Merge tag 'rust-6.6' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda:
 "In terms of lines, most changes this time are on the pinned-init API
  and infrastructure. While we have a Rust version upgrade, and thus a
  bunch of changes from the vendored 'alloc' crate as usual, this time
  those do not account for many lines.

  Toolchain and infrastructure:

   - Upgrade to Rust 1.71.1. This is the second such upgrade, which is a
     smaller jump compared to the last time.

     This version allows us to remove the '__rust_*' allocator functions
     -- the compiler now generates them as expected, thus now our
     'KernelAllocator' is used.

     It also introduces the 'offset_of!' macro in the standard library
     (as an unstable feature) which we will need soon. So far, we were
     using a declarative macro as a prerequisite in some not-yet-landed
     patch series, which did not support sub-fields (i.e. nested
     structs):

         #[repr(C)]
         struct S {
             a: u16,
             b: (u8, u8),
         }

         assert_eq!(offset_of!(S, b.1), 3);

   - Upgrade to bindgen 0.65.1. This is the first time we upgrade its
     version.

     Given it is a fairly big jump, it comes with a fair number of
     improvements/changes that affect us, such as a fix needed to
     support LLVM 16 as well as proper support for '__noreturn' C
     functions, which are now mapped to return the '!' type in Rust:

         void __noreturn f(void); // C
         pub fn f() -> !;         // Rust

   - 'scripts/rust_is_available.sh' improvements and fixes.

     This series takes care of all the issues known so far and adds a
     few new checks to cover for even more cases, plus adds some more
     help texts. All this together will hopefully make problematic
     setups easier to identify and to be solved by users building the
     kernel.

     In addition, it adds a test suite which covers all branches of the
     shell script, as well as tests for the issues found so far.

   - Support rust-analyzer for out-of-tree modules too.

   - Give 'cfg's to rust-analyzer for the 'core' and 'alloc' crates.

   - Drop 'scripts/is_rust_module.sh' since it is not needed anymore.

  Macros crate:

   - New 'paste!' proc macro.

     This macro is a more flexible version of 'concat_idents!': it
     allows the resulting identifier to be used to declare new items and
     it allows to transform the identifiers before concatenating them,
     e.g.

         let x_1 = 42;
         paste!(let [<x _2>] = [<x _1>];);
         assert!(x_1 == x_2);

     The macro is then used for several of the pinned-init API changes
     in this pull.

  Pinned-init API:

   - Make '#[pin_data]' compatible with conditional compilation of
     fields, allowing to write code like:

         #[pin_data]
         pub struct Foo {
             #[cfg(CONFIG_BAR)]
             a: Bar,
             #[cfg(not(CONFIG_BAR))]
             a: Baz,
         }

   - New '#[derive(Zeroable)]' proc macro for the 'Zeroable' trait,
     which allows 'unsafe' implementations for structs where every field
     implements the 'Zeroable' trait, e.g.:

         #[derive(Zeroable)]
         pub struct DriverData {
             id: i64,
             buf_ptr: *mut u8,
             len: usize,
         }

   - Add '..Zeroable::zeroed()' syntax to the 'pin_init!' macro for
     zeroing all other fields, e.g.:

         pin_init!(Buf {
             buf: [1; 64],
             ..Zeroable::zeroed()
         });

   - New '{,pin_}init_array_from_fn()' functions to create array
     initializers given a generator function, e.g.:

         let b: Box<[usize; 1_000]> = Box::init::<Error>(
             init_array_from_fn(|i| i)
         ).unwrap();

         assert_eq!(b.len(), 1_000);
         assert_eq!(b[123], 123);

   - New '{,pin_}chain' methods for '{,Pin}Init<T, E>' that allow to
     execute a closure on the value directly after initialization, e.g.:

         let foo = init!(Foo {
             buf <- init::zeroed()
         }).chain(|foo| {
             foo.setup();
             Ok(())
         });

   - Support arbitrary paths in init macros, instead of just identifiers
     and generic types.

   - Implement the 'Zeroable' trait for the 'UnsafeCell<T>' and
     'Opaque<T>' types.

   - Make initializer values inaccessible after initialization.

   - Make guards in the init macros hygienic.

  'allocator' module:

   - Use 'krealloc_aligned()' in 'KernelAllocator::alloc' preventing
     misaligned allocations when the Rust 1.71.1 upgrade is applied
     later in this pull.

     The equivalent fix for the previous compiler version (where
     'KernelAllocator' is not yet used) was merged into 6.5 already,
     which added the 'krealloc_aligned()' function used here.

