_ops = &drm_vm_ops;
			break;
		}
		/* fall through to _DRM_FRAME_BUFFER... */
	case _DRM_FRAME_BUFFER:
	case _DRM_REGISTERS:
		offset = dev->driver->get_reg_ofs(dev);
		vma->vm_flags |= VM_IO;	/* not in core dump */
		vma->vm_page_prot = drm_io_prot(map->type, vma);
#ifdef __sparc__
		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
#endif
		if (io_remap_pfn_range(vma, vma->vm_start,
				       (map->offset + offset) >> PAGE_SHIFT,
				       vma->vm_end - vma->vm_start,
				       vma->vm_page_prot))
			return -EAGAIN;
		DRM_DEBUG("   Type = %d; start = 0x%lx, end = 0x%lx,"
			  " offset = 0x%lx\n",
			  map->type,
			  vma->vm_start, vma->vm_end, map->offset + offset);
		vma->vm_ops = &drm_vm_ops;
		break;
	case _DRM_CONSISTENT:
		/* Consistent memory is really like shared memory. But
		 * it's allocated in a different way, so avoid nopage */
		if (remap_pfn_range(vma, vma->vm_start,
		    page_to_pfn(virt_to_page(map->handle)),
		    vma->vm_end - vma->vm_start, vma->vm_page_prot))
			return -EAGAIN;
	/* fall through to _DRM_SHM */
	case _DRM_SHM:
		vma->vm_ops = &drm_vm_shm_ops;
		vma->vm_private_data = (void *)map;
		/* Don't let this area swap.  Change when
		   DRM_KERNEL advisory is supported. */
		vma->vm_flags |= VM_RESERVED;
		break;
	case _DRM_SCATTER_GATHER:
		vma->vm_ops = &drm_vm_sg_ops;
		vma->vm_private_data = (void *)map;
		vma->vm_flags |= VM_RESERVED;
		break;
	default:
		return -EINVAL;	/* This should never happen. */
	}
	vma->vm_flags |= VM_RESERVED;	/* Don't swap */
	vma->vm_flags |= VM_DONTEXPAND;

	vma->vm_file = filp;	/* Needed for drm_vm_open() */
	drm_vm_open_locked(vma);
	return 0;
}

int drm_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->head->dev;
	int ret;

	mutex_lock(&dev->struct_mutex);
	ret = drm_mmap_locked(filp, vma);
	mutex_unlock(&dev->struct_mutex);

	return ret;
}
EXPORT_SYMBOL(drm_mmap);