And an SVC cannot be used very well in certain environments (disabled, locked, SRB mode). In such an environment, an SVC xx would indeed generate a system trace entry, followed immediately by an SVC 13 (ABEND) entry. A BAKR/PR combination would generate at least one system trace entry and would work in these environments.
Bill Fairchild -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Binyamin Dissen Sent: Saturday, December 31, 2011 1:59 PM To: [email protected] Subject: Re: Question on adding an SVC routine dynamically to a running system I would have bigger question - why an SVC at all? SVC's are limited resources. If you will only be working when a server a/s is up, it would make more sense to use a PC. On Sat, 31 Dec 2011 12:53:42 -0600 Dave Day <[email protected]> wrote: :>Peter, :> :>The SVC in question has but one purpose. To generate a system trace :>>>table entry. The code within the SVC clears r15, and then branches r14. :>> Having an SVC that is like that is surely a bad idea if used in a customer :>> shop :>> in production where malicious use of that SVC could compromise system :>> serviceability. :> :> I don't understand your comment. Unless by malicious use you mean that :>the SVC would be executed over and over, just driving up overhead? :> :> I honestly don't see that happening. The code to execute the SVC is :>supplied by me, within a macro. The SVC number will be supplied by my :>server code in my vendor table. The code dropped out by the macro checks :>that my vendor entry is there, and that the SVC number is not 00's. And, I :>would expect anyone assembling the macro into their code would certainly :>control the logic flow with some kind of parm setting/flag byte convention. :>If one of my customers ships their code to their customer with my code :>embedded, and without any check on its execution, it wouldn't do anything :>without my server being there, and up and running. And, if my server is :>there, it would be pretty easy to identify the fact that the code in :>question is executing this SVC without any controls on it. :> :>I can't see any need to set a slip, or find it using IPCS in a dump. :>> That strikes me as a bit short-sighted unless this will never be used in a :>> customer shop. :> :> Why is that short-sighted? Why would I ever set a slip on a BR R14? If :>I need to know where the code is located in a dump, I can get the number :>from my own data area, compute the offset into the SVC table, and then go :>get it from that table. -- Binyamin Dissen <[email protected]> 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 [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
