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Xtensa: fix the coproc_area incorrect issue

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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>
This commit is contained in:
magicse7en 2020-08-12 22:36:06 +08:00
parent 61fc74f0c5
commit e2e9e7cbfc
1 changed files with 3 additions and 2 deletions
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5
portable/ThirdParty/XCC/Xtensa/port.c vendored
View file

@ -221,8 +221,9 @@ BaseType_t xPortSysTickHandler( void )
uint32_t ulStackDepth ) uint32_t ulStackDepth )
{ {
#if XCHAL_CP_NUM > 0 #if XCHAL_CP_NUM > 0
xMPUSettings->coproc_area = ( StackType_t * ) ( ( ( ( uint32_t ) ( pxBottomOfStack + ulStackDepth - 1 ) ) - XT_CP_SIZE ) & ~0xf ); xMPUSettings->coproc_area = ( StackType_t * ) ( ( uint32_t ) ( pxBottomOfStack + ulStackDepth - 1 ));
xMPUSettings->coproc_area = ( StackType_t * ) ( ( ( portPOINTER_SIZE_TYPE ) xMPUSettings->coproc_area ) & ( ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK ) ) );
xMPUSettings->coproc_area = ( Stacktype_t * ) ( ( ( uint32_t ) xMPUSettings->coproc_area - XT_CP_SIZE ) & ~0xf );
/* NOTE: we cannot initialize the coprocessor save area here because FreeRTOS is going to /* NOTE: we cannot initialize the coprocessor save area here because FreeRTOS is going to
* clear the stack area after we return. This is done in pxPortInitialiseStack(). * clear the stack area after we return. This is done in pxPortInitialiseStack().