Make the platform context a global variable

Make the platform context a global variable,
adding the refernce counter to it.

Author: Ron Eldor

features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/crypto_platform.c

@@ -22,26 +22,22 @@
 #include "nrf52840.h"
 #include "sns_silib.h"
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
-/* once https://github.com/ARMmbed/mbedtls/issues/1200 will be supported,
- * rndState should be part of mbedtls_platform_context
- * Until then, we should keep it global and extern */
 
-CRYS_RND_State_t     rndState = { { 0 } } ;
-CRYS_RND_WorkBuff_t  rndWorkBuff = { { 0 } } ;
+static CRYS_RND_WorkBuff_t  rndWorkBuff = { { 0 } } ;
 
 int crypto_platform_setup( crypto_platform_ctx *ctx )
 {
     NRF_CRYPTOCELL->ENABLE = 1;
 
-    if( SaSi_LibInit( &rndState, &rndWorkBuff ) != 0 )
+    if( SaSi_LibInit( &ctx->rndState, &rndWorkBuff ) != 0 )
           return ( MBEDTLS_PLATFORM_HW_FAILED );
 
     return ( 0 );
 }
 
 void crypto_platform_terminate( crypto_platform_ctx *ctx )
 {
-    SaSi_LibFini( &rndState );
+    SaSi_LibFini( &ctx->rndState );
     NRF_CRYPTOCELL->ENABLE = 0;
 }
 

features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/crypto_platform.h

@@ -1,5 +1,5 @@
 /*
-  *  cc_platform.h
+  *  crypto_platform.h
   *
   *  Copyright (C) 2018, Arm Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
@@ -17,21 +17,19 @@
   *  limitations under the License.
   *
   */
-#ifndef __CC_PLATFORM_H_
-#define __CC_PLATFORM_H_
+#ifndef __CRYPTO_PLATFORM_H_
+#define __CRYPTO_PLATFORM_H_
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
+#include "crys_rnd.h"
 /**
  * \brief   The CC platform context structure.
  *
  * \note    This structure may be used to assist platform-specific
  *          setup or teardown operations.
  */
 typedef struct {
-    char dummy; /**< Placeholder member, as empty structs are not portable. */
-    /*
-     * Add CRYS_RND_State_t rndState; when https://github.com/ARMmbed/mbedtls/issues/1200 is supported
-     */
+     CRYS_RND_State_t rndState;
 }
 crypto_platform_ctx;
 #endif /* MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT */
-#endif /* __CC_PLATFORM_H_ */
+#endif /* __CRYPTO_PLATFORM_H_ */

features/cryptocell/FEATURE_CRYPTOCELL310/trng.c

@@ -22,9 +22,10 @@
 
 #include <string.h>
 #include "trng_api.h"
+#include "mbedtls/platform.h"
 
-extern CRYS_RND_State_t     rndState;
-extern CRYS_RND_WorkBuff_t  rndWorkBuff;
+extern mbedtls_platform_context  ctx;
+static CRYS_RND_WorkBuff_t  rndWorkBuff;
 
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
@@ -48,7 +49,7 @@ CRYSError_t LLF_RND_GetTrngSource(
 
 void trng_init(trng_t *obj)
 {
-    RNG_PLAT_SetUserRngParameters(&rndState, obj);
+    RNG_PLAT_SetUserRngParameters(&ctx.platform_impl_ctx.rndState, obj);
 }
 
 void trng_free(trng_t *obj)
@@ -66,7 +67,7 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *outputLe
     uint32_t actualLength;
 
     ret = LLF_RND_GetTrngSource(
-                &rndState ,    /*in/out*/
+                &ctx.platform_impl_ctx.rndState ,    /*in/out*/
                 obj,       /*in/out*/
                 0,       /*in*/
                 &entropySizeBits,  /*in/out*/

features/mbedtls/platform/inc/platform_alt.h

@@ -23,7 +23,6 @@
 #include "platform_mbed.h"
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
 #include "crypto_platform.h"
-
 /**
  * \brief   The platform context structure.
  *
@@ -32,6 +31,7 @@
  */
 typedef struct {
     crypto_platform_ctx platform_impl_ctx; /* A context holding all the platform specific context for cryptography. Should be defined in crypto_platform.h */
+    int reference_count;
 }
 mbedtls_platform_context;
 

features/mbedtls/platform/src/platform_alt.c

@@ -20,37 +20,32 @@
 
 #include "mbedtls/platform.h"
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
+mbedtls_platform_context ctx = {0};
 
-static int reference_count = 0;
-
-int mbedtls_platform_setup( mbedtls_platform_context *ctx )
+int mbedtls_platform_setup( mbedtls_platform_context *obsolete_ctx )
 {
     int ret = 0;
-    if( ctx == NULL )
-        return ( MBEDTLS_PLATFORM_INVALID_DATA );
 
-    reference_count++;
+    ctx.reference_count++;
 
-    if( reference_count == 1 )
+    if( ctx.reference_count == 1 )
     {
         /* call platform specific code to setup crypto driver*/
-        ret = crypto_platform_setup( &ctx->platform_impl_ctx );
+        ret = crypto_platform_setup( &ctx.platform_impl_ctx );
     }
     return ( ret );
 }
 
-void mbedtls_platform_teardown( mbedtls_platform_context *ctx )
+void mbedtls_platform_teardown( mbedtls_platform_context *obsolete_ctx )
 {
-    if( ctx == NULL )
-        return;
 
-    reference_count--;
+    ctx.reference_count--;
 
-    if( reference_count <= 0 )
+    if( ctx.reference_count <= 0 )
     {
         /* call platform specific code to terminate crypto driver*/
-        crypto_platform_terminate( &ctx->platform_impl_ctx );
-        reference_count = 0;
+        crypto_platform_terminate( &ctx.platform_impl_ctx );
+        ctx.reference_count = 0;
     }
 }