Re: signal 8 (floating point exception) upon resume

From: Jung-uk Kim <jkim_at_FreeBSD.org>
Date: Tue, 04 Mar 2014 14:47:29 -0500
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On 2014-03-04 11:24:04 -0500, John Baldwin wrote:
> On Monday, March 03, 2014 6:49:08 pm Adrian Chadd wrote:
>> I'll try this soon.
>> 
>> I had it fail back to newcons, rather than Xorg normally dying 
>> without restoring state. It wouldn't let me spawn a shell. 
>> Logging in worked fine, but normal shell exec would eventually 
>> and quickly lead to failure, dropping me back to the login 
>> prompt.
> 
> If you have set CPUTYPE in /etc/src.conf such that your userland 
> binaries are built with SSE, etc. then I expect most things to 
> break because the FPU is in a funky state without this patch.  I 
> suspect if you don't set CPUTYPE so that your userland binaries do 
> not use the FPU, you can probably resume just fine without this 
> fix.
> 
>> -a
>> 
>> 
>> On 3 March 2014 11:11, John Baldwin <jhb_at_freebsd.org> wrote:
>>> On Friday, February 28, 2014 9:00:57 pm Adrian Chadd wrote:
>>>> On 28 February 2014 15:35, Adrian Chadd <adrian_at_freebsd.org> 
>>>> wrote:
>>>>> ... how'd this ever work in the past then?
>>>>> 
>>>> 
>>>> .. and I've submitted it as a PR:
>>>> 
>>>> kern/187152
>>> 
>>> Complete stab in the dark (not compile tested) here:
>>> 
>>> http://www.FreeBSD.org/~jhb/patches/i386_fpu_suspend.patch

The patch for sys/amd64/amd64/cpu_switch.S is committed:

http://svnweb.freebsd.org/changeset/base/262746

i386 patches may be reviewed by the original author (CC'ed).

Jung-uk Kim
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Received on Tue Mar 04 2014 - 18:47:30 UTC

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