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

From: Bryan O'Donoghue
Date: Fri Sep 26 2014 - 10:30:35 EST


On 26/09/14 15:20, Dave Hansen wrote:
On 09/26/2014 01:44 AM, Bryan O'Donoghue wrote:

+ /*
+ * 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
+ */

That looks fine to me.

OK.

I think to keep everybody aligned/on-the-same-page no pun intended.

We want

+ /*
+ * 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
+ */
+ __flush_tlb();

With the extra __flush_tlb(); on the end.
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