Based on the following patch (backported to 2.6.34), with the relevant bits of 3f3f8d2f48acfd8ed3b8e6b7377935da57b27b16 (compiler-gcc.h: Add gcc-recommended GCC_VERSION macro) included so that the patch will build and work. Also include some macros which only appeared in compiler-gcc4.h up until 2.6.39 but were removed later on as these will be required to build this version correctly. From a4a4f1cd733fe5b345db4e8cc19bb8868d562a8a Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Thu, 25 Jun 2015 15:01:02 -0700 Subject: compiler-gcc: integrate the various compiler-gcc[345].h files MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit cb984d101b30eb7478d32df56a0023e4603cba7f upstream. As gcc major version numbers are going to advance rather rapidly in the future, there's no real value in separate files for each compiler version. Deduplicate some of the macros #defined in each file too. Neaten comments using normal kernel commenting style. Signed-off-by: Joe Perches Cc: Andi Kleen Cc: Michal Marek Cc: Segher Boessenkool Cc: Sasha Levin Cc: Anton Blanchard Cc: Alan Modra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [ philm: backport to 3.10-stable ] Signed-off-by: Philip Müller Signed-off-by: Willy Tarreau --- include/linux/compiler-gcc.h | 114 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 110 insertions(+), 4 deletions(-) (limited to 'include/linux/compiler-gcc.h') --- linux-2.6.34/include/linux/compiler-gcc.h.orig 2017-10-12 14:45:06.227956122 -0400 +++ linux-2.6.34/include/linux/compiler-gcc.h 2017-10-12 14:59:26.868001124 -0400 @@ -81,7 +81,125 @@ #define __maybe_unused __attribute__((unused)) #define __always_unused __attribute__((unused)) -#define __gcc_header(x) #x -#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h) -#define gcc_header(x) _gcc_header(x) -#include gcc_header(__GNUC__) +# define GCC_VERSION (__GNUC__ * 10000 \ + + __GNUC_MINOR__ * 100 \ + + __GNUC_PATCHLEVEL__) + +/* gcc version specific checks */ + +#if GCC_VERSION < 30200 +# error Sorry, your compiler is too old - please upgrade it. +#endif + +#if GCC_VERSION < 30300 +# define __used __attribute__((__unused__)) +#else +# define __used __attribute__((__used__)) +#endif + +#ifdef CONFIG_GCOV_KERNEL +# if GCC_VERSION < 30400 +# error "GCOV profiling support for gcc versions below 3.4 not included" +# endif /* __GNUC_MINOR__ */ +#endif /* CONFIG_GCOV_KERNEL */ + +#if GCC_VERSION >= 30400 +#define __must_check __attribute__((warn_unused_result)) +#endif + +#if GCC_VERSION >= 40000 + +/* GCC 4.1.[01] miscompiles __weak */ +#ifdef __KERNEL__ +# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 +# error Your version of gcc miscompiles the __weak directive +# endif +#endif + +#define __used __attribute__((__used__)) +#define __compiler_offsetof(a, b) \ + __builtin_offsetof(a, b) + +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 +# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) +#endif + +#if GCC_VERSION >= 40300 +/* Mark functions as cold. gcc will assume any path leading to a call + * to them will be unlikely. This means a lot of manual unlikely()s + * are unnecessary now for any paths leading to the usual suspects + * like BUG(), printk(), panic() etc. [but let's keep them for now for + * older compilers] + * + * Early snapshots of gcc 4.3 don't support this and we can't detect this + * in the preprocessor, but we can live with this because they're unreleased. + * Maketime probing would be overkill here. + * + * gcc also has a __attribute__((__hot__)) to move hot functions into + * a special section, but I don't see any sense in this right now in + * the kernel context + */ +#define __cold __attribute__((__cold__)) + +#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) + +#ifndef __CHECKER__ +# define __compiletime_warning(message) __attribute__((warning(message))) +# define __compiletime_error(message) __attribute__((error(message))) +#endif /* __CHECKER__ */ +#endif /* GCC_VERSION >= 40300 */ + +#if GCC_VERSION >= 40500 +/* + * Mark a position in code as unreachable. This can be used to + * suppress control flow warnings after asm blocks that transfer + * control elsewhere. + * + * Early snapshots of gcc 4.5 don't support this and we can't detect + * this in the preprocessor, but we can live with this because they're + * unreleased. Really, we need to have autoconf for the kernel. + */ +#define unreachable() __builtin_unreachable() + +/* Mark a function definition as prohibited from being cloned. */ +#define __noclone __attribute__((__noclone__)) + +#endif /* GCC_VERSION >= 40500 */ + +#if GCC_VERSION >= 40600 +/* + * Tell the optimizer that something else uses this function or variable. + */ +#define __visible __attribute__((externally_visible)) +#endif + +/* + * GCC 'asm goto' miscompiles certain code sequences: + * + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 + * + * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. + * + * (asm goto is automatically volatile - the naming reflects this.) + */ +#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) + +#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP +#if GCC_VERSION >= 40400 +#define __HAVE_BUILTIN_BSWAP32__ +#define __HAVE_BUILTIN_BSWAP64__ +#endif +#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600) +#define __HAVE_BUILTIN_BSWAP16__ +#endif +#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ + +#endif /* gcc version >= 40000 specific checks */ + +/* + * A trick to suppress uninitialized variable warning without generating any + * code + */ +#define uninitialized_var(x) x = x + +#define __always_inline inline __attribute__((always_inline))