[linux.git] / drivers / tee / tee_shm.c

/*
 * Copyright (c) 2015-2016, Linaro Limited
 *
 * 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/dma-buf.h>
#include <linux/fdtable.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/tee_drv.h>
#include "tee_private.h"

static void tee_shm_release(struct tee_shm *shm)
{
	struct tee_device *teedev = shm->teedev;
	struct tee_shm_pool_mgr *poolm;

	mutex_lock(&teedev->mutex);
	idr_remove(&teedev->idr, shm->id);
	if (shm->ctx)
		list_del(&shm->link);
	mutex_unlock(&teedev->mutex);

	if (shm->flags & TEE_SHM_DMA_BUF)
		poolm = &teedev->pool->dma_buf_mgr;
	else
		poolm = &teedev->pool->private_mgr;

	poolm->ops->free(poolm, shm);
	kfree(shm);

	tee_device_put(teedev);
}

static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
			*attach, enum dma_data_direction dir)
{
	return NULL;
}

static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
				     struct sg_table *table,
				     enum dma_data_direction dir)
{
}

static void tee_shm_op_release(struct dma_buf *dmabuf)
{
	struct tee_shm *shm = dmabuf->priv;

	tee_shm_release(shm);
}

static void *tee_shm_op_map_atomic(struct dma_buf *dmabuf, unsigned long pgnum)
{
	return NULL;
}

static void *tee_shm_op_map(struct dma_buf *dmabuf, unsigned long pgnum)
{
	return NULL;
}

static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
{
	struct tee_shm *shm = dmabuf->priv;
	size_t size = vma->vm_end - vma->vm_start;

	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
			       size, vma->vm_page_prot);
}

static const struct dma_buf_ops tee_shm_dma_buf_ops = {
	.map_dma_buf = tee_shm_op_map_dma_buf,
	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
	.release = tee_shm_op_release,
	.map_atomic = tee_shm_op_map_atomic,
	.map = tee_shm_op_map,
	.mmap = tee_shm_op_mmap,
};

/**
 * tee_shm_alloc() - Allocate shared memory
 * @ctx:	Context that allocates the shared memory
 * @size:	Requested size of shared memory
 * @flags:	Flags setting properties for the requested shared memory.
 *
 * Memory allocated as global shared memory is automatically freed when the
 * TEE file pointer is closed. The @flags field uses the bits defined by
 * TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
 * set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
 * associated with a dma-buf handle, else driver private memory.
 */
struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags)
{
	struct tee_device *teedev = ctx->teedev;
	struct tee_shm_pool_mgr *poolm = NULL;
	struct tee_shm *shm;
	void *ret;
	int rc;

	if (!(flags & TEE_SHM_MAPPED)) {
		dev_err(teedev->dev.parent,
			"only mapped allocations supported\n");
		return ERR_PTR(-EINVAL);
	}

	if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) {
		dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
		return ERR_PTR(-EINVAL);
	}

	if (!tee_device_get(teedev))
		return ERR_PTR(-EINVAL);

	if (!teedev->pool) {
		/* teedev has been detached from driver */
		ret = ERR_PTR(-EINVAL);
		goto err_dev_put;
	}

	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
	if (!shm) {
		ret = ERR_PTR(-ENOMEM);
		goto err_dev_put;
	}

	shm->flags = flags;
	shm->teedev = teedev;
	shm->ctx = ctx;
	if (flags & TEE_SHM_DMA_BUF)
		poolm = &teedev->pool->dma_buf_mgr;
	else
		poolm = &teedev->pool->private_mgr;

	rc = poolm->ops->alloc(poolm, shm, size);
	if (rc) {
		ret = ERR_PTR(rc);
		goto err_kfree;
	}

	mutex_lock(&teedev->mutex);
	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
	mutex_unlock(&teedev->mutex);
	if (shm->id < 0) {
		ret = ERR_PTR(shm->id);
		goto err_pool_free;
	}

	if (flags & TEE_SHM_DMA_BUF) {
		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

		exp_info.ops = &tee_shm_dma_buf_ops;
		exp_info.size = shm->size;
		exp_info.flags = O_RDWR;
		exp_info.priv = shm;

		shm->dmabuf = dma_buf_export(&exp_info);
		if (IS_ERR(shm->dmabuf)) {
			ret = ERR_CAST(shm->dmabuf);
			goto err_rem;
		}
	}
	mutex_lock(&teedev->mutex);
	list_add_tail(&shm->link, &ctx->list_shm);
	mutex_unlock(&teedev->mutex);

	return shm;
err_rem:
	mutex_lock(&teedev->mutex);
	idr_remove(&teedev->idr, shm->id);
	mutex_unlock(&teedev->mutex);
err_pool_free:
	poolm->ops->free(poolm, shm);
err_kfree:
	kfree(shm);
err_dev_put:
	tee_device_put(teedev);
	return ret;
}
EXPORT_SYMBOL_GPL(tee_shm_alloc);

