<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/scripts/Makefile.build, branch v7.1-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'driver-core-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core</title>
<updated>2026-04-14T02:03:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-04-14T02:03:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4793dae01f47754e288cdbb3a22581cac2317f2b'/>
<id>4793dae01f47754e288cdbb3a22581cac2317f2b</id>
<content type='text'>
Pull driver core updates from Danilo Krummrich:
 "debugfs:
   - Fix NULL pointer dereference in debugfs_create_str()
   - Fix misplaced EXPORT_SYMBOL_GPL for debugfs_create_str()
   - Fix soundwire debugfs NULL pointer dereference from uninitialized
     firmware_file

  device property:
   - Make fwnode flags modifications thread safe; widen the field to
     unsigned long and use set_bit() / clear_bit() based accessors
   - Document how to check for the property presence

  devres:
   - Separate struct devres_node from its "subclasses" (struct devres,
     struct devres_group); give struct devres_node its own release and
     free callbacks for per-type dispatch
   - Introduce struct devres_action for devres actions, avoiding the
     ARCH_DMA_MINALIGN alignment overhead of struct devres
   - Export struct devres_node and its init/add/remove/dbginfo
     primitives for use by Rust Devres&lt;T&gt;
   - Fix missing node debug info in devm_krealloc()
   - Use guard(spinlock_irqsave) where applicable; consolidate unlock
     paths in devres_release_group()

  driver_override:
   - Convert PCI, WMI, vdpa, s390/cio, s390/ap, and fsl-mc to the
     generic driver_override infrastructure, replacing per-bus
     driver_override strings, sysfs attributes, and match logic; fixes a
     potential UAF from unsynchronized access to driver_override in bus
     match() callbacks
   - Simplify __device_set_driver_override() logic

  kernfs:
   - Send IN_DELETE_SELF and IN_IGNORED inotify events on kernfs file
     and directory removal
   - Add corresponding selftests for memcg

  platform:
   - Allow attaching software nodes when creating platform devices via a
     new 'swnode' field in struct platform_device_info
   - Add kerneldoc for struct platform_device_info

  software node:
   - Move software node initialization from postcore_initcall() to
     driver_init(), making it available early in the boot process
   - Move kernel_kobj initialization (ksysfs_init) earlier to support
     the above
   - Remove software_node_exit(); dead code in a built-in unit

  SoC:
   - Introduce of_machine_read_compatible() and of_machine_read_model()
     OF helpers and export soc_attr_read_machine() to replace direct
     accesses to of_root from SoC drivers; also enables
     CONFIG_COMPILE_TEST coverage for these drivers

  sysfs:
   - Constify attribute group array pointers to
     'const struct attribute_group *const *' in sysfs functions,
     device_add_groups() / device_remove_groups(), and struct class

  Rust:
   - Devres:
      - Embed struct devres_node directly in Devres&lt;T&gt; instead of going
        through devm_add_action(), avoiding the extra allocation and the
        unnecessary ARCH_DMA_MINALIGN alignment

   - I/O:
      - Turn IoCapable from a marker trait into a functional trait
        carrying the raw I/O accessor implementation (io_read /
        io_write), providing working defaults for the per-type Io
        methods
      - Add RelaxedMmio wrapper type, making relaxed accessors usable in
        code generic over the Io trait
      - Remove overloaded per-type Io methods and per-backend macros
        from Mmio and PCI ConfigSpace

   - I/O (Register):
      - Add IoLoc trait and generic read/write/update methods to the Io
        trait, making I/O operations parameterizable by typed locations
      - Add register! macro for defining hardware register types with
        typed bitfield accessors backed by Bounded values; supports
        direct, relative, and array register addressing
      - Add write_reg() / try_write_reg() and LocatedRegister trait
      - Update PCI sample driver to demonstrate the register! macro

         Example:

         ```
             register! {
                 /// UART control register.
                 CTRL(u32) @ 0x18 {
                     /// Receiver enable.
                     19:19   rx_enable =&gt; bool;
                     /// Parity configuration.
                     14:13   parity ?=&gt; Parity;
                 }

                 /// FIFO watermark and counter register.
                 WATER(u32) @ 0x2c {
                     /// Number of datawords in the receive FIFO.
                     26:24   rx_count;
                     /// RX interrupt threshold.
                     17:16   rx_water;
                 }
             }

             impl WATER {
                 fn rx_above_watermark(&amp;self) -&gt; bool {
                     self.rx_count() &gt; self.rx_water()
                 }
             }

             fn init(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;) {
                 let water = WATER::zeroed()
                     .with_const_rx_water::&lt;1&gt;(); // &gt; 3 would not compile
                 bar.write_reg(water);

                 let ctrl = CTRL::zeroed()
                     .with_parity(Parity::Even)
                     .with_rx_enable(true);
                 bar.write_reg(ctrl);
             }

             fn handle_rx(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;) {
                 if bar.read(WATER).rx_above_watermark() {
                     // drain the FIFO
                 }
             }

             fn set_parity(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;, parity: Parity) {
                 bar.update(CTRL, |r| r.with_parity(parity));
             }
         ```

   - IRQ:
      - Move 'static bounds from where clauses to trait declarations for
        IRQ handler traits

   - Misc:
      - Enable the generic_arg_infer Rust feature
      - Extend Bounded with shift operations, single-bit bool
        conversion, and const get()

