tee: optee: add registered buffers handling into RPC calls

With latest changes to OP-TEE we can use any buffers as a shared memory.
Thus, it is possible for supplicant to provide part of own memory
when OP-TEE asks to allocate a shared buffer.

This patch adds support for such feature into RPC handling code.
Now when OP-TEE asks supplicant to allocate shared buffer, supplicant
can use TEE_IOC_SHM_REGISTER to provide such buffer. RPC handler is
aware of this, so it will pass list of allocated pages to OP-TEE.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
[jw: fix parenthesis alignment in free_pages_list()]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 68 insertions, 9 deletions

diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index cef417f4f4d2..690e48a61aca 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -200,7 +200,8 @@ static struct tee_shm *cmd_alloc_suppl(struct tee_context *ctx, size_t sz)
 }
 
 static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
-					  struct optee_msg_arg *arg)
+					  struct optee_msg_arg *arg,
+					  struct optee_call_ctx *call_ctx)
 {
 	phys_addr_t pa;
 	struct tee_shm *shm;
@@ -245,10 +246,49 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
 		goto bad;
 	}
 
-	arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
-	arg->params[0].u.tmem.buf_ptr = pa;
-	arg->params[0].u.tmem.size = sz;
-	arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+	sz = tee_shm_get_size(shm);
+
+	if (tee_shm_is_registered(shm)) {
+		struct page **pages;
+		u64 *pages_list;
+		size_t page_num;
+
+		pages = tee_shm_get_pages(shm, &page_num);
+		if (!pages || !page_num) {
+			arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
+			goto bad;
+		}
+
+		pages_list = optee_allocate_pages_list(page_num);
+		if (!pages_list) {
+			arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
+			goto bad;
+		}
+
+		call_ctx->pages_list = pages_list;
+		call_ctx->num_entries = page_num;
+
+		arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
+				      OPTEE_MSG_ATTR_NONCONTIG;
+		/*
+		 * In the least bits of u.tmem.buf_ptr we store buffer offset
+		 * from 4k page, as described in OP-TEE ABI.
+		 */
+		arg->params[0].u.tmem.buf_ptr = virt_to_phys(pages_list) |
+			(tee_shm_get_page_offset(shm) &
+			 (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));
+		arg->params[0].u.tmem.size = tee_shm_get_size(shm);
+		arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+
+		optee_fill_pages_list(pages_list, pages, page_num,
+				      tee_shm_get_page_offset(shm));
+	} else {
+		arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
+		arg->params[0].u.tmem.buf_ptr = pa;
+		arg->params[0].u.tmem.size = sz;
+		arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
+	}
+
 	arg->ret = TEEC_SUCCESS;
 	return;
 bad:
@@ -307,8 +347,24 @@ static void handle_rpc_func_cmd_shm_free(struct tee_context *ctx,
 	arg->ret = TEEC_SUCCESS;
 }
 
+static void free_pages_list(struct optee_call_ctx *call_ctx)
+{
+	if (call_ctx->pages_list) {
+		optee_free_pages_list(call_ctx->pages_list,
+				      call_ctx->num_entries);
+		call_ctx->pages_list = NULL;
+		call_ctx->num_entries = 0;
+	}
+}
+
+void optee_rpc_finalize_call(struct optee_call_ctx *call_ctx)
+{
+	free_pages_list(call_ctx);
+}
+
 static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
-				struct tee_shm *shm)
+				struct tee_shm *shm,
+				struct optee_call_ctx *call_ctx)
 {
 	struct optee_msg_arg *arg;
 
@@ -329,7 +385,8 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
 		handle_rpc_func_cmd_wait(arg);
 		break;
 	case OPTEE_MSG_RPC_CMD_SHM_ALLOC:
-		handle_rpc_func_cmd_shm_alloc(ctx, arg);
+		free_pages_list(call_ctx);
+		handle_rpc_func_cmd_shm_alloc(ctx, arg, call_ctx);
 		break;
 	case OPTEE_MSG_RPC_CMD_SHM_FREE:
 		handle_rpc_func_cmd_shm_free(ctx, arg);
@@ -343,10 +400,12 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
  * optee_handle_rpc() - handle RPC from secure world
  * @ctx:	context doing the RPC
  * @param:	value of registers for the RPC
+ * @call_ctx:	call context. Preserved during one OP-TEE invocation
  *
  * Result of RPC is written back into @param.
  */
-void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param)
+void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,
+		      struct optee_call_ctx *call_ctx)
 {
 	struct tee_device *teedev = ctx->teedev;
 	struct optee *optee = tee_get_drvdata(teedev);
@@ -381,7 +440,7 @@ void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param)
 		break;
 	case OPTEE_SMC_RPC_FUNC_CMD:
 		shm = reg_pair_to_ptr(param->a1, param->a2);
-		handle_rpc_func_cmd(ctx, optee, shm);
+		handle_rpc_func_cmd(ctx, optee, shm, call_ctx);
 		break;
 	default:
 		pr_warn("Unknown RPC func 0x%x\n",