On Thu, Mar 06, 2025 at 12:31:14AM +0000, Benno Lossin wrote:
> On Tue Mar 4, 2025 at 6:34 PM CET, Danilo Krummrich wrote:
>
> > +#[macro_export]
> > +macro_rules! module_firmware {
> > + ($($builder:tt)*) => {
>
> This should probably be `$builder:expr` instead.
That doesn't work, the compiler then complains, since it's not an expression:
193 | static __MODULE_FIRMWARE: [u8; $builder::create(__module_name()).build_length()] =
| ^^ expected one of `.`, `?`, `]`, or an operator
`ty` doesn't work either, since then the compiler expects the caller to add the
const generic, which we want the macro to figure out instead.
>
> > +
> > + #[cfg(not(MODULE))]
> > + const fn __module_name() -> &'static kernel::str::CStr {
> > + <LocalModule as kernel::ModuleMetadata>::NAME
>
> Please either use `::kernel::` or `$crate::` instead of `kernel::`.
Good catch, thanks.
>
> Hmm, I am not 100% comfortable with the `LocalModule` way of accessing
> the current module for some reason, no idea if there is a rational
> argument behind that, but it just doesn't sit right with me.
>
> Essentially you're doing this for convenience, right? So you don't want
> to have to repeat the name of the module type every time?
No, it's really that I can't know the type name here, please see the previous
patch commit message that introduces `LocalModule` for explanation.
>
> > + }
> > +
> > + #[cfg(MODULE)]
> > + const fn __module_name() -> &'static kernel::str::CStr {
> > + kernel::c_str!("")
>
> Ditto.
>
> > + }
>
> Are these two functions used outside of the `static` below? If no, then
> you can just move them into the static? You can also probably use a
> `const` instead of a function, that way you only have 4 lines instead
> of 8.
Is this what you're proposing?
#[macro_export]
macro_rules! module_firmware {
($($builder:tt)*) => {
const __MODULE_FIRMWARE_PREFIX: &'static $crate::str::CStr = if cfg!(MODULE) {
$crate::c_str!("")
} else {
<LocalModule as $crate::ModuleMetadata>::NAME
};
#[link_section = ".modinfo"]
#[used]
static __MODULE_FIRMWARE: [u8; $($builder)*::create(__MODULE_FIRMWARE_PREFIX)
.build_length()] = $($builder)*::create(__MODULE_FIRMWARE_PREFIX).build();
};
}
