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Tidy up Win32 port layer - include addition of new variable that prevents recursive attempts to obtain a mutex when the trace recorder is used inside an interrupt.

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pull/4/head
Richard Barry 6 years ago
parent b1e35551c4
commit 5352cb4f45
1 changed files with 76 additions and 57 deletions
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133
FreeRTOS/Source/portable/MSVC-MingW/port.c
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@ -68,6 +68,15 @@ static void prvProcessSimulatedInterrupts( void );
static uint32_t prvProcessYieldInterrupt( void );
static uint32_t prvProcessTickInterrupt( void );
/*
* Exiting a critical section will cause the calling task to block on yield
* event to wait for an interrupt to process if an interrupt was pended while
* inside the critical section. This variable protects against a recursive
* attempt to obtain pvInterruptEventMutex if a critical section is used inside
* an interrupt handler itself.
*/
static volatile BaseType_t xInsideInterrupt = pdFALSE;
/*
* Called when the process exits to let Windows know the high timer resolution
* is no longer required.
@ -169,20 +178,22 @@ TIMECAPS xTimeCaps;
configASSERT( xPortRunning );
/* Can't proceed if in a critical section as pvInterruptEventMutex won't
be available. */
WaitForSingleObject( pvInterruptEventMutex, INFINITE );
/* The timer has expired, generate the simulated tick event. */
ulPendingInterrupts |= ( 1 << portINTERRUPT_TICK );
/* The interrupt is now pending - notify the simulated interrupt
handler thread. */
if( ulCriticalNesting == portNO_CRITICAL_NESTING )
{
SetEvent( pvInterruptEvent );
}
handler thread. Must be outside of a critical section to get here so
the handler thread can execute immediately pvInterruptEventMutex is
released. */
configASSERT( ulCriticalNesting == 0UL );
SetEvent( pvInterruptEvent );
/* Give back the mutex so the simulated interrupt handler unblocks
and can access the interrupt handler variables. */
and can access the interrupt handler variables. */
ReleaseMutex( pvInterruptEventMutex );
}
@ -341,6 +352,7 @@ SYSTEM_INFO xSystemInfo;
static uint32_t prvProcessYieldInterrupt( void )
{
/* Always return true as this is a yield. */
return pdTRUE;
}
/*-----------------------------------------------------------*/
@ -379,8 +391,16 @@ CONTEXT xContext;
for(;;)
{
xInsideInterrupt = pdFALSE;
WaitForMultipleObjects( sizeof( pvObjectList ) / sizeof( void * ), pvObjectList, TRUE, INFINITE );
/* /* Cannot be in a critical section to get here. Tasks that exist a
critical section will block on a yield mutex to wait for an interrupt to
process if an interrupt was set pending while the task was inside the
critical section. xInsideInterrupt prevents interrupts that contain
critical sections from doing the same. */
xInsideInterrupt = pdTRUE;
/* Used to indicate whether the simulated interrupt processing has
necessitated a context switch to another task/thread. */
ulSwitchRequired = pdFALSE;
@ -390,14 +410,16 @@ CONTEXT xContext;
for( i = 0; i < portMAX_INTERRUPTS; i++ )
{
/* Is the simulated interrupt pending? */
if( ulPendingInterrupts & ( 1UL << i ) )
if( ( ulPendingInterrupts & ( 1UL << i ) ) != 0 )
{
/* Is a handler installed? */
if( ulIsrHandler[ i ] != NULL )
{
/* Run the actual handler. */
/* Run the actual handler. Handlers return pdTRUE if they
necessitate a context switch. */
if( ulIsrHandler[ i ]() != pdFALSE )
{
/* A bit mask is used purely to help debugging. */
ulSwitchRequired |= ( 1 << i );
}
}
@ -420,7 +442,15 @@ CONTEXT xContext;
that is already in the running state. */
if( pvOldCurrentTCB != pxCurrentTCB )
{
/* Suspend the old thread. */
/* Suspend the old thread. In the cases where the (simulated)
interrupt is asynchronous (tick event swapping a task out rather
than a task blocking or yielding) it doesn't matter if the
'suspend' operation doesn't take effect immediately - if it
doesn't it would just be like the interrupt occurring slightly
later. In cases where the yield was caused by a task blocking
or yielding then the task will block on a yield event after the
yield operation in case the 'suspend' operation doesn't take
effect immediately. */
pxThreadState = ( ThreadState_t *) *( ( size_t * ) pvOldCurrentTCB );
SuspendThread( pxThreadState->pvThread );
@ -451,7 +481,9 @@ CONTEXT xContext;
(to ensure it does not continue running after the call to
SuspendThread() above as SuspendThread() is asynchronous).
