yuffie 0.0.1

A library for creating UEFI applications, libraries, and drivers
Documentation 
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// SPDX-License-Identifier: BSD-2-Clause-Patent
// SPDX-FileCopyrightText: 2024 System76, Inc.

//! The memory allocator to use with Rust.

use core::ptr::NonNull;

use crate::mem::MemoryType;
use crate::table::BootServices;

#[global_allocator]
static ALLOCATOR: Allocator = Allocator;

// XXX: Put in `lib.rs`?
// TODO: Set to `None` on `ExitBootServices`
/// The Boot Services table holds the functions for memory allocation.
static mut BOOT_SERVICES: Option<NonNull<BootServices>> = None;

/// Save a reference to the Boot Services table.
pub(crate) fn init(bs: &mut BootServices) {
    unsafe {
        BOOT_SERVICES = NonNull::new(bs as *mut _);
    }
}

/// A convenience function to access the boot services table.
unsafe fn boot_services() -> NonNull<BootServices> {
    BOOT_SERVICES.expect("boot services not available")
}

pub struct Allocator;

unsafe impl core::alloc::GlobalAlloc for Allocator {
    unsafe fn alloc(&self, layout: core::alloc::Layout) -> *mut u8 {
        // TODO: Allow other memory types
        boot_services()
            .as_ref()
            .allocate_pool(MemoryType::LOADER_DATA, layout.size())
            .expect("failed to allocate memory")
    }

    unsafe fn dealloc(&self, ptr: *mut u8, _layout: core::alloc::Layout) {
        boot_services().as_ref().free_pool(ptr).expect("failed to free memory");
    }
}