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Xtensa: fix the coproc_area incorrect issue (#117)

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* 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>
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magicse7en 2020-10-27 02:47:21 +08:00 committed by GitHub
parent b9748e50ea
commit 82df39764a
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1 changed files with 12 additions and 9 deletions
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13
portable/ThirdParty/XCC/Xtensa/port.c vendored
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@ -212,16 +212,19 @@ BaseType_t xPortSysTickHandler( void )
* Used to set coprocessor area in stack. Current hack is to reuse MPU pointer for coprocessor area.
*/
#if portUSING_MPU_WRAPPERS
void vPortStoreTaskMPUSettings( xMPU_SETTINGS *xMPUSettings, const struct xMEMORY_REGION * const xRegions, StackType_t *pxBottomOfStack, uint32_t ulStackDepth )
void vPortStoreTaskMPUSettings( xMPU_SETTINGS * xMPUSettings,
const struct xMEMORY_REGION * const xRegions,
StackType_t * pxBottomOfStack,
uint32_t ulStackDepth )
{
#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
* clear the stack area after we return. This is done in pxPortInitialiseStack().
*/
#endif
}
#endif
#endif /* if portUSING_MPU_WRAPPERS */