Re: [patch 00/11] Hardware Breakpoint interfaces

K.Prasad
2009-03-11T12:12:50Z

On Tue, Mar 10, 2009 at 02:46:55PM +0100, Ingo Molnar wrote:
>
> * prasad@linux.vnet.ibm.com <prasad@linux.vnet.ibm.com> wrote:
>
> > Hi Ingo,
>
> > Please find the revised set of patches that implement
> > Hardware Breakpoint (or watchpoint) registers and an
> > arch-specific implementation for x86/x86_64.
>
> General structure looks good, with a good deal of details
> that need to be addressed.
>

Thanks to Alan Stern for answering most of the questions....I am
pitching in to fill the gaps and do any re-write based on the
comments.

> Firstly, as far as i can see this should work on 32-bit too,
> correct?
>

Yes. It's been tested on 32-bit x86 all throughout.

> Secondly, what about other architectures - will they build just
> fine without any arch level glue code? kernel/hw_breakpoint.o
> get build unconditionally - without any benefit to non-x86 code.
> Perhaps an ARCH_HAS_HW_BREAKPOINTS Kconfig method would be
> useful to add.

The hardware breakpoint interfaces haven't been put under any CONFIG_
till now, but I think we should bring them under a new config, say
CONFIG_HW_BREAKPOINT. It would help create a dependancy for
CONFIG_KSYM_TRACER too.

>
> There's also a number of (small) style issues.
> kernel/hw_breakpoint.c and other new .c files dont comply to the
> customary comment style of:
>
> /*
> * Comment .....
> * ...... goes here:
> */
>
> also, the #include files section style should match that of
> arch/x86/mm/fault.c - it's a conflict-avoidance style.
>
> also, things like this:
>
> static struct notifier_block hw_breakpoint_exceptions_nb = {
> .notifier_call = hw_breakpoint_exceptions_notify,
> .priority = 0x7fffffff /* we need to be notified first */
> };
>
> should be:
>
> static struct notifier_block hw_breakpoint_exceptions_nb = {
> .notifier_call = hw_breakpoint_exceptions_notify,
> /* We need to be notified first: */
> .priority = 0x7fffffff,
> };
>
> Ingo

Sure, will look at the comment styling before I re-send the patchset.

Thanks,
K.Prasad