From: rsmadhvesh@vsnl.net
To: ananth@in.ibm.com
Cc: systemtap@sources.redhat.com, madhvesh.s@ap.sony.com,
lubna@ap.sony.com, satish.v@ap.sony.com
Subject: Re: Kprobes Support for ARM arch
Date: Fri, 12 Jan 2007 05:43:00 -0000 [thread overview]
Message-ID: <e2c8a772bc9c.45a765ff@vsnl.net> (raw)
In-Reply-To: <20070112053157.GA7437@in.ibm.com>
Dear Ananth,
Ananth N Mavinakayanahalli wrote on Friday, January 12, 2007 11:02 am
> On Thu, Jan 11, 2007 at 07:58:07PM +0500, rsmadhvesh@vsnl.net wrote:
>
> Hi Madhvesh,
>
> > Hi All,
> >
> > Recently we completed the kprobes support for ARM architecture
> > targetted at 2.6.16 kernel. I have uploaded these patches in the
> > below CELF wiki page along with few test programs.
> > This implementation is tested using 2.6.16-24 kernel for
> > OMAP5912 OSK reference platform.
>
> I am not familiar with the ARM architecture details... the following
> comments are from a quick glance at the patch.
>
> > The patch is available in the below CELF wiki page
> > http://tree.celinuxforum.org/CelfPubWiki/PatchArchive
> >
> > The patch can be downloaded directly from here
> >
> http://tree.celinuxforum.org/CelfPubWiki/PatchArchive?action=AttachFile&do=get&target=kprobes-arm-patches-2.6.16.24.tgz
> >
> > This implementation supports only kprobes and doesnot
> > support any other variants like jprobes, kretprobes etc.
> > Also it doesnot support branch/jump instructions probing.
>
> How are you ensuring that a kprobe register request on a branch/jump
> instruction fails? I don't see any profiling done to verify what the
> underlying instruction is.
We are working out a way to check for branch/jump instructions
which can be used to take care of runtime crash if probe is placed
for those instructions.
>
> See arch_prepare_kprobe() from the powerpc port as to how we fail
> kproberegistration on certain instructions.
Thank you for the pointers, we are trying to address in same fashion.
>
> > I noticed some discussions regarding ARM kprobes in the
> > archive. We are open to suggestions and how this implementation can
> > be improved.
>
> Given that quite a bit of the kprobes code for any platform is
> architecture specific, its important that your code gets reviewed
> by the
> ARM kernel gurus/maintainers, if you intend that the patch be included
> in the mainline Linux kernels.
>
> Also, you may want to port the patch to the latest kernel. There have
> been some interface changes:
> - kprobe modules are more portable with the addition of in-kernel
> symbol lookup.
> - The page fault case gets its own notifier so there isn't a
> penalty paid
> when kprobes aren't in use.
It will be interesting to merge to main line kernel, i will ask
you if i find any difficulty in porting
Thank you very much for your quick feedback
Best Regards
Madhvesh
next prev parent reply other threads:[~2007-01-12 5:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-11 14:58 rsmadhvesh
2007-01-12 5:32 ` Ananth N Mavinakayanahalli
2007-01-12 5:43 ` rsmadhvesh [this message]
2007-01-18 8:52 ` rsmadhvesh
2007-01-18 9:05 ` rsmadhvesh
2007-01-18 15:43 ` Abhishek Sagar
2007-01-18 17:53 ` Abhishek Sagar
2007-01-12 20:02 ` Quentin Barnes
2007-01-14 12:00 ` rsmadhvesh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e2c8a772bc9c.45a765ff@vsnl.net \
--to=rsmadhvesh@vsnl.net \
--cc=ananth@in.ibm.com \
--cc=lubna@ap.sony.com \
--cc=madhvesh.s@ap.sony.com \
--cc=satish.v@ap.sony.com \
--cc=systemtap@sources.redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).