6 files changed, 386 insertions, 7 deletions
diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
index cf7ad950dc1e24..b2bdd4d8c958af 100644
--- a/rust/macros/helpers.rs
+++ b/rust/macros/helpers.rs
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
-use proc_macro::{token_stream, TokenTree};
+use proc_macro::{token_stream, Group, TokenTree};
 
 pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
     if let Some(TokenTree::Ident(ident)) = it.next() {
@@ -56,6 +56,14 @@ pub(crate) fn expect_string_ascii(it: &mut token_stream::IntoIter) -> String {
     string
 }
 
+pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
+    if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") {
+        group
+    } else {
+        panic!("Expected Group");
+    }
+}
+
 pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
     if it.next().is_some() {
         panic!("Expected end");
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
index c1d385e345b96d..3fc74cb4ea1903 100644
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -2,9 +2,13 @@
 
 //! Crate for all kernel procedural macros.
 
+#[macro_use]
+mod quote;
 mod concat_idents;
 mod helpers;
 mod module;
+mod pin_data;
+mod pinned_drop;
 mod vtable;
 
 use proc_macro::TokenStream;
@@ -166,3 +170,79 @@ pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
 pub fn concat_idents(ts: TokenStream) -> TokenStream {
     concat_idents::concat_idents(ts)
 }
+
+/// Used to specify the pinning information of the fields of a struct.
+///
+/// This is somewhat similar in purpose as
+/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
+/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
+/// field you want to structurally pin.
+///
+/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
+/// then `#[pin]` directs the type of initializer that is required.
+///
+/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
+/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
+/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
+///
+/// # Examples
+///
+/// ```rust,ignore
+/// #[pin_data]
+/// struct DriverData {
+///     #[pin]
+///     queue: Mutex<Vec<Command>>,
+///     buf: Box<[u8; 1024 * 1024]>,
+/// }
+/// ```
+///
+/// ```rust,ignore
+/// #[pin_data(PinnedDrop)]
+/// struct DriverData {
+///     #[pin]
+///     queue: Mutex<Vec<Command>>,
+///     buf: Box<[u8; 1024 * 1024]>,
+///     raw_info: *mut Info,
+/// }
+///
+/// #[pinned_drop]
+/// impl PinnedDrop for DriverData {
+///     fn drop(self: Pin<&mut Self>) {
+///         unsafe { bindings::destroy_info(self.raw_info) };
+///     }
+/// }
+/// ```
+///
+/// [`pin_init!`]: ../kernel/macro.pin_init.html
+//  ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
+#[proc_macro_attribute]
+pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
+    pin_data::pin_data(inner, item)
+}
+
+/// Used to implement `PinnedDrop` safely.
+///
+/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
+///
+/// # Examples
+///
+/// ```rust,ignore
+/// #[pin_data(PinnedDrop)]
+/// struct DriverData {
+///     #[pin]
+///     queue: Mutex<Vec<Command>>,
+///     buf: Box<[u8; 1024 * 1024]>,
+///     raw_info: *mut Info,
+/// }
+///
+/// #[pinned_drop]
+/// impl PinnedDrop for DriverData {
+///     fn drop(self: Pin<&mut Self>) {
+///         unsafe { bindings::destroy_info(self.raw_info) };
+///     }
+/// }
+/// ```
+#[proc_macro_attribute]
+pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
+    pinned_drop::pinned_drop(args, input)
+}
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index a7e363c2b04442..fb1244f8c2e694 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs
@@ -1,9 +1,27 @@
 // SPDX-License-Identifier: GPL-2.0
 
 use crate::helpers::*;
-use proc_macro::{token_stream, Literal, TokenStream, TokenTree};
+use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree};
 use std::fmt::Write;
 
+fn expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String> {
+    let group = expect_group(it);
+    assert_eq!(group.delimiter(), Delimiter::Bracket);
+    let mut values = Vec::new();
+    let mut it = group.stream().into_iter();
+
+    while let Some(val) = try_string(&mut it) {
+        assert!(val.is_ascii(), "Expected ASCII string");
+        values.push(val);
+        match it.next() {
+            Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
+            None => break,
+            _ => panic!("Expected ',' or end of array"),
+        }
+    }
+    values
+}
+
 struct ModInfoBuilder<'a> {
     module: &'a str,
     counter: usize,
@@ -78,7 +96,7 @@ struct ModuleInfo {
     name: String,
     author: Option<String>,
     description: Option<String>,
-    alias: Option<String>,
+    alias: Option<Vec<String>>,
 }
 
 impl ModuleInfo {
@@ -112,7 +130,7 @@ impl ModuleInfo {
                 "author" => info.author = Some(expect_string(it)),
                 "description" => info.description = Some(expect_string(it)),
                 "license" => info.license = expect_string_ascii(it),
-                "alias" => info.alias = Some(expect_string_ascii(it)),
+                "alias" => info.alias = Some(expect_string_array(it)),
                 _ => panic!(
                     "Unknown key \"{}\". Valid keys are: {:?}.",
                     key, EXPECTED_KEYS
@@ -163,8 +181,10 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
         modinfo.emit("description", &description);
     }
     modinfo.emit("license", &info.license);
-    if let Some(alias) = info.alias {
-        modinfo.emit("alias", &alias);
+    if let Some(aliases) = info.alias {
+        for alias in aliases {
+            modinfo.emit("alias", &alias);
+        }
     }
 
