On Wed, Nov 25, 2020 at 09:12:14PM +0100, Salvatore Bonaccorso wrote:
From: Leo Yan leo.yan@linaro.org
commit 95c6fe970a0160cb770c5dce9f80311b42d030c0 upstream.
If packet processing wants to know the packet is bound with which ETM version, it needs to access metadata to decide that based on metadata magic number; but we cannot simply to use CPU logic ID number as index to access metadata sequential array, especially when system have hotplugged off CPUs, the metadata array are only allocated for online CPUs but not offline CPUs, so the CPU logic number doesn't match with its index in the array.
This patch is to change tuple from traceID-CPU# to traceID-metadata, thus it can use the tuple to retrieve metadata pointer according to traceID.
For safe accessing metadata fields, this patch provides helper function cs_etm__get_cpu() which is used to return CPU number according to traceID; cs_etm_decoder__buffer_packet() is the first consumer for this helper function.
Signed-off-by: Leo Yan leo.yan@linaro.org Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Mike Leach mike.leach@linaro.org Cc: Namhyung Kim namhyung@kernel.org Cc: Robert Walker robert.walker@arm.com Cc: Suzuki K Poulouse suzuki.poulose@arm.com Cc: coresight ml coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20190129122842.32041-6-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com [Salvatore Bonaccorso: Adjust for context changes in tools/perf/util/cs-etm-decoder/cs-etm-decoder.c] Signed-off-by: Salvatore Bonaccorso carnil@debian.org
That's a fallout on my end. Should have said: This is for 4.19 specifically to be queued.
Background: in https://lore.kernel.org/stable/20201014135627.GA3698844@kroah.com/ 168200b6d6ea0cb5765943ec5da5b8149701f36a was queued up for v4.19.y but the prerequeisite commit was not included and so resulted in build failures with gcc 8.3.0.
The commit was later on reverted but in this thread it was asked to actually make it possible to compile the file as well with more recent gcc versions.
Those two patches to be applied in 4.19.y only pick up a backport of the rerequisite commit 95c6fe970a0160cb770c5dce9f80311b42d030c0 (PATCH 1) followed up by the cherry-pick of 168200b6d6ea0cb5765943ec5da5b8149701f36a again.
Regards, Salvatore