This change removes the FreeRTOS System Calls (aka MPU wrappers) for the
following kernel APIs:
- xTaskCreateRestricted
- xTaskCreateRestrictedStatic
- vTaskAllocateMPURegions
A system call allows an unprivileged task to execute a kernel API which
is otherwise accessible to privileged software only. The above 3 APIs
can create a new task with a different MPU configuration or alter the
MPU configuration of an existing task. This an be (mis)used by an
unprivileged task to grant itself access to a region which it does not
have access to.
Removing the system calls for these APIs ensures that an unprivileged
task cannot execute this APIs. If an unprivileged task attempts to
execute any of these API, it will result in a Memory Fault.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
Critical sections in FreeRTOS are implemented using the following two
functions:
void vPortEnterCritical( void )
{
portDISABLE_INTERRUPTS();
uxCriticalNesting++;
}
void vPortExitCritical( void )
{
uxCriticalNesting--;
if( uxCriticalNesting == 0 )
{
portENABLE_INTERRUPTS();
}
}
uxCriticalNesting is initialized to a large value at the start and set
to zero when the scheduler is started (xPortStartScheduler). As a
result, before the scheduler is started, a pair of enter/exit critical
section will leave the interrupts disabled because uxCriticalNesting
will not reach zero in the vPortExitCritical function. This is done to
ensure that the interrupts remain disabled from the time first FreeRTOS
API is called to the time when the scheduler is started. The scheduler
starting code is expected to enure that interrupts are enabled before
the first task starts executing.
Cortex-M33 ports were not enabling interrupts before starting the first
task and as a result, the first task was started with interrupts
disabled. This PR fixes the issue by ensuring that interrupts are
enabled before the first task is started.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
* Xtensa: fix the coproc_area incorrect issue
foss-xtensa/amazon-freertos#2 mentioned a issue:
1.
In function pxPortInitialiseStack(StackType_t *pxTopOfStack....)
p = (uint32_t *)(((uint32_t) pxTopOfStack - XT_CP_SIZE) & ~0xf);
In function prvInitialiseNewTask (file: task.c)
pxTopOfStack = (pxStack + (ulStackDepth - 1)) & (~portBYTE_ALIGNMENT_MASK)
So the co-processor area is at
p = (uint32_t *)(((uint32_t)((pxStack + (ulStackDepth - 1)) & (~portBYTE_ALIGNMENT_MASK)) - XT_CP_SIZE) & ~0xf);
2.
In function vPortStoreTaskMPUSettings( .... , StackType_t pxBottomOfStack ...)
xMPUSettings->coproc_area = (StackType_t)((((uint32_t)(pxBottomOfStack + usStackDepth - 1)) - XT_CP_SIZE) & ~0xf);
pxBottomOfStack = pxStack
=> xMPUSettings->coproc_area = (StackType_t*)((((uint32_t)(pxStack+ ulStackDepth - 1)) - XT_CP_SIZE ) & ~0xf);
The p is coproc_area that should be equal to xMPUSettings->coproc_area.
For example, assume pxStack is 0xa0000000, ulStackDepth is 0x2000,
portBYTE_ALIGNMENT_MASK is 0x7f, XT_CP_SIZE is 0x100.
The p = (uint32_t)(((uint32_t)((pxStack + (ulStackDepth - 1)) & (~portBYTE_ALIGNMENT_MASK)) - XT_CP_SIZE) & ~0xf)
= 0xa0001e80
The xMPUSettings->coproc_area = (StackType_t)((((uint32_t)(pxStack+ usStackDepth - 1)) - XT_CP_SIZE ) & ~0xf)
= 0xa0001ef0
Obviously, the p is not equal to the xMPUSettings->coproc_area, which will cause context switching error.
