Re: [PATCH] x86, setup: add __flush_tlb() for Intel Quark X1000

From: Bryan O'Donoghue
Date: Fri Sep 26 2014 - 04:44:24 EST

On 26/09/14 06:32, Dave Hansen wrote:
I'd just say:

Quark X1000 wrongly advertises PGE. Work around this with an
unconditional full flush using a CR3 write instead of CR4.PGE:

Hi Dave.

In another thread with Ingo Molnar and Henrique de Moraes Holschuh the following text was proposed.

+ /*
+ * Locate the page directory and flush the TLB.
+ *
+ * On Quark X1000 CPUs we still have the PGE bit incorrectly set
+ * due to a processor erratum, so __flush_tlb_all() is not yet
+ * doing what it says. Fortunately we have a cr3 flush here,
+ * which is what is needed in this processor to flush TLBs, so
+ * there's no need to add a Quark X1000 quirk here.
+ *
+ * early_init_intel will unset the X86_FEATURE_PGE flag later
+ * and __flush_tlb_all() will flush via cr3
+ */

Path submitted as "[PATCH] x86: Quark: Comment setup_arch for TLB/PGE bugfix"

Does that work for you ?

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