Currently, Kbuild always operates in the output directory of the kernel,
even when building external modules. This increases the risk of external
module Makefiles attempting to write to the kernel directory.

This commit switches the working directory to the external module
directory, allowing the removal of the $(KBUILD_EXTMOD)/ prefix from
some build artifacts.

The command for building external modules maintains backward
compatibility, but Makefiles that rely on working in the kernel
directory may break. In such cases, $(objtree) and $(srctree) should
be used to refer to the output and source directories of the kernel.

The appearance of the build log will change as follows:

[Before]

  $ make -C /path/to/my/linux M=/path/to/my/externel/module
  make: Entering directory '/path/to/my/linux'
    CC [M]  /path/to/my/externel/module/helloworld.o
    MODPOST /path/to/my/externel/module/Module.symvers
    CC [M]  /path/to/my/externel/module/helloworld.mod.o
    CC [M]  /path/to/my/externel/module/.module-common.o
    LD [M]  /path/to/my/externel/module/helloworld.ko
  make: Leaving directory '/path/to/my/linux'

[After]

  $ make -C /path/to/my/linux M=/path/to/my/externel/module
  make: Entering directory '/path/to/my/linux'
  make[1]: Entering directory '/path/to/my/externel/module'
    CC [M]  helloworld.o
    MODPOST Module.symvers
    CC [M]  helloworld.mod.o
    CC [M]  .module-common.o
    LD [M]  helloworld.ko
  make[1]: Leaving directory '/path/to/my/externel/module'
  make: Leaving directory '/path/to/my/linux'

Printing "Entering directory" twice is cumbersome. This will be
addressed later.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>

When I merged the rust 'use' imports, I didn't realize that there's
an offical preferred idiomatic format - so while it all worked fine,
it doesn't match what 'make rustfmt' wants to make it.

Fix it up appropriately.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We were accidentally allocating a layout for the *square* of the object
size due to a variable shadowing mishap.

Fixes memory bloat and page allocation failures in drm/asahi.

Reported-by: Janne Grunau <j@jannau.net>
Fixes: 9e7bbfa1 ("rust: alloc: introduce `ArrayLayout`")
Signed-off-by: Asahi Lina <lina@asahilina.net>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Link: https://lore.kernel.org/r/20241123-rust-fix-arraylayout-v1-1-197e64c95bd4@asahilina.net


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

After a source tree build of the kernel, and having used the `RSCPP`
rule, running `rustfmt` fails with:

    error: macros that expand to items must be delimited with braces or followed by a semicolon
     --> rust/kernel/arch_static_branch_asm.rs:1:27
      |
    1 | ...ls!("1: jmp " ... ".popsection \n\t")
      |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      |
    help: change the delimiters to curly braces
      |
    1 | ::kernel::concat_literals!{"1: jmp " ... ".popsection \n\t"}
      |                           ~                                ~
    help: add a semicolon
      |
    1 | ::kernel::concat_literals!("1: jmp " ... ".popsection \n\t");
      |                                                             +

This file is not meant to be formatted nor works on its own since it is
meant to be textually included.

Thus skip formatting it by prefixing its name with `generated_`.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Link: https://lore.kernel.org/20241120175916.58860-1-ojeda@kernel.org


Fixes: 169484ab ("rust: add arch_static_branch")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

When building the rust_print sample with CONFIG_JUMP_LABEL=n, the Rust
static key support falls back to using static_key_count. This function
accepts a mutable pointer to the `struct static_key`, but the Rust
abstractions are incorrectly passing a const pointer.

This means that builds using CONFIG_JUMP_LABEL=n and SAMPLE_RUST_PRINT=y
fail with the following error message:

	error[E0308]: mismatched types
	  --> <root>/samples/rust/rust_print_main.rs:87:5
	   |
	87 | /     kernel::declare_trace! {
	88 | |         /// # Safety
	89 | |         ///
	90 | |         /// Always safe to call.
	91 | |         unsafe fn rust_sample_loaded(magic: c_int);
	92 | |     }
	   | |     ^
	   | |     |
	   | |_____types differ in mutability
	   |       arguments to this function are incorrect
	   |
	   = note: expected raw pointer `*mut kernel::bindings::static_key`
	              found raw pointer `*const kernel::bindings::static_key`
	note: function defined here
	  --> <root>/rust/bindings/bindings_helpers_generated.rs:33:12
	   |
	33 |     pub fn static_key_count(key: *mut static_key) -> c_int;
	   |            ^^^^^^^^^^^^^^^^

To fix this, insert a pointer cast so that the pointer is mutable.

