len0rd/FreeRTOS-Kernel
1
0
Fork 0
mirror of https://github.com/FreeRTOS/FreeRTOS-Kernel.git synced 2025-06-05 20:09:05 -04:00
Code Issues Packages Projects Releases Wiki Activity

Xtensa: fix stack overlap coproc_area issue (#118)

Browse source 
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 commit is contained in:
magicse7en 2020-10-27 02:07:32 +08:00 committed by GitHub
parent f376c3bd71
commit b9748e50ea
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 45 additions and 40 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
portable/ThirdParty/XCC/Xtensa/port.c vendored
View file

@ -92,16 +92,19 @@ StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t px
{
StackType_t * sp, * tp;
XtExcFrame * frame;
#if XCHAL_CP_NUM > 0
uint32_t * p;
#endif
/* Create interrupt stack frame aligned to 16 byte boundary */
sp = (StackType_t *) (((UBaseType_t)(pxTopOfStack + 1) - XT_CP_SIZE - XT_STK_FRMSZ) & ~0xf);
sp = ( StackType_t * ) ( ( ( UBaseType_t ) pxTopOfStack - XT_CP_SIZE - XT_STK_FRMSZ ) & ~0xf );
/* Clear the entire frame (do not use memset() because we don't depend on C library) */
for( tp = sp; tp <= pxTopOfStack; ++tp )
{
*tp = 0;
}
frame = ( XtExcFrame * ) sp;
@ -129,10 +132,12 @@ StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t px
#if XCHAL_CP_NUM > 0
/* Init the coprocessor save area (see xtensa_context.h) */
/* No access to TCB here, so derive indirectly. Stack growth is top to bottom.
* //p = (uint32_t *) xMPUSettings->coproc_area;
*/
p = ( uint32_t * ) ( ( ( uint32_t ) pxTopOfStack - XT_CP_SIZE ) & ~0xf );
configASSERT( ( uint32_t ) p >= frame->a1 );
p[ 0 ] = 0;
p[ 1 ] = 0;
p[ 2 ] = ( ( ( uint32_t ) p ) + 12 + XCHAL_TOTAL_SA_ALIGN - 1 ) & -XCHAL_TOTAL_SA_ALIGN;