From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, ptx kernel <kernel@pengutronix.de>
Subject: Re: dynamic ftrace/recordmcount.c problem on ARMv5
Date: Wed, 13 Jan 2016 17:23:52 +0100 [thread overview]
Message-ID: <56967A18.1030900@pengutronix.de> (raw)
In-Reply-To: <20160113110856.4e7c5cdb@gandalf.local.home>
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On 01/13/2016 05:08 PM, Steven Rostedt wrote:
> On Wed, 13 Jan 2016 09:51:28 +0100
> Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
>> There are 5 calls to __gnu_mcount_nc in the object file:
>>> $ objdump -x arch/arm/kernel/stacktrace.o | grep R_ARM_CALL | grep __gnu_mcount_nc
>>> 00000054 R_ARM_CALL __gnu_mcount_nc
>>> 0000016c R_ARM_CALL __gnu_mcount_nc
>>> 00000234 R_ARM_CALL __gnu_mcount_nc
>>> 0000026c R_ARM_CALL __gnu_mcount_nc
>>> 000002f4 R_ARM_CALL __gnu_mcount_nc
>>
>> However there are 6 references in the __mcount_loc section:
>>> $ readelf -R __mcount_loc arch/arm/kernel/stacktrace.o
>>>
>>> Hex dump of section '__mcount_loc':
>>> 0x00000000 24000000 54000000 6c010000 34020000 $...T...l...4...
>>> 0x00000010 6c020000 f4020000 l.......
>>
>> Note: The first and wrong offset is 0x24, which is a "bx r6" (see above
>> objdump of stacktrace.o):
>>> 24: e12fff16 bx r6
>
> Interesting. Have you tried a make mrproper and tried again? Also, do
> you use hardlinks with ccache?
That happens on ARMv5 with a clean build. No ccache involved (this issue
should be fixed on >= v4.4)
>> I hacked scripts/Makefile.build to use the perl version of recordmcount,
>> that works without problems.
>
> Note, you could also just removed CONFIG_HAVE_C_RECORDMCOUNT from
> arch/arm/Kconfig.
This is the patch I'm using as a workaround.
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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next prev parent reply other threads:[~2016-01-13 16:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 8:51 dynamic ftrace/recordmcount.c problem on ARMv5 Marc Kleine-Budde
2016-01-13 16:08 ` Steven Rostedt
2016-01-13 16:23 ` Marc Kleine-Budde [this message]
2016-01-13 16:27 ` Steven Rostedt
2016-01-13 16:30 ` Marc Kleine-Budde
2016-02-08 15:38 ` Marc Kleine-Budde
2016-02-08 15:53 ` Steven Rostedt
2016-03-11 9:21 ` Uwe Kleine-König
2016-03-20 3:48 ` Namhyung Kim
2016-03-20 20:00 ` Uwe Kleine-König
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