Thanks, Mike,Unfortunately, the situation is more complex. This is a
transaction processing system, with multiple TCBs. Control gets passed to
application programs from these master TCBs. We don't want the application
programs to access page zero, but the calling "tcb loops" can do so and does
too.There are a large number of erroneously coded MVC, CLC etc pointing to the
low core at present in application programs. All was working fine till zOS 2.5
just by chance, but after 2.5 things changed. Low-core values changed and
programs started to hit with bugs. FLAG(PAGE0) helped to identify assemble time
cases. Worried about run time cases now. Just thinking, could I be able to add
some common macro at the beginning of these application programs which could
potentially make them dump rather than proceed with the wrong data.Regards,Syama
On Tuesday, March 28, 2023 at 11:53:44 AM GMT+13, Mike Shaw
<[email protected]> wrote:
Syama,
This may help. It is a ZAD SLIP trap.
https://www.ibm.com/docs/en/zos/2.3.0?topic=traps-slip-zero-address-detection-zad
Mike Shaw
MVS/QuickRef Support
Chicago-Soft, Ltd.
On Mon, Mar 27, 2023, 6:47 PM syama prasad <
[email protected]> wrote:
> Hi,
> Is it possible to force an Assembler program to hit an access error if it
> tries to load data from the low core (page starting from address
> zero)?Assembler *PROCESS FLAG(PAGE0) " helps to find cases like MVC
> TARGET,1But will it be possible to have a run time detection and possibly a
> dump if the program tries to do things likeLA R5,1MVC
> TARGET,0(R5)Basically, any way to restrict access of an application program
> to PSA- first control block?
> Regards,Syama
>
