On Mon Jul 6, 2026 at 7:34 AM CEST, Alistair Popple wrote:
> @@ -86,15 +90,34 @@ fn probe<'bound>(
> // (`try_pin_init!()` initializes fields in declaration
> order), lives at a pinned
> // stable address, and is dropped after `gpu` (struct field
> drop order).
> gpu <- Gpu::new(pdev, unsafe { &*core::ptr::from_ref(bar) }),
> - _reg: auxiliary::Registration::new(
> - pdev.as_ref(),
> - c"nova-drm",
> - // TODO[XARR]: Use XArray or perhaps IDA for proper ID
> allocation/recycling. For
> - // now, use a simple atomic counter that never recycles
> IDs.
> - AUXILIARY_ID_COUNTER.fetch_add(1, Relaxed),
> - crate::MODULE_NAME,
> - (),
> - )?,
> +
> + // SAFETY:
> + // - `NovaCore` is dropped when the device is unbound; i.e.
> + // `mem::forget()` is never called on it.
> + // - `gpu` is initialized above, lives at a pinned stable
> + // address, and is dropped after `_reg` (struct field drop
> + // order).
> + _reg: unsafe {
> + auxiliary::Registration::new_with_lt(
> + pdev.as_ref(),
> + c"nova-drm",
> + // TODO[XARR]: Use XArray or perhaps IDA for proper
> ID allocation/recycling.
> + // For now, use a simple atomic counter that never
> recycles IDs.
> + AUXILIARY_ID_COUNTER.fetch_add(1, Relaxed),
> + crate::MODULE_NAME,
> + NovaCoreApi {
> + // TODO: Use `&gpu` self-referential pin-init
> syntax once available.
> + //
> + // SAFETY: `gpu` is initialized before this
> expression is evaluated
> + // (`try_pin_init!()` initializes fields in
> declaration order), lives at
> + // a pinned stable address, and is dropped after
> `_reg` (struct field
> + // drop order).
> + gpu: Pin::new_unchecked(
> +
> &*core::ptr::from_ref(gpu.as_ref().get_ref()),
> + ),
Hm...it's a bit messy to have this justified in two separate places. It would be
better to have separate unsafe blocks for this until pin-init solves this
properly. So, let's just do this.
+ _reg: {
+ // SAFETY: `gpu` is initialized before this expression is
evaluated
+ // (`try_pin_init!()` initializes fields in declaration
order), lives at
+ // a pinned stable address, and is dropped after `_reg`
(struct field
+ // drop order).
+ let gpu = unsafe {
+ Pin::new_unchecked(
+ &*core::ptr::from_ref(gpu.as_ref().get_ref()),
+ )
+ };
+
+ // SAFETY: `NovaCore` is dropped when the device is
unbound; i.e.
+ // `mem::forget()` is never called on it.
+ unsafe {
+ auxiliary::Registration::new_with_lt(
+ pdev.as_ref(),
+ c"nova-drm",
+ // TODO[XARR]: Use XArray or perhaps IDA for
proper ID allocation/recycling.
+ // For now, use a simple atomic counter that never
recycles IDs.
+ AUXILIARY_ID_COUNTER.fetch_add(1, Relaxed),
+ crate::MODULE_NAME,
+ NovaCoreApi { gpu },
+ )?
+ }
},
