Messages in this thread | | | Date | Mon, 11 Aug 2008 12:24:59 -0700 | From | "H. Peter Anvin" <> | Subject | Re: Kernel oops with 2.6.26, padlock and ipsec: probably problem with fpu state changes |
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Ingo Molnar wrote: > * Suresh Siddha <suresh.b.siddha@intel.com> wrote: > >> Reported-and-bisected-by: Wolfgang Walter <wolfgang.walter@stwm.de> >> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> > > no fundamental objection to the x86 bits. > > shouldnt this: > > + if (!in_interrupt()) > + return 0; > > just be eliminated and the cr0/TS save/restore be made unconditional? > irq-assymetric APIs are not nice in general. > > Reading/setting cr0 isnt _that_ slow. (or if it is, by how much does it > slow things down, exactly?) >
Setting it is relatively slow. I think that's part of the reason for special instructions to muck with the TS flag.
Reading it might be slow on obsolete processors.
-hpa
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