On 2013/6/21 2:31, Tom Zanussi wrote:
> Add support for SOFT_DISABLE to syscall events.
>
> The original SOFT_DISABLE patches didn't add support for soft disable
> of syscall events; this adds it and paves the way for future patches
> allowing triggers to be added to syscall events, since triggers are
> built on top of SOFT_DISABLE.
>
> Because the trigger and SOFT_DISABLE bits are attached to the
> ftrace_event_file associated with the event, pointers to the
> ftrace_event_files associated with the event are added to the syscall
> metadata entry for the event.
>
> Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
> ---
> include/linux/syscalls.h | 2 ++
> include/trace/syscall.h | 5 +++++
> kernel/trace/trace_syscalls.c | 28 ++++++++++++++++++++++++----
> 3 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 4147d70..b4c2afa 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -158,6 +158,8 @@ extern struct trace_event_functions
> exit_syscall_print_funcs;
> .args = nb ? args_##sname : NULL, \
> .enter_event = &event_enter_##sname, \
> .exit_event = &event_exit_##sname, \
> + .enter_file = NULL, /* Filled in at boot */ \
> + .exit_file = NULL, /* Filled in at boot */ \
> .enter_fields =
> LIST_HEAD_INIT(__syscall_meta_##sname.enter_fields), \
> }; \
> static struct syscall_metadata __used \
> diff --git a/include/trace/syscall.h b/include/trace/syscall.h
> index fed853f..ba24d3a 100644
> --- a/include/trace/syscall.h
> +++ b/include/trace/syscall.h
> @@ -19,6 +19,8 @@
> * @enter_fields: list of fields for syscall_enter trace event
> * @enter_event: associated syscall_enter trace event
> * @exit_event: associated syscall_exit trace event
> + * @enter_file: associated syscall_enter ftrace event file
> + * @exit_file: associated syscall_exit ftrace event file
> */
> struct syscall_metadata {
> const char *name;
> @@ -30,6 +32,9 @@ struct syscall_metadata {
>
> struct ftrace_event_call *enter_event;
> struct ftrace_event_call *exit_event;
> +
> + struct ftrace_event_file *enter_file;
> + struct ftrace_event_file *exit_file;
> };
I doubt this could work correctly.
struct ftrace_event_file is allocated dynamically, there could
have many ftrace_event_file in there, associated with different trace_array,
it means there may have many ftrace_event_file linked with same
syscall_metadata.
The enter_file/exit_file pointer of syscall_metadata will be override if another
ftrace_event_file registered in some other trace_array.
Perhaps we could use simple list_head in here, which link with all registered
ftrace_event_file.
Oleg use "struct event_file_link" for trace_kprobe, the structure could be
reuse in here.
struct event_file_link {
struct ftrace_event_file *file;
struct list_head list;
};
struct syscall_metadata {
const char *name;
int syscall_nr;
int nb_args;
const char **types;
const char **args;
struct list_head enter_fields;
struct ftrace_event_call *enter_event;
struct ftrace_event_call *exit_event;
struct list_head enter_files;
struct list_head exit_files;
};
.jovi
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