Merge pull request #7099 from RonEld/platform_context_reference_count

Add reference counter for platform context

features/cryptocell/FEATURE_CRYPTOCELL310/Readme.md

@@ -16,6 +16,6 @@ To port your CC 310 driver to Mbed OS on your specific target, do the following:
 1. In `objects.h`, include `objects_cryptocell.h`. You can use the `FEATURE_CRYPTOCELL310` precompilation check as defined above.
 1. In `features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_<target name>`, add your platform-specific libraries for all toolchains in `TOOLCHAIN_ARM`, `TOOLCHAIN_GCC_ARM` and `TOOLCHAIN_IAR` respectively.
 1. Add your CC setup code:
- * Implement `cc_platform_setup()` and `cc_platform_terminate()` to enable CC on your platform, in case you have board-specific setup functionality, required for CC setup. These functions can be empty.
- * Define `cc_platform_ctx` in `cc_platform.h` in a way that suits your implementation.
+ * Implement `crypto_platform_setup()` and `crypto_platform_terminate()` to enable CC on your platform, in case you have board-specific setup functionality, required for CC setup. You MUST call 'SaSi_LibInit()` and 'SaSi_LibFini()' respectively in these functions.
+ * Define `crypto_platform_ctx` in `crypto_platform.h` in a way that suits your implementation.
 

features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/cc_platform_nrf52840.c → features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/crypto_platform.c

@@ -1,5 +1,5 @@
  /*
- * cc_platform_nrf52840.c
+ * crypto_platform.c
  *
  * Copyright (C) 2018, Arm Limited, All Rights Reserved
  * SPDX-License-Identifier: Apache-2.0
@@ -20,14 +20,25 @@
 
 #include "platform_alt.h"
 #include "nrf52840.h"
+#include "sns_silib.h"
+#if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
 
-int cc_platform_setup( cc_platform_ctx *ctx )
+static CRYS_RND_WorkBuff_t rndWorkBuff = { { 0 } } ;
+
+int crypto_platform_setup( crypto_platform_ctx *ctx )
 {
  NRF_CRYPTOCELL->ENABLE = 1;
+
+ if( SaSi_LibInit( &ctx->rndState, &rndWorkBuff ) != 0 )
+ return ( MBEDTLS_ERR_PLATFORM_HW_FAILED );
+
  return ( 0 );
 }
 
-void cc_platform_terminate( cc_platform_ctx *ctx )
+void crypto_platform_terminate( crypto_platform_ctx *ctx )
 {
+ SaSi_LibFini( &ctx->rndState );
  NRF_CRYPTOCELL->ENABLE = 0;
 }
+
+#endif /* MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT */

features/cryptocell/FEATURE_CRYPTOCELL310/TARGET_MCU_NRF52840/cc_platform.h → 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
@@ -17,17 +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. */
+  CRYS_RND_State_t rndState;
 }
-cc_platform_ctx;
-
-#endif /* __CC_PLATFORM_H_ */
+crypto_platform_ctx;
+#endif /* MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT */
+#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 = { { 0 } };
 
 /* 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/cryptocell/FEATURE_CRYPTOCELL310/platform_alt.h → features/mbedtls/platform/inc/platform_alt.h

@@ -20,50 +20,47 @@
 
 #ifndef __PLATFORM_ALT__
 #define __PLATFORM_ALT__
-#include "cc_platform.h"
-#include "crys_rnd.h"
-
+#include "platform_mbed.h"
+#if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
+#include "crypto_platform.h"
 /**
  * \brief The platform context structure.
  *
  * \note This structure may be used to assist platform-specific
  * setup or teardown operations.
  */
 typedef struct {
- cc_platform_ctx platform_impl_ctx; /** A context holding all the partner's platform specific context */
- /*
- * Add CRYS_RND_State_t rndState; when https://github.com/ARMmbed/mbedtls/issues/1200 is supported
- * */
+ 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;
 
 
 /**
- * \brief This function performs any partner platform initialization operations,
- * needed top enable CryptoCell.
+ * \brief This function performs any platform initialization operations,
+ * needed for setting up cryptographic modules.
  *
  * \param ctx The platform specific context.
  *
  * \return \c 0 on success.
  *
- * \note This function is intended to allow platform-specific initialization for CryptoCell,
- * and is called before initializing the CC library(SaSi_LibInit). Its
+ * \note This function is intended to allow platform-specific initialization for Mbed TLS,
+ * and is called before initializing the Mbed TLS functions. Its
  * implementation is platform-specific, and its implementation MUST be provided.
  *
  */
-int cc_platform_setup( cc_platform_ctx *ctx );
+int crypto_platform_setup( crypto_platform_ctx *unused_ctx );
 
 /**
- * \brief This function performs any partner platform teardown operations, to disable CryptoCell.
+ * \brief This function performs any platform teardown operations, to disable cryptographic operations.
  *
  * \param ctx The platform specific context.
  *
- * \note This function is called after terminating CC library(SaSi_LibFini)
- * and intended to free any resource used for CryptoCell by the platform.
+ * \note This function is intended to free any resource used Mbed TLS by the platform.
  * Its implementation is platform-specific,and its implementation MUST be provided.
  *
  */
-void cc_platform_terminate( cc_platform_ctx *ctx );
-
+void crypto_platform_terminate( crypto_platform_ctx *unused_ctx );
+#endif
 #endif /* __PLATFORM_ALT__ */
 

features/mbedtls/platform/inc/platform_mbed.h

@@ -24,3 +24,5 @@
 #if defined(MBEDTLS_CONFIG_HW_SUPPORT)
 #include "mbedtls_device.h"
 #endif
+
+#define MBEDTLS_ERR_PLATFORM_HW_FAILED -0x0080

features/cryptocell/FEATURE_CRYPTOCELL310/platform_alt.c → features/mbedtls/platform/src/platform_alt.c

@@ -20,38 +20,33 @@
 
 #include "mbedtls/platform.h"
 #if defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
-#include "sns_silib.h"
+#include "mbed_critical.h"
 
-/* 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 */
+mbedtls_platform_context ctx = { { 0 } };
 
-CRYS_RND_State_t rndState = { { 0 } } ;
-CRYS_RND_WorkBuff_t rndWorkBuff = { { 0 } } ;
-
-
-int mbedtls_platform_setup( mbedtls_platform_context *ctx )
+int mbedtls_platform_setup( mbedtls_platform_context *unused_ctx )
 {
  int ret = 0;
- if( ctx == NULL )
- return ( -1 );
 
- /* call platform specific code to setup CC driver*/
- if( ( ret = cc_platform_setup( &ctx->platform_impl_ctx ) ) != 0 )
- return ( ret );
+ core_util_atomic_incr_u32( ( volatile uint32_t * )&ctx.reference_count, 1 );
 
- if( SaSi_LibInit( &rndState, &rndWorkBuff ) != 0 )
- return ( -1 );
- return ( 0 );
+ if( ctx.reference_count == 1 )
+ {
+ /* call platform specific code to setup crypto driver */
+ 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 *unused_ctx )
 {
- if( ctx == NULL )
- return;
-
- SaSi_LibFini( &rndState );
- cc_platform_terminate( &ctx->platform_impl_ctx );
+ core_util_atomic_decr_u32( ( volatile uint32_t * )&ctx.reference_count, 1 );
+ if( ctx.reference_count < 1 )
+ {
+ /* call platform specific code to terminate crypto driver */
+ crypto_platform_terminate( &ctx.platform_impl_ctx );
+ ctx.reference_count = 0;
+ }
 }
 
 #endif /* MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT*/