On 2/2/21 4:38 PM, Leo Yan wrote:
From: Suzuki K Poulose <[email protected]>

The PID of the task could be traced as VMID when the kernel is running
at EL2.  Teach the decoder to look for VMID when the CONTEXTIDR (Arm32)
or CONTEXTIDR_EL1 (Arm64) is invalid but we have a valid VMID.

Cc: Mike Leach <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Al Grant <[email protected]>
Co-developed-by: Leo Yan <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Signed-off-by: Leo Yan <[email protected]>
---
  .../perf/util/cs-etm-decoder/cs-etm-decoder.c | 32 ++++++++++++++++---
  1 file changed, 28 insertions(+), 4 deletions(-)

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 3f4bc4050477..fb2a163ff74e 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -6,6 +6,7 @@
   * Author: Mathieu Poirier <[email protected]>
   */
+#include <linux/coresight-pmu.h>
  #include <linux/err.h>
  #include <linux/list.h>
  #include <linux/zalloc.h>
@@ -491,13 +492,36 @@ cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,
                        const ocsd_generic_trace_elem *elem,
                        const uint8_t trace_chan_id)
  {
-       pid_t tid;
+       pid_t tid = -1;
+       u64 pid_fmt;
+       int ret;
- /* Ignore PE_CONTEXT packets that don't have a valid contextID */
-       if (!elem->context.ctxt_id_valid)
+       ret = cs_etm__get_pid_fmt(trace_chan_id, &pid_fmt);
+       if (ret)

Is this something we can cache in this function ? e.g,
        static u64 pid_fmt;

        if (!pid_pfmt)
                ret = cs_etm__get_pid_fmt(trace_chan_id, &pid_fmt);

As all the ETMs will be running at the same exception level.

+               return OCSD_RESP_FATAL_SYS_ERR;
+
+       /*
+        * Process the PE_CONTEXT packets if we have a valid contextID or VMID.
+        * If the kernel is running at EL2, the PID is traced in CONTEXTIDR_EL2
+        * as VMID, Bit ETM_OPT_CTXTID2 is set in this case.
+        */
+       switch (pid_fmt) {
+       case BIT(ETM_OPT_CTXTID):
+               if (elem->context.ctxt_id_valid)
+                       tid = elem->context.context_id;
+               break;
+       case BIT(ETM_OPT_CTXTID2) | BIT(ETM_OPT_CTXTID):

I would rather fix the cs_etm__get_pid_fmt() to return either of these
as commented. i.e, ETM_OPT_CTXTID or ETM_OPT_CTXTID2. Thus we don't
need the this case.


With the above two addressed:

Reviewed-by: Suzuki K Poulose <[email protected]>

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