perf symbols: Ignore mapping symbols on aarch64

Aarch64 ELF files use mapping symbols with special names $x, $d
to identify regions of Aarch64 code (see Aarch64 ELF ABI - "ARM
IHI 0056B", section "4.5.4 Mapping symbols").

The patch filters out these symbols at load time, similar to
"696b97a perf symbols: Ignore mapping symbols on ARM" changes
done for ARM before V8.

Also added handling of mapping symbols that has format
"$d.<any>" and similar for both cases.

Note we are not making difference between EM_ARM and
EM_AARCH64 mapping symbols instead code handles superset
of both.

Signed-off-by: Victor Kamensky <[e-mail]>
Acked-by: Namhyung Kim <[e-mail]>
Acked-by: Will Deacon <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Anton Blanchard <[e-mail]>
Cc: Avi Kivity <[e-mail]>
Cc: Dave Martin <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: [e-mail]
Cc: Masami Hiramatsu <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Russell King <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/symbol-elf.c

···
 		/* Reject ARM ELF "mapping symbols": these aren't unique and
 		 * don't identify functions, so will confuse the profile
 		 * output: */
-		if (ehdr.e_machine == EM_ARM) {
-			if (!strcmp(elf_name, "$a") ||
-			    !strcmp(elf_name, "$d") ||
-			    !strcmp(elf_name, "$t"))
+		if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
+			if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
+			    && (elf_name[2] == '\0' || elf_name[2] == '.'))
 				continue;
 		}