Re: [PATCH 1/5] perf: Add hardware breakpoint address mask

[Oleg Nesterov]

On 04/20, Jacob Shin wrote:
>
> On Sat, Apr 20, 2013 at 06:53:34PM +0200, Oleg Nesterov wrote:
> >
> > And does attr.bp_len "contribute" to the mask?
> >
> > I mean, if bp_len == X86_BREAKPOINT_LEN_8, does this mean that
> > bp_bp_addr_mask and (bp_bp_addr_mask | 7) have the same effect?
>
> Yes it has the same effect.

OK, thanks...

So this is the "natural" extension. Given that currently bp_addr
should be aligned, bp_len could be already bp_mask but I guess it
is too late to change this, so we need another field.

Hmm. Perhaps arch_has_hw_breakpoint_addr_mask(void) should be turned
into arch_validate_hw_breakpoint_addr_mask(bp) which should also
check that (bp_addr & bp_addr_mask) == 0. But I won't insist.

Oleg.

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