Messages in this thread | | | Date | Tue, 18 May 2010 13:34:44 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: Export tsc related information in sysfs |
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On 05/18/2010 01:29 PM, Dan Magenheimer wrote: > > Yes, understood, a minor semantic issue. From a kernel perspective > vsyscalls are kernelspace, so IIUC this is OK with tglx/etc. > > Since vsyscall shouldn't be using rdtsc when the kernel > doesn't trust TSC, it doesn't matter if CR4.TSD is enabled when > the kernel doesn't trust TSC. >
That is correct.
> I'm still not sure if you are in favor of optionally emulating > PL3 rdtsc instructions or not? I thought my proposal was > just filling out some details of your proposal and suggesting > a default.
I'm not in favor of emulating rdtsc instructions. I would consider letting them SIGILL (actually SIGSEGV since RDTSC #GP in userspace) when the TSC is unavailable, though.
It's not clear to me that it's possible, though, since that also affects RDTSCP.
-hpa
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