Re: [PATCH v3 6/8] perf cs-etm: Add helper cs_etm__get_pid_fmt()

Mathieu Poirier
2021-02-08T20:33:36Z

On Sat, Feb 06, 2021 at 11:08:31PM +0800, Leo Yan wrote:
> This patch adds helper function cs_etm__get_pid_fmt(), by passing
> parameter "traceID", it returns the PID format.
>
> Signed-off-by: Leo Yan <leo.yan@linaro.org>

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> ---
> tools/perf/util/cs-etm.c | 42 ++++++++++++++++++++++++++++++++++++++++
> tools/perf/util/cs-etm.h | 1 +
> 2 files changed, 43 insertions(+)
>
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index a2a369e2fbb6..b9c1d329a7f1 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/bitops.h>
> +#include <linux/coresight-pmu.h>
> #include <linux/err.h>
> #include <linux/kernel.h>
> #include <linux/log2.h>
> @@ -156,6 +157,47 @@ int cs_etm__get_cpu(u8 trace_chan_id, int *cpu)
> return 0;
> }
>
> +/*
> + * The returned PID format is presented by two bits:
> + *
> + * Bit ETM_OPT_CTXTID: CONTEXTIDR or CONTEXTIDR_EL1 is traced;
> + * Bit ETM_OPT_CTXTID2: CONTEXTIDR_EL2 is traced.
> + *
> + * It's possible that the two bits ETM_OPT_CTXTID and ETM_OPT_CTXTID2
> + * are enabled at the same time when the session runs on an EL2 kernel.
> + * This means the CONTEXTIDR_EL1 and CONTEXTIDR_EL2 both will be
> + * recorded in the trace data, the tool will selectively use
> + * CONTEXTIDR_EL2 as PID.
> + */
> +int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt)
> +{
> + struct int_node *inode;
> + u64 *metadata, val;
> +
> + inode = intlist__find(traceid_list, trace_chan_id);
> + if (!inode)
> + return -EINVAL;
> +
> + metadata = inode->priv;
> +
> + if (metadata[CS_ETM_MAGIC] == __perf_cs_etmv3_magic) {
> + val = metadata[CS_ETM_ETMCR];
> + /* CONTEXTIDR is traced */
> + if (val & BIT(ETM_OPT_CTXTID))
> + *pid_fmt = BIT(ETM_OPT_CTXTID);
> + } else {
> + val = metadata[CS_ETMV4_TRCCONFIGR];
> + /* CONTEXTIDR_EL2 is traced */
> + if (val & (BIT(ETM4_CFG_BIT_VMID) | BIT(ETM4_CFG_BIT_VMID_OPT)))
> + *pid_fmt = BIT(ETM_OPT_CTXTID2);
> + /* CONTEXTIDR_EL1 is traced */
> + else if (val & BIT(ETM4_CFG_BIT_CTXTID))
> + *pid_fmt = BIT(ETM_OPT_CTXTID);
> + }
> +
> + return 0;
> +}
> +
> void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
> u8 trace_chan_id)
> {
> diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> index 4ad925d6d799..7cc3bba0017d 100644
> --- a/tools/perf/util/cs-etm.h
> +++ b/tools/perf/util/cs-etm.h
> @@ -173,6 +173,7 @@ struct cs_etm_packet_queue {
> int cs_etm__process_auxtrace_info(union perf_event *event,
> struct perf_session *session);
> int cs_etm__get_cpu(u8 trace_chan_id, int *cpu);
> +int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt);
> int cs_etm__etmq_set_tid(struct cs_etm_queue *etmq,
> pid_t tid, u8 trace_chan_id);
> bool cs_etm__etmq_is_timeless(struct cs_etm_queue *etmq);
> --
> 2.25.1