It's used to work around an objtool issue since commit abb2a5572264
("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference"), but
it's then passed to bindgen and cause an error because Clang does not
have this option.

Fixes: abb2a5572264 ("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference")
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Mingcong Bai <jeffbai@aosc.io>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

The `rustdoc` modifiers bug [1] was fixed in Rust 1.90.0 [2], for which
we added a workaround in commit abbf9a449441 ("rust: workaround `rustdoc`
target modifiers bug").

However, `rustdoc`'s doctest generation still has a similar issue [3],
being fixed at [4], which does not affect us because we apply the
workaround to both, and now, starting with Rust 1.91.0 (released
2025-10-30), `-Zsanitizer` is a target modifier too [5], which means we
fail with:

      RUSTDOC TK rust/kernel/lib.rs
    error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `kernel`
     --> rust/kernel/lib.rs:3:1
      |
    3 | //! The `kernel` crate.
      | ^
      |
      = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
      = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core`
      = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core`
      = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error

A simple way around is to add the sanitizer to the list in the existing
workaround (especially if we had not started to pass the sanitizer
flags in the previous commit, since in that case that would not be
necessary). However, that still applies the workaround in more cases
than necessary.

Instead, only modify the doctests flags to ignore the check for
sanitizers, so that it is more local (and thus the compiler keeps checking
it for us in the normal `rustdoc` calls). Since the previous commit
already treated the `rustdoc` calls as kernel objects, this should allow
us in the future to easily remove this workaround when the time comes.

By the way, the `-Cunsafe-allow-abi-mismatch` flag overwrites previous
ones rather than appending, so it needs to be all done in the same flag.
Moreover, unknown modifiers are rejected, and thus we have to gate based
on the version too.

Finally, `-Zsanitizer-cfi-normalize-integers` is not affected (in Rust
1.91.0), so it is not needed in the workaround for the moment.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust/issues/144521 [1]
Link: https://github.com/rust-lang/rust/pull/144523 [2]
Link: https://github.com/rust-lang/rust/issues/146465 [3]
Link: https://github.com/rust-lang/rust/pull/148068 [4]
Link: https://github.com/rust-lang/rust/pull/138736 [5]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
Link: https://patch.msgid.link/20251102212853.1505384-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Even if normally `build_error` isn't a kernel object, it should still
be treated as such so that we pass the same flags. Similarly, `rustdoc`
targets are never kernel objects, but we need to treat them as such.

Otherwise, starting with Rust 1.91.0 (released 2025-10-30), `rustc`
will complain about missing sanitizer flags since `-Zsanitizer` is a
target modifier too [1]:

    error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `build_error`
     --> rust/build_error.rs:3:1
      |
    3 | //! Build-time error.
      | ^
      |
      = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
      = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core`
      = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core`
      = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error

Thus explicitly mark them as kernel objects.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust/pull/138736 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
Link: https://patch.msgid.link/20251102212853.1505384-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This allows `bindings` and `uapi` to implement `Zeroable` and use other
items from pin-init.

Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/291565-Help/topic/Zeroable.20trait.20for.20C.20structs/near/510264158
Signed-off-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

`srctree/` links may point to nonexistent files, e.g. due to renames
that missed to update the files or simply because of typos.

Since they can be easily checked for validity, do so and print a warning
in the file does not exist.

This found the following cases already in-tree:

    warning: srctree/ link to include/linux/blk_mq.h does not exist
    warning: srctree/ link to include/linux/drm/drm_gem.h does not exist
    warning: srctree/ link to include/linux/drm/drm_drv.h does not exist
    warning: srctree/ link to include/linux/drm/drm_ioctl.h does not exist
    warning: srctree/ link to include/linux/drm/drm_file.h does not exist
    warning: srctree/ link to include/linux/drm/drm_device.h does not exist