   - Implement 'KernelAllocator::{realloc, alloc_zeroed}' for
     performance, using 'krealloc_aligned()' too, which forwards the
     call to the C API.

  'types' module:

   - Make 'Opaque' be '!Unpin', removing the need to add a
     'PhantomPinned' field to Rust structs that contain C structs which
     must not be moved.

   - Make 'Opaque' use 'UnsafeCell' as the outer type, rather than
     inner.

  Documentation:

   - Suggest obtaining the source code of the Rust's 'core' library
     using the tarball instead of the repository.

  MAINTAINERS:

   - Andreas and Alice, from Samsung and Google respectively, are
     joining as reviewers of the "RUST" entry.

  As well as a few other minor changes and cleanups"

* tag 'rust-6.6' of https://github.com/Rust-for-Linux/linux: (42 commits)
  rust: init: update expanded macro explanation
  rust: init: add `{pin_}chain` functions to `{Pin}Init<T, E>`
  rust: init: make `PinInit<T, E>` a supertrait of `Init<T, E>`
  rust: init: implement `Zeroable` for `UnsafeCell<T>` and `Opaque<T>`
  rust: init: add support for arbitrary paths in init macros
  rust: init: add functions to create array initializers
  rust: init: add `..Zeroable::zeroed()` syntax for zeroing all missing fields
  rust: init: make initializer values inaccessible after initializing
  rust: init: wrap type checking struct initializers in a closure
  rust: init: make guards in the init macros hygienic
  rust: add derive macro for `Zeroable`
  rust: init: make `#[pin_data]` compatible with conditional compilation of fields
  rust: init: consolidate init macros
  docs: rust: clarify what 'rustup override' does
  docs: rust: update instructions for obtaining 'core' source
  docs: rust: add command line to rust-analyzer section
  scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`
  rust: bindgen: upgrade to 0.65.1
  rust: enable `no_mangle_with_rust_abi` Clippy lint
  rust: upgrade to Rust 1.71.1
  ...

35 files changed, 1914 insertions, 849 deletions

diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 5561dae94f85..0bbd040f6a55 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -31,8 +31,8 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
-Rust (optional)        1.68.2           rustc --version
-bindgen (optional)     0.56.0           bindgen --version
+Rust (optional)        1.71.1           rustc --version
+bindgen (optional)     0.65.1           bindgen --version
 GNU make               3.82             make --version
 bash                   4.2              bash --version
 binutils               2.25             ld -v
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
index a8931512ed98..f382914f4191 100644
--- a/Documentation/rust/quick-start.rst
+++ b/Documentation/rust/quick-start.rst
@@ -38,7 +38,9 @@ and run::
 
 	rustup override set $(scripts/min-tool-version.sh rustc)
 
-Otherwise, fetch a standalone installer from:
+This will configure your working directory to use the correct version of
+``rustc`` without affecting your default toolchain. If you are not using
+``rustup``, fetch a standalone installer from:
 
 	https://forge.rust-lang.org/infra/other-installation-methods.html#standalone
 
@@ -56,16 +58,17 @@ If ``rustup`` is being used, run::
 The components are installed per toolchain, thus upgrading the Rust compiler
 version later on requires re-adding the component.
 
-Otherwise, if a standalone installer is used, the Rust repository may be cloned
-into the installation folder of the toolchain::
+Otherwise, if a standalone installer is used, the Rust source tree may be
+downloaded into the toolchain's installation folder::
 
-	git clone --recurse-submodules \
-		--branch $(scripts/min-tool-version.sh rustc) \
-		https://github.com/rust-lang/rust \
-		$(rustc --print sysroot)/lib/rustlib/src/rust
+	curl -L "https://static.rust-lang.org/dist/rust-src-$(scripts/min-tool-version.sh rustc).tar.gz" |
+		tar -xzf - -C "$(rustc --print sysroot)/lib" \
+		"rust-src-$(scripts/min-tool-version.sh rustc)/rust-src/lib/" \
+		--strip-components=3
 
 In this case, upgrading the Rust compiler version later on requires manually
-updating this clone.
+updating the source tree (this can be done by removing ``$(rustc --print
+sysroot)/lib/rustlib/src/rust`` then rerunning the above command).
 
 
 libclang
@@ -98,7 +101,24 @@ the ``bindgen`` tool. A particular version is required.
 
