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Documentation and download available at https://www.FreeRTOS.org/
Changes between FreeRTOS V11.0.1 and FreeRTOS V11.1.0 released April 22, 2024
+ Add ARMv7-R port with Memory Protection Unit (MPU) support.
+ Add Memory Protection Unit (MPU) support to the Cortex-M0 port.
+ Add stream batching buffer. A stream batching buffer differs from a stream
buffer when a task reads from a non-empty buffer:
- The task reading from a non-empty stream buffer returns immediately
regardless of the amount of data in the buffer.
- The task reading from a non-empty steam batching buffer blocks until the
amount of data in the buffer exceeds the trigger level or the block time
expires.
We thank @cperkulator for their contribution.
+ Add the ability to change task notification index for stream buffers. We
thank @glemco for their contribution.
+ Add xStreamBufferResetFromISR and xMessageBufferResetFromISR APIs to reset
stream buffer and message buffer from an Interrupt Service Routine (ISR).
We thank @HagaiMoshe for their contribution.
+ Update all the FreeRTOS APIs to use configSTACK_DEPTH_TYPE for stack type.
We thank @feilipu for their contribution.
+ Update vTaskEndScheduler to delete the timer and idle tasks,
once the scheduler is stopped.
+ Make xTaskGetCurrentTaskHandleForCore() available to the single core
scheduler. We thank @Dazza0 for their contribution.
+ Update uxTaskGetSystemState to not use the pxIndex member of the List_t
structure while iterating ready tasks list. The reason is that pxIndex
member must only used to select next ready task to run. We thank
@gemarcano for their inputs.
+ Add a config option to the FreeRTOS SMP Kernel to set the default core
affinity mask for tasks created without an affinity mask. We thank @go2sh
for their contribution.
+ Add configUSE_EVENT_GROUPS and configUSE_STREAM_BUFFERS configuration
constants to control the inclusion of event group and stream buffer
functionalities.
+ Code changes to comply with MISRA C 2012.
+ Add 64-bit support to the FreeRTOS Windows Simulator port. We thank @watsk
and @josesimoes for their contributions.
+ Add support for 64-bit Microblaze processor to the MicroblazeV9 port. We
thank @mubinsyed for their contribution.
+ Add support for MSP430 Embedded Application Binary Interface (EABI) to
the MSP430F449 port to make it work with both MSP430 GCC and MSPGCC
compilers. We thank @Forty-Bot for their contribution.
+ Update xPortIsAuthorizedToAccessBuffer() on FreeRTOS ports with MPU
support to grant an unprivileged task access to all the memory before the
scheduler is started.
+ Update the POSIX port to pass the FreeRTOS task name to pthread for
readable output in debuggers. We thank @Mixaill for their contribution.
+ Update the POSIX port to ignore the user specified stack memory and only
pass the stack size to the pthread API to avoid errors caused when stack size
is smaller than the minimum. We thank @cmorgnaBE for their
contribution.
+ Update the POSIX port to use a timer thread for tick interrupts instead of
POSIX timers to address issues with signal handling in non-FreeRTOS
pthreads. We thank @cmorgnaBE for their contribution.
+ Update ARM_TFM port to support TF-Mv2.0.0 release of trusted-firmware-m.
We thanks @urutva for their contribution.
+ Remove redundant constant pools in ARMv8 ports. We thank @urutva for their
contribution.
+ Add APIs to reset the internal state of kernel modules. These APIs are
primarily intended to be used in the testing frameworks that restart the
scheduler.
+ Use kernel provided implementations of vApplicationGetIdleTaskMemory() and
vApplicationGetTimerTaskMemory() in the RP2040 port. We thank @dpslwk for
their contribution.
+ Fix atomic enter/exit critical section macro definitions in atomic.h for
ports that support nested interrupts. We thank @sebunger for their
contribution.
+ Fix compiler warnings in the MSP430F449 port when compiled with the
MSP430 GCC compiler. We thank @Forty-Bot for their contribution.
+ Update the scheduler suspension usage in ulTaskGenericNotifyTake and
xTaskGenericNotifyWait() to enhance code readability. We thank @Dazza0 for
their contribution.
+ Add support for latest version of MPU wrappers( mpu_wrappers_v2) in CMake.
We thank @IsaacDynamo for their contribution.
+ Update CMake support to create only one static library containing both the
kernel common code and the kernel port code. We thank @barnatahmed for
their contribution.
Changes between FreeRTOS V11.0.0 and FreeRTOS V11.0.1 released December 21, 2023
+ Updated the SBOM file.
Changes between FreeRTOS V10.6.2 and FreeRTOS V11.0.0 released December 18, 2023
+ SMP merged into the mainline: While FreeRTOS introduced Asymmetric
Multiprocessing (AMP) support in 2017, FreeRTOS Version 11.0.0 is the
first to merge Symmetric Multiprocessing (SMP) support into the mainline
release. SMP enables one instance of the FreeRTOS Kernel to schedule tasks
across multiple identical processor cores. We thank Mike Bruno and Jerry
McCarthy of XMOS and, Darian Liang, Sudeep Mohanty and Zim Kalinowski of
Espressif Systems for their contributions.
+ Switch MISRA compliance checking from PC Lint to Coverity, and update from
MISRA C:2004 to MISRA C:2012.
+ Add a template FreeRTOSConfig.h, inclusive of an abbreviated explanation of
each configuration item. Application writers can use this template as a
starting point to create the FreeRTOSConfig.h file for their application.
+ Add a template FreeRTOS port which can be used as a starting point for
developing a new FreeRTOS port.
+ Add bounds checking and obfuscation to internal heap block pointers in
heap_4.c and heap_5.c to help catch pointer corruptions. The application can
enable these checks by setting configENABLE_HEAP_PROTECTOR to 1 in their
FreeRTOSConfig.h. We thank @oliverlavery for their contribution.
+ Update vTaskList and vTaskGetRunTimeStats APIs to replace the use of sprintf
with snprintf.
+ Add trace macros to ports that enable tracing the interaction of ISRs with
scheduler events. We thank @conara for their contribution.
+ Add trace macros that enable tracing of entering and exiting all APIs. We
thank @Techcore123 for their contribution.
+ Add uxTaskBasePriorityGet and uxTaskBasePriorityGetFromISR APIs to get the
base priority of a task. The base priority of a task is the priority that
was last assigned to the task - which due to priority inheritance, may not
be the current priority of the task.
+ Add pdTICKS_TO_MS macro to convert time in FreeRTOS ticks to time in
milliseconds. We thank @Dazza0 for their contribution.
+ Add default implementations of vApplicationGetIdleTaskMemory and
vApplicationGetTimerTaskMemory. The application can enable these default
implementations by setting configKERNEL_PROVIDED_STATIC_MEMORY to 1 in their
FreeRTOSConfig.h. We thank @mdnr-g for their contribution.
