libteec: Move OP-TEE defined fields into an imp struct

GlobalPlatform TEE Client API Specification v1.0 specifies that
the structs TEEC_Context, TEEC_Session, TEEC_SharedMemory,
and TEEC_Operation shall have a user defined struct named imp.
In OP-TEE the struct is not there and instead the user defined
fields are declared directly in the top structs.
This commit introduces the imp struct to better support using
different implementations. The imp fields now represent the
implementation defined parts of the structs that was
previously declared directly in the top struct. All previously
available parameters are preserved in the imp struct.
The updated version of the imp structure makes it easier to
create a binding for Rust.
Adding the missing imp struct to the structs in OP-TEE is an
ABI breakage which requires a version major update of libteec.

Link: #348
Reported-by: Tom Hebb <tommyhebb@gmail.com>
Signed-off-by: Julianus Larson <julianus.larson@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@foss.st.com>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>

libteec/CMakeLists.txt

@@ -1,5 +1,5 @@
 project(libteec
-	VERSION 1.0.0
+	VERSION 2.0.0
 	LANGUAGES C)
 
 ################################################################################

libteec/Makefile

@@ -9,7 +9,7 @@ all: libteec
 ################################################################################
 # Teec configuration
 ################################################################################
-MAJOR_VERSION	:= 1
+MAJOR_VERSION	:= 2
 MINOR_VERSION	:= 0
 PATCH_VERSION	:= 0
 LIB_NAME	:= libteec.so

libteec/include/tee_client_api.h

@@ -276,9 +276,11 @@ typedef uint32_t TEEC_Result;
  */
 typedef struct {
 	/* Implementation defined */
-	int fd;
-	bool reg_mem;
-	bool memref_null;
+	struct {
+		int fd;
+		bool reg_mem;
+		bool memref_null;
+	} imp;
 } TEEC_Context;
 
 /**
@@ -314,16 +316,15 @@ typedef struct {
 	size_t size;
 	uint32_t flags;
 	/*
-	 * Implementation-Defined
+	 * Implementation defined
 	 */
-	int id;
-	size_t alloced_size;
-	void *shadow_buffer;
-	int registered_fd;
-	union {
-		bool dummy;
-		uint8_t flags;
-	} internal;
+	struct {
+		int id;
+		size_t alloced_size;
+		void *shadow_buffer;
+		int registered_fd;
+		uint32_t flags;
+	} imp;
 } TEEC_SharedMemory;
 
 /**
@@ -405,8 +406,10 @@ typedef union {
  */
 typedef struct {
 	/* Implementation defined */
-	TEEC_Context *ctx;
-	uint32_t session_id;
+	struct {
+		TEEC_Context *ctx;
+		uint32_t session_id;
+	} imp;
 } TEEC_Session;
 
 /**
@@ -419,16 +422,20 @@ typedef struct {
  *                      create the correct flags.
  *                      0 means TEEC_NONE is passed for all params.
  * @param   params      Array of parameters of type TEEC_Parameter.
- * @param   session     Internal pointer to the last session used by
+ * @param   imp         Implementation defined parameter. Here it is a struct
+ *                      containing one parameter: session. session is an
+ *                      internal pointer to the last session used by
  *                      TEEC_InvokeCommand with this operation.
  *
  */
 typedef struct {
 	uint32_t started;
 	uint32_t paramTypes;
 	TEEC_Parameter params[TEEC_CONFIG_PAYLOAD_REF_COUNT];
-	/* Implementation-Defined */
-	TEEC_Session *session;
+	/* Implementation defined */
+	struct {
+		TEEC_Session *session;
+	} imp;
 } TEEC_Operation;
 
 /**