ion_cma_secure_heap.c

/*
 * drivers/staging/android/ion/ion_cma_secure_heap.c
 *
 * Copyright (C) Linaro 2012
 * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
 * Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/device.h>
#include <linux/ion.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/msm_ion.h>
#include <trace/events/kmem.h>

#include <soc/qcom/secure_buffer.h>
#include <asm/cacheflush.h>

/* for ion_heap_ops structure */
#include "ion.h"

#define ION_CMA_ALLOCATE_FAILED NULL

struct ion_secure_cma_non_contig_info {
	dma_addr_t phys;
	int len;
	struct list_head entry;
};

struct ion_secure_cma_buffer_info {
	dma_addr_t phys;
	struct sg_table *table;
	bool is_cached;
	int len;
	struct list_head non_contig_list;
	unsigned long ncelems;
};

struct ion_cma_alloc_chunk {
	void *cpu_addr;
	struct list_head entry;
	dma_addr_t handle;
	unsigned long chunk_size;
	atomic_t cnt;
};

struct ion_cma_secure_heap {
	struct device *dev;
	/*
	 * Protects against races between threads allocating memory/adding to
	 * pool at the same time. (e.g. thread 1 adds to pool, thread 2
	 * allocates thread 1's memory before thread 1 knows it needs to
	 * allocate more.
	 * Admittedly this is fairly coarse grained right now but the chance for
	 * contention on this lock is unlikely right now. This can be changed if
	 * this ever changes in the future
	 */
	struct mutex alloc_lock;
	/*
	 * protects the list of memory chunks in this pool
	 */
	struct mutex chunk_lock;
	struct ion_heap heap;
	/*
	 * Bitmap for allocation. This contains the aggregate of all chunks.
	 */
	unsigned long *bitmap;
	/*
	 * List of all allocated chunks
	 *
	 * This is where things get 'clever'. Individual allocations from
	 * dma_alloc_coherent must be allocated and freed in one chunk.
	 * We don't just want to limit the allocations to those confined
	 * within a single chunk (if clients allocate n small chunks we would
	 * never be able to use the combined size). The bitmap allocator is
	 * used to find the contiguous region and the parts of the chunks are
	 * marked off as used. The chunks won't be freed in the shrinker until
	 * the usage is actually zero.
	 */
	struct list_head chunks;
	int npages;
	phys_addr_t base;
	struct work_struct work;
	unsigned long last_alloc;
	struct shrinker shrinker;
	atomic_t total_allocated;
	atomic_t total_pool_size;
	atomic_t total_leaked;
	unsigned long heap_size;
	unsigned long default_prefetch_size;
};

static void ion_secure_pool_pages(struct work_struct *work);

static int ion_heap_allow_secure_allocation(enum ion_heap_type type)
{
	return type == ((enum ion_heap_type)ION_HEAP_TYPE_SECURE_DMA);
}

/*
 * Create scatter-list for the already allocated DMA buffer.
 * This function could be replace by dma_common_get_sgtable
 * as soon as it will avalaible.
 */
static int ion_secure_cma_get_sgtable(struct device *dev, struct sg_table *sgt,
				      dma_addr_t handle, size_t size)
{
	struct page *page = pfn_to_page(PFN_DOWN(handle));
	int ret;

	ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
	if (unlikely(ret))
		return ret;

	sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
	sg_dma_address(sgt->sgl) = handle;
	return 0;
}

static int ion_secure_cma_add_to_pool(
					struct ion_cma_secure_heap *sheap,
					unsigned long len,
					bool prefetch)
{
	void *cpu_addr;
	dma_addr_t handle;
	unsigned long attrs = 0;
	int ret = 0;
	struct ion_cma_alloc_chunk *chunk;

	trace_ion_secure_cma_add_to_pool_start(len,
					atomic_read(&sheap->total_pool_size),
					prefetch);
	mutex_lock(&sheap->chunk_lock);

