--- c-user/config/idle-task.rst | 95 ++++++++++++++++++++++++++++-- c-user/config/task-stack-alloc.rst | 39 ++++++++++-- 2 files changed, 124 insertions(+), 10 deletions(-)
diff --git a/c-user/config/idle-task.rst b/c-user/config/idle-task.rst index 359f862..d7b43ae 100644 --- a/c-user/config/idle-task.rst +++ b/c-user/config/idle-task.rst @@ -1,6 +1,6 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -.. Copyright (C) 2020, 2021 embedded brains GmbH (http://www.embedded-brains.de) +.. Copyright (C) 2020, 2022 embedded brains GmbH (http://www.embedded-brains.de) .. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR) .. This file is part of the RTEMS quality process and was automatically @@ -134,6 +134,74 @@ options otherwise a compile time error in the configuration file will occur. +.. Generated from spec:/acfg/if/idle-task-min-stack-size + +.. raw:: latex + + \clearpage + +.. index:: CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE +.. index:: minimum task stack size + +.. _CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE: + +CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE +-------------------------------------- + +.. rubric:: CONSTANT: + +``CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE`` + +.. rubric:: OPTION TYPE: + +This configuration option is an integer define. + +.. rubric:: DEFAULT VALUE: + +:c:macro:`CPU_STACK_MINIMUM_SIZE` / 4 + +.. rubric:: DESCRIPTION: + +The value of this configuration option defines the minimum stack size in +bytes for every :term:`IDLE task` in the system. + +.. rubric:: NOTES: + +Adjusting this parameter should be done with caution. Examining the actual +stack usage using the stack checker usage reporting facility is recommended +(see also :ref:`CONFIGURE_STACK_CHECKER_ENABLED`). + +This parameter can be used to increase the minimum from that +recommended. This can be used in higher memory systems to reduce the risk +of stack overflow without performing analysis on actual consumption. + +By default, the IDLE task storage areas are statically allocated. The size +of the task storage area is defined by the :ref:`CONFIGURE_IDLE_TASK_STACK_SIZE` +configuration option. The task storage area contains the task stack, the +thread-local storage, and the floating-point context on architectures with a +separate floating-point context. The size of the thread-local storage area +is defined at link time or by the :ref:`CONFIGURE_MAXIMUM_THREAD_LOCAL_STORAGE_SIZE` +configuration option. This configuration option is used to ensure that the +IDLE task stack size has at least the configured minimum size. If the IDLE +task stack size is too small, for example because the thread-local storage +size is too large, then the system terminates with the +:ref:`INTERNAL_ERROR_CORE <FatalErrorSources>` fatal source and the +:ref:`INTERNAL_ERROR_IDLE_THREAD_STACK_TOO_SMALL <internal_errors>` fatal code during +system initialization. + +.. rubric:: CONSTRAINTS: + +The value of the configuration option shall be large enough so that + +* the thread handler can call the thread switch extensions for the IDLE task, + +* the thread handler can call the thread begin extensions for the IDLE task, + +* the thread handler can call the IDLE task body (see + :ref:`CONFIGURE_IDLE_TASK_BODY`), and + +* the IDLE task can be interrupted by interrupt services. + .. Generated from spec:/acfg/if/idle-task-stack-size .. raw:: latex @@ -165,13 +233,30 @@ defined by the :ref:`CONFIGURE_MINIMUM_TASK_STACK_SIZE` configuration option. .. rubric:: DESCRIPTION: -The value of this configuration option defines the task stack size for an -IDLE task. +The value of this configuration option defines the task storage area size for +an IDLE task. .. rubric:: NOTES: -In SMP configurations, there is one IDLE task per configured processor, see -:ref:`CONFIGURE_MAXIMUM_PROCESSORS`. +Where the system was built with SMP support enabled, there is one IDLE task +for each configured processor, see :ref:`CONFIGURE_MAXIMUM_PROCESSORS`. + +By default, the IDLE task storage areas are statically allocated. The size +of the task storage area for each IDLE task is defined by this configuration +option. The