Merge pull request #7 from Rust-for-Linux/rust-params

Parameter support

Author: ojeda

Cargo.lock

@@ -4,6 +4,7 @@
 [workspace]
 members = [
     "rust/shlex",
+    "rust/module",
     "rust/kernel",
     "drivers/char/rust_example",
 ]

Cargo.toml

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 # No need for details like `authors` here -- that goes in the modinfo
-# via the `kernel_module!` macro
+# via the `module!` macro
 [package]
 name = "rust_example"
 version = "0.1.0"

drivers/char/rust_example/Cargo.toml

@@ -5,6 +5,26 @@
 
 use kernel::prelude::*;
 
+module!{
+    type: RustExample,
+    name: b"rust_example",
+    author: b"Rust for Linux Contributors",
+    description: b"An example kernel module written in Rust",
+    license: b"GPL v2",
+    params: {
+        my_bool: bool {
+            default: true,
+            permissions: 0,
+            description: b"Example of bool",
+        },
+        my_i32: i32 {
+            default: 42,
+            permissions: 0o644,
+            description: b"Example of i32",
+        },
+    },
+}
+
 struct RustExample {
     message: String,
 }
@@ -13,6 +33,9 @@ impl KernelModule for RustExample {
     fn init() -> KernelResult<Self> {
         println!("Rust Example (init)");
         println!("Am I built-in? {}", !cfg!(MODULE));
+        println!("Parameters:");
+        println!("  my_bool:  {}", my_bool.read());
+        println!("  my_i32:   {}", my_i32.read());
         Ok(RustExample {
             message: "on the heap!".to_owned(),
         })
@@ -26,9 +49,3 @@ impl Drop for RustExample {
     }
 }
 
-kernel_module!(
-    RustExample,
-    author: b"Rust for Linux Contributors",
-    description: b"An example kernel module written in Rust",
-    license: b"GPL v2"
-);

drivers/char/rust_example/src/lib.rs

@@ -9,6 +9,7 @@ publish = false
 
 [dependencies]
 bitflags = "1"
+module = { path = "../module" }
 
 [build-dependencies]
 bindgen = "0.54"

rust/kernel/Cargo.toml

@@ -47,6 +47,8 @@ const INCLUDED_VARS: &[&str] = &[
     "SEEK_CUR",
     "SEEK_END",
     "O_NONBLOCK",
+    "param_ops_bool",
+    "param_ops_int",
 ];
 const OPAQUE_TYPES: &[&str] = &[
     // These need to be opaque because they're both packed and aligned, which rustc

rust/kernel/build.rs

@@ -25,131 +25,6 @@ pub mod user_ptr;
 pub use crate::error::{Error, KernelResult};
 pub use crate::types::{CStr, Mode};
 
-/// Declares the entrypoint for a kernel module. The first argument should be a type which
-/// implements the [`KernelModule`] trait. Also accepts various forms of kernel metadata.
-///
-/// Example:
-/// ```rust,no_run
-/// use kernel::prelude::*;
-///
-/// struct MyKernelModule;
-/// impl KernelModule for MyKernelModule {
-///     fn init() -> KernelResult<Self> {
-///         Ok(MyKernelModule)
-///     }
-/// }
-///
-/// kernel_module!(
-///     MyKernelModule,
-///     author: b"Rust for Linux Contributors",
-///     description: b"My very own kernel module!",
-///     license: b"GPL"
-/// );
-#[macro_export]
-macro_rules! kernel_module {
-    ($module:ty, $($name:ident : $value:expr),*) => {
-        static mut __MOD: Option<$module> = None;
-
-        // Built-in modules are initialized through an initcall pointer
-        //
-        // TODO: should we compile a C file on the fly to avoid duplication?
-        #[cfg(not(MODULE))]
-        #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
-        #[link_section = ".initcall6.init"]
-        #[used]
-        pub static __initcall: extern "C" fn() -> $crate::c_types::c_int = init_module;
-
-        #[cfg(not(MODULE))]
-        #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
-        global_asm!(
-            r#".section ".initcall6.init", "a"
-            __initcall:
-                .long   init_module - .
-                .previous
-            "#
-        );
-
-        // TODO: pass the kernel module name here to generate a unique,
-        // helpful symbol name (the name would also useful for the `modinfo`
-        // issue below).
-        #[no_mangle]
-        pub extern "C" fn init_module() -> $crate::c_types::c_int {
-            match <$module as $crate::KernelModule>::init() {
-                Ok(m) => {
-                    unsafe {
-                        __MOD = Some(m);
-                    }
-                    return 0;
-                }
-                Err(e) => {
-                    return e.to_kernel_errno();
-                }
-            }
-        }
-
-        #[no_mangle]
-        pub extern "C" fn cleanup_module() {
-            unsafe {
-                // Invokes drop() on __MOD, which should be used for cleanup.
-                __MOD = None;
-            }
-        }
-
-        $(
-            $crate::kernel_module!(@attribute $name, $value);
-        )*
-    };
-
-    // TODO: The modinfo attributes below depend on the compiler placing
-    // the variables in order in the .modinfo section, so that you end up
-    // with b"key=value\0" in order in the section. This is a reasonably
-    // standard trick in C, but I'm not sure that rustc guarantees it.
-    //
-    // Ideally we'd be able to use concat_bytes! + stringify_bytes! +
-    // some way of turning a string literal (or at least a string
-    // literal token) into a bytes literal, and get a single static
-    // [u8; * N] with the whole thing, but those don't really exist yet.
-    // Most of the alternatives (e.g. .as_bytes() as a const fn) give
-    // you a pointer, not an array, which isn't right.
-
-    // TODO: `modules.builtin.modinfo` etc. is missing the prefix (module name)
-    (@attribute author, $value:expr) => {
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static AUTHOR_KEY: [u8; 7] = *b"author=";
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static AUTHOR_VALUE: [u8; $value.len()] = *$value;
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static AUTHOR_NUL: [u8; 1] = *b"\0";
-    };
-
-    (@attribute description, $value:expr) => {
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static DESCRIPTION_KEY: [u8; 12] = *b"description=";
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static DESCRIPTION_VALUE: [u8; $value.len()] = *$value;
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static DESCRIPTION_NUL: [u8; 1] = *b"\0";
-    };
-
-    (@attribute license, $value:expr) => {
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static LICENSE_KEY: [u8; 8] = *b"license=";
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static LICENSE_VALUE: [u8; $value.len()] = *$value;
-        #[link_section = ".modinfo"]
-        #[used]
-        pub static LICENSE_NUL: [u8; 1] = *b"\0";
-    };
-}
-
 /// KernelModule is the top level entrypoint to implementing a kernel module. Your kernel module
 /// should implement the `init` method on it, which maps to the `module_init` macro in Linux C API.
 /// You can use this method to do whatever setup or registration your module should do. For any

rust/kernel/src/lib.rs

@@ -7,8 +7,9 @@ pub use alloc::{
     borrow::ToOwned,
 };
 
+pub use module::module;
+
 pub use super::{
-    kernel_module,
     println,
     KernelResult,
     KernelModule,

rust/kernel/src/prelude.rs

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+
+[package]
+name = "module"
+version = "0.1.0"
+authors = ["Rust for Linux Contributors"]
+edition = "2018"
+publish = false
+
+[lib]
+proc-macro = true
+