Messages in this thread | | | Subject | Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation | From | David Woodhouse <> | Date | Fri, 26 Jan 2018 18:53:13 +0000 |
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On Fri, 2018-01-26 at 18:44 +0000, Van De Ven, Arjan wrote: > your question was specific to RSB not BTB. But please show the empirical evidence for RSB ?
We were hypothesising, which should have been clear from:
On Fri, 2018-01-26 at 09:11 +0000, David Woodhouse wrote: > Likewise if the RSB only stores the low 31 bits of the target, SMEP > isn't much help there either. > > Do we need to look again at the fact that we've disabled the RSB- > stuffing for SMEP?
... and later...
On Fri, 2018-01-26 at 17:31 +0000, David Woodhouse wrote: > Note, we've switched from talking about BTB to RSB here, so this is a > valid concern if the *RSB* only has the low bits of the target.
I'm glad to hear that it *isn't* a valid concern for the RSB and the code in Linus' tree is correct.
Thank you for clearing that up. [unhandled content-type:application/x-pkcs7-signature] | |