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From: Stefan Roese <ml@stefan-roese.de>
To: Joakim Tjernlund <joakim.tjernlund@transmode.se>
Cc: Scott Wood <scottwood@freescale.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: FTrace on MPC8xx
Date: Wed, 13 Apr 2011 17:21:33 +0200	[thread overview]
Message-ID: <201104131721.34123.ml@stefan-roese.de> (raw)
In-Reply-To: <OF32A80193.EF3E454E-ONC1257871.005204A6-C1257871.00523F24@transmode.se>

Hi Joakim,

On Wednesday 13 April 2011 16:58:21 Joakim Tjernlund wrote:
> > This is on a 2.6.38 kernel (2.6.32 fails too). Debugging shows that
> > __copy_tofrom_user() fails with return code 4 (called via
> > ftrace_modify_code()).
> > 
> > Before digging deeper: Has anybody tried/tested ftrace on MPC8xx? Any
> > ideas what going wrong here?
> 
> Just an idea, remove the usage of dcbX insn, these has been problematic
> before.

I originally tested with 2.6.32. Same problem there. And your 8xx patches with 
the dcbX changes are not included in 2.6.32 yet.

> How big was the size to copy_tofrom_user()? Did it mange to copy
> any bytes?

The size in __copy_tofrom_user is 4. And its the first call in 
ftrace_modify_code() that fails directly. This works just fine on a PPC440EPx 
board.

Best regards,
Stefan

  reply	other threads:[~2011-04-13 15:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-13 14:32 FTrace on MPC8xx Stefan Roese
2011-04-13 14:58 ` Joakim Tjernlund
2011-04-13 15:21   ` Stefan Roese [this message]
2011-04-13 15:38     ` Joakim Tjernlund
2011-04-14 15:59       ` Stefan Roese
2011-04-14 16:49         ` Joakim Tjernlund
2011-04-14 19:21           ` Joakim Tjernlund
2011-04-15  7:22             ` Stefan Roese
2011-04-15  8:46               ` Joakim Tjernlund

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