On Fri, Jun 24, 2016 at 12:44 AM, Alan Altmark wrote: > On Thursday, 06/23/2016 at 10:09 GMT, Tom Huegel [email protected]
wrote: I'm telling Hercules it is s z13 (2964 N30) but I don't know that Hercules does anything with that other than reflect it in the STSI instruction... How does UBUNTU determine the hardware level? > Did my post from earlier today not get re-distributed? ________________________________ To be clear, the checks are not based on a machine type or model, per se. Rather, the OS is checking for the availability of needed instructions, service processor functionality, and I/O subsystem capability (collectively called 'facilities'). So you could change the CPU ID to report a zEC12, for example, but unless the various facilities the OS wants are available, you will still get BADCCC. > I.e. a zEC12 GA2 machine will have more facilities available than a GA1 machine, but the machine type and model remains unchanged. > To see how instruction behavior is assessed, look at the STORE FACILITIES LIST EXTENDED (STFLE) instruction. ________________________________ > The host cannot use CPU type-model information to determine functional capability. That way there be flames and damnation for all Eternity. Isn't there a STTGNUIFUNC elf symbol that allows dynamic linker to solve symbols based on CPU functional capabilities ? IIRC there was something like this in between z9 and z10 for glibc optimizations: a "symbol resolver hash function" according to cpu model. With that on mind, zEC12 only instructions - like for transactional memory - COULD allow the same library to run differently in z196 and zEC12/13 at runtime. Still doesn't remove the fact that Ubuntu code was generated with -march=zEC12 and won't probably run on older hardware... > Alan Altmark > Rafael Tinoco ---------------------------------------------------------------------- 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/