  Misc:
   - Make deferred_probe_timeout default a Kconfig option
   - Drop auxiliary_dev_pm_ops; the PM core falls back to driver PM
     callbacks when no bus type PM ops are set
   - Add conditional guard support for device_lock()
   - Add ksysfs.c to the DRIVER CORE MAINTAINERS entry
   - Fix kernel-doc warnings in base.h
   - Fix stale reference to memory_block_add_nid() in documentation"

* tag 'driver-core-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (67 commits)
  bus: fsl-mc: use generic driver_override infrastructure
  s390/ap: use generic driver_override infrastructure
  s390/cio: use generic driver_override infrastructure
  vdpa: use generic driver_override infrastructure
  platform/wmi: use generic driver_override infrastructure
  PCI: use generic driver_override infrastructure
  driver core: make software nodes available earlier
  software node: remove software_node_exit()
  kernel: ksysfs: initialize kernel_kobj earlier
  MAINTAINERS: add ksysfs.c to the DRIVER CORE entry
  drivers/base/memory: fix stale reference to memory_block_add_nid()
  device property: Document how to check for the property presence
  soundwire: debugfs: initialize firmware_file to empty string
  debugfs: fix placement of EXPORT_SYMBOL_GPL for debugfs_create_str()
  debugfs: check for NULL pointer in debugfs_create_str()
  driver core: Make deferred_probe_timeout default a Kconfig option
  driver core: simplify __device_set_driver_override() clearing logic
  driver core: auxiliary bus: Drop auxiliary_dev_pm_ops
  device property: Make modifications of fwnode "flags" thread safe
  rust: devres: embed struct devres_node directly
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull driver core updates from Danilo Krummrich:
 "debugfs:
   - Fix NULL pointer dereference in debugfs_create_str()
   - Fix misplaced EXPORT_SYMBOL_GPL for debugfs_create_str()
   - Fix soundwire debugfs NULL pointer dereference from uninitialized
     firmware_file

  device property:
   - Make fwnode flags modifications thread safe; widen the field to
     unsigned long and use set_bit() / clear_bit() based accessors
   - Document how to check for the property presence

  devres:
   - Separate struct devres_node from its "subclasses" (struct devres,
     struct devres_group); give struct devres_node its own release and
     free callbacks for per-type dispatch
   - Introduce struct devres_action for devres actions, avoiding the
     ARCH_DMA_MINALIGN alignment overhead of struct devres
   - Export struct devres_node and its init/add/remove/dbginfo
     primitives for use by Rust Devres&lt;T&gt;
   - Fix missing node debug info in devm_krealloc()
   - Use guard(spinlock_irqsave) where applicable; consolidate unlock
     paths in devres_release_group()

  driver_override:
   - Convert PCI, WMI, vdpa, s390/cio, s390/ap, and fsl-mc to the
     generic driver_override infrastructure, replacing per-bus
     driver_override strings, sysfs attributes, and match logic; fixes a
     potential UAF from unsynchronized access to driver_override in bus
     match() callbacks
   - Simplify __device_set_driver_override() logic

  kernfs:
   - Send IN_DELETE_SELF and IN_IGNORED inotify events on kernfs file
     and directory removal
   - Add corresponding selftests for memcg

  platform:
   - Allow attaching software nodes when creating platform devices via a
     new 'swnode' field in struct platform_device_info
   - Add kerneldoc for struct platform_device_info

  software node:
   - Move software node initialization from postcore_initcall() to
     driver_init(), making it available early in the boot process
   - Move kernel_kobj initialization (ksysfs_init) earlier to support
     the above
   - Remove software_node_exit(); dead code in a built-in unit

  SoC:
   - Introduce of_machine_read_compatible() and of_machine_read_model()
     OF helpers and export soc_attr_read_machine() to replace direct
     accesses to of_root from SoC drivers; also enables
     CONFIG_COMPILE_TEST coverage for these drivers

  sysfs:
   - Constify attribute group array pointers to
     'const struct attribute_group *const *' in sysfs functions,
     device_add_groups() / device_remove_groups(), and struct class

  Rust:
   - Devres:
      - Embed struct devres_node directly in Devres&lt;T&gt; instead of going
        through devm_add_action(), avoiding the extra allocation and the
        unnecessary ARCH_DMA_MINALIGN alignment

   - I/O:
      - Turn IoCapable from a marker trait into a functional trait
        carrying the raw I/O accessor implementation (io_read /
        io_write), providing working defaults for the per-type Io
        methods
      - Add RelaxedMmio wrapper type, making relaxed accessors usable in
        code generic over the Io trait
      - Remove overloaded per-type Io methods and per-backend macros
        from Mmio and PCI ConfigSpace

   - I/O (Register):
      - Add IoLoc trait and generic read/write/update methods to the Io
        trait, making I/O operations parameterizable by typed locations
      - Add register! macro for defining hardware register types with
        typed bitfield accessors backed by Bounded values; supports
        direct, relative, and array register addressing
      - Add write_reg() / try_write_reg() and LocatedRegister trait
      - Update PCI sample driver to demonstrate the register! macro

         Example:

         ```
             register! {
                 /// UART control register.
                 CTRL(u32) @ 0x18 {
                     /// Receiver enable.
                     19:19   rx_enable =&gt; bool;
                     /// Parity configuration.
                     14:13   parity ?=&gt; Parity;
                 }

