From mboxrd@z Thu Jan 1 00:00:00 1970 From: "George Pontis" References: <009c01cd539e$e9f81420$bde83c60$@com> <4FE9BDA9.3000209@xenomai.org> In-Reply-To: <4FE9BDA9.3000209@xenomai.org> Date: Wed, 27 Jun 2012 08:34:16 -0700 Message-ID: <013901cd547a$50179b00$f046d100$@com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Language: en-us Subject: Re: [Xenomai] ARM, exception #0 ? List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai@xenomai.org =20 > On 06/26/2012 03:23 PM, George Pontis wrote: > > Running Xenomai 2.6.0 on an ARM at91sam9g45. I recently updated from > Adeos > > patch adeos-ipipe-3.0.13-arm-1.18-05 to adeos-ipipe-3.0.13-arm-1.18- > 09. Then > > built a new kernel and gave it to the application developers for a > test. > > There were other changes in the root FS and a few tweaks in the > kernel, but > > none that looked (to me) like they would affect Xenomai. They report > this > > new error: > > > >> Xenomai: Switching ADC Task to secondary mode after exception #0 > from > >> user-space at 0xffff0fbc (pid 723) > > > > And then nothing about the app works any more. What does this mean ? >=20 > It means there is a fault, when the PC is around 0xffff0fbc, that is = in > the tsc emulation kernel helper. Could you try reverting this commit ? >=20 I tried reverting to adeos-ipipe-3.0.13-arm-1.18-05 without any other = changes, and this error still occurs. The address of the exception is = exactly the same. So I did some experiments to try to narrow this down. = First thing, it does not happen with any Xenomai user app. I wrote a = different app some time ago that runs without error on all the = Xenomai-enabled kernels. I also went back to a previous kernel where this app runs without = causing the error. That kernel was the same 3.0.13 with = adeos-ipipe-3.0.13-arm-1.18-05.patch and the same Xenomai 2.6.0. The = root FS was identical. Everything was built with the same GCC 4.5.3. = What was different about it were some other features that were enabled = or disabled in the kernel. Possibly it is one or more of these changes = that is aggravating the problem with this one app: 1) Turned off JFFS2, IDE 2) Turned on ext4 support 3) Enabled Atmel FB and SPI-based touchscreen controller 4) Disabled shmem 5) Disabled UID16 and "sysctl syscall" Do any of these seem like they could be a factor ? I should emphasize = that we are still pretty new to Xenomai. It is more likely that we have = made a mistake in the app than that there is a Xenomai bug that nobody = else has caught yet. Any suggestions where to go next to get to the = bottom of this ? George=20