microblaze: ftrace: Add dynamic trace support

With dynamic function tracer, by default, _mcount is defined as an
"empty" function, it returns directly without any more action. When
enabling it in user-space, it will jump to a real tracing
function(ftrace_caller), and do the real job for us.

Differ from the static function tracer, dynamic function tracer provides
two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the
tracing of some indicated kernel functions(set_ftrace_filter).

In the kernel version, there is only one "_mcount" string for every
kernel function, so, we just need to match this one in mcount_regex of
scripts/recordmcount.pl.

For more information please look at code and Documentation/trace folder.

Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 3 insertions, 2 deletions

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index d016c710b3af..5f556b786cd1 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -245,7 +245,6 @@ if ($arch eq "x86_64") {
     $ld .= " -m elf64_sparc";
     $cc .= " -m64";
     $objcopy .= " -O elf64-sparc";
-
 } elsif ($arch eq "mips") {
     # To enable module support, we need to enable the -mlong-calls option
     # of gcc for module, after using this option, we can not get the real
@@ -298,7 +297,9 @@ if ($arch eq "x86_64") {
 		"^([0-9a-fA-F]+)\\s+<(.|[^\$]L.*?|\$[^L].*?|[^\$][^L].*?)>:";
 	    $type = ".dword";
     }
-
+} elsif ($arch eq "microblaze") {
+    # Microblaze calls '_mcount' instead of plain 'mcount'.
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";
 } else {
     die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
 }