[PATCH v2] optee: allow to work without static shared memory

[Volodymyr Babchuk <volodymyr_babchuk@epam.com>]

From: Volodymyr Babchuk <vlad.babchuk@gmail.com>

On virtualized systems it is possible that OP-TEE will provide
only dynamic shared memory support. So it is fine to boot
without static SHM enabled if dymanic one is supported.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
---

 Changes from v1:
   Patch is now can be applied to vanilla kernel instead of
   linaro's op-tee branch

 drivers/tee/optee/core.c | 80 +++++++++++++++++++++++++++++-------------------
 1 file changed, 49 insertions(+), 31 deletions(-)

diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index e1aafe8..efd2e5c 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -419,9 +419,35 @@ static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn,
 	return true;
 }
 
+static struct tee_shm_pool *optee_config_dyn_shm(void)
+{
+	struct tee_shm_pool_mgr *priv_mgr;
+	struct tee_shm_pool_mgr *dmabuf_mgr;
+	void *rc;
+
+	rc = optee_shm_pool_alloc_pages();
+	if (IS_ERR(rc))
+		return rc;
+	priv_mgr = rc;
+
+	rc = optee_shm_pool_alloc_pages();
+	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;
+}
+
 static struct tee_shm_pool *
-optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm,
-			  u32 sec_caps)
+optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm)
 {
 	union {
 		struct arm_smccc_res smccc;
@@ -436,10 +462,11 @@ optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm,
 	struct tee_shm_pool_mgr *priv_mgr;
 	struct tee_shm_pool_mgr *dmabuf_mgr;
 	void *rc;
+	const int sz = OPTEE_SHM_NUM_PRIV_PAGES * PAGE_SIZE;
 
 	invoke_fn(OPTEE_SMC_GET_SHM_CONFIG, 0, 0, 0, 0, 0, 0, 0, &res.smccc);
 	if (res.result.status != OPTEE_SMC_RETURN_OK) {
-		pr_info("shm service not available\n");
+		pr_err("static shm service not available\n");
 		return ERR_PTR(-ENOENT);
 	}
 
@@ -465,28 +492,15 @@ optee_config_shm_memremap(optee_invoke_fn *invoke_fn, void **memremaped_shm,
 	}
 	vaddr = (unsigned long)va;
 
-	/*
-	 * If OP-TEE can work with unregistered SHM, we will use own pool
-	 * for private shm
-	 */
-	if (sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM) {
-		rc = optee_shm_pool_alloc_pages();
-		if (IS_ERR(rc))
-			goto err_memunmap;
-		priv_mgr = rc;
-	} else {
-		const size_t sz = OPTEE_SHM_NUM_PRIV_PAGES * PAGE_SIZE;
-
-		rc = tee_shm_pool_mgr_alloc_res_mem(vaddr, paddr, sz,
-						    3 /* 8 bytes aligned */);
-		if (IS_ERR(rc))
-			goto err_memunmap;
-		priv_mgr = rc;
-
-		vaddr += sz;
-		paddr += sz;
-		size -= sz;
-	}
+	rc = tee_shm_pool_mgr_alloc_res_mem(vaddr, paddr, sz,
+					    3 /* 8 bytes aligned */);
+	if (IS_ERR(rc))
+		goto err_memunmap;
+	priv_mgr = rc;
+
+	vaddr += sz;
+	paddr += sz;
+	size -= sz;
 
 	rc = tee_shm_pool_mgr_alloc_res_mem(vaddr, paddr, size, PAGE_SHIFT);
 	if (IS_ERR(rc))
@@ -552,7 +566,7 @@ static optee_invoke_fn *get_invoke_func(struct device_node *np)
 static struct optee *optee_probe(struct device_node *np)
 {
 	optee_invoke_fn *invoke_fn;
-	struct tee_shm_pool *pool;
+	struct tee_shm_pool *pool = ERR_PTR(-EINVAL);
 	struct optee *optee = NULL;
 	void *memremaped_shm = NULL;
 	struct tee_device *teedev;
@@ -581,13 +595,17 @@ static struct optee *optee_probe(struct device_node *np)
 	}
 
 	/*
-	 * We have no other option for shared memory, if secure world
-	 * doesn't have any reserved memory we can use we can't continue.
+	 * Try to use dynamic shared memory if possible
 	 */
-	if (!(sec_caps & OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM))
-		return ERR_PTR(-EINVAL);
+	if (sec_caps & OPTEE_SMC_SEC_CAP_DYNAMIC_SHM)
+		pool = optee_config_dyn_shm();
+
+	/*
+	 * If dynamic shared memory is not available or failed - try static one
+	 */
+	if (IS_ERR(pool) && (sec_caps & OPTEE_SMC_SEC_CAP_HAVE_RESERVED_SHM))
+		pool = optee_config_shm_memremap(invoke_fn, &memremaped_shm);
 
-	pool = optee_config_shm_memremap(invoke_fn, &memremaped_shm, sec_caps);
 	if (IS_ERR(pool))
 		return (void *)pool;
 
-- 
2.7.4