[PATCH V11 1/4] rust: Fix "multiple candidates for rmeta dependency core" error

[Gary Guo]

On Tue Apr 21, 2026 at 6:47 PM BST, Mukesh Kumar Chaurasiya wrote:
> On Tue, Apr 21, 2026 at 04:57:49PM +0100, Gary Guo wrote:
>> On Tue Apr 21, 2026 at 4:53 PM BST, Mukesh Kumar Chaurasiya wrote:
>> > On Tue, Apr 21, 2026 at 02:26:19PM +0200, Link Mauve wrote:
>> >> On Tue, Apr 21, 2026 at 05:49:32PM +0530, Mukesh Kumar Chaurasiya wrote:
>> >> > On Tue, Apr 21, 2026 at 12:26:51PM +0200, Link Mauve wrote:
>> >> > > On Tue, Apr 21, 2026 at 03:25:22PM +0530, Mukesh Kumar Chaurasiya wrote:
>> >> > > > On Tue, Apr 21, 2026 at 11:38:08AM +0200, Link Mauve wrote:
>> >> > > > > Hi Mukesh,
>> >> > > > > 
>> >> > > > > This patch doesn’t apply on top of mainline, which tree did you base it
>> >> > > > > off?
>> >> > > > > 
>> >> > > > It was on mainline v7.0 tag.
>> >> > > 
>> >> > > Great thanks, they do apply there!
>> >> > > 
>> >> > > I needed three more patches for the kernel to build on PPC32, I’ve
>> >> > > attached them but they are absolutely not patches which could go into
>> >> > > the kernel (except for the second, enabling asm_experimental_arch).
>> >> > > 
>> >> > > What do you think we should do about them?
>> >> > > 
>> >> > Regarding the 2nd patch you sent, As the support is experimental as of
>> >> > now, Let's wait till we get everything stablized, till then we'll use
>> >> > nightly build for all variants of powerpc. Once we mark it as
>> >> > maintained, then we can try to push that patch.
>> >> 
>> >> Enabling the feature is mandatory even on nightly or with
>> >> RUSTC_BOOTSTRAP=1, otherwise no asm!() macro can be called and so the
>> >> kernel crate can’t be built.
>> >> 
>> > The stable support is available on nightly.
>> > Refer https://github.com/rust-lang/rust/pull/147996
>> 
>> In that case you should add the feature with a comment that it's needed for PPC
>> only and is stable in 1.95.
>> 
>> Best,
>> Gary
>> 
> There are some other build errors apart from this on 1.85. So few months
> back in the meeting with LLVM team we concluded that for sometime
> powerpc will be ahead of other archs at 1.95 till others catch up.
>

Is that LLVM 22 being relied on?

If that's the case, you should also gate PPC with CONFIG_RUSTC_LLVM_VERSION.
It's possible to build a Rust with older LLVM versions.

Best,
Gary