+ Update vTaskGetInfo to include start and end of the stack whenever both
values are available. We thank @vinceburns for their contribution.
+ Prevent tasks waiting for a notification from being resumed by calls to
vTaskResume or vTaskResumeFromISR. We thank @Moral-Hao for their
contribution.
+ Add asserts to validate that the application has correctly installed
FreeRTOS handlers for PendSV and SVCall interrupts on Cortex-M devices.
We thank @jefftenney for their contribution.
+ Rename ARM_CA53_64_BIT and ARM_CA53_64_BIT_SRE ports to Arm_AARCH64 and
Arm_AARCH64_SRE respectively as these ports are applicable to all AArch64
architecture. We thank @urutva for their contribution.
+ Add CMake support to allow the application writer to select the RISC-V
chip extension. We thank @JoeBenczarski for their contribution.
+ Add CMake support to allow the application writer to build an application
with static allocation only. We thank @conara for their contribution.
+ Make taskYIELD available to unprivileged tasks for ARMv8-M ports.
+ Update Cortex-M23 ports to not use PSPLIM_NS. We thank @urutva for their
contribution.
+ Update the SysTick setup code for ARMv8-M ports to first configure the clock
source and then enable SysTick. This is needed to address a bug in QEMU
versions older than 7.0.0, which causes an emulation error if SysTick is
enabled without first selecting a valid clock source. We thank @jefftenney
for their contribution.
+ Add the port-optimized task selection algorithm optionally available for
ARMv7-M ports to the ARMv8-M ports. We thank @jefftenney for their
contribution.
+ Improve the speed of pvPortMalloc in heap_4.c and heap_5.c by removing
unnecessary steps while splitting a large memory block into two. We thank
@Moral-Hao for their contribution.
+ Shorten the critical section in pvPortMalloc in heap_2.c, heap_4.c and
heap_5.c by moving the size calculation out of the critical section. We thank
@Moral-Hao for their contribution.
+ Update xTaskNotifyWait and ulTaskNotifyTake to remove the non-deterministic
operation of traversing a linked link from a critical section. We thank
@karver8 for their contribution.
+ Fix stack end and stack size computation in POSIX port to meet the stack
alignment requirements on MacOS. We thank @tegimeki for their contribution.
+ Update the vTaskPrioritySet implementation to use the new priority when the
task has inherited priority from a mutex it is holding, and the new priority
is bigger than the inherited priority. We thank @Moral-Hao for their
contribution.
+ Add stack alignment adjustment if stack grows upwards. We thank @ivq for
their contribution.
+ Fix pxTopOfStack calculation in configINIT_TLS_BLOCK when picolib C is
selected as the C library implementation to ensure that
pxPortInitialiseStack does not overwrite the data in the TLS block portion
of the stack. We thank @bebebib-rs for their contribution.
+ Fix vPortEndScheduler() for the MSVC port so that the function
prvProcessSimulatedInterrupts is not stuck in an infinite loop when the
scheduler is stopped. We thank @Ju1He1 for their contribution.
+ Add the Pull Request (PR) Process explaining the stages a PR goes through.
Changes between FreeRTOS V10.6.1 and FreeRTOS V10.6.2 released November 29, 2023
+ Add the following improvements to the new MPU wrapper (mpu_wrappers_v2.c)
introduced in version 10.6.0:
- Introduce Access Control List (ACL) feature to allow the application
writer to control an unprivileged task’s access to kernel objects.
- Update the system call entry mechanism to only require one Supervisor
Call (SVC) instruction.
- Wrap parameters for system calls with more than four parameters in a
struct to avoid special handling during system call entry.
- Fix 2 possible integer overflows.
- Convert some asserts to run time parameter checks.
Changes between FreeRTOS V10.6.0 and FreeRTOS V10.6.1 released August 17, 2023
+ Add runtime parameter checks to functions in mpu_wrappers_v2.c file.
The same checks are already performed in API implementations using
asserts.
We thank the following people for their inputs in these changes:
- Lan Luo, Zixia Liu of School of Computer Science and Technology,
Anhui University of Technology, China.
- Xinwen Fu of Department of Computer Science, University of
Massachusetts Lowell, USA.
- Xinhui Shao, Yumeng Wei, Huaiyu Yan, Zhen Ling of School of
Computer Science and Engineering, Southeast University, China.
Changes between FreeRTOS V10.5.1 and FreeRTOS 10.6.0 released July 13, 2023
+ Add a new MPU wrapper that places additional restrictions on unprivileged
tasks. The following is the list of changes introduced with the new MPU
wrapper:
1. Opaque and indirectly verifiable integers for kernel object handles:
All the kernel object handles (for example, queue handles) are now
opaque integers. Previously object handles were raw pointers.
2. Save the task context in Task Control Block (TCB): When a task is
swapped out by the scheduler, the task's context is now saved in its
TCB. Previously the task's context was saved on its stack.
3. Execute system calls on a separate privileged only stack: FreeRTOS
system calls, which execute with elevated privilege, now use a
separate privileged only stack. Previously system calls used the
calling task's stack. The application writer can control the size of
the system call stack using new configSYSTEM_CALL_STACK_SIZE config
macro.
4. Memory bounds checks: FreeRTOS system calls which accept a pointer
and de-reference it, now verify that the calling task has required
permissions to access the memory location referenced by the pointer.
5. System calls restrictions: The following system calls are no longer
available to unprivileged tasks:
- vQueueDelete
- xQueueCreateMutex
- xQueueCreateMutexStatic
- xQueueCreateCountingSemaphore
- xQueueCreateCountingSemaphoreStatic
- xQueueGenericCreate
- xQueueGenericCreateStatic
- xQueueCreateSet
- xQueueRemoveFromSet
- xQueueGenericReset
- xTaskCreate
- xTaskCreateStatic
- vTaskDelete
- vTaskPrioritySet
- vTaskSuspendAll
- xTaskResumeAll
- xTaskGetHandle
- xTaskCallApplicationTaskHook
- vTaskList
- vTaskGetRunTimeStats
- xTaskCatchUpTicks
- xEventGroupCreate
- xEventGroupCreateStatic
- vEventGroupDelete
- xStreamBufferGenericCreate
- xStreamBufferGenericCreateStatic
- vStreamBufferDelete
- xStreamBufferReset
Also, an unprivileged task can no longer use vTaskSuspend to suspend
any task other than itself.
We thank the following people for their inputs in these enhancements:
- David Reiss of Meta Platforms, Inc.
- Lan Luo, Xinhui Shao, Yumeng Wei, Zixia Liu, Huaiyu Yan and Zhen Ling
of School of Computer Science and Engineering, Southeast University,
China.
