[Maverick] [ti-omap4] SRU: A workaround for highmem issue on OMAP4 platform

Tim Gardner tim.gardner at canonical.com
Fri Sep 24 07:50:00 UTC 2010


On 09/24/2010 11:21 AM, Bryan Wu wrote:
> SRU Justification:
>
> Impact:
> There is a critical highmem issue on our latest OMAP4 ES2.0 platform. When we
> build kernel package natively on ES2.0 platform with mem=1G and highmem
> enabled, we will meet 'Bus Error' corruption from gcc shortly. And 'Unhandled
> imprecised external abort' kernel oops messages. Then the whole system will be
> very instable.
>
> Fix: After some debugging, this issue is related to highmem. If we don't use
> mem=1G (no memory in highmem), the corruption is gone. So there is a workaround
> which is CONFIG_VMSPLIT_2G=y. So user and kernel memory split is 2G:2G instead
> of default 3G:1G. We can use all the 1G memory on ES2.0, but don't put any
> memory in highmem. As a result, the issue is gone.
>
> Testcase: Add kernel boot command line mem=1G, build kernel package on ES2.0
> hardware after booting the kernel. The issue is supposed to be gone with 2G:2G
> split config.
>
> A testing kernel is also here:
> http://people.canonical.com/~roc/kernel/lp633227/
>
> Notes: the VMALLOC_END value is wrong in mach-omap2, Nicolas Pitre posted a fixing
> patch to upstream, which is required in this workaround.
>
> BugLink: http://bugs.launchpad.net/bugs/#633227
>
> Plese consider pull from
>   git://kernel.ubuntu.com/roc/ubuntu-maverick lp633227
>
> Bryan Wu (1):
>    UBUNTU: [Config] Enable CONFIG_VMSPLIT_2G=y for OMAP4
>
> Nicolas Pitre (1):
>    ARM: do not define VMALLOC_END relative to PAGE_OFFSET
>
>   arch/arm/mach-aaec2000/include/mach/vmalloc.h   |    2 +-
>   arch/arm/mach-bcmring/include/mach/vmalloc.h    |    2 +-
>   arch/arm/mach-clps711x/include/mach/vmalloc.h   |    2 +-
>   arch/arm/mach-ebsa110/include/mach/vmalloc.h    |    2 +-
>   arch/arm/mach-footbridge/include/mach/vmalloc.h |    2 +-
>   arch/arm/mach-h720x/include/mach/vmalloc.h      |    2 +-
>   arch/arm/mach-integrator/include/mach/vmalloc.h |    2 +-
>   arch/arm/mach-msm/include/mach/vmalloc.h        |    2 +-
>   arch/arm/mach-netx/include/mach/vmalloc.h       |    2 +-
>   arch/arm/mach-omap1/include/mach/vmalloc.h      |    2 +-
>   arch/arm/mach-omap2/include/mach/vmalloc.h      |    2 +-
>   arch/arm/mach-pnx4008/include/mach/vmalloc.h    |    2 +-
>   arch/arm/mach-rpc/include/mach/vmalloc.h        |    2 +-
>   arch/arm/mach-shark/include/mach/vmalloc.h      |    2 +-
>   arch/arm/mach-versatile/include/mach/vmalloc.h  |    2 +-
>   debian.ti-omap4/config/config.common.ubuntu     |    6 +++---
>   16 files changed, 18 insertions(+), 18 deletions(-)
>

So, what do you want me to do? Ricardo is saying this workaround is not 
sufficient.

rtg
-- 
Tim Gardner tim.gardner at canonical.com




More information about the kernel-team mailing list