Messages in this thread | | | Date | Sat, 19 Sep 2009 09:17:12 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/2] tracing: Document HAVE_FTRACE_SYSCALLS needs |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Document the arch needed requirements to get the support for syscalls > tracing. > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Li Zefan <lizf@cn.fujitsu.com> > Cc: Masami Hiramatsu <mhiramat@redhat.com> > Cc: Jason Baron <jbaron@redhat.com> > Cc: Lai Jiangshan <laijs@cn.fujitsu.com> > Cc: Heiko Carstens <heiko.carstens@de.ibm.com> > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> > Cc: Paul Mundt <lethal@linux-sh.org> > --- > Documentation/trace/ftrace-design.txt | 11 ++++++++++- > 1 files changed, 10 insertions(+), 1 deletions(-) > > diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt > index 7003e10..04ab61c 100644 > --- a/Documentation/trace/ftrace-design.txt > +++ b/Documentation/trace/ftrace-design.txt > @@ -216,7 +216,16 @@ If you can't trace NMI functions, then skip this option. > HAVE_FTRACE_SYSCALLS > --------------------- > > -<details to be filled> > +You need very few things to get the syscalls tracing in an arch. > + > +- Have a NR_syscalls variable in <asm/unistd.h> that provides the number > + of syscalls supported by the arch. > +- Implement arch_syscall_addr() that resolves a syscall address from a > + syscall number. > +- Support the TIF_SYSCALL_TRACEPOINT thread flags > +- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace > + in the ptrace syscalls tracing path. > +- Tag this arch as HAVE_FTRACE_SYSCALLS.
HAVE_FTRACE_SYSCALLS is not actually used anywhere.
Ingo
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