 Install it via (note that this will download and build the tool from source)::
 
-	cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen
+	cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen-cli
+
+``bindgen`` needs to find a suitable ``libclang`` in order to work. If it is
+not found (or a different ``libclang`` than the one found should be used),
+the process can be tweaked using the environment variables understood by
+``clang-sys`` (the Rust bindings crate that ``bindgen`` uses to access
+``libclang``):
+
+* ``LLVM_CONFIG_PATH`` can be pointed to an ``llvm-config`` executable.
+
+* Or ``LIBCLANG_PATH`` can be pointed to a ``libclang`` shared library
+  or to the directory containing it.
+
+* Or ``CLANG_PATH`` can be pointed to a ``clang`` executable.
+
+For details, please see ``clang-sys``'s documentation at:
+
+	https://github.com/KyleMayes/clang-sys#environment-variables
 
 
 Requirements: Developing
@@ -179,7 +199,9 @@ be used with many editors to enable syntax highlighting, completion, go to
 definition, and other features.
 
 ``rust-analyzer`` needs a configuration file, ``rust-project.json``, which
-can be generated by the ``rust-analyzer`` Make target.
+can be generated by the ``rust-analyzer`` Make target::
+
+	make LLVM=1 rust-analyzer
 
 
 Configuration
diff --git a/MAINTAINERS b/MAINTAINERS
index 4b8d634f3a4e..9b2f9135e856 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18577,6 +18577,8 @@ R:	Boqun Feng <boqun.feng@gmail.com>
 R:	Gary Guo <gary@garyguo.net>
 R:	Björn Roy Baron <bjorn3_gh@protonmail.com>
 R:	Benno Lossin <benno.lossin@proton.me>
+R:	Andreas Hindborg <a.hindborg@samsung.com>
+R:	Alice Ryhl <aliceryhl@google.com>
 L:	rust-for-linux@vger.kernel.org
 S:	Supported
 W:	https://github.com/Rust-for-Linux/linux
diff --git a/Makefile b/Makefile
index 2fdd8b40b7e0..4f283d915e54 100644
--- a/Makefile
+++ b/Makefile
@@ -467,6 +467,7 @@ export rust_common_flags := --edition=2021 \
 			    -Dclippy::let_unit_value -Dclippy::mut_mut \
 			    -Dclippy::needless_bitwise_bool \
 			    -Dclippy::needless_continue \
+			    -Dclippy::no_mangle_with_rust_abi \
 			    -Wclippy::dbg_macro
 
 KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
@@ -1289,7 +1290,7 @@ prepare0: archprepare
 # All the preparing..
 prepare: prepare0
 ifdef CONFIG_RUST
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh -v
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh
 	$(Q)$(MAKE) $(build)=rust
 endif
 
@@ -1825,7 +1826,7 @@ $(DOC_TARGETS):
 # "Is Rust available?" target
 PHONY += rustavailable
 rustavailable:
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh -v && echo "Rust is available!"
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh && echo "Rust is available!"
 
 # Documentation target
 #
@@ -1859,11 +1860,6 @@ rustfmt:
 rustfmtcheck: rustfmt_flags = --check
 rustfmtcheck: rustfmt
 
-# IDE support targets
-PHONY += rust-analyzer
-rust-analyzer:
-	$(Q)$(MAKE) $(build)=rust $@
-
 # Misc
 # ---------------------------------------------------------------------------
 
@@ -1924,6 +1920,7 @@ help:
 	@echo  '  modules         - default target, build the module(s)'
 	@echo  '  modules_install - install the module'
 	@echo  '  clean           - remove generated files in module directory only'
+	@echo  '  rust-analyzer	  - generate rust-project.json rust-analyzer support file'
 	@echo  ''
 
 __external_modules_error:
@@ -2065,6 +2062,11 @@ quiet_cmd_tags = GEN     $@
 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)
 
+# IDE support targets
+PHONY += rust-analyzer
+rust-analyzer:
+	$(Q)$(MAKE) $(build)=rust $@
+
 # Script to generate missing namespace dependencies
 # ---------------------------------------------------------------------------
 
diff --git a/rust/Makefile b/rust/Makefile
index 30b71af119a2..0d4bb06c5cee 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -329,7 +329,7 @@ quiet_cmd_bindgen = BINDGEN $@
 	$(BINDGEN) $< $(bindgen_target_flags) \
 		--use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \
 		--no-debug '.*' \
-		--size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \
+		-o $@ -- $(bindgen_c_flags_final) -DMODULE \
 		$(bindgen_target_cflags) $(bindgen_target_extra)
 
