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From: Oleg Nesterov <oleg@redhat.com>
To: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Cc: bigeasy@linutronix.de, ananth@in.ibm.com,
	srikar@linux.vnet.ibm.com, peterz@infradead.org,
	benh@kernel.crashing.org, mingo@elte.hu, anton@redhat.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/4] uprobes/powerpc: Make use of generic routines to enable single step
Date: Fri, 14 Dec 2012 21:02:41 +0100	[thread overview]
Message-ID: <20121214200241.GA27195@redhat.com> (raw)
In-Reply-To: <20121203150946.7727.82735.stgit@suzukikp>

On 12/03, Suzuki K. Poulose wrote:
>
> Replace the ptrace helpers with the powerpc generic routines to
> enable/disable single step. We save/restore the MSR (and DCBR for BookE)
> across for the operation. We don't have to disable the single step,
> as restoring the MSR/DBCR would restore the previous state.

Obviously I can't review this series (although it looks fine to me).

Just one note,

> @@ -121,7 +132,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
>
>  	WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
>
> -	uprobe_restore_context_sstep(&utask->autask);
> +	uprobe_restore_context_sstep(&utask->autask, regs);

I am not sure ppc needs this, but note that x86 does a bit more.

Not only we need to restore the "single-step" state, we need to
send SIGTRAP if it was not set by us. The same for _skip_sstep.

But even if I am right I do not suggest to change this series,
this can be done as a separate patch.

Oleg.


  parent reply	other threads:[~2012-12-14 20:02 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-03 15:07 [PATCH v2 0/4] uprobes/powerpc: Replace ptrace helpers for single stepping Suzuki K. Poulose
2012-12-03 15:07 ` [PATCH v2 1/4] kprobes/powerpc: Do not disable External interrupts during single step Suzuki K. Poulose
2012-12-11  5:48   ` Suzuki K. Poulose
2013-01-04  4:42     ` Benjamin Herrenschmidt
2013-01-07 12:03       ` Sebastian Andrzej Siewior
2012-12-03 15:08 ` [PATCH v2 2/4] powerpc: Move the single step enable code to a generic path Suzuki K. Poulose
2012-12-10 10:34   ` Ananth N Mavinakayanahalli
2012-12-03 15:09 ` [PATCH v2 3/4] uprobes/powerpc: Introduce routines for save/restore context Suzuki K. Poulose
2012-12-03 15:15   ` Ananth N Mavinakayanahalli
2012-12-03 15:48     ` Suzuki K. Poulose
2012-12-10 10:35   ` Ananth N Mavinakayanahalli
2012-12-03 15:10 ` [PATCH v2 4/4] uprobes/powerpc: Make use of generic routines to enable single step Suzuki K. Poulose
2012-12-10 10:35   ` Ananth N Mavinakayanahalli
2012-12-14 20:02   ` Oleg Nesterov [this message]
2012-12-18  5:11     ` Suzuki K. Poulose
2012-12-18  5:36     ` Ananth N Mavinakayanahalli
2012-12-18 19:10       ` Oleg Nesterov
2012-12-19  4:53         ` Ananth N Mavinakayanahalli

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