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Re: Kernel for Spectre and Meltdown




On Monday, January 29, 2018 09:06:13 AM Michael Fothergill wrote:
> On 29 January 2018 at 13:35, Michael Fothergill <
> 
> michael.fothergill@xxxxxxxxx> wrote:
> >> what has gcc7 to do with the patches is unclear to me, but I admit I
> >> have never worried about.
> > 
> > ​I thought you had to have gcc7 because it included a backport of some
> > code used in GCC 8 that was needed to allow e.g. the spectre fix to work
> > properly.........
> > 
> > If you could use any compiler to do it then earlier my post truly would
> > be BS.​
> 
> PS as I understand (correct me if I am wrong)  the compiler needs to be GCC
> 7.3.0 or greater (I believe the 7.2 rc2 also works); if you used a compiler
> earlier that you would get a kernel that works OK in very respect except
> the for spectre fix itself.

Again, checking / confirming my understanding, if you download a kernel image 
(which is normal for me), there is no need for me to have any version of GCC 
as the image is pre-compiled.

On the other hand, if I download kernel source, I would need GCC, and a 
version that is sufficient for the code.

I have only compiled the kernel a few times, all a long time ago (12 to 15 
years?), on the advice of members of my local LUG, and maybe as a learning 
experience.  It is far from necessary for most of us.  (Some members of the 
LUG seemed to think it was imperative, and maybe it is for older smaller 
machines or maybe to squeeze the very last little bit of efficiency out of the 
system.)