[linuxsh-dev] Re: bad alignment fixup

[Jesper S. <js...@re...>]

>>>>> "David" == David Woodhouse <dw...@in...> writes:
David> You mean to search the exception table before attempting the
David> fixup, and to refuse to do the fixup if there's an entry for
David> $pc? I don't like that very much. I think we _should_ be fixing
David> up unaligned userspace accesses. Not only when they're accessed
David> from the kernel, but when they happen entirely in userspace.

I don't agree. Nasty DOS you could get out of that - simply make an
infinite loop read from odd addresses and the kernel will be wasting
tons of time fixing up those accesses. User space apps should die if
they do unaligned access.

David> At the moment, I'm more concerned about what happens when the
David> offending insn is in a branch delay slot. It looks like
David> regs->pc will be pointing to the branch insn iff it was taken,
David> so in that case, we have to fix up the insn at $pc+2 and then
David> also emulate the branch insn follow the branch.

Urgh. Messy.

Jesper