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[Ada] vx21.07: stack-checking on ppc

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On VxWorks >= 7.2 and 653, signal processing code is expected to clear
the TCB exception count field when returning control back to user code.
This change arranges to do so.  It is believed that this is only an
issue in Kernel mode, and not RTP because there is no exception count
field in RTP mode and no failures have been observed.

gcc/ada/

	* init.c [vxworks] (CLEAR_EXCEPTION_COUNT): New macro.
	(__gnat_clear_exception_count): Remove.
	(__gnat_map_signal): Call CLEAR_EXCEPTION_COUNT().
This commit is contained in:
Doug Rupp 2021-12-20 14:25:30 -08:00 • committed by Pierre-Marie de Rodat
parent 0e9e014cf7
commit 82bd388bf0
1 changed files with 22 additions and 16 deletions
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38
gcc/ada/init.c
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@ -1758,8 +1758,26 @@ extern size_t vxIntStackOverflowSize;
#define INT_OVERFLOW_SIZE vxIntStackOverflowSize
#endif
#ifdef VTHREADS
#include "private/vThreadsP.h"
/* VxWorks 653 vThreads expects the field excCnt to be zeroed when a signal is.
handled. The VxWorks version of longjmp does this; GCC's builtin_longjmp
doesn't. A similar issue is present VxWorks 7.2 and affects ZCX as well
as builtin_longjmp. This field only exists in Kernel mode, not RTP. */
#if defined(VTHREADS) || (!defined(__RTP__) && (_WRS_VXWORKS_MAJOR >= 7))
# ifdef VTHREADS
# include "private/vThreadsP.h"
# define EXCCNT vThreads.excCnt
# else
# include "private/taskLibP.h"
# define EXCCNT excCnt
# endif
# define CLEAR_EXCEPTION_COUNT() \
do \
{ \
WIND_TCB *currentTask = (WIND_TCB *) taskIdSelf(); \
currentTask->EXCCNT = 0; \
} while (0)
#else
# define CLEAR_EXCEPTION_COUNT()
#endif
#ifndef __RTP__
@ -1835,19 +1853,6 @@ __gnat_reset_guard_page (int sig)
return FALSE;
}
/* VxWorks 653 vThreads expects the field excCnt to be zeroed when a signal is.
handled. The VxWorks version of longjmp does this; GCC's builtin_longjmp
doesn't. */
void
__gnat_clear_exception_count (void)
{
#ifdef VTHREADS
WIND_TCB *currentTask = (WIND_TCB *) taskIdSelf();
currentTask->vThreads.excCnt = 0;
#endif
}
/* Handle different SIGnal to exception mappings in different VxWorks
versions. */
void
@ -1959,7 +1964,8 @@ __gnat_map_signal (int sig,
break;
}
}
__gnat_clear_exception_count ();
CLEAR_EXCEPTION_COUNT ();
Raise_From_Signal_Handler (exception, msg);
}