Re: interesting line in process.c

From Dan Malek:

Paul Mackerras wrote:

quoted

Which brings up another question that I have been meaning to ask: what
is the rationale for adding the dbcr0/1 fields to the ptrace struct
for 4xx?

I dunno.  They have also been moving around during the 4xx port.
I just put them where the folks that send the patches have them.
I'll take a look at this since gdb is currently broken on 4xx.
They have to be context switched, and maybe someone though gdb should
have access to them.....

I bumped into this when I was looking at adding 74xx IABR/DABR support
for hardware breakpoints under gdb.
(see http://lists.linuxppc.org/linuxppc-dev/200108/msg00249.html)

But to really support the 405 (or booke) all 11 (or 12 for booke)
debug breakpoint registers should to be accessible to gdb.

i386 defines debugreg[8] in the thread_struct and gives ptrace access
to it with special restrictions.

I would suggest ppc do the same thing and define a single debug array
in thread_struct which contains the processor specific debug registers
needed to support gdb's use of hardware breakpoints.  New ptrace
numbers (offsets) will need to be defined to access this array.

Ed.Swarthout@motorola.com

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