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authorJan Beulich <JBeulich@suse.com>2016-09-19 13:27:08 (GMT)
committerIngo Molnar <mingo@kernel.org>2016-09-20 06:26:41 (GMT)
commitc907420fdaec78b17f59a6011cb5f9d6051c6a35 (patch)
tree5b500737af27d491d35f405645231500123bfa84
parente8b61b3f2c5d3ee7804766621c91f38737d38105 (diff)
downloadlinux-c907420fdaec78b17f59a6011cb5f9d6051c6a35.tar.xz
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 <jbeulich@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/57E003CC0200007800110102@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/include/asm/rwsem.h2
1 files changed, 1 insertions, 1 deletions
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;
}