Merge tag 'tee-drv-dynamic-shm-for-v4.16' of https://git.linaro.org/people/jens.wiklander/linux-tee into next/drivers

Pull "tee dynamic shm for v4.16" from Jens Wiklander:

This pull request enables dynamic shared memory support in the TEE
subsystem as a whole and in OP-TEE in particular.

Global Platform TEE specification [1] allows client applications
to register part of own memory as a shared buffer between
application and TEE. This allows fast zero-copy communication between
TEE and REE. But current implementation of TEE in Linux does not support
this feature.

Also, current implementation of OP-TEE transport uses fixed size
pre-shared buffer for all communications with OP-TEE OS. This is okay
in the most use cases. But this prevents use of OP-TEE in virtualized
environments, because:
 a) We can't share the same buffer between different virtual machines
 b) Physically contiguous memory as seen by VM can be non-contiguous
    in reality (and as seen by OP-TEE OS) due to second stage of
    MMU translation.
 c) Size of this pre-shared buffer is limited.

So, first part of this pull request adds generic register/unregister
interface to tee subsystem. The second part adds necessary features into
OP-TEE driver, so it can use not only static pre-shared buffer, but
whole RAM to communicate with OP-TEE OS.

This change is backwards compatible allowing older secure world or
user space to work with newer kernels and vice versa.

[1] https://www.globalplatform.org/specificationsdevice.asp

* tag 'tee-drv-dynamic-shm-for-v4.16' of https://git.linaro.org/people/jens.wiklander/linux-tee:
  tee: shm: inline tee_shm_get_id()
  tee: use reference counting for tee_context
  tee: optee: enable dynamic SHM support
  tee: optee: add optee-specific shared pool implementation
  tee: optee: store OP-TEE capabilities in private data
  tee: optee: add registered buffers handling into RPC calls
  tee: optee: add registered shared parameters handling
  tee: optee: add shared buffer registration functions
  tee: optee: add page list manipulation functions
  tee: optee: Update protocol definitions
  tee: shm: add page accessor functions
  tee: shm: add accessors for buffer size and page offset
  tee: add register user memory
  tee: flexible shared memory pool creation

1 files changed, 75 insertions, 0 deletions

diff --git a/drivers/tee/optee/shm_pool.c b/drivers/tee/optee/shm_pool.c
new file mode 100644
index 000000000000..49397813fff1
--- /dev/null
+++ b/drivers/tee/optee/shm_pool.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ * Copyright (c) 2017, EPAM Systems
+ *
+ * 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 "optee_private.h"
+#include "optee_smc.h"
+#include "shm_pool.h"
+
+static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
+			 struct tee_shm *shm, size_t size)
+{
+	unsigned int order = get_order(size);
+	struct page *page;
+
+	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+	if (!page)
+		return -ENOMEM;
+
+	shm->kaddr = page_address(page);
+	shm->paddr = page_to_phys(page);
+	shm->size = PAGE_SIZE << order;
+
+	return 0;
+}
+
+static void pool_op_free(struct tee_shm_pool_mgr *poolm,
+			 struct tee_shm *shm)
+{
+	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
+	shm->kaddr = NULL;
+}
+
+static void pool_op_destroy_poolmgr(struct tee_shm_pool_mgr *poolm)
+{
+	kfree(poolm);
+}
+
+static const struct tee_shm_pool_mgr_ops pool_ops = {
+	.alloc = pool_op_alloc,
+	.free = pool_op_free,
+	.destroy_poolmgr = pool_op_destroy_poolmgr,
+};
+
+/**
+ * optee_shm_pool_alloc_pages() - create page-based allocator pool
+ *
+ * This pool is used when OP-TEE supports dymanic SHM. In this case
+ * command buffers and such are allocated from kernel's own memory.
+ */
+struct tee_shm_pool_mgr *optee_shm_pool_alloc_pages(void)
+{
+	struct tee_shm_pool_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
+
+	if (!mgr)
+		return ERR_PTR(-ENOMEM);
+
+	mgr->ops = &pool_ops;
+
+	return mgr;
+}