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authorChunyan Zhang <chunyan.zhang@spreadtrum.com>2017-03-23 09:13:25 +0300
committerAlexander Shishkin <alexander.shishkin@linux.intel.com>2017-08-25 17:58:34 +0300
commit39fccd2fc33c95de8358451f58c52b9e4b828ddd (patch)
tree3da4185e41c4483b95eda9612a0dc12c759bef2a /Documentation/trace
parent71c488f32b071bfb5cfe9ddf682cd2e0c310c75d (diff)
downloadlinux-39fccd2fc33c95de8358451f58c52b9e4b828ddd.tar.xz
stm class: Document the stm_ftrace
This patch adds a description to the stm_ftrace device source, an interface for collecting Ftrace's function trace information via STM devices. Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/stm.txt13
1 files changed, 12 insertions, 1 deletions
diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
index 11cff47eecce..03765750104b 100644
--- a/Documentation/trace/stm.txt
+++ b/Documentation/trace/stm.txt
@@ -83,7 +83,7 @@ by writing the name of the desired stm device there, for example:
$ echo dummy_stm.0 > /sys/class/stm_source/console/stm_source_link
For examples on how to use stm_source interface in the kernel, refer
-to stm_console or stm_heartbeat drivers.
+to stm_console, stm_heartbeat or stm_ftrace drivers.
Each stm_source device will need to assume a master and a range of
channels, depending on how many channels it requires. These are
@@ -107,5 +107,16 @@ console in the STP stream, create a "console" policy entry (see the
beginning of this text on how to do that). When initialized, it will
consume one channel.
+stm_ftrace
+==========
+
+This is another "stm_source" device, once the stm_ftrace has been
+linked with an stm device, and if "function" tracer is enabled,
+function address and parent function address which Ftrace subsystem
+would store into ring buffer will be exported via the stm device at
+the same time.
+
+Currently only Ftrace "function" tracer is supported.
+
[1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html