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authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>2017-03-08 13:56:10 +0530
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-03-14 15:17:39 -0300
commit44ca9341f65295c56e904cce4c84f5778f5c8537 (patch)
tree91d1b1fda6b3c26d42771365ea2e48f4177ecece
parent7ab31d94bff96f4f80b38dc5147622b9f3889ac6 (diff)
perf powerpc: Choose local entry point with kretprobes
perf now uses an offset from _text/_stext for kretprobes if the kernel supports it, rather than the actual function name. As such, let's choose the LEP for powerpc ABIv2 so as to ensure the probe gets hit. Do it only if the kernel supports specifying offsets with kretprobes. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/7445b5334673ef5404ac1d12609bad4d73d2b567.1488961018.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/perf/arch/powerpc/util/sym-handling.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 1030a6e504bb..39dbe512b9fc 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c
@@ -10,6 +10,7 @@
#include "symbol.h"
#include "map.h"
#include "probe-event.h"
+#include "probe-file.h"
#ifdef HAVE_LIBELF_SUPPORT
bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
@@ -79,13 +80,18 @@ void arch__fix_tev_from_maps(struct perf_probe_event *pev,
* 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->point.offset || (!pev->uprobes && pev->point.retprobe) ||
- !map || !sym)
+ if (pev->point.offset || !map || !sym)
return;
+ /* For kretprobes, add an offset only if the kernel supports it */
+ if (!pev->uprobes && pev->point.retprobe) {
+#ifdef HAVE_LIBELF_SUPPORT
+ if (!kretprobe_offset_is_supported())
+#endif
+ return;
+ }
+
lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS)