On February 25, 2017 2:38:08 AM PST, Borislav Petkov <b...@alien8.de> wrote: >On Fri, Feb 24, 2017 at 11:41:33AM +0100, Peter Zijlstra wrote: >> So yes, its tricky but it could be done. A new single byte #UD >> instruction would be much nicer though. > >Btw, if we did a new insn which means new functionality instead of >"stealing" an invalid one, we would have to have a fallback for all >those current CPUs which don't support it, which means, alternatives >patching. > >Perhaps it would be better to take one of the invalid ones and future >hw can then extend it and actually make it into a special OS-INT >instruction which is small enough to be inline and can, if hit, run a >handler where you do fixup. > >And then that insn could even have a immed8 arg which you can use to >pass info from the call site. IOW, something like > > ... > OSINT $12 > ... > >and handler inspects opcode and does things based on it... > >Oh well.
You mean like the INT instruction? -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
