perf probe: Support probing on offline cross-arch binary

Support probing on offline cross-architecture binary by adding getting
the target machine arch from ELF and choose correct register string for
the machine.

Here is an example:
  -----
  $ perf probe --vmlinux=./vmlinux-arm --definition 'do_sys_open $params'
  p:probe/do_sys_open do_sys_open+0 dfd=%r5:s32 filename=%r1:u32 flags=%r6:s32 mode=%r3:u16
  -----

Here, we can get probe/do_sys_open from above and append it to to the target
machine's tracing/kprobe_events file in the tracefs mountput, usually
/sys/kernel/debug/tracing/kprobe_events (or /sys/kernel/tracing/kprobe_events).

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/147214229717.23638.6440579792548044658.stgit@devbox
[ Add definition for EM_AARCH64 to fix the build on at least centos 6, debian 7 & ubuntu 12.04.5 ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/powerpc/include/dwarf-regs-table.h

@@ -0,0 +1,27 @@
+#ifdef DEFINE_DWARF_REGSTR_TABLE
+/* This is included in perf/util/dwarf-regs.c */
+
+/*
+ * Reference:
+ * http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi-1.9.html
+ * http://refspecs.linux-foundation.org/elf/elfspec_ppc.pdf
+ */
+#define REG_DWARFNUM_NAME(reg, idx)	[idx] = "%" #reg
+
+static const char * const powerpc_regstr_tbl[] = {
+	"%gpr0", "%gpr1", "%gpr2", "%gpr3", "%gpr4",
+	"%gpr5", "%gpr6", "%gpr7", "%gpr8", "%gpr9",
+	"%gpr10", "%gpr11", "%gpr12", "%gpr13", "%gpr14",
+	"%gpr15", "%gpr16", "%gpr17", "%gpr18", "%gpr19",
+	"%gpr20", "%gpr21", "%gpr22", "%gpr23", "%gpr24",
+	"%gpr25", "%gpr26", "%gpr27", "%gpr28", "%gpr29",
+	"%gpr30", "%gpr31",
+	REG_DWARFNUM_NAME(msr,   66),
+	REG_DWARFNUM_NAME(ctr,   109),
+	REG_DWARFNUM_NAME(link,  108),
+	REG_DWARFNUM_NAME(xer,   101),
+	REG_DWARFNUM_NAME(dar,   119),
+	REG_DWARFNUM_NAME(dsisr, 118),
+};
+
+#endif