Perf uretprobe probes on GEP(Global 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 kretprobes because the kernel itself finds LEP
and probes on it.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1475576865-6562-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
a1d9972e59