- Xinwen Fu of Department of Computer Science, University of
Massachusetts Lowell, USA.
- Yueqi Chen, Zicheng Wang, Minghao Lin, Jiahe Wang of University of
Colorado Boulder, USA.
+ Add Cortex-M35P port. Contributed by @urutva.
+ Add embedded extension (RV32E) support to the IAR RISC-V port.
+ Add ulTaskGetRunTimeCounter and ulTaskGetRunTimePercent APIs. Contributed by
@chrisnc.
+ Add APIs to get the application supplied buffers from statically
created kernel objects. The following new APIs are added:
- xTaskGetStaticBuffers
- xQueueGetStaticBuffers
- xQueueGenericGetStaticBuffers
- xSemaphoreGetStaticBuffer
- xEventGroupGetStaticBuffer
- xStreamBufferGetStaticBuffers
- xMessageBufferGetStaticBuffers
These APIs enable the application writer to obtain static buffers from
the kernel object and free/reuse them at the time of deletion. Earlier
the application writer had to maintain the association of static buffers
and the kernel object in the application. Contributed by @Dazza0.
+ Add Thread Local Storage (TLS) support using picolibc function. Contributed
by @keith-packard.
+ Add configTICK_TYPE_WIDTH_IN_BITS to configure TickType_t data type. As a result,
the number of bits in an event group also increases with big data type. Contributed
by @Hadatko.
+ Update eTaskGetState and uxTaskGetSystemState to return eReady for pending ready
tasks. Contributed by @Dazza0.
+ Update heap_4 and heap_5 to add padding only if the resulting block is not
already aligned.
+ Fix the scheduler logic in a couple of places to not preempt a task when an
equal priority task becomes ready.
+ Add macros used in FreeRTOS-Plus libraries. Contributed by @Holden.
+ Fix clang compiler warnings. Contributed by @phelter.
+ Add assertions to ARMv8-M ports to detect when FreeRTOS APIs are called from
interrupts with priority higher than the configMAX_SYSCALL_INTERRUPT_PRIORITY.
Contributed by @urutva.
+ Add xPortIsInsideInterrupt API to ARM_CM0 ports.
+ Fix build warning in MSP430X port when large data model is used.
+ Add the ability to use Cortex-R5 port on the parts without FPU.
+ Fix build warning in heap implementations on PIC24/dsPIC.
+ Update interrupt priority asserts for Cortex-M ports so that these do not fire
on QEMU which does not implement PRIO bits.
+ Update ARMv7-M ports to ensure that kernel interrupts run at the lowest priority.
configKERNEL_INTERRUPT_PRIORITY is now obsolete for ARMv7-M ports and brings
these ports inline with the newer ARMv8-M ports. Contributed by @chrisnc.
+ Fix build issue in POSIX GCC port on Windows Subsystem for Linux (WSL). Contributed
by @jacky309.
+ Add portMEMORY_BARRIER to Microblaze port. Contributed by @bbain.
+ Add portPOINTER_SIZE_TYPE definition for ATmega port. Contributed by @jputcu.
+ Multiple improvements in the CMake support. Contributed by @phelte and @cookpate.
Changes between FreeRTOS V10.5.0 and FreeRTOS V10.5.1 released November 16 2022
+ Updated the kernel version in manifest and SBOM
Changes between FreeRTOS V10.4.6 and FreeRTOS V10.5.0 released September 16 2022
+ ARMv7-M and ARMv8-M MPU ports: It was possible for a third party that
already independently gained the ability to execute injected code to
read from or write to arbitrary addresses by passing a negative argument
as the xIndex parameter to pvTaskGetThreadLocalStoragePointer() or
vTaskSetThreadLocalStoragePointer respectively. A check has been added to
ensure that passing a negative argument as the xIndex parameter does not
cause arbitrary read or write.
We thank Certibit Consulting, LLC for reporting this issue.
+ ARMv7-M and ARMv8-M MPU ports: It was possible for an unprivileged task
to invoke any function with privilege by passing it as a parameter to
MPU_xTaskCreate, MPU_xTaskCreateStatic, MPU_xTimerCreate,
MPU_xTimerCreateStatic, or MPU_xTimerPendFunctionCall. MPU_xTaskCreate
and MPU_xTaskCreateStatic have been updated to only allow creation of
unprivileged tasks. MPU_xTimerCreate, MPU_xTimerCreateStatic and
MPU_xTimerPendFunctionCall APIs have been removed.
We thank Huazhong University of Science and Technology for reporting
this issue.
+ ARMv7-M and ARMv8-M MPU ports: It was possible for a third party that
already independently gained the ability to execute injected code to
achieve further privilege escalation by branching directly inside a
FreeRTOS MPU API wrapper function with a manually crafted stack frame.
The local stack variable `xRunningPrivileged` has been removed so that
a manually crafted stack frame cannot be used for privilege escalation
by branching directly inside a FreeRTOS MPU API wrapper.
We thank Certibit Consulting, LLC, Huazhong University of Science and
Technology and the SecLab team at Northeastern University for reporting
this issue.
+ ARMv7-M MPU ports: It was possible to configure overlapping memory
protection unit (MPU) regions such that an unprivileged task could access
privileged data. The kernel now uses highest numbered MPU regions for
kernel protections to prevent such MPU configurations.
We thank the SecLab team at Northeastern University for reporting this
issue.
+ Add support for ARM Cortex-M55.
+ Add support for ARM Cortex-M85. Contributed by @gbrtth.
+ Add vectored mode interrupt support to the RISC-V port.
+ Add support for RV32E extension (Embedded Profile) in RISC-V GCC port.
Contributed by @Limoto.
+ Heap improvements:
- Add a check to heap_2 to track if a memory block is allocated to
the application or not. The MSB of the size field is used for this
purpose. The same check already exists in heap_4 and heap_5. This
check prevents double free errors.
- Add a new flag configHEAP_CLEAR_MEMORY_ON_FREE to heap_2, heap_4
and heap_5. If the flag is set in FreeRTOSConfig.h then memory freed using
vPortFree() is automatically cleared to zero.
- Add a new API pvPortCalloc to heap_2, heap_4 and heap_5 which has the same
signature as the standard library calloc function.
- Update the pointer types to portPOINTER_SIZE_TYPE. Contributed by
@Octaviarius.
+ Add the ability to override send and receive completed callbacks for each
instance of a stream buffer or message buffer. Earlier there could be
one send and one receive callback for all instances of stream and message
buffers. Having separate callbacks per instance allows different message
and stream buffers to be used differently - for example, some for inter core
communication and others for same core communication.
