Re: [GIT PULL] x86 fixes

H. Peter Anvin
2015-08-18T00:01:45Z

I ran a hacked Qemu with FPU off.

On August 17, 2015 4:59:18 PM PDT, Andy Lutomirski <luto@amacapital.net> wrote:
>On Mon, Aug 17, 2015 at 1:01 AM, Ingo Molnar <mingo@kernel.org> wrote:
>> So when I re-introduced static allocations math-emu started working
>again, to a
>> limited degree: on a modern distro, trying to boot /bin/bash I got a
>prompt, but
>> various programs would segfault. I did not investigate it any deeper,
>I suppose
>> the FPU emulation does not go far enough for modern user-space, or
>maybe it has
>> more bugs.
>>
>
>Were you testing with just no387 or did you run a VM with SSE2 and
>such turned off?
>
>There's a *lot* of userspace that incorrectly checks for instructions
>without checking for the state support. I've filed bugs against
>libgcc for this and they're still not fixed IIRC.
>
>--Andy

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