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-rw-r--r--rust/kernel/allocator.rs64
1 files changed, 64 insertions, 0 deletions
diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
new file mode 100644
index 000000000000..397a3dd57a9b
--- /dev/null
+++ b/rust/kernel/allocator.rs
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Allocator support.
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::ptr;
+
+use crate::bindings;
+
+struct KernelAllocator;
+
+unsafe impl GlobalAlloc for KernelAllocator {
+ unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+ // `krealloc()` is used instead of `kmalloc()` because the latter is
+ // an inline function and cannot be bound to as a result.
+ unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
+ }
+
+ unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+ unsafe {
+ bindings::kfree(ptr as *const core::ffi::c_void);
+ }
+ }
+}
+
+#[global_allocator]
+static ALLOCATOR: KernelAllocator = KernelAllocator;
+
+// `rustc` only generates these for some crate types. Even then, we would need
+// to extract the object file that has them from the archive. For the moment,
+// let's generate them ourselves instead.
+//
+// Note that `#[no_mangle]` implies exported too, nowadays.
+#[no_mangle]
+fn __rust_alloc(size: usize, _align: usize) -> *mut u8 {
+ unsafe { bindings::krealloc(core::ptr::null(), size, bindings::GFP_KERNEL) as *mut u8 }
+}
+
+#[no_mangle]
+fn __rust_dealloc(ptr: *mut u8, _size: usize, _align: usize) {
+ unsafe { bindings::kfree(ptr as *const core::ffi::c_void) };
+}
+
+#[no_mangle]
+fn __rust_realloc(ptr: *mut u8, _old_size: usize, _align: usize, new_size: usize) -> *mut u8 {
+ unsafe {
+ bindings::krealloc(
+ ptr as *const core::ffi::c_void,
+ new_size,
+ bindings::GFP_KERNEL,
+ ) as *mut u8
+ }
+}
+
+#[no_mangle]
+fn __rust_alloc_zeroed(size: usize, _align: usize) -> *mut u8 {
+ unsafe {
+ bindings::krealloc(
+ core::ptr::null(),
+ size,
+ bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+ ) as *mut u8
+ }
+}