> in change history of this file i am able to see KSEG0
> removed only for arch/mips64/lib/watch.S...
The hw takes physical addresses, so using a a virtual address as
argument >for __watch_set seemed to be stupid anyway. The hw
takes a physical address and the conversion is best done in C
The whole watch stuff in the the kernel is pretty much an ad-hoc
which I did create to debug a stack overflow. I'm sure if
going to use it you'll find problems. For userspace for example
have to switch the watch register when switching the MMU context
each process gets it's own virtual watch register.
Beyond that there
are at least two different formats of watch registers implemented
actual silicon, the original R4000-style and the MIPS32/MIPS64
watch registers and the kernel's watch code only know the R4000
my cpu manual ( IDT RC32334) talks about two watch registers
CP0_IWATCH and CP0_DWATCH where it is required to just put desired
VIRTUAL( bits 2--31) addresses to be watched , there is no mention
of CP0_WATCHLO and CP0_WATCHHI .
additionally i guees for userspace virtual watch register problem,
the hardware takes care of all , i just need to specify my virual
address this is what i understand from my manual.
and one more problem i face when i try to debug a mysterious page
fault problem, that i get my watch exception but after page fault
..hence I can't really debug , shouldn't the priority of watch
exceptions should be higher than atleast instruction fetch
exception.? or the scope of debugging by watch exception is
limited by design.....