| Message ID | 50dd0fedb50e3a56ff8f25c44098db3e2a2d6374.1418146300.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Michael Ellerman |
| Headers | show |
On Tue, 2014-12-09 at 23:04 +0530, Naveen N. Rao wrote: > Use symbol table lookups by default if DWARF is not necessary, since > powerpc ABIv2 encodes local entry points in the symbol table and the > function entry address in DWARF may not be appropriate for kprobes, > as described here: > https://sourceware.org/bugzilla/show_bug.cgi?id=17638 Needs a better changelog. > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > index 174c22e..adcdbd2 100644 > --- a/tools/perf/util/probe-event.c > +++ b/tools/perf/util/probe-event.c > @@ -2382,6 +2382,14 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev, > } > } > > +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 > + if (!perf_probe_event_need_dwarf(pev)) { > + ret = find_probe_trace_events_from_map(pev, tevs, max_tevs, target); > + if (ret > 0) > + return ret; /* Found in symbol table */ > + } > +#endif And should be in an arch helper, not a big powerpc wart dropped in the middle of the generic code. cheers
On 2014/12/10 09:17PM, Michael Ellerman wrote: > On Tue, 2014-12-09 at 23:04 +0530, Naveen N. Rao wrote: > > Use symbol table lookups by default if DWARF is not necessary, since > > powerpc ABIv2 encodes local entry points in the symbol table and the > > function entry address in DWARF may not be appropriate for kprobes, > > as described here: > > https://sourceware.org/bugzilla/show_bug.cgi?id=17638 > > Needs a better changelog. Ok. Will add, but to elaborate quickly: DWARF will only include the entire function in low_pc/entry_pc and high_pc. It can't indicate the local entry point. Hence, we need to use the symbol table instead of DWARF on ABIv2. > > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > > index 174c22e..adcdbd2 100644 > > --- a/tools/perf/util/probe-event.c > > +++ b/tools/perf/util/probe-event.c > > @@ -2382,6 +2382,14 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev, > > } > > } > > > > +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 > > + if (!perf_probe_event_need_dwarf(pev)) { > > + ret = find_probe_trace_events_from_map(pev, tevs, max_tevs, target); > > + if (ret > 0) > > + return ret; /* Found in symbol table */ > > + } > > +#endif > > And should be in an arch helper, not a big powerpc wart dropped in the middle > of the generic code. Sure - will change. Thanks for the review! - Naveen
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index 174c22e..adcdbd2 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -2382,6 +2382,14 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev, } } +#if defined(__powerpc64__) && defined(_CALL_ELF) && _CALL_ELF == 2 + if (!perf_probe_event_need_dwarf(pev)) { + ret = find_probe_trace_events_from_map(pev, tevs, max_tevs, target); + if (ret > 0) + return ret; /* Found in symbol table */ + } +#endif + /* Convert perf_probe_event with debuginfo */ ret = try_to_find_probe_trace_events(pev, tevs, max_tevs, target); if (ret != 0)
Use symbol table lookups by default if DWARF is not necessary, since powerpc ABIv2 encodes local entry points in the symbol table and the function entry address in DWARF may not be appropriate for kprobes, as described here: https://sourceware.org/bugzilla/show_bug.cgi?id=17638 Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> --- tools/perf/util/probe-event.c | 8 ++++++++ 1 file changed, 8 insertions(+)