     // Built-in modules also export the `file` modinfo string.
@@ -258,7 +278,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                         return 0;
                     }}
                     Err(e) => {{
-                        return e.to_kernel_errno();
+                        return e.to_errno();
                     }}
                 }}
             }}
diff --git a/rust/macros/pin_data.rs b/rust/macros/pin_data.rs
new file mode 100644
index 00000000000000..954149d771813c
--- /dev/null
+++ b/rust/macros/pin_data.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use proc_macro::{Punct, Spacing, TokenStream, TokenTree};
+
+pub(crate) fn pin_data(args: TokenStream, input: TokenStream) -> TokenStream {
+    // This proc-macro only does some pre-parsing and then delegates the actual parsing to
+    // `kernel::__pin_data!`.
+    //
+    // In here we only collect the generics, since parsing them in declarative macros is very
+    // elaborate. We also do not need to analyse their structure, we only need to collect them.
+
+    // `impl_generics`, the declared generics with their bounds.
+    let mut impl_generics = vec![];
+    // Only the names of the generics, without any bounds.
+    let mut ty_generics = vec![];
+    // Tokens not related to the generics e.g. the `impl` token.
+    let mut rest = vec![];
+    // The current level of `<`.
+    let mut nesting = 0;
+    let mut toks = input.into_iter();
+    // If we are at the beginning of a generic parameter.
+    let mut at_start = true;
+    for tt in &mut toks {
+        match tt.clone() {
+            TokenTree::Punct(p) if p.as_char() == '<' => {
+                if nesting >= 1 {
+                    impl_generics.push(tt);
+                }
+                nesting += 1;
+            }
+            TokenTree::Punct(p) if p.as_char() == '>' => {
+                if nesting == 0 {
+                    break;
+                } else {
+                    nesting -= 1;
+                    if nesting >= 1 {
+                        impl_generics.push(tt);
+                    }
+                    if nesting == 0 {
+                        break;
+                    }
+                }
+            }
+            tt => {
+                if nesting == 1 {
+                    match &tt {
+                        TokenTree::Ident(i) if i.to_string() == "const" => {}
+                        TokenTree::Ident(_) if at_start => {
+                            ty_generics.push(tt.clone());
+                            ty_generics.push(TokenTree::Punct(Punct::new(',', Spacing::Alone)));
+                            at_start = false;
+                        }
+                        TokenTree::Punct(p) if p.as_char() == ',' => at_start = true,
+                        TokenTree::Punct(p) if p.as_char() == '\'' && at_start => {
+                            ty_generics.push(tt.clone());
+                        }
+                        _ => {}
+                    }
+                }
+                if nesting >= 1 {
+                    impl_generics.push(tt);
+                } else if nesting == 0 {
+                    rest.push(tt);
+                }
+            }
+        }
+    }
+    rest.extend(toks);
+    // This should be the body of the struct `{...}`.
+    let last = rest.pop();
+    quote!(::kernel::__pin_data! {
+        parse_input:
+        @args(#args),
+        @sig(#(#rest)*),
+        @impl_generics(#(#impl_generics)*),
+        @ty_generics(#(#ty_generics)*),
+        @body(#last),
+    })
+}
diff --git a/rust/macros/pinned_drop.rs b/rust/macros/pinned_drop.rs
new file mode 100644
index 00000000000000..88fb72b2066047
--- /dev/null
+++ b/rust/macros/pinned_drop.rs
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use proc_macro::{TokenStream, TokenTree};
+
+pub(crate) fn pinned_drop(_args: TokenStream, input: TokenStream) -> TokenStream {
+    let mut toks = input.into_iter().collect::<Vec<_>>();
+    assert!(!toks.is_empty());
+    // Ensure that we have an `impl` item.
+    assert!(matches!(&toks[0], TokenTree::Ident(i) if i.to_string() == "impl"));
+    // Ensure that we are implementing `PinnedDrop`.
+    let mut nesting: usize = 0;
+    let mut pinned_drop_idx = None;
+    for (i, tt) in toks.iter().enumerate() {
+        match tt {
+            TokenTree::Punct(p) if p.as_char() == '<' => {
+                nesting += 1;
+            }
+            TokenTree::Punct(p) if p.as_char() == '>' => {
+                nesting = nesting.checked_sub(1).unwrap();
+                continue;
+            }
+            _ => {}
+        }
+        if i >= 1 && nesting == 0 {
+            // Found the end of the generics, this should be `PinnedDrop`.
+            assert!(
+                matches!(tt, TokenTree::Ident(i) if i.to_string() == "PinnedDrop"),
+                "expected 'PinnedDrop', found: '{:?}'",
+                tt
+            );
+            pinned_drop_idx = Some(i);
