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[23.128.96.18]) by mx.google.com with ESMTP id 17si12031767ejv.562.2021.03.15.11.34.05; Mon, 15 Mar 2021 11:34:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=GOq7kh1O; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237853AbhCOOou (ORCPT + 99 others); Mon, 15 Mar 2021 10:44:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:51130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233560AbhCOOEC (ORCPT ); Mon, 15 Mar 2021 10:04:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 56E7164EF1; Mon, 15 Mar 2021 14:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615817042; bh=tTJVqx+rVDBWCwqr4gWuVNJmGyEQKTlZp9sbHeogfm8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GOq7kh1OaKlGrD6KX8+U8Etl1SVNJ9LmgIjORGjzGgN32P84s1oZbV18hL38b7c98 pzfiU3pKYKVxVRSzfAglwH6cis/5/0vp3ciwl3+X0Qc7zonANjMRkeSHmRb0IEHCq2 LDA6lMwK7F9NshPTc4BU2vU42xaeds2RUDmmGTFk= From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Nathan Chancellor , Kees Cook , Miguel Ojeda , Nick Desaulniers , Luc Van Oostenryck , Masahiro Yamada , Nick Hu , Greentime Hu , Vincent Chen , Paul Walmsley , Palmer Dabbelt , Albert Ou , Guo Ren , Randy Dunlap , Sami Tolvanen , Marco Elver , Arvind Sankar , Andrew Morton , Linus Torvalds Subject: [PATCH 5.11 271/306] linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP* Date: Mon, 15 Mar 2021 14:55:34 +0100 Message-Id: <20210315135516.826234184@linuxfoundation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210315135507.611436477@linuxfoundation.org> References: <20210315135507.611436477@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg Kroah-Hartman From: Arnd Bergmann commit 97e4910232fa1f81e806aa60c25a0450276d99a2 upstream. Separating compiler-clang.h from compiler-gcc.h inadventently dropped the definitions of the three HAVE_BUILTIN_BSWAP macros, which requires falling back to the open-coded version and hoping that the compiler detects it. Since all versions of clang support the __builtin_bswap interfaces, add back the flags and have the headers pick these up automatically. This results in a 4% improvement of compilation speed for arm defconfig. Note: it might also be worth revisiting which architectures set CONFIG_ARCH_USE_BUILTIN_BSWAP for one compiler or the other, today this is set on six architectures (arm32, csky, mips, powerpc, s390, x86), while another ten architectures define custom helpers (alpha, arc, ia64, m68k, mips, nios2, parisc, sh, sparc, xtensa), and the rest (arm64, h8300, hexagon, microblaze, nds32, openrisc, riscv) just get the unoptimized version and rely on the compiler to detect it. A long time ago, the compiler builtins were architecture specific, but nowadays, all compilers that are able to build the kernel have correct implementations of them, though some may not be as optimized as the inline asm versions. The patch that dropped the optimization landed in v4.19, so as discussed it would be fairly safe to backport this revert to stable kernels to the 4.19/5.4/5.10 stable kernels, but there is a remaining risk for regressions, and it has no known side-effects besides compile speed. Link: https://lkml.kernel.org/r/20210226161151.2629097-1-arnd@kernel.org Link: https://lore.kernel.org/lkml/20210225164513.3667778-1-arnd@kernel.org/ Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive") Signed-off-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Reviewed-by: Kees Cook Acked-by: Miguel Ojeda Acked-by: Nick Desaulniers Acked-by: Luc Van Oostenryck Cc: Masahiro Yamada Cc: Nick Hu Cc: Greentime Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Guo Ren Cc: Randy Dunlap Cc: Sami Tolvanen Cc: Marco Elver Cc: Arvind Sankar Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/compiler-clang.h | 6 ++++++ 1 file changed, 6 insertions(+) --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -41,6 +41,12 @@ #define __no_sanitize_thread #endif +#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) +#define __HAVE_BUILTIN_BSWAP32__ +#define __HAVE_BUILTIN_BSWAP64__ +#define __HAVE_BUILTIN_BSWAP16__ +#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ + #if __has_feature(undefined_behavior_sanitizer) /* GCC does not have __SANITIZE_UNDEFINED__ */ #define __no_sanitize_undefined \