[PATCH] coresight: catu: Fix number of pages while using 64k pages
Suzuki K Poulose
suzuki.poulose at arm.com
Mon Jan 13 08:49:04 PST 2025
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 at os.amperecomputing.com>
>>> ---
>>> 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
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