	chunk = kzalloc(sizeof(*chunk), GFP_KERNEL);
	if (!chunk) {
		ret = -ENOMEM;
		goto out;
	}

	attrs = DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_SKIP_ZEROING;

	cpu_addr = dma_alloc_attrs(sheap->dev, len, &handle, GFP_KERNEL,
				   attrs);

	if (!cpu_addr) {
		ret = -ENOMEM;
		goto out_free;
	}

	chunk->cpu_addr = cpu_addr;
	chunk->handle = handle;
	chunk->chunk_size = len;
	atomic_set(&chunk->cnt, 0);
	list_add(&chunk->entry, &sheap->chunks);
	atomic_add(len, &sheap->total_pool_size);
	 /* clear the bitmap to indicate this region can be allocated from */
	bitmap_clear(sheap->bitmap, (handle - sheap->base) >> PAGE_SHIFT,
		     len >> PAGE_SHIFT);
	goto out;

out_free:
	kfree(chunk);
out:
	mutex_unlock(&sheap->chunk_lock);

	trace_ion_secure_cma_add_to_pool_end(len,
					atomic_read(&sheap->total_pool_size),
					prefetch);

	return ret;
}

static void ion_secure_pool_pages(struct work_struct *work)
{
	struct ion_cma_secure_heap *sheap = container_of(work,
			struct ion_cma_secure_heap, work);

	ion_secure_cma_add_to_pool(sheap, sheap->last_alloc, true);
}

/*
 * @s1: start of the first region
 * @l1: length of the first region
 * @s2: start of the second region
 * @l2: length of the second region
 *
 * Returns the total number of bytes that intersect.
 *
 * s1 is the region we are trying to clear so s2 may be subsumed by s1 but the
 * maximum size to clear should only ever be l1
 *
 */
static unsigned int intersect(unsigned long s1, unsigned long l1,
			      unsigned long s2, unsigned long l2)
{
	unsigned long base1 = s1;
	unsigned long end1 = s1 + l1;
	unsigned long base2 = s2;
	unsigned long end2 = s2 + l2;

	/* Case 0: The regions don't overlap at all */
	if (!(base1 < end2 && base2 < end1))
		return 0;

	/* Case 1: region 2 is subsumed by region 1 */
	if (base1 <= base2 && end2 <= end1)
		return l2;

	/* case 2: region 1 is subsumed by region 2 */
	if (base2 <= base1 && end1 <= end2)
		return l1;

	/* case 3: region1 overlaps region2 on the bottom */
	if (base2 < end1 && base2 > base1)
		return end1 - base2;

	/* case 4: region 2 overlaps region1 on the bottom */
	if (base1 < end2 && base1 > base2)
		return end2 - base1;

	pr_err("Bad math! Did not detect chunks correctly! %lx %lx %lx %lx\n",
	       s1, l1, s2, l2);
	WARN_ON(1);
	/* retrun max intersection value, so that it will fail later*/
	return (unsigned int)(~0);
}

int ion_secure_cma_prefetch(struct ion_heap *heap, void *data)
{
	unsigned long len = (unsigned long)data;
	struct ion_cma_secure_heap *sheap =
		container_of(heap, struct ion_cma_secure_heap, heap);
	unsigned long diff;

	if ((int)heap->type != ION_HEAP_TYPE_SECURE_DMA)
		return -EINVAL;

	if (len == 0)
		len = sheap->default_prefetch_size;