+            break;
+        }
+    }
+    let idx = pinned_drop_idx
+        .unwrap_or_else(|| panic!("Expected an `impl` block implementing `PinnedDrop`."));
+    // Fully qualify the `PinnedDrop`, as to avoid any tampering.
+    toks.splice(idx..idx, quote!(::kernel::init::));
+    // Take the `{}` body and call the declarative macro.
+    if let Some(TokenTree::Group(last)) = toks.pop() {
+        let last = last.stream();
+        quote!(::kernel::__pinned_drop! {
+            @impl_sig(#(#toks)*),
+            @impl_body(#last),
+        })
+    } else {
+        TokenStream::from_iter(toks)
+    }
+}
diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs
new file mode 100644
index 00000000000000..c8e08b3c1e4cfb
--- /dev/null
+++ b/rust/macros/quote.rs
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use proc_macro::{TokenStream, TokenTree};
+
+pub(crate) trait ToTokens {
+    fn to_tokens(&self, tokens: &mut TokenStream);
+}
+
+impl<T: ToTokens> ToTokens for Option<T> {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        if let Some(v) = self {
+            v.to_tokens(tokens);
+        }
+    }
+}
+
+impl ToTokens for proc_macro::Group {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        tokens.extend([TokenTree::from(self.clone())]);
+    }
+}
+
+impl ToTokens for TokenTree {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        tokens.extend([self.clone()]);
+    }
+}
+
+impl ToTokens for TokenStream {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        tokens.extend(self.clone());
+    }
+}
+
+/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
+/// the given span.
+///
+/// This is a similar to the
+/// [`quote_spanned!`](https://docs.rs/quote/latest/quote/macro.quote_spanned.html) macro from the
+/// `quote` crate but provides only just enough functionality needed by the current `macros` crate.
+macro_rules! quote_spanned {
+    ($span:expr => $($tt:tt)*) => {
+    #[allow(clippy::vec_init_then_push)]
+    {
+        let mut tokens = ::std::vec::Vec::new();
+        let span = $span;
+        quote_spanned!(@proc tokens span $($tt)*);
+        ::proc_macro::TokenStream::from_iter(tokens)
+    }};
+    (@proc $v:ident $span:ident) => {};
+    (@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => {
+        let mut ts = ::proc_macro::TokenStream::new();
+        $crate::quote::ToTokens::to_tokens(&$id, &mut ts);
+        $v.extend(ts);
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {
+        for token in $id {
+            let mut ts = ::proc_macro::TokenStream::new();
+            $crate::quote::ToTokens::to_tokens(&token, &mut ts);
+            $v.extend(ts);
+        }
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => {
+        let mut tokens = ::std::vec::Vec::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Parenthesis,
+            ::proc_macro::TokenStream::from_iter(tokens)
+        )));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {
+        let mut tokens = ::std::vec::Vec::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Bracket,
+            ::proc_macro::TokenStream::from_iter(tokens)
+        )));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {
+        let mut tokens = ::std::vec::Vec::new();
+        quote_spanned!(@proc tokens $span $($inner)*);
+        $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(
+            ::proc_macro::Delimiter::Brace,
+            ::proc_macro::TokenStream::from_iter(tokens)
+        )));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident :: $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Joint)
+        ));
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident : $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident , $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new(',', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident @ $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('@', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident ! $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Punct(
+                ::proc_macro::Punct::new('!', ::proc_macro::Spacing::Alone)
+        ));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+    (@proc $v:ident $span:ident $id:ident $($tt:tt)*) => {
+        $v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(stringify!($id), $span)));
+        quote_spanned!(@proc $v $span $($tt)*);
+    };
+}
+
+/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
+/// mixed site span ([`Span::mixed_site()`]).
+///
+/// This is a similar to the [`quote!`](https://docs.rs/quote/latest/quote/macro.quote.html) macro
+/// from the `quote` crate but provides only just enough functionality needed by the current
+/// `macros` crate.
+///
+/// [`Span::mixed_site()`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.mixed_site
+macro_rules! quote {
+    ($($tt:tt)*) => {
+        quote_spanned!(::proc_macro::Span::mixed_site() => $($tt)*)
+    }
+}