Inspired-by: Onur Özkan <work@onurozkan.dev>
Link: https://lore.kernel.org/rust-for-linux/CANiq72=xCYA7z7_rxpzzKkkhJs6m7L_xEaLMuArVn3ZAcyeHdA@mail.gmail.com/
Reviewed-by: Onur Özkan <work@onurozkan.dev>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Tested-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Pull alloc and DMA updates from Danilo Krummrich:

  Allocator:
   - Provide information about the minimum alignment guarantees of
     'Kmalloc', 'Vmalloc' and 'KVmalloc'.
   - Take minimum alignment guarantees of allocators for
     'ForeignOwnable' into account.
   - Remove the 'allocator_test' incl. 'Cmalloc'.

  Box:
   - Implement 'Box::pin_slice()', which constructs a pinned slice of
     elements.

  Vec:
   - Simplify KUnit test module name to 'rust_kvec'.
   - Add doc-test for 'Vec::as_slice()'.
   - Constify various methods.

  DMA:
   - Update 'ARef' and 'AlwaysRefCounted' imports.

  MISC:
   - Remove support for unused host '#[test]'s.
   - Constify 'ArrayLayout::new_unchecked()'.

* tag 'alloc-next-v6.18-2025-09-04' of https://github.com/Rust-for-Linux/linux:
  rust: alloc: remove `allocator_test`
  rust: kernel: remove support for unused host `#[test]`s
  rust: alloc: implement Box::pin_slice()
  rust: alloc: add ARCH_KMALLOC_MINALIGN to bindgen blocklist
  rust: dma: Update ARef and AlwaysRefCounted imports from sync::aref
  rust: alloc: take the allocator into account for FOREIGN_ALIGN
  rust: alloc: specify the minimum alignment of each allocator
  rust: make `kvec::Vec` functions `const fn`
  rust: make `ArrayLayout::new_unchecked` a `const fn`
  rust: alloc: kvec: simplify KUnit test module name to "rust_kvec"
  rust: alloc: kvec: add doc example for as_slice method

Since commit 028df914e546 ("rust: str: convert `rusttest` tests into
KUnit"), we do not have anymore host `#[test]`s that run in the host.

Moreover, we do not plan to add any new ones -- tests should generally
run within KUnit, since there they are built the same way the kernel
does. While we may want to have some way to define tests that can also
be run outside the kernel, we still want to test within the kernel too
[1], and thus would likely use a custom syntax anyway to define them.

Thus simplify the `rusttest` target by removing support for host
`#[test]`s for the `kernel` crate.

This still maintains the support for the `macros` crate, even though we
do not have any such tests there.

Link: https://lore.kernel.org/rust-for-linux/CABVgOS=AKHSfifp0S68K3jgNZAkALBr=7iFb=niryG5WDxjSrg@mail.gmail.com/ [1]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20250726180750.2735836-1-ojeda@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

`rustdoc` can get confused when generating documentation into a folder
that contains generated files from other `rustdoc` versions.

For instance, running something like:

    rustup default 1.78.0
    make LLVM=1 rustdoc
    rustup default 1.88.0
    make LLVM=1 rustdoc

may generate errors like:

    error: couldn't generate documentation: invalid template: last line expected to start with a comment
      |
      = note: failed to create or modify "./Documentation/output/rust/rustdoc/src-files.js"

Thus just always clean the output folder before generating the
documentation -- we are anyway regenerating it every time the `rustdoc`
target gets called, at least for the time being.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Reported-by: Daniel Almeida <daniel.almeida@collabora.com>
Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/288089/topic/x/near/527201113
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Link: https://lore.kernel.org/r/20250726133435.2460085-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains
about a target modifier mismatch in configurations where `-Zfixed-x18`
is passed:

    error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out`
      |
      = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
      = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core`
      = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core`
      = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error

The reason is that `rustdoc` was not passing the target modifiers when
configuring the session options, and thus it would report a mismatch
that did not exist as soon as a target modifier is used in a dependency.

We did not notice it in the kernel until now because `-Zfixed-x18` has
been a target modifier only since 1.88.0 (and it is the only one we use
so far).

