Messages in this thread | | | Date | Tue, 22 Apr 2014 16:46:59 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE* |
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On Tue, Apr 22, 2014 at 01:23:12PM +0200, Borislav Petkov wrote: > I wonder if it would be workable to use a bit in the espfix PGD to > denote that it has been initialized already... I hear, near NX there's > some room :-)
Ok, I realized this won't work when I hit send... Oh well.
Anyway, another dumb idea: have we considered making this lazy? I.e., preallocate pages to fit the stack of NR_CPUS after smp init is done but not setup the percpu espfix stack. Only do that in espfix_fix_stack the first time we land there and haven't been setup yet on this cpu.
This should cover the 1% out there who still use 16-bit segments and the rest simply doesn't use it and get to save themselves the PT-walk in start_secondary().
Hmmm...
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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