tee: add AMD-TEE driver

Adds AMD-TEE driver.
* targets AMD APUs which has AMD Secure Processor with software-based
  Trusted Execution Environment (TEE) support
* registers with TEE subsystem
* defines tee_driver_ops function callbacks
* kernel allocated memory is used as shared memory between normal
  world and secure world.
* acts as REE (Rich Execution Environment) communication agent, which
  uses the services of AMD Secure Processor driver to submit commands
  for processing in TEE environment

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Co-developed-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@amd.com>
Signed-off-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Reviewed-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/tee/amdtee/shm_pool.c

@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright 2019 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/slab.h>
+#include <linux/tee_drv.h>
+#include <linux/psp-sev.h>
+#include "amdtee_private.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);
+	unsigned long va;
+	int rc;
+
+	va = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+	if (!va)
+		return -ENOMEM;
+
+	shm->kaddr = (void *)va;
+	shm->paddr = __psp_pa((void *)va);
+	shm->size = PAGE_SIZE << order;
+
+	/* Map the allocated memory in to TEE */
+	rc = amdtee_map_shmem(shm);
+	if (rc) {
+		free_pages(va, order);
+		shm->kaddr = NULL;
+		return rc;
+	}
+
+	return 0;
+}
+
+static void pool_op_free(struct tee_shm_pool_mgr *poolm, struct tee_shm *shm)
+{
+	/* Unmap the shared memory from TEE */
+	amdtee_unmap_shmem(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,
+};
+
+static struct tee_shm_pool_mgr *pool_mem_mgr_alloc(void)
+{
+	struct tee_shm_pool_mgr *mgr = kzalloc(sizeof(*mgr), GFP_KERNEL);
+
+	if (!mgr)
+		return ERR_PTR(-ENOMEM);
+
+	mgr->ops = &pool_ops;
+
+	return mgr;
+}
+
+struct tee_shm_pool *amdtee_config_shm(void)
+{
+	struct tee_shm_pool_mgr *priv_mgr;
+	struct tee_shm_pool_mgr *dmabuf_mgr;
+	void *rc;
+
+	rc = pool_mem_mgr_alloc();
+	if (IS_ERR(rc))
+		return rc;
+	priv_mgr = rc;
+
+	rc = pool_mem_mgr_alloc();
+	if (IS_ERR(rc)) {
+		tee_shm_pool_mgr_destroy(priv_mgr);
+		return rc;
+	}
+	dmabuf_mgr = rc;
+
+	rc = tee_shm_pool_alloc(priv_mgr, dmabuf_mgr);
+	if (IS_ERR(rc)) {
+		tee_shm_pool_mgr_destroy(priv_mgr);
+		tee_shm_pool_mgr_destroy(dmabuf_mgr);
+	}
+
+	return rc;
+}