Message-ID: <4203D793.1040604@nortel.com>
Date: Fri, 04 Feb 2005 14:14:11 -0600
From: Chris Friesen <cfriesen@nortel.com>
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To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
CC: Arjan van de Ven <arjan@infradead.org>, linuxppc-dev@ozlabs.org,
       Linux kernel <linux-kernel@vger.kernel.org>, linuxppc64-dev@ozlabs.org
Subject: Re: question on symbol exports
References: <41FECA18.50609@nortelnetworks.com> <1107243398.4208.47.camel@laptopd505.fenrus.org> <41FFA21C.8060203@nortelnetworks.com> <1107273017.4208.132.camel@laptopd505.fenrus.org> <20050204203050.GA5889@dmt.cnet>
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I've added the ppc64 list to the addressees, in case they are interested.


Marcelo Tosatti wrote:
> On Tue, Feb 01, 2005 at 04:50:16PM +0100, Arjan van de Ven wrote:

>>afaik one doesn't need to do a tlb flush in code that clears the dirty
>>bit, as long as you use the proper vm functions to do so. 
>>(if those need a tlb flush, those are supposed to do that for you
>>afaik).

> Yep, and "proper VM function" is include/asm-generic/pgtable.h::ptep_clear_flush_dirty(),
> which on PPC flushes the TLB.

It turns out that to call ptep_clear_flush_dirty() on ppc64 from a 
module I needed to export the following symbols:

__flush_tlb_pending
ppc64_tlb_batch
hpte_update

>>Also note that your code isn't dealing with 4 level pagetables.... And
>>pagetable walking in drivers is basically almost always a mistake and a
>>sign that something is wrong.

> Or a sign that the core kernel lacks helper functions :) 

Absolutely.  It'd be so nice if there was a simple va_to_ptep() helper 
function available.

Chris
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