Commit eb5c2d4b authored by Will Deacon's avatar Will Deacon
Browse files

compiler.h: Move compiletime_assert() macros into compiler_types.h 

The kernel test robot reports that moving READ_ONCE() out into its own
header breaks a W=1 build for parisc, which is relying on the definition
of compiletime_assert() being available:

  | In file included from ./arch/parisc/include/generated/asm/rwonce.h:1,
  |                  from ./include/asm-generic/barrier.h:16,
  |                  from ./arch/parisc/include/asm/barrier.h:29,
  |                  from ./arch/parisc/include/asm/atomic.h:11,
  |                  from ./include/linux/atomic.h:7,
  |                  from kernel/locking/percpu-rwsem.c:2:
  | ./arch/parisc/include/asm/atomic.h: In function 'atomic_read':
  | ./include/asm-generic/rwonce.h:36:2: error: implicit declaration of function 'compiletime_assert' [-Werror=implicit-function-declaration]
  |    36 |  compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
  |       |  ^~~~~~~~~~~~~~~~~~
  | ./include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
  |    49 |  compiletime_assert_rwonce_type(x);    \
  |       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  | ./arch/parisc/include/asm/atomic.h:73:9: note: in expansion of macro 'READ_ONCE'
  |    73 |  return READ_ONCE((v)->counter);
  |       |         ^~~~~~~~~

Move these macros into compiler_types.h, so that they are available to
READ_ONCE() and friends.

Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-July/587094.html


Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent ad83ec6c

include/linux/compiler.h

+0 −41
Original line number Diff line number Diff line
@@ -273,47 +273,6 @@ static inline void *offset_to_ptr(const int *off) 


#endif /* __ASSEMBLY__ */



/* Compile time object size, -1 for unknown */

#ifndef __compiletime_object_size

# define __compiletime_object_size(obj) -1

#endif

#ifndef __compiletime_warning

# define __compiletime_warning(message)

#endif

#ifndef __compiletime_error

# define __compiletime_error(message)

#endif



#ifdef __OPTIMIZE__

# define __compiletime_assert(condition, msg, prefix, suffix)		\

	do {								\

		extern void prefix ## suffix(void) __compiletime_error(msg); \

		if (!(condition))					\

			prefix ## suffix();				\

	} while (0)

#else

# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)

#endif



#define _compiletime_assert(condition, msg, prefix, suffix) \

	__compiletime_assert(condition, msg, prefix, suffix)



/**

 * compiletime_assert - break build and emit msg if condition is false

 * @condition: a compile-time constant condition to check

 * @msg:       a message to emit if condition is false

 *

 * In tradition of POSIX assert, this macro will break the build if the

 * supplied condition is *false*, emitting the supplied error message if the

 * compiler has support to do so.

 */

#define compiletime_assert(condition, msg) \

	_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)



#define compiletime_assert_atomic_type(t)				\

	compiletime_assert(__native_word(t),				\

		"Need native word sized stores/loads for atomicity.")



/* &a[0] degrades to a pointer: a different type from an array */

#define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))

include/linux/compiler_types.h

+41 −0
Original line number Diff line number Diff line
@@ -300,6 +300,47 @@ struct ftrace_likely_data { 
	(sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \

	 sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))



/* Compile time object size, -1 for unknown */

#ifndef __compiletime_object_size

# define __compiletime_object_size(obj) -1

#endif

#ifndef __compiletime_warning

# define __compiletime_warning(message)

#endif

#ifndef __compiletime_error

# define __compiletime_error(message)

#endif



#ifdef __OPTIMIZE__

# define __compiletime_assert(condition, msg, prefix, suffix)		\

	do {								\

		extern void prefix ## suffix(void) __compiletime_error(msg); \

		if (!(condition))					\

			prefix ## suffix();				\

	} while (0)

#else

# define __compiletime_assert(condition, msg, prefix, suffix) do { } while (0)

#endif



#define _compiletime_assert(condition, msg, prefix, suffix) \

	__compiletime_assert(condition, msg, prefix, suffix)



/**

 * compiletime_assert - break build and emit msg if condition is false

 * @condition: a compile-time constant condition to check

 * @msg:       a message to emit if condition is false

 *

 * In tradition of POSIX assert, this macro will break the build if the

 * supplied condition is *false*, emitting the supplied error message if the

 * compiler has support to do so.

 */

#define compiletime_assert(condition, msg) \

	_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)



#define compiletime_assert_atomic_type(t)				\

	compiletime_assert(__native_word(t),				\

		"Need native word sized stores/loads for atomicity.")



/* Helpers for emitting diagnostics in pragmas. */

#ifndef __diag

#define __diag(string)

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