Re: [PATCH 1/1] x86: fix text_poke

From: David Miller
Date: Fri Apr 25 2008 - 17:02:23 EST


From: "H. Peter Anvin" <hpa@xxxxxxxxx>
Date: Fri, 25 Apr 2008 13:41:00 -0700

> Yes, that should work. It's still ugly, and I have to say I find the
> complexity rather distasteful. I am willing to be convinced it's worth
> it, but I would really like to see hard numbers.

This stuff would have been a lot easier if it just worked with
normal relocations generated by the assembler, and that would
work in such a straightforward way on EVERY architecture.

The immediate instance generators could just use macros that
architectures define, which are given a range of legal values for the
immediate, and the macro emits the inline asm sequence that can
support an immediate value of that range.

Then we do a half-link of the kernel, collect the unresolved
relocations from generated by the immediate macros into a table which
gets linked into the kernel, then resolve them in the final link all
to zero or some defined initial value.

Then it's just a matter of running through the relocation handling
we already have for module loading when changing an immediate
value.

None of this crazy instruction parsing and branch following crap.
I can't believe we're seriously considering this crud. :-/
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