Re: [PATCH 2/7] Compiler Attributes: use the no-underscores syntax

From: Nick Desaulniers
Date: Fri Aug 31 2018 - 14:52:07 EST


On Fri, Aug 31, 2018 at 10:05 AM Miguel Ojeda
<miguel.ojeda.sandonis@xxxxxxxxx> wrote:
>
> The attribute syntax optionally allows to surround attribute names
> with "__" in order to avoid collisions with macros of the same name
> (see https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html).
>
> This homogenizes all attributes to use the syntax without underscores.
>
> 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: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Cc: Joe Perches <joe@xxxxxxxxxxx>
> Cc: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>
> ---
> include/linux/compiler-clang.h | 2 +-
> include/linux/compiler-gcc.h | 4 ++--
> include/linux/compiler.h | 4 ++--
> include/linux/compiler_types.h | 8 ++++----
> 4 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index b1ce500fe8b3..efda74f4eeba 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -43,4 +43,4 @@
> #define barrier() __asm__ __volatile__("" : : : "memory")
> #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
> #define __assume_aligned(a, ...) \
> - __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
> + __attribute__((assume_aligned(a, ## __VA_ARGS__)))
> diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
> index 0a2d06677d83..dbfbecf703f8 100644
> --- a/include/linux/compiler-gcc.h
> +++ b/include/linux/compiler-gcc.h
> @@ -132,7 +132,7 @@
> } while (0)
>
> /* Mark a function definition as prohibited from being cloned. */
> -#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
> +#define __noclone __attribute__((noclone, optimize("no-tracer")))
>
> #if defined(RANDSTRUCT_PLUGIN) && !defined(__CHECKER__)
> #define __randomize_layout __attribute__((randomize_layout))
> @@ -165,7 +165,7 @@
> * compiler should see some alignment anyway, when the return value is
> * massaged by 'flags = ptr & 3; ptr &= ~3;').
> */
> -#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
> +#define __assume_aligned(a, ...) __attribute__((assume_aligned(a, ## __VA_ARGS__)))
> #endif
>
> /*
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index 7c0157d50964..e0e55eb3f242 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -23,7 +23,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
> #define __branch_check__(x, expect, is_constant) ({ \
> long ______r; \
> static struct ftrace_likely_data \
> - __attribute__((__aligned__(4))) \
> + __attribute__((aligned(4))) \

Can this be __aligned(4)? As in make use of the newly feature detected
attributes?

> __attribute__((section("_ftrace_annotated_branch"))) \

Sorry to ask for cleanups on code you didn't touch, but since you're
here, can you make this __section("_ftrace_annotated_branch")?

> ______f = { \
> .data.func = __func__, \
> @@ -59,7 +59,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
> ({ \
> int ______r; \
> static struct ftrace_branch_data \
> - __attribute__((__aligned__(4))) \
> + __attribute__((aligned(4))) \
> __attribute__((section("_ftrace_branch"))) \

Ditto.

> ______f = { \
> .func = __func__, \
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index b6534292ea33..7cd958360ead 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -159,7 +159,7 @@ struct ftrace_likely_data {
> sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
>
> #ifndef __attribute_const__
> -#define __attribute_const__ __attribute__((__const__))
> +#define __attribute_const__ __attribute__((const))
> #endif
>
> #ifndef __noclone
> @@ -203,14 +203,14 @@ struct ftrace_likely_data {
> #define __maybe_unused __attribute__((unused))
> #define __always_unused __attribute__((unused))
> #define __mode(x) __attribute__((mode(x)))
> -#define __malloc __attribute__((__malloc__))
> -#define __used __attribute__((__used__))
> +#define __malloc __attribute__((malloc))
> +#define __used __attribute__((used))
> #define __noreturn __attribute__((noreturn))
> #define __packed __attribute__((packed))
> #define __weak __attribute__((weak))
> #define __alias(symbol) __attribute__((alias(#symbol)))
> #define __cold __attribute__((cold))
> -#define __section(S) __attribute__((__section__(#S)))
> +#define __section(S) __attribute__((section(#S)))
>
>
> #ifdef CONFIG_ENABLE_MUST_CHECK
> --
> 2.17.1
>

With the above changes requested (or follow up patch added to the series):
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>

Also,
Series looks great, trying to provide reviews one by one, just very
busy today (and Monday off).

--
Thanks,
~Nick Desaulniers