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Mon, 23 Feb 2026 14:39:10 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 X-ThreadId: AcM5pYIp-jco Date: Mon, 23 Feb 2026 20:38:47 +0100 From: "Ard Biesheuvel" To: "Nathan Chancellor" , "Nicolas Schier" Cc: "Linus Torvalds" , "Catalin Marinas" , "Will Deacon" , "Huacai Chen" , "WANG Xuerui" , "James 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" , "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 Message-Id: <9ba5bb34-2356-4c10-a3d3-f122abe1073b@app.fastmail.com> In-Reply-To: <20260223-fms-anonymous-structs-v1-0-8ee406d3c36c@kernel.org> References: <20260223-fms-anonymous-structs-v1-0-8ee406d3c36c@kernel.org> Subject: Re: [PATCH 0/2] kbuild: Switch from '-fms-extensions' to '-fms-anonymous-structs' when available Content-Type: text/plain Content-Transfer-Encoding: 7bit On Mon, 23 Feb 2026, at 20:10, Nathan Chancellor wrote: > Hi all, > > The kernel enabled '-fms-extensions' in commit c4781dc3d1cf ("Kbuild: > enable -fms-extensions") in 6.19 to gain access to a Microsoft > (originally Plan 9) extension around including a tagged structure/union > anonymously in an other structure/union. Since then, Clang 23.0.0 > (current main) has added a flag to enable only that extension, rather > than all Microsoft extensions, '-fms-anonymous-structs' [1]. Using this > narrower compiler option would have avoided the build error fixed by > commit a6773e6932cb ("jfs: Rename _inline to avoid conflict with clang's > '-fms-extensions'"). While these errors are not expected to be common, > using the narrower option when available has no drawbacks because the > kernel only cares about this extension in '-fms-extensions', no others. > While this could result in build errors for folks using > '-fms-anonymous-structs' if a developer uses another extension in > '-fms-extensions' (either intentionally or unintentionally), flagging > these uses for further scrutiny seems worthwhile. > > This series converts the build system to use that flag when it is > available. The first patch consolidates all of the C dialect flags into > a single variable to make future updates to the dialect flags less > painful, as updating the logic in every place that uses their custom > built C flags is getting cumbersome (and C23 is looming). The second > patch makes the actual switch. > > I would like Nicolas to carry this in the Kbuild tree for 7.1, please > provide Acks as necessary. > > [1]: > https://github.com/llvm/llvm-project/commit/c391efe6fb67329d8e2fd231692cc6b0ea902956 > > --- > Nathan Chancellor (2): > kbuild: Consolidate C dialect options > kbuild: Use '-fms-anonymous-structs' if it is available > Acked-by: Ard Biesheuvel