	/*
	 * Only prefetch as much space as there is left in the pool so
	 * check against the current free size of the heap.
	 * This is slightly racy if someone else is allocating at the same
	 * time. CMA has a restricted size for the heap so worst case
	 * the prefetch doesn't work because the allocation fails.
	 */
	diff = sheap->heap_size - atomic_read(&sheap->total_pool_size);

	if (len > diff)
		len = diff;

	sheap->last_alloc = len;
	trace_ion_prefetching(sheap->last_alloc);
	schedule_work(&sheap->work);

	return 0;
}

static void bad_math_dump(unsigned long len, int total_overlap,
			  struct ion_cma_secure_heap *sheap,
			  bool alloc, dma_addr_t paddr)
{
	struct list_head *entry;

	pr_err("Bad math! expected total was %lx actual was %x\n",
	       len, total_overlap);
	pr_err("attempted %s address was %pa len %lx\n",
	       alloc ? "allocation" : "free", &paddr, len);
	pr_err("chunks:\n");
	list_for_each(entry, &sheap->chunks) {
		struct ion_cma_alloc_chunk *chunk =
			container_of(entry,
				     struct ion_cma_alloc_chunk, entry);
		pr_info("---   pa %pa len %lx\n",
			&chunk->handle, chunk->chunk_size);
	}
	WARN(1, "mismatch in the sizes of secure cma chunks\n");
}

static int ion_secure_cma_alloc_from_pool(
					struct ion_cma_secure_heap *sheap,
					dma_addr_t *phys,
					unsigned long len)
{
	dma_addr_t paddr;
	unsigned long page_no;
	int ret = 0;
	int total_overlap = 0;
	struct list_head *entry;

	mutex_lock(&sheap->chunk_lock);

	page_no = bitmap_find_next_zero_area(sheap->bitmap,
					     sheap->npages, 0,
					     len >> PAGE_SHIFT, 0);
	if (page_no >= sheap->npages) {
		ret = -ENOMEM;
		goto out;
	}
	bitmap_set(sheap->bitmap, page_no, len >> PAGE_SHIFT);
	paddr = sheap->base + (page_no << PAGE_SHIFT);

	list_for_each(entry, &sheap->chunks) {
		struct ion_cma_alloc_chunk *chunk = container_of(entry,
					struct ion_cma_alloc_chunk, entry);
		int overlap = intersect(chunk->handle,
					chunk->chunk_size, paddr, len);

		atomic_add(overlap, &chunk->cnt);
		total_overlap += overlap;
	}

	if (total_overlap != len) {
		bad_math_dump(len, total_overlap, sheap, 1, paddr);
		ret = -EINVAL;
		goto out;
	}

	*phys = paddr;
out:
	mutex_unlock(&sheap->chunk_lock);
	return ret;
}

static void ion_secure_cma_free_chunk(struct ion_cma_secure_heap *sheap,
				      struct ion_cma_alloc_chunk *chunk)
{
	unsigned long attrs = 0;

	attrs = DMA_ATTR_NO_KERNEL_MAPPING;
	/* This region is 'allocated' and not available to allocate from */
	bitmap_set(sheap->bitmap, (chunk->handle - sheap->base) >> PAGE_SHIFT,
		   chunk->chunk_size >> PAGE_SHIFT);
	dma_free_attrs(sheap->dev, chunk->chunk_size, chunk->cpu_addr,
		       chunk->handle, attrs);
	atomic_sub(chunk->chunk_size, &sheap->total_pool_size);
	list_del(&chunk->entry);
	kfree(chunk);
}

static unsigned long
__ion_secure_cma_shrink_pool(struct ion_cma_secure_heap *sheap, int max_nr)
{
	struct list_head *entry, *_n;
	unsigned long drained_size = 0, skipped_size = 0;

	trace_ion_secure_cma_shrink_pool_start(drained_size, skipped_size);

	list_for_each_safe(entry, _n, &sheap->chunks) {
		struct ion_cma_alloc_chunk *chunk = container_of(entry,
					struct ion_cma_alloc_chunk, entry);

		if (max_nr < 0)
			break;

		if (atomic_read(&chunk->cnt) == 0) {
			max_nr -= chunk->chunk_size;
			drained_size += chunk->chunk_size;
			ion_secure_cma_free_chunk(sheap, chunk);
		} else {
			skipped_size += chunk->chunk_size;
		}
	}

	trace_ion_secure_cma_shrink_pool_end(drained_size, skipped_size);
	return drained_size;
}

