On Fri, Apr 24, 2026, at 11:43, Link Mauve wrote:
On Fri, Apr 24, 2026 at 10:14:25AM +0100, David Laight wrote:
On Fri, 24 Apr 2026 11:17:40 +0530 "Mukesh Kumar Chaurasiya (IBM)" mkchauras@gmail.com wrote:
From: Link Mauve linkmauve@linkmauve.fr
The core crate currently depends on these two functions for i64/u64/ i128/u128/core::time::Duration formatting, but we shouldn’t use that in the kernel so let’s panic if they are ever called.
Ugg. Surely you can make it a link-time failure? Or change the underlying code to avoid the divide.
This is currently a link-time failure, which means if any of the core crate or drm_panic_qr are linked in, the kernel will fail to link.
And since we rely on core, that means no kernel can be built on PowerPC without this patch.
A possible solution would be to change the core crate to not divide u64s, but the last time I tried to do that I couldn’t quite figure out how to do formatting without it, maybe I will just open an issue against Rust.
I think you just need to rewrite the patch description, it appears that everyone misunderstands what you are doing in the patch:
Like on arm32, normal kernel code will continue to cause a link failure the same way in Rust as it does in C, and your patch does not change that. When you (or Link Mauve) "let's panic", I assume this is was just a mistake in summarizing the logic that turns the unreachable code from the Rust core crate into a runtime assertion since it would be impossible to link the kernel otherwise.
Silently turning a 64-bit division into a panic() for normal code would of course be unacceptable, but that's not what you are doing here.
Arnd