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authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-04 11:05:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-04 11:05:48 -0700
commit228dfe98a313f6b6bff5da8b2c5e650e297ebf1a (patch)
tree501dc44c2453743eb2298fe23d6cdd0b5e91b2c2 /Documentation/trace/coresight/coresight.rst
parent798cd57cd5f871452461746032cf6ee50b0fd69a (diff)
parentb5276c924497705ca927ad85a763c37f2de98349 (diff)
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Merge tag 'char-misc-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc driver updates from Greg KH: "Here is the large set of char and misc and other driver subsystem changes for 6.0-rc1. Highlights include: - large set of IIO driver updates, additions, and cleanups - new habanalabs device support added (loads of register maps much like GPUs have) - soundwire driver updates - phy driver updates - slimbus driver updates - tiny virt driver fixes and updates - misc driver fixes and updates - interconnect driver updates - hwtracing driver updates - fpga driver updates - extcon driver updates - firmware driver updates - counter driver update - mhi driver fixes and updates - binder driver fixes and updates - speakup driver fixes All of these have been in linux-next for a while without any reported problems" * tag 'char-misc-6.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (634 commits) drivers: lkdtm: fix clang -Wformat warning char: remove VR41XX related char driver misc: Mark MICROCODE_MINOR unused spmi: trace: fix stack-out-of-bound access in SPMI tracing functions dt-bindings: iio: adc: Add compatible for MT8188 iio: light: isl29028: Fix the warning in isl29028_remove() iio: accel: sca3300: Extend the trigger buffer from 16 to 32 bytes iio: fix iio_format_avail_range() printing for none IIO_VAL_INT iio: adc: max1027: unlock on error path in max1027_read_single_value() iio: proximity: sx9324: add empty line in front of bullet list iio: magnetometer: hmc5843: Remove duplicate 'the' iio: magn: yas530: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros iio: magnetometer: ak8974: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros iio: light: veml6030: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros iio: light: vcnl4035: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros iio: light: vcnl4000: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() macros iio: light: tsl2591: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() iio: light: tsl2583: Use DEFINE_RUNTIME_DEV_PM_OPS and pm_ptr() iio: light: isl29028: Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr() iio: light: gp2ap002: Switch to DEFINE_RUNTIME_DEV_PM_OPS and pm_ptr() ...
Diffstat (limited to 'Documentation/trace/coresight/coresight.rst')
-rw-r--r--Documentation/trace/coresight/coresight.rst58
1 files changed, 52 insertions, 6 deletions
diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst
index a15571d96cc8..4a71ea6cb390 100644
--- a/Documentation/trace/coresight/coresight.rst
+++ b/Documentation/trace/coresight/coresight.rst
@@ -130,7 +130,7 @@ Misc:
Device Tree Bindings
--------------------
-See Documentation/devicetree/bindings/arm/coresight.txt for details.
+See Documentation/devicetree/bindings/arm/arm,coresight-\*.yaml for details.
As of this writing drivers for ITM, STMs and CTIs are not provided but are
expected to be added as the solution matures.
@@ -339,7 +339,8 @@ Preference is given to the former as using the sysFS interface
requires a deep understanding of the Coresight HW. The following sections
provide details on using both methods.
-1) Using the sysFS interface:
+Using the sysFS interface
+~~~~~~~~~~~~~~~~~~~~~~~~~
Before trace collection can start, a coresight sink needs to be identified.
There is no limit on the amount of sinks (nor sources) that can be enabled at
@@ -446,7 +447,8 @@ wealth of possibilities that coresight provides.
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
-2) Using perf framework:
+Using perf framework
+~~~~~~~~~~~~~~~~~~~~
Coresight tracers are represented using the Perf framework's Performance
Monitoring Unit (PMU) abstraction. As such the perf framework takes charge of
@@ -495,7 +497,11 @@ More information on the above and other example on how to use Coresight with
the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
repository [#third]_.
-2.1) AutoFDO analysis using the perf tools:
+Advanced perf framework usage
+-----------------------------
+
+AutoFDO analysis using the perf tools
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
perf can be used to record and analyze trace of programs.
@@ -513,7 +519,8 @@ The --itrace option controls the type and frequency of synthesized events
Note that only 64-bit programs are currently supported - further work is
required to support instruction decode of 32-bit Arm programs.
-2.2) Tracing PID
+Tracing PID
+~~~~~~~~~~~
The kernel can be built to write the PID value into the PE ContextID registers.
For a kernel running at EL1, the PID is stored in CONTEXTIDR_EL1. A PE may
@@ -547,7 +554,7 @@ wants to trace PIDs for both host and guest, the two configs "contextid1" and
Generating coverage files for Feedback Directed Optimization: AutoFDO
----------------------------------------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'perf inject' accepts the --itrace option in which case tracing data is
removed and replaced with the synthesized events. e.g.
@@ -578,6 +585,45 @@ sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tuto
Bubble sorting array of 30000 elements
5806 ms
+Config option formats
+~~~~~~~~~~~~~~~~~~~~~
+
+The following strings can be provided between // on the perf command line to enable various options.
+They are also listed in the folder /sys/bus/event_source/devices/cs_etm/format/
+
+.. list-table::
+ :header-rows: 1
+
+ * - Option
+ - Description
+ * - branch_broadcast
+ - Session local version of the system wide setting:
+ :ref:`ETM_MODE_BB <coresight-branch-broadcast>`
+ * - contextid
+ - See `Tracing PID`_
+ * - contextid1
+ - See `Tracing PID`_
+ * - contextid2
+ - See `Tracing PID`_
+ * - configid
+ - Selection for a custom configuration. This is an implementation detail and not used directly,
+ see :ref:`trace/coresight/coresight-config:Using Configurations in perf`
+ * - preset
+ - Override for parameters in a custom configuration, see
+ :ref:`trace/coresight/coresight-config:Using Configurations in perf`
+ * - sinkid
+ - Hashed version of the string to select a sink, automatically set when using the @ notation.
+ This is an internal implementation detail and is not used directly, see `Using perf
+ framework`_.
+ * - cycacc
+ - Session local version of the system wide setting: :ref:`ETMv4_MODE_CYCACC
+ <coresight-cycle-accurate>`
+ * - retstack
+ - Session local version of the system wide setting: :ref:`ETM_MODE_RETURNSTACK
+ <coresight-return-stack>`
+ * - timestamp
+ - Session local version of the system wide setting: :ref:`ETMv4_MODE_TIMESTAMP
+ <coresight-timestamp>`
How to use the STM module
-------------------------