From 9d77db3c730780c8ef5ccd4b66403ff5675cfe4e Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 13 May 2024 10:30:14 +0000
Subject: [PATCH] modify sin led gpio
---
kernel/Documentation/trace/uprobetracer.rst | 31 ++++++++++++++++++++++---------
1 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/kernel/Documentation/trace/uprobetracer.rst b/kernel/Documentation/trace/uprobetracer.rst
index d082281..a8e5938 100644
--- a/kernel/Documentation/trace/uprobetracer.rst
+++ b/kernel/Documentation/trace/uprobetracer.rst
@@ -18,12 +18,17 @@
However unlike kprobe-event tracer, the uprobe event interface expects the
user to calculate the offset of the probepoint in the object.
+You can also use /sys/kernel/debug/tracing/dynamic_events instead of
+uprobe_events. That interface will provide unified access to other
+dynamic events too.
+
Synopsis of uprobe_tracer
-------------------------
::
p[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a uprobe
r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] : Set a return uprobe (uretprobe)
+ p[:[GRP/]EVENT] PATH:OFFSET%return [FETCHARGS] : Set a return uprobe (uretprobe)
-:[GRP/]EVENT : Clear uprobe or uretprobe event
GRP : Group name. If omitted, "uprobes" is the default value.
@@ -31,6 +36,7 @@
on PATH+OFFSET.
PATH : Path to an executable or a library.
OFFSET : Offset where the probe is inserted.
+ OFFSET%return : Offset where the return probe is inserted.
FETCHARGS : Arguments. Each probe can have up to 128 args.
%REG : Fetch register REG
@@ -38,16 +44,19 @@
@+OFFSET : Fetch memory at OFFSET (OFFSET from same file as PATH)
$stackN : Fetch Nth entry of stack (N >= 0)
$stack : Fetch stack address.
- $retval : Fetch return value.(*)
+ $retval : Fetch return value.(\*1)
$comm : Fetch current task comm.
- +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
+ +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3)
+ \IMM : Store an immediate value to the argument.
NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
(u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types
(x8/x16/x32/x64), "string" and bitfield are supported.
- (*) only for return probe.
- (**) this is useful for fetching a field of data structures.
+ (\*1) only for return probe.
+ (\*2) this is useful for fetching a field of data structures.
+ (\*3) Unlike kprobe event, "u" prefix will just be ignored, becuse uprobe
+ events can access only user-space memory.
Types
-----
@@ -69,10 +78,9 @@
Event Profiling
---------------
-You can check the total number of probe hits and probe miss-hits via
-/sys/kernel/debug/tracing/uprobe_profile.
-The first column is event name, the second is the number of probe hits,
-the third is the number of probe miss-hits.
+You can check the total number of probe hits per event via
+/sys/kernel/debug/tracing/uprobe_profile. The first column is the filename,
+the second is the event name, the third is the number of probe hits.
Usage examples
--------------
@@ -149,10 +157,15 @@
# echo 1 > events/uprobes/enable
-Lets disable the event after sleeping for some time.
+Lets start tracing, sleep for some time and stop tracing.
::
+ # echo 1 > tracing_on
# sleep 20
+ # echo 0 > tracing_on
+
+Also, you can disable the event by::
+
# echo 0 > events/uprobes/enable
And you can see the traced information via /sys/kernel/debug/tracing/trace.
--
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