int ion_secure_cma_drain_pool(struct ion_heap *heap, void *unused)
{
	struct ion_cma_secure_heap *sheap =
		container_of(heap, struct ion_cma_secure_heap, heap);

	mutex_lock(&sheap->chunk_lock);
	__ion_secure_cma_shrink_pool(sheap, INT_MAX);
	mutex_unlock(&sheap->chunk_lock);

	return 0;
}

static unsigned long ion_secure_cma_shrinker(struct shrinker *shrinker,
					     struct shrink_control *sc)
{
	unsigned long freed;
	struct ion_cma_secure_heap *sheap = container_of(shrinker,
					struct ion_cma_secure_heap, shrinker);
	int nr_to_scan = sc->nr_to_scan;

	/*
	 * Allocation path may invoke the shrinker. Proceeding any further
	 * would cause a deadlock in several places so don't shrink if that
	 * happens.
	 */
	if (!mutex_trylock(&sheap->chunk_lock))
		return -EAGAIN;

	freed = __ion_secure_cma_shrink_pool(sheap, nr_to_scan);

	mutex_unlock(&sheap->chunk_lock);

	return freed;
}

static unsigned long ion_secure_cma_shrinker_count(struct shrinker *shrinker,
						   struct shrink_control *sc)
{
	struct ion_cma_secure_heap *sheap = container_of(shrinker,
					struct ion_cma_secure_heap, shrinker);
	return atomic_read(&sheap->total_pool_size);
}

static void ion_secure_cma_free_from_pool(struct ion_cma_secure_heap *sheap,
					  dma_addr_t handle,
					  unsigned long len)
{
	struct list_head *entry, *_n;
	int total_overlap = 0;

	mutex_lock(&sheap->chunk_lock);
	bitmap_clear(sheap->bitmap, (handle - sheap->base) >> PAGE_SHIFT,
		     len >> PAGE_SHIFT);

	list_for_each_safe(entry, _n, &sheap->chunks) {
		struct ion_cma_alloc_chunk *chunk = container_of(entry,
					struct ion_cma_alloc_chunk, entry);
		int overlap = intersect(chunk->handle,
					chunk->chunk_size, handle, len);

		/*
		 * Don't actually free this from the pool list yet, let either
		 * an explicit drain call or the shrinkers take care of the
		 * pool.
		 */
		atomic_sub_return(overlap, &chunk->cnt);
		if (atomic_read(&chunk->cnt) < 0) {
			WARN(1, "Invalid chunk size of %d\n",
			     atomic_read(&chunk->cnt));
			goto out;
		}

		total_overlap += overlap;
	}

	if (atomic_read(&sheap->total_pool_size) < 0) {
		WARN(1, "total pool size of %d is unexpected\n",
		     atomic_read(&sheap->total_pool_size));
		goto out;
	}

	if (total_overlap != len)
		bad_math_dump(len, total_overlap, sheap, 0, handle);
out:
	mutex_unlock(&sheap->chunk_lock);
}

/* ION CMA heap operations functions */
static struct ion_secure_cma_buffer_info *__ion_secure_cma_allocate(
			    struct ion_heap *heap, struct ion_buffer *buffer,
			    unsigned long len,
			    unsigned long flags)
{
	struct ion_cma_secure_heap *sheap =
		container_of(heap, struct ion_cma_secure_heap, heap);
	struct ion_secure_cma_buffer_info *info;
	int ret;

	dev_dbg(sheap->dev, "Request buffer allocation len %ld\n", len);

