[PATCH] perf: arm_pmuv3: Zero initialize hw_id branch stack field

[Will Deacon]

On Fri, Aug 07, 2026 at 01:18:59PM +0100, James Clark wrote:
> 
> 
> On 07/08/2026 11:44, Anshuman Khandual wrote:
> > On 07/08/26 2:44 PM, James Clark wrote:
> > > PERF_SAMPLE_BRANCH_HW_INDEX is supported by BRBE so hw_id is passed to
> > > userspace, but it's never set by the BRBE driver. Zero initialize it as
> > > it should be according to the docs:
> > > 
> > >     * For the architectures whose raw branch records are
> > >     * already stored in age order, the hw_idx should be 0.
> > 
> > The in code documentation while defining perf_branch_stack.
> > Probably a good idea to specify the same above.
> > 
> >   * For the architectures whose raw branch records are
> >   * already stored in age order, the hw_idx should be 0.
> >   */
> > struct perf_branch_stack {
> > 	u64				nr;
> > 	u64				hw_idx;
> > 	struct perf_branch_entry	entries[];
> > };
> > 
> 
> I found it easily enough. I wouldn't want to put the same comment in two
> places and risk one of them going stale. And if I take it away from one
> place and move it to the struct then it's just missing from somewhere else
> instead. So I think I'd rather leave this one.

Yup, I've queued it as-is.

Cheers,

Will