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    SubjectRe: [PATCH] scripts: Make sortextable handle relocations.
    On 04/20/2012 03:41 PM, David Daney wrote:
    > From: David Daney <david.daney@cavium.com>
    >
    > If there are relocations on the __ex_table section, they must be fixed
    > up after the table is sorted.
    >
    > Also use the unaligned safe accessors from tools/{be,le}_byteshift.h
    >
    > Signed-off-by: David Daney <david.daney@cavium.com>
    > ---
    >
    > This should address HPA's concerns about the i386 relocations. The
    > i386 kernel still boots after the sort, but I don't know how to test
    > the relocations, but they sure do look nice! My MIPS64 kernels still
    > boot too, so that is also good.
    >

    Hi...

    This works for absolute relocations of the REL type, but not for
    relocations of the RELA type nor for non-absolute relocations (moving
    those changes the meaning.)

    I think Linus is right and the right thing to do is to switch to using
    relative entries in the exception table; I am currently testing a
    patchset to do exactly that (on x86). It also has the benefit of making
    the table half the size on x86-64. Then we can just zero out the
    .rel[a]__ex_table section and be done with it.

    The trick, of course, is that sorting a relative table is slightly
    different than sorting an absolute table -- the way I'm doing it for the
    in-kernel sorter (still needed for modules) is to add the intra-section
    offset to each entry (both sides) before sorting, then doing a *signed*
    sort, then denormalize again. Alpha does it differently, with custom
    compare and swap routines.

    -hpa


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