task storage area contains the task stack, the thread-local +storage, and the floating-point context on architectures with a separate +floating-point context. The size of the thread-local storage area is defined +at link time or by the :ref:`CONFIGURE_MAXIMUM_THREAD_LOCAL_STORAGE_SIZE` configuration +option. The :ref:`CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE` configuration option is used +to ensure that the IDLE task stack size has at least the configured minimum +size. If the IDLE task stack size is too small, for example because the +thread-local storage size is too large, then the system terminates with the +:ref:`INTERNAL_ERROR_CORE <FatalErrorSources>` fatal source and the +:ref:`INTERNAL_ERROR_IDLE_THREAD_STACK_TOO_SMALL <internal_errors>` fatal code during +system initialization. + +You can use the :ref:`CONFIGURE_TASK_STACK_ALLOCATOR_FOR_IDLE` configuration option +to change the task stack allocator for IDLE tasks. .. rubric:: CONSTRAINTS: diff --git a/c-user/config/task-stack-alloc.rst b/c-user/config/task-stack-alloc.rst index 187bff5..b23edce 100644 --- a/c-user/config/task-stack-alloc.rst +++ b/c-user/config/task-stack-alloc.rst @@ -1,6 +1,6 @@ .. SPDX-License-Identifier: CC-BY-SA-4.0 -.. Copyright (C) 2020, 2021 embedded brains GmbH (http://www.embedded-brains.de) +.. Copyright (C) 2020, 2022 embedded brains GmbH (http://www.embedded-brains.de) .. Copyright (C) 1988, 2021 On-Line Applications Research Corporation (OAR) .. This file is part of the RTEMS quality process and was automatically @@ -136,8 +136,7 @@ This configuration option is an initializer define. .. rubric:: DEFAULT VALUE: -The default value is ``_Stack_Allocator_allocate_for_idle_default``, which -indicates that IDLE task stacks will be allocated from an area statically +By default, the IDLE task stacks will be allocated from an area statically allocated by ``<rtems/confdefs.h>``. .. rubric:: DESCRIPTION: @@ -153,10 +152,40 @@ configuration options. It is assumed that any memory allocated for the stack of an :term:`IDLE task` will not be from the RTEMS Workspace or the memory statically allocated by default. +The IDLE task stack allocator may increase the size of the allocated memory +area to account for the actual thread-local storage size which is defined at +link time. + +The size of the statically allocated memory area used by the default +allocator is defined by the :ref:`CONFIGURE_IDLE_TASK_STACK_SIZE` configuration +option. The :ref:`CONFIGURE_IDLE_TASK_MINIMUM_STACK_SIZE` configuration option ensures +that the IDLE task stack size has at least the configured minimum size. + +For applications with a thread-local storage size which is completely unknown +at the time the application configuration is defined, RTEMS provides an IDLE +task stack allocator which uses :c:func:`rtems_malloc`. The size +of the allocated thread storage area is the sum of stack size defined by the +:ref:`CONFIGURE_IDLE_TASK_STACK_SIZE` configuration option and the actual +thread-local storage size of the application. If the memory allocation +fails, then the system terminates with the +:ref:`INTERNAL_ERROR_CORE <FatalErrorSources>` fatal source and the +:ref:`INTERNAL_ERROR_NO_MEMORY_FOR_IDLE_TASK_STACK <internal_errors>` fatal code during +system initialization. Define this configuration option to +``rtems_malloc_task_stack_for_idle`` to use this allocator. + .. rubric:: CONSTRAINTS: -The value of the configuration option shall be defined to a valid function -pointer of the type ``void *( *allocate )( uint32_t, size_t )``. +The following constraints apply to this configuration option: + +* The value of the configuration option shall be defined to a valid function + pointer of the type ``void *( *allocate )( uint32_t, size_t * )``. + +* The IDLE task stack allocator shall return a pointer to the allocated memory + area or terminate the system with a fatal error if the allocation request + cannot be satisfied. + +* The IDLE task stack allocator may increase the size of the allocated memory + area. .. Generated from spec:/acfg/if/task-stack-allocator-init -- 2.35.3 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