/**
 * tee_shm_get_fd() - Increase reference count and return file descriptor
 * @shm:	Shared memory handle
 * @returns user space file descriptor to shared memory
 */
int tee_shm_get_fd(struct tee_shm *shm)
{
	u32 req_flags = TEE_SHM_MAPPED | TEE_SHM_DMA_BUF;
	int fd;

	if ((shm->flags & req_flags) != req_flags)
		return -EINVAL;

	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
	if (fd >= 0)
		get_dma_buf(shm->dmabuf);
	return fd;
}

/**
 * tee_shm_free() - Free shared memory
 * @shm:	Handle to shared memory to free
 */
void tee_shm_free(struct tee_shm *shm)
{
	/*
	 * dma_buf_put() decreases the dmabuf reference counter and will
	 * call tee_shm_release() when the last reference is gone.
	 *
	 * In the case of driver private memory we call tee_shm_release
	 * directly instead as it doesn't have a reference counter.
	 */
	if (shm->flags & TEE_SHM_DMA_BUF)
		dma_buf_put(shm->dmabuf);
	else
		tee_shm_release(shm);
}
EXPORT_SYMBOL_GPL(tee_shm_free);

/**
 * tee_shm_va2pa() - Get physical address of a virtual address
 * @shm:	Shared memory handle
 * @va:		Virtual address to tranlsate
 * @pa:		Returned physical address
 * @returns 0 on success and < 0 on failure
 */
int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa)
{
	/* Check that we're in the range of the shm */
	if ((char *)va < (char *)shm->kaddr)
		return -EINVAL;
	if ((char *)va >= ((char *)shm->kaddr + shm->size))
		return -EINVAL;

	return tee_shm_get_pa(
			shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
}
EXPORT_SYMBOL_GPL(tee_shm_va2pa);

/**
 * tee_shm_pa2va() - Get virtual address of a physical address
 * @shm:	Shared memory handle
 * @pa:		Physical address to tranlsate
 * @va:		Returned virtual address
 * @returns 0 on success and < 0 on failure
 */
int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va)
{
	/* Check that we're in the range of the shm */
	if (pa < shm->paddr)
		return -EINVAL;
	if (pa >= (shm->paddr + shm->size))
		return -EINVAL;

	if (va) {
		void *v = tee_shm_get_va(shm, pa - shm->paddr);

		if (IS_ERR(v))
			return PTR_ERR(v);
		*va = v;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(tee_shm_pa2va);

/**
 * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
 * @shm:	Shared memory handle
 * @offs:	Offset from start of this shared memory
 * @returns virtual address of the shared memory + offs if offs is within
 *	the bounds of this shared memory, else an ERR_PTR
 */
void *tee_shm_get_va(struct tee_shm *shm, size_t offs)
{
	if (offs >= shm->size)
		return ERR_PTR(-EINVAL);
	return (char *)shm->kaddr + offs;
}
EXPORT_SYMBOL_GPL(tee_shm_get_va);

/**
 * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
 * @shm:	Shared memory handle
 * @offs:	Offset from start of this shared memory
 * @pa:		Physical address to return
 * @returns 0 if offs is within the bounds of this shared memory, else an
 *	error code.
 */
int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa)
{
	if (offs >= shm->size)
		return -EINVAL;
	if (pa)
		*pa = shm->paddr + offs;
	return 0;
}
EXPORT_SYMBOL_GPL(tee_shm_get_pa);

/**
 * tee_shm_get_from_id() - Find shared memory object and increase reference
 * count
 * @ctx:	Context owning the shared memory
 * @id:		Id of shared memory object
 * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
 */
struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id)
{
	struct tee_device *teedev;
	struct tee_shm *shm;

	if (!ctx)
		return ERR_PTR(-EINVAL);

	teedev = ctx->teedev;
	mutex_lock(&teedev->mutex);
	shm = idr_find(&teedev->idr, id);
	if (!shm || shm->ctx != ctx)
		shm = ERR_PTR(-EINVAL);
	else if (shm->flags & TEE_SHM_DMA_BUF)
		get_dma_buf(shm->dmabuf);
	mutex_unlock(&teedev->mutex);
	return shm;
}
EXPORT_SYMBOL_GPL(tee_shm_get_from_id);

