Messages in this thread Patch in this message | | | From | "Masami Hiramatsu (Google)" <> | Subject | [PATCH v3 07/10] docs: tracing: Update fprobe documentation | Date | Thu, 2 Feb 2023 00:56:55 +0900 |
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From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Update fprobe.rst for - the private entry_data argument - the return value of the entry handler - the nr_rethook_node field.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- Documentation/trace/fprobe.rst | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/Documentation/trace/fprobe.rst b/Documentation/trace/fprobe.rst index b64bec1ce144..40dd2fbce861 100644 --- a/Documentation/trace/fprobe.rst +++ b/Documentation/trace/fprobe.rst @@ -87,14 +87,16 @@ returns as same as unregister_ftrace_function(). The fprobe entry/exit handler ============================= -The prototype of the entry/exit callback function is as follows: +The prototype of the entry/exit callback function are as follows: .. code-block:: c - void callback_func(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs); + int entry_callback(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs, void *entry_data); -Note that both entry and exit callbacks have same ptototype. The @entry_ip is -saved at function entry and passed to exit handler. + void exit_callback(struct fprobe *fp, unsigned long entry_ip, struct pt_regs *regs, void *entry_data); + +Note that the @entry_ip is saved at function entry and passed to exit handler. +If the entry callback function returns !0, the corresponding exit callback will be cancelled. @fp This is the address of `fprobe` data structure related to this handler. @@ -113,6 +115,12 @@ saved at function entry and passed to exit handler. to use @entry_ip. On the other hand, in the exit_handler, the instruction pointer of @regs is set to the currect return address. +@entry_data + This is a local storage to share the data between entry and exit handlers. + This storage is NULL by default. If the user specify `exit_handler` field + and `entry_data_size` field when registering the fprobe, the storage is + allocated and passed to both `entry_handler` and `exit_handler`. + Share the callbacks with kprobes ================================
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