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>

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 54e35c1e5948c521f9fdebf57c27072b6d844f34..9d1421e63ff82939b249382b17ab886ce4c4ccc9 100644 (file)
--- 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;