/**
 * tee_shm_get_id() - Get id of a shared memory object
 * @shm:	Shared memory handle
 * @returns id
 */
int tee_shm_get_id(struct tee_shm *shm)
{
	return shm->id;
}
EXPORT_SYMBOL_GPL(tee_shm_get_id);

/**
 * tee_shm_put() - Decrease reference count on a shared memory handle
 * @shm:	Shared memory handle
 */
void tee_shm_put(struct tee_shm *shm)
{
	if (shm->flags & TEE_SHM_DMA_BUF)
		dma_buf_put(shm->dmabuf);
}
EXPORT_SYMBOL_GPL(tee_shm_put);
Commit	Line	Data
967c9cca JW	1	/*
	2	* Copyright (c) 2015-2016, Linaro Limited
	3	*
	4	* This software is licensed under the terms of the GNU General Public
	5	* License version 2, as published by the Free Software Foundation, and
	6	* may be copied, distributed, and modified under those terms.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*
	13	*/
	14	#include <linux/device.h>
	15	#include <linux/dma-buf.h>
	16	#include <linux/fdtable.h>
	17	#include <linux/idr.h>
	18	#include <linux/sched.h>
	19	#include <linux/slab.h>
	20	#include <linux/tee_drv.h>
	21	#include "tee_private.h"
	22
	23	static void tee_shm_release(struct tee_shm *shm)
	24	{
	25	struct tee_device *teedev = shm->teedev;
	26	struct tee_shm_pool_mgr *poolm;
	27
	28	mutex_lock(&teedev->mutex);
	29	idr_remove(&teedev->idr, shm->id);
	30	if (shm->ctx)
	31	list_del(&shm->link);
	32	mutex_unlock(&teedev->mutex);
	33
	34	if (shm->flags & TEE_SHM_DMA_BUF)
	35	poolm = &teedev->pool->dma_buf_mgr;
	36	else
	37	poolm = &teedev->pool->private_mgr;
	38
	39	poolm->ops->free(poolm, shm);
	40	kfree(shm);
	41
	42	tee_device_put(teedev);
	43	}
	44
	45	static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment
	46	*attach, enum dma_data_direction dir)
	47	{
	48	return NULL;
	49	}
	50
	51	static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach,
	52	struct sg_table *table,
	53	enum dma_data_direction dir)
	54	{
	55	}
	56
	57	static void tee_shm_op_release(struct dma_buf *dmabuf)
	58	{
	59	struct tee_shm *shm = dmabuf->priv;
	60
	61	tee_shm_release(shm);
	62	}
	63
a2d9214c	64	static void tee_shm_op_map_atomic(struct dma_buf dmabuf, unsigned long pgnum)
967c9cca JW	65	{
	66	return NULL;
	67	}
	68
a2d9214c	69	static void tee_shm_op_map(struct dma_buf dmabuf, unsigned long pgnum)
967c9cca JW	70	{
	71	return NULL;
	72	}
	73
	74	static int tee_shm_op_mmap(struct dma_buf dmabuf, struct vm_area_struct vma)
	75	{
	76	struct tee_shm *shm = dmabuf->priv;
	77	size_t size = vma->vm_end - vma->vm_start;
	78
	79	return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT,
	80	size, vma->vm_page_prot);
	81	}
	82
53e3ca5c	83	static const struct dma_buf_ops tee_shm_dma_buf_ops = {
967c9cca JW	84	.map_dma_buf = tee_shm_op_map_dma_buf,
	85	.unmap_dma_buf = tee_shm_op_unmap_dma_buf,
	86	.release = tee_shm_op_release,
a2d9214c LT	87	.map_atomic = tee_shm_op_map_atomic,
a2d9214c LT	88	.map = tee_shm_op_map,
967c9cca JW	89	.mmap = tee_shm_op_mmap,
	90	};
	91
	92	/**
	93	* tee_shm_alloc() - Allocate shared memory
	94	* @ctx: Context that allocates the shared memory
	95	* @size: Requested size of shared memory
	96	* @flags: Flags setting properties for the requested shared memory.
	97	*
	98	* Memory allocated as global shared memory is automatically freed when the
	99	* TEE file pointer is closed. The @flags field uses the bits defined by
	100	* TEE_SHM_* in <linux/tee_drv.h>. TEE_SHM_MAPPED must currently always be
	101	* set. If TEE_SHM_DMA_BUF global shared memory will be allocated and
	102	* associated with a dma-buf handle, else driver private memory.
