Re: [PATCHES] gnu: linux-libre: Full retpoline support on x86 [spectre mitigation]

[Mark H Weaver <mhw@netris.org>]

ludo@gnu.org (Ludovic Courtès) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> Here are two patches that:
>>
>> * Add gcc-7.3.0-RC-20180117, which includes support for retpoline.
>> * Use gcc-7.3 to build linux-libre on x86 systems.
>
> With GCC 7.3.0 now out, I think you can go ahead.
>
>> From 387a02c3f9e157bdf40b2b5ad0e53e5b209f3aa5 Mon Sep 17 00:00:00 2001
>> From: Mark H Weaver <mhw@netris.org>
>> Date: Sat, 20 Jan 2018 15:15:19 -0500
>> Subject: [PATCH 1/2] gnu: gcc: Add gcc 7.3.0-RC-20180117 [includes retpoline
>>  support].
>>
>> * gnu/packages/gcc.scm (gcc-7.3): New variable.
>
> I think we can upgrade ‘gcc-7’ directly instead of introducing a new
> ‘gcc-7.3’ variable.  Thoughts?

Agreed.

>> --- a/gnu/packages/linux.scm
>> +++ b/gnu/packages/linux.scm
>> @@ -283,6 +283,12 @@ for ARCH and optionally VARIANT, or #f if there is no such configuration."
>>         ("bc" ,bc)
>>         ("openssl" ,openssl)
>>         ("kmod" ,kmod)
>> +       ,@(match (system->linux-architecture
>> +                 (or (%current-target-system) (%current-system)))
>> +           ((or "x86_64" "i386")
>> +            `(("gcc" ,gcc-7.3)))
>
> Perhaps add a comment that this is for the retpoline mitigation.

Agreed.  I pushed these changes on Thursday.  Fortunately, I had already
done the things you suggested here.

      Thanks!
        Mark