[RFC PATCH] ARM: Add generic instruction opcode manipulation helpers

[Dave Martin]

On Tue, Dec 06, 2011 at 03:08:55PM +0000, Will Deacon wrote:
> Hi Dave,
> 
> On Fri, Nov 25, 2011 at 11:28:13AM +0000, Dave Martin wrote:
> > This patch adds some endianness-agnostic helpers to convert machine
> > instructions between canonical integer form and in-memory
> > representation, and also provides a transparent way to read a
> > single Thumb instruction from memory, without the need to know the
> > size in advance or write explicit condition checks.
> > 
> > A canonical integer form for representing instructions is also
> > formalised here.
> > 
> > Signed-off-by: Dave Martin <dave.martin at linaro.org>
> > ---
> >  arch/arm/include/asm/opcodes.h |  162 ++++++++++++++++++++++++++++++++++++++++
> >  1 files changed, 162 insertions(+), 0 deletions(-)
> >  create mode 100644 arch/arm/include/asm/opcodes.h
> 
> It looks like I might need to implement a basic disassembler for the
> hw_breakpoint code and I would certainly like to reuse as much code as I
> can. This header could obviously provide the code to fetch and format the
> instruction, but it would be nice to have some extra helpers to aid
> decoding.
> 
> Tixy - how much work do you reckon it would be to rework your kprobes
> decoding code into a generic `here are my callbacks, please decode this
> instruction stream for me' type thing?
> 
> All I want for hw_breakpoint is to know whether an instruction is a load or
> a store, but even for that it looks like I'll need to duplicate a lot of
> stuff.

Note, I'm currently waiting on Leif to repost his opcodes.h before I
repost my instration-swabbing additions on top of it, since the swabbing
stuff seems to be strictly non-urgent.

Cheers
---Dave