heap: add check for usage of flash content from iram

this commits:
- adds build-time test to check that no call to flash regions are done from IRAM functions

- resolves problems related to IRAM function using content in flash memory

- update heap_caps_alloc_failed to use a default function name in DRAM
  when necessary instead of creating a function name variable in DRAM for
  each call of heap_caps_alloc_failed. This allows to save some extra bytes
  in RAM.

components/heap/CMakeLists.txt

@@ -37,7 +37,7 @@ idf_component_register(SRCS "${srcs}"
                     INCLUDE_DIRS ${includes}
                     PRIV_INCLUDE_DIRS ${priv_includes}
                     LDFRAGMENTS linker.lf
-                    PRIV_REQUIRES soc)
+                    PRIV_REQUIRES soc spi_flash)
 
 if(CONFIG_HEAP_TRACING)
     set(WRAP_FUNCTIONS

components/heap/heap_caps.c

@@ -14,7 +14,7 @@
 #include "esp_log.h"
 #include "heap_private.h"
 #include "esp_system.h"
-
+#include "esp_private/cache_utils.h"
 
 /* Forward declaration for base function, put in IRAM.
  * These functions don't check for errors after trying to allocate memory. */
@@ -56,10 +56,16 @@ IRAM_ATTR static void *dram_alloc_to_iram_addr(void *addr, size_t len)
 }
 
 
-static void heap_caps_alloc_failed(size_t requested_size, uint32_t caps, const char *function_name)
+IRAM_ATTR static void heap_caps_alloc_failed(size_t requested_size, uint32_t caps, const char *function_name)
 {
+    static const DRAM_ATTR char *default_func_name = "<function_name>";
     if (alloc_failed_callback) {
-        alloc_failed_callback(requested_size, caps, function_name);
+        if (!spi_flash_cache_enabled() && !esp_ptr_internal(function_name)) {
+            alloc_failed_callback(requested_size, caps, default_func_name);
+        }
+        else {
+            alloc_failed_callback(requested_size, caps, function_name);
+        }
     }
 
 #ifdef CONFIG_HEAP_ABORT_WHEN_ALLOCATION_FAILS

components/heap/test_apps/CMakeLists.txt

@@ -4,3 +4,16 @@ cmake_minimum_required(VERSION 3.16)
 
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 project(test_heap)
+
+if(CONFIG_COMPILER_DUMP_RTL_FILES)
+    add_custom_target(check_test_app_sections ALL
+                      COMMAND ${PYTHON} $ENV{IDF_PATH}/tools/ci/check_callgraph.py
+                      --rtl-dir ${CMAKE_BINARY_DIR}/esp-idf/heap/
+                      --elf-file ${CMAKE_BINARY_DIR}/test_heap.elf
+                      find-refs
+                      --from-sections=.iram0.text
+                      --to-sections=.flash.text,.flash.rodata
+                      --exit-code
+                      DEPENDS ${elf}
+                      )
+endif()

components/heap/test_apps/sdkconfig.defaults

@@ -1,2 +1,3 @@
+CONFIG_COMPILER_DUMP_RTL_FILES=y
 CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU0=n
 CONFIG_ESP_SYSTEM_MEMPROT_FEATURE=n # memory protection needs to be disabled for certain tests