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| author | Nathan Chancellor <natechancellor@gmail.com> | 2021-01-14 10:34:16 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-04 11:37:41 +0100 |
| commit | cc1c1fe79551b4a9ebde1a59287133a5299b7260 (patch) | |
| tree | 2cfefe246ae1c3dd5cba596ef68bf20de654a4ff | |
| parent | f89de444df595a952a8f6887cfbd057a3bf165cd (diff) | |
| download | linux-stable-cc1c1fe79551b4a9ebde1a59287133a5299b7260.tar.gz linux-stable-cc1c1fe79551b4a9ebde1a59287133a5299b7260.tar.bz2 linux-stable-cc1c1fe79551b4a9ebde1a59287133a5299b7260.zip | |
MIPS: Compare __SYNC_loongson3_war against 0
[ Upstream commit 8790ccf8daf1a8c53b6cb8ce0c9a109274bd3fa8 ]
When building with clang when CONFIG_CPU_LOONGSON3_WORKAROUNDS is
enabled:
In file included from lib/errseq.c:4:
In file included from ./include/linux/atomic.h:7:
./arch/mips/include/asm/atomic.h:52:1: warning: converting the result of
'<<' to a boolean always evaluates to true
[-Wtautological-constant-compare]
ATOMIC_OPS(atomic64, s64)
^
./arch/mips/include/asm/atomic.h:40:9: note: expanded from macro
'ATOMIC_OPS'
return cmpxchg(&v->counter, o, n);
^
./arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro
'cmpxchg'
if (!__SYNC_loongson3_war)
^
./arch/mips/include/asm/sync.h:147:34: note: expanded from macro
'__SYNC_loongson3_war'
# define __SYNC_loongson3_war (1 << 31)
^
While it is not wrong that the result of this shift is always true in a
boolean context, it is not a problem here. Regardless, the warning is
really noisy so rather than making the shift a boolean implicitly, use
it in an equality comparison so the shift is used as an integer value.
Fixes: 4d1dbfe6cbec ("MIPS: atomic: Emit Loongson3 sync workarounds within asm")
Fixes: a91f2a1dba44 ("MIPS: cmpxchg: Omit redundant barriers for Loongson3")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/mips/include/asm/atomic.h | 2 | ||||
| -rw-r--r-- | arch/mips/include/asm/cmpxchg.h | 6 |
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h index f904084fcb1f..27ad76791539 100644 --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -248,7 +248,7 @@ static __inline__ int pfx##_sub_if_positive(type i, pfx##_t * v) \ * bltz that can branch to code outside of the LL/SC loop. As \ * such, we don't need to emit another barrier here. \ */ \ - if (!__SYNC_loongson3_war) \ + if (__SYNC_loongson3_war == 0) \ smp_mb__after_atomic(); \ \ return result; \ diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h index 5b0b3a6777ea..ed8f3f3c4304 100644 --- a/arch/mips/include/asm/cmpxchg.h +++ b/arch/mips/include/asm/cmpxchg.h @@ -99,7 +99,7 @@ unsigned long __xchg(volatile void *ptr, unsigned long x, int size) * contains a completion barrier prior to the LL, so we don't \ * need to emit an extra one here. \ */ \ - if (!__SYNC_loongson3_war) \ + if (__SYNC_loongson3_war == 0) \ smp_mb__before_llsc(); \ \ __res = (__typeof__(*(ptr))) \ @@ -191,7 +191,7 @@ unsigned long __cmpxchg(volatile void *ptr, unsigned long old, * contains a completion barrier prior to the LL, so we don't \ * need to emit an extra one here. \ */ \ - if (!__SYNC_loongson3_war) \ + if (__SYNC_loongson3_war == 0) \ smp_mb__before_llsc(); \ \ __res = cmpxchg_local((ptr), (old), (new)); \ @@ -201,7 +201,7 @@ unsigned long __cmpxchg(volatile void *ptr, unsigned long old, * contains a completion barrier after the SC, so we don't \ * need to emit an extra one here. \ */ \ - if (!__SYNC_loongson3_war) \ + if (__SYNC_loongson3_war == 0) \ smp_llsc_mb(); \ \ __res; \ |