It doesn't matter if CR0 bit 38 is on or off in this case. If this bit is
on, It only allows read access to address 0-2047. The PSA part 2048-4095 is
ALWAYS protected. This is expected.
The problem I'm facing is that I can view the protected PSA part 2048-4095
when I'm in a z/OS 3.1 on a z14.
When I run a simple program (User key 8) like this:
psatest csect
psatest amode 31
psatest rmode any
bakr r14,r0
lr r12,r15
using psatest,r12
l r15,2048
xr r15,r15
pr
end psatest
- On z/OS 3.1 running on a z15 this program ABEND S0C4-4 -> This is the
expected result.
- On z/OS 3.1 running on a z14 this program executes normally. -> This is
NOT the expected result !!
On Fri, Aug 1, 2025 at 1:23 PM salva <[email protected]> wrote:
> At the very least, take the dumps and compare bit 38 of CR0.
>
> El vie, 1 ago 2025 a las 18:09, Philippe Leite (<
> [email protected]>) escribió:
>
> > As I said to Rob, I already knew this POP rule for a long time, but it
> > doesn't answer this situation I'm facing.
> > It's exactly the same z/OS 3.1 version (same source and PTF level) but
> it's
> > working differently on a z14 and z15.
> >
> > Philippe Leite
> > z/OS System Programmer
> >
> > On Fri, Aug 1, 2025 at 1:04 PM salva <[email protected]> wrote:
> >
> > > From the POP:
> > >
> > > "Fetch-Protection-Override Control
> > > Bit 38 of control register 0 is the fetch-protection-
> > > override control. When the bit is one, key-controlled
> > > fetch protection is ignored for locations at effective
> > > addresses 0-2047."
> > >
> > > I don't know why it's different in your cases.
> > >
> > > El vie, 1 ago 2025 a las 16:40, Philippe Leite (<
> > > [email protected]>) escribió:
> > >
> > > > Interestingly, I am experiencing the same situation here.
> > > > In an LPAR running z/OS 3.1 on a z14, when I send the command “TSO
> > ISRDDN
> > > > B 800.”, I can view the contents of PSA 2048-4095.
> > > > But when I am in another LPAR with the same z/OS 3.1 on a z15, the
> same
> > > > command “TSO ISRDDN B 800.” shows me an error message “Storage
> > > unavailable.”
> > > >
> > > >
> > > > Philippe Leite
> > > > z/OS System Programmer
> > > >
> > > >
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> >
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> >
>
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