From: Nick Desaulniers ndesaulniers@google.com

commit b83a908498d68fafca931e1276e145b339cac5fb upstream.

Clang 14 will add support for __attribute__((__error__(""))) and __attribute__((__warning__(""))). To make use of these in __compiletime_error and __compiletime_warning (as used by BUILD_BUG and friends) for newer clang and detect/fallback for older versions of clang, move these to compiler_attributes.h and guard them with __has_attribute preprocessor guards.

Link: https://reviews.llvm.org/D106030 Link: https://bugs.llvm.org/show_bug.cgi?id=16428 Link: https://github.com/ClangBuiltLinux/linux/issues/1173 Signed-off-by: Nick Desaulniers ndesaulniers@google.com Reviewed-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Kees Cook keescook@chromium.org [Reworded, landed in Clang 14] Signed-off-by: Miguel Ojeda ojeda@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Bart Van Assche bvanassche@acm.org --- include/linux/compiler-gcc.h | 3 --- include/linux/compiler_attributes.h | 24 ++++++++++++++++++++++++ include/linux/compiler_types.h | 6 ------ 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 4cf524ccab43..ae2de4e1cd6f 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -54,9 +54,6 @@

#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)

-#define __compiletime_warning(message) __attribute__((__warning__(message))) -#define __compiletime_error(message) __attribute__((__error__(message))) - #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) #define __latent_entropy __attribute__((latent_entropy)) #endif diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h index b2a3f4f641a7..08eb06301791 100644 --- a/include/linux/compiler_attributes.h +++ b/include/linux/compiler_attributes.h @@ -30,6 +30,7 @@ # define __GCC4_has_attribute___assume_aligned__ (__GNUC_MINOR__ >= 9) # define __GCC4_has_attribute___copy__ 0 # define __GCC4_has_attribute___designated_init__ 0 +# define __GCC4_has_attribute___error__ 1 # define __GCC4_has_attribute___externally_visible__ 1 # define __GCC4_has_attribute___no_caller_saved_registers__ 0 # define __GCC4_has_attribute___noclone__ 1 @@ -37,6 +38,7 @@ # define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8) # define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9) # define __GCC4_has_attribute___fallthrough__ 0 +# define __GCC4_has_attribute___warning__ 1 #endif

/* @@ -136,6 +138,17 @@ # define __designated_init #endif

+/* + * Optional: only supported since clang >= 14.0 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-err... + */ +#if __has_attribute(__error__) +# define __compiletime_error(msg) __attribute__((__error__(msg))) +#else +# define __compiletime_error(msg) +#endif + /* * Optional: not supported by clang * @@ -272,6 +285,17 @@ */ #define __used __attribute__((__used__))

+/* + * Optional: only supported since clang >= 14.0 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-war... + */ +#if __has_attribute(__warning__) +# define __compiletime_warning(msg) __attribute__((__warning__(msg))) +#else +# define __compiletime_warning(msg) +#endif + /* * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-wea... * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-wea... diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 2a1c202baa1f..eb2bda017ccb 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -281,12 +281,6 @@ struct ftrace_likely_data { #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) \