Re: [PATCH] coresight: catu: Fix number of pages while using 64k pages

[Suzuki K Poulose]

On 10/01/2025 21:32, Ilkka Koskinen wrote:
> Hi Suzuko,
>
> On Fri, 10 Jan 2025, Suzuki K Poulose wrote:
> > On 09/01/2025 21:53, Ilkka Koskinen wrote:
> > > Trying to record a trace on kernel with 64k pages resulted in -ENOMEM.
> > > This happens due to a bug in calculating the number of table pages, 
> > > which
> > > returns zero. Fix the issue by rounding up.
> > >
> > > $ perf record --kcore -e cs_etm/@tmc_etr55,cycacc,branch_broadcast/k 
> > > --per-thread taskset --cpu-list 1 dd if=/dev/zero of=/dev/null
> > > failed to mmap with 12 (Cannot allocate memory)
> >
> > Needs a Fixes tag.
> >
> > Fixes : 8ed536b1e283 ("coresight: catu: Add support for scatter gather 
> > tables")
>
> That's a good point
>
> > > Signed-off-by: Ilkka Koskinen <ilkka@xxxxxxxxxxxxxxxxxxxxxx>
> > > ---
> > >   drivers/hwtracing/coresight/coresight-catu.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/ 
> > > hwtracing/coresight/coresight-catu.c
> > > index 275cc0d9f505..3378bb77e6b4 100644
> > > --- a/drivers/hwtracing/coresight/coresight-catu.c
> > > +++ b/drivers/hwtracing/coresight/coresight-catu.c
> > > @@ -269,7 +269,7 @@ catu_init_sg_table(struct device *catu_dev, int 
> > > node,
> > >        * Each table can address upto 1MB and we can have
> > >        * CATU_PAGES_PER_SYSPAGE tables in a system page.
> > >        */
> > > -    nr_tpages = DIV_ROUND_UP(size, SZ_1M) / CATU_PAGES_PER_SYSPAGE;
> > > +    nr_tpages = DIV_ROUND_UP(size, CATU_PAGES_PER_SYSPAGE * SZ_1M);
> > >       catu_table = tmc_alloc_sg_table(catu_dev, node, nr_tpages,
> > >                       size >> PAGE_SHIFT, pages);
> > >       if (IS_ERR(catu_table))
> >
> > Looks good to me, I will queue this later for v6.15.
> >
> > Suzuki
>
> Sounds great. Just to confirm, are you ok to add the fixes line or would 
> you prefer me to submit v2 with it?

No, not required. I have picked this up for v6.15, and will push it out
once v6.14-rc is out.

Suzuki


> Cheers, Ilkka