[PATCH 06/21] perf probe ppc64le: Fixup function entry if using kallsyms lookup

From: Arnaldo Carvalho de Melo
Date: Mon May 04 2015 - 17:39:47 EST


From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx>

On powerpc ABIv2, if no debug-info is found and we use kallsyms, we need
to fixup the function entry to point to the local entry point. Use
offset of 8 since current toolchains always generate 2 instructions (8
bytes).

Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/92253021e77a104b23b615c8c23bf9501dfe60bf.1430217967.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/arch/powerpc/util/sym-handling.c | 15 +++++++++++++++
tools/perf/util/probe-event.c | 5 +++++
tools/perf/util/probe-event.h | 2 ++
3 files changed, 22 insertions(+)

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index a170060..bbc1a50 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -64,4 +64,19 @@ bool arch__prefers_symtab(void)
{
return true;
}
+
+#define PPC64LE_LEP_OFFSET 8
+
+void arch__fix_tev_from_maps(struct perf_probe_event *pev,
+ struct probe_trace_event *tev, struct map *map)
+{
+ /*
+ * ppc64 ABIv2 local entry point is currently always 2 instructions
+ * (8 bytes) after the global entry point.
+ */
+ if (!pev->uprobes && map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS) {
+ tev->point.address += PPC64LE_LEP_OFFSET;
+ tev->point.offset += PPC64LE_LEP_OFFSET;
+ }
+}
#endif
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4dfb412..eb75a5e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2447,6 +2447,10 @@ static int find_probe_functions(struct map *map, char *name)
#define strdup_or_goto(str, label) \
({ char *__p = strdup(str); if (!__p) goto label; __p; })

+void __weak arch__fix_tev_from_maps(struct perf_probe_event *pev __maybe_unused,
+ struct probe_trace_event *tev __maybe_unused,
+ struct map *map __maybe_unused) { }
+
/*
* Find probe function addresses from map.
* Return an error or the number of found probe_trace_event
@@ -2553,6 +2557,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
strdup_or_goto(pev->args[i].type,
nomem_out);
}
+ arch__fix_tev_from_maps(pev, tev, map);
}

out:
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 52bca4b..180f142 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -136,6 +136,8 @@ extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
extern int show_available_funcs(const char *module, struct strfilter *filter,
bool user);
bool arch__prefers_symtab(void);
+void arch__fix_tev_from_maps(struct perf_probe_event *pev,
+ struct probe_trace_event *tev, struct map *map);

/* Maximum index number of event-name postfix */
#define MAX_EVENT_INDEX 1024
--
2.1.0

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