Link: https://lore.kernel.org/20241118202727.73646-1-aliceryhl@google.com


Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202411181440.qEdcuyh6-lkp@intel.com/


Fixes: 169484ab ("rust: add arch_static_branch")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

`Result` is used in place of `Result<()>` because the default type
parameters are unit `()` and `Error` types, which are automatically
inferred. Thus keep the usage consistent throughout codebase.

Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1128


Signed-off-by: Manas <manas18244@iiitd.ac.in>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20241118-simplify-result-v3-1-6b1566a77eab@iiitd.ac.in


Signed-off-by: Jens Axboe <axboe@kernel.dk>

When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using
spinlock_check() + __raw_spin_lock_init() to initialize spin locks is
incorrect, and would cause build errors.

Introduce __spin_lock_init() to initialize a spin lock with lockdep
rquired information for PREEMPT_RT builds, and use it in the Rust
helper.

Fixes: d2d6422f ("x86: Allow to enable PREEMPT_RT.")
Closes: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@intel.com/


Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241107163223.2092690-2-ezulian@redhat.com

Currently FFI integer types are defined in libcore. This commit creates
the `ffi` crate and asks bindgen to use that crate for FFI integer types
instead of `core::ffi`.

This commit is preparatory and no type changes are made in this commit
yet.

Signed-off-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net


[ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of
  `rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate
  docs slightly and formatted. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Currently bindgen has special logic to recognise `size_t` and `ssize_t`
and map them to Rust `usize` and `isize`. Similarly, `ptrdiff_t` is
mapped to `isize`.

However this falls short for `__kernel_size_t`, `__kernel_ssize_t` and
`__kernel_ptrdiff_t`. To ensure that they are mapped to usize/isize
rather than 32/64 integers depending on platform, blocklist them in
bindgen parameters and manually provide their definition.

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Link: https://lore.kernel.org/r/20240913213041.395655-3-gary@garyguo.net


[ Formatted comment. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Without `-fno-builtin`, for functions like memcpy/memmove (and many
others), bindgen seems to be using the clang-provided prototype. This
prototype is ABI-wise compatible, but the issue is that it does not have
the same information as the source code w.r.t. typedefs.

For example, bindgen generates the following:

    extern "C" {
        pub fn strlen(s: *const core::ffi::c_char) -> core::ffi::c_ulong;
    }

note that the return type is `c_ulong` (i.e. unsigned long), despite the
size_t-is-usize behavior (this is default, and we have not opted out
from it using --no-size_t-is-usize).

Similarly, memchr's size argument should be of type `__kernel_size_t`,
but bindgen generates `c_ulong` directly.

We want to ensure any `size_t` is translated to Rust `usize` so that we
can avoid having them be different type on 32-bit and 64-bit
architectures, and hence would require a lot of excessive type casts
when calling FFI functions.

I found that this bindgen behavior (which probably is caused by
libclang) can be disabled by `-fno-builtin`. Using the flag for compiled
code can result in less optimisation because compiler cannot assume
about their properties anymore, but this should not affect bindgen.

[ Trevor asked: "I wonder how reliable this behavior is. Maybe bindgen
  could do a better job controlling this, is there an open issue?".

  Gary replied: ..."apparently this is indeed the suggested approach in
  https://github.com/rust-lang/rust-bindgen/issues/1770

". - Miguel ]

Signed-off-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240913213041.395655-2-gary@garyguo.net


[ Formatted comment. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Add support for creating global variables that are wrapped in a mutex or
spinlock.

The implementation here is intended to replace the global mutex
workaround found in the Rust Binder RFC [1]. In both cases, the global
lock must be initialized before first use. The macro is unsafe to use
for the same reason.

The separate initialization step is required because it is tricky to
access the value of __ARCH_SPIN_LOCK_UNLOCKED from Rust. Doing so will
require changes to the C side. That change will happen as a follow-up to
this patch.

Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-2-08ba9197f637@google.com/#Z31drivers:android:context.rs

 [1]
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241023-static-mutex-v6-1-d7efdadcc84f@google.com


[ Simplified a few intra-doc links. Formatted a few comments. Reworded
  title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Implement `dev_*` print macros for `device::Device`.

They behave like the macros with the same names in C, i.e., they print
messages to the kernel ring buffer with the given level, prefixing the
messages with corresponding device information.

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241022213221.2383-9-dakr@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows modules to be initialised in-place in pinned memory, which
enables the usage of pinned types (e.g., mutexes, spinlocks, driver
registrations, etc.) in modules without any extra allocations.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20241022213221.2383-3-dakr@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

To allow the Rust implementation of static_key_false to use runtime code
patching instead of the generic implementation, pull in the relevant
inline assembly from the jump_label.h header by running the C
preprocessor on a .rs.S file. Build rules are added for .rs.S files.

Since the relevant inline asm has been adjusted to export the inline asm
via the ARCH_STATIC_BRANCH_ASM macro in a consistent way, the Rust side
does not need architecture specific code to pull in the asm.

It is not possible to use the existing C implementation of
arch_static_branch via a Rust helper because it passes the argument
`key` to inline assembly as an 'i' parameter. Any attempt to add a C
helper for this function will fail to compile because the value of `key`
must be known at compile-time.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>
Link: https://lore.kernel.org/20241030-tracepoint-v12-5-eec7f0f8ad22@google.com


Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

This updates the Rust printing sample to invoke a tracepoint. This
ensures that we have a user in-tree from the get-go even though the
patch is being merged before its real user.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>
Link: https://lore.kernel.org/20241030-tracepoint-v12-3-eec7f0f8ad22@google.com


Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Make it possible to have Rust code call into tracepoints defined by C
code. It is still required that the tracepoint is declared in a C
header, and that this header is included in the input to bindgen.

Instead of calling __DO_TRACE directly, the exported rust_do_trace_
function calls an inline helper function. This is because the `cond`
argument does not exist at the callsite of DEFINE_RUST_DO_TRACE.

__DECLARE_TRACE always emits an inline static and an extern declaration
that is only used when CREATE_RUST_TRACE_POINTS is set. These should not
end up in the final binary so it is not a problem that they sometimes
are emitted without a user.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>
Link: https://lore.kernel.org/20241030-tracepoint-v12-2-eec7f0f8ad22@google.com


Reviewed-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Add just enough support for static key so that we can use it from
tracepoints. Tracepoints rely on `static_branch_unlikely` with a `struct
static_key_false`, so we add the same functionality to Rust.

This patch only provides a generic implementation without code patching
(matching the one used when CONFIG_JUMP_LABEL is disabled). Later
patches add support for inline asm implementations that use runtime
patching.

When CONFIG_JUMP_LABEL is unset, `static_key_count` is a static inline
function, so a Rust helper is defined for `static_key_count` in this
case. If Rust is compiled with LTO, this call should get inlined. The
helper can be eliminated once we have the necessary inline asm to make
atomic operations from Rust.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <bjorn3_gh@protonmail.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Andrew Jones <ajones@ventanamicro.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Conor Dooley <conor.dooley@microchip.com>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>
Link: https://lore.kernel.org/20241030-tracepoint-v12-1-eec7f0f8ad22@google.com


Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Now that the rusttest target for the macros crate is compiled with the
kernel crate as a dependency, the rest of the rustdoc tests can be
enabled.

Signed-off-by: Ethan D. Twardy <ethan.twardy@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1076
Link: https://lore.kernel.org/r/20240704145607.17732-5-ethan.twardy@gmail.com


[ Rebased (use `K{Box,Vec}` instead, enable `lint_reasons` feature).
  Remove unneeded `rust` as language in examples, as well as
  `#[macro_use]` `extern`s. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

According to the rustdoc for the proc_macro crate[1], tokens captured
from a "macro variable" (e.g. from within macro_rules!) may be delimited
by invisible tokens and be contained within a proc_macro::Group.

Previously, this scenario was not handled by macros::paste, which caused
a proc-macro panic when the corresponding tests are enabled. Enable the
tