optee CA和TA 例程 - 值传递

CA

如下实现一个简单的CA代码示例，它使用了不同的Params类型

#include <err.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* OP-TEE TEE client API (built by optee_client) */
#include <tee_client_api.h>

/* To the the UUID (found the the TA's h-file(s)) */
#include <hello_world_ta.h>

#define CMD_TEST_VALUE  0x001 
#define CMD_TEST_BUFFER 0x002
#define TA_HELLO_WORLD_UUID  { 0xc02ffd4f, 0xa7a3, 0xb1c3,
									{ 0x92, 0x08, 0x37, 0x06, 0xe4, 0xc8, 0xb1, 0xaf } }
int main(int argc ,char **argv)
{
        TEEC_Result res;
        TEEC_Context ctx;
        TEEC_Session sess;
        TEEC_Operation op;
        TEEC_UUID uuid = TA_HELLO_WORLD_UUID;
        uint32_t err_origin;

        /* Initialize a context connecting us to the TEE */
        res = TEEC_InitializeContext(NULL, &ctx);
        if (res != TEEC_SUCCESS)
                errx(1, "TEEC_InitializeContext failed with code 0x%x", res);

        /*
         * Open a session
         */
        res = TEEC_OpenSession(&ctx, &sess, &uuid,
                               TEEC_LOGIN_PUBLIC, NULL, NULL, &err_origin);
        if (res != TEEC_SUCCESS)
                errx(1, "TEEC_Opensession failed with code 0x%x origin 0x%x",
                        res, err_origin);

        /* Clear the TEEC_Operation struct */
        memset(&op, 0, sizeof(op));
		/*
         * Prepare the argument. 
         */
        op.paramTypes = TEEC_PARAM_TYPES(TEEC_VALUE_INPUT, TEEC_VALUE_OUTPUT,
                                         TEEC_VALUE_INOUT, TEEC_NONE);
        op.params[0].value.a = 10;
		op.params[2].value.a = 11;

        res = TEEC_InvokeCommand(&sess, CMD_TEST_VALUE, &op,
                                 &err_origin);
        if (res != TEEC_SUCCESS)
                errx(1, "TEEC_InvokeCommand failed with code 0x%x origin 0x%x",
                        res, err_origin);
     

        TEEC_CloseSession(&sess);

        TEEC_FinalizeContext(&ctx);

        return 0;
}

TA

如下实现一个简单的TA代码示例，它实现了不同的Params类型，处理CA数据

#include <tee_internal_api.h>
#include <tee_internal_api_extensions.h>

#include <hello_world_ta.h>


TEE_Result TA_CreateEntryPoint(void)
{
        DMSG("has been called");

        return TEE_SUCCESS;
}


void TA_DestroyEntryPoint(void)
{
        DMSG("has been called");
}

TEE_Result TA_OpenSessionEntryPoint(uint32_t param_types,
                TEE_Param __maybe_unused params[4],
                void __maybe_unused **sess_ctx)
{
        uint32_t exp_param_types = TEE_PARAM_TYPES(TEE_PARAM_TYPE_NONE,
                                                   TEE_PARAM_TYPE_NONE,
                                                   TEE_PARAM_TYPE_NONE,
                                                   TEE_PARAM_TYPE_NONE);

        DMSG("has been called");

        if (param_types != exp_param_types)
                return TEE_ERROR_BAD_PARAMETERS;

        (void)&params;
        (void)&sess_ctx;

        IMSG("Hello World!\n");

        return TEE_SUCCESS;
}

void TA_CloseSessionEntryPoint(void __maybe_unused *sess_ctx)
{
        (void)&sess_ctx; /* Unused parameter */
        IMSG("Goodbye!\n");
}

static TEE_Result test_value(uint32_t param_types,
        TEE_Param params[4])
{
        uint32_t exp_param_types = TEE_PARAM_TYPES(TEE_PARAM_TYPE_VALUE_INPUT,
                                                   TEE_PARAM_TYPE_VALUE_OUTPUT,
                                                   TEE_PARAM_TYPE_INOUT,
                                                   TEE_PARAM_TYPE_NONE);
	    uint32_t value = 0;
        DMSG("has been called");

        if (param_types != exp_param_types)
                return TEE_ERROR_BAD_PARAMETERS;

        IMSG("Got value: %u from CA", params[0].value.a);
     	value = params[0].value.a;
     	value += 100;
        IMSG("increase value to: %u",value);
        params[1].value.a = value;
        IMSG("return increase data to normal world by params[1]");
        params[2].value.a = 12;
        IMSG("change data to normal world by params[2]");

        return TEE_SUCCESS;
}

TEE_Result TA_InvokeCommandEntryPoint(void __maybe_unused *sess_ctx,
                        uint32_t cmd_id,
                        uint32_t param_types, TEE_Param params[4])
{
        (void)&sess_ctx; /* Unused parameter */

        switch (cmd_id) {
      	  case CMD_TEST_VALUE:
      	  	test_value(param_types, params);
        
        default:
                return TEE_ERROR_BAD_PARAMETERS;
        }
}

本文 实现了一个使用3种 值传递 的params方式

• TEEC_VALUE_INPUT 只能ca向ta传递数据
• TEEC_VALUE_OUTPUT 只能ta向ca传递数据
• TEEC_VALUE_INOUT 双向传递数据