tee: generic TEE subsystem

Initial patch for generic TEE subsystem.
This subsystem provides:
* Registration/un-registration of TEE drivers.
* Shared memory between normal world and secure world.
* Ioctl interface for interaction with user space.
* Sysfs implementation_id of TEE driver

A TEE (Trusted Execution Environment) driver is a driver that interfaces
with a trusted OS running in some secure environment, for example,
TrustZone on ARM cpus, or a separate secure co-processor etc.

The TEE subsystem can serve a TEE driver for a Global Platform compliant
TEE, but it's not limited to only Global Platform TEEs.

This patch builds on other similar implementations trying to solve
the same problem:
* "optee_linuxdriver" by among others
  Jean-michel DELORME<jean-michel.delorme@st.com> and
  Emmanuel MICHEL <emmanuel.michel@st.com>
* "Generic TrustZone Driver" by Javier González <javier@javigon.com>
Acked-by: NAndreas Dannenberg <dannenberg@ti.com>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org> (HiKey)
Tested-by: Volodymyr Babchuk <vlad.babchuk@gmail.com> (RCAR H3)
Tested-by: NScott Branden <scott.branden@broadcom.com>
Reviewed-by: NJavier González <javier@javigon.com>
Signed-off-by: NJens Wiklander <jens.wiklander@linaro.org>

Documentation/ioctl/ioctl-number.txt

@@ -308,6 +308,7 @@ Code  Seq#(hex)	Include File		Comments
 0xA3	80-8F	Port ACL		in development:
 					<mailto:tlewis@mindspring.com>
 0xA3	90-9F	linux/dtlk.h
+0xA4	00-1F	uapi/linux/tee.h	Generic TEE subsystem
 0xAA	00-3F	linux/uapi/linux/userfaultfd.h
 0xAB	00-1F	linux/nbd.h
 0xAC	00-1F	linux/raw.h

MAINTAINERS

@@ -11086,6 +11086,13 @@ F:	drivers/hwtracing/stm/
 F:	include/linux/stm.h
 F:	include/uapi/linux/stm.h
 
+TEE SUBSYSTEM
+M:	Jens Wiklander <jens.wiklander@linaro.org>
+S:	Maintained
+F:	include/linux/tee_drv.h
+F:	include/uapi/linux/tee.h
+F:	drivers/tee/
+
 THUNDERBOLT DRIVER
 M:	Andreas Noever <andreas.noever@gmail.com>
 S:	Maintained

drivers/Kconfig

@@ -204,4 +204,6 @@ source "drivers/fpga/Kconfig"
 
 source "drivers/fsi/Kconfig"
 
+source "drivers/tee/Kconfig"
+
 endmenu

drivers/Makefile

@@ -177,3 +177,4 @@ obj-$(CONFIG_ANDROID)		+= android/
 obj-$(CONFIG_NVMEM)		+= nvmem/
 obj-$(CONFIG_FPGA)		+= fpga/
 obj-$(CONFIG_FSI)		+= fsi/
+obj-$(CONFIG_TEE)		+= tee/

drivers/tee/Kconfig

+# Generic Trusted Execution Environment Configuration
+config TEE
+	tristate "Trusted Execution Environment support"
+	select DMA_SHARED_BUFFER
+	select GENERIC_ALLOCATOR
+	help
+	  This implements a generic interface towards a Trusted Execution
+	  Environment (TEE).

drivers/tee/Makefile

+obj-$(CONFIG_TEE) += tee.o
+tee-objs += tee_core.o
+tee-objs += tee_shm.o
+tee-objs += tee_shm_pool.o

