This commit refactors the FPU handling code on the Xtensa port of Amazon SMP
FreeRTOS in the following ways:
Auto-pinning via XT_RTOS_CP_EXC_HOOK
------------------------------------
The "_xt_coproc_exc" exception would previously automatically pin a task that
uses the FPU to the current core (to ensure that we can lazy save the task's FPU
context). However, this would mean that "xtensa_vectors.S" would need to be
OS-aware (to read the task's TCB structure).
This is now refactored so that "_xt_coproc_exc" calls a CP exception hook
function ("XT_RTOS_CP_EXC_HOOK") implemented in "portasm.S", thus allowing
"xtensa_vectors.S" to remain OS agnostic.
Using macros to acquire owner spinlock
--------------------------------------
The taking and relasing of the "_xt_coproc_owner_sa_lock" is now mostly
abstracted as the "spinlock_take" and "spinlock_release" macro. As a result,
"_xt_coproc_release" and "_xt_coproc_exc" are refactored so that:
- They are closer to their upstream (original) versions
- The spinlock is only taken when building for multicore
- The spinlock held region is shortened (now only protects the instructions
that access the "_xt_coproc_owner_sa" array
Other Changes
-------------
- Updated placing and comments of various "offset_..." constants used by
portasm.S
- Update description of "get_cpsa_from_tcb" assembly macro
- Tidied up some typos in the ".S" files
This commit fixes the following FPU/Coprocessor bugs in the Xtensa port of
Amazon SMP FreeRTOS:
- vPortCleanUpCoprocArea() does not calculate the correct pointer to the
task's CPSA (located on the task's stack). This can result in
- _xt_coproc_release() not releasing the task's CP ownership
- The next coprocessor exception will write the current CP owner (i.e., the
deleted task's CPSA) leading to memory corruption
- _xt_coproc_release() writes xCoreID instead of 0 when clearing a CP owner.
This results in the next CP exception trying to load the CP owner's CPSA at
the address of "xCoreID", leading to a double exception.
This commit refactors port_common.c so that it only contains implementation of
FreeRTOS port functions that are common to all FreeRTOS ports (i.e., on all
architectures and on all FreeRTOS implementations).
This commit refactors the OS startup functions as follows:
- Moved the OS/app startup functions listed below to "app_startup.c". Their
implementations are now common to all ports (RISC-V and Xtensa) of all
FreeRTOS implementations (IDF and Amazon SMP).
- esp_startup_start_app()
- esp_startup_start_app_other_cores()
- Removed esp_startup_start_app_common() as app startup functions are now
already common to all ports.
- Added extra logs to "main_task" to help with user debugging
Note: Increased startup delay on "unity_task". The "unity_run_menu()" is non
blocking, thus if the main task or other startup tasks have not been freed
by the time "unity_run_menu()" is run, those tasks will be freed the next time
"unity_task" blocks. This could cause some tests to have a memory leak, thus
the "unity_task" startup delay has increased.
The following changes have been made in this commit:
1. configMINIMAL_STACK_SIZE is now defined as CONFIG_FREERTOS_IDLE_TASK_STACKSIZE.
2. Removed configIDLE_TASK_STACK_SIZE config as it was redundant.
3. Updates the order of allocating the TCB and stack memory to avoid the
stack memory overriding the TCB memory when the stack grows downwards.
4. CONFIG_FREERTOS_IDLE_TASK_STACKSIZE is now incorporated into the
FreeRTOSConfig_smp.h to configure the IDLE0 stack size.
This commit refactors the pxPortInitialiseStack() function of the xtensa
FreeRTOS ports (both IDF and SMP FreeRTOS).
- Each stack area is now separated into their own functions
- Each function will individually
- Push the stack pointer to allocate the stack area
- Initiaze the allocated stack area
- Each stack area's size and usage is now clearly documented in code
ESP32-C2 has a single group timer, thus it will use it for the interrupt watchdog,
which is more critical than the task watchdog. The latter is implement in
software thanks to the `esp_timer`component.
This function removes the following legacy atomic CAS functions:
From compare_set.h (file removed):
- compare_and_set_native()
- compare_and_set_extram()
From portmacro.h
- uxPortCompareSet()
- uxPortCompareSetExtram()
Users should call esp_cpu_compare_and_set() instead as this function hides the details
of atomic CAS on internal and external RAM addresses.
Due to the removal of compare_set.h, some missing header includes are also fixed in this commit.
FreeRTOS uses a single "xSchedulerRunning" variable to tack whether the
scheduler has started, and this variable is set to "pdTRUE" by core 0
via calling vTaskStartScheduler().
However, with SMP FreeRTOS, there is a race condition where core 0 has
already started the scheduler and another core has not called xPortStartScheduler()
yet and calls some FreeRTOS API. Thus the resultant FreeRTOS API can
cause errors as it thinks the scheduler has started.
This commit adds a temporary workaround (by having each core maintain their
own "xSchedulerRunning" variable.
This commit fixes how SMP FreeRTOS feeds the INT WDT. Previously, the
port used vApplicationTickHook(). Now, all cores will feed the INT WDT
in xPortSysTickHandler().
This commit moidifies the TWDT as follows:
- Adds a feature to allows subscribing arbitrary users to the TWDT
- Changes esp_task_wdt_init() API to accept configuration structure
- Changes esp_task_wdt_init() and esp_task_wdt_deinit() to subscribe/unsubscribe
idle tasks of various cores.
- Adds support for SMP FreeRTOS idle tasks
- Updates startup code TWDT initialization
- Updates API documentation
This commit updates how the TLS pointers deletion callbacks are called
during task deletion in the FreeRTOS SMP kernel. The callbacks are now
routed through the portCLEAN_UP_TCB() macro. This commit also adds a
new kconfig option CONFIG_FREERTOS_TLSP_DELETION_CALLBACKS to control
the enablement of the TLSP deletion callbacks.
This commit disables portUSING_MPU_WRAPPERS for the FreeRTOS SMP xtensa port.
This was previously enabled due to the need to keep a CPSA (coprocessor save
area pointer) in the TCB. The CPSA pointer is now calculated at run time.
This commit updates the usage of idle hooks in SMP FreeRTOS as follows:
- IDF style idle hooks are now called from vApplicationMinimalIdleHook()
- If the user provdies their own vApplicationMinimalIdleHook(), it can be
wrapped using -Wl,--wrap if CONFIG_FREERTOS_USE_MINIMAL_IDLE_HOOK is
enabled.
- SMP port no longer uses vApplicationIdleHook() as it's only called from
the prvIdleTask() and not every prvMinimalIdleTask()
This commit updates the copied Xtensa port to support the new porting interfaces
of the FreeRTOS SMP kernel. These modifications are mainly contained in
- FreeRTOSConfig.h
- FreeRTOSConfig_smp.h
- portmacro.h
- port.c
Some porting interfaces have changed in FreeRTOS SMP. In order to allow building
with IDF, compatibility interfaces have been added.
This commit copies over ESP-IDF Xtensa portable files to the
FreeRTOS-Kernel-SMP directory. No changes were made, this commit
only copies the portable source files.
Notes:
- This commit WILL NOT compile
- Some SPDX header dates were updated to pass pre-commit check
