tracing/syscalls: Add filtering support

This patchset adds filtering support for syscall events

For syscall enter events, we can do filtering on syscall parameters, and for exit events, filter on syscall return value.

For example, we set 'mode == 0666' (0666 == 0x1b6) to sys_enter_open, and set 'ret == 0' to sys_exit_open, and here's the output:

 # echo 'mode == 0666' > events/syscalls/sys_enter_open
 # echo 'ret == 0' > events/syscalls/sys_exit_open
 # echo 1 > events/syscalls/sys_enter_open
 # echo 1 > events/syscalls/sys_exit_open
 # cat trace
 ...
   modprobe-3084 [001] 117.463140: sys_open(filename: 917d3e8, flags: 0, mode: 1b6) 
   modprobe-3084 [001] 117.463176: sys_open -> 0x0
       less-3086 [001] 117.510455: sys_open(filename: 9c6bdb8, flags: 8000, mode: 1b6) 
   sendmail-2574 [001] 122.145840: sys_open(filename: b807a365, flags: 0, mode: 1b6) 
 ...

[PATCH 1/5] tracing/syscalls: Fix fields format for enter events [PATCH 2/5] tracing/syscalls: Add fields format for exit events [PATCH 3/5] tracing/events: Add ftrace_event_call param to define_fields() [PATCH 4/5] tracing/events: Add trace_define_common_fields() [PATCH 5/5] tracing/syscalls: Add filtering support

---
 include/linux/ftrace_event.h  |   15 ++----
 include/linux/syscalls.h      |   19 +++++--
 include/trace/ftrace.h        |   11 ++---
 include/trace/syscall.h       |   13 ++++-
 kernel/trace/trace_events.c   |   29 +++++++++-
 kernel/trace/trace_export.c   |   13 ++---
 kernel/trace/trace_syscalls.c |  120 +++++++++++++++++++++++++++++++----------
 7 files changed, 156 insertions(+), 64 deletions(-)