Previously when the incorrect binary was used for decode, Perf would
silently continue to generate incorrect samples. With OpenCSD 1.5.4 we
can enable consistency checks that do a best effort to detect a mismatch
in the image. When one is detected a warning is printed and sample
generation stops until the trace resynchronizes with a good part of the
image.
Reported-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Closes: https://lore.kernel.org/all/20240719092619.274730-1-gankulkarni@os.amperecomputing.com/
Signed-off-by: James Clark <james.clark@linaro.org>
---
tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index b78ef0262135..b85a8837bddc 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -685,9 +685,14 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
}
if (d_params->operation == CS_ETM_OPERATION_DECODE) {
+ int decode_flags = OCSD_CREATE_FLG_FULL_DECODER;
+#ifdef OCSD_OPFLG_N_UNCOND_DIR_BR_CHK
+ decode_flags |= OCSD_OPFLG_N_UNCOND_DIR_BR_CHK | OCSD_OPFLG_CHK_RANGE_CONTINUE |
+ ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK;
+#endif
if (ocsd_dt_create_decoder(decoder->dcd_tree,
decoder->decoder_name,
- OCSD_CREATE_FLG_FULL_DECODER,
+ decode_flags,
trace_config, &csid))
return -1;
--
2.34.1On 9/12/24 16:11, James Clark wrote:>
>
> Previously when the incorrect binary was used for decode, Perf would
> silently continue to generate incorrect samples. With OpenCSD 1.5.4 we
> can enable consistency checks that do a best effort to detect a mismatch
> in the image. When one is detected a warning is printed and sample
> generation stops until the trace resynchronizes with a good part of the
> image.
>
> Reported-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
> Closes: https://lore.kernel.org/all/20240719092619.274730-1-gankulkarni@os.amperecomputing.com/
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
> tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> index b78ef0262135..b85a8837bddc 100644
> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> @@ -685,9 +685,14 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
> }
>
> if (d_params->operation == CS_ETM_OPERATION_DECODE) {
> + int decode_flags = OCSD_CREATE_FLG_FULL_DECODER;
> +#ifdef OCSD_OPFLG_N_UNCOND_DIR_BR_CHK
> + decode_flags |= OCSD_OPFLG_N_UNCOND_DIR_BR_CHK | OCSD_OPFLG_CHK_RANGE_CONTINUE |
> + ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK;
> +#endif
Looks good to me.
Just one question: should the flag ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK be set
according to ETM version? E.g. it should be only set for ETMv4 or this is
fine for ETE as well.
Thanks,
Leo
> if (ocsd_dt_create_decoder(decoder->dcd_tree,
> decoder->decoder_name,
> - OCSD_CREATE_FLG_FULL_DECODER,
> + decode_flags,
> trace_config, &csid))
> return -1;
>
> --
> 2.34.1
>
On 13/09/2024 12:54, Leo Yan wrote:
> On 9/12/24 16:11, James Clark wrote:>
>>
>> Previously when the incorrect binary was used for decode, Perf would
>> silently continue to generate incorrect samples. With OpenCSD 1.5.4 we
>> can enable consistency checks that do a best effort to detect a mismatch
>> in the image. When one is detected a warning is printed and sample
>> generation stops until the trace resynchronizes with a good part of the
>> image.
>>
>> Reported-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
>> Closes:
>> https://lore.kernel.org/all/20240719092619.274730-1-gankulkarni@os.amperecomputing.com/
>> Signed-off-by: James Clark <james.clark@linaro.org>
>> ---
>> tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 7 ++++++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> index b78ef0262135..b85a8837bddc 100644
>> --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
>> @@ -685,9 +685,14 @@ cs_etm_decoder__create_etm_decoder(struct
>> cs_etm_decoder_params *d_params,
>> }
>>
>> if (d_params->operation == CS_ETM_OPERATION_DECODE) {
>> + int decode_flags = OCSD_CREATE_FLG_FULL_DECODER;
>> +#ifdef OCSD_OPFLG_N_UNCOND_DIR_BR_CHK
>> + decode_flags |= OCSD_OPFLG_N_UNCOND_DIR_BR_CHK |
>> OCSD_OPFLG_CHK_RANGE_CONTINUE |
>> + ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK;
>> +#endif
>
> Looks good to me.
>
> Just one question: should the flag ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK be set
> according to ETM version? E.g. it should be only set for ETMv4 or this is
> fine for ETE as well.
>
> Thanks,
> Leo
>
I asked Mike the same question about ETMv3 and he said none of the flags
overlap and it was ok to always pass them. So I assume the same applies
to ETE as well.
On 9/13/24 13:09, James Clark wrote: [...] >> Just one question: should the flag ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK be set >> according to ETM version? E.g. it should be only set for ETMv4 or this is >> fine for ETE as well. > > I asked Mike the same question about ETMv3 and he said none of the flags > overlap and it was ok to always pass them. So I assume the same applies > to ETE as well. Thanks for confirmation. This is my review tag: Reviewed-by: Leo Yan <leo.yan@arm.com>
© 2016 - 2026 Red Hat, Inc.