Messages in this thread | | | Date | Wed, 25 Mar 2015 07:28:46 -0700 | From | Dave Hansen <> | Subject | Re: [PATCH 01/17] x86, fpu: wrap get_xsave_addr() to make it safer |
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On 03/25/2015 05:45 AM, Oleg Nesterov wrote: > So far I do not understand this discussion ;) I didn't see the patches > and other emails...
Hi Oleg,
My patch set apparently didn't make it to LKML, but here are the two relevant ones. We're essentially replacing the MPX use of fpu_save_init(). CPUs with MPX should entirely have eager FPU mode on. But, the edges of the MPX code (do_bounds()) will call this to distinguish a plain #BR exception from a #BR caused by MPX. It may get called on CPUs without eager FPU mode on.
> http://git.kernel.org/cgit/linux/kernel/git/daveh/x86-mpx.git/commit/?h=mpx-v16&id=92d3e7c1664f766142904904e27e126888adb8a7 > http://git.kernel.org/cgit/linux/kernel/git/daveh/x86-mpx.git/commit/?h=mpx-v16&id=18049953ae43a7ffa084a01613c1684bdf24dd2e
All that the MPX code wants here is to read the in-memory copy of the MPX registers, or error out.
So, for the purposes of this series:
With the (so far unmerged to Linus's tree) changes to unlazy_fpu(), does tsk_get_xsave_field()'s use of unlazy_fpu() look correct?
Should we also be renaming tsk_get_xsave_field() to something more appropriate?
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