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return ION_CMA_ALLOCATE_FAILED;

	mutex_lock(&sheap->alloc_lock);
	ret = ion_secure_cma_alloc_from_pool(sheap, &info->phys, len);

	if (ret) {
retry:
		ret = ion_secure_cma_add_to_pool(sheap, len, false);
		if (ret) {
			mutex_unlock(&sheap->alloc_lock);
			dev_err(sheap->dev, "Fail to allocate buffer\n");
			goto err;
		}
		ret = ion_secure_cma_alloc_from_pool(sheap, &info->phys, len);
		if (ret) {
			/*
			 * Lost the race with the shrinker, try again
			 */
			goto retry;
		}
	}
	mutex_unlock(&sheap->alloc_lock);

	atomic_add(len, &sheap->total_allocated);
	info->table = kmalloc(sizeof(*info->table), GFP_KERNEL);
	if (!info->table) {
		dev_err(sheap->dev, "Fail to allocate sg table\n");
		goto err;
	}

	info->len = len;
	ion_secure_cma_get_sgtable(sheap->dev,
				   info->table, info->phys, len);

	/* keep this for memory release */
	buffer->priv_virt = info;
	dev_dbg(sheap->dev, "Allocate buffer %pK\n", buffer);
	return info;

err:
	kfree(info);
	return ION_CMA_ALLOCATE_FAILED;
}

static void __ion_secure_cma_free_non_contig(struct ion_cma_secure_heap *sheap,
					     struct ion_secure_cma_buffer_info
					     *info)
{
	struct ion_secure_cma_non_contig_info *nc_info, *temp;

	list_for_each_entry_safe(nc_info, temp, &info->non_contig_list, entry) {
		ion_secure_cma_free_from_pool(sheap, nc_info->phys,
					      nc_info->len);
		list_del(&nc_info->entry);
		kfree(nc_info);
	}
}

static void __ion_secure_cma_free(struct ion_cma_secure_heap *sheap,
				  struct ion_secure_cma_buffer_info *info,
				  bool release_memory)
{
	if (release_memory) {
		if (info->ncelems)
			__ion_secure_cma_free_non_contig(sheap, info);
		else
			ion_secure_cma_free_from_pool(sheap, info->phys,
						      info->len);
	}
	sg_free_table(info->table);
	kfree(info->table);
	kfree(info);
}

static struct ion_secure_cma_buffer_info *__ion_secure_cma_allocate_non_contig(
			struct ion_heap *heap, struct ion_buffer *buffer,
			unsigned long len,
			unsigned long flags)
{
	struct ion_cma_secure_heap *sheap =
		container_of(heap, struct ion_cma_secure_heap, heap);
	struct ion_secure_cma_buffer_info *info;
	int ret;
	unsigned long alloc_size = len;
	struct ion_secure_cma_non_contig_info *nc_info, *temp;
	unsigned long ncelems = 0;
	struct scatterlist *sg;
	unsigned long total_allocated = 0;

	dev_dbg(sheap->dev, "Request buffer allocation len %ld\n", len);

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return ION_CMA_ALLOCATE_FAILED;

	INIT_LIST_HEAD(&info->non_contig_list);
	info->table = kmalloc(sizeof(*info->table), GFP_KERNEL);
	if (!info->table) {
		dev_err(sheap->dev, "Fail to allocate sg table\n");
		goto err;
	}
	mutex_lock(&sheap->alloc_lock);
	while (total_allocated < len) {
		if (alloc_size < SZ_1M) {
			pr_err("Cannot allocate less than 1MB\n");
			goto err2;
		}
		nc_info = kzalloc(sizeof(*nc_info), GFP_KERNEL);
		if (!nc_info)
			goto err2;

		ret = ion_secure_cma_alloc_from_pool(sheap, &nc_info->phys,
						     alloc_size);
		if (ret) {
retry:
			ret = ion_secure_cma_add_to_pool(sheap, alloc_size,
							 false);
			if (ret) {
				alloc_size = alloc_size / 2;
				if (!IS_ALIGNED(alloc_size, SZ_1M))
					alloc_size = round_down(alloc_size,
								SZ_1M);
				kfree(nc_info);
				continue;
			}
			ret = ion_secure_cma_alloc_from_pool(sheap,
							     &nc_info->phys,
							     alloc_size);
			if (ret) {
				/*
				 * Lost the race with the shrinker, try again
				 */
				goto retry;
			}
		}
		nc_info->len = alloc_size;
		list_add_tail(&nc_info->entry, &info->non_contig_list);
		ncelems++;
		total_allocated += alloc_size;
		alloc_size = min(alloc_size, len - total_allocated);
	}
	mutex_unlock(&sheap->alloc_lock);
	atomic_add(total_allocated, &sheap->total_allocated);