                 /// FIFO watermark and counter register.
                 WATER(u32) @ 0x2c {
                     /// Number of datawords in the receive FIFO.
                     26:24   rx_count;
                     /// RX interrupt threshold.
                     17:16   rx_water;
                 }
             }

             impl WATER {
                 fn rx_above_watermark(&amp;self) -&gt; bool {
                     self.rx_count() &gt; self.rx_water()
                 }
             }

             fn init(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;) {
                 let water = WATER::zeroed()
                     .with_const_rx_water::&lt;1&gt;(); // &gt; 3 would not compile
                 bar.write_reg(water);

                 let ctrl = CTRL::zeroed()
                     .with_parity(Parity::Even)
                     .with_rx_enable(true);
                 bar.write_reg(ctrl);
             }

             fn handle_rx(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;) {
                 if bar.read(WATER).rx_above_watermark() {
                     // drain the FIFO
                 }
             }

             fn set_parity(bar: &amp;pci::Bar&lt;BAR0_SIZE&gt;, parity: Parity) {
                 bar.update(CTRL, |r| r.with_parity(parity));
             }
         ```

   - IRQ:
      - Move 'static bounds from where clauses to trait declarations for
        IRQ handler traits

   - Misc:
      - Enable the generic_arg_infer Rust feature
      - Extend Bounded with shift operations, single-bit bool
        conversion, and const get()

  Misc:
   - Make deferred_probe_timeout default a Kconfig option
   - Drop auxiliary_dev_pm_ops; the PM core falls back to driver PM
     callbacks when no bus type PM ops are set
   - Add conditional guard support for device_lock()
   - Add ksysfs.c to the DRIVER CORE MAINTAINERS entry
   - Fix kernel-doc warnings in base.h
   - Fix stale reference to memory_block_add_nid() in documentation"

* tag 'driver-core-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core: (67 commits)
  bus: fsl-mc: use generic driver_override infrastructure
  s390/ap: use generic driver_override infrastructure
  s390/cio: use generic driver_override infrastructure
  vdpa: use generic driver_override infrastructure
  platform/wmi: use generic driver_override infrastructure
  PCI: use generic driver_override infrastructure
  driver core: make software nodes available earlier
  software node: remove software_node_exit()
  kernel: ksysfs: initialize kernel_kobj earlier
  MAINTAINERS: add ksysfs.c to the DRIVER CORE entry
  drivers/base/memory: fix stale reference to memory_block_add_nid()
  device property: Document how to check for the property presence
  soundwire: debugfs: initialize firmware_file to empty string
  debugfs: fix placement of EXPORT_SYMBOL_GPL for debugfs_create_str()
  debugfs: check for NULL pointer in debugfs_create_str()
  driver core: Make deferred_probe_timeout default a Kconfig option
  driver core: simplify __device_set_driver_override() clearing logic
  driver core: auxiliary bus: Drop auxiliary_dev_pm_ops
  device property: Make modifications of fwnode "flags" thread safe
  rust: devres: embed struct devres_node directly
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: kbuild: remove `feature(...)`s that are now stable</title>
<updated>2026-04-07T08:00:24+00:00</updated>
<author>
<name>Miguel Ojeda</name>
<email>ojeda@kernel.org</email>
</author>
<published>2026-04-05T23:52:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d1aa40daa777c74439eebf8aed17392e23685768'/>
<id>d1aa40daa777c74439eebf8aed17392e23685768</id>
<content type='text'>
Now that the Rust minimum version is 1.85.0, there is no need to enable
certain features that are stable.

Thus clean them up.

Reviewed-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260405235309.418950-13-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that the Rust minimum version is 1.85.0, there is no need to enable
certain features that are stable.

Thus clean them up.

Reviewed-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260405235309.418950-13-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: support overriding crate_name</title>
<updated>2026-04-03T09:57:35+00:00</updated>
<author>
<name>Alice Ryhl</name>
<email>aliceryhl@google.com</email>
</author>
<published>2026-04-02T10:55:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7e9535ebd05d7e8de155164b7c97a370d4646e06'/>
<id>7e9535ebd05d7e8de155164b7c97a370d4646e06</id>
<content type='text'>
Currently you cannot filter out the crate-name argument
RUSTFLAGS_REMOVE_stem.o because the Rust filter-out invocation does not
include that particular argument. Since --crate-name is an argument that
can't be passed multiple times, this means that it's currently not
possible to override the crate name. Thus, remove the --crate-name
argument for drivers. This allows them to override the crate name using
the #![crate_name] annotation.

This affects symbol names, but has no effect on the filenames of object
files and other things generated by the build, as we always use --emit
with a fixed output filename.

The --crate-name argument is kept for the crates under rust/ for
simplicity and to avoid changing many of them by adding #![crate_name].

The rust analyzer script is updated to use rustc to obtain the crate
name of the driver crates, which picks up the right name whether it is
configured via #![crate_name] or not. For readability, the logic to
invoke 'rustc' is extracted to its own function.

Note that the crate name in the python script is not actually that
important - the only place where the name actually affects anything is
in the 'deps' array which specifies an index and name for each
dependency, and determines what that dependency is called in *this*
crate. (The same crate may be called different things in each
dependency.) Since driver crates are leaf crates, this doesn't apply and
the rustc invocation only affects the 'display_name' parameter.