The issue has been reported upstream [1] and a fix has been submitted
[2], including a test similar to the kernel case.

  [ This is now fixed upstream (thanks Guillaume for the quick review),
    so it will be fixed in Rust 1.90.0 (expected 2025-09-18).

      - Miguel ]

Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18`
to workaround the issue on our side.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Reported-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Closes: https://lore.kernel.org/rust-for-linux/36cdc798-524f-4910-8b77-d7b9fac08d77@oss.qualcomm.com/
Link: https://github.com/rust-lang/rust/issues/144521 [1]
Link: https://github.com/rust-lang/rust/pull/144523 [2]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250727092317.2930617-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Enable a set of Clippy lints: 'ptr_as_ptr', 'ptr_cast_constness',
     'as_ptr_cast_mut', 'as_underscore', 'cast_lossless' and
     'ref_as_ptr'

     These are intended to avoid type casts with the 'as' operator,
     which are quite powerful, into restricted variants that are less
     powerful and thus should help to avoid mistakes

   - Remove the 'author' key now that most instances were moved to the
     plural one in the previous cycle

  'kernel' crate:

   - New 'bug' module: add 'warn_on!' macro which reuses the existing
     'BUG'/'WARN' infrastructure, i.e. it respects the usual sysctls and
     kernel parameters:

         warn_on!(value == 42);

     To avoid duplicating the assembly code, the same strategy is
     followed as for the static branch code in order to share the
     assembly between both C and Rust

     This required a few rearrangements on C arch headers -- the
     existing C macros should still generate the same outputs, thus no
     functional change expected there

   - 'workqueue' module: add delayed work items, including a
     'DelayedWork' struct, a 'impl_has_delayed_work!' macro and an
     'enqueue_delayed' method, e.g.:

         /// Enqueue the struct for execution on the system workqueue,
         /// where its value will be printed 42 jiffies later.
         fn print_later(value: Arc<MyStruct>) {
             let _ = workqueue::system().enqueue_delayed(value, 42);
         }

   - New 'bits' module: add support for 'bit' and 'genmask' functions,
     with runtime- and compile-time variants, e.g.:

         static_assert!(0b00010000 == bit_u8(4));
         static_assert!(0b00011110 == genmask_u8(1..=4));

         assert!(checked_bit_u32(u32::BITS).is_none());

   - 'uaccess' module: add 'UserSliceReader::strcpy_into_buf', which
     reads NUL-terminated strings from userspace into a '&CStr'

     Introduce 'UserPtr' newtype, similar in purpose to '__user' in C,
     to minimize mistakes handling userspace pointers, including mixing
     them up with integers and leaking them via the 'Debug' trait. Add
     it to the prelude, too

   - Start preparations for the replacement of our custom 'CStr' type
     with the analogous type in the 'core' standard library. This will
     take place across several cycles to make it easier. For this one,
     it includes a new 'fmt' module, using upstream method names and
     some other cleanups

     Replace 'fmt!' with a re-export, which helps Clippy lint properly,
     and clean up the found 'uninlined-format-args' instances

   - 'dma' module:

      - Clarify wording and be consistent in 'coherent' nomenclature

      - Convert the 'read!()' and 'write!()' macros to return a 'Result'

      - Add 'as_slice()', 'write()' methods in 'CoherentAllocation'

      - Expose 'count()' and 'size()' in 'CoherentAllocation' and add
        the corresponding type invariants

      - Implement 'CoherentAllocation::dma_handle_with_offset()'

   - 'time' module:

      - Make 'Instant' generic over clock source. This allows the
        compiler to assert that arithmetic expressions involving the
        'Instant' use 'Instants' based on the same clock source

      - Make 'HrTimer' generic over the timer mode. 'HrTimer' timers
        take a 'Duration' or an 'Instant' when setting the expiry time,
        depending on the timer mode. With this change, the compiler can
        check the type matches the timer mode

