Perf uretprobe probes on GEP(Glabal Entry Point) which fails to record
all function calls via LEP(Local Entry Point). Fix that by probing on LEP.
Objdump:
00000000100005f0 <doit>:
100005f0: 02 10 40 3c lis r2,4098
100005f4: 00 7f 42 38 addi r2,r2,32512
100005f8: a6 02 08 7c mflr r0
100005fc: 10 00 01 f8 std r0,16(r1)
10000600: f8 ff e1 fb std r31,-8(r1)
Before applying patch:
$ cat /sys/kernel/debug/tracing/uprobe_events
r:probe_uprobe_test/doit /home/ravi/uprobe_test:0x00000000000005f0
After applying patch:
$ cat /sys/kernel/debug/tracing/uprobe_events
r:probe_uprobe_test/doit /home/ravi/uprobe_test:0x00000000000005f8
This is not the case with kretprobe because kernel itself finds LEP
and probes on it.
Signed-off-by: Ravi Bangoria <[email protected]>
---
tools/perf/arch/powerpc/util/sym-handling.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/perf/arch/powerpc/util/sym-handling.c
b/tools/perf/arch/powerpc/util/sym-handling.c
index ed9d5d1..1030a6e 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -82,7 +82,8 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
*
* In addition, we shouldn't specify an offset for kretprobes.
*/
- if (pev->point.offset || pev->point.retprobe || !map || !sym)
+ if (pev->point.offset || (!pev->uprobes && pev->point.retprobe) ||
+ !map || !sym)
return;
lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
--
2.7.4