drivers/tee/tee_private.h

+/*
+ * 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.
+ *
+ */
+#ifndef TEE_PRIVATE_H
+#define TEE_PRIVATE_H
+
+#include <linux/cdev.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/kref.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+struct tee_device;
+
+/**
+ * struct tee_shm - shared memory object
+ * @teedev:	device used to allocate the object
+ * @ctx:	context using the object, if NULL the context is gone
+ * @link	link element
+ * @paddr:	physical address of the shared memory
+ * @kaddr:	virtual address of the shared memory
+ * @size:	size of shared memory
+ * @dmabuf:	dmabuf used to for exporting to user space
+ * @flags:	defined by TEE_SHM_* in tee_drv.h
+ * @id:		unique id of a shared memory object on this device
+ */
+struct tee_shm {
+	struct tee_device *teedev;
+	struct tee_context *ctx;
+	struct list_head link;
+	phys_addr_t paddr;
+	void *kaddr;
+	size_t size;
+	struct dma_buf *dmabuf;
+	u32 flags;
+	int id;
+};
+
+struct tee_shm_pool_mgr;
+
+/**
+ * struct tee_shm_pool_mgr_ops - shared memory pool manager operations
+ * @alloc:	called when allocating shared memory
+ * @free:	called when freeing shared memory
+ */
+struct tee_shm_pool_mgr_ops {
+	int (*alloc)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm,
+		     size_t size);
+	void (*free)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm);
+};
+
+/**
+ * struct tee_shm_pool_mgr - shared memory manager
+ * @ops:		operations
+ * @private_data:	private data for the shared memory manager
+ */
+struct tee_shm_pool_mgr {
+	const struct tee_shm_pool_mgr_ops *ops;
+	void *private_data;
+};
+
+/**
+ * struct tee_shm_pool - shared memory pool
+ * @private_mgr:	pool manager for shared memory only between kernel
+ *			and secure world
+ * @dma_buf_mgr:	pool manager for shared memory exported to user space
+ * @destroy:		called when destroying the pool
+ * @private_data:	private data for the pool
+ */
+struct tee_shm_pool {
+	struct tee_shm_pool_mgr private_mgr;
+	struct tee_shm_pool_mgr dma_buf_mgr;
+	void (*destroy)(struct tee_shm_pool *pool);
+	void *private_data;
+};
+
+#define TEE_DEVICE_FLAG_REGISTERED	0x1
+#define TEE_MAX_DEV_NAME_LEN		32
+
+/**
+ * struct tee_device - TEE Device representation
+ * @name:	name of device
+ * @desc:	description of device
+ * @id:		unique id of device
+ * @flags:	represented by TEE_DEVICE_FLAG_REGISTERED above
+ * @dev:	embedded basic device structure
+ * @cdev:	embedded cdev
+ * @num_users:	number of active users of this device
+ * @c_no_user:	completion used when unregistering the device
+ * @mutex:	mutex protecting @num_users and @idr
+ * @idr:	register of shared memory object allocated on this device
+ * @pool:	shared memory pool
+ */
+struct tee_device {
+	char name[TEE_MAX_DEV_NAME_LEN];
+	const struct tee_desc *desc;
+	int id;
+	unsigned int flags;
+
+	struct device dev;
+	struct cdev cdev;
+
+	size_t num_users;
+	struct completion c_no_users;
+	struct mutex mutex;	/* protects num_users and idr */
+
+	struct idr idr;
+	struct tee_shm_pool *pool;
+};
+
+int tee_shm_init(void);
+
+int tee_shm_get_fd(struct tee_shm *shm);
+
+bool tee_device_get(struct tee_device *teedev);
+void tee_device_put(struct tee_device *teedev);
+
+#endif /*TEE_PRIVATE_H*/

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_kmap_atomic(struct dma_buf *dmabuf, unsigned long pgnum)
+{
+	return NULL;
+}
+
+static void *tee_shm_op_kmap(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 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,
+	.kmap_atomic = tee_shm_op_kmap_atomic,
+	.kmap = tee_shm_op_kmap,
+	.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);