 $(obj)/bindings/bindings_generated.rs: private bindgen_target_flags = \
@@ -349,8 +349,8 @@ $(obj)/uapi/uapi_generated.rs: $(src)/uapi/uapi_helper.h \
 # given it is `libclang`; but for consistency, future Clang changes and/or
 # a potential future GCC backend for `bindgen`, we disable it too.
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_flags = \
-    --blacklist-type '.*' --whitelist-var '' \
-    --whitelist-function 'rust_helper_.*'
+    --blocklist-type '.*' --allowlist-var '' \
+    --allowlist-function 'rust_helper_.*'
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
     -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
 $(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
@@ -402,12 +402,15 @@ quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L
 	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
 
 rust-analyzer:
-	$(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \
-		$(RUST_LIB_SRC) > $(objtree)/rust-project.json
+	$(Q)$(srctree)/scripts/generate_rust_analyzer.py \
+		--cfgs='core=$(core-cfgs)' --cfgs='alloc=$(alloc-cfgs)' \
+		$(abs_srctree) $(abs_objtree) \
+		$(RUST_LIB_SRC) $(KBUILD_EXTMOD) > \
+		$(if $(KBUILD_EXTMOD),$(extmod_prefix),$(objtree))/rust-project.json
 
 redirect-intrinsics = \
-	__eqsf2 __gesf2 __lesf2 __nesf2 __unordsf2 \
-	__unorddf2 \
+	__addsf3 __eqsf2 __gesf2 __lesf2 __ltsf2 __mulsf3 __nesf2 __unordsf2 \
+	__adddf3 __ledf2 __ltdf2 __muldf3 __unorddf2 \
 	__muloti4 __multi3 \
 	__udivmodti4 __udivti3 __umodti3
 
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index acf22d45e6f2..0b6bf5b6da43 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -16,8 +16,6 @@ use core::ptr::{self, NonNull};
 #[doc(inline)]
 pub use core::alloc::*;
 
-use core::marker::Destruct;
-
 #[cfg(test)]
 mod tests;
 
@@ -41,6 +39,9 @@ extern "Rust" {
     #[rustc_allocator_zeroed]
     #[rustc_nounwind]
     fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
+
+    #[cfg(not(bootstrap))]
+    static __rust_no_alloc_shim_is_unstable: u8;
 }
 
 /// The global memory allocator.
@@ -94,7 +95,14 @@ pub use std::alloc::Global;
 #[must_use = "losing the pointer will leak memory"]
 #[inline]
 pub unsafe fn alloc(layout: Layout) -> *mut u8 {
-    unsafe { __rust_alloc(layout.size(), layout.align()) }
+    unsafe {
+        // Make sure we don't accidentally allow omitting the allocator shim in
+        // stable code until it is actually stabilized.
+        #[cfg(not(bootstrap))]
+        core::ptr::read_volatile(&__rust_no_alloc_shim_is_unstable);
+
+        __rust_alloc(layout.size(), layout.align())
+    }
 }
 
 /// Deallocate memory with the global allocator.
@@ -333,16 +341,12 @@ unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
 
 #[cfg_attr(not(test), lang = "box_free")]
 #[inline]
-#[rustc_const_unstable(feature = "const_box", issue = "92521")]
 // This signature has to be the same as `Box`, otherwise an ICE will happen.
 // When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
 // well.
 // For example if `Box` is changed to  `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
 // this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
-pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Destruct>(
-    ptr: Unique<T>,
-    alloc: A,
-) {
+pub(crate) unsafe fn box_free<T: ?Sized, A: Allocator>(ptr: Unique<T>, alloc: A) {
     unsafe {
         let size = size_of_val(ptr.as_ref());
         let align = min_align_of_val(ptr.as_ref());
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
index 14af9860c36c..c8173cea8317 100644
--- a/rust/alloc/boxed.rs
+++ b/rust/alloc/boxed.rs
@@ -152,16 +152,13 @@ use core::any::Any;
 use core::async_iter::AsyncIterator;
 use core::borrow;
 use core::cmp::Ordering;
-use core::convert::{From, TryFrom};
 use core::error::Error;
 use core::fmt;
 use core::future::Future;
 use core::hash::{Hash, Hasher};
-#[cfg(not(no_global_oom_handling))]
-use core::iter::FromIterator;
-use core::iter::{FusedIterator, Iterator};
+use core::iter::FusedIterator;
 use core::marker::Tuple;
-use core::marker::{Destruct, Unpin, Unsize};
+use core::marker::Unsize;
 use core::mem;
 use core::ops::{
     CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
@@ -218,6 +215,7 @@ impl<T> Box<T> {
     #[inline(always)]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
+    #[rustc_diagnostic_item = "box_new"]
     pub fn new(x: T) -> Self {
         #[rustc_box]
         Box::new(x)
@@ -287,9 +285,7 @@ impl<T> Box<T> {
     #[must_use]
     #[inline(always)]
     pub fn pin(x: T) -> Pin<Box<T>> {
-        (#[rustc_box]
-        Box::new(x))
-        .into()
+        Box::new(x).into()
     }
 