Signal the event to ensure the thread can proceed now it is
valid for it to do so. */
valid for it to do so. Signaling the event is benign in the case that
the task was switched out asynchronously by an interrupt as the event
is reset before the task blocks on it. */
pxThreadState = ( ThreadState_t * ) ( *( size_t *) pxCurrentTCB );
SetEvent( pxThreadState->pvYieldEvent );
ReleaseMutex( pvInterruptEventMutex );
@ -527,7 +559,7 @@ uint32_t ulErrorCode;
/* This is called from a critical section, which must be exited before the
thread stops. */
taskEXIT_CRITICAL();
CloseHandle( pxThreadState->pvYieldEvent );
ExitThread( 0 );
}
/*-----------------------------------------------------------*/
@ -546,39 +578,32 @@ ThreadState_t *pxThreadState = ( ThreadState_t *) *( ( size_t * ) pxCurrentTCB )
if( ( ulInterruptNumber < portMAX_INTERRUPTS ) && ( pvInterruptEventMutex != NULL ) )
{
/* Yield interrupts are processed even when critical nesting is
non-zero. */
WaitForSingleObject( pvInterruptEventMutex, INFINITE );
ulPendingInterrupts |= ( 1 << ulInterruptNumber );
/* The simulated interrupt is now held pending, but don't actually
process it yet if this call is within a critical section. It is
possible for this to be in a critical section as calls to wait for
mutexes are accumulative. */
mutexes are accumulative. If in a critical section then the event
will get set when the critical section nesting count is wound back
down to zero. */
if( ulCriticalNesting == portNO_CRITICAL_NESTING )
{
SetEvent( pvInterruptEvent );
if( ulInterruptNumber == portINTERRUPT_YIELD )
{
/* Going to wait for an event - make sure the event is not already
signaled. */
ResetEvent( pxThreadState->pvYieldEvent );
}
/* Going to wait for an event - make sure the event is not already
signaled. */
ResetEvent( pxThreadState->pvYieldEvent );
}
ReleaseMutex( pvInterruptEventMutex );
if( ulCriticalNesting == portNO_CRITICAL_NESTING )
{
if( ulInterruptNumber == portINTERRUPT_YIELD )
{
/* The task was yielding so will be suspended however the
SuspendThread() function is asynchronous so this event is used to
prevent the task executing further if SuspendThread() does not take
effect immediately. */
WaitForSingleObject( pxThreadState->pvYieldEvent, INFINITE );
}
/* An interrupt was pended so ensure to block to alow it to
execute. In most cases the (simulated) interrupt will have
executed before the next line is reached - so this is just to make
sure. */
WaitForSingleObject( pxThreadState->pvYieldEvent, INFINITE );
}
}
}
@ -626,10 +651,12 @@ int32_t lMutexNeedsReleasing, lWaitForYield = pdFALSE;
if( ulCriticalNesting > portNO_CRITICAL_NESTING )
{
if( ulCriticalNesting == ( portNO_CRITICAL_NESTING + 1 ) )
{
ulCriticalNesting--;
ulCriticalNesting--;
/* Don't need to wait for any pending interrupts to execute if the
critical section was exited from inside an interrupt. */
if( ( ulCriticalNesting == portNO_CRITICAL_NESTING ) && ( xInsideInterrupt == pdFALSE ) )
{
/* Were any interrupts set to pending while interrupts were
(simulated) disabled? */
if( ulPendingInterrupts != 0UL )
@ -637,37 +664,29 @@ int32_t lMutexNeedsReleasing, lWaitForYield = pdFALSE;
ThreadState_t *pxThreadState = ( ThreadState_t *) *( ( size_t * ) pxCurrentTCB );
configASSERT( xPortRunning );
SetEvent( pvInterruptEvent );
if( ulPendingInterrupts != 0 )
{
/* Going to wait for an event - make sure the event is not already
signaled. */
ResetEvent( pxThreadState->pvYieldEvent );
lWaitForYield = pdTRUE;
}
/* The interrupt won't actually executed until
pvInterruptEventMutex is released as it waits on both
pvInterruptEventMutex and pvInterruptEvent.
pvInterruptEvent is only set when the simulated
interrupt is pendeded if the interrupt is pended
from outside a critical section - hence it is set
here. */
SetEvent( pvInterruptEvent );
/* The calling task is going to wait for an event to ensure the
interrupt that is pending executes immediately after the
critical section is exited - so make sure the event is not
already signaled. */
ResetEvent( pxThreadState->pvYieldEvent );
lWaitForYield = pdTRUE;
/* Mutex will be released now, so does not require releasing
on function exit. */
/* Mutex will be released now so the (simulated) interrupt can
execute, so does not require releasing on function exit. */
lMutexNeedsReleasing = pdFALSE;
ReleaseMutex( pvInterruptEventMutex );
if( lWaitForYield != pdFALSE )
{
/* The task was yielding so will be suspended however the
SuspendThread() function is asynchronous so this event is
used to prevent the task executing further if
SuspendThread() does not take effect immediately. */
WaitForSingleObject( pxThreadState->pvYieldEvent, INFINITE );
}
WaitForSingleObject( pxThreadState->pvYieldEvent, INFINITE );
}
}
else
{
/* Tick interrupts will still not be processed as the critical
nesting depth will not be zero. */
ulCriticalNesting--;
}
}
if( pvInterruptEventMutex != NULL )

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