Re: [Trisquel-users] How will libreboot deal with Meltdown and Spectre?

2018-02-10 Thread lazfamam

Link [1] in above should be,

https://marc.info/?l=linux-kernel&m=151717638018350


Re: [Trisquel-users] How will libreboot deal with Meltdown and Spectre?

2018-02-10 Thread lazfamam
[Upon researching to buy a FSF RYF certified hardware, a few of which were  
using Trisquel, reached here]


[avoiding if & buts at the risk of some of the below going wrong to keep the  
post simple, links are provided for more details]


W.r.t GNU/Linux Kernel on Meltdown & Spectre:
a. Meltdown has been fixed purely in software by 4.15 Kernel [1]
b. Spectre variant 2 fixes also went by 4.15 (note that this in addition  
requires the kernel to be built with compiler supporting "retpoline", GCC 7.3  
has it), all pure software changes
c. Spectre variant 1 fixes is expected to be available by 4.16-rc1 (would  
probably be released by this weekend), again pure software changes


Weekly coverages on related Kernel development, see [2-4]

Now w.r.t (b), there is some confusion (for me), in one of the below lwn  
links it has been mentioned that to fix Spectre v2, there are 2 options,  
either microcode update (for IBRS) or using retpoline (except SkyLake). Linus  
T says [6] that it has been fixed with retpoline, but is seems there is more  
to it than he is aware, in the reply David W (who had been working on these  
patches) says that IBPB support is also required along with retpoline. IBPB &  
IBRS are features added by microcode update. And Greg KH [5] also says he  
needs to update microcode. So there appearance to be a difference in what  
Linus & LWN update says vs David W & Greg KH


So expect for the confusion on (b), other things are entirely handled in  
software.


[1]  
lkml.kernel.org/r/CA+55aFzARtx-nA=d1j7vlolf4fhmjlyriq-pkkoexjutuho...@mail.gmail.com

[2] https://lwn.net/Articles/742702/
[3] https://lwn.net/Articles/742984/bigpage
[4] https://lwn.net/Articles/744039/bigpage
[5] http://kroah.com/log/blog/2018/01/19/meltdown-status-2/
[6] https://lwn.net/Articles/745112/
[7] https://lwn.net/Articles/745113/