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b=S8zGn/i+Spyx9XA47CpCu/vQAg2jkahFRQzQumLqtrDpCNSJTCj03aAkEznFHIBqF BHqQtK9yH0jlsDRFhpqINdr/8qKOFZZ33DoLjiHS1rBQN8A7rN6+cd4XspEv86q4aw fX5sdIVSmixq08mIaV+WQ20CFRO/xOqtaVcHBACJLjdgVgNEAW/1eD2ppZ4E8Sqo34 KMBXF5A5vLLXjt9vVzfBdhnIBFejLTjFksFyWA19+Dk1JNuNC3tUVbCRh3Eo+Ed2YP iTNr+GVTtwyhLeEY70H14v74c5VO6yI6pMXy8ExXxlKbsKAbxCmXLa/pnbG4dlN+CH y4s8jAUhtp60A== Date: Wed, 25 Mar 2026 19:42:26 -0700 From: Nathan Chancellor To: Miguel Ojeda Cc: Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , David Gow , Russell King , Richard Weinberger , Anton Ivanov , Johannes Berg , aliceryhl@google.com, linux-um@lists.infradead.org, llvm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, a.hindborg@kernel.org, acourbot@nvidia.com, akpm@linux-foundation.org, bjorn3_gh@protonmail.com, boqun.feng@gmail.com, dakr@kernel.org, gary@garyguo.net, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lossin@kernel.org, mark.rutland@arm.com, mmaurer@google.com, nicolas.schier@linux.dev, peterz@infradead.org, rust-for-linux@vger.kernel.org, tmgross@umich.edu, urezki@gmail.com, will@kernel.org Subject: Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO Message-ID: <20260326024226.GB2302780@ax162> References: <20260203-inline-helpers-v2-0-beb8547a03c9@google.com> <20260322192159.88138-1-ojeda@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260322192159.88138-1-ojeda@kernel.org> X-Rspamd-Queue-Id: F2992180004 X-Stat-Signature: gghzeqq8kdyq9edwusre1axinufohu8z X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1774492955-394561 X-HE-Meta: U2FsdGVkX1/iCHp+f2g6/HbOVq4HLm3a2b1TH5kl274Tr6Im+1trevXpIAFr9hr68J4frrc3TPYpQCrGusX8mmebdiirgIyHKp0vFkcU2diebE1bRg9gvj3Qr+2RPh5vZpJ4/p9+NiX0abqMdXadHaeBiFKk+CnPgFupJaUzz5mHOfQfV4CyXOUBLC3K5jallcz1vPXxVOK1KQY2Ht2lgrbzZHpRvoyV4xgTi2ep8aXCZz4jyB7q1upOn6SklPhm4TZaOna9PF4O9E5UHFxfMd7ZUooysNwHDYE81BLQZIdR4L/iPB+5t6t4AlfbLpgGy16bwHolges9shumBG6R/Gpt82CoLYsZXa3LbJZ7WUywjPlElD7ttbelqYOA5s8+PZfRjHo9mFqyKV/mSr8VQVxC4zBBH3Cg6DzjYelNiEekUCN/6KbFKass4V8CDH4ubLGlEjjHKedfZ7MjwhhvyITdwY0rp2CAOCEJPujB2tT8BljY+hiNCFgPYFudGoWQOl9QkfZDrgWFqckBZbaUSxfS9TDSB80EMsPW49LokcmdkiBy0t0cPBAlAkKhoYYpcTnftxONeu2gf44yfcu09bdFKbZKY+5NzMbHGnZsss3Sx0AIQJ1uiUkd7g7soNhj62Omy8QXSDYTtfbZhpB6h+VU09GdMjYfCXMoH99ByD0Vk70hiMfN6IH/9MJT4IHsgPClqxN+9EnMsDC1U9Nd/PZWQ6b56vONBdBFlHcYkmr94BuY2ybo7xJQ5/XVWbkNRI0l6H9tryraXxE1zT3EHY5mmUY2jwMsebIJBm3Cit+Fn9BWwVz87pt6HmnEfGTBH/2w7yqjIPQUYIxPwmShlKmdsBDwaWNIhbxmaZXajAI+WT4KhR6f+ZueNfecgMXKi37gp/s1+HHyydLhjbvJlAjwm4mC4z5ZLk4k7XUaLSFKfFl2vlPiPAxsUxk4WQS27QruHUYjrRRansCR8L7 OLjGnX1d WiAnIgwCGhVwd53lBpqW+w1KUTbfQRJU7CgPRHVvcIfPY9tUI6oIZAse9k54hvjYq5mJlnpk+/zvMw4ex8LQAWLQNf1B/ZPP5KVX6bMGFOHQscbwGfz+xJ7jiDYI2DXvr0ADBkIT4iatwR1H25gh7cd6bmFYBWuypvDDOkQiy55g8zZuZewCf3H8anHTPbZ05p0Ezj8lS71PKpIUHwK0lze8k3Yi9BpPUt5+HSS6BHs5deFHD7ULvv8OVrgPnVd2xoQ4yawDSMulTGNFSBhjXJSIB6B3vAC5/3S7560R/w+bh8PflUwRME0sccBdACWJPjA1w5Xzt9A1VXcJXocXk8TK3Ewl3MqOXpJAClwmdBapYXN44tE9yy8YUvg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Mar 22, 2026 at 08:21:59PM +0100, Miguel Ojeda wrote: > - Clang passes `-Werror=unused-command-line-argument`, which means > under arm (i.e. 32-bit) we get: > > clang: error: argument unused during compilation: '-U arm' [-Werror,-Wunused-command-line-argument] > > And under UML I see: > > clang: error: argument unused during compilation: '-I ./arch/um/include/shared' [-Werror,-Wunused-command-line-argument] > clang: error: argument unused during compilation: '-I ./arch/x86/um/shared' [-Werror,-Wunused-command-line-argument] > clang: error: argument unused during compilation: '-I ./arch/um/include/shared/skas' [-Werror,-Wunused-command-line-argument] > > So we would need e.g. `-Wno-unused-command-line-argument` there > close to the `-Wno-override-module` one, unless Kbuild or > ClangBuiltLinux thinks it is important to keep it for this case. No, I don't think it is worth trying to make -Wunused-command-line-argument work for this command. Just disable it. This mirrors what is being done for cmd_cc_o_bc in the distributed ThinLTO: https://lore.kernel.org/20260316212930.120438-3-xur@google.com/ > On the other hand, regardless of whether we fix this (and another > issue in a separate email found thanks to the UML build), we could > instead add `depends on` listing explicitly the architectures where > this is going to be actually tested. That way maintainers can decide > whether they want to support it when they are ready. Thoughts? > > Cc'ing Nathan, Nicolas, Nick, Bill, Justin, David, UML, ARM. I do agree with some of the concerns that adding an architecure dimension to this is a little complicated. I would rather try to flush out those build problems with patches and keep it enabled for all architectures. At the same time though, I understand that enabling it for the "tier 1" architectures is a low barrier of entry for getting the feature upstream, validated, and distributed to the majority of people that would actually use and depend on it, so I ultimately leave that call up to you. > - If we use the `.bc` extension, we need to add a `.gitignore` for > `.bc` files, and an exception for `kernel/time/timeconst.bc`. > > I guess we will not have too many `bc` scripts in the future for > that to be a problem. On the other hand, we have the chance to use > another extension (either for LLVM bitcode or for `bc` scripts). > > But please let me know on e.g. the Kbuild side if someone has > concerns... No real concern on that front but .gitignore has a command to run when modifying it, which will require a !timeconst.bc in a kernel/time/.gitignore file. Cheers, Nathan