perf powerpc: Fix kprobe and kretprobe handling with kallsyms on ppc64le

[cascardo/linux.git] / tools / perf / arch / powerpc / util / sym-handling.c

diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index bbc1a50..6974ba0 100644 (file)
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -71,12 +71,21 @@ 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.
+        * When probing at a function entry point, we normally always want the
+        * LEP since that catches calls to the function through both the GEP and
+        * the LEP. Hence, we would like to probe at an offset of 8 bytes if
+        * the user only specified the function entry.
+        *
+        * However, if the user specifies an offset, we fall back to using the
+        * GEP since all userspace applications (objdump/readelf) show function
+        * disassembly with offsets from the GEP.
+        *
+        * In addition, we shouldn't specify an offset for kretprobes.
         */
-       if (!pev->uprobes && map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS) {
-               tev->point.address += PPC64LE_LEP_OFFSET;
+       if (pev->point.offset || pev->point.retprobe || !map)
+               return;
+
+       if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS)
                tev->point.offset += PPC64LE_LEP_OFFSET;
-       }
 }
 #endif