	nc_info = list_first_entry_or_null(&info->non_contig_list,
					   struct
					   ion_secure_cma_non_contig_info,
					   entry);
	if (!nc_info) {
		pr_err("%s: Unable to find first entry of non contig list\n",
		       __func__);
		goto err1;
	}
	info->phys = nc_info->phys;
	info->len = total_allocated;
	info->ncelems = ncelems;

	ret = sg_alloc_table(info->table, ncelems, GFP_KERNEL);
	if (unlikely(ret))
		goto err1;

	sg = info->table->sgl;
	list_for_each_entry(nc_info, &info->non_contig_list, entry) {
		sg_set_page(sg, phys_to_page(nc_info->phys), nc_info->len, 0);
		sg_dma_address(sg) = nc_info->phys;
		sg = sg_next(sg);
	}
	buffer->priv_virt = info;
	dev_dbg(sheap->dev, "Allocate buffer %pK\n", buffer);
	return info;

err2:
	mutex_unlock(&sheap->alloc_lock);
err1:
	list_for_each_entry_safe(nc_info, temp, &info->non_contig_list,
				 entry) {
		list_del(&nc_info->entry);
		kfree(nc_info);
	}
	kfree(info->table);
err:
	kfree(info);
	return ION_CMA_ALLOCATE_FAILED;
}

static int ion_secure_cma_allocate(struct ion_heap *heap,
				   struct ion_buffer *buffer,
				   unsigned long len,
				   unsigned long flags)
{
	unsigned long secure_allocation = flags & ION_FLAG_SECURE;
	struct ion_secure_cma_buffer_info *buf = NULL;
	unsigned long allow_non_contig = flags & ION_FLAG_ALLOW_NON_CONTIG;

	if (!secure_allocation &&
	    !ion_heap_allow_secure_allocation(heap->type)) {
		pr_err("%s: non-secure allocation disallowed from heap %s %lx\n",
		       __func__, heap->name, flags);
		return -ENOMEM;
	}

	if (ION_IS_CACHED(flags)) {
		pr_err("%s: cannot allocate cached memory from secure heap %s\n",
		       __func__, heap->name);
		return -ENOMEM;
	}

	if (!IS_ALIGNED(len, SZ_1M)) {
		pr_err("%s: length of allocation from %s must be a multiple of 1MB\n",
		       __func__, heap->name);
		return -ENOMEM;
	}
	trace_ion_secure_cma_allocate_start(heap->name, len, flags);
	if (!allow_non_contig)
		buf = __ion_secure_cma_allocate(heap, buffer, len,
						flags);
	else
		buf = __ion_secure_cma_allocate_non_contig(heap, buffer, len,
							   flags);
	trace_ion_secure_cma_allocate_end(heap->name, len, flags);
	if (buf) {
		int ret;

		if (!msm_secure_v2_is_supported()) {
			pr_err("%s: securing buffers from clients is not supported on this platform\n",
			       __func__);
			ret = 1;
		} else {
			trace_ion_cp_secure_buffer_start(heap->name, len,
							 flags);
			ret = msm_secure_table(buf->table);
			trace_ion_cp_secure_buffer_end(heap->name, len,
						       flags);
		}
		if (ret) {
			struct ion_cma_secure_heap *sheap =
				container_of(buffer->heap,
					     struct ion_cma_secure_heap, heap);

			pr_err("%s: failed to secure buffer\n", __func__);
			__ion_secure_cma_free(sheap, buf, true);
		}
		return ret;
	} else {
		return -ENOMEM;
	}
}