Signed-off-by: magicse7en <magicse7en@outlook.com>
* Update port.c
Co-authored-by: Carl Lundin <53273776+lundinc2@users.noreply.github.com>
In function pxPortInitialiseStack of port.c:
sp = ( StackType_t * ) ( ( ( UBaseType_t ) ( pxTopOfStack + 1 ) - XT_CP_SIZE - XT_STK_FRMSZ ) & ~0xf );
We assume XT_CP_SIZE is 0xE4, XT_STK_FRMSZ is 0xA0, pxTopOfStack is 0xA0000000, sp is 0x9FFFFE80.
From port.c, we know the frame->a1 as below:
frame->a1 = ( UBaseType_t ) sp + XT_STK_FRMSZ; /* physical top of stack frame */
So frame->a1 is 0x9FFFFF20. Therefore the interrupt stack frame range is 0x9FFFFE80 ~ 0x9FFFFF20.
The coproc_area is: p = ( uint32_t * ) ( ( ( uint32_t ) pxTopOfStack - XT_CP_SIZE ) & ~0xf );
So its value is 0x9FFFFF10. Obviously, the interrupt stack frame overlaps the coproc_area.
Co-authored-by: Carl Lundin <53273776+lundinc2@users.noreply.github.com>
This PR:
Changes the INCLUDE_vTaskDelayUntil compile time constant to INCLUDE_xTaskDelayUntil.
Updates FreeRTOS.h to ensure backward compatibility for projects that already have INCLUDE_vTaskDelayUntil defined.
Updates the MPU prototypes, wrapper and implementation to use the updated xTaskDelayUntil() function.
Tests to be checked into the FreeRTOS/FreeRTOS repository after this PR.
* Renamed old port to ESP_IDF_V3
* Update ESP32 port files to support IDF v4.2.
* Add changes required to support ESP32-S2
Co-authored-by: Shubham Kulkarni <shubham.kulkarni@espressif.com>
* Posix: Fix no task switching issue if a task ended
When the main function of a task exits, no task switching happened.
This is because all the remaining tasks are waiting on the condition
variable. The fix is to trigger a task switch and mark the exiting
task as "Dying" to be suspened and exited properly from the scheduler.
* Posix: Assert and stop if the Task function returned
* Posix: just assert if a task returned from its main function
Co-authored-by: alfred gedeon <alfred2g@hotmail.com>
* Posix: Free Idle task resources after ending the scheduler
In case of using Posix simulator and ending the scheduler, it does
not free the resources allocated by the idle task. This
causes the memory checkers (Valgrind, Address Sanitizers, ..) to
complain.
* Posix: Free the condition variable memory in the correct place
In case of deleting a task from another task, the deletion happens
immediately and the thread is canceled but the memory allocated by
the task condition variable is not freed. This causes the memory
checkers (Valgrind, Address sanitizers, ..) to complain.
* Posix: End Timer thread and free its resources after ending the scheduler
* Maintenance: Add readme.txt in each Renesas RX folder to show recomended port
* Update readme.txt in each Renesas RX folder regarding to Notes *1 and *2 (both are RX100 port)
* Style: fix some broken/redirect links
* Fix: atmel url
* Fix microchip typo
* Fix url links
* Fix shortcut link
* Comment: fix line wrapping
* Style: fix line wrapping to 80 chars
* Add now microchip beside Atmel
* Fix link in History
* Add Now Microchip before Atmel link
* Comment: add *
* Change vPortSetupTimerInterrupt in order to have 64bits access on rv64
* Support RV32E - RISC-V architecture (GCC)
Signed-off-by: Emmanuel Puerto <emmanuel.puerto@sifive.com>
* Support FPU - RISC-V architecture (GCC)
Signed-off-by: Emmanuel Puerto <emmanuel.puerto@sifive.com>
* Fix interrupt managment and FPU initialization
* Synopsys Port: Adding support to Synopsys ARC v1 series cores
ARC v1 cores include ARC605, ARC610d, and ARC710d
Signed-off-by: Yuguo Zou <yuguo.zou@synopsys.com>
* Synopsys ARC v1 port: run uncrustify to fix code style
Signed-off-by: Yuguo Zou <yuguo.zou@synopsys.com>
* Synopsys port: modify license headers, change copyright only
Signed-off-by: Yuguo Zou <yuguo.zou@synopsys.com>
* Add RX200 GCC compiler
Signed-off-by: Dinh Van Nam <vannam.dinh.xt@renesas.com>
* Update GCC compiler for:
* RX600v2
* RX600
* RX100
Signed-off-by: Dinh Van Nam <vannam.dinh.xt@renesas.com>
* Use configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H flag
* Use configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H flag RX100, RX200
Co-authored-by: Dinh Van Nam <vannam.dinh.xt@renesas.com>
* Style: make freertos.org = FreeRTOS.org also add https
* Style: Fix freertos into FreeRTOS
* Style: Fix freertos into FreeRTOS
Co-authored-by: Alfred Gedeon <gedeonag@amazon.com>
* Style: Change FreeRTOS websites in comments
* Style: Change freertos to FreeRTOS in comments
* Style: Remove broken link
Co-authored-by: Alfred Gedeon <gedeonag@amazon.com>
* Update port.c
I discovered a very snicky and tricky race condition scenario when integrating tracealyzer code into our project.