Acked-by: Gary Guo &lt;gary@garyguo.net&gt;
Signed-off-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Jesung Yang &lt;y.jems.n@gmail.com&gt;
Acked-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Link: https://patch.msgid.link/20260402-binder-crate-name-v4-1-ec3919b87909@google.com
[ Applied Python type hints. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently you cannot filter out the crate-name argument
RUSTFLAGS_REMOVE_stem.o because the Rust filter-out invocation does not
include that particular argument. Since --crate-name is an argument that
can't be passed multiple times, this means that it's currently not
possible to override the crate name. Thus, remove the --crate-name
argument for drivers. This allows them to override the crate name using
the #![crate_name] annotation.

This affects symbol names, but has no effect on the filenames of object
files and other things generated by the build, as we always use --emit
with a fixed output filename.

The --crate-name argument is kept for the crates under rust/ for
simplicity and to avoid changing many of them by adding #![crate_name].

The rust analyzer script is updated to use rustc to obtain the crate
name of the driver crates, which picks up the right name whether it is
configured via #![crate_name] or not. For readability, the logic to
invoke 'rustc' is extracted to its own function.

Note that the crate name in the python script is not actually that
important - the only place where the name actually affects anything is
in the 'deps' array which specifies an index and name for each
dependency, and determines what that dependency is called in *this*
crate. (The same crate may be called different things in each
dependency.) Since driver crates are leaf crates, this doesn't apply and
the rustc invocation only affects the 'display_name' parameter.

Acked-by: Gary Guo &lt;gary@garyguo.net&gt;
Signed-off-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Jesung Yang &lt;y.jems.n@gmail.com&gt;
Acked-by: Tamir Duberstein &lt;tamird@kernel.org&gt;
Link: https://patch.msgid.link/20260402-binder-crate-name-v4-1-ec3919b87909@google.com
[ Applied Python type hints. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kbuild: rust: provide an option to inline C helpers into Rust</title>
<updated>2026-03-30T00:03:52+00:00</updated>
<author>
<name>Gary Guo</name>
<email>gary@garyguo.net</email>
</author>
<published>2026-02-03T11:34:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3a2486cc1da5cf637fe5da4540929d67c4540022'/>
<id>3a2486cc1da5cf637fe5da4540929d67c4540022</id>
<content type='text'>
A new experimental Kconfig option, `RUST_INLINE_HELPERS` is added to
allow C helpers (which were created to allow Rust to call into
inline/macro C functions without having to re-implement the logic in
Rust) to be inlined into Rust crates without performing global LTO.

If the option is enabled, the following is performed:
* For helpers, instead of compiling them to an object file to be linked
  into vmlinux, they're compiled to LLVM IR bitcode. Two versions are
  generated: one for built-in code (`helpers.bc`) and one for modules
  (`helpers_module.bc`, with -DMODULE defined). This ensures that C
  macros/inlines that behave differently for modules (e.g. static calls)
  function correctly when inlined.
* When a Rust crate or object is compiled, instead of generating an
  object file, LLVM bitcode is generated.
* llvm-link is invoked with --internalize to combine the helper bitcode
  with the crate bitcode. This step is similar to LTO, but this is much
  faster since it only needs to inline the helpers.
* clang is invoked to turn the combined bitcode into a final object file.
* Since clang may produce LLVM bitcode when LTO is enabled, and objtool
  requires ELF input, $(cmd_ld_single) is invoked to ensure the object
  is converted to ELF before objtool runs.

The --internalize flag tells llvm-link to treat all symbols in
helpers.bc using `internal` linkage [1]. This matches the behavior of
`clang` on `static inline` functions, and avoids exporting the symbol
from the object file.

To ensure that RUST_INLINE_HELPERS is not incompatible with BTF, we pass
the -g0 flag when building helpers. See commit 5daa0c35a1f0 ("rust:
Disallow BTF generation with Rust + LTO") for details.

We have an intended triple mismatch of `aarch64-unknown-none` vs
`aarch64-unknown-linux-gnu`, so we pass --suppress-warnings to llvm-link
to suppress it.

I considered adding some sort of check that KBUILD_MODNAME is not
present in helpers_module.bc, but this is actually not so easy to carry
out because .bc files store strings in a weird binary format, so you
cannot just grep it for a string to check whether it ended up using
KBUILD_MODNAME anywhere.

[ Andreas writes:

    For the rnull driver, enabling helper inlining with this patch
    gives an average speedup of 2% over the set of 120 workloads that
    we publish on [2].

    Link: https://rust-for-linux.com/null-block-driver [2]

  This series also uncovered a pre-existing UB instance thanks to an
  `objtool` warning which I noticed while testing the series (details
  in the mailing list).

      - Miguel ]

Link: https://github.com/llvm/llvm-project/pull/170397 [1]
Co-developed-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Signed-off-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Co-developed-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Signed-off-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Co-developed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Signed-off-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Tested-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Tested-by: Andreas Hindborg &lt;a.hindborg@kernel.org&gt;
Reviewed-by: Andreas Hindborg &lt;a.hindborg@kernel.org&gt;
Link: https://patch.msgid.link/20260203-inline-helpers-v2-3-beb8547a03c9@google.com
[ Some changes, apart from the rebase:

  - Added "(EXPERIMENTAL)" to Kconfig as the commit mentions.

  - Added `depends on ARM64 || X86_64` and `!UML` for now, since this is
    experimental, other architectures may require other changes (e.g.
    the issues I mentioned in the mailing list for ARM and UML) and they
    are not really tested so far. So let arch maintainers pick this up
    if they think it is worth it.

