On Fri, 2025-12-05 at 09:35 +0900, Alexandre Courbot wrote:
> With one caveat: `new` now returns a 4K object on the stack, which we
> definitely want to avoid. So maybe we can have a wrapper for things we
> want to align the 4K:
>
> #[repr(C)]
> pub(crate) struct GspPageAligned<T> {
> pub(crate) inner: T,
> padding: [u8; GSP_PAGE_SIZE - core::mem::size_of::<T>()],
> }
This doesn't seem to work.
error: generic parameters may not be used in const operations
--> drivers/gpu/nova-core/gsp/fw.rs:894:56
|
894 | ...::mem::size_of::<T>()],
| ^ cannot perform const operation using `T`
|
I've tried different things and they all generate various compilation errors.
I'll just post a v3 with my version, and then you can experiment with it to see
if you can get
GspPageAligned aligned to work on top of it.
>
> We would then allocate the CoherentAllocation using a
> `GspPageAligned<GspArgumentsCached>`, and initialize its useful data
> with:
>
> dma_write!(rmargs[0].inner = fw::GspArgumentsCached::new(&cmdq))?;
So I assume you mean this:
let rmargs =
CoherentAllocation::<GspPageAligned<GspArgumentsCached>>::alloc_coherent(
dev,
1,
GFP_KERNEL | __GFP_ZERO,
)?;
dma_write!(rmargs[0].inner = fw::GspArgumentsCached::new(&cmdq))?;
