esp32: Workaround native code execution crash on ESP32-S2.

Seemingly ESP-IDF incorrectly marks RTC FAST memory region
as MALLOC_CAP_EXEC on ESP32-S2 when it isn't. This memory is
the lowest priority, so it only is returned if D/IRAM is exhausted.

Apply this workaround to treat the allocation as failed if it gives us
non-executable RAM back, rather than crashing.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <[email protected]>

Author: projectgus

ports/esp32/main.c

@@ -39,6 +39,7 @@
 #include "esp_task.h"
 #include "esp_event.h"
 #include "esp_log.h"
+#include "esp_memory_utils.h"
 #include "esp_psram.h"
 
 #include "py/cstack.h"
@@ -237,6 +238,13 @@ void *esp_native_code_commit(void *buf, size_t len, void *reloc) {
     len = (len + 3) & ~3;
     size_t len_node = sizeof(native_code_node_t) + len;
     native_code_node_t *node = heap_caps_malloc(len_node, MALLOC_CAP_EXEC);
+    #if CONFIG_IDF_TARGET_ESP32S2
+    // Workaround for ESP-IDF bug https://github.com/espressif/esp-idf/issues/14835
+    if (node != NULL && !esp_ptr_executable(node)) {
+        free(node);
+        node = NULL;
+    }
+    #endif // CONFIG_IDF_TARGET_ESP32S2
     if (node == NULL) {
         m_malloc_fail(len_node);
     }