Move num_ops ECP abstraction fully into internal implementation

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 2c6f108..39da74b 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3487,13 +3487,16 @@
 }
 
 uint32_t mbedtls_psa_sign_hash_get_num_ops(
-    const mbedtls_psa_sign_hash_interruptible_operation_t *operation)
+    mbedtls_psa_sign_hash_interruptible_operation_t *operation)
 {
 #if (defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)) && \
     defined(MBEDTLS_ECP_RESTARTABLE)
 
-    return operation->restart_ctx.ecp.ops_done;
+    /* Hide the fact that the restart context only holds a delta of number of
+     * ops done during the last operation, not an absolute value. */
+    operation->num_ops += operation->restart_ctx.ecp.ops_done;
+    return operation->num_ops;
 #else
     (void) operation;
     return 0;
@@ -3503,13 +3506,16 @@
 }
 
 uint32_t mbedtls_psa_verify_hash_get_num_ops(
-    const mbedtls_psa_verify_hash_interruptible_operation_t *operation)
+    mbedtls_psa_verify_hash_interruptible_operation_t *operation)
 {
     #if (defined(MBEDTLS_PSA_BUILTIN_ALG_ECDSA) || \
     defined(MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA)) && \
     defined(MBEDTLS_ECP_RESTARTABLE)
 
-    return operation->restart_ctx.ecp.ops_done;
+    /* Hide the fact that the restart context only holds a delta of number of
+     * ops done during the last operation, not an absolute value. */
+    operation->num_ops += operation->restart_ctx.ecp.ops_done;
+    return operation->num_ops;
 #else
     (void) operation;
     return 0;
@@ -3541,6 +3547,9 @@
 
     mbedtls_ecdsa_restart_init(&operation->restart_ctx);
 
+    /* Ensure num_ops is zero'ed in case of context re-use. */
+    operation->num_ops = 0;
+
     /* Ensure default is set even if
      * mbedtls_psa_interruptible_set_max_ops() has not been called. */
     mbedtls_psa_interruptible_set_max_ops(
@@ -3706,6 +3715,8 @@
 
     mbedtls_ecdsa_restart_free(&operation->restart_ctx);
 
+    operation->num_ops = 0;
+
     return PSA_SUCCESS;
 
 #else
@@ -3747,6 +3758,9 @@
     mbedtls_mpi_init(&operation->r);
     mbedtls_mpi_init(&operation->s);
 
+    /* Ensure num_ops is zero'ed in case of context re-use. */
+    operation->num_ops = 0;
+
     /* Ensure default is set even if
      * mbedtls_psa_interruptible_set_max_ops() has not been called. */
     mbedtls_psa_interruptible_set_max_ops(
@@ -3864,6 +3878,8 @@
 
     mbedtls_ecdsa_restart_free(&operation->restart_ctx);
 
+    operation->num_ops = 0;
+
     mbedtls_mpi_free(&operation->r);
     mbedtls_mpi_free(&operation->s);
 
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index 5648321..0ef0131 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -643,12 +643,11 @@
  *        zero.
  *
  * \note The signature of this function is that of a PSA driver
- *       sign_get_num_ops entry point, however it differs in behaviour from the
- *       driver function in that this function returns a delta of work done in
- *       the last call rather than all of the ops done ever by the whole
- *       operation, due to internal implementation differences.
+ *       sign_hash_get_num_ops entry point. This function behaves as an
+ *       sign_hash_get_num_ops entry point as defined in the PSA driver
+ *       interface specification for transparent drivers.
  *
- * \param[in]  operation        The \c
+ * \param   operation           The \c
  *                              mbedtls_psa_sign_hash_interruptible_operation_t
  *                              to use. This must be initialized first.
  *
@@ -657,7 +656,7 @@
  *                              mbedtls_psa_sign_hash_complete().
  */
 uint32_t mbedtls_psa_sign_hash_get_num_ops(
-    const mbedtls_psa_sign_hash_interruptible_operation_t *operation);
+    mbedtls_psa_sign_hash_interruptible_operation_t *operation);
 
 /**
  * \brief Get the number of ops that a hash verification operation has taken for
@@ -665,12 +664,11 @@
  *        return zero.
  *
  * \note The signature of this function is that of a PSA driver
- *       verify_get_num_ops entry point however it differs in behaviour from the
- *       driver function in that this function returns a delta of work done in
- *       the last call rather than all of the ops done ever by the whole
- *       operation, due to internal implementation differences.
+ *       verify_hash_get_num_ops entry point. This function behaves as an
+ *       verify_hash_get_num_ops entry point as defined in the PSA driver
+ *       interface specification for transparent drivers.
  *
- * \param[in]  operation        The \c
+ * \param   operation           The \c
  *                              mbedtls_psa_verify_hash_interruptible_operation_t
  *                              to use. This must be initialized first.
  *
@@ -679,7 +677,7 @@
  *                              mbedtls_psa_verify_hash_complete().
  */
 uint32_t mbedtls_psa_verify_hash_get_num_ops(
-    const mbedtls_psa_verify_hash_interruptible_operation_t *operation);
+    mbedtls_psa_verify_hash_interruptible_operation_t *operation);
 
 /**
  * \brief  Start signing a hash or short message with a private key, in an
diff --git a/library/psa_crypto_driver_wrappers.h b/library/psa_crypto_driver_wrappers.h
index 26df088..e3edec7 100644
--- a/library/psa_crypto_driver_wrappers.h
+++ b/library/psa_crypto_driver_wrappers.h
@@ -75,10 +75,10 @@
 uint32_t psa_driver_wrapper_interruptible_get_max_ops(void);
 
 uint32_t psa_driver_wrapper_sign_hash_get_num_ops(
-    const psa_sign_hash_interruptible_operation_t *operation);
+    psa_sign_hash_interruptible_operation_t *operation);
 
 uint32_t psa_driver_wrapper_verify_hash_get_num_ops(
-    const psa_verify_hash_interruptible_operation_t *operation);
+    psa_verify_hash_interruptible_operation_t *operation);
 
 psa_status_t psa_driver_wrapper_sign_hash_start(
     psa_sign_hash_interruptible_operation_t *operation,