diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-05-15 14:38:42 +0900 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-05-25 23:04:42 -0400 |
| commit | e65f7ae7f4da56622ecf8f1eaed333b9a13f9435 (patch) | |
| tree | 41eeedabb989b5c5fb0671213d15e40a45349e08 /kernel/trace/trace_probe.h | |
| parent | 88903c464321cdbc2d473c24cbf311f576cf05bc (diff) | |
tracing/probe: Support user-space dereference
Support user-space dereference syntax for probe event arguments
to dereference the data-structure or array in user-space.
The syntax is just adding 'u' before an offset value.
+|-u<OFFSET>(<FETCHARG>)
e.g. +u8(%ax), +u0(+0(%si))
For example, if you probe do_sched_setscheduler(pid, policy,
param) and record param->sched_priority, you can add new
probe as below;
p do_sched_setscheduler priority=+u0($arg3)
Note that kprobe event provides this and it doesn't change the
dereference method automatically because we do not know whether
the given address is in userspace or kernel on some archs.
So as same as "ustring", this is an option for user, who has to
carefully choose the dereference method.
Link: http://lkml.kernel.org/r/155789872187.26965.4468456816590888687.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_probe.h')
| -rw-r--r-- | kernel/trace/trace_probe.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index c7546e7ff8e2..42816358dd48 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -92,9 +92,11 @@ enum fetch_op { FETCH_OP_FOFFS, /* File offset: .immediate */ // Stage 2 (dereference) op FETCH_OP_DEREF, /* Dereference: .offset */ + FETCH_OP_UDEREF, /* User-space Dereference: .offset */ // Stage 3 (store) ops FETCH_OP_ST_RAW, /* Raw: .size */ FETCH_OP_ST_MEM, /* Mem: .offset, .size */ + FETCH_OP_ST_UMEM, /* Mem: .offset, .size */ FETCH_OP_ST_STRING, /* String: .offset, .size */ FETCH_OP_ST_USTRING, /* User String: .offset, .size */ // Stage 4 (modify) op |