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authorChangbin Du <changbin.du@intel.com>2018-02-17 08:39:40 +0300
committerJonathan Corbet <corbet@lwn.net>2018-03-07 20:23:19 +0300
commit00b27da349b8b6b891f8eafb3873ee82b77a61d8 (patch)
tree3c034eaefd0796585386d2bd5456a1f48ba70b94 /Documentation/trace
parent263ee775747d730bf584b334820700d6200b8f86 (diff)
downloadlinux-00b27da349b8b6b891f8eafb3873ee82b77a61d8.tar.xz
trace doc: convert trace/uprobetracer.txt to rst format
This converts the plain text documentation to reStructuredText format and add it into Sphinx TOC tree. No essential content change. Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Changbin Du <changbin.du@intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/index.rst1
-rw-r--r--Documentation/trace/uprobetracer.rst (renamed from Documentation/trace/uprobetracer.txt)44
2 files changed, 27 insertions, 18 deletions
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index c8e2130a7318..353fb8a91ab2 100644
--- a/Documentation/trace/index.rst
+++ b/Documentation/trace/index.rst
@@ -10,3 +10,4 @@ Linux Tracing Technologies
ftrace
ftrace-uses
kprobetrace
+ uprobetracer
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.rst
index bf526a7c5559..98d3f692957a 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.rst
@@ -1,7 +1,8 @@
- Uprobe-tracer: Uprobe-based Event Tracing
- =========================================
+=========================================
+Uprobe-tracer: Uprobe-based Event Tracing
+=========================================
- Documentation written by Srikar Dronamraju
+:Author: Srikar Dronamraju
Overview
@@ -19,6 +20,8 @@ user to calculate the offset of the probepoint in the object.
Synopsis of uprobe_tracer
-------------------------
+::
+
p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
-:[GRP/]EVENT : Clear uprobe or uretprobe event
@@ -57,7 +60,7 @@ x86-64 uses x64).
String type is a special type, which fetches a "null-terminated" string from
user space.
Bitfield is another special type, which takes 3 parameters, bit-width, bit-
-offset, and container-size (usually 32). The syntax is;
+offset, and container-size (usually 32). The syntax is::
b<bit-width>@<bit-offset>/<container-size>
@@ -74,28 +77,28 @@ the third is the number of probe miss-hits.
Usage examples
--------------
* Add a probe as a new uprobe event, write a new definition to uprobe_events
-as below: (sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash)
+ as below (sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash)::
echo 'p /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
- * Add a probe as a new uretprobe event:
+ * Add a probe as a new uretprobe event::
echo 'r /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
- * Unset registered event:
+ * Unset registered event::
echo '-:p_bash_0x4245c0' >> /sys/kernel/debug/tracing/uprobe_events
- * Print out the events that are registered:
+ * Print out the events that are registered::
cat /sys/kernel/debug/tracing/uprobe_events
- * Clear all events:
+ * Clear all events::
echo > /sys/kernel/debug/tracing/uprobe_events
Following example shows how to dump the instruction pointer and %ax register
-at the probed text address. Probe zfree function in /bin/zsh:
+at the probed text address. Probe zfree function in /bin/zsh::
# cd /sys/kernel/debug/tracing/
# cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
@@ -103,24 +106,27 @@ at the probed text address. Probe zfree function in /bin/zsh:
# objdump -T /bin/zsh | grep -w zfree
0000000000446420 g DF .text 0000000000000012 Base zfree
- 0x46420 is the offset of zfree in object /bin/zsh that is loaded at
- 0x00400000. Hence the command to uprobe would be:
+0x46420 is the offset of zfree in object /bin/zsh that is loaded at
+0x00400000. Hence the command to uprobe would be::
# echo 'p:zfree_entry /bin/zsh:0x46420 %ip %ax' > uprobe_events
- And the same for the uretprobe would be:
+And the same for the uretprobe would be::
# echo 'r:zfree_exit /bin/zsh:0x46420 %ip %ax' >> uprobe_events
-Please note: User has to explicitly calculate the offset of the probe-point
-in the object. We can see the events that are registered by looking at the
-uprobe_events file.
+.. note:: User has to explicitly calculate the offset of the probe-point
+ in the object.
+
+We can see the events that are registered by looking at the uprobe_events file.
+::
# cat uprobe_events
p:uprobes/zfree_entry /bin/zsh:0x00046420 arg1=%ip arg2=%ax
r:uprobes/zfree_exit /bin/zsh:0x00046420 arg1=%ip arg2=%ax
-Format of events can be seen by viewing the file events/uprobes/zfree_entry/format
+Format of events can be seen by viewing the file events/uprobes/zfree_entry/format.
+::
# cat events/uprobes/zfree_entry/format
name: zfree_entry
@@ -139,16 +145,18 @@ Format of events can be seen by viewing the file events/uprobes/zfree_entry/form
print fmt: "(%lx) arg1=%lx arg2=%lx", REC->__probe_ip, REC->arg1, REC->arg2
Right after definition, each event is disabled by default. For tracing these
-events, you need to enable it by:
+events, you need to enable it by::
# echo 1 > events/uprobes/enable
Lets disable the event after sleeping for some time.
+::
# sleep 20
# echo 0 > events/uprobes/enable
And you can see the traced information via /sys/kernel/debug/tracing/trace.
+::
# cat trace
# tracer: nop