Re: [PATCH v2 6/7] perf cs-etm: Detect pid in VMID for kernel running at EL2
From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: 2021-02-02 23:31:07
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On 2/2/21 4:38 PM, Leo Yan wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Al Grant <redacted> Co-developed-by: Leo Yan <redacted> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Leo Yan <redacted> --- .../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)
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 <suzuki.poulose@arm.com> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel