ftrace: Make recordmcount.c handle __fentry__

With gcc 4.6.0 the -mfentry feature places the function profiling
call at the start of the function. When this is used, the call is
to __fentry__ and not mcount.

Change recordmcount.c to record both callers to __fentry__ and
mcount.

Link: http://lkml.kernel.org/r/20120807194058.990674363@goodmis.org

Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: John Reiser <jreiser@bitwagon.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 54e35c1e5948..9d1421e63ff8 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -261,11 +261,13 @@ static unsigned get_mcountsym(Elf_Sym const *const sym0,
                 &sym0[Elf_r_sym(relp)];
         char const *symname = &str0[w(symp->st_name)];
         char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
+        char const *fentry = "__fentry__";
 
         if (symname[0] == '.')
                 ++symname;  /* ppc64 hack */
         if (strcmp(mcount, symname) == 0 ||
-            (altmcount && strcmp(altmcount, symname) == 0))
+            (altmcount && strcmp(altmcount, symname) == 0) ||
+            (strcmp(fentry, symname) == 0))
                 mcountsym = Elf_r_sym(relp);
 
         return mcountsym;