From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linuxppc-dev@lists.ozlabs.org,
lkml <linux-kernel@vger.kernel.org>,
Paul Mackerras <paulus@samba.org>,
Anton Blanchard <anton@samba.org>,
michael@ellerman.id.au, Ingo Molnar <mingo@elte.hu>,
peterz@infradead.org,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: [PATCH v3 2/2] powerpc: Uprobes port to powerpc
Date: Wed, 22 Aug 2012 14:02:25 +0530 [thread overview]
Message-ID: <20120822083224.GC29216@in.ibm.com> (raw)
In-Reply-To: <20120821130930.GA10382@redhat.com>
On Tue, Aug 21, 2012 at 03:09:30PM +0200, Oleg Nesterov wrote:
...
> > This is true for Intel like architectures that have *one* swbp
> > instruction. On Powerpc, gdb for instance, can insert a trap variant at
> > the address. Therefore, is_swbp_insn() by definition should return true
> > for all trap variants.
>
> Not in this case, I think.
>
> OK, I was going to do this later, but this discussion makes me think
> I should try to send the patch sooner.
>
> set_swbp()->is_swbp_at_addr() is simply unneeded and in fact should
> be considered as unnecessary pessimization.
>
> set_orig_insn()->is_swbp_at_addr() makes more sense, but it can't fix
> all races with userpace. Still it should die.
>
> > OK. I will separate out the is_swbp_insn() change into a separate patch.
>
> Great thanks. And if we remove is_swbp_insn() from set_swbp() and
> set_orig_insn() then the semantics of is_swbp_insn() will much more
> clear, and in this case I powerpc probably really needs to change it.
Oleg,
I have posted a new version for review [1] without the is_swbp_insn()
change. I will await your changes around is_swbp_at_addr() and make
changes to the powerpc code if necessary.
Regards,
Ananth
[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100524.html
prev parent reply other threads:[~2012-08-22 8:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-26 5:19 [PATCH 1/2] powerpc: Add trap_nr to thread_struct Ananth N Mavinakayanahalli
2012-07-26 5:20 ` [PATCH v3 2/2] powerpc: Uprobes port to powerpc Ananth N Mavinakayanahalli
2012-07-27 8:40 ` Srikar Dronamraju
2012-08-15 16:59 ` Oleg Nesterov
2012-08-15 21:41 ` Benjamin Herrenschmidt
2012-08-16 5:00 ` Ananth N Mavinakayanahalli
2012-08-16 15:21 ` Oleg Nesterov
2012-08-17 5:13 ` Ananth N Mavinakayanahalli
2012-08-17 15:00 ` Oleg Nesterov
2012-08-21 11:24 ` Ananth N Mavinakayanahalli
2012-08-21 13:09 ` Oleg Nesterov
2012-08-22 8:32 ` Ananth N Mavinakayanahalli [this message]
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