feat(pthread): Pthread can now use PSRAM as stack

Closes https://github.com/espressif/esp-idf/pull/10623
Closes https://github.com/espressif/esp-idf/issues/8662

Thanks to f-hoepfinger-hr-agrartechnik for the contribution
in https://github.com/espressif/esp-idf/pull/10623

docs/en/api-reference/system/mem_alloc.rst

@@ -14,6 +14,8 @@ Because {IDF_TARGET_NAME} uses multiple types of RAM, it also contains multiple
 
 For most purposes, the C Standard Library's ``malloc()`` and ``free()`` functions can be used for heap allocation without any special consideration. However, in order to fully make use of all of the memory types and their characteristics, ESP-IDF also has a capabilities-based heap memory allocator. If you want to have a memory with certain properties (e.g., :ref:`dma-capable-memory` or executable-memory), you can create an OR-mask of the required capabilities and pass that to :cpp:func:`heap_caps_malloc`.
 
+.. _memory_capabilities:
+
 Memory Capabilities
 -------------------
 

docs/en/api-reference/system/pthread.rst

@@ -188,6 +188,7 @@ The API :cpp:func:`esp_pthread_set_cfg` defined in the ``esp_pthreads.h`` header
 
 .. list::
     - Default stack size of new threads, if not specified when calling ``pthread_create()`` (overrides :ref:`CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT`).
+    - Stack memory capabilities: They determine which kind of memory is used for allocating pthread stacks. The field takes ESP-IDF heap capability flags, as defined in :component_file:`heap/include/esp_heap_caps.h`. The memory must be 8-bit accessible (MALLOC_CAP_8BIT), besides other custom flags the user can choose from. The user is responsible for ensuring the correctness of the stack memory capabilities. For more information about memory locations, refer to the documentation of :ref:`Memory Capabilities <memory_capabilities>`
     - RTOS priority of new threads (overrides :ref:`CONFIG_PTHREAD_TASK_PRIO_DEFAULT`).
     :SOC_HP_CPU_HAS_MULTIPLE_CORES: - Core affinity / core pinning of new threads (overrides :ref:`CONFIG_PTHREAD_TASK_CORE_DEFAULT`).
     - FreeRTOS task name for new threads (overrides :ref:`CONFIG_PTHREAD_TASK_NAME_DEFAULT`)