drivers/tee/tee_shm_pool.c

+/*
+ * Copyright (c) 2015, 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/genalloc.h>
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include "tee_private.h"
+
+static int pool_op_gen_alloc(struct tee_shm_pool_mgr *poolm,
+			     struct tee_shm *shm, size_t size)
+{
+	unsigned long va;
+	struct gen_pool *genpool = poolm->private_data;
+	size_t s = roundup(size, 1 << genpool->min_alloc_order);
+
+	va = gen_pool_alloc(genpool, s);
+	if (!va)
+		return -ENOMEM;
+
+	memset((void *)va, 0, s);
+	shm->kaddr = (void *)va;
+	shm->paddr = gen_pool_virt_to_phys(genpool, va);
+	shm->size = s;
+	return 0;
+}
+
+static void pool_op_gen_free(struct tee_shm_pool_mgr *poolm,
+			     struct tee_shm *shm)
+{
+	gen_pool_free(poolm->private_data, (unsigned long)shm->kaddr,
+		      shm->size);
+	shm->kaddr = NULL;
+}
+
+static const struct tee_shm_pool_mgr_ops pool_ops_generic = {
+	.alloc = pool_op_gen_alloc,
+	.free = pool_op_gen_free,
+};
+
+static void pool_res_mem_destroy(struct tee_shm_pool *pool)
+{
+	gen_pool_destroy(pool->private_mgr.private_data);
+	gen_pool_destroy(pool->dma_buf_mgr.private_data);
+}
+
+static int pool_res_mem_mgr_init(struct tee_shm_pool_mgr *mgr,
+				 struct tee_shm_pool_mem_info *info,
+				 int min_alloc_order)
+{
+	size_t page_mask = PAGE_SIZE - 1;
+	struct gen_pool *genpool = NULL;
+	int rc;
+
+	/*
+	 * Start and end must be page aligned
+	 */
+	if ((info->vaddr & page_mask) || (info->paddr & page_mask) ||
+	    (info->size & page_mask))
+		return -EINVAL;
+
+	genpool = gen_pool_create(min_alloc_order, -1);
+	if (!genpool)
+		return -ENOMEM;
+
+	gen_pool_set_algo(genpool, gen_pool_best_fit, NULL);
+	rc = gen_pool_add_virt(genpool, info->vaddr, info->paddr, info->size,
+			       -1);
+	if (rc) {
+		gen_pool_destroy(genpool);
+		return rc;
+	}
+
+	mgr->private_data = genpool;
+	mgr->ops = &pool_ops_generic;
+	return 0;
+}
+
+/**
+ * tee_shm_pool_alloc_res_mem() - Create a shared memory pool from reserved
+ * memory range
+ * @priv_info:	Information for driver private shared memory pool
+ * @dmabuf_info: Information for dma-buf shared memory pool
+ *
+ * Start and end of pools will must be page aligned.
+ *
+ * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
+ * in @dmabuf, others will use the range provided by @priv.
+ *
+ * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
+ */
+struct tee_shm_pool *
+tee_shm_pool_alloc_res_mem(struct tee_shm_pool_mem_info *priv_info,
+			   struct tee_shm_pool_mem_info *dmabuf_info)
+{
+	struct tee_shm_pool *pool = NULL;
+	int ret;
+
+	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
+	if (!pool) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/*
+	 * Create the pool for driver private shared memory
+	 */
+	ret = pool_res_mem_mgr_init(&pool->private_mgr, priv_info,
+				    3 /* 8 byte aligned */);
+	if (ret)
+		goto err;
+
+	/*
+	 * Create the pool for dma_buf shared memory
+	 */
+	ret = pool_res_mem_mgr_init(&pool->dma_buf_mgr, dmabuf_info,
+				    PAGE_SHIFT);
+	if (ret)
+		goto err;
+
+	pool->destroy = pool_res_mem_destroy;
+	return pool;
+err:
+	if (ret == -ENOMEM)
+		pr_err("%s: can't allocate memory for res_mem shared memory pool\n", __func__);
+	if (pool && pool->private_mgr.private_data)
+		gen_pool_destroy(pool->private_mgr.private_data);
+	kfree(pool);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(tee_shm_pool_alloc_res_mem);
+
+/**
+ * tee_shm_pool_free() - Free a shared memory pool
+ * @pool:	The shared memory pool to free
+ *
+ * There must be no remaining shared memory allocated from this pool when
+ * this function is called.
+ */
+void tee_shm_pool_free(struct tee_shm_pool *pool)
+{
+	pool->destroy(pool);
+	kfree(pool);
+}
+EXPORT_SYMBOL_GPL(tee_shm_pool_free);