	103	*/
	104	struct tee_shm tee_shm_alloc(struct tee_context ctx, size_t size, u32 flags)
	105	{
	106	struct tee_device *teedev = ctx->teedev;
	107	struct tee_shm_pool_mgr *poolm = NULL;
	108	struct tee_shm *shm;
	109	void *ret;
	110	int rc;
	111
	112	if (!(flags & TEE_SHM_MAPPED)) {
	113	dev_err(teedev->dev.parent,
	114	"only mapped allocations supported\n");
	115	return ERR_PTR(-EINVAL);
	116	}
	117
	118	if ((flags & ~(TEE_SHM_MAPPED \| TEE_SHM_DMA_BUF))) {
	119	dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags);
	120	return ERR_PTR(-EINVAL);
	121	}
	122
	123	if (!tee_device_get(teedev))
	124	return ERR_PTR(-EINVAL);
	125
	126	if (!teedev->pool) {
	127	/* teedev has been detached from driver */
	128	ret = ERR_PTR(-EINVAL);
	129	goto err_dev_put;
	130	}
	131
	132	shm = kzalloc(sizeof(*shm), GFP_KERNEL);
	133	if (!shm) {
	134	ret = ERR_PTR(-ENOMEM);
	135	goto err_dev_put;
	136	}
	137
	138	shm->flags = flags;
	139	shm->teedev = teedev;
	140	shm->ctx = ctx;
	141	if (flags & TEE_SHM_DMA_BUF)
	142	poolm = &teedev->pool->dma_buf_mgr;
	143	else
	144	poolm = &teedev->pool->private_mgr;
	145
	146	rc = poolm->ops->alloc(poolm, shm, size);
	147	if (rc) {
	148	ret = ERR_PTR(rc);
	149	goto err_kfree;
	150	}
	151
	152	mutex_lock(&teedev->mutex);
153	shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
154	mutex_unlock(&teedev->mutex);
155	if (shm->id < 0) {
156	ret = ERR_PTR(shm->id);
157	goto err_pool_free;
158	}
159
160	if (flags & TEE_SHM_DMA_BUF) {
161	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
162
163	exp_info.ops = &tee_shm_dma_buf_ops;
164	exp_info.size = shm->size;
165	exp_info.flags = O_RDWR;
166	exp_info.priv = shm;
167
168	shm->dmabuf = dma_buf_export(&exp_info);
169	if (IS_ERR(shm->dmabuf)) {
170	ret = ERR_CAST(shm->dmabuf);
171	goto err_rem;
172	}
173	}
174	mutex_lock(&teedev->mutex);
175	list_add_tail(&shm->link, &ctx->list_shm);
176	mutex_unlock(&teedev->mutex);
177
178	return shm;
179	err_rem:
180	mutex_lock(&teedev->mutex);
181	idr_remove(&teedev->idr, shm->id);
182	mutex_unlock(&teedev->mutex);
183	err_pool_free:
184	poolm->ops->free(poolm, shm);
185	err_kfree:
186	kfree(shm);
187	err_dev_put:
188	tee_device_put(teedev);
189	return ret;
190	}
191	EXPORT_SYMBOL_GPL(tee_shm_alloc);
192
193	/**
194	* tee_shm_get_fd() - Increase reference count and return file descriptor
195	* @shm: Shared memory handle
196	* @returns user space file descriptor to shared memory
197	*/
198	int tee_shm_get_fd(struct tee_shm *shm)
199	{
200	u32 req_flags = TEE_SHM_MAPPED \| TEE_SHM_DMA_BUF;
201	int fd;
202
203	if ((shm->flags & req_flags) != req_flags)
204	return -EINVAL;
205
206	fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC);
207	if (fd >= 0)
208	get_dma_buf(shm->dmabuf);
209	return fd;
210	}
211
212	/**
213	* tee_shm_free() - Free shared memory
214	* @shm: Handle to shared memory to free
215	*/
216	void tee_shm_free(struct tee_shm *shm)
217	{
218	/*
219	* dma_buf_put() decreases the dmabuf reference counter and will
220	* call tee_shm_release() when the last reference is gone.
221	*
222	* In the case of driver private memory we call tee_shm_release
223	* directly instead as it doesn't have a reference counter.
224	*/
225	if (shm->flags & TEE_SHM_DMA_BUF)
226	dma_buf_put(shm->dmabuf);
227	else
228	tee_shm_release(shm);
229	}
230	EXPORT_SYMBOL_GPL(tee_shm_free);
231
232	/**
233	* tee_shm_va2pa() - Get physical address of a virtual address
234	* @shm: Shared memory handle
235	* @va: Virtual address to tranlsate
