Re: [GIT PULL] x86 fixes for 2.6.30-rc8
From: H. Peter Anvin
Date: Sat May 30 2009 - 15:25:00 EST
Michael S. Zick wrote:
> On Sat May 30 2009, Pavel Machek wrote:
>>> --- a/Documentation/kernel-parameters.txt
>>> +++ b/Documentation/kernel-parameters.txt
>>> @@ -1535,6 +1535,10 @@ and is between 256 and 4096 characters. It is defined in the file
>>> register save and restore. The kernel will only save
>>> legacy floating-point registers on task switch.
>>> + noxsave [BUGS=X86] Disables x86 extended register state save
>>> + and restore using xsave. The kernel will fallback to
>>> + enabling legacy floating-point and sse state.
>> Does that mean apps using sse8 will see their registers corrupted if
>> this option is used? Or are new registers sets always added in a way
>> that kernel has to enable them first?
New register sets always require enabling.
> Has this change been tested on the processors that have independent ftp&sse
> units, without the shared registers? Such as the VIA C7-M?
x87 and SSE are always separate. Whether or not register sets are
separate is an architectural issue, and isn't subject to variation
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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