diff options
Diffstat (limited to 'Documentation/trace/fprobetrace.rst')
| -rw-r--r-- | Documentation/trace/fprobetrace.rst | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst index 8e9bebcf0a..e35e6b18df 100644 --- a/Documentation/trace/fprobetrace.rst +++ b/Documentation/trace/fprobetrace.rst @@ -59,8 +59,12 @@ Synopsis of fprobe-events and bitfield are supported. (\*1) This is available only when BTF is enabled. - (\*2) only for the probe on function entry (offs == 0). - (\*3) only for return probe. + (\*2) only for the probe on function entry (offs == 0). Note, this argument access + is best effort, because depending on the argument type, it may be passed on + the stack. But this only support the arguments via registers. + (\*3) only for return probe. Note that this is also best effort. Depending on the + return value type, it might be passed via a pair of registers. But this only + accesses one register. (\*4) this is useful for fetching a field of data structures. (\*5) "u" means user-space dereference. |