Re: [PATCH 10/11] perf tools: Add probing for udev86 library

From: Andi Kleen
Date: Wed Mar 30 2016 - 11:08:50 EST

> Yeah, so udis86 also seems to be a pretty old, relatively stale library with no
> support for new instructions AFAICS.

There are lots of new instructions in pull requests on github.

But yes the author seems to be a bit slow in pulling.

> So I'd rather encourage librarizing one of the x86 instruction decoders in
> arch/x86/, and adding pretty-printing functionality to it. The code can already
> see instruction boundaries, which is the hardest part.
> That would also be better supported on non-x86 architectures in the long run:
> triton:~/tip> find arch/ -name insn.c | xargs ls -l
> -rw-rw-r-- 1 mingo mingo 30244 Mar 29 11:24 arch/arm64/kernel/insn.c
> -rw-rw-r-- 1 mingo mingo 1347 Dec 8 06:27 arch/arm/kernel/insn.c
> -rw-rw-r-- 1 mingo mingo 15123 Mar 30 12:31 arch/x86/lib/insn.c
> Such an in-kernel-repo library could also be used by live kernel debuggers such as
> kgdb/kdb, oops/crash-time disassembly printout, etc.
> ... so how about that direction instead?

It's a major project. Who is gonna work on it? Are you volunteering?

Longer term I agree it would be reasonable (if someone can be found to work on it),
but short term udis86 is there and works today.