From: Vladimir Murzin <murzin.v@gmail.com>
To: Matvejchikov Ilya <matvejchikov@gmail.com>
Cc: linux-mm@kvack.org
Subject: Re: A question aboout virtual mapping of kernel and module pages
Date: Fri, 20 Dec 2013 03:41:30 +0100 [thread overview]
Message-ID: <20131220024126.GA1852@hp530> (raw)
In-Reply-To: <CAKh5naYHUUUPnSv4skmX=+88AB-L=M4ruQti5cX=1BRxZY2JRg@mail.gmail.com>
Hi Ilya!
On Fri, Dec 20, 2013 at 12:25:13AM +0400, Matvejchikov Ilya wrote:
> I'm using VMAP function to create memory writable mapping as it suggested
> in ksplice project. Here is the implementation of map_writable function:
> ...
>
> This function works well when I used it to map kernel's text addresses. All
> fine and I can rewrite read-only data well via the mapping.
>
> Now, I need to modify kernel module's text. Given the symbol address inside
> the module, I use the same method. The mapping I've got seems to be valid.
> But all my changes visible only in that mapping and not in the module!
>
> I suppose that in case of module mapping I get something like copy-on-write
> but I can't prove it.
>
Looks like I-D cache aliasing... Have you flushed cashes after your
modifications were done?
Vladimir
> Can anyone explain me what's happend and why I can use it for mapping
> kernel and can't for modules?
>
> http://stackoverflow.com/questions/20658357/virtual-mapping-of-kernel-and-module-pages
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next prev parent reply other threads:[~2013-12-20 2:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-19 20:25 Matvejchikov Ilya
2013-12-20 2:41 ` Vladimir Murzin [this message]
2013-12-20 8:25 ` Matvejchikov Ilya
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