[v3] retpoline: add clang support + Kconfig selectable

[PATCH v3 0/3] retpoline: add clang support + Kconfig selectable

Posted by Roger Pau Monne 2 years, 2 months ago

Hello,

The following series adds retpoline support for clang builds, and also
allows the user to select whether to enable retpoline support at build
time via a new Kconfig option.

I've tried adding a suitable description to the Kconfig option, but I'm
sure there's room for improvement.

Thanks, Roger.

Roger Pau Monne (3):
  x86/retpoline: split retpoline compiler support into separate option
  x86/clang: add retpoline support
  x86/Kconfig: introduce option to select retpoline usage

 xen/arch/x86/Kconfig |  5 +++--
 xen/arch/x86/arch.mk | 13 +++++++++----
 xen/common/Kconfig   | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 6 deletions(-)

-- 
2.34.1

Re: [PATCH v3 0/3] retpoline: add clang support + Kconfig selectable

Posted by Andrew Cooper 2 years, 2 months ago

On 18/02/2022 14:34, Roger Pau Monne wrote:
> Hello,
>
> The following series adds retpoline support for clang builds, and also
> allows the user to select whether to enable retpoline support at build
> time via a new Kconfig option.
>
> I've tried adding a suitable description to the Kconfig option, but I'm
> sure there's room for improvement.
>
> Thanks, Roger.
>
> Roger Pau Monne (3):
>   x86/retpoline: split retpoline compiler support into separate option
>   x86/clang: add retpoline support
>   x86/Kconfig: introduce option to select retpoline usage

Thanks.  I think that's looking much better IMO.

One thing, we want CC_HAS_* for consistency.  I can fix this on commit.

Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

Re: [PATCH v3 0/3] retpoline: add clang support + Kconfig selectable

Posted by Roger Pau Monné 2 years, 1 month ago

On Fri, Feb 18, 2022 at 03:45:12PM +0000, Andrew Cooper wrote:
> On 18/02/2022 14:34, Roger Pau Monne wrote:
> > Hello,
> >
> > The following series adds retpoline support for clang builds, and also
> > allows the user to select whether to enable retpoline support at build
> > time via a new Kconfig option.
> >
> > I've tried adding a suitable description to the Kconfig option, but I'm
> > sure there's room for improvement.
> >
> > Thanks, Roger.
> >
> > Roger Pau Monne (3):
> >   x86/retpoline: split retpoline compiler support into separate option
> >   x86/clang: add retpoline support
> >   x86/Kconfig: introduce option to select retpoline usage
> 
> Thanks.  I think that's looking much better IMO.
> 
> One thing, we want CC_HAS_* for consistency.  I can fix this on commit.
> 
> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

Could the patches be backported to stable-4.16?

Thanks, Roger.

Re: [PATCH v3 0/3] retpoline: add clang support + Kconfig selectable

Posted by Jan Beulich 2 years, 1 month ago

On 30.03.2022 12:21, Roger Pau Monné wrote:
> On Fri, Feb 18, 2022 at 03:45:12PM +0000, Andrew Cooper wrote:
>> On 18/02/2022 14:34, Roger Pau Monne wrote:
>>> Hello,
>>>
>>> The following series adds retpoline support for clang builds, and also
>>> allows the user to select whether to enable retpoline support at build
>>> time via a new Kconfig option.
>>>
>>> I've tried adding a suitable description to the Kconfig option, but I'm
>>> sure there's room for improvement.
>>>
>>> Thanks, Roger.
>>>
>>> Roger Pau Monne (3):
>>>   x86/retpoline: split retpoline compiler support into separate option
>>>   x86/clang: add retpoline support
>>>   x86/Kconfig: introduce option to select retpoline usage
>>
>> Thanks.  I think that's looking much better IMO.
>>
>> One thing, we want CC_HAS_* for consistency.  I can fix this on commit.
>>
>> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
> 
> Could the patches be backported to stable-4.16?

Hmm, generally I'd view them as a feature rather than a bug fix, but
since you're explicitly requesting their backporting I guess I should
rather look at them from an improved-security angle.

Jan