• Peter Zijlstra's avatar
    ftrace: Rework event_create_dir() · 04ae87a5
    Peter Zijlstra authored
    Rework event_create_dir() to use an array of static data instead of
    function pointers where possible.
    
    The problem is that it would call the function pointer on module load
    before parse_args(), possibly even before jump_labels were initialized.
    Luckily the generated functions don't use jump_labels but it still seems
    fragile. It also gets in the way of changing when we make the module map
    executable.
    
    The generated function are basically calling trace_define_field() with a
    bunch of static arguments. So instead of a function, capture these
    arguments in a static array, avoiding the function call.
    
    Now there are a number of cases where the fields are dynamic (syscall
    arguments, kprobes and uprobes), in which case a static array does not
    work, for these we preserve the function call. Luckily all these cases
    are not related to modules and so we can retain the function call for
    them.
    
    Also fix up all broken tracepoint definitions that now generate a
    compile error.
    Tested-by: default avatarAlexei Starovoitov <ast@kernel.org>
    Tested-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: https://lkml.kernel.org/r/20191111132458.342979914@infradead.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    04ae87a5
trace_events.h 22.2 KB