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From: Catalin Marinas <catalin.marinas@arm.com>
To: "Jon Medhurst (Tixy)" <jon.medhurst@linaro.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
	Dave Martin <dave.martin@linaro.org>,
	Laura Abbott <lauraa@codeaurora.org>,
	Nicolas Pitre <nico@fluxnic.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm: Add unwinding annotations for 64bit division functions
Date: Thu, 22 Sep 2011 12:57:13 +0100	[thread overview]
Message-ID: <20110922115713.GJ12025@e102109-lin.cambridge.arm.com> (raw)
In-Reply-To: <1316689606.2053.29.camel@linaro1>

On Thu, Sep 22, 2011 at 12:06:46PM +0100, Jon Medhurst (Tixy) wrote:
> On Thu, 2011-09-22 at 10:48 +0100, Catalin Marinas wrote:
> > We could improve things a bit in the unwinder and assume
> > that if the fault address is the same as the .fnstart address, the
> > return value is always in LR and the SP not affected (that's unwinding
> > bytecode 0xb0). For a few instructions into the function prologue we
> > can't reliably get the unwinding information.
> 
> That would help make it possible to unwind out of kprobes handlers to
> the probed function. The kprobes code itself would need work as well,
> and possibly the undef handler. Do we think it is worthwhile to do
> this? 

Does kprobes need to trace beyond the probed function? If not, you get
the address of the probed function via pt_regs anyway, so no need for
unwinding beyond that.

-- 
Catalin

  reply	other threads:[~2011-09-22 11:57 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-19 22:11 [PATCH] arm: Add unwinding annotations for 64bit division functions Laura Abbott
2011-09-19 23:22 ` Nicolas Pitre
2011-09-20  1:55   ` Laura Abbott
2011-09-20 13:27     ` Nicolas Pitre
2011-09-20 14:57       ` Catalin Marinas
2011-09-21 11:39     ` Dave Martin
2011-09-21 11:55       ` Russell King - ARM Linux
2011-09-21 13:33         ` Dave Martin
2011-09-22  7:28         ` Jon Medhurst (Tixy)
2011-09-22  9:48           ` Catalin Marinas
2011-09-22 11:06             ` Jon Medhurst (Tixy)
2011-09-22 11:57               ` Catalin Marinas [this message]
2011-09-22 12:13                 ` Jon Medhurst (Tixy)
2011-09-22 13:00                   ` Catalin Marinas
2011-09-22 13:19                     ` Jon Medhurst (Tixy)

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