Re: [PATCH v3 1/2] Compiler Attributes: naked can be shared

[Matthias Kaehlcke]

Sorry, this series got messed up. Apparently the branch was still
rebasing when I ran 'git send-email' :/

On Tue, Sep 25, 2018 at 11:53:38AM -0700, Matthias Kaehlcke wrote:
> From: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>
> 
> The naked attribute is supported by at least gcc >= 4.6 (for ARM,
> which is the only current user), gcc >= 8 (for x86), clang >= 3.1
> and icc >= 13. See https://godbolt.org/z/350Dyc
> 
> Therefore, move it out of compiler-gcc.h so that the definition
> is shared by all compilers.
> 
> This also fixes Clang support for ARM32 --- 815f0ddb346c
> ("include/linux/compiler*.h: make compiler-*.h mutually exclusive").
> 
> Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
> Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> Cc: Eli Friedman <efriedma@xxxxxxxxxxxxxx>
> Cc: Christopher Li <sparse@xxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Cc: Joe Perches <joe@xxxxxxxxxxx>
> Cc: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: linux-sparse@xxxxxxxxxxxxxxx
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Tested-by: Stefan Agner <stefan@xxxxxxxx>
> Reviewed-by: Stefan Agner <stefan@xxxxxxxx>
> Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  include/linux/compiler-gcc.h   | 8 --------
>  include/linux/compiler_types.h | 8 ++++++++
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 25d3dd6b2702..4d36b27214fd 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -79,14 +79,6 @@
>  #define __noretpoline __attribute__((indirect_branch("keep")))
>  #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 __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
>  
>  #define __optimize(level)	__attribute__((__optimize__(level)))
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index 3525c179698c..db192becfec4 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -226,6 +226,14 @@ struct ftrace_likely_data {
>  #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)
>  
>  /*