Messages in this thread |  | | | Date | Fri, 8 Feb 2008 12:44:19 +0100 | | From | Andi Kleen <> | | Subject | Re: [PATCH] Use global TLB flushes in MTRR code | |
> because it's not just an open-coded __tlb_flush_all(), it _disables PGE
> and keeps it so while the MTRR's are changed on all CPUs_.
Yes and?
> > Your patch adds __flush_tlb_all() which re-enables the PGE bit in cr4,
> see asm-x86/tlbflush.h:> > /* clear PGE */
> write_cr4(cr4 & ~X86_CR4_PGE);
> /* write old PGE again and flush TLBs */
> write_cr4(cr4);
>
> so we'll keep PGE enabled during the MTRR setting - which changes
> behavior.
It changes behaviour in some minor ways but I don't think it makes any
difference. PGE only influences TLB flushes (according to its
specification) and all the TLB flushes still run with PGE disabled.
-Andi
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