include/linux/tee_drv.h

+/*
+ * 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.
+ *
+ */
+
+#ifndef __TEE_DRV_H
+#define __TEE_DRV_H
+
+#include <linux/types.h>
+#include <linux/idr.h>
+#include <linux/list.h>
+#include <linux/tee.h>
+
+/*
+ * The file describes the API provided by the generic TEE driver to the
+ * specific TEE driver.
+ */
+
+#define TEE_SHM_MAPPED		0x1	/* Memory mapped by the kernel */
+#define TEE_SHM_DMA_BUF		0x2	/* Memory with dma-buf handle */
+
+struct tee_device;
+struct tee_shm;
+struct tee_shm_pool;
+
+/**
+ * struct tee_context - driver specific context on file pointer data
+ * @teedev:	pointer to this drivers struct tee_device
+ * @list_shm:	List of shared memory object owned by this context
+ * @data:	driver specific context data, managed by the driver
+ */
+struct tee_context {
+	struct tee_device *teedev;
+	struct list_head list_shm;
+	void *data;
+};
+
+struct tee_param_memref {
+	size_t shm_offs;
+	size_t size;
+	struct tee_shm *shm;
+};
+
+struct tee_param_value {
+	u64 a;
+	u64 b;
+	u64 c;
+};
+
+struct tee_param {
+	u64 attr;
+	union {
+		struct tee_param_memref memref;
+		struct tee_param_value value;
+	} u;
+};
+
+/**
+ * struct tee_driver_ops - driver operations vtable
+ * @get_version:	returns version of driver
+ * @open:		called when the device file is opened
+ * @release:		release this open file
+ * @open_session:	open a new session
+ * @close_session:	close a session
+ * @invoke_func:	invoke a trusted function
+ * @cancel_req:		request cancel of an ongoing invoke or open
+ * @supp_revc:		called for supplicant to get a command
+ * @supp_send:		called for supplicant to send a response
+ */
+struct tee_driver_ops {
+	void (*get_version)(struct tee_device *teedev,
+			    struct tee_ioctl_version_data *vers);
+	int (*open)(struct tee_context *ctx);
+	void (*release)(struct tee_context *ctx);
+	int (*open_session)(struct tee_context *ctx,
+			    struct tee_ioctl_open_session_arg *arg,
+			    struct tee_param *param);
+	int (*close_session)(struct tee_context *ctx, u32 session);
+	int (*invoke_func)(struct tee_context *ctx,
+			   struct tee_ioctl_invoke_arg *arg,
+			   struct tee_param *param);
+	int (*cancel_req)(struct tee_context *ctx, u32 cancel_id, u32 session);
+	int (*supp_recv)(struct tee_context *ctx, u32 *func, u32 *num_params,
+			 struct tee_param *param);
+	int (*supp_send)(struct tee_context *ctx, u32 ret, u32 num_params,
+			 struct tee_param *param);
+};
+
+/**
+ * struct tee_desc - Describes the TEE driver to the subsystem
+ * @name:	name of driver
+ * @ops:	driver operations vtable
+ * @owner:	module providing the driver
+ * @flags:	Extra properties of driver, defined by TEE_DESC_* below
+ */
+#define TEE_DESC_PRIVILEGED	0x1
+struct tee_desc {
+	const char *name;
+	const struct tee_driver_ops *ops;
+	struct module *owner;
+	u32 flags;
+};
+
+/**
+ * tee_device_alloc() - Allocate a new struct tee_device instance
+ * @teedesc:	Descriptor for this driver
+ * @dev:	Parent device for this device
+ * @pool:	Shared memory pool, NULL if not used
+ * @driver_data: Private driver data for this device
+ *
+ * Allocates a new struct tee_device instance. The device is
+ * removed by tee_device_unregister().
+ *
+ * @returns a pointer to a 'struct tee_device' or an ERR_PTR on failure
+ */
+struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
+				    struct device *dev,
+				    struct tee_shm_pool *pool,
+				    void *driver_data);
+
+/**
+ * tee_device_register() - Registers a TEE device
+ * @teedev:	Device to register
+ *
+ * tee_device_unregister() need to be called to remove the @teedev if
+ * this function fails.
+ *
+ * @returns < 0 on failure
+ */
+int tee_device_register(struct tee_device *teedev);
+
+/**
+ * tee_device_unregister() - Removes a TEE device
+ * @teedev:	Device to unregister
+ *
+ * This function should be called to remove the @teedev even if
+ * tee_device_register() hasn't been called yet. Does nothing if
+ * @teedev is NULL.
+ */
+void tee_device_unregister(struct tee_device *teedev);
+
+/**
+ * struct tee_shm_pool_mem_info - holds information needed to create a shared
+ * memory pool
+ * @vaddr:	Virtual address of start of pool
+ * @paddr:	Physical address of start of pool
+ * @size:	Size in bytes of the pool
+ */
+struct tee_shm_pool_mem_info {
+	unsigned long vaddr;
+	phys_addr_t paddr;
+	size_t size;
+};
+
+/**
+ * tee_shm_pool_alloc_res_mem() - Create a shared memory pool from reserved
+ * memory range
+ * @priv_info:	 Information for driver private shared memory pool
+ * @dmabuf_info: Information for dma-buf shared memory pool
+ *
+ * Start and end of pools will must be page aligned.
+ *
+ * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
+ * in @dmabuf, others will use the range provided by @priv.
+ *
+ * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
+ */
+struct tee_shm_pool *
+tee_shm_pool_alloc_res_mem(struct tee_shm_pool_mem_info *priv_info,
+			   struct tee_shm_pool_mem_info *dmabuf_info);
+
+/**
+ * tee_shm_pool_free() - Free a shared memory pool
+ * @pool:	The shared memory pool to free
+ *
+ * The must be no remaining shared memory allocated from this pool when
+ * this function is called.
+ */
+void tee_shm_pool_free(struct tee_shm_pool *pool);
+
+/**
+ * tee_get_drvdata() - Return driver_data pointer
+ * @returns the driver_data pointer supplied to tee_register().
+ */
+void *tee_get_drvdata(struct tee_device *teedev);
+
+/**
+ * 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_* above. 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.
+ *
+ * @returns a pointer to 'struct tee_shm'
+ */
+struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);
+
+/**
+ * tee_shm_free() - Free shared memory
+ * @shm:	Handle to shared memory to free
+ */
+void tee_shm_free(struct tee_shm *shm);
+
+/**
+ * tee_shm_put() - Decrease reference count on a shared memory handle
+ * @shm:	Shared memory handle
+ */
+void tee_shm_put(struct tee_shm *shm);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+#endif /*__TEE_DRV_H*/

