1 files changed, 133 insertions, 0 deletions
diff --git a/rust/kernel/build.rs b/rust/kernel/build.rs
new file mode 100644
index 000000000000..b9085a6367b4
--- /dev/null
+++ b/rust/kernel/build.rs
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use std::path::PathBuf;
+use std::env;
+
+const INCLUDED_TYPES: &[&str] = &["file_system_type", "mode_t", "umode_t", "ctl_table"];
+const INCLUDED_FUNCTIONS: &[&str] = &[
+    "cdev_add",
+    "cdev_init",
+    "cdev_del",
+    "register_filesystem",
+    "unregister_filesystem",
+    "krealloc",
+    "kfree",
+    "mount_nodev",
+    "kill_litter_super",
+    "register_sysctl",
+    "unregister_sysctl_table",
+    "access_ok",
+    "_copy_to_user",
+    "_copy_from_user",
+    "alloc_chrdev_region",
+    "unregister_chrdev_region",
+    "wait_for_random_bytes",
+    "get_random_bytes",
+    "rng_is_initialized",
+    "printk",
+    "add_device_randomness",
+];
+const INCLUDED_VARS: &[&str] = &[
+    "EINVAL",
+    "ENOMEM",
+    "ESPIPE",
+    "EFAULT",
+    "EAGAIN",
+    "__this_module",
+    "FS_REQUIRES_DEV",
+    "FS_BINARY_MOUNTDATA",
+    "FS_HAS_SUBTYPE",
+    "FS_USERNS_MOUNT",
+    "FS_RENAME_DOES_D_MOVE",
+    "BINDINGS_GFP_KERNEL",
+    "KERN_INFO",
+    "VERIFY_WRITE",
+    "LINUX_VERSION_CODE",
+    "SEEK_SET",
+    "SEEK_CUR",
+    "SEEK_END",
+    "O_NONBLOCK",
+];
+const OPAQUE_TYPES: &[&str] = &[
+    // These need to be opaque because they're both packed and aligned, which rustc
+    // doesn't support yet. See https://github.com/rust-lang/rust/issues/59154
+    // and https://github.com/rust-lang/rust-bindgen/issues/1538
+    "desc_struct",
+    "xregs_state",
+];
+
+// Takes the CFLAGS from the kernel Makefile and changes all the include paths to be absolute
+// instead of relative.
+fn prepare_cflags(cflags: &str, kernel_dir: &str) -> Vec<String> {
+    let cflag_parts = shlex::split(&cflags).unwrap();
+    let mut cflag_iter = cflag_parts.iter();
+    let mut kernel_args = vec![];
+    while let Some(arg) = cflag_iter.next() {
+        // TODO: bindgen complains
+        if arg.starts_with("-Wp,-MMD") {
+            continue;
+        }
+
+        if arg.starts_with("-I") && !arg.starts_with("-I/") {
+            kernel_args.push(format!("-I{}/{}", kernel_dir, &arg[2..]));
+        } else if arg == "-include" {
+            kernel_args.push(arg.to_string());
+            let include_path = cflag_iter.next().unwrap();
+            if include_path.starts_with('/') {
+                kernel_args.push(include_path.to_string());
+            } else {
+                kernel_args.push(format!("{}/{}", kernel_dir, include_path));
+            }
+        } else {
+            kernel_args.push(arg.to_string());
+        }
+    }
+    kernel_args
+}
+
+fn main() {
+    println!("cargo:rerun-if-env-changed=CC");
+    println!("cargo:rerun-if-env-changed=RUST_BINDGEN_CFLAGS");
+
+    let kernel_dir = "../../";
+    let cflags = env::var("RUST_BINDGEN_CFLAGS")
+        .expect("Must be invoked from kernel makefile");
+
+    let kernel_args = prepare_cflags(&cflags, &kernel_dir);
+
+    let target = env::var("TARGET").unwrap();
+
+    let mut builder = bindgen::Builder::default()
+        .use_core()
+        .ctypes_prefix("c_types")
+        .derive_default(true)
+        .size_t_is_usize(true)
+        .rustfmt_bindings(true);
+
+    builder = builder.clang_arg(format!("--target={}", target));
+    for arg in kernel_args.iter() {
+        builder = builder.clang_arg(arg.clone());
+    }
+
+    println!("cargo:rerun-if-changed=src/bindings_helper.h");
+    builder = builder.header("src/bindings_helper.h");
+
+    for t in INCLUDED_TYPES {
+        builder = builder.whitelist_type(t);
+    }
+    for f in INCLUDED_FUNCTIONS {
+        builder = builder.whitelist_function(f);
+    }
+    for v in INCLUDED_VARS {
+        builder = builder.whitelist_var(v);
+    }
+    for t in OPAQUE_TYPES {
+        builder = builder.opaque_type(t);
+    }
+    let bindings = builder.generate().expect("Unable to generate bindings");
+
+    let out_path = PathBuf::from("src/bindings_gen.rs");
+    bindings
+        .write_to_file(out_path)
+        .expect("Couldn't write bindings!");
+}