[RFC PATCH 1/4] ftrace: Make recordmcount.c handle __fentry__

From: Steven Rostedt
Date: Tue Aug 07 2012 - 15:41:26 EST


From: Steven Rostedt <srostedt@xxxxxxxxxx>

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.

Cc: John Reiser <jreiser@xxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
scripts/recordmcount.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 54e35c1..9d1421e 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;
--
1.7.10.4


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