Date: Tue, 01 Jun 2010 09:35:06 -0700 From: Marcel Moolenaar <xcllnt@mac.com> To: Alan Cox <alc@cs.rice.edu> Cc: Marcel Moolenaar <marcel@freebsd.org>, ppc@freebsd.org Subject: Re: BookE pmap_enter() bug? Message-ID: <B5C7F1F3-AD95-49C9-AC9F-02AFCB3FEF06@mac.com> In-Reply-To: <4C053389.1040204@cs.rice.edu>
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On Jun 1, 2010, at 9:21 AM, Alan Cox wrote:
> I've been reviewing the various pmap_enter() implementations and came across the following bit of code in the BookE pmap_enter():
>
> if (prot & VM_PROT_EXECUTE) {
> flags |= PTE_SX;
> if (!su)
> flags |= PTE_UX;
>
> /*
> * Check existing flags for execute permissions: if we
> * are turning execute permissions on, icache should
> * be flushed.
> */
> if ((flags & (PTE_UX | PTE_SX)) == 0)
> sync++;
> }
>
>
> This will never flush the instruction cache because the new flags, not the old flags, are being used. I suspect that the attached change should be made.
*snip*
You're right.
I'm not aware of icache incoherency problems on BookE, so this raises
the question as to whether we actually need to worry about syncing the
icache here. But that's ortogonal...
--
Marcel Moolenaar
xcllnt@mac.com
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