From c907420fdaec78b17f59a6011cb5f9d6051c6a35 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Mon, 19 Sep 2016 07:27:08 -0600 Subject: [PATCH] locking/rwsem, x86: Drop a bogus cc clobber With the addition of uses of GCC's condition code outputs in commit: 35ccfb7114 ("x86, asm: Use CC_SET()/CC_OUT() in ") ... there's now an overlap of outputs and clobbers in __down_write_trylock(). Such overlaps are generally getting tagged with an error (occasionally even with an ICE). I can't really tell why plain GCC 6.2 doesn't detect this (judging by the code it is meant to), while the slightly modified one I use does. Since condition code clobbers are never necessary on x86 (other than perhaps for documentation purposes, which doesn't really get done consistently), remove it altogether rather than inventing something like CC_CLOBBER (to accompany CC_SET/CC_OUT). Signed-off-by: Jan Beulich Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/57E003CC0200007800110102@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/rwsem.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index 8dbc762ad132..3d33a719f5c1 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -154,7 +154,7 @@ static inline bool __down_write_trylock(struct rw_semaphore *sem) : "+m" (sem->count), "=&a" (tmp0), "=&r" (tmp1), CC_OUT(e) (result) : "er" (RWSEM_ACTIVE_WRITE_BIAS) - : "memory", "cc"); + : "memory"); return result; } -- 2.20.1