Bug#800574: Final analysis for Broadwell
On 2015-10-08 22:20, Henrique de Moraes Holschuh wrote:
> tag 800574 + patch
> thanks
>
> Attached updated version of amd64/local-blacklist-on-TSX-Haswell.diff.
> I believe it should be renamed to
> "amd64/local-blacklist-for-Intel-TSX.diff" as it is not just about Intel
> Haswell anymore.
>
> The updated patch has been package-compile-tested on glibc 2.19-22.
>
> This new version of the blacklist patch had the patch header text and
> blacklist code comments updated. It doesn't change anything for
> Haswell. It adds to the blacklist the current Broadwell CPU models and
> steppings.
>
> Broadwell-H with a very recent microcode update (rev 0x12, from
> 2015-06-04) was confirmed to have broken TSX-NI (RTM) and to _leave it
> enabled_ in CPUID, causing glibc with lock elision enabled to SIGSEGV.
> An even more recent Broadwell-H microcode update, rev 0x13 from
> 2015-08-03, is confirmed to (finally) disable the HLE and RTM CPUID
> bits. This should make blacklisting signature 0x40671 uncontroversial.
>
> Refer to https://bugzilla.kernel.org/show_bug.cgi?id=103351 for details.
>
> This version of the blacklist patch leaves upcoming Broadwell-E
> unblacklisted. It also leaves Skylake unblacklisted, as I have not been
> able to confirm whether the newest Skylake-S microcode updates have
> working Intel TSX-NI, or have it disabled.
>
> I propose that the updated blacklist patch be added to glibc in
> unstable, and after it spends a few weeks in testing, that it should
> also be the added to stable through a stable update.
Thanks for the patch, I have committed it to the jessie and the 2.21
branches.
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://www.aurel32.net
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