Messages in this thread | | | Date | Fri, 22 May 1998 13:03:46 +0200 | From | Martin Mares <> | Subject | Re: Cyrix 6x86MX and Centaur C6 CPUs in 2.1.102 |
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Hi,
> As I understand it, all the bugs listed in /proc/cpuinfo HAVE A > WORKAROUND INSTALLED, so that ANY program trying to activate that bug > MUST fail to do so. As a result, the ONLY meaning that ANY program can > take from a particular processor bug NOT being listed in /proc/cpuinfo > is "Ah, this machine doesn't have a workaround for bug X, so I can use > it to crash this machine" which is the sort of reasoning that VIRUS > programs tend to use and isn't applicable for anything else...
No, several bugs are non-workaroundable -- for example the Pentium FDIV bug. In case an application detects the FDIV bug, it can for example switch to slower fixed-point algorithms which don't suffer from this bug.
> As I see it, there must be a FIXED relationship between CPU clock > speed and TSC frequency, simply due to the fact that anything else > would mean that some sort of random number generator was present. > Remembering the sort of lengths Linux goes to to generate random > numbers, I would find that VERY hard to believe...
I'm not sure about what do specs of different CPU's say on this topic, but I think TSC could possibly be an instruction counter, thus depending on the actual instructions executed.
Have a nice fortnight -- Martin `MJ' Mares <mj@ucw.cz> http://atrey.karlin.mff.cuni.cz/~mj/ Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth "It said, "Insert disk #3," but only two will fit!"
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