Re: [all better] Re: regression: massive trouble with fpu rework

From: Borislav Petkov
Date: Mon Jun 29 2015 - 04:33:26 EST


On Mon, Jun 29, 2015 at 10:25:29AM +0200, Mike Galbraith wrote:
> On Mon, 2015-06-29 at 08:40 +0200, Ingo Molnar wrote:
> > *
> > Ok, so could you please move the fpu__init_system() further up and see which
> > position is that starts breaking with the BIOS option set?
> >
> > here's the current, broken layout of the code:
> >
> > get_cpu_cap(c);
> > [0] fpu__init_system(c);
> >
> > if (this_cpu->c_early_init)
> > this_cpu->c_early_init(c);

> [0] is the only spot that breaks box.

I bet it is that

/* Unmask CPUID levels if masked: */
if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
MSR_IA32_MISC_ENABLE_LIMIT_CPUID_BIT) > 0) {
c->cpuid_level = cpuid_eax(0);
get_cpu_cap(c);
}
}

in early_init_intel(). If you feel like playing, you might comment it
out to see what happens.

:-)

--
Regards/Gruss,
Boris.

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