static void ion_secure_cma_free(struct ion_buffer *buffer)
{
	struct ion_cma_secure_heap *sheap =
		container_of(buffer->heap, struct ion_cma_secure_heap, heap);
	struct ion_secure_cma_buffer_info *info = buffer->priv_virt;
	int ret = 0;

	dev_dbg(sheap->dev, "Release buffer %pK\n", buffer);
	if (msm_secure_v2_is_supported())
		ret = msm_unsecure_table(info->table);
	atomic_sub(buffer->size, &sheap->total_allocated);
	if (atomic_read(&sheap->total_allocated) < 0) {
		WARN(1, "no memory is allocated from this pool\n");
		return;
	}

	/* release memory */
	if (ret) {
		WARN(1, "Unsecure failed, can't free the memory. Leaking it!");
		atomic_add(buffer->size, &sheap->total_leaked);
	}

	__ion_secure_cma_free(sheap, info, ret ? false : true);
}

static int ion_secure_cma_mmap(struct ion_heap *mapper,
			       struct ion_buffer *buffer,
			       struct vm_area_struct *vma)
{
	pr_info("%s: mmaping from secure heap %s disallowed\n",
		__func__, mapper->name);
	return -EINVAL;
}

static void *ion_secure_cma_map_kernel(struct ion_heap *heap,
				       struct ion_buffer *buffer)
{
	pr_info("%s: kernel mapping from secure heap %s disallowed\n",
		__func__, heap->name);
	return ERR_PTR(-EINVAL);
}

static void ion_secure_cma_unmap_kernel(struct ion_heap *heap,
					struct ion_buffer *buffer)
{
}

static struct ion_heap_ops ion_secure_cma_ops = {
	.allocate = ion_secure_cma_allocate,
	.free = ion_secure_cma_free,
	.map_user = ion_secure_cma_mmap,
	.map_kernel = ion_secure_cma_map_kernel,
	.unmap_kernel = ion_secure_cma_unmap_kernel,
};

struct ion_heap *ion_secure_cma_heap_create(struct ion_platform_heap *data)
{
	struct ion_cma_secure_heap *sheap;
	int map_size = BITS_TO_LONGS(data->size >> PAGE_SHIFT) * sizeof(long);

	sheap = kzalloc(sizeof(*sheap), GFP_KERNEL);
	if (!sheap)
		return ERR_PTR(-ENOMEM);

	sheap->dev = data->priv;
	mutex_init(&sheap->chunk_lock);
	mutex_init(&sheap->alloc_lock);
	sheap->heap.ops = &ion_secure_cma_ops;
	sheap->heap.type = (enum ion_heap_type)ION_HEAP_TYPE_SECURE_DMA;
	sheap->npages = data->size >> PAGE_SHIFT;
	sheap->base = data->base;
	sheap->heap_size = data->size;
	sheap->bitmap = kmalloc(map_size, GFP_KERNEL);
	INIT_LIST_HEAD(&sheap->chunks);
	INIT_WORK(&sheap->work, ion_secure_pool_pages);
	sheap->shrinker.seeks = DEFAULT_SEEKS;
	sheap->shrinker.batch = 0;
	sheap->shrinker.scan_objects = ion_secure_cma_shrinker;
	sheap->shrinker.count_objects = ion_secure_cma_shrinker_count;
	sheap->default_prefetch_size = sheap->heap_size;
	register_shrinker(&sheap->shrinker);

	if (!sheap->bitmap) {
		kfree(sheap);
		return ERR_PTR(-ENOMEM);
	}

	/*
	 * we initially mark everything in the allocator as being free so that
	 * allocations can come in later
	 */
	bitmap_fill(sheap->bitmap, sheap->npages);

	return &sheap->heap;
}

void ion_secure_cma_heap_destroy(struct ion_heap *heap)
{
	struct ion_cma_secure_heap *sheap =
		container_of(heap, struct ion_cma_secure_heap, heap);

	kfree(sheap);
}