  - Gated the `cmd_ld_single` step also into the new mode, which also
    means that any possible future `objcopy` step is done after the
    translation, as expected.

  - Added `.gitignore` for `.bc` with exception for existing script.

  - Added `part-of-*` for helpers bitcode files as discussed, and
    dropped `$(if $(filter %_module.bc,$@),-DMODULE)` since `-DMODULE`
    is already there (would be duplicated otherwise).

  - Moved `LLVM_LINK` to keep binutils list alphabetized.

  - Fixed typo in title.

  - Dropped second `cmd_ld_single` commit message paragraph.

      - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A new experimental Kconfig option, `RUST_INLINE_HELPERS` is added to
allow C helpers (which were created to allow Rust to call into
inline/macro C functions without having to re-implement the logic in
Rust) to be inlined into Rust crates without performing global LTO.

If the option is enabled, the following is performed:
* For helpers, instead of compiling them to an object file to be linked
  into vmlinux, they're compiled to LLVM IR bitcode. Two versions are
  generated: one for built-in code (`helpers.bc`) and one for modules
  (`helpers_module.bc`, with -DMODULE defined). This ensures that C
  macros/inlines that behave differently for modules (e.g. static calls)
  function correctly when inlined.
* When a Rust crate or object is compiled, instead of generating an
  object file, LLVM bitcode is generated.
* llvm-link is invoked with --internalize to combine the helper bitcode
  with the crate bitcode. This step is similar to LTO, but this is much
  faster since it only needs to inline the helpers.
* clang is invoked to turn the combined bitcode into a final object file.
* Since clang may produce LLVM bitcode when LTO is enabled, and objtool
  requires ELF input, $(cmd_ld_single) is invoked to ensure the object
  is converted to ELF before objtool runs.

The --internalize flag tells llvm-link to treat all symbols in
helpers.bc using `internal` linkage [1]. This matches the behavior of
`clang` on `static inline` functions, and avoids exporting the symbol
from the object file.

To ensure that RUST_INLINE_HELPERS is not incompatible with BTF, we pass
the -g0 flag when building helpers. See commit 5daa0c35a1f0 ("rust:
Disallow BTF generation with Rust + LTO") for details.

We have an intended triple mismatch of `aarch64-unknown-none` vs
`aarch64-unknown-linux-gnu`, so we pass --suppress-warnings to llvm-link
to suppress it.

I considered adding some sort of check that KBUILD_MODNAME is not
present in helpers_module.bc, but this is actually not so easy to carry
out because .bc files store strings in a weird binary format, so you
cannot just grep it for a string to check whether it ended up using
KBUILD_MODNAME anywhere.

[ Andreas writes:

    For the rnull driver, enabling helper inlining with this patch
    gives an average speedup of 2% over the set of 120 workloads that
    we publish on [2].

    Link: https://rust-for-linux.com/null-block-driver [2]

  This series also uncovered a pre-existing UB instance thanks to an
  `objtool` warning which I noticed while testing the series (details
  in the mailing list).

      - Miguel ]

Link: https://github.com/llvm/llvm-project/pull/170397 [1]
Co-developed-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Signed-off-by: Boqun Feng &lt;boqun.feng@gmail.com&gt;
Co-developed-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Signed-off-by: Matthew Maurer &lt;mmaurer@google.com&gt;
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Co-developed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Signed-off-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Tested-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Tested-by: Andreas Hindborg &lt;a.hindborg@kernel.org&gt;
Reviewed-by: Andreas Hindborg &lt;a.hindborg@kernel.org&gt;
Link: https://patch.msgid.link/20260203-inline-helpers-v2-3-beb8547a03c9@google.com
[ Some changes, apart from the rebase:

  - Added "(EXPERIMENTAL)" to Kconfig as the commit mentions.

  - Added `depends on ARM64 || X86_64` and `!UML` for now, since this is
    experimental, other architectures may require other changes (e.g.
    the issues I mentioned in the mailing list for ARM and UML) and they
    are not really tested so far. So let arch maintainers pick this up
    if they think it is worth it.

  - Gated the `cmd_ld_single` step also into the new mode, which also
    means that any possible future `objcopy` step is done after the
    translation, as expected.

  - Added `.gitignore` for `.bc` with exception for existing script.

  - Added `part-of-*` for helpers bitcode files as discussed, and
    dropped `$(if $(filter %_module.bc,$@),-DMODULE)` since `-DMODULE`
    is already there (would be duplicated otherwise).

  - Moved `LLVM_LINK` to keep binutils list alphabetized.

  - Fixed typo in title.

  - Dropped second `cmd_ld_single` commit message paragraph.

      - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: add `const_assert!` macro</title>
<updated>2026-03-30T00:03:49+00:00</updated>
<author>
<name>Gary Guo</name>
<email>gary@garyguo.net</email>
</author>
<published>2026-03-19T12:16:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=560a7a9b9267fbe31a68270ca0ad22b6a4db44a5'/>
<id>560a7a9b9267fbe31a68270ca0ad22b6a4db44a5</id>
<content type='text'>
The macro is a more powerful version of `static_assert!` for use inside
function contexts. This is powered by inline consts, so enable the feature
for old compiler versions that does not have it stably.

While it is possible already to write `const { assert!(...) }`, this
provides a short hand that is more uniform with other assertions. It also
formats nicer with rustfmt where it will not be formatted into multiple
lines.

Two users that would route via the Rust tree are converted.

