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Subject[GIT PULL 02/15] stm class: Document the stm_ftrace
From: Chunyan Zhang <>

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 <>
Signed-off-by: Alexander Shishkin <>
Documentation/trace/stm.txt | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
index 11cff47eec..0376575010 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.

+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.
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