std: move allocators to `sys`

1 files changed, 49 insertions, 0 deletions

diff --git a/library/std/src/sys/alloc/uefi.rs b/library/std/src/sys/alloc/uefi.rs
new file mode 100644
index 00000000000..5221876e908
--- /dev/null
+++ b/library/std/src/sys/alloc/uefi.rs
@@ -0,0 +1,49 @@
+//! Global Allocator for UEFI.
+//! Uses [r-efi-alloc](https://crates.io/crates/r-efi-alloc)
+
+use r_efi::protocols::loaded_image;
+
+use crate::alloc::{GlobalAlloc, Layout, System};
+use crate::sync::OnceLock;
+use crate::sys::pal::helpers;
+
+#[stable(feature = "alloc_system_type", since = "1.28.0")]
+unsafe impl GlobalAlloc for System {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        static EFI_MEMORY_TYPE: OnceLock<u32> = OnceLock::new();
+
+        // Return null pointer if boot services are not available
+        if crate::os::uefi::env::boot_services().is_none() {
+            return crate::ptr::null_mut();
+        }
+
+        // If boot services is valid then SystemTable is not null.
+        let system_table = crate::os::uefi::env::system_table().as_ptr().cast();
+
+        // Each loaded image has an image handle that supports `EFI_LOADED_IMAGE_PROTOCOL`. Thus, this
+        // will never fail.
+        let mem_type = EFI_MEMORY_TYPE.get_or_init(|| {
+            let protocol = helpers::image_handle_protocol::<loaded_image::Protocol>(
+                loaded_image::PROTOCOL_GUID,
+            )
+            .unwrap();
+            // Gives allocations the memory type that the data sections were loaded as.
+            unsafe { (*protocol.as_ptr()).image_data_type }
+        });
+
+        // The caller must ensure non-0 layout
+        unsafe { r_efi_alloc::raw::alloc(system_table, layout, *mem_type) }
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        // Do nothing if boot services are not available
+        if crate::os::uefi::env::boot_services().is_none() {
+            return;
+        }
+
+        // If boot services is valid then SystemTable is not null.
+        let system_table = crate::os::uefi::env::system_table().as_ptr().cast();
+        // The caller must ensure non-0 layout
+        unsafe { r_efi_alloc::raw::dealloc(system_table, ptr, layout) }
+    }
+}