A little background on CortexR5 : When the IRQ line (comming from the interrupt controller, to which every peripheral IRQ lines connect) of the processor rises and the IRQ Enable bit in the status register of the CPU permits it, the CPU traps into interrupt mode. Several things happen. First, the CPU finishes the instruction it was performing. Second, it places the content of the CPSR register into the SPSR_irq register. And third, the mode of the CPU is changed to IRQ_Mode and /!\ THE IRQ ENABLE BIT IN CPSR_irq IS AUTOMATICALLY CLEARED /!\. The reason is to ensure that upon landing into IRQ code, we find ourselves automatically in a critical section because we cannot be interrupted again because the bit is cleared. The programmer can, if he wants, re-enable IRQs inside IRQ code itself to allow interrupt nesting. But it has to be wanted and meditated.
Now, inside portASM.S, at the end of 'FreeRTOS_IRQ_Handler' assembly function, a call to 'vTaskSwitchContextConst' is made if the variable 'ulPortYieldRequired' was set by someone while executing the interrupt. Before branching to that function, a 'CPSID i' instruction was placed to ensure that interrupts are disabled in case someone re-enabled it. Inside 'vTaskSwitchContext', there is the macro 'traceTASK_SWITCHED_OUT' that gets populated when tracing is enabled.
The bug is right there.. If the macro is populated and inside that macro there is a matching call to 'ulPortSetInterruptMask' and 'vPortClearInterruptMask', a race condition can occure is there is a OS Tick timer interrupt waiting at the interrupt controller's door. Upon calling 'vTaskSwitchContext', the interrupts are not masked in the interrupt controller, the only barrier against the CPU servicing that tick interrupt while already performing the function is that the IRQ Enable bit cleared. 'ulPortSetInterruptMask'
does what's its supposed to do, but doesn't take into account the IRQ Enable bit in CPSR. Wheter or not the bit was cleared, the function sets it at the end. When calling the matching 'vPortClearInterruptMask', the function clears the interrupt mask in the interrupt controller. Because the IRQ Enable bit (that was cleared) has been set no matter what in 'ulPortSetInterruptMask', the CPU services the OS Tick Interrupt right away.
The bug is there : instead of completing the 'vTaskSwitchContext' function, the CPU re-enters the switch context path right after 'traceTASK_SWITCHED_OUT' thus corrupting the CPU state and eventually triggering either an undefined instruction, data or instruction abort.
* Update port.c
Error on my part, this is the right inline asm code to retreive CPSR register
* Update port.c
Forgot an * while writing comment..
The TEX, Shareable (S), Cacheable (C) and Bufferable (B) bits define
the memory type, and where necessary the cacheable and shareable
properties of the memory region.
