Right. A wild branch could do anything, but I think the damage from key 0 is more likely than that you happen to hit some privileged instruction.
I think you misunderstood my two bullets. The first was the potential damage from supervisor state. The second was potential damage from key 0. Much more potential for damage from the second case. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Binyamin Dissen Sent: Tuesday, June 11, 2019 12:39 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Any way to set the PKM in "open code". On Mon, 10 Jun 2019 13:57:12 -0700 Charles Mills <charl...@mcn.org> wrote: :>> Key0 is much much more dangerous than supervisor state (IMHO) :>Interesting. I never thought of that, but I agree. Which is the more likely :>error? :>- You accidentally code some privileged instruction that you did not intend? Perhaps with a wild branch. Or you branch to user code. :>- You code the wrong register number in an instruction, or destroy or forget :>to initialize the contents of a register (at least on some code paths), or a :>register gets incremented too far? Supervisor state does not you to accidentally overwrite storage in a system key. You need to set the PSW key or use one of the explicit keyed instructions. :>Charles :> :> :>-----Original Message----- :>From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On :>Behalf Of Binyamin Dissen :>Sent: Sunday, June 9, 2019 11:48 PM :>To: IBM-MAIN@LISTSERV.UA.EDU :>Subject: Re: Any way to set the PKM in "open code". :> :>On Sun, 9 Jun 2019 20:15:40 -0400 Rob Schramm <rob.schr...@gmail.com> wrote: :> :>:>I suspect John's answer will be :>:>1) because it's cool to try new things :> :>Well, to do that he could encapsulate this code in a PC-CP with an altered :>AKM. :> :>:>2) because I want to limit the destruction if it goes wrong. :> :>Key0 is much much more dangerous than supervisor state (IMHO) :> :>:>Waiting for the real answer, :>:>Rob :>:> :>:>On Sun, Jun 9, 2019, 6:22 PM Binyamin Dissen <bdis...@dissensoftware.com> :>:>wrote: :>:> :>:>> On Fri, 7 Jun 2019 08:57:38 -0500 John McKown < :>:>> john.archie.mck...@gmail.com> :>:>> wrote: :>:>> :>:>> :>I am not finding this. I want to change the PKM for my running, APF :>:>> :>authorized, program to include key 0. Why? So that I can switch in and :>:>> out :>:>> :>of key 0 using an SPKA instruction rather than MODESET. But mainly so :>:>> that :>:>> :>I can use the MVCSK and MVCDK instructions to read & update key 0, :>fetch :>:>> :>protected, storage without going into key 0. :>:>> :>:>> :>Or am I just being silly (again)? :>:>> :>:>> Why not simply run supervisor state which allows access to all keys? :> :>---------------------------------------------------------------------- :>For IBM-MAIN subscribe / signoff / archive access instructions, :>send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- Binyamin Dissen <bdis...@dissensoftware.com> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
