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AJvYcCU7PdJHBVYfLwaeBDMNXqhxzLHSXn4i3Auip6JbYY3l23evWPUbW4JVJ0brLLAeiD+xt/sy5t0kvQ==@kvack.org X-Gm-Message-State: AOJu0YwBQLXuoypAZEgPGeWNwtjQTRc4Wf/4hbJSmDiG1YG84jtqU9Dl jp78QKIGRpi1B+xNOcRo52BrlxzfvETGlN6cko3ogRq5FJHh1fQn342232GjYdOFlgX3HLCVTex IwNwpYsn1O7+QT59s4g== X-Received: from wmoo2.prod.google.com ([2002:a05:600d:102:b0:47d:5bef:a379]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:890b:b0:485:6ec7:2df with SMTP id 5b1f17b1804b1-48715fd50abmr80350625e9.8.1774519811752; Thu, 26 Mar 2026 03:10:11 -0700 (PDT) Date: Thu, 26 Mar 2026 10:10:10 +0000 In-Reply-To: Mime-Version: 1.0 References: <20260322192159.88138-1-ojeda@kernel.org> <20260323000327.111235-1-ojeda@kernel.org> Message-ID: Subject: Re: Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO From: Alice Ryhl To: "Russell King (Oracle)" Cc: Miguel Ojeda , a.hindborg@kernel.org, acourbot@nvidia.com, akpm@linux-foundation.org, anton.ivanov@cambridgegreys.com, bjorn3_gh@protonmail.com, boqun.feng@gmail.com, dakr@kernel.org, david@davidgow.net, gary@garyguo.net, johannes@sipsolutions.net, justinstitt@google.com, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-um@lists.infradead.org, llvm@lists.linux.dev, lossin@kernel.org, mark.rutland@arm.com, mmaurer@google.com, morbo@google.com, nathan@kernel.org, nick.desaulniers+lkml@gmail.com, nicolas.schier@linux.dev, nsc@kernel.org, peterz@infradead.org, richard@nod.at, rust-for-linux@vger.kernel.org, tmgross@umich.edu, urezki@gmail.com, will@kernel.org Content-Type: text/plain; charset="utf-8" X-Rspamd-Queue-Id: A934A80018 X-Stat-Signature: mgq3bk7b9sgiote9iphmpmpu4ri4mq3h X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1774519813-654708 X-HE-Meta: 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 5B+qxQhN 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 23, 2026 at 10:03:26AM +0000, Russell King (Oracle) wrote: > On Mon, Mar 23, 2026 at 01:03:27AM +0100, Miguel Ojeda wrote: > > On Sun, 22 Mar 2026 20:21:59 +0100 Miguel Ojeda wrote: > > > > > > 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? > > > > Another one for arm 32-bit: > > > > LD .tmp_vmlinux1 > > ld.lld: error: undefined symbol: __aeabi_read_tp > > >>> referenced by uaccess.rs:349 (rust/kernel/uaccess.rs:349) > > >>> samples/rust/rust_misc_device.o:(::ioctl) in archive vmlinux.a > > >>> referenced by uaccess.rs:543 (rust/kernel/uaccess.rs:543) > > >>> samples/rust/rust_misc_device.o:(::ioctl) in archive vmlinux.a > > >>> referenced by uaccess.rs:543 (rust/kernel/uaccess.rs:543) > > >>> drivers/android/binder/rust_binder_main.o:(rust_binder_main::rust_binder_ioctl) in archive vmlinux.a > > >>> referenced 36 more times > > Why is Rust generating code for userspace thread accessors for kernel > space, where userspace threads are meaningless. This is totally wrong. > The kernel must not reference __aeabi_read_tp(). > > Note: I know nothing about Rust, but I know enough to say the above is > pointing to a fundamental issue in Rust for 32-bit ARM. I noticed that the Makefile currently uses the arm-unknown-linux-gnueabi target. It should probably not be -linux target to avoid this? Probably it should just be armv7a-none-eabi, right? We gate HAVE_RUST on CPU_32v7, so we should not need to consider the other variants. Alice