| Date | Wed, 1 Jul 2015 12:24:10 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v4 08/17] x86/entry: Add enter_from_user_mode and use it in syscalls |
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On Mon, Jun 29, 2015 at 12:33:40PM -0700, Andy Lutomirski wrote: > Changing the x86 context tracking hooks is dangerous because there > are no good checks that we track our context correctly. Add a > helper to check that we're actually in CONTEXT_USER when we enter > from user mode and wire it up for syscall entries. > > Subsequent patches will wire this up for all non-NMI entries as > well. NMIs are their own special beast and cannot currently switch > overall context tracking state. Instead, they have their own > special RCU hooks. > > This is a tiny speedup if !CONFIG_CONTEXT_TRACKING (removes a > branch) and a tiny slowdown if CONFIG_CONTEXT_TRACING (adds a layer
CONTEXT_TRACING?!
Oh noooo, not another tracer :-P
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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