Re: O2 RM7000 Issues

[Sergey Rogozhkin <rogozhkin@niisi.msk.ru>]

> Big loud bell began ringing.  The RM7000 fetches and decodes multiple
> instructions in one go.  And just like the E9000 cores it does
> throw an exception if it doesn't like one of the opcodes even if that
> doesn't actually get executed.  The kernel has a workaround for this
> PMC-Sierra peculiarity (I call it a bug) but it's only being activated
> for E9000 platforms.

Are you really sure RM7000 has this bug? Workaround mentioned above 
breaks gcc signal frame unwinding mechanism: it search for sigcontext 
struct at fixed offset from signal trampoline.

And one another known RM7000 bug, maybe not taken into account by linux: 
errata 38. r4k_wait is not suitable for RM7000 on some systems. I don't 
know if "O2" is affected.

Sergey Rogozhkin