perf probe ppc: Fix symbol fixup issues due to ELF type

If using the symbol table, symbol addresses are not being fixed up
properly, resulting in probes being placed at wrong addresses:

  # perf probe do_fork
  Added new event:
    probe:do_fork        (on do_fork)

  You can now use it in all perf tools, such as:

	  perf record -e probe:do_fork -aR sleep 1

  # cat /sys/kernel/debug/tracing/kprobe_events
  p:probe/do_fork _text+635952
  # printf "%x" 635952
  9b430
  # grep do_fork /boot/System.map
  c0000000000ab430 T .do_fork

Fix by checking for ELF type ET_DYN used by ppc64 kernels.

Signed-off-by: Naveen N. Rao <[email protected]>
Reviewed-by: Srikar Dronamraju <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/41392bb856ef62d929995e0b61967689b7915207.1430217967.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: rnav

tools/perf/arch/powerpc/util/Build

@@ -1,4 +1,5 @@
 libperf-y += header.o
+libperf-y += sym-handling.o
 
 libperf-$(CONFIG_DWARF) += dwarf-regs.o
 libperf-$(CONFIG_DWARF) += skip-callchain-idx.o

tools/perf/arch/powerpc/util/sym-handling.c

@@ -0,0 +1,19 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * Copyright (C) 2015 Naveen N. Rao, IBM Corporation
+ */
+
+#include "debug.h"
+#include "symbol.h"
+
+#ifdef HAVE_LIBELF_SUPPORT
+bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
+{
+	return ehdr.e_type == ET_EXEC ||
+	       ehdr.e_type == ET_REL ||
+	       ehdr.e_type == ET_DYN;
+}
+#endif

tools/perf/util/symbol-elf.c

@@ -630,6 +630,11 @@ void symsrc__destroy(struct symsrc *ss)
 	close(ss->fd);
 }
 
+bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
+{
+	return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
+}
+
 int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 		 enum dso_binary_type type)
 {
@@ -711,8 +716,7 @@ int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
 						     ".gnu.prelink_undo",
 						     NULL) != NULL);
 	} else {
-		ss->adjust_symbols = ehdr.e_type == ET_EXEC ||
-				     ehdr.e_type == ET_REL;
+		ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
 	}
 
 	ss->name   = strdup(name);

tools/perf/util/symbol.h

@@ -303,4 +303,8 @@ int setup_list(struct strlist **list, const char *list_str,
 int setup_intlist(struct intlist **list, const char *list_str,
 		  const char *list_name);
 
+#ifdef HAVE_LIBELF_SUPPORT
+bool elf__needs_adjust_symbols(GElf_Ehdr ehdr);
+#endif
+
 #endif /* __PERF_SYMBOL */