linux-kernel - Re: [PATCH v2 1/2] scripts: Add a recorduidiv program

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Date:	Wed, 25 Nov 2015 23:47:11 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Stephen Boyd <sboyd@...eaurora.org>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	linux-kbuild@...r.kernel.org, Nicolas Pitre <nico@...xnic.net>,
	Arnd Bergmann <arnd@...db.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Måns Rullgård <mans@...sr.com>,
	Michal Marek <mmarek@...e.com>
Subject: Re: [PATCH v2 1/2] scripts: Add a recorduidiv program

On Wed, Nov 25, 2015 at 01:51:03PM -0800, Stephen Boyd wrote:
> The ARM compiler inserts calls to __aeabi_uidiv() and
> __aeabi_idiv() when it needs to perform division on signed and
> unsigned integers. If a processor has support for the udiv and
> sdiv division instructions the calls to these support routines
> can be replaced with those instructions. Therefore, record the
> location of calls to these library functions into two sections
> (one for udiv and one for sdiv) similar to how we trace calls to
> mcount. When the kernel boots up it will check to see if the
> processor supports the instructions and then patch the call sites
> with the instruction.

Do we have any resolution on these programs which modify the object
files in-place, rather than breaking any hard-links which may be
present (eg, as a result of using ccache in hard-link mode) ?

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