Thanks Neale! In my case I’m using diag a0. Though I may want to do this for other diag instructions too.
Getting in/out of supervisor state is my next hurdle. :-) I was going to use stidp to make sure I was actually on VM but that got “Illegal Instruction” when it ran. Maybe there’s a function I can call, or I can read /proc/cpuinfo to verify A-it’s IBM/S390 and B-VM is running. I don’t like the idea of reading a whole “file” to provide what a single instruction can give me. I still have to figure out how to get in and out of supervisor state for the diag though. Thanks for tip on generating the machine code. That’s great! :-) Cheers, Don On Sat, Nov 10, 2018 at 03:31 Neale Ferguson <[email protected]> wrote: > .byte 0x83, 0x12, 0x00, 0x08 > > == diag 1,2,8 (CP command) > > You can either load r1/r2 in the _asm_ section or tell gcc to bind the > variables to the registers. > > Remember, though, that diag is a privileged instruction and won't work in > a userland program. > > In what particular diag are you interested? > > > -------- Original message -------- > From: Donald Russell <[email protected]> > Date: 11/10/18 06:00 (GMT-05:00) > To: [email protected] > Subject: [LINUX-390] Using diagnose instruction from C on RHEL 7 > > Hello, > > I want to write a program in C and use a diagnose instruction. > > I thought I could do > > __asm___( “ diag ... “ ...); > > but that fails because diag is not a real instruction mnemonic. When I use > gcc to compile and link I get an error: > > Program.c(.text+0x578): undefined reference to ‘x480a032’ > collect2: error: ld returned 1 exit status > > I thought I could code dc x’8312....’ and force the use of registers 1 and > 2 but it complains that dc is not valid. (The doc says instructions > including directives are ok. But obviously not dc directives. :-) I also > tried upper case just to be thorough) > > How can I coerce C into generating a diagnose instruction? > > Thanks, > Don > > ---------------------------------------------------------------------- > 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/ > ---------------------------------------------------------------------- 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/
