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    SubjectRe: [PATCH] ARM: Do not allow unaligned accesses when CONFIG_ALIGNMENT_TRAP
    Will Deacon <> writes:

    > This issue seems to be caused by passing -fconserve-stack to GCC. This
    > was added in 8f7f5c9f ("kbuild: set -fconserve-stack option for gcc
    > 4.5") and as you can see from the archive:
    > it was thought to only have an impact on inlining decisions. Looking at
    > the documentation for GCC 4.6:
    > -fconserve-stack
    > Attempt to minimize stack usage. The compiler will attempt to
    > use less stack space, even if that makes the program slower. This option
    > implies setting the ‘large-stack-frame’ parameter to 100 and the
    > ‘large-stack-frame-growth’ parameter to 400.
    > So it sounds like we might not want to enable this blindly across all
    > architectures. Indeed, on ARM, it encourages the compiler to pack
    > variables on the stack which leads to the weird and wonderful alignment
    > situation that has been encountered in this thread.
    > Can we remove -fconserve-stack from the top-level Makefile (or at least
    > make it conditional by architecture)?

    Sounds like a good idea to me.

    Måns Rullgård
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      Last update: 2011-05-26 20:25    [W:0.020 / U:12.444 seconds]
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