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    SubjectRe: Bug#609371: linux-image-2.6.37-trunk-sparc64: module scsi_mod: Unknown relocation: 36
    * Sam Ravnborg (sam@ravnborg.org) wrote:
    > >
    > > If my memory serves me correctly, I think "long long" is aligned on 4 bytes on
    > > ppc32, but on 8 bytes on x86_32 (yeah, that's weird). How about we create a
    > > #define __long_long_aligned __attribute__((__aligned__(__alignof__(long long))))
    >
    > #define __u64_aligned __attribute__((__aligned__(__alignof__(long long))))
    >
    > A bit shorter but maybe less obvious.

    Yep, that would make sense.

    I'm tempted to try creating

    #defined __u64_packed_aligned __attribute__((__packed__, __aligned__(__alignof__(long long))))

    in the hope that gcc sees this as a strict alignment requirement (including a
    max bound) rather than just a hint. From what I gather in my reading of

    http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html

    "The aligned attribute can only increase the alignment; but you can decrease it
    by specifying packed as well. See below."

    gcc seems to support having both specified. I think this would provide the kind
    of alignment guarantees we really need here: both specifying the minimum _and_
    maximum alignment.

    Thoughts ?

    Mathieu

    >
    > Sam

    --
    Mathieu Desnoyers
    Operating System Efficiency R&D Consultant
    EfficiOS Inc.
    http://www.efficios.com


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