The feature can be controlled by setting the configuration option
configUSE_SB_COMPLETED_CALLBACK in FreeRTOSConfig.h. When the option is set to 1,
APIs xStreamBufferCreateWithCallback() or xStreamBufferCreateStaticWithCallback()
(and likewise APIs for message buffer) can be used to create a stream buffer
or message buffer instance with application provided callback overrides. When
the option is set to 0, then the default callbacks as defined by
sbSEND_COMPLETED() and sbRECEIVE_COMPLETED() macros are invoked. To maintain
backwards compatibility, configUSE_SB_COMPLETED_CALLBACK defaults to 0. The
functionality is currently not supported for MPU enabled ports.
+ Generalize the FreeRTOS's Thread Local Storage (TLS) support so that it
is not tied to newlib and can be used with other c-runtime libraries also.
The default behavior for newlib support is kept same for backward
compatibility.
+ Add support to build and link FreeRTOS using CMake build system. Contributed
by @yhsb2k.
+ Add support to generate Software Bill of Materials (SBOM) for every release.
+ Add support for 16 MPU regions to the GCC Cortex-M33 ports.
+ Add ARM Cortex-M7 r0p0/r0p1 Errata 837070 workaround to ARM CM4 MPU ports.
The application writer needs to define configENABLE_ERRATA_837070_WORKAROUND
when using CM4 MPU ports on a Cortex-M7 r0p0/r0p1 core.
+ Add configSYSTICK_CLOCK_HZ to Cortex-M0 ports. This is needed to support
the case when the SysTick timer is not clocked from the same source as the CPU.
+ Add hardware stack protection support to MicroBlazeV9 port. This ensures that
the CPU immediately raises Stack Protection Violation exception as soon as any
task violates its stack limits. Contributed by @uecasm.
+ Introduce the configUSE_MINI_LIST_ITEM configuration option. When this
option is set to 1, ListItem_t and MiniLitItem_t remain separate types.
However, when configUSE_MINI_LIST_ITEM == 0, MiniLitItem_t and ListItem_t
are both typedefs of the same struct xLIST_ITEM. This addresses some issues
observed when strict-aliasing and link time optimization are enabled.
To maintain backwards compatibility, configUSE_MINI_LIST_ITEM defaults to 1.
+ Simplify prvInitialiseNewTask to memset newly allocated TCB structures
to zero, and remove code that set individual structure members to zero.
+ Add prototype for prvPortYieldFromISR to the POSIX port so that it builds
without any warning with -Wmissing-prototypes compiler option.
+ Add top of stack and end of stack to the task info report obtained using
vTaskGetInfo(). Contributed by @shreyasbharath.
+ Add a cap to the cRxLock and cTxLock members of the queue data structure.
These locks count the number items received and sent to the queue while
the queue was locked. These are later used to unblock tasks waiting on
the queue when the queue is unlocked. This PR caps the values of the
cRxLock and cTxLock to the number of tasks in the system because we cannot
unblock more tasks than there are in the system. Note that the same assert
could still be triggered is the application creates more than 127 tasks.
+ Changed uxAutoReload parameter in timer functions to xAutoReload. The
type is now BaseType_t. This matches the type of pdTRUE and pdFALSE.
The new function xTimerGetAutoReload() provides the auto-reload state as
a BaseType_t. The legacy function uxTimerGetAutoReload is retained with the
original UBaseType_t return value.
+ Fix support for user implementations of tickless idle that call
vTaskStepTick() with xExpectedIdleTime ticks to step. The new code
ensures xTickCount reaches xNextTaskUnblockTime inside xTaskIncrementTick()
instead of inside vTaskStepTick(). This fixes the typical case where a task
wakes up one tick late and a rare case assertion failure when xTickCount\
rolls over. Contributed by @jefftenney.
+ Fix deadlock in event groups when pvPortMalloc and vPortFree functions
are protected with a mutex. Contributed by @clemenskresser.
+ Fix a warning in tasks.c when compiled with -Wduplicated-branches
GCC option. Contributed by @pierrenoel-bouteville-act.
+ Fix compilation error in tasks.c when configSUPPORT_DYNAMIC_ALLOCATION
is set to zero. Contributed by @rdpoor.
+ Fix prvWriteMessageToBuffer() function in stream_buffer.c so that it correctly
copies length on big endian platforms too.
+ Remove the need for INCLUDE_vTaskSuspend to be set to 1
when configUSE_TICKLESS_IDLE is enabled. Contributed by @pramithkv.
+ Update the RL78 IAR port to the latest version of IAR which uses the
industry standard ELF format as opposed to earlier UBROF object format.
Contributed by @felipe-iar.
+ Add tick type is atomic flag when tick count is 16-bit to PIC24 port. This
allows the PIC24 family of 16 bit processors to read the tick count without
a critical section when the tick count is also 16 bits.
+ Fix offset-out-of-range errors for GCC CM3/CM4 mpu ports when
Link Time Optimization is enabled. Contributed by @niniemann.
+ Remove #error when RISC-V port is compiled on a 64-bit RISC-V platform.
Contributed by @cmdrf.
+ Fix ullPortInterruptNesting alignment in Cortex-A53 port so that it is
8-byte aligned. This fixes the unaligned access exception. Contributed
by @Atomar25.
+ Fix Interrupt Handler Register Function and Exception Process in NiosII
Port. Contributed by @ghost.
+ Change FreeRTOS IRQ Handler for Cortex-A53 SRE port to store and restore
interrupt acknowledge register. This ensures that the SRE port behavior
matches the Memory Mapped IO port. Contributed by @sviaunxp.
+ Update the uncrustify config file to match the version of the uncrustify
used in the CI Action. Also, pin the version of uncrustify in CI. Contributed
by @swaldhoer.
Changes between FreeRTOS V10.4.5 and FreeRTOS V10.4.6 released November 12 2021
+ ARMv7-M and ARMv8-M MPU ports – prevent non-kernel code from calling the
internal functions xPortRaisePrivilege and vPortResetPrivilege by changing
them to macros.
+ Introduce a new config configALLOW_UNPRIVILEGED_CRITICAL_SECTIONS which
enables developers to prevent critical sections from unprivileged tasks.
It defaults to 1 for backward compatibility. Application should set it to
0 to disable critical sections from unprivileged tasks.
Changes between FreeRTOS V10.4.4 and FreeRTOS V10.4.5 released September 10 2021
See https://www.FreeRTOS.org/FreeRTOS-V10.4.5.html
+ Introduce configRUN_TIME_COUNTER_TYPE which enables developers to define
the type used to hold run time statistic counters. Defaults to uint32_t
for backward compatibility. #define configRUN_TIME_COUNTER_TYPE to a type
(for example, uint64_t) in FreeRTOSConfig.h to override the default.
+ Introduce ulTaskGetIdleRunTimePercent() to complement the pre-existing
ulTaskGetIdleRunTimeCounter(). Whereas the pre-existing function returns
the raw run time counter value, the new function returns the percentage of
the entire run time consumed by the idle task. Note the amount of idle
time is only a good measure of the slack time in a system if there are no
other tasks executing at the idle priority, tickless idle is not used, and
configIDLE_SHOULD_YIELD is set to 0.
