I think it's an excellent method of providing a finer grained mechanism of privileges rather than just yes or no (recall the initial UNIX model had rings of privileges or was that just Dante and the Seven levels of hell?). In any event it makes sense in z where you don't want a TSO task being able to do memory mapped i/o but would like a Linux process to be allowed to do so.
What do we want? Semi privileges! When do we want it? Sometimes! -------- Original message -------- From: Alan Altmark <[email protected]> Date: 2015/06/03 20:07 (GMT-05:00) To: [email protected] Subject: Re: [LINUX-390] MMIO On Wednesday, 06/03/2015 at 05:54 EDT, Neale Ferguson <[email protected]> wrote: > Check your 370 reference card IPK, IVSK, EPAR and ESAR are defined as > semi-privileged. I think 390 also had them. Yes, it did. I stand corrected! The next time the Defenders get out their pointy little sticks, I'm going to drag out this particular chainsaw. Alan Altmark Senior Managing z/VM and Linux Consultant Lab Services System z Delivery Practice IBM Systems & Technology Group ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 [email protected] IBM Endicott ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
