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| author | Marco Elver <elver@google.com> | 2021-12-04 13:57:03 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-09 16:42:29 -0800 |
| commit | 80d7476fa20a3cc83f76b3b02a7575891d1e7511 (patch) | |
| tree | fd62454a9e1df35a291244593a77263dde15666f | |
| parent | a70d36e6a0bd867ef42dce8ef46eb9b5a1515fb0 (diff) | |
| download | lwn-80d7476fa20a3cc83f76b3b02a7575891d1e7511.tar.gz lwn-80d7476fa20a3cc83f76b3b02a7575891d1e7511.zip | |
kcsan: Turn barrier instrumentation into macros
Some architectures use barriers in 'extern inline' functions, from which
we should not refer to static inline functions.
For example, building Alpha with gcc and W=1 shows:
./include/asm-generic/barrier.h:70:30: warning: 'kcsan_rmb' is static but used in inline function 'pmd_offset' which is not static
70 | #define smp_rmb() do { kcsan_rmb(); __smp_rmb(); } while (0)
| ^~~~~~~~~
./arch/alpha/include/asm/pgtable.h:293:9: note: in expansion of macro 'smp_rmb'
293 | smp_rmb(); /* see above */
| ^~~~~~~
Which seems to warn about 6.7.4#3 of the C standard:
"An inline definition of a function with external linkage shall not
contain a definition of a modifiable object with static or thread
storage duration, and shall not contain a reference to an identifier
with internal linkage."
Fix it by turning barrier instrumentation into macros, which matches
definitions in <asm/barrier.h>.
Perhaps we can revert this change in future, when there are no more
'extern inline' users left.
Link: https://lkml.kernel.org/r/202112041334.X44uWZXf-lkp@intel.com
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| -rw-r--r-- | include/linux/kcsan-checks.h | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/include/linux/kcsan-checks.h b/include/linux/kcsan-checks.h index 9d2c869167f2..92f3843d9ebb 100644 --- a/include/linux/kcsan-checks.h +++ b/include/linux/kcsan-checks.h @@ -241,28 +241,30 @@ static inline void __kcsan_disable_current(void) { } * disabled with the __no_kcsan function attribute. * * Also see definition of __tsan_atomic_signal_fence() in kernel/kcsan/core.c. + * + * These are all macros, like <asm/barrier.h>, since some architectures use them + * in non-static inline functions. */ #define __KCSAN_BARRIER_TO_SIGNAL_FENCE(name) \ - static __always_inline void kcsan_##name(void) \ - { \ + do { \ barrier(); \ __atomic_signal_fence(__KCSAN_BARRIER_TO_SIGNAL_FENCE_##name); \ barrier(); \ - } -__KCSAN_BARRIER_TO_SIGNAL_FENCE(mb) -__KCSAN_BARRIER_TO_SIGNAL_FENCE(wmb) -__KCSAN_BARRIER_TO_SIGNAL_FENCE(rmb) -__KCSAN_BARRIER_TO_SIGNAL_FENCE(release) + } while (0) +#define kcsan_mb() __KCSAN_BARRIER_TO_SIGNAL_FENCE(mb) +#define kcsan_wmb() __KCSAN_BARRIER_TO_SIGNAL_FENCE(wmb) +#define kcsan_rmb() __KCSAN_BARRIER_TO_SIGNAL_FENCE(rmb) +#define kcsan_release() __KCSAN_BARRIER_TO_SIGNAL_FENCE(release) #elif defined(CONFIG_KCSAN_WEAK_MEMORY) && defined(__KCSAN_INSTRUMENT_BARRIERS__) #define kcsan_mb __kcsan_mb #define kcsan_wmb __kcsan_wmb #define kcsan_rmb __kcsan_rmb #define kcsan_release __kcsan_release #else /* CONFIG_KCSAN_WEAK_MEMORY && ... */ -static inline void kcsan_mb(void) { } -static inline void kcsan_wmb(void) { } -static inline void kcsan_rmb(void) { } -static inline void kcsan_release(void) { } +#define kcsan_mb() do { } while (0) +#define kcsan_wmb() do { } while (0) +#define kcsan_rmb() do { } while (0) +#define kcsan_release() do { } while (0) #endif /* CONFIG_KCSAN_WEAK_MEMORY && ... */ /** |