The default values for these bits, as configured in our MPU ports, are
sometimes not suitable for application. One such example is when the MCU
has a cache, the application writer may not want to mark the memory as
shareable to avoid disabling the cache. This change allows the
application writer to override default vales for TEX, S C and B bits for
Flash and RAM in their FreeRTOSConfig.h. The following two new
configurations are introduced:
- configTEX_S_C_B_FLASH
- configTEX_S_C_B_SRAM
If undefined, the default values for the above configurations are
TEX=000, S=1, C=1, B=1. This ensures backward compatibility.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
* Removed TICK_stop() macro from portable/GCC/{AVR_AVRDx, AVR_Mega0}/porthardware.h because it is not used anywhere.
* Updated indentation in portable/GCC/{AVR_AVRDx, AVR_Mega0}/* files.
* Added portable/IAR/{AVR_AVRDx, AVR_Mega0 folders.
The expected behaviour of portIS_PRIVILEGED is:
- return 0 if the processor is not running privileged.
- return 1 if the processor is running privileged.
Some TI ports do not return 1 when the processor is running privileged
causing the following check to fail: if( xRunningPrivileged != pdTRUE )
This commit change the check to: if( xRunningPrivileged == pdFALSE ). It
ensures that the check is successful even on the ports which return incorrect
value from portIS_PRIVILEGED when the processor is running privileged.
See https://forums.freertos.org/t/kernel-bug-nested-mpu-wrapper-calls-generate-an-exception/10391
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
configSYSTICK_CLOCK_HZ should be used to configure SysTick to support
the use case when the clock for SysTick timer is scaled from the main
CPU clock.
configSYSTICK_CLOCK_HZ is defined to configCPU_CLOCK_HZ when it is not
defined in FreeRTOSConfig.h.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
ARMv7-M supports 8 or 16 MPU regions. FreeRTOS Cortex-M4 MPU ports so
far assumed 8 regions. This change adds support for 16 MPU regions. The
hardware with 16 MPU regions must define configTOTAL_MPU_REGIONS to 16
in their FreeRTOSConfig.h.
If left undefined, it defaults to 8 for backward compatibility.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
Update BSP APIs to latest version
Remove unused macro which could have caused warnings
(Code Style) Manually align some macros
Signed-off-by: Yuguo Zou <yuguo.zou@synopsys.com>
These definitions were not useful because the corresponding mapping was
removed from mpu_wrappers.h earlier.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
The reason for the change is that the register is called System Handler
Priority Register 3 (SHPR3).
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
Some of the privileged symbols were not being placed in their respective
sections. This commit addresses those and places them in
privileged_functions or privileged_data section.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
If xTaskCreate API is used to create a task, the task's stack is
allocated on heap using pvPortMalloc. This places the task's stack
in the privileged data section, if the heap is placed in the
privileged data section.
We use a separate MPU region to grant a task access to its stack.
If the task's stack is in the privileged data section, this results in
overlapping MPU regions as privileged data section is already protected
using a separate MPU region. ARMv8-M does not allow overlapping MPU
regions and this results in a fault. This commit ensures to not use a
separate MPU region for the task's stack if it lies within the
privileged data section.
Note that if the heap memory is placed in the privileged data section,
the xTaskCreate API cannot be used to create an unprivileged task as
the task's stack will be in the privileged data section and the task
won't have access to it. xTaskCreateRestricted and
xTaskCreateRestrictedStatic API should be used to create unprivileged
tasks.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
When Link Time Optimization (LTO) is enabled, some of the LDR
instructions result in out of range access. The reason is that the
default generated literal pool is too far and not within the permissible
range of 4K.
This commit adds LTORG assembly instructions at required places to
ensure that access to literals remain in the permissible range of 4K.
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
Refer to https://www.freertos.org/a00133.html.
The issue with the implementation is that, if only stop kernel tick the program will keep executing current task.
The desired behavior is to at least return/jump to the next instruction after vTaskStartScheduler().
