interesting line in process.c

Daniel Jacobowitz dmj+ at
Sun Oct 14 03:14:02 EST 2001

On Sat, Oct 13, 2001 at 09:56:32PM +1000, Paul Mackerras wrote:
> I'm intrigued by this line, line 276 in arch/ppc/kernel/process.c in
> linuxppc_2_4_devel:
> #if defined(CONFIG_4xx) && defined(DCRN_PLB0_BEAR) && defined(DCRN_PLB0_BEAR)
> When could we have DCRN_PLB0_BEAR defined but DCRN_PLB0_BEAR not? :)
> Could it ever be defined if CONFIG_4xx was not defined?
> 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?
> Since struct ptrace is part of the kernel/user ABI, I prefer not to
> change it unless it is absolutely necessary.  Could the dbcr0/1 fields
> go in the thread_struct instead?  Where and how are they used?

Well, I don't know anything about the 4xx, so this might not be
reasonable - but could they be used in setting hardware breakpoints?

Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer

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