Re: 2.4.1-pre1 breaks XFree 4.0.2 and "w"

Andrea Arcangeli
2001-01-12T18:26:43Z

On Fri, Jan 12, 2001 at 09:35:14AM -0800, Linus Torvalds wrote:
>
>
> On Fri, 12 Jan 2001, Andrea Arcangeli wrote:
>
> > On Fri, Jan 12, 2001 at 11:42:32AM -0500, Richard A Nelson wrote:
> > >
> > > Its fine either way on current x86 and many other platforms, but falls
> > > on its face in the presence of asymetric MP.
> >
> > Point taken, feel free to have a can_I_use per-cpu instead of global but don't
> > overwrite the cpu_has with it.
>
> Andrea, the whole POINT of "cpu_has_xxx" is for the kernel to test for
> features like this.

I'm only concerned about the semantics of fxsr and xmm in /proc/cpuinfo, _not_
about the kernel implementation and self contained #defines (that
I'd preferred if they really meant cpu_has and not can_I_use too, but
that's an our internal thing not visible from userspace).

fxsr and xmm in /proc/cpuinfo in 2.4.0, 2.4.1-pre[12], and 2.2.* means
"cpu_has" and _not_ "can_I_use".

So anybody using the fxsr and xmm in the "flags" row of /proc/cpuinfo as the
"can_I_use" will break in any kernel before 2.4.1-pre3.

Anybody reading fxsr and xmm as "cpu_has" will break in any kernel after
2.4.1-pre2.

This all I meant when I said that 2.4.1-pre3 broke /proc/cpuinfo.

I'd prefer if /proc/cpuinfo wasn't broken. That's all.

Andrea