include/uapi/linux/tee.h

+/*
+ * Copyright (c) 2015-2016, Linaro Limited
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __TEE_H
+#define __TEE_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/*
+ * This file describes the API provided by a TEE driver to user space.
+ *
+ * Each TEE driver defines a TEE specific protocol which is used for the
+ * data passed back and forth using TEE_IOC_CMD.
+ */
+
+/* Helpers to make the ioctl defines */
+#define TEE_IOC_MAGIC	0xa4
+#define TEE_IOC_BASE	0
+
+/* Flags relating to shared memory */
+#define TEE_IOCTL_SHM_MAPPED	0x1	/* memory mapped in normal world */
+#define TEE_IOCTL_SHM_DMA_BUF	0x2	/* dma-buf handle on shared memory */
+
+#define TEE_MAX_ARG_SIZE	1024
+
+#define TEE_GEN_CAP_GP		(1 << 0)/* GlobalPlatform compliant TEE */
+
+/*
+ * TEE Implementation ID
+ */
+#define TEE_IMPL_ID_OPTEE	1
+
+/*
+ * OP-TEE specific capabilities
+ */
+#define TEE_OPTEE_CAP_TZ	(1 << 0)
+
+/**
+ * struct tee_ioctl_version_data - TEE version
+ * @impl_id:	[out] TEE implementation id
+ * @impl_caps:	[out] Implementation specific capabilities
+ * @gen_caps:	[out] Generic capabilities, defined by TEE_GEN_CAPS_* above
+ *
+ * Identifies the TEE implementation, @impl_id is one of TEE_IMPL_ID_* above.
+ * @impl_caps is implementation specific, for example TEE_OPTEE_CAP_*
+ * is valid when @impl_id == TEE_IMPL_ID_OPTEE.
+ */
+struct tee_ioctl_version_data {
+	__u32 impl_id;
+	__u32 impl_caps;
+	__u32 gen_caps;
+};
+
+/**
+ * TEE_IOC_VERSION - query version of TEE
+ *
+ * Takes a tee_ioctl_version_data struct and returns with the TEE version
+ * data filled in.
+ */
+#define TEE_IOC_VERSION		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 0, \
+				     struct tee_ioctl_version_data)
+
+/**
+ * struct tee_ioctl_shm_alloc_data - Shared memory allocate argument
+ * @size:	[in/out] Size of shared memory to allocate
+ * @flags:	[in/out] Flags to/from allocation.
+ * @id:		[out] Identifier of the shared memory
+ *
+ * The flags field should currently be zero as input. Updated by the call
+ * with actual flags as defined by TEE_IOCTL_SHM_* above.
+ * This structure is used as argument for TEE_IOC_SHM_ALLOC below.
+ */
+struct tee_ioctl_shm_alloc_data {
+	__u64 size;
+	__u32 flags;
+	__s32 id;
+};
+
+/**
+ * TEE_IOC_SHM_ALLOC - allocate shared memory
+ *
+ * Allocates shared memory between the user space process and secure OS.
+ *
+ * Returns a file descriptor on success or < 0 on failure
+ *
+ * The returned file descriptor is used to map the shared memory into user
+ * space. The shared memory is freed when the descriptor is closed and the
+ * memory is unmapped.
+ */
+#define TEE_IOC_SHM_ALLOC	_IOWR(TEE_IOC_MAGIC, TEE_IOC_BASE + 1, \
+				     struct tee_ioctl_shm_alloc_data)
+
+/**
+ * struct tee_ioctl_buf_data - Variable sized buffer
+ * @buf_ptr:	[in] A __user pointer to a buffer
+ * @buf_len:	[in] Length of the buffer above
+ *
+ * Used as argument for TEE_IOC_OPEN_SESSION, TEE_IOC_INVOKE,
+ * TEE_IOC_SUPPL_RECV, and TEE_IOC_SUPPL_SEND below.
+ */
+struct tee_ioctl_buf_data {
+	__u64 buf_ptr;
+	__u64 buf_len;
+};
+
+/*
+ * Attributes for struct tee_ioctl_param, selects field in the union
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_NONE		0	/* parameter not used */
+
+/*
+ * These defines value parameters (struct tee_ioctl_param_value)
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT	1
