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    Subject[PATCH v2 6/7] perf cs-etm: Detect pid in VMID for kernel running at EL2
    Date
    From: Suzuki K Poulose <suzuki.poulose@arm.com>

    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 <mike.leach@linaro.org>
    Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
    Cc: Al Grant <al.grant@arm.com>
    Co-developed-by: Leo Yan <leo.yan@linaro.org>
    Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
    Signed-off-by: Leo Yan <leo.yan@linaro.org>
    ---
    .../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 <mathieu.poirier@linaro.org>
    */

    +#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)
    + 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):
    + case BIT(ETM_OPT_CTXTID2):
    + if (elem->context.vmid_valid)
    + tid = elem->context.vmid;
    + break;
    + default:
    + break;
    + }
    +
    + if (tid == -1)
    return OCSD_RESP_CONT;

    - tid = elem->context.context_id;
    if (cs_etm__etmq_set_tid(etmq, tid, trace_chan_id))
    return OCSD_RESP_FATAL_SYS_ERR;

    --
    2.25.1
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