+ ARMv8-M secure-side port: Tasks that call secure functions from the
non-secure side of an ARMv8-M MCU (ARM Cortex-M23 and Cortex-M33) have two
contexts - one on the non-secure side and one on the secure-side. Previous
versions of the FreeRTOS ARMv8-M secure-side ports allocated the structures
that reference secure-side contexts at run time. Now the structures are
allocated statically at compile time. The change necessitates the
introduction of the secureconfigMAX_SECURE_CONTEXTS configuration constant,
which sets the number of statically allocated secure contexts.
secureconfigMAX_SECURE_CONTEXTS defaults to 8 if left undefined.
Applications that only use FreeRTOS code on the non-secure side, such as
those running third-party code on the secure side, are not affected by
this change.
Changes between FreeRTOS V10.4.3 and FreeRTOS V10.4.4 released May 28 2021
+ Minor performance improvements to xTaskIncrementTick() achieved by providing
macro versions of uxListRemove() and vListInsertEnd().
+ Minor refactor of timers.c that obsoletes the need for the
tmrCOMMAND_START_DONT_TRACE macro and removes the need for timers.c to
post to its own event queue. A consequence of this change is that auto-
reload timers that miss their intended next execution time will execute
again immediately rather than executing again the next time the command
queue is processed. (thanks Jeff Tenney).
+ Fix a race condition in the message buffer implementation. The
underlying cause was that length and data bytes are written and read as
two distinct operations, which both modify the size of the buffer. If a
context switch occurs after adding or removing the length bytes, but
before adding or removing the data bytes, then another task may observe
the message buffer in an invalid state.
+ The xTaskCreate() and xTaskCreateStatic() functions accept a task priority
as an input parameter. The priority has always been silently capped to
(configMAX_PRIORITIES - 1) should it be set to a value above that priority.
Now values above that priority will also trigger a configASSERT() failure.
+ Replace configASSERT( pcQueueName ) in vQueueAddToRegistry with a NULL
pointer check.
+ Introduce the configSTACK_ALLOCATION_FROM_SEPARATE_HEAP configuration
constant that enables the stack allocated to tasks to come from a heap other
than the heap used by other memory allocations. This enables stacks to be
placed within special regions, such as fast tightly coupled memory.
+ If there is an attempt to add the same queue or semaphore handle to the
queue registry more than once then prior versions would create two separate
entries. Now if this is done the first entry is overwritten rather than
duplicated.
+ Update the ESP32 port and TF-M (Trusted Firmware M)code to the latest from
their respective repositories.
+ Correct a build error in the POSIX port.
+ Additional minor formatting updates, including replacing tabs with spaces
in more files.
+ Other minor updates include adding additional configASSERT() checks and
correcting and improving code comments.
+ Go look at the smp branch to see the progress towards the Symmetric
Multiprocessing Kernel. https://github.com/FreeRTOS/FreeRTOS-Kernel/tree/smp
Changes between FreeRTOS V10.4.2 and FreeRTOS V10.4.3 released December 14 2020
V10.4.3 is included in the 202012.00 LTS release. Learn more at https:/freertos.org/lts-libraries.html
See https://www.FreeRTOS.org/FreeRTOS-V10.4.x.html
+ Changes to improve robustness and consistency for buffer allocation in
the heap, queue and stream buffer.
+ The following functions can no longer be called from unprivileged code.
- xTaskCreateRestricted
- xTaskCreateRestrictedStatic
- vTaskAllocateMPURegions
Changes between FreeRTOS V10.4.1 and FreeRTOS V10.4.2 released November 10 2020
See https://www.FreeRTOS.org/FreeRTOS-V10.4.x.html
+ Fix an issue in the ARMv8-M ports that caused BASEPRI to be masked
between the first task starting to execute and that task making
a FreeRTOS API call.
+ Introduced xTaskDelayUntil(), which is functionally equivalent to
vTaskDelayUntil(), with the addition of returning a value to
indicating whether or not the function placed the calling task into
the Blocked state or not.
+ Update WolfSSL to 4.5.0 and add the FIPS ready demo.
+ Add support for ESP IDF 4.2 to ThirdParty Xtensa port.
+ Re-introduce uxTopUsedPriority to support OpenOCD debugging.
+ Convert most dependent libraries in FreeRTOS/FreeRTOS to submodules.
+ Various general maintenance and improvements to MISRA compliance.
Changes between FreeRTOS V10.4.0 and FreeRTOS V10.4.1 released September 17 2020
See https://www.FreeRTOS.org/FreeRTOS-V10.4.x.html
+ Fixed an incorrectly named parameter that prevented the
ulTaskNotifyTakeIndexed macro compiling, and the name space clash in the
test code that prevented this error causing test failures.
Changes between FreeRTOS V10.3.1 and FreeRTOS V10.4.0 released September 10 2020
See https://www.FreeRTOS.org/FreeRTOS-V10.4.x.html
Major enhancements:
+ Task notifications: Prior to FreeRTOS V10.4.0 each created task had a
single direct to task notification. From FreeRTOS V10.4.0 each task has
an array of notifications. The direct to task notification API has been
extended with API functions postfixed with "Indexed" to enable the API to
operate on a task notification at any array index. See
https://www.freertos.org/RTOS-task-notifications.html for more information.
+ Kernel ports that support memory protection units (MPUs): The ARMv7-M and
ARMv8-M MPU ports now support a privilege access only heap. The ARMv7-M
MPU ports now support devices that have 16 MPU regions, have the ability
to override default memory attributes for privileged code and data
regions, and have the ability to place the FreeRTOS kernel code outside of
the Flash memory. The ARMv8-M MPU ports now support tickless idle mode.
See https://www.freertos.org/FreeRTOS-MPU-memory-protection-unit.html
for more information.
Additional noteworthy updates:
+ Code formatting is now automated to facilitate the increase in
collaborative development in Git. The auto-formated code is not identical
to the original formatting conventions. Most notably spaces are now used
in place of tabs.
+ The prototypes for callback functions (those that start with "Application",
such as vApplicationStackOverflowHook()) are now in the FreeRTOS header
files, removing the need for application writers to add prototypes into
the C files in which they define the functions.
+ New Renesas RXv3 port layer.
+ Updates to the Synopsys ARC code, including support for EM and HS cores,
and updated BSP.
+ Added new POSIX port layer that allows FreeRTOS to run on Linux hosts in
the same way the Windows port layer enables FreeRTOS to run on Windows
hosts.
