When the kernel is running at EL2, the PID is stored in CONTEXTIDR_EL2.
So, tracing CONTEXTIDR_EL1 doesn't give us the pid of the process.
Thus we should trace the VMID with VMIDOPT set to trace CONTEXTIDR_EL2
instead of CONTEXTIDR_EL1. Given that we have an existing config
option "contextid" and this will be useful for tracing virtual machines
(when we get to support virtualization).
So instead, this patch extends option CTXTID with an extra bit
ETM_OPT_CTXTID2 (bit 15), thus on an EL2 kernel, we will have another
bit available for the perf tool: ETM_OPT_CTXTID is for kernel running in
EL1, ETM_OPT_CTXTID2 is used when kernel runs in EL2 with VHE enabled.
The tool must be backward compatible for users, i.e, "contextid" today
traces PID and that should remain the same; for this purpose, the perf
tool is updated to automatically set corresponding bit for the
"contextid" config, therefore, the user doesn't have to bother which EL
the kernel is running.
i.e, perf record -e cs_etm/contextid/u --
will always do the "pid" tracing, independent of the kernel EL.
The driver parses the format "contextid", which traces CONTEXTIDR_EL1
for ETM_OPT_CTXTID (on EL1 kernel) and traces CONTEXTIDR_EL2 for
ETM_OPT_CTXTID2 (on EL2 kernel).
Besides the enhancement for format "contexid", extra two formats are
introduced: "contextid1" and "contextid2". This considers to support
tracing both CONTEXTIDR_EL1 and CONTEXTIDR_EL2 when the kernel is
running at EL2. Finally, the PMU formats are defined as follow:
"contextid1": Available on both EL1 kernel and EL2 kernel. When the
kernel is running at EL1, "contextid1" enables the PID
tracing; when the kernel is running at EL2, this enables
tracing the PID of guest applications.
"contextid2": Only usable when the kernel is running at EL2. When
selected, enables PID tracing on EL2 kernel.
"contextid": Will be an alias for the option that enables PID
tracing. I.e,
contextid == contextid1, on EL1 kernel.
contextid == contextid2, on EL2 kernel.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Al Grant <al.grant@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[ Added two config formats: contextid1, contextid2 ]
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210206150833.42120-4-leo.yan@linaro.org
Link: https://lore.kernel.org/r/20210211172038.2483517-3-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In theory, the options should be arbitrary values and are neutral for
any ETM version; so far perf tool uses ETMv3.5/PTM ETMCR config bits
except for register's bit definitions, also uses as options.
This can introduce confusion, especially if we want to add a new option
but the new option is not supported by ETMv3.5/PTM ETMCR. But on the
other hand, we cannot change options since these options are generic
CoreSight PMU ABI.
For easier maintenance and avoid confusion, this patch refines the
comment to clarify perf options, and gives out the background info for
these bits are coming from ETMv3.5/PTM. Afterwards, we should take
these options as general knobs, and if there have any confliction with
ETMv3.5/PTM, should consider to define saperate macros for ETMv3.5/PTM
ETMCR config bits.
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20210206150833.42120-2-leo.yan@linaro.org
Link: https://lore.kernel.org/r/20210211172038.2483517-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Set the proper bit in the configuration register when contextID tracing
has been requested by user space. That way PE_CONTEXT elements are
generated by the tracers when a process is installed on a CPU.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Robert Walker <robert.walker@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The value passed into the perf.data file for the CONFIGR register in ETMv4
was incorrectly being set to the command line options/ETMv3 value.
Adds bit definitions and function to remap this value to the correct ETMv4
CONFIGR bit values for all selected options.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Return stack is a programmable option on some ETM and PTM hardware.
Adds the option flags to enable this from the perf event command line.
Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TraceID values have to be unique for all tracers and
consistent between drivers and user space. As such
introducing a central function to be used whenever a
traceID value is required.
The patch also account for data traceIDs, which are usually
I(N) + 1.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Perf is a well known and used tool for performance monitoring
and much more. A such it is an ideal candidate for integration
with coresight based HW tracing.
This patch introduces a PMU that represent a coresight tracer to
the Perf core.
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suzuki K Poulose