On Wed, Dec 12, 2007 at 11:44:14AM -0600, Chris Friesen wrote: > > Hi all, > > First, I'm not subscribed to the list so I'd appreciate being cc'd on any > replies. > > We have a project getting started with MIPS, and one of the things that > we're trying to bring in is some exception-handling code that logs > various information about the ways that apps fail. > > In particular, the guys working on this have asked for the STATUS, CAUSE, > BADVADDR, and FPC_EIR registers to be made available as part of struct > sigcontext so that they can determine exactly why the app is failing. > > Looking at include/asm-mips/sigcontext.h I can see that these registers > appear to be in the struct, but are either marked as "unused" or now have > different names. > > Am I correct that these registers are not currently exported to userspace > on a fault? If this is the case, why not? Does anyone have a patch to > enable this export? There used to be slots for badvaddr and cause. You'll have to ask Ralf why he decided to clobber them for DSP state, I don't remember :-) I suspect they may never have held useful information for you; we don't context switch them for userspace, so an intervening fault in kernel space or in another thread could change them. FPC_EIR is, unless I misremember, constant and read only. You can just read it. -- Daniel Jacobowitz CodeSourcery
