Scott Wood <scottw...@freescale.com> wrote on 2012/05/31 19:47:53: > > On 05/31/2012 04:56 AM, Joakim Tjernlund wrote: > > Abatron Support <supp...@abatron.ch> wrote on 2012/05/31 11:30:57: > >> > >> > >>> Abatron Support <supp...@abatron.ch> wrote on 2012/05/30 14:08:26: > >>>> > >>>>>> I have tested this briefly with BDI2000 on P2010(e500) and > >>>>>> it works for me. I don't know if there are any bad side effects, > >>>>>> therfore > >>>>>> this RFC. > >>>> > >>>>> We used to have MSR_DE surrounded by CONFIG_something > >>>>> to ensure it wasn't set under normal operation. IIRC, if MSR_DE > >>>>> is set, you will have problems with software debuggers that > >>>>> utilize the the debugging registers in the chip itself. You only want > >>>>> to force this to be set when using the BDI, not at other times. > >>>> > >>>> This MSR_DE is also of interest and used for software debuggers that > >>>> make use of the debug registers. Only if MSR_DE is set then debug > >>>> interrupts are generated. If a debug event leads to a debug interrupt > >>>> handled by a software debugger or if it leads to a debug halt handled > >>>> by a JTAG tool is selected with DBCR0_EDM / DBCR0_IDM. > >>>> > >>>> The "e500 Core Family Reference Manual" chapter "Chapter 8 > >>>> Debug Support" explains in detail the effect of MSR_DE. > >> > >>> So what is the verdict on this? I don't buy into Dan argument without some > >>> hard data. > >> > >> What I tried to mention is that handling the MSR_DE correct is not only > >> an emulator (JTAG debugger) requirement. Also a software debugger may > >> depend on a correct handled MSR_DE bit. > > > > Yes, that made sense to me too. How would SW debuggers work if the kernel > > keeps > > turning off MSR_DE first chance it gets? > > The kernel selectively enables MSR_DE when it wants to debug. I'm not > sure if anything will be bothered by leaving it on all the time. This > is something we need for virtualization as well, so a hypervisor can > debug the guest.
hmm, I read that as you as in favour of the patch? _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
