Marco Elver 80d7476fa2 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>

2021-12-09 16:42:29 -08:00

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