Reviewed-by: Yury Norov &lt;ynorov@nvidia.com&gt;
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Alexandre Courbot &lt;acourbot@nvidia.com&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
Link: https://patch.msgid.link/20260319121653.2975748-3-gary@kernel.org
[ Rebased. Fixed period typo. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The macro is a more powerful version of `static_assert!` for use inside
function contexts. This is powered by inline consts, so enable the feature
for old compiler versions that does not have it stably.

While it is possible already to write `const { assert!(...) }`, this
provides a short hand that is more uniform with other assertions. It also
formats nicer with rustfmt where it will not be formatted into multiple
lines.

Two users that would route via the Rust tree are converted.

Reviewed-by: Yury Norov &lt;ynorov@nvidia.com&gt;
Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Alexandre Courbot &lt;acourbot@nvidia.com&gt;
Reviewed-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Reviewed-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
Link: https://patch.msgid.link/20260319121653.2975748-3-gary@kernel.org
[ Rebased. Fixed period typo. - Miguel ]
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: enable the `generic_arg_infer` feature</title>
<updated>2026-03-17T19:03:45+00:00</updated>
<author>
<name>Alexandre Courbot</name>
<email>acourbot@nvidia.com</email>
</author>
<published>2026-03-14T01:06:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3cc319d5f433a4d560cc944ecfb1fe50b866cd66'/>
<id>3cc319d5f433a4d560cc944ecfb1fe50b866cd66</id>
<content type='text'>
This feature is stable since 1.89, and used in subsequent patches.

Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Tested-by: Dirk Behme &lt;dirk.behme@de.bosch.com&gt;
Acked-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Signed-off-by: Alexandre Courbot &lt;acourbot@nvidia.com&gt;
Link: https://patch.msgid.link/20260314-register-v9-1-86805b2f7e9d@nvidia.com
[ Resolve merge conflict. - Danilo ]
Signed-off-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This feature is stable since 1.89, and used in subsequent patches.

Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Tested-by: Dirk Behme &lt;dirk.behme@de.bosch.com&gt;
Acked-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Signed-off-by: Alexandre Courbot &lt;acourbot@nvidia.com&gt;
Link: https://patch.msgid.link/20260314-register-v9-1-86805b2f7e9d@nvidia.com
[ Resolve merge conflict. - Danilo ]
Signed-off-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: ptr: add projection infrastructure</title>
<updated>2026-03-07T22:06:17+00:00</updated>
<author>
<name>Gary Guo</name>
<email>gary@garyguo.net</email>
</author>
<published>2026-03-02T16:42:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f41941aab3acd33f13d65a2ae496329bc8ae4de0'/>
<id>f41941aab3acd33f13d65a2ae496329bc8ae4de0</id>
<content type='text'>
Add a generic infrastructure for performing field and index projections on
raw pointers. This will form the basis of performing I/O projections.

Pointers manipulations are intentionally using the safe wrapping variants
instead of the unsafe variants, as the latter requires pointers to be
inside an allocation which is not necessarily true for I/O pointers.

This projection macro protects against rogue `Deref` implementation, which
can causes the projected pointer to be outside the bounds of starting
pointer. This is extremely unlikely and Rust has a lint to catch this, but
is unsoundness regardless. The protection works by inducing type inference
ambiguity when `Deref` is implemented.

This projection macro also stops projecting into unaligned fields (i.e.
fields of `#[repr(packed)]` structs), as misaligned pointers require
special handling. This is implemented by attempting to create reference to
projected field inside a `if false` block. Despite being unreachable, Rust
still checks that they're not unaligned fields.

The projection macro supports both fallible and infallible index
projections. These are described in detail inside the documentation.

Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Benno Lossin &lt;lossin@kernel.org&gt;
Acked-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Link: https://patch.msgid.link/20260302164239.284084-3-gary@kernel.org
[ * Add intro-doc links where possible,
  * Fix typos and slightly improve wording, e.g. "as documentation
    describes" -&gt; "as the documentation of [`Self::proj`] describes",
  * Add an empty line between regular and safety comments, before
    examples, and between logically independent comments,
  * Capitalize various safety comments.

    - Danilo ]
Signed-off-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a generic infrastructure for performing field and index projections on
raw pointers. This will form the basis of performing I/O projections.

Pointers manipulations are intentionally using the safe wrapping variants
instead of the unsafe variants, as the latter requires pointers to be
inside an allocation which is not necessarily true for I/O pointers.

This projection macro protects against rogue `Deref` implementation, which
can causes the projected pointer to be outside the bounds of starting
pointer. This is extremely unlikely and Rust has a lint to catch this, but
is unsoundness regardless. The protection works by inducing type inference
ambiguity when `Deref` is implemented.

This projection macro also stops projecting into unaligned fields (i.e.
fields of `#[repr(packed)]` structs), as misaligned pointers require
special handling. This is implemented by attempting to create reference to
projected field inside a `if false` block. Despite being unreachable, Rust
still checks that they're not unaligned fields.

The projection macro supports both fallible and infallible index
projections. These are described in detail inside the documentation.

Signed-off-by: Gary Guo &lt;gary@garyguo.net&gt;
Reviewed-by: Benno Lossin &lt;lossin@kernel.org&gt;
Acked-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
Link: https://patch.msgid.link/20260302164239.284084-3-gary@kernel.org
[ * Add intro-doc links where possible,
  * Fix typos and slightly improve wording, e.g. "as documentation
    describes" -&gt; "as the documentation of [`Self::proj`] describes",
  * Add an empty line between regular and safety comments, before
    examples, and between logically independent comments,
  * Capitalize various safety comments.

