Re: [PATCH 1/3] perf/x86/amd: AMD support for bp_len > HW_BREAKPOINT_LEN_8

Oleg Nesterov
2013-11-09T15:10:38Z

On 11/08, Frederic Weisbecker wrote:
>
> On Wed, Oct 02, 2013 at 11:11:06AM -0500, suravee.suthikulpanit@amd.com wrote:
> >
> > diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> > index d3f5c63..26609bb 100644
> > --- a/arch/x86/include/asm/cpufeature.h
> > +++ b/arch/x86/include/asm/cpufeature.h
> > @@ -170,6 +170,7 @@
> > #define X86_FEATURE_TOPOEXT (6*32+22) /* topology extensions CPUID leafs */
> > #define X86_FEATURE_PERFCTR_CORE (6*32+23) /* core performance counter extensions */
> > #define X86_FEATURE_PERFCTR_NB (6*32+24) /* NB performance counter extensions */
> > +#define X86_FEATURE_BPEXT (6*32+26) /* data breakpoint extension */
>
> Does this feature only work on data breakpoint or is instruction breakpoint
> address range supported as well?

IIRC, execute range is supported as well.

But. I can't look at the code now, but iirc this can't really work until
we fix the (already discussed) problems with bp_len && X86_BREAKPOINT_LEN_X.
IOW, we should not blame these patches if it doesn't work.

Oleg.