Prepare for GCC KCFI support and move the __nocfi attribute from
compiler-clang.h to compiler_types.h. This was already gated by
CONFIG_CFI_CLANG, so this remains safe for non-KCFI GCC builds.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Ramon de C Valle <rcvalle@google.com>
Cc: <llvm@lists.linux.dev>
---
 include/linux/compiler-clang.h | 5 -----
 include/linux/compiler_types.h | 4 +++-
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index fa4ffe037bc7..7a4568e421dc 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -96,11 +96,6 @@
 # define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
 #endif
 
-#if __has_feature(kcfi)
-/* Disable CFI checking inside a function. */
-#define __nocfi		__attribute__((__no_sanitize__("kcfi")))
-#endif
-
 /*
  * Turn individual warnings and errors on and off locally, depending
  * on version.
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 16755431fc11..a910f9fa5341 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -432,7 +432,9 @@ struct ftrace_likely_data {
 # define __noscs
 #endif
 
-#ifndef __nocfi
+#if defined(CONFIG_CFI_CLANG)
+# define __nocfi		__attribute__((__no_sanitize__("kcfi")))
+#else
 # define __nocfi
 #endif
 
-- 
2.34.1

On Wed, Sep 03, 2025 at 08:46:40PM -0700, Kees Cook wrote:
> Prepare for GCC KCFI support and move the __nocfi attribute from
> compiler-clang.h to compiler_types.h. This was already gated by
> CONFIG_CFI_CLANG, so this remains safe for non-KCFI GCC builds.
> 
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---

I reviewed this on v1:

https://lore.kernel.org/20250827194657.GA3572128@ax162/

but just to make sure it sticks :)

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
>  include/linux/compiler-clang.h | 5 -----
>  include/linux/compiler_types.h | 4 +++-
>  2 files changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index fa4ffe037bc7..7a4568e421dc 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -96,11 +96,6 @@
>  # define __noscs	__attribute__((__no_sanitize__("shadow-call-stack")))
>  #endif
>  
> -#if __has_feature(kcfi)
> -/* Disable CFI checking inside a function. */
> -#define __nocfi		__attribute__((__no_sanitize__("kcfi")))
> -#endif
> -
>  /*
>   * Turn individual warnings and errors on and off locally, depending
>   * on version.
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index 16755431fc11..a910f9fa5341 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -432,7 +432,9 @@ struct ftrace_likely_data {
>  # define __noscs
>  #endif
>  
> -#ifndef __nocfi
> +#if defined(CONFIG_CFI_CLANG)
> +# define __nocfi		__attribute__((__no_sanitize__("kcfi")))
> +#else
>  # define __nocfi
>  #endif
>  
> -- 
> 2.34.1
>