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ebbe2cf854
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>
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| .. | ||
| portable | ||
| port.c | ||
| portasm.h | ||
| ReadMe.txt | ||
This directory tree contains the master copy of the FreeeRTOS Cortex-M33 port. Do not use the files located here! These file are copied into separate FreeRTOS/Source/portable/[compiler]/ARM_CM33_NNN directories prior to each FreeRTOS release. If your Cortex-M33 application uses TrustZone then use the files from the FreeRTOS/Source/portable/[compiler]/ARM_CM33 directories. If your Cortex-M33 application does not use TrustZone then use the files from the FreeRTOS/Source/portable/[compiler]/ARM_CM33_NTZ directories.