Re: Adding MIPS registers (was Re: [PATCH v2] Reset errno before PTRACE_PEEKUSER for MIPS DSP_CONTROL)

Paul Burton
2014-09-10T06:47:20Z

On Tue, Sep 09, 2014 at 09:39:22PM +0100, James Hogan wrote:
> > with the UFR
> > feature, so the register set presented will have to change dynamically,
> > according to that setting even for Linux targets.
>
> I have a feeling that UFR is currently unlikely to be enabled in Linux,
> due to subtleties with mode switches in multi-threaded processes
> requiring kernel support. Matthew or Paul (on CC) can probably confirm
> that.

Correct, UFR (along with UFE) is currently not enabled by Linux, and I'm
not aware of any need to deal with the pain involved in enabling it. There
is a need to switch mode across a whole process, which will need to be met
in some other way (the prctls in my internal branch, and hopefully the
same once upstream).

Paul