      - Add an abstraction for 'fsleep'. 'fsleep' is a flexible sleep
        function that will select an appropriate sleep method depending
        on the requested sleep time

      - Avoid 64-bit divisions on 32-bit hardware when calculating
        timestamps

      - Seal the 'HrTimerMode' trait. This prevents users of the
        'HrTimerMode' from implementing the trait on their own types

      - Pass the correct timer mode ID to 'hrtimer_start_range_ns()'

   - 'list' module: remove 'OFFSET' constants, allowing to remove
     pointer arithmetic; now 'impl_list_item!' invokes
     'impl_has_list_links!' or 'impl_has_list_links_self_ptr!'. Other
     simplifications too

   - 'types' module: remove 'ForeignOwnable::PointedTo' in favor of a
     constant, which avoids exposing the type of the opaque pointer, and
     require 'into_foreign' to return non-null

     Remove the 'Either<L, R>' type as well. It is unused, and we want
     to encourage the use of custom enums for concrete use cases

   - 'sync' module: implement 'Borrow' and 'BorrowMut' for 'Arc' types
     to allow them to be used in generic APIs

   - 'alloc' module: implement 'Borrow' and 'BorrowMut' for 'Box<T, A>';
     and 'Borrow', 'BorrowMut' and 'Default' for 'Vec<T, A>'

   - 'Opaque' type: add 'cast_from' method to perform a restricted cast
     that cannot change the inner type and use it in callers of
     'container_of!'. Rename 'raw_get' to 'cast_into' to match it

   - 'rbtree' module: add 'is_empty' method

   - 'sync' module: new 'aref' submodule to hold 'AlwaysRefCounted' and
     'ARef', which are moved from the too general 'types' module which
     we want to reduce or eventually remove. Also fix a safety comment
     in 'static_lock_class'

  'pin-init' crate:

   - Add 'impl<T, E> [Pin]Init<T, E> for Result<T, E>', so results are
     now (pin-)initializers

   - Add 'Zeroable::init_zeroed()' that delegates to 'init_zeroed()'

   - New 'zeroed()', a safe version of 'mem::zeroed()' and also provide
     it via 'Zeroable::zeroed()'

   - Implement 'Zeroable' for 'Option<&T>', 'Option<&mut T>' and for
     'Option<[unsafe] [extern "abi"] fn(...args...) -> ret>' for
     '"Rust"' and '"C"' ABIs and up to 20 arguments

   - Changed blanket impls of 'Init' and 'PinInit' from 'impl<T, E>
     [Pin]Init<T, E> for T' to 'impl<T> [Pin]Init<T> for T'

   - Renamed 'zeroed()' to 'init_zeroed()'

   - Upstream dev news: improve CI more to deny warnings, use
     '--all-targets'. Check the synchronization status of the two
     '-next' branches in upstream and the kernel

  MAINTAINERS:

   - Add Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki and Lorenzo
     Stoakes as reviewers (thanks everyone)

  And a few other cleanups and improvements"

* tag 'rust-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (76 commits)
  rust: Add warn_on macro
  arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  rust: kernel: move ARef and AlwaysRefCounted to sync::aref
  rust: sync: fix safety comment for `static_lock_class`
  rust: types: remove `Either<L, R>`
  rust: kernel: use `core::ffi::CStr` method names
  rust: str: add `CStr` methods matching `core::ffi::CStr`
  rust: str: remove unnecessary qualification
  rust: use `kernel::{fmt,prelude::fmt!}`
  rust: kernel: add `fmt` module
  rust: kernel: remove `fmt!`, fix clippy::uninlined-format-args
  scripts: rust: emit path candidates in panic message
  scripts: rust: replace length checks with match
  rust: list: remove nonexistent generic parameter in link
  rust: bits: add support for bits/genmask macros
  rust: list: remove OFFSET constants
  rust: list: add `impl_list_item!` examples
  rust: list: use fully qualified path
  ...