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helo=luna.linkmauve.fr; envelope-from=linkmauve@linkmauve.fr; receiver=lists.ozlabs.org) Received: from luna.linkmauve.fr (unknown [IPv6:2a01:e0a:1040:9780:49:5ff:fe41:d261]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4g0TZ53QKSz30Tx for ; Wed, 22 Apr 2026 03:17:33 +1000 (AEST) Received: by luna.linkmauve.fr (Postfix, from userid 1000) id 7F73DF40852; Tue, 21 Apr 2026 19:17:29 +0200 (CEST) Date: Tue, 21 Apr 2026 19:17:29 +0200 From: Link Mauve To: Link Mauve Cc: Gary Guo , Mukesh Kumar Chaurasiya , maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, peterz@infradead.org, jpoimboe@kernel.org, jbaron@akamai.com, aliceryhl@google.com, rostedt@goodmis.org, ardb@kernel.org, ojeda@kernel.org, boqun@kernel.org, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, tmgross@umich.edu, dakr@kernel.org, nathan@kernel.org, nick.desaulniers+lkml@gmail.com, morbo@google.com, justinstitt@google.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH V11 1/4] rust: Fix "multiple candidates for rmeta dependency core" error Message-ID: References: <20260417152253.2312961-1-mkchauras@gmail.com> <20260417152253.2312961-2-mkchauras@gmail.com> 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 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Jabber-ID: linkmauve@linkmauve.fr On Tue, Apr 21, 2026 at 07:10:38PM +0200, Link Mauve wrote: > On Tue, Apr 21, 2026 at 05:51:42PM +0100, Gary Guo wrote: > > On Tue Apr 21, 2026 at 5:36 PM BST, Link Mauve wrote: > > > > > This works fine for the core crate, but now panic_qr also gets the same > > > issue, here it is with V=1: > > > ``` > > > + powerpc-linux-musl-ld -EB -m elf32ppc -z noexecstack --no-warn-rwx-segments -Bstatic --build-id=sha1 --orphan-handling=warn --script=./arch/powerpc/kernel/vmlinux.lds --strip-debug -o .tmp_vmlinux1 --whole-archive vmlinux.a .vmlinux.export.o init/version-timestamp.o --no-whole-archive --start-group --end-group .tmp_vmlinux0.kallsyms.o > > > powerpc-linux-musl-ld: drivers/gpu/drm/drm_panic_qr.o: in function `::next': > > > drm_panic_qr.f39a15fa3c72e9fe-cgu.0:(.text+0x200c): undefined reference to `__udivdi3' > > > ``` > > > > > > From a cursory look at the SegmentIterator::next() function I don’t > > > understand where the division could come up, but it’s actually nice to > > > get an error when operations which shouldn’t happen happen anyway, it > > > makes it more likely to get them fixed. > > > > There is divide / modular by 10 code. Although, this shouldn't really cause > > __udivdi3 to be generated for constant divisor, unless `-C opt-level=s` is used. > > Do you happen to use that opt-level? > > Indeed that was it! > > With CONFIG_CC_OPTIMIZE_FOR_SIZE=y the kernel is 4 MiB large, and with > CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE=y it is 4.9 MiB large, but > CONFIG_DRM_PANIC_SCREEN_QR_CODE=y works. > > As I target the Wii which has only 88 MiB of RAM, a difference of > 920 KiB is actually quite important, and someone[1] is even making it > work on the GameCube and its 24 MiB of RAM where it becomes critical. At runtime it’s even worse, the dtbImage.wii is only 920 KiB bigger, but the kernel code in memory goes from 5660 KiB to 7856 KiB, or 2.2 MiB bigger. > > > > > Best, > > Gary > > > > [1] https://github.com/Wii-Linux/wii-linux-ngx/pull/13#issuecomment-4233447365 > > -- > Link Mauve -- Link Mauve