Thanks to Charles M for getting this into a form without the HTML. <snip> First of all -- I am assuming PCRTN resides in the Private Area of the Accessing Address Space (AS1) and PCRTN is defined as a Non- Space Switching, Stacking PC , with a System LX. Is My understanding correct ? </snip>
No it is not. A non-space switch PC (stacking or otherwise) for a system LX will always be in common storage in practice. A similar PC for a non-system LX will be in common storage except for an aberrant case. <snip> Second - if AS2 (The Target Address space) can switch to Supervisor State, issue ATSET and a Cross Memory Post why can't it simply Establish and Setup Its Own Cross Memory Environment, allowing AS1 or any other Address Space the capability of issuing a PC calls to it directly ? The procedure described for AS2 in Figure 38 seems un-necessary to me. </snip> The figure shows how things work. AS2 is the service provider space. Within its initialization, it would have switched to supervisor state, issued ATSET, established an entry table (and system LX/EX's to access it) for "AS1 or any other Address space" to issue the PC's it defined and to access the data it owns. And it might have chosen to use EAX to restrict access to some of its ALET-accessed data. <snip> Third -- Given the technique described for Figure 38 -- wouldn't it be more appropriate for AS1 to define two Non-Space Switching PC routines. One residing in the Private Area of AS1, and the other in LPA. This would allow AS2 to PC to the second PC routine (in LPA) to issue ATSET and a Cross Memory POST. Does this make better sense? </snip> no. AS2 is the (authorized) service provider address space. AS1 is the exploiter/client. The provider sets things up for the exploiter to use. The exploiter is not going to set up anything (and in many cases will not have the authority to do so). I'm not sure what cross-memory post has to do with this. <snip> Fourth -- is any one on this discussion list aware of any IBM product, or OEM Vendor product, or installation written software, that uses the technique described with Figure 38 ? </snip> Every IBM product and ISV exploitation of cross-memory that has access list entries defined with CHKEAX=YES and ACCESS=PRIVATE likely uses this technique. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
