Commit-ID: c907420fdaec78b17f59a6011cb5f9d6051c6a35
Gitweb: http://git.kernel.org/tip/c907420fdaec78b17f59a6011cb5f9d6051c6a35
Author: Jan Beulich <[email protected]>
AuthorDate: Mon, 19 Sep 2016 07:27:08 -0600
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 20 Sep 2016 08:26:41 +0200
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 <asm/rwsem.h>")
... 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 <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
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 8dbc762..3d33a71 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;
}
