Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 21 Mar 2016 23:52:48 +0100 | From | Andi Kleen <> | Subject | Re: Updated version of RD/WR FS/GS BASE patchkit |
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> No. My objection is that there needs to be an explicit statement what > the semantics are. If the agreed-upon semantics are "undefined > behavior if GS != 0 and GSBASE doesn't match the descriptor", so be > it, but this needs to be a conscious decision and needs to be weighed > against the alternatives.
Documentation/x86/fsgs.txt already has this statement:
>>> Another requirement is that the FS or GS selector has to be zero (is normally true unless changed explicitly). When it is non-zero the context switch assumes the bases were loaded through the LDT/GDT, and will reload that. <<<
Is that sufficient?
> > The actual implementation details are just details. They need to > match the intended semantics, of course.
I believe my implementation matches the paragraph above.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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