     /// Allocates memory on the heap then places `x` into it,
@@ -381,12 +377,11 @@ impl<T, A: Allocator> Box<T, A> {
     /// ```
     #[cfg(not(no_global_oom_handling))]
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline]
-    pub const fn new_in(x: T, alloc: A) -> Self
+    pub fn new_in(x: T, alloc: A) -> Self
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let mut boxed = Self::new_uninit_in(alloc);
         unsafe {
@@ -411,12 +406,10 @@ impl<T, A: Allocator> Box<T, A> {
     /// # Ok::<(), std::alloc::AllocError>(())
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
+    pub fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
     where
-        T: ~const Destruct,
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let mut boxed = Self::try_new_uninit_in(alloc)?;
         unsafe {
@@ -446,13 +439,12 @@ impl<T, A: Allocator> Box<T, A> {
     /// assert_eq!(*five, 5)
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[cfg(not(no_global_oom_handling))]
     #[must_use]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    pub const fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    pub fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -487,10 +479,9 @@ impl<T, A: Allocator> Box<T, A> {
     /// ```
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    pub const fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    pub fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate(layout)?.cast();
@@ -518,13 +509,12 @@ impl<T, A: Allocator> Box<T, A> {
     ///
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[cfg(not(no_global_oom_handling))]
     // #[unstable(feature = "new_uninit", issue = "63291")]
     #[must_use]
-    pub const fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    pub fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
@@ -559,10 +549,9 @@ impl<T, A: Allocator> Box<T, A> {
     /// [zeroed]: mem::MaybeUninit::zeroed
     #[unstable(feature = "allocator_api", issue = "32838")]
     // #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    pub const fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    pub fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
     where
-        A: ~const Allocator + ~const Destruct,
+        A: Allocator,
     {
         let layout = Layout::new::<mem::MaybeUninit<T>>();
         let ptr = alloc.allocate_zeroed(layout)?.cast();
@@ -578,12 +567,11 @@ impl<T, A: Allocator> Box<T, A> {
     /// construct a (pinned) `Box` in a different way than with [`Box::new_in`].
     #[cfg(not(no_global_oom_handling))]
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[must_use]
     #[inline(always)]
-    pub const fn pin_in(x: T, alloc: A) -> Pin<Self>
+    pub fn pin_in(x: T, alloc: A) -> Pin<Self>
     where
-        A: 'static + ~const Allocator + ~const Destruct,
+        A: 'static + Allocator,
     {
         Self::into_pin(Self::new_in(x, alloc))
     }
@@ -592,8 +580,7 @@ impl<T, A: Allocator> Box<T, A> {
     ///
     /// This conversion does not allocate on the heap and happens in place.
     #[unstable(feature = "box_into_boxed_slice", issue = "71582")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
-    pub const fn into_boxed_slice(boxed: Self) -> Box<[T], A> {
+    pub fn into_boxed_slice(boxed: Self) -> Box<[T], A> {
         let (raw, alloc) = Box::into_raw_with_allocator(boxed);
         unsafe { Box::from_raw_in(raw as *mut [T; 1], alloc) }
     }
@@ -610,12 +597,8 @@ impl<T, A: Allocator> Box<T, A> {
     /// assert_eq!(Box::into_inner(c), 5);
     /// ```
     #[unstable(feature = "box_into_inner", issue = "80437")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn into_inner(boxed: Self) -> T
-    where
-        Self: ~const Destruct,
-    {
+    pub fn into_inner(boxed: Self) -> T {
         *boxed
     }
 }
@@ -829,9 +812,8 @@ impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
     /// assert_eq!(*five, 5)
     /// ```
     #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const unsafe fn assume_init(self) -> Box<T, A> {
+    pub unsafe fn assume_init(self) -> Box<T, A> {
         let (raw, alloc) = Box::into_raw_with_allocator(self);
         unsafe { Box::from_raw_in(raw as *mut T, alloc) }
     }
@@ -864,9 +846,8 @@ impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
     /// }
     /// ```
     #[unstable(feature = "new_uninit", issue = "63291")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn write(mut boxed: Self, value: T) -> Box<T, A> {
+    pub fn write(mut boxed: Self, value: T) -> Box<T, A> {
         unsafe {
             (*boxed).write(value);
             boxed.assume_init()
@@ -1110,9 +1091,8 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     ///
     /// [memory layout]: self#memory-layout
     #[unstable(feature = "allocator_api", issue = "32838")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
+    pub fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
         let (leaked, alloc) = Box::into_unique(b);
         (leaked.as_ptr(), alloc)
     }
@@ -1122,10 +1102,9 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
         issue = "none",
         reason = "use `Box::leak(b).into()` or `Unique::from(Box::leak(b))` instead"
     )]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
     #[doc(hidden)]
-    pub const fn into_unique(b: Self) -> (Unique<T>, A) {
+    pub fn into_unique(b: Self) -> (Unique<T>, A) {
         // Box is recognized as a "unique pointer" by Stacked Borrows, but internally it is a
         // raw pointer for the type system. Turning it directly into a raw pointer would not be
         // recognized as "releasing" the unique pointer to permit aliased raw accesses,
@@ -1183,9 +1162,8 @@ impl<T: ?Sized, A: Allocator> Box<T, A> {
     /// assert_eq!(*static_ref, [4, 2, 3]);
     /// ```
     #[stable(feature = "box_leak", since = "1.26.0")]
-    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
     #[inline]
-    pub const fn leak<'a>(b: Self) -> &'a mut T
+    pub fn leak<'a>(b: Self) -> &'a mut T
     where
         A: 'a,
     {
@@ -1246,16 +1224,16 @@ unsafe impl<#[may_dangle] T: ?Sized, A: Allocator> Drop for Box<T, A> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Default> Default for Box<T> {
     /// Creates a `Box<T>`, with the `Default` value for T.
+    #[inline]
     fn default() -> Self {
-        #[rustc_box]
         Box::new(T::default())
     }
 }
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
-impl<T> const Default for Box<[T]> {
+impl<T> Default for Box<[T]> {
+    #[inline]
     fn default() -> Self {
         let ptr: Unique<[T]> = Unique::<[T; 0]>::dangling();
         Box(ptr, Global)
@@ -1264,8 +1242,8 @@ impl<T> const Default for Box<[T]> {
 
