perf trace: Handle legacy syscalls tracepoints

Currently the code skips the first field with the expectation that it is 'nr'.
But older kernels do not have the 'nr' field:

    field:int nr;   offset:8;   size:4; signed:1;

Change perf-trace to drop the field if it exists after parsing the format file.

This fixes the off-by-one problem with older kernels (e.g., RHEL6). e.g,
perf-trace shows this for write:

  1.515 ( 0.006 ms): dd/4245 write(buf: 2</dev/pts/0>, count: 140733837536224       ) = 26

where 2 is really the fd, the huge number is really the buf address, etc.  With
this patch you get the more appropriate:

  1.813 ( 0.003 ms): dd/6330 write(fd: 2</dev/pts/0>, buf: 0x7fff22fc81f0, count: 25) = 25

Based-on-a-patch-by: David Ahern <[email protected]>
Acked-by: David Ahern <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions