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: Andreas 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: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 156 insertions, 0 deletions

diff --git a/drivers/tee/tee_shm_pool.c b/drivers/tee/tee_shm_pool.c
new file mode 100644
index 000000000000..fb4f8522a526
--- /dev/null
+++ b/drivers/tee/tee_shm_pool.c
@@ -0,0 +1,156 @@
+/*
+ * 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);