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Commit 71391bdd authored by Xiaozhou Liu's avatar Xiaozhou Liu Committed by Miguel Ojeda
Browse files

include/linux/compiler_types.h: don't pollute userspace with macro definitions 



Macros 'inline' and '__gnu_inline' used to be defined in compiler-gcc.h,
which was (and is) included entirely in (__KERNEL__ && !__ASSEMBLY__).
Commit 815f0ddb ("include/linux/compiler*.h: make compiler-*.h mutually
exclusive") had those macros exposed to userspace, unintentionally.

Then commit a3f8a30f ("Compiler Attributes: use feature checks
instead of version checks") moved '__gnu_inline' back into
(__KERNEL__ && !__ASSEMBLY__) and 'inline' was left behind. Since 'inline'
depends on '__gnu_inline', compiling error showing "unknown type name
‘__gnu_inline’" will pop up, if userspace somehow includes
<linux/compiler.h>.

Other macros like __must_check, notrace, etc. are in a similar situation.
So just move all these macros back into (__KERNEL__ && !__ASSEMBLY__).

Note:
  1. This patch only affects what userspace sees.
  2. __must_check (when !CONFIG_ENABLE_MUST_CHECK) and noinline_for_stack
     were once defined in __KERNEL__ only, but we believe that they can
     be put into !__ASSEMBLY__ too.

Acked-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarXiaozhou Liu <liuxiaozhou@bytedance.com>
Signed-off-by: default avatarMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
parent 40e020c1

include/linux/compiler_types.h

+54 −54
Original line number Original line Diff line number Diff line
@@ -104,6 +104,60 @@ struct ftrace_likely_data { 
	unsigned long			constant;

	unsigned long			constant;

};

};





#ifdef CONFIG_ENABLE_MUST_CHECK

#define __must_check		__attribute__((__warn_unused_result__))

#else

#define __must_check

#endif



#if defined(CC_USING_HOTPATCH)

#define notrace			__attribute__((hotpatch(0, 0)))

#else

#define notrace			__attribute__((__no_instrument_function__))

#endif



/*

 * it doesn't make sense on ARM (currently the only user of __naked)

 * to trace naked functions because then mcount is called without

 * stack and frame pointer being set up and there is no chance to

 * restore the lr register to the value before mcount was called.

 */

#define __naked			__attribute__((__naked__)) notrace



#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)



/*

 * Force always-inline if the user requests it so via the .config.

 * GCC does not warn about unused static inline functions for

 * -Wunused-function.  This turns out to avoid the need for complex #ifdef

 * directives.  Suppress the warning in clang as well by using "unused"

 * function attribute, which is redundant but not harmful for gcc.

 * Prefer gnu_inline, so that extern inline functions do not emit an

 * externally visible function. This makes extern inline behave as per gnu89

 * semantics rather than c99. This prevents multiple symbol definition errors

 * of extern inline functions at link time.

 * A lot of inline functions can cause havoc with function tracing.

 * Do not use __always_inline here, since currently it expands to inline again

 * (which would break users of __always_inline).

 */

#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \

	!defined(CONFIG_OPTIMIZE_INLINING)

#define inline inline __attribute__((__always_inline__)) __gnu_inline \

	__maybe_unused notrace

#else

#define inline inline                                    __gnu_inline \

	__maybe_unused notrace

#endif



#define __inline__ inline

#define __inline   inline



/*

 * Rather then using noinline to prevent stack consumption, use

 * noinline_for_stack instead.  For documentation reasons.

 */

#define noinline_for_stack noinline



#endif /* __KERNEL__ */

#endif /* __KERNEL__ */





#endif /* __ASSEMBLY__ */

#endif /* __ASSEMBLY__ */
@@ -161,58 +215,4 @@ struct ftrace_likely_data { 
#define __diag_error(compiler, version, option, comment) \

#define __diag_error(compiler, version, option, comment) \

	__diag_ ## compiler(version, error, option)

	__diag_ ## compiler(version, error, option)





#ifdef CONFIG_ENABLE_MUST_CHECK

#define __must_check		__attribute__((__warn_unused_result__))

#else

#define __must_check

#endif



#if defined(CC_USING_HOTPATCH)

#define notrace			__attribute__((hotpatch(0, 0)))

#else

#define notrace			__attribute__((__no_instrument_function__))

#endif



/*

 * it doesn't make sense on ARM (currently the only user of __naked)

 * to trace naked functions because then mcount is called without

 * stack and frame pointer being set up and there is no chance to

 * restore the lr register to the value before mcount was called.

 */

#define __naked			__attribute__((__naked__)) notrace



#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)



/*

 * Force always-inline if the user requests it so via the .config.

 * GCC does not warn about unused static inline functions for

 * -Wunused-function.  This turns out to avoid the need for complex #ifdef

 * directives.  Suppress the warning in clang as well by using "unused"

 * function attribute, which is redundant but not harmful for gcc.

 * Prefer gnu_inline, so that extern inline functions do not emit an

 * externally visible function. This makes extern inline behave as per gnu89

 * semantics rather than c99. This prevents multiple symbol definition errors

 * of extern inline functions at link time.

 * A lot of inline functions can cause havoc with function tracing.

 * Do not use __always_inline here, since currently it expands to inline again

 * (which would break users of __always_inline).

 */

#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \

	!defined(CONFIG_OPTIMIZE_INLINING)

#define inline inline __attribute__((__always_inline__)) __gnu_inline \

	__maybe_unused notrace

#else

#define inline inline                                    __gnu_inline \

	__maybe_unused notrace

#endif



#define __inline__ inline

#define __inline   inline



/*

 * Rather then using noinline to prevent stack consumption, use

 * noinline_for_stack instead.  For documentation reasons.

 */

#define noinline_for_stack noinline



#endif /* __LINUX_COMPILER_TYPES_H */
 
#endif /* __LINUX_COMPILER_TYPES_H */