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT	2
+#define TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT	3	/* input and output */
+
+/*
+ * These defines shared memory reference parameters (struct
+ * tee_ioctl_param_memref)
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT	5
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT	6
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT	7	/* input and output */
+
+/*
+ * Mask for the type part of the attribute, leaves room for more types
+ */
+#define TEE_IOCTL_PARAM_ATTR_TYPE_MASK		0xff
+
+/*
+ * Matches TEEC_LOGIN_* in GP TEE Client API
+ * Are only defined for GP compliant TEEs
+ */
+#define TEE_IOCTL_LOGIN_PUBLIC			0
+#define TEE_IOCTL_LOGIN_USER			1
+#define TEE_IOCTL_LOGIN_GROUP			2
+#define TEE_IOCTL_LOGIN_APPLICATION		4
+#define TEE_IOCTL_LOGIN_USER_APPLICATION	5
+#define TEE_IOCTL_LOGIN_GROUP_APPLICATION	6
+
+/**
+ * struct tee_ioctl_param - parameter
+ * @attr: attributes
+ * @a: if a memref, offset into the shared memory object, else a value parameter
+ * @b: if a memref, size of the buffer, else a value parameter
+ * @c: if a memref, shared memory identifier, else a value parameter
+ *
+ * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref or value is used in
+ * the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value and
+ * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref. TEE_PARAM_ATTR_TYPE_NONE
+ * indicates that none of the members are used.
+ *
+ * Shared memory is allocated with TEE_IOC_SHM_ALLOC which returns an
+ * identifier representing the shared memory object. A memref can reference
+ * a part of a shared memory by specifying an offset (@a) and size (@b) of
+ * the object. To supply the entire shared memory object set the offset
+ * (@a) to 0 and size (@b) to the previously returned size of the object.
+ */
+struct tee_ioctl_param {
+	__u64 attr;
+	__u64 a;
+	__u64 b;
+	__u64 c;
+};
+
+#define TEE_IOCTL_UUID_LEN		16
+
+/**
+ * struct tee_ioctl_open_session_arg - Open session argument
+ * @uuid:	[in] UUID of the Trusted Application
+ * @clnt_uuid:	[in] UUID of client
+ * @clnt_login:	[in] Login class of client, TEE_IOCTL_LOGIN_* above
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @session:	[out] Session id
+ * @ret:	[out] return value
+ * @ret_origin	[out] origin of the return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_ioctl_open_session_arg {
+	__u8 uuid[TEE_IOCTL_UUID_LEN];
+	__u8 clnt_uuid[TEE_IOCTL_UUID_LEN];
+	__u32 clnt_login;
+	__u32 cancel_id;
+	__u32 session;
+	__u32 ret;
+	__u32 ret_origin;
+	__u32 num_params;
+	/* num_params tells the actual number of element in params */
+	struct tee_ioctl_param params[];
+};
+
+/**
+ * TEE_IOC_OPEN_SESSION - opens a session to a Trusted Application
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_ioctl_open_session_arg followed by any array of struct
+ * tee_ioctl_param
+ */
+#define TEE_IOC_OPEN_SESSION	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 2, \
+				     struct tee_ioctl_buf_data)
+
+/**
+ * struct tee_ioctl_invoke_func_arg - Invokes a function in a Trusted
+ * Application
+ * @func:	[in] Trusted Application function, specific to the TA
+ * @session:	[in] Session id
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @ret:	[out] return value
+ * @ret_origin	[out] origin of the return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_ioctl_invoke_arg {