+ Many other minor optimisations and enhancements. For full details
see https://github.com/FreeRTOS/FreeRTOS-Kernel/commits/main
Changes between FreeRTOS V10.3.0 and FreeRTOS V10.3.1 released February 18 2020
See https://www.FreeRTOS.org/FreeRTOS-V10.3.x.html
+ ./FreeRTOS-Labs directory was removed from this file. The libraries it
contained are now available as a separate download.
Changes between FreeRTOS V10.2.1 and FreeRTOS V10.3.0 released February 7 2020
See https://www.FreeRTOS.org/FreeRTOS-V10.3.x.html
New and updated kernel ports:
+ Added RISC-V port for the IAR compiler.
+ Update the Windows simulator port to use a synchronous object to prevent
a user reported error whereby a task continues to run for a short time
after being moved to the Blocked state. Note we were not able to
replicate the reported issue and it likely depends on your CPU model.
+ Correct alignment of stack top in RISC-V port when
configISR_STACK_SIZE_WORDS is defined to a non zero value, which causes
the interrupt stack to be statically allocated.
+ The RISC-V machine timer compare register can now be for any HART, whereas
previously it was always assumed FreeRTOS was running on HART 0.
+ Update the sequence used to update the 64-bit machine timer
compare register on 32-bit cores to match that suggested in RISC-V
documentation.
+ Added tickless low power modes into the ARM, IAR and GCC Cortex-M0 compiler
ports.
+ Updated the behaviour of the ARMv7-M MPU (Memory Protection Unit) ports to
match that of the ARMv8-M ports whereby privilege escalations can only
originate from within the kernel's own memory segment. Added
configENFORCE_SYSTEM_CALLS_FROM_KERNEL_ONLY configuration constant.
+ Update existing MPU ports to correctly disable the MPU before it is
updated.
+ Added contributed port and demo application for a T-Head (formally C-SKY)
microcontroller.
New API functions:
+ Added the vPortGetHeapStats() API function which returns information on
the heap_4 and heap_5 state.
+ Added xTaskCatchUpTicks(), which corrects the tick count value after the
application code has held interrupts disabled for an extended period.
+ Added xTaskNotifyValueClear() API function.
+ Added uxTimerGetReloadMode() API function.
Other miscellaneous changes:
+ Change type of uxPendedTicks from UBaseType_t to TickType_t to ensure it
has the same type as variables with which it is compared to, and therefore
also renamed the variable xPendingTicks.
+ Update Keil projects that use the MPU so memory regions come from linker
script (scatter file) variables instead of being hard coded.
+ Added LPC51U68 Cortex-M0+ demos for GCC (MCUXpresso), Keil and IAR
compilers.
+ Added CORTEX_MPU_STM32L4_Discovery_Keil_STM32Cube demo.
+ Added LPC54018 MPU demo.
+ Rename xTaskGetIdleRunTimeCounter() to ulTaskGetIdleRunTimeCounter().
Changes between FreeRTOS V10.2.1 and FreeRTOS V10.2.0 released May 13 2019:
+ Added ARM Cortex-M23 port layer to complement the pre-existing ARM
Cortex-M33 port layer.
+ The RISC-V port now automatically switches between 32-bit and 64-bit
cores.
+ Introduced the portMEMORY_BARRIER macro to prevent instruction re-ordering
when GCC link time optimisation is used.
+ Introduced the portDONT_DISCARD macro to the ARMv8-M ports to try and
prevent the secure side builds from removing symbols required by the
non secure side build.
+ Introduced the portARCH_NAME to provide additional data to select semi-
automated build environments.
+ Cortex-M33 and Cortex-M23 ports now correctly disable the MPU before
updating the MPU registers.
+ Added Nuvoton NuMaker-PFM-M2351 ARM Cortex-M23 demo.
+ Added LPC55S69 ARM Cortex-M33 demo.
+ Added an STM32 dual core AMP stress test demo.
Changes between FreeRTOS V10.1.1 and FreeRTOS V10.2.0 released February 25 2019:
+ Added GCC RISC-V MCU port with three separate demo applications.
+ Included pre-existing ARM Cortex-M33 (ARMv8-M) GCC/ARMclang and IAR ports
with Keil simulator demo.
+ Update the method used to detect if a timer is active. Previously the
timer was deemed to be inactive if it was not referenced from a list.
However, when a timer is updated it is temporarily removed from, then
re-added to a list, so now the timer's active status is stored separately.
+ Add vTimerSetReloadMode(), xTaskGetIdleRunTimeCounter(), and
xTaskGetApplicationTaskTagFromISR() API functions.
+ Updated third party Xtensa port so it is MIT licensed.
+ Added configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H to the Renesas
compiler RX600v2 port to enable switching between platform.h and
iodefine.h includes within that port's port.c file.
+ Removed the 'FromISR' functions from the MPU ports as ISRs run privileged
anyway.
+ Added uxTaskGetStackHighWaterMark2() function to enable the return type to
be changed without breaking backward compatibility.
uxTaskGetStackHighWaterMark() returns a UBaseType_t as always,
uxTaskGetStackHighWaterMark2() returns configSTACK_DEPTH_TYPE to allow the
user to determine the return type.
+ Fixed issues in memory protected ports related to different combinations
of static memory only and dynamic memory only builds. As a result the
definition of tskSTATIC_AND_DYNAMIC_ALLOCATION_POSSIBLE became more
complex and was moved to FreeRTOS.h with a table explaining its definition.
+ Added a 'get task tag from ISR' function.
+ Change the method used to determine if a timer is active or not from just
seeing if it is referenced from the active timer list to storing its
active state explicitly. The change prevents the timer reporting that it
is inactive while it is being moved from one list to another.
+ The pcName parameter passed into the task create functions can be NULL,
previously a name had to be provided.
+ When using tickless idle, prvResetNextTaskUnblockTime() is now only called
in xTaskRemoveFromEventList() if the scheduler is not suspended.
+ Introduced portHAS_STACK_OVERFLOW_CHECKING, which should be set to 1 for
FreeRTOS ports that run on architectures that have stack limit registers.
Changes between FreeRTOS V10.1.0 and FreeRTOS V10.1.1 released 7 September 2018
+ Reverted a few structure name changes that broke several kernel aware
debugger plug-ins.
+ Updated to the latest trace recorder code.
+ Fixed some formatting in the FreeRTOS+TCP TCP/IP stack code.
+ Reverted moving some variables from file to function scope as doing so
broke debug scenarios that require the static qualifier to be removed.
Changes between FreeRTOS V10.0.1 and FreeRTOS V10.1.0 released 22 August 2018
FreeRTOS Kernel Changes:
+ Update lint checked MISRA compliance to use the latest MISRA standard, was
previously using the original MISRA standard.
