linux-stable/Documentation/trace
Masami Hiramatsu (Google) 16cc222026 tracing/probes: Add symstr type for dynamic events
[ Upstream commit b26a124cbf ]

Add 'symstr' type for storing the kernel symbol as a string data
instead of the symbol address. This allows us to filter the
events by wildcard symbol name.

e.g.
  # echo 'e:wqfunc workqueue.workqueue_execute_start symname=$function:symstr' >> dynamic_events
  # cat events/eprobes/wqfunc/format
  name: wqfunc
  ID: 2110
  format:
  	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
  	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
  	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
  	field:int common_pid;	offset:4;	size:4;	signed:1;

  	field:__data_loc char[] symname;	offset:8;	size:4;	signed:1;

  print fmt: " symname=\"%s\"", __get_str(symname)

Note that there is already 'symbol' type which just change the
print format (so it still stores the symbol address in the tracing
ring buffer.) On the other hand, 'symstr' type stores the actual
"symbol+offset/size" data as a string.

Link: https://lore.kernel.org/all/166679930847.1528100.4124308529180235965.stgit@devnote3/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Stable-dep-of: 66bcf65d6c ("tracing/probes: Fix to avoid double count of the string length on the array")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-03 10:23:54 +02:00
..
coresight perf tools changes for v6.1: 1st batch 2022-10-11 15:02:25 -07:00
postprocess
rv
boottime-trace.rst
events-kmem.rst
events-msr.rst
events-nmi.rst
events-power.rst
events.rst
fprobe.rst
ftrace-design.rst
ftrace-uses.rst
ftrace.rst attr: use consistent sgid stripping checks 2023-03-03 11:52:25 +01:00
function-graph-fold.vim
hisi-ptt.rst
histogram-design.rst
histogram.rst tracing/histogram: Update document for KEYS_MAX size 2022-10-18 15:41:56 -06:00
hwlat_detector.rst
index.rst
intel_th.rst
kprobes.rst kprobes: kretprobe events missing on 2-core KVM guest 2023-01-04 11:28:58 +01:00
kprobetrace.rst tracing/probes: Add symstr type for dynamic events 2023-08-03 10:23:54 +02:00
mmiotrace.rst
osnoise-tracer.rst
ring-buffer-design.rst
stm.rst
sys-t.rst
timerlat-tracer.rst
tracepoint-analysis.rst
tracepoints.rst
uprobetracer.rst
user_events.rst