+	__u32 func;
+	__u32 session;
+	__u32 cancel_id;
+	__u32 ret;
+	__u32 ret_origin;
+	__u32 num_params;
+	/* num_params tells the actual number of element in params */
+	struct tee_ioctl_param params[];
+};
+
+/**
+ * TEE_IOC_INVOKE - Invokes a function in a Trusted Application
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_invoke_func_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_INVOKE		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 3, \
+				     struct tee_ioctl_buf_data)
+
+/**
+ * struct tee_ioctl_cancel_arg - Cancels an open session or invoke ioctl
+ * @cancel_id:	[in] Cancellation id, a unique value to identify this request
+ * @session:	[in] Session id, if the session is opened, else set to 0
+ */
+struct tee_ioctl_cancel_arg {
+	__u32 cancel_id;
+	__u32 session;
+};
+
+/**
+ * TEE_IOC_CANCEL - Cancels an open session or invoke
+ */
+#define TEE_IOC_CANCEL		_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 4, \
+				     struct tee_ioctl_cancel_arg)
+
+/**
+ * struct tee_ioctl_close_session_arg - Closes an open session
+ * @session:	[in] Session id
+ */
+struct tee_ioctl_close_session_arg {
+	__u32 session;
+};
+
+/**
+ * TEE_IOC_CLOSE_SESSION - Closes a session
+ */
+#define TEE_IOC_CLOSE_SESSION	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 5, \
+				     struct tee_ioctl_close_session_arg)
+
+/**
+ * struct tee_iocl_supp_recv_arg - Receive a request for a supplicant function
+ * @func:	[in] supplicant function
+ * @num_params	[in/out] number of parameters following this struct
+ *
+ * @num_params is the number of params that tee-supplicant has room to
+ * receive when input, @num_params is the number of actual params
+ * tee-supplicant receives when output.
+ */
+struct tee_iocl_supp_recv_arg {
+	__u32 func;
+	__u32 num_params;
+	/* num_params tells the actual number of element in params */
+	struct tee_ioctl_param params[];
+};
+
+/**
+ * TEE_IOC_SUPPL_RECV - Receive a request for a supplicant function
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_iocl_supp_recv_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_SUPPL_RECV	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 6, \
+				     struct tee_ioctl_buf_data)
+
+/**
+ * struct tee_iocl_supp_send_arg - Send a response to a received request
+ * @ret:	[out] return value
+ * @num_params	[in] number of parameters following this struct
+ */
+struct tee_iocl_supp_send_arg {
+	__u32 ret;
+	__u32 num_params;
+	/* num_params tells the actual number of element in params */
+	struct tee_ioctl_param params[];
+};
+
+/**
+ * TEE_IOC_SUPPL_SEND - Receive a request for a supplicant function
+ *
+ * Takes a struct tee_ioctl_buf_data which contains a struct
+ * tee_iocl_supp_send_arg followed by any array of struct tee_param
+ */
+#define TEE_IOC_SUPPL_SEND	_IOR(TEE_IOC_MAGIC, TEE_IOC_BASE + 7, \
+				     struct tee_ioctl_buf_data)
+
+/*
+ * Five syscalls are used when communicating with the TEE driver.
+ * open(): opens the device associated with the driver
+ * ioctl(): as described above operating on the file descriptor from open()
+ * close(): two cases
+ *   - closes the device file descriptor
+ *   - closes a file descriptor connected to allocated shared memory
+ * mmap(): maps shared memory into user space using information from struct
+ *	   tee_ioctl_shm_alloc_data
+ * munmap(): unmaps previously shared memory
+ */
+
+#endif /*__TEE_H*/