+ Updated all object handles (TaskHandle_t, QueueHandle_t, etc.) to be
unique types instead of void pointers, improving type safety. (this was
attempted some years back but had to be backed out due to bugs in some
debuggers). Note this required the pvContainer member of a ListItem_t
struct to be renamed - set configENABLE_BACKWARD_COMPATIBILITY to 1 if
this causes an issue.
+ Added configUSE_POSIX_ERRNO to enable per task POSIX style errno
functionality in a more user friendly way - previously the generic thread
local storage feature was used for this purpose.
+ Added Xtensa port and demo application for the XCC compiler.
+ Changed the implementation of vPortEndScheduler() for the Win32 port to
simply call exit( 0 ).
+ Bug fix in vPortEnableInterrupt() for the GCC Microblaze port to protect
the read modify write access to an internal Microblaze register.
+ Fix minor niggles when the MPU is used with regards to prototype
differences, static struct size differences, etc.
+ The usStackHighWaterMark member of the TaskStatus_t structure now has type
configSTACK_DEPTH_TYPE in place of uint16_t - that change should have been
made when the configSTACK_DEPTH_TYPE type (which gets around the previous
16-bit limit on stack size specifications) was introduced.
+ Added the xMessageBufferNextLengthBytes() API function and likewise stream
buffer equivalent.
+ Introduce configMESSAGE_BUFFER_LENGTH_TYPE to allow the number of bytes
used to hold the length of a message in the message buffer to be reduced.
configMESSAGE_BUFFER_LENGTH_TYPE default to size_t, but if, for example,
messages can never be more than 255 bytes it could be set to uint8_t,
saving 3 bytes each time a message is written into the message buffer
(assuming sizeof( size_t ) is 4).
+ Updated the StaticTimer_t structure to ensure it matches the size of the
Timer_t structure when the size of TaskFunction_t does not equal the size
of void *.
+ Update various Xilinx demos to use 2018.1 version of the SDK tools.
+ Various updates to demo tasks to maintain test coverage.
+ FreeRTOS+UDP was removed in FreeRTOS V10.1.0 as it was replaced by
FreeRTOS+TCP, which was brought into the main download in FreeRTOS
V10.0.0. FreeRTOS+TCP can be configured as a UDP only stack, and
FreeRTOS+UDP does not contain the patches applied to FreeRTOS+TCP.
FreeRTOS+TCP Changes:
+ Multiple security improvements and fixes in packet parsing routines, DNS
caching, and TCP sequence number and ID generation.
+ Disable NBNS and LLMNR by default.
+ Add TCP hang protection by default.
We thank Ori Karliner of Zimperium zLabs Team for reporting these issues.
Changes between FreeRTOS V10.0.0 and FreeRTOS V10.0.1, released December 20 2017
+ Fix position of "#if defined( __cplusplus )" in stream_buffer.h.
+ Correct declarations of MPU_xQueuePeek() and MPU_xQueueSemaphoreTake() in
mpu_prototypes.h.
+ Correct formatting in vTaskList() helper function when it prints the state
of the currently executing task.
+ Introduce #error if stream_buffer.c is built without
configUSE_TASK_NOTIFICATIONS set to 1.
+ Update FreeRTOS+TCP to V2.0.0
- Improve the formatting of text that displays the available netword
interfaces when FreeRTOS+TCP is used on Windows with WinPCap.
- Introduce ipconfigSOCKET_HAS_USER_WAKE_CALLBACK option to enable a user
definable callback to execute when data arrives on a socket.
Changes between FreeRTOS V9.0.1 and FreeRTOS V10.0.0:
The FreeRTOS kernel is now MIT licensed: https://www.FreeRTOS.org/license
New Features and components:
+ Stream Buffers - see https://www.FreeRTOS.org/RTOS-stream-buffer-example.html
+ Message Buffers - see https://www.FreeRTOS.org//RTOS-message-buffer-example.html
+ Move FreeRTOS+TCP into the main repository, along with the basic Win32
TCP demo FreeRTOS_Plus_TCP_Minimal_Windows_Simulator.
New ports or demos:
+ Added demo for TI SimpleLink CC3220 MCU.
+ Added MPU and non MPU projects for Microchip CEC and MEC 17xx and 51xx
MCUs.
+ Added CORTEX_MPU_Static_Simulator_Keil_GCC demo to test static allocation
in the MPU port.
Fixes or enhancements:
+ Cortex-M ports push additional register prior to calling
vTaskSwitchContext to ensure 8-byte alignment is maintained. Only
important if a user defined tick hook function performs an operation that
requires 8-byte alignment.
+ Optimisations to the implementation of the standard tickless idle mode on
Cortex-M devices.
+ Improvements to the Win32 port including using higher priority threads.
+ Ensure interrupt stack alignment on PIC32 ports.
+ Updated GCC TriCore port to build with later compiler versions.
+ Update mpu_wrappers.c to support static allocation.
+ The uxNumberOfItems member of List_t is now volatile - solving an issue
when the IAR compiler was used with maximum optimization.
+ Introduced configRECORD_STACK_HIGH_ADDRESS. When set to 1 the stack start
address is saved into each task's TCB (assuming stack grows down).
+ Introduced configINCLUDE_FREERTOS_TASK_C_ADDITIONS_H to allow user defined
functionality, and user defined initialisation, to be added to FreeRTOS's
tasks.c source file. When configINCLUDE_FREERTOS_TASK_C_ADDITIONS_H is
set to 1 a user provided header file called freertos_task_c_additions.h
will be included at the bottom of tasks.c. Functions defined in that
header file can call freertos_tasks_c_additions_init(), which in turn
calls a macro called FREERTOS_TASKS_C_ADDITIONS_INIT(), if it is defined.
FREERTOS_TASKS_C_ADDITIONS_INIT() can be defined in FreeRTOSConfig.h.
+ Introduced configPRE_SUPPRESS_TICKS_AND_SLEEP_PROCESSING( x ) which can be
defined by a user in FreeRTOSConfig.h. The macro is called before
assessing whether to enter tickless idle mode or not. If the macro sets
x to zero then tickless idle mode will not be entered. This allows users
to abort tickless idle mode entry before the tickless idle function is
even called - previously it was only possible to abort from within the
tickless idle function itself.
+ Added configPRINTF(), which can be defined by users to allow all libraries
to use the same print formatter.
+ Introduced configMAX() and configMIN() macros which default to standard
max( x, y ) and min( x, y ) macro behaviour, but can be overridden if the
application writer defines the same macros in FreeRTOSConfig.h.
+ Corrected the definition of StaticTask_t in the case where
INCLUDE_xTaskAbortDelay is set to 1.
+ Introduced configTIMER_SERVICE_TASK_NAME and configIDLE_TASK_NAME, both of
which can be defined to strings in FreeRTOSConfig.h to change the default
names of the timer service and idle tasks respectively.
+ Only fill the stack of a newly created task with a known value if stack
checking, or high water mark checking/viewing, is in use - removing the
dependency on memset() in other cases.
+ Introduced xTaskCreateRestrictedStatic() so static allocation can be used
with the MPU.
+ Ensure suspended tasks cannot be unsuspended by a received task
notification.
+ Fix race condition in vTaskSetTimeOutState().
+ Updated trace recorder files to the latest version.
Changes since FreeRTOS V9.0.0:
+ Priority dis-inheritance behaviour has been enhanced in the case where a
task that attempted to take a mutex that was held by a lower priority task
timed out before it was able to obtain the mutex (causing the task that
holds the mutex to have its priority raised, then lowered again, in
accordance with the priority inheritance protocol).
+ Split the overloaded xQueueGenericReceive() function into three separate
dedicated functions.
+ Allow the default human readable text names given to the Idle and Timer
tasks to be overridden by defining the configIDLE_TASK_NAME and
configTIMER_SERVICE_TASK_NAME definitions respectively in FreeRTOSConfig.h.
+ Introduced configINITIAL_TICK_COUNT to allow the tick count to take a
value of than than 0 when the system boots. This can be useful for
testing purposes - although setting configUSE_16_BIT_TICKS to 1 can also
be used to test frequent tick overflows.
+ Ensure the Cortex-M SysTick count is cleared to zero before starting the
first task.
+ Add configASSERT() into ARM Cortex-M ports to check the number of priority
bit settings.
+ Clear the 'control' register before starting ARM Cortex-M4F ports in case
the FPU is used before the scheduler is started. This just saves a few
bytes on the main stack as it prevents space being left for a later save
of FPU registers.
+ Added xSemaphoreGetMutexHolderFromISR().
+ Corrected use of portNVIC_PENDSVSET to portNVIC_PENDSVSET_BIT in MPU ports.
+ Introduced configSTACK_DEPTH_TYPE to allow users to change the type used
to specify the stack size when using xTaskCreate(). For historic reasons,
when FreeRTOS was only used on small MCUs, the type was set to uint16_t,
but that can be too restrictive when FreeRTOS is used on larger
processors. configSTACK_DEPTH_TYPE defaults to uint16_t.
xTaskCreateStatic(), being a newer function, used a uint32_t.
+ Increase the priority of the Windows threads used by the Win32 port. As
all the threads run on the same core, and the threads run with very high
priority, there is a risk that the host will become unresponsive, so also
prevent the Windows port executing on single core hosts.
Changes between FreeRTOS V9.0.0 and FreeRTOS V9.0.0rc2 released May 25 2016:
See https://www.FreeRTOS.org/FreeRTOS-V9.html
RTOS kernel updates:
+ The prototype of the new xTaskCreateStatic() API function was modified to
remove a parameter and improve compatibility with other new
"CreateStatic()" API functions. The stack size parameter in
xTaskCreateStatic() is now uint32_t, which changes the prototype of the
callback functions. See the following URL:
https://www.FreeRTOS.org/xTaskCreateStatic.html
+ GCC ARM Cortex-A port: Introduced the configUSE_TASK_FPU_SUPPORT
constant. When configUSE_TASK_FPU_SUPPORT is set to 2 every task is
automatically given a floating point (FPU) context.
+ GCC ARM Cortex-A port: It is now possible to automatically save and
restore all floating point (FPU) registers on entry to each potentially
nested interrupt by defining vApplicationFPUSafeIRQHandler() instead of
vApplicationIRQHandler().
+ All ARM Cortex-M3/4F/7 ports: Clear the least significant bit of the task
entry address placed onto the stack of a task when the task is created for
strict compliance with the ARM Cortex-M3/4/7 architecture documentation
(no noticeable effect unless using the QMEU emulator).
+ Added GCC and Keil ARM Cortex-M4F MPU ports - previously the MPU was only
supported on ARM Cortex-M3.
+ ARM Cortex-M3/4F MPU ports: Update to fully support the FreeRTOS V9.0.0
API (other than static object creation) and added the
FreeRTOS/Demo/CORTEX_MPU_Simulator_Keil_GCC demo application to
demonstrate how to use the updated MPU port.
+ All ARM Cortex-M3/4F/7 ports: Add additional barrier instructions to the
default low power tickless implementation.
+ All ARM Cortex-M0 ports: Prevent an item being left on the stack of the
first task that executes.
+ Win32 ports: Reduce the amount of stack used and change the way Windows
threads are deleted to increase the maximum execution time.
+ Add an ARM Cortex-M4F port for the MikroC compiler. Ensure to read the
documentation page for this port before use.
+ MPS430X IAR port: Update to be compatible with the latest EW430 tools
release.
+ IAR32 GCC port: Correct vPortExitCritical() when
configMAX_API_CALL_INTERRUPT_PRIORITY == portMAX_PRIORITY.
+ For consistency vTaskGetTaskInfo() now has the alias vTaskGetInfo(),
xTaskGetTaskHandle() now has the alias xTaskGetHandle() and
pcQueueGetQueueName() now has an alias pcQueueGetName().
+ Fix various errors in comments and compiler warnings.
Demo application updates:
+ Update Atmel Studio projects to use Atmel Studio 7.
+ Update Xilinx SDK projects to use the 2016.1 version of the SDK.
+ Remove dependency on legacy IO libraries from the PIC32 demos.
+ Move the Xilinx UltraScale Cortex-R5 demo into the main distribution.
+ Update the MSP432 libraries to the latest version.
+ Add Microchip CEC1302 (ARM Cortex-M4F) demos for GCC, Keil and MikroC
compilers.
+ Move the Atmel SAMA5D2 demo into the main distribution.
Changes between FreeRTOS V9.0.0rc1 and FreeRTOS V9.0.0rc2 (release candidate 2)
released March 30 2016:
NOTE - See https://www.FreeRTOS.org/FreeRTOS-V9.html for details
+ The functions that create RTOS objects using static memory allocation have
been simplified and will not revert to using dynamic allocation if a
buffer is passed into a function as NULL.
+ Introduced the configSUPPORT_DYNAMIC_ALLOCATION configuration constant to
allow a FreeRTOS application to be built without a heap even being being
defined. The Win32 example located in the
/FreeRTOS/demo/WIN32-MSVC-Static-Allocation-Only directory is provided as
a reference for projects that do not include a FreeRTOS heap.
+ Minor run-time optimisations.
+ Two new low power tickless implementations that target Silicon Labs EFM32
microcontrollers.
+ Addition of the xTimerGetPeriod() and xTimerGetExpireTime() API functions.
Changes between FreeRTOS V8.2.3 and FreeRTOS V9.0.0rc1 (release candidate 1)
released February 19 2016:
RTOS Kernel Updates:
+ Major new feature - tasks, semaphores, queues, timers and event groups can