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "default_box_extra", since = "1.17.0")]
-#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
-impl const Default for Box<str> {
+impl Default for Box<str> {
+    #[inline]
     fn default() -> Self {
         // SAFETY: This is the same as `Unique::cast<U>` but with an unsized `U = str`.
         let ptr: Unique<str> = unsafe {
@@ -1461,8 +1439,7 @@ impl<T> From<T> for Box<T> {
 }
 
 #[stable(feature = "pin", since = "1.33.0")]
-#[rustc_const_unstable(feature = "const_box", issue = "92521")]
-impl<T: ?Sized, A: Allocator> const From<Box<T, A>> for Pin<Box<T, A>>
+impl<T: ?Sized, A: Allocator> From<Box<T, A>> for Pin<Box<T, A>>
 where
     A: 'static,
 {
@@ -1482,9 +1459,36 @@ where
     }
 }
 
+/// Specialization trait used for `From<&[T]>`.
+#[cfg(not(no_global_oom_handling))]
+trait BoxFromSlice<T> {
+    fn from_slice(slice: &[T]) -> Self;
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Clone> BoxFromSlice<T> for Box<[T]> {
+    #[inline]
+    default fn from_slice(slice: &[T]) -> Self {
+        slice.to_vec().into_boxed_slice()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Copy> BoxFromSlice<T> for Box<[T]> {
+    #[inline]
+    fn from_slice(slice: &[T]) -> Self {
+        let len = slice.len();
+        let buf = RawVec::with_capacity(len);
+        unsafe {
+            ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len);
+            buf.into_box(slice.len()).assume_init()
+        }
+    }
+}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "box_from_slice", since = "1.17.0")]
-impl<T: Copy> From<&[T]> for Box<[T]> {
+impl<T: Clone> From<&[T]> for Box<[T]> {
     /// Converts a `&[T]` into a `Box<[T]>`
     ///
     /// This conversion allocates on the heap
@@ -1498,19 +1502,15 @@ impl<T: Copy> From<&[T]> for Box<[T]> {
     ///
     /// println!("{boxed_slice:?}");
     /// ```
+    #[inline]