From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Date: Fri, 11 Sep 2009 18:35:59 +0000 Subject: Re: User mode address error problems on 7763 Message-Id: <20090911183557.GA21695@console-pimps.org> List-Id: References: <6e6aa1a80909111106l6dbcfccag4e9e7a3abb922688@mail.gmail.com> In-Reply-To: <6e6aa1a80909111106l6dbcfccag4e9e7a3abb922688@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sh@vger.kernel.org On Fri, Sep 11, 2009 at 01:06:31PM -0500, Dale Larson wrote: > I've been porting linux (2.6.30.2) to our 7763 based platform and the > kernel seems to be running fine but when user mode programs run I > randomly get errors like this: > > [ 8.419557] VFS: Mounted root (nfs filesystem) on device 0:9. > [ 8.431863] Freeing unused kernel memory: 80k freed > init started: BusyBox v1.14.3 (2009-09-04 15:19:48 CDT) > [ 8.682286] Fixing up unaligned userspace access in "mount" pid2 > pc=0x295583d0 ins=0x60b2 > [ 8.699336] Sending SIGBUS to "mount" due to unaligned access (PC > a0042955 PR 295583da) > Populating /dev using udev: done > > Another example: > > Starting dropbear sshd: OK > [ 484.428550] Fixing up unaligned userspace access in "touch" pid8 > pc=0x295583d0 ins=0x60b2 > [ 492.438796] Sending SIGBUS to "touch" due to unaligned access (PC > a0042955 PR 295583da) > > The SIGBUS kills the process. I've tried various versions of linux > form kernel.org: 2.6.28, 2.6.29, 2.6.30 and all have the same > behaviour. > > Using JTAG I see that I'm having both data alignment and PC alignment > problems. If I turn off the I&D caching this problem doesn't happen. > This is most likely to be the cache aliasing bug I'm hunting. What are the dimensions of your cache? Can you tried building a kernel from the sh/cachetlb branch at, git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6.git and see if the issue persists? Paul has made some changes recently that might work around this problem.