Fixes to the Pi Pico build

* Don't require FreeRTOS if we are doing a bare metal bench / test build
* Make stack checking stricter and increase stack size for DH
* Set alignment to 0, this fixes LMS if that is compiled-in
* `WOLFSSL_SP_MATH` and `WOLFSSL_SP_MATH_ALL` can't be used together
* Loop the benchmark

Author: LinuxJedi

RPi-Pico/CMakeLists.txt

@@ -1,9 +1,13 @@
 cmake_minimum_required(VERSION 3.13)
 
-# Pull in Pico and FreeRTOS
+# Pull in Pico SDK
 include($ENV{PICO_SDK_PATH}/external/pico_sdk_import.cmake)
 #include(pico_extras_import_optional.cmake)
-include($ENV{FREERTOS_KERNEL_PATH}/portable/ThirdParty/GCC/RP2040/FreeRTOS_Kernel_import.cmake)
+
+# Pull in FreeRTOS if available (required for WiFi/TCP/TLS examples)
+if (DEFINED ENV{FREERTOS_KERNEL_PATH})
+    include($ENV{FREERTOS_KERNEL_PATH}/portable/ThirdParty/GCC/RP2040/FreeRTOS_Kernel_import.cmake)
+endif()
 
 
 if(PICO_SDK_VERSION_STRING VERSION_LESS "1.3.0")
@@ -27,6 +31,10 @@ if (USE_WIFI AND NOT PICO_CYW43_SUPPORTED)
     message(FATAL_ERROR "You can only set USE_WIFI when a PICO_BOARD with wifi is used")
 endif()
 
+if (USE_WIFI AND NOT DEFINED ENV{FREERTOS_KERNEL_PATH})
+    message(FATAL_ERROR "FREERTOS_KERNEL_PATH environment variable must be set when USE_WIFI is enabled")
+endif()
+
 ### Global Include Path
     include_directories(config)
     include_directories(include)
@@ -38,9 +46,11 @@ endif()
     #include_directories(${PICO_SDK_PATH}/lib/btstack/test/embedded/)
 
     set(WOLFSSL_ROOT $ENV{WOLFSSL_ROOT})
-    set(FREERTOS_KERNEL_PATH $ENV{FREERTOS_KERNEL_PATH})
-    include_directories(${FREERTOS_KERNEL_PATH}/include/)
-    include_directories(${FREERTOS_KERNEL_PATH}/portable/ThirdParty/GCC/RP2040/include)
+    if (DEFINED ENV{FREERTOS_KERNEL_PATH})
+        set(FREERTOS_KERNEL_PATH $ENV{FREERTOS_KERNEL_PATH})
+        include_directories(${FREERTOS_KERNEL_PATH}/include/)
+        include_directories(${FREERTOS_KERNEL_PATH}/portable/ThirdParty/GCC/RP2040/include)
+    endif()
     include_directories(${WOLFSSL_ROOT})
 ### End of Global Include Path
 

RPi-Pico/benchmark/CMakeLists.txt

@@ -11,6 +11,7 @@ target_link_libraries(benchmark
 
 target_compile_definitions(benchmark PRIVATE
     WOLFSSL_RPI_PICO
+    PICO_STACK_SIZE=4096
 )
 
 if (USE_UART)

RPi-Pico/config/user_settings.h

@@ -45,7 +45,7 @@ extern time_t myTime(time_t *);
 /* ------------------------------------------------------------------------- */
 /* Platform */
 /* ------------------------------------------------------------------------- */
-#define WOLFSSL_GENERAL_ALIGNMENT 4
+#define WOLFSSL_GENERAL_ALIGNMENT 0
 #define SIZEOF_LONG_LONG 8
 #if 0
 #define NO_64BIT /* disable use of 64-bit variables */
@@ -76,7 +76,7 @@ extern time_t myTime(time_t *);
 // #define WOLFSSL_SP_384 /* Enable ECC 384-bit SECP384R1 support */
 
 // #define WOLFSSL_SP_CACHE_RESISTANT
-#define WOLFSSL_SP_MATH     /* only SP math - disables integer.c/tfm.c */
+//#define WOLFSSL_SP_MATH     /* only SP math - disables integer.c/tfm.c */
 #define WOLFSSL_SP_MATH_ALL /* use SP math for all key sizes and curves */
 
     // #define WOLFSSL_SP_NO_MALLOC

RPi-Pico/src/bench_main.c

@@ -37,9 +37,11 @@ int main(int argc, char **argv)
     int ret;
 
     stdio_init_all();
-    printf("\nSystem clock = %dMHz\n\n", clock_get_hz(clk_sys)/1000000);
-    ret = benchmark_test(NULL);
-    printf("End: %d\n", ret);
+    while(1) {
+        printf("\nSystem clock = %dMHz\n\n", clock_get_hz(clk_sys)/1000000);
+        ret = benchmark_test(NULL);
+        printf("End: %d\n", ret);
+    }
     return ret;
 }
 

RPi-Pico/wolfssl_import.cmake

@@ -31,6 +31,8 @@ target_compile_definitions(wolfssl PUBLIC
     WOLFSSL_USER_SETTINGS
 )
 
+add_compile_definitions(PICO_USE_STACK_GUARDS=1)
+
 if (${PICO_PLATFORM} STREQUAL "rp2350-arm-s")
 add_compile_definitions(wolfssl WOLFSSL_SP_ARM_CORTEX_M_ASM)
 elseif (${PICO_PLATFORM} STREQUAL "rp2350-riscv")