mbedtls: Add an alt implementation of timing

Implement the MBEDTLS_TIMING_ALT interface for Mbed OS. This
implementation is sufficient to run the Mbed TLS benchmarking
application.

connectivity/mbedtls/CMakeLists.txt

@@ -16,6 +16,7 @@ target_sources(mbed-mbedtls
  platform/src/mbed_trng.cpp
  platform/src/platform_alt.cpp
  platform/src/shared_rng.cpp
+ platform/src/timing.cpp
 
  source/aes.c
  source/aesni.c

connectivity/mbedtls/include/mbedtls/check_config.h

@@ -55,9 +55,8 @@
 #endif
 #endif /* _WIN32 */
 
-#if defined(TARGET_LIKE_MBED) && \
- ( defined(MBEDTLS_NET_C) || defined(MBEDTLS_TIMING_C) )
-#error "The NET and TIMING modules are not available for mbed OS - please use the network and timing functions provided by mbed OS"
+#if defined(TARGET_LIKE_MBED) && defined(MBEDTLS_NET_C)
+#error "The NET module is not available for mbed OS - please use the network functions provided by mbed OS"
 #endif
 
 #if defined(MBEDTLS_DEPRECATED_WARNING) && \

connectivity/mbedtls/platform/inc/timing_alt.h

@@ -0,0 +1,42 @@
+/*
+ * timing_alt.h
+ *
+ * Copyright (C) 2021, Arm Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef TIMING_ALT_H
+#define TIMING_ALT_H
+
+#include "mbedtls/timing.h"
+#if defined(MBEDTLS_TIMING_ALT)
+
+#include <time.h>
+
+struct mbedtls_timing_hr_time
+{
+ struct timeval start;
+};
+
+typedef struct mbedtls_timing_delay_context
+{
+ struct mbedtls_timing_hr_time timer;
+ uint32_t int_ms;
+ uint32_t fin_ms;
+} mbedtls_timing_delay_context;
+
+#endif
+#endif

connectivity/mbedtls/platform/src/timing.cpp

@@ -0,0 +1,67 @@
+/*
+ * timing.cpp
+ *
+ * Copyright (C) 2021, Arm Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+#include "mbedtls/timing.h"
+#include "drivers/Timeout.h"
+#include <chrono>
+
+extern "C" {
+ volatile int mbedtls_timing_alarmed = 0;
+};
+
+static void handle_alarm(void)
+{
+ mbedtls_timing_alarmed = 1;
+}
+
+extern "C" void mbedtls_set_alarm(int seconds)
+{
+ static mbed::Timeout t;
+ mbedtls_timing_alarmed = 0;
+
+ t.attach(handle_alarm, std::chrono::seconds(seconds));
+}
+
+#if !defined(HAVE_HARDCLOCK)
+#define HAVE_HARDCLOCK
+#include "platform/mbed_rtc_time.h"
+static int hardclock_init = 0;
+static struct timeval tv_init;
+
+extern "C" unsigned long mbedtls_timing_hardclock(void)
+{
+ struct timeval tv_cur;
+
+ if (hardclock_init == 0)
+ {
+ gettimeofday(&tv_init, NULL);
+ hardclock_init = 1;
+ }
+
+ gettimeofday(&tv_cur, NULL);
+ return((tv_cur.tv_sec - tv_init.tv_sec) * 1000000
+ + (tv_cur.tv_usec - tv_init.tv_usec));
+}
+#endif /* !HAVE_HARDCLOCK */