From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76B13371064; Mon, 23 Feb 2026 19:11:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771873873; cv=none; b=qoV9UrhZeRX8Koti0jdn/AMOYxYlibeqgGUqryR+X1MIg3CIJw01/c6pBmyvErxAiBbLbIH9wSvMHlK84A7hBetsXu0sKiHvPEA/pHW3pkpuAGoberWuLYYOe62G6tAjvBqiJCoLdaUXSmNISHBuLuVPSwiwH2vkXy1HcH9cbn0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771873873; c=relaxed/simple; bh=HnBXmWSMpA4wuIlOSxrj2rJBVS6hgScD9wUDZt2+qlw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=XcNsgIbSEdX0gFjuklQl5ezkJZLW5XeNa6R029cUzZdmVWu1TCQ6kPZjVbiKROSw8C2aFuZfx5Es/uufjyKOLJU4TTliDP8F4iwpr8zE2Yz0slzt0h5AqElQd7eOOmW8ibnCewbegiO27pUp9CKbyI0g/h1Ycr5WnaoO2alY4Wg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ec7rpLCA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ec7rpLCA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9AEF7C2BCB5; Mon, 23 Feb 2026 19:11:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771873873; bh=HnBXmWSMpA4wuIlOSxrj2rJBVS6hgScD9wUDZt2+qlw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Ec7rpLCAzCv/KZRrk93iS8TKBy0dmX0TGeVU6K4v5xX/A3r84WlF1+spB2Ck3L8+F Ly7Wrk5nDJOONGQAATDn57wpDwS2nId7NK4Vw6pPbxqhuUY3hzAD8tHDKWPeYQ16aq CDGEXsS4binEbD98XFg/kkeskjcNzRQjVBeAbf9hU+krUTPdo4EdS3QsbFUpmWqK+x 83fmxFV+JzQ6K58ijzWKw7NoMdRiJVu6YnkQ+ER5K9bPSOKZ9CiQSYDQwcw9L4xCAq zh+5+/I2WpfYgv6lc5TMsUwpiBXIECDLTQU1MmY+kExyurkj5huthCznFvUTJv9pGV pHQjm+oF6bRiA== From: Nathan Chancellor Date: Mon, 23 Feb 2026 12:10:29 -0700 Subject: [PATCH 2/2] kbuild: Use '-fms-anonymous-structs' if it is available Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260223-fms-anonymous-structs-v1-2-8ee406d3c36c@kernel.org> References: <20260223-fms-anonymous-structs-v1-0-8ee406d3c36c@kernel.org> In-Reply-To: <20260223-fms-anonymous-structs-v1-0-8ee406d3c36c@kernel.org> To: Nathan Chancellor , Nicolas Schier Cc: Linus Torvalds , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Ard Biesheuvel , Ilias Apalodimas , Nick Desaulniers , Bill Wendling , Justin Stitt , Kees Cook , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-efi@vger.kernel.org, llvm@lists.linux.dev X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=2260; i=nathan@kernel.org; h=from:subject:message-id; bh=HnBXmWSMpA4wuIlOSxrj2rJBVS6hgScD9wUDZt2+qlw=; b=owGbwMvMwCUmm602sfCA1DTG02pJDJlzllnaL/tzZJ9j+UqRFKP/HVNX104yzPm+PPiz5Fdep pLXR1Z0d5SyMIhxMciKKbJUP1Y9bmg45yzjjVOTYOawMoEMYeDiFICJlJ1h+Gf2bHvS3EU6Cuzv 6lVV6lZmRpcf6jghx2ystVX28+qCK1GMDBd67Cest0lolmS6u+nMHYW1j73/xRXE1p4vP+5/d3u xCTcA X-Developer-Key: i=nathan@kernel.org; a=openpgp; fpr=2437CB76E544CB6AB3D9DFD399739260CB6CB716 Clang recently added '-fms-anonymous-structs' [1] to specifically enable the Microsoft tagged anonymous structure / union extension, for which the kernel added '-fms-extensions' in commit c4781dc3d1cf ("Kbuild: enable -fms-extensions"). Switch to this more narrow option if it is available, which would have helped avoid the issue addressed by commit a6773e6932cb ("jfs: Rename _inline to avoid conflict with clang's '-fms-extensions'"). GCC has talked about adding a similar flag [2] as well but potentially naming it differently. Move the selection of the flag to Kconfig to make it easier to use cc-option (as CC_FLAGS_DIALECT may be used in arch Makefiles, which may be too early for cc-option in Kbuild) and customize based on compiler flag names. Link: https://github.com/llvm/llvm-project/commit/c391efe6fb67329d8e2fd231692cc6b0ea902956 [1] Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123623 [2] Signed-off-by: Nathan Chancellor --- Makefile | 2 +- init/Kconfig | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 06ff3032a6bc..1d5c0ab9ed5c 100644 --- a/Makefile +++ b/Makefile @@ -791,7 +791,7 @@ endif CC_FLAGS_DIALECT := -std=gnu11 # Allow including a tagged struct or union anonymously in another struct/union. -CC_FLAGS_DIALECT += -fms-extensions +CC_FLAGS_DIALECT += $(CONFIG_CC_MS_EXTENSIONS) # Clang enables warnings about GNU and Microsoft extensions by default, disable # them because this is expected with the above options. ifdef CONFIG_CC_IS_CLANG diff --git a/init/Kconfig b/init/Kconfig index c25869cf59c1..c4282d049463 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -960,6 +960,11 @@ config CC_IMPLICIT_FALLTHROUGH default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) +config CC_MS_EXTENSIONS + string + default "-fms-anonymous-structs" if $(cc-option,-fms-anonymous-structs) + default "-fms-extensions" + # Currently, disable gcc-10+ array-bounds globally. # It's still broken in gcc-13, so no upper bound yet. config GCC10_NO_ARRAY_BOUNDS -- 2.53.0