Remove doors_alloc

With the current Rust nightly (2023-06-01 as of this writing), using
`-Zbuild-std` to recompile the `core` and `alloc` crates while enabling
the `no_global_oom_handling` cfg now works properly. Therefore there is
no further need for the `doors_alloc` hack, which involved manually
copying the source for `alloc` and adding it as a Cargo dependency.

It is still not clear what change on the Rust/Cargo end fixed the
bug that previously blocked using `-Zbuild-std` to set the cfg (at the
time, trying to enable the cfg resulted in large numbers of mysterious
"duplicate lang item" errors). Maybe rust-lang/rust#110649 is related.

kernel/.cargo/config.toml

@@ -1,3 +1,6 @@
 [build]
 target = "x86_64-unknown-none"
 rustflags = "-C relocation-model=static -C link-arg=-Tlink.ld --cfg no_global_oom_handling"
+
+[unstable]
+build-std = ["core", "alloc"]

kernel/Cargo.toml

@@ -27,5 +27,4 @@ rustflags = ["--cfg", "doors_test"]
 lock_api = "0.4.9"
 x86_64 = "0.14.10"
 linked_list_allocator = { version = "0.10.5", default-features = false }
-doors_alloc = { path = "../doors_alloc" }
 paste = "1.0.12"

kernel/src/errno.rs

@@ -178,8 +178,8 @@ impl From<core::alloc::AllocError> for Errno {
     }
 }
 
-impl From<doors_alloc::collections::TryReserveError> for Errno {
-    fn from(_value: doors_alloc::collections::TryReserveError) -> Self {
+impl From<alloc::collections::TryReserveError> for Errno {
+    fn from(_value: alloc::collections::TryReserveError) -> Self {
         Errno::ENOMEM
     }
 }

kernel/src/fs/filesystem.rs

@@ -1,6 +1,6 @@
 //! Defines the basic interface provided by filesystem implementations.
 
-use doors_alloc::sync::{Arc, Weak};
+use alloc::sync::Weak;
 
 use crate::errno::Errno;
 use crate::sync::Spinlock;

kernel/src/fs/initrd.rs

@@ -144,7 +144,7 @@ impl FsImpl for Initrd {
 mod tests {
     use crate::errno::Errno;
     use crate::fs::filesystem;
-    use doors_alloc::sync::Arc;
+    use crate::util::alloc::*;
     fn check_file_contents(f: filesystem::FsTreePtr, s: &str) {
         let mut buffer: [u8; 1024] = [0; 1024];
         f.read_exact(0, &mut buffer[..s.len()]).unwrap();

kernel/src/hw/abstraction/timer.rs

@@ -182,7 +182,6 @@ pub static TIMER: Timer<PIT> = Timer {
 
 declare_test!(timer_basic, {
     use core::sync::atomic::*;
-    use doors_alloc::sync::Arc;
     let counter = Arc::try_new(AtomicI32::new(0)).unwrap();
     for i in (0..10).rev() {
         let copy = Arc::clone(&counter);

kernel/src/loader.rs

@@ -1,6 +1,5 @@
 //! The program loader.
 
-use doors_alloc::sync::Arc;
 use x86_64::structures::paging::{Page, PageTableFlags, Size4KiB};
 use x86_64::VirtAddr;
 

kernel/src/main.rs

@@ -11,6 +11,8 @@
 //!
 //! The Doors kernel.
 
+extern crate alloc;
+
 use core::panic::PanicInfo;
 use core::sync::atomic::{AtomicI32, Ordering};
 

kernel/src/thread.rs

@@ -8,13 +8,12 @@ use crate::mm::virt::PageDirectory;
 use crate::sync::{InterruptSafeSpinlock, Spinlock};
 use crate::util::alloc::*;
 use crate::util::singleton::InterruptSafeSingleton;
+use alloc::alloc::{alloc, alloc_zeroed, Layout};
 use core::arch::global_asm;
 use core::cell::UnsafeCell;
 use core::ptr::NonNull;
 use core::sync::atomic::*;
 use core::{mem, ptr};
-use doors_alloc::alloc::{alloc, alloc_zeroed, Layout};
-use doors_alloc::sync::Arc;
 use x86_64::instructions::interrupts::are_enabled as interrupts_are_enabled;
 use x86_64::VirtAddr;
 

kernel/src/util/alloc.rs

@@ -8,10 +8,10 @@
 //! This will automatically bring [`String`], [`Vec`], [`Box`], and [`Arc`] into scope as well.
 
 use crate::errno::Errno;
-pub use doors_alloc::boxed::Box;
-pub use doors_alloc::string::String;
-pub use doors_alloc::sync::Arc;
-pub use doors_alloc::vec::Vec;
+pub use alloc::boxed::Box;
+pub use alloc::string::String;
+pub use alloc::sync::Arc;
+pub use alloc::vec::Vec;
 
 /// Represents an error that occurred with the [`try_push`](VecExt::try_push) method.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]