From a510c186abfc870e5c74cf953b646c8a2c07bee1 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 16 Apr 2025 10:20:20 -0700 Subject: [PATCH] compiler_types: Identify compiler versions for __builtin_dynamic_object_size Clarify when __builtin_dynamic_object_size() is available. All our supported Clang versions support it. GCC 12 and later support it. Link to documentation for both. Acked-by: Miguel Ojeda Link: https://lore.kernel.org/r/20250416172016.work.154-kees@kernel.org Signed-off-by: Kees Cook --- include/linux/compiler_types.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 501cffddc2f4..20881cc761fa 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -449,6 +449,11 @@ struct ftrace_likely_data { /* * When the size of an allocated object is needed, use the best available * mechanism to find it. (For cases where sizeof() cannot be used.) + * + * Optional: only supported since gcc >= 12 + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html + * clang: https://clang.llvm.org/docs/LanguageExtensions.html#evaluating-object-size */ #if __has_builtin(__builtin_dynamic_object_size) #define __struct_size(p) __builtin_dynamic_object_size(p, 0) -- 2.25.1