Re: Make CoredumpAction use Task.getRegisterBanks()

[Phil Muldoon <pmuldoon at redhat dot com>]

Mark Wielaard wrote:
> Thanks. So this seems slightly different from how we do things with
> ptrace/proc where we can have multiple different register banks (for
> floating point, extended floating point and control/debug registers). We
> might be able to always just use the USR address space to get at all of
> those together in one go (I don't actually know why we don't do that, or
> why ptrace provides different ways to access the same register sets).
>
>   

Apologies for the delay in replying.

For the FP and fpxregs (which I am writing code for right now), I just 
take the entire register buffer and dump it wholesale into the 
appropriate note in the core file. For GP registers there are some 
cross-isa issues (mainly in PPC) that require the code to pick them 
individually, sort them into order, them populate them as part of 
another note, the elf_prstatus note. This is an important distinction as 
GP registers do not have their own separate note area in core files, but 
are part of the thread elf_prstatus note. That is why both raw memory 
banks, and getRegisterByName are needed.

> If we can match up the raw memory for each register bank between
> ptrace/proc and core files from Task that would be ideal. Then the Isa
> can just do the getRegisterByName() mapping. I'll watch your rewrite of
> the core file stuff and see if this makes things easier and clearer (I
> guess it will).
>   

The two requirements needed for core files are:

1) Access to the raw memory behind the register via a ByteBuffer
2) Access to a logical method of getting registers by name, like 
getRegisterByName()

Regards

Phil