highbank: smc change in kernel source breaks qemu booting

[dann frazier]

qemu-linaro is no longer able to boot Ubuntu's highbank kernels. I bisected this down to the following changeset in git://kernel.ubuntu.com/ubuntu/ubuntu-precise.git :

commit 4627bd9d888bb1986597525841a1ef304dc2cb70
Author: Rob Herring <email address hidden>
Date: Thu Apr 26 11:40:26 2012 -0500

    UBUNTU: SAUCE: ARM: highbank: Add smc calls to enable/disable the L2

    BugLink: http://bugs.launchpad.net/bugs/1000831

    Linux runs in non-secure mode on highbank, so we need secure monitor calls
    to enable and disable the PL310.

    Signed-off-by: Rob Herring <email address hidden>
    Signed-off-by: Ike Panhc <email address hidden>
    Acked-by: Bryan Wu <email address hidden>
    Signed-off-by: Tim Gardner <email address hidden>

This changeset is in both the current precise and quantal kernels, so neither boot in qemu-linaro at this time. I'm filing this as a qemu-linaro bug instead of a kernel bug as these kernels boot fine on real hardware.

This is reproducible with both qemu-linaro in precise/quantal (w/ the additional highbank fixes in lp:~dannf/qemu-linaro/highbank), as well as latest qemu-linaro from git (top of tree currently at 54ec369).

[Rob Herring (r-herring)]

The attached patch will fix the problem, but this is probably not an acceptable fix for upstream. It assumes that implementing the smc call as a nop would work for all cases. On the the other hand, it does allow the common case of enabling the L2 cache on highbank and omap to work.

[dann frazier (dannf)]

Thanks Rob. I've ported this patch to the qemu-linaro tree and verified that I'm again able to boot Ubuntu kernels with it. I've also applied this to ppa:dannf/qemu-highbank, where I'm collecting all the necessary fixes to boot highbank kernels in precise.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "0001-arm-make-smc-calls-behave-as-nops.patch" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

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[Peter Maydell (pmaydell)]

http://lists.gnu.org/archive/html/qemu-devel/2012-05/msg03012.html is my current proposed long-term upstream-acceptable approach to TrustZone handling.