lkml.org 
[lkml]   [2015]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: x86 fpu: command-line parameters broken post-FPU-rewrite
On Wed, Dec 09, 2015 at 09:32:10AM +0100, Ingo Molnar wrote:
>
> * Dave Hansen <dave.hansen@intel.com> wrote:
>
> > Hey Ingo,
> >
> > We were starting to look at reenabling XSAVES support and tried to use the
> > 'noxsave' and 'noxsaves' kernel command-line options. The rewrite moved the FPU
> > initialization to before we even are parsing command-line options, even the
> > early_param()s.
> >
> > Do you have any preferences on how it gets fixed?
> >
> > The most obvious thing would be to just defer as much of the FPU setup as we can
> > until after parse_early_param() has happened. The only other think I can think
> > of doing would be to try to do some *really* early, simple, command-line parsing
> > to look for 'noxsave' and friends.
> >
> > Thoughts?
>
> Hm, so given that having the FPU operational is key to a functioning kernel (and
> other kernel subsystems may make use of FPU functionality), I'd rather bring
> option parsing earlier than change the FPU setup sequence. FPU setup should be
> done when we identify the CPU - not 'very late' as we used to.

We already have early cmdline parsing: arch/x86/lib/cmdline.c

See users for examples.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.


\
 
 \ /
  Last update: 2015-12-09 20:41    [W:0.044 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site