diff options
authorSteven Rostedt <>2009-05-15 04:33:54 +0000
committerBenjamin Herrenschmidt <>2009-05-18 15:19:05 +1000
commitc3cf8667ed7db58c1960958cbb0a9098d513cc60 (patch)
parent021376a3b655364c92c10be544a3319946a792e8 (diff)
powerpc/ftrace: Fix constraint to be early clobber
After upgrading my distcc boxes from gcc 4.2.2 to 4.4.0, the function graph tracer broke. This was discovered on my x86 boxes. The issue is that gcc used the same register for an output as it did for an input in an asm statement. I first thought this was a bug in gcc and reported it. I was notified that gcc was correct and that the output had to be flagged as an "early clobber". I noticed that powerpc had the same issue and this patch fixes it. Signed-off-by: Steven Rostedt <> Signed-off-by: Benjamin Herrenschmidt <>
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 5b078ee391fc..2d182f119d1d 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -594,7 +594,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
PPC_LONG "2b,4b\n"
- : [old] "=r" (old), [faulted] "=r" (faulted)
+ : [old] "=&r" (old), [faulted] "=r" (faulted)
: [parent] "r" (parent), [return_hooker] "r" (return_hooker)
: "memory"