    - Danilo ]
Signed-off-by: Danilo Krummrich &lt;dakr@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'kbuild-fixes-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux</title>
<updated>2026-01-31T16:21:32+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-01-31T16:21:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=44f4119c7c6aac5f6d476b51a0bc62dcbfcaad12'/>
<id>44f4119c7c6aac5f6d476b51a0bc62dcbfcaad12</id>
<content type='text'>
Pull Kbuild fixes from Nicolas Schier:

 - Generate rpm-pkg debuginfo package manually, allowing signed kernel
   modules in rpm package, again

 - Fix permissions of modules.builtin.modinfo

 - Do not run kernel-doc when building external modules

* tag 'kbuild-fixes-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
  kbuild: Do not run kernel-doc when building external modules
  kbuild: Fix permissions of modules.builtin.modinfo
  kbuild: rpm-pkg: Generate debuginfo package manually
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull Kbuild fixes from Nicolas Schier:

 - Generate rpm-pkg debuginfo package manually, allowing signed kernel
   modules in rpm package, again

 - Fix permissions of modules.builtin.modinfo

 - Do not run kernel-doc when building external modules

* tag 'kbuild-fixes-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
  kbuild: Do not run kernel-doc when building external modules
  kbuild: Fix permissions of modules.builtin.modinfo
  kbuild: rpm-pkg: Generate debuginfo package manually
</pre>
</div>
</content>
</entry>
<entry>
<title>kbuild: Do not run kernel-doc when building external modules</title>
<updated>2026-01-31T15:12:01+00:00</updated>
<author>
<name>Nathan Chancellor</name>
<email>nathan@kernel.org</email>
</author>
<published>2026-01-30T21:37:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8e24994872361212531a952c93adb01c485148f1'/>
<id>8e24994872361212531a952c93adb01c485148f1</id>
<content type='text'>
After commit 778b8ebe5192 ("docs: Move the python libraries to
tools/lib/python"), building an external module with any value of W=
against the output of install-extmod-build fails with:

  $ make -C /usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build M=$PWD W=1
  make: Entering directory '/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build'
  make[1]: Entering directory '...'
    CC [M] ...
  Traceback (most recent call last):
    File "/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build/scripts/kernel-doc.py", line 339, in &lt;module&gt;
      main()
      ~~~~^^
    File "/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build/scripts/kernel-doc.py", line 295, in main
      from kdoc.kdoc_files import KernelFiles             # pylint: disable=C0415
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ModuleNotFoundError: No module named 'kdoc'

scripts/lib was included in the build directory from find_in_scripts but
after the move to tools/lib/python, it is no longer included, breaking
kernel-doc.py.

Commit eba6ffd126cd ("docs: kdoc: move kernel-doc to tools/docs") breaks
this even further by moving kernel-doc outside of scripts as well, so it
cannot be found when called by cmd_checkdoc.

  $ make -C /usr/lib/modules/6.19.0-rc7-next-20260130/build M=$PWD W=1
  make: Entering directory '/usr/lib/modules/6.19.0-rc7-next-20260130/build'
  make[1]: Entering directory '...'
    CC [M]  ...
  python3: can't open file '/usr/lib/modules/6.19.0-rc7-next-20260130/build/tools/docs/kernel-doc': [Errno 2] No such file or directory

While kernel-doc could be useful for external modules, it is more useful
for in-tree documentation that will be build and included in htmldocs.
Rather than including it in install-extmod-build, just skip running
kernel-doc for the external module build.

Cc: stable@vger.kernel.org
Fixes: 778b8ebe5192 ("docs: Move the python libraries to tools/lib/python")
Reported-by: Rong Zhang &lt;i@rong.moe&gt;
Closes: https://lore.kernel.org/20260129175321.415295-1-i@rong.moe/
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Signed-off-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Reviewed-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Link: https://patch.msgid.link/20260130-kbuild-skip-kernel-doc-extmod-v1-1-58443d60131a@kernel.org
Reviewed-by: Nicolas Schier &lt;nsc@kernel.org&gt;
Signed-off-by: Nicolas Schier &lt;nsc@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
After commit 778b8ebe5192 ("docs: Move the python libraries to
tools/lib/python"), building an external module with any value of W=
against the output of install-extmod-build fails with:

  $ make -C /usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build M=$PWD W=1
  make: Entering directory '/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build'
  make[1]: Entering directory '...'
    CC [M] ...
  Traceback (most recent call last):
    File "/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build/scripts/kernel-doc.py", line 339, in &lt;module&gt;
      main()
      ~~~~^^
    File "/usr/lib/modules/6.19.0-rc7-00108-g4d310797262f/build/scripts/kernel-doc.py", line 295, in main
      from kdoc.kdoc_files import KernelFiles             # pylint: disable=C0415
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ModuleNotFoundError: No module named 'kdoc'

scripts/lib was included in the build directory from find_in_scripts but
after the move to tools/lib/python, it is no longer included, breaking
kernel-doc.py.

Commit eba6ffd126cd ("docs: kdoc: move kernel-doc to tools/docs") breaks
this even further by moving kernel-doc outside of scripts as well, so it
cannot be found when called by cmd_checkdoc.