236	* @pa: Returned physical address
237	* @returns 0 on success and < 0 on failure
238	*/
239	int tee_shm_va2pa(struct tee_shm shm, void va, phys_addr_t *pa)
240	{
241	/* Check that we're in the range of the shm */
242	if ((char )va < (char )shm->kaddr)
243	return -EINVAL;
244	if ((char )va >= ((char )shm->kaddr + shm->size))
245	return -EINVAL;
246
247	return tee_shm_get_pa(
248	shm, (unsigned long)va - (unsigned long)shm->kaddr, pa);
249	}
250	EXPORT_SYMBOL_GPL(tee_shm_va2pa);
251
252	/**
253	* tee_shm_pa2va() - Get virtual address of a physical address
254	* @shm: Shared memory handle
255	* @pa: Physical address to tranlsate
256	* @va: Returned virtual address
257	* @returns 0 on success and < 0 on failure
258	*/
259	int tee_shm_pa2va(struct tee_shm shm, phys_addr_t pa, void *va)
260	{
261	/* Check that we're in the range of the shm */
262	if (pa < shm->paddr)
263	return -EINVAL;
264	if (pa >= (shm->paddr + shm->size))
265	return -EINVAL;
266
267	if (va) {
268	void *v = tee_shm_get_va(shm, pa - shm->paddr);
269
270	if (IS_ERR(v))
271	return PTR_ERR(v);
272	*va = v;
273	}
274	return 0;
275	}
276	EXPORT_SYMBOL_GPL(tee_shm_pa2va);
277
278	/**
279	* tee_shm_get_va() - Get virtual address of a shared memory plus an offset
280	* @shm: Shared memory handle
281	* @offs: Offset from start of this shared memory
282	* @returns virtual address of the shared memory + offs if offs is within
283	* the bounds of this shared memory, else an ERR_PTR
284	*/
285	void tee_shm_get_va(struct tee_shm shm, size_t offs)
286	{
287	if (offs >= shm->size)
288	return ERR_PTR(-EINVAL);
289	return (char *)shm->kaddr + offs;
290	}
291	EXPORT_SYMBOL_GPL(tee_shm_get_va);
292
293	/**
294	* tee_shm_get_pa() - Get physical address of a shared memory plus an offset
295	* @shm: Shared memory handle
296	* @offs: Offset from start of this shared memory
297	* @pa: Physical address to return
298	* @returns 0 if offs is within the bounds of this shared memory, else an
299	* error code.
300	*/
301	int tee_shm_get_pa(struct tee_shm shm, size_t offs, phys_addr_t pa)
302	{
303	if (offs >= shm->size)
304	return -EINVAL;
305	if (pa)
306	*pa = shm->paddr + offs;
307	return 0;
308	}
309	EXPORT_SYMBOL_GPL(tee_shm_get_pa);
310
311	/**
312	* tee_shm_get_from_id() - Find shared memory object and increase reference
313	* count
314	* @ctx: Context owning the shared memory
315	* @id: Id of shared memory object
316	* @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
317	*/
318	struct tee_shm tee_shm_get_from_id(struct tee_context ctx, int id)
319	{
320	struct tee_device *teedev;
321	struct tee_shm *shm;
322
323	if (!ctx)
324	return ERR_PTR(-EINVAL);
325
326	teedev = ctx->teedev;
327	mutex_lock(&teedev->mutex);
328	shm = idr_find(&teedev->idr, id);
329	if (!shm \|\| shm->ctx != ctx)
330	shm = ERR_PTR(-EINVAL);
331	else if (shm->flags & TEE_SHM_DMA_BUF)
332	get_dma_buf(shm->dmabuf);
333	mutex_unlock(&teedev->mutex);
334	return shm;
335	}
336	EXPORT_SYMBOL_GPL(tee_shm_get_from_id);
337
338	/**
339	* tee_shm_get_id() - Get id of a shared memory object
340	* @shm: Shared memory handle
341	* @returns id
342	*/
343	int tee_shm_get_id(struct tee_shm *shm)
344	{
345	return shm->id;
346	}
347	EXPORT_SYMBOL_GPL(tee_shm_get_id);
348
349	/**
350	* tee_shm_put() - Decrease reference count on a shared memory handle
351	* @shm: Shared memory handle
352	*/
353	void tee_shm_put(struct tee_shm *shm)
354	{
355	if (shm->flags & TEE_SHM_DMA_BUF)
356	dma_buf_put(shm->dmabuf);
357	}
358	EXPORT_SYMBOL_GPL(tee_shm_put);