On 5 January 2016 at 16:19, Ard Biesheuvel [off-list ref] wrote:

There are currently four architectures (x86, ia64, alpha and s390) whose
user-access exception tables are relative to the table entry address rather
than absolute. Each of these architectures has its own search_extable() and
sort_extable() implementation, which are not only mostly identical to each
other, but also deviate very little from the generic absolute implementations
in lib/extable.c that they override.

So before making arm64 the fifth architecture that reimplements this, let's
refactor the existing code so that all of these architectures use common code
for searching and sorting the relative extables. Archs may set
ARCH_HAS_RELATIVE_EXTABLE to indicate that the table consists of a pair of
relative ints, and may define swap_ex_entry_fixup() if the fixup member needs
special treatment in the swapping step of the sorting routine (such as alpha).

[...]

Now that I have collected acks for all the patches, I think this is
good to go in.

@Andrew: since this touches 5 different architectures, is this perhaps
something that could go in via your tree after -rc1?
(assuming that the s390 bugfix has been merged by then)

Thanks,
Ard.