  $ make -C /usr/lib/modules/6.19.0-rc7-next-20260130/build M=$PWD W=1
  make: Entering directory '/usr/lib/modules/6.19.0-rc7-next-20260130/build'
  make[1]: Entering directory '...'
    CC [M]  ...
  python3: can't open file '/usr/lib/modules/6.19.0-rc7-next-20260130/build/tools/docs/kernel-doc': [Errno 2] No such file or directory

While kernel-doc could be useful for external modules, it is more useful
for in-tree documentation that will be build and included in htmldocs.
Rather than including it in install-extmod-build, just skip running
kernel-doc for the external module build.

Cc: stable@vger.kernel.org
Fixes: 778b8ebe5192 ("docs: Move the python libraries to tools/lib/python")
Reported-by: Rong Zhang &lt;i@rong.moe&gt;
Closes: https://lore.kernel.org/20260129175321.415295-1-i@rong.moe/
Reviewed-by: Mauro Carvalho Chehab &lt;mchehab+huawei@kernel.org&gt;
Signed-off-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Reviewed-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Link: https://patch.msgid.link/20260130-kbuild-skip-kernel-doc-extmod-v1-1-58443d60131a@kernel.org
Reviewed-by: Nicolas Schier &lt;nsc@kernel.org&gt;
Signed-off-by: Nicolas Schier &lt;nsc@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rust: kbuild: give `--config-path` to `rustfmt` in `.rsi` target</title>
<updated>2026-01-18T19:24:15+00:00</updated>
<author>
<name>Miguel Ojeda</name>
<email>ojeda@kernel.org</email>
</author>
<published>2026-01-15T18:38:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=af20ae33e7dd949f2e770198e74ac8f058cb299d'/>
<id>af20ae33e7dd949f2e770198e74ac8f058cb299d</id>
<content type='text'>
`rustfmt` is configured via the `.rustfmt.toml` file in the source tree,
and we apply `rustfmt` to the macro expanded sources generated by the
`.rsi` target.

However, under an `O=` pointing to an external folder (i.e. not just
a subdir), `rustfmt` will not find the file when checking the parent
folders. Since the edition is configured in this file, this can lead to
errors when it encounters newer syntax, e.g.

    error: expected one of `!`, `.`, `::`, `;`, `?`, `where`, `{`, or an operator, found `"rust_minimal"`
      --&gt; samples/rust/rust_minimal.rsi:29:49
       |
    28 | impl ::kernel::ModuleMetadata for RustMinimal {
       |                                               - while parsing this item list starting here
    29 |     const NAME: &amp;'static ::kernel::str::CStr = c"rust_minimal";
       |                                                 ^^^^^^^^^^^^^^ expected one of 8 possible tokens
    30 | }
       | - the item list ends here
       |
       = note: you may be trying to write a c-string literal
       = note: c-string literals require Rust 2021 or later
       = help: pass `--edition 2024` to `rustc`
       = note: for more on editions, read https://doc.rust-lang.org/edition-guide

A workaround is to use `RUSTFMT=n`, which is documented in the `Makefile`
help for cases where macro expanded source may happen to break `rustfmt`
for other reasons, but this is not one of those cases.

One solution would be to pass `--edition`, but we want `rustfmt` to
use the entire configuration, even if currently we essentially use the
default configuration.

Thus explicitly give the path to the config file to `rustfmt` instead.

Reported-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Fixes: 2f7ab1267dc9 ("Kbuild: add Rust support")
Cc: stable@vger.kernel.org
Reviewed-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260115183832.46595-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
`rustfmt` is configured via the `.rustfmt.toml` file in the source tree,
and we apply `rustfmt` to the macro expanded sources generated by the
`.rsi` target.

However, under an `O=` pointing to an external folder (i.e. not just
a subdir), `rustfmt` will not find the file when checking the parent
folders. Since the edition is configured in this file, this can lead to
errors when it encounters newer syntax, e.g.

    error: expected one of `!`, `.`, `::`, `;`, `?`, `where`, `{`, or an operator, found `"rust_minimal"`
      --&gt; samples/rust/rust_minimal.rsi:29:49
       |
    28 | impl ::kernel::ModuleMetadata for RustMinimal {
       |                                               - while parsing this item list starting here
    29 |     const NAME: &amp;'static ::kernel::str::CStr = c"rust_minimal";
       |                                                 ^^^^^^^^^^^^^^ expected one of 8 possible tokens
    30 | }
       | - the item list ends here
       |
       = note: you may be trying to write a c-string literal
       = note: c-string literals require Rust 2021 or later
       = help: pass `--edition 2024` to `rustc`
       = note: for more on editions, read https://doc.rust-lang.org/edition-guide

A workaround is to use `RUSTFMT=n`, which is documented in the `Makefile`
help for cases where macro expanded source may happen to break `rustfmt`
for other reasons, but this is not one of those cases.

One solution would be to pass `--edition`, but we want `rustfmt` to
use the entire configuration, even if currently we essentially use the
default configuration.

Thus explicitly give the path to the config file to `rustfmt` instead.

Reported-by: Alice Ryhl &lt;aliceryhl@google.com&gt;
Fixes: 2f7ab1267dc9 ("Kbuild: add Rust support")
Cc: stable@vger.kernel.org
Reviewed-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Reviewed-by: Gary Guo &lt;gary@garyguo.net&gt;
Link: https://patch.msgid.link/20260115183832.46595-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda &lt;ojeda@kernel.org&gt;
</pre>
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