Signed-off-by: Yuhui Zheng <10982575+yuhui-zheng@users.noreply.github.com>
* fix: CLEAR MIE BIT IN INITIAL RISC-V MSTATUS VALUE
The MIE bit in the RISC-V MSTATUS register is used to globally enable
or disable interrupts. It is copied into the MPIE bit and cleared
on entry to an interrupt, and then copied back from the MPIE bit on
exit from an interrupt.
When a task is created it is given an initial MSTATUS value that is
derived from the current MSTATUS value with the MPIE bit force to 1,
but the MIE bit is not forced into any state. This change forces
the MIE bit to 0 (interrupts disabled).
Why:
If a task is created before the scheduler is started the MIE bit
will happen to be 0 (interrupts disabled), which is fine. If a
task is created after the scheduler has been started the MIE bit
is set (interrupts enabled), causing interrupts to unintentionally
become enabled inside the interrupt in which the task is first
moved to the running state - effectively breaking a critical
section which in turn could cause a crash if enabling interrupts
causes interrupts to nest. It is only an issue when starting a
newly created task that was created after the scheduler was started.
Related Issues:
https://forums.freertos.org/t/risc-v-port-pxportinitialisestack-issue-about-mstatus-value-onto-the-stack/9622
Co-authored-by: Cobus van Eeden <35851496+cobusve@users.noreply.github.com>
Enabling Link Time Optimization (LTO) causes some of the functions used
in assembly to be incorrectly stripped off, resulting in linker error.
To avoid this, these functions are marked with portDONT_DISCARD macro,
definition of which is port specific. This commit adds the definition
of portDONT_DISCARD for ARMv7-M ports.
Signed-off-by: Gaurav Aggarwal
Problem Description
-------------------
The current flash organization in ARMv7-M MPU ports looks as follows:
__FLASH_segment_start__ ------->+-----------+<----- __FLASH_segment_start__
| Vector |
| Table |
| + |
| Kernel |
| Code |
+-----------+<----- __privileged_functions_end__
| |
| |
| |
| Other |
| Code |
| |
| |
| |
__FLASH_segment_end__ ------>+-----------+
The FreeRTOS kernel sets up the following MPU regions:
* Unprivileged Code - __FLASH_segment_start__ to __FLASH_segment_end__.
* Privileged Code - __FLASH_segment_start__ to __privileged_functions_end__.
The above setup assumes that the FreeRTOS kernel code
(i.e. privileged_functions) is placed at the beginning of the flash and,
therefore, uses __FLASH_segment_start__ as the starting location of the
privileged code. This prevents a user from placing the FreeRTOS kernel
code outside of flash (say to an external RAM) and still have vector
table at the beginning of flash (which is many times a hardware
requirement).
Solution
--------
This commit addresses the above limitation by using a new variable
__privileged_functions_start__ as the starting location of the
privileged code. This enables users to place the FreeRTOS kernel code
wherever they choose.
The FreeRTOS kernel now sets up the following MPU regions:
* Unprivileged Code - __FLASH_segment_start__ to __FLASH_segment_end__.
* Privileged Code - __privileged_functions_start__ to __privileged_functions_end__.
As a result, a user can now place the kernel code to an external RAM. A
possible organization is:
Flash External RAM
+------------+ +-----------+<------ __privileged_functions_start__
| Vector | | |
| Table | | |
| | | |
__FLASH_segment_start__ ----->+------------+ | Kernel |
| | | Code |
| | | |
| | | |
| | | |
| Other | | |
| Code | +-----------+<------ __privileged_functions_end__
| |
| |
| |
__FLASH_segment_end__ ----->+------------+
Note that the above configuration places the vector table in an unmapped
region. This is okay because we enable the background region, and so the
vector table will still be accessible to the privileged code and not
accessible to the unprivileged code (vector table is only needed by the
privileged code).
Backward Compatibility
----------------------
The FreeRTOS kernel code now uses a new variable, namely
__privileged_functions_start__, which needs to be exported from linker
script to indicate the starting location of the privileged code. All of
our existing demos already export this variable and therefore, they will
continue to work.
If a user has created a project which does not export this variable,
they will get a linker error for unresolved symbol
__privileged_functions_start__. They need to export a variable
__privileged_functions_start__ with the value equal to
__FLASH_segment_start__.
Issue
-----
https://sourceforge.net/p/freertos/feature-requests/56/
Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
This is similar to the Windows port, allowing FreeRTOS kernel
applications to run as regular applications on Posix (Linux) systems.
You can use this in a 32-bit or 64-bit application (although there are
dynamic memory allocation trace points that do not support 64-bit
addresses).
Many of the same caveats of running an RTOS on a non-real-time system
apply, but this is still very useful for easy debugging/testing
applications in a simulated environment. In particular, it allows easy
use of tools such as valgrind.
You can call standard library functions from tasks but care must be
taken with any that internally take mutexes or block. This includes
malloc()/free() and many stdio functions (e.g., printf()).
Replacement malloc(), free(), realloc(), and calloc() functions are
provided which are safe. printf() needs to be called with a FreeRTOS
mutex help (or called from only a single task).
Each task is run in its own pthread, which makes debugging with
standard tools (such as GDB) easier backtraces for individual tasks
are available. Threads for non-running tasks are blocked in sigwait().
The stack for each task (thread) is allocated when the thread is
created, and the stack provided during task creation is not used. This
is so the stack has guard pages, to help with detecting stack
overflows.
Task switch is done by resuming the thread for the next task by
sending it the resume signal (SIGUSR1) and then suspending the current
thread.
The timer interrupt uses SIGALRM and care is taken to ensure that the
signal handler runs only on the thread for the current task.
The additional data needed per-thread is stored at the top on the
task's stack.
When a running task is being deleted, its thread is marked it as dying
so when we switch away from it it exits instead of suspending. This
ensures that even if the idle task doesn't run, threads are deleted
which allows for more threads to be created (if many tasks are being
created and deleted in rapid succession).
To further aid debugging, SIGINT (^C) is not blocked inside critical
sections. This allows it to be used break into GDB while in a critical
section. This means that care must be taken with any custom SIGINT
handlers as these are like NMIs.
This is somewhat inspired by an existing port by William Davy
(https://www.freertos.org/FreeRTOS-simulator-for-Linux.html) but it
takes a number of different approaches to make it switch tasks
reliableand there's little similarly with the original implementation.
- Critical sections block scheduling/"interrupts" by blocking signals
using pthread_sigmask(). This is more expensive than attempting to
use flags but works reliably and is analogous to the interrupt
enable/disable on real hardware.
- Care is take to ensure that the SIGALRM handler (for the timer tick)
is runnable only on the pthread for the running task. This makes
tasks switches more straight-forward and reliable as we can suspend
the thread while in the signal handler.
- Task switches save/restore the critical nesting on the stack.
- Only uses a single (SIGUSR1) signal which is ignored and thus GDB's
default signal handling options won't trap/print on this signal.
- Extra per-thread data is stored on the task's stack, making it
accessible in O(1) instead of performing a O(n) lookup of the array.
- Uses the task create/delete hooks in a similar way to the Windows
port, rather than overloading trace points.
xtensa_loadstore_handler.S uses _iram_end to prevent modification of IRAM
code. With the LoadStore exception handler in place, IRAM can also be
used for .bss and .data section. Hence the sanity check should be based
upon _iram_text_end and not _iram_end
sherryzhang
Cobus van Eeden
alfred gedeon
Gaurav-Aggarwal-AWS
David Chalco
filipgeorge
Carl Lundin
Jon Snow
magicse7en
RichardBarry
Joseph Julicher
Reda Maher
NoMaY (a user of Japan.RenesasRulz.com)
David Chalco
Emmanuel Puerto
YuguoWH
Ming Yue
Ravishankar Bhagavandas
Simon Beaudoin
m17336
DavidJurajdaNXP
Shubham Kulkarni
Alfred Gedeon
Yuhui Zheng
Phillip Stevens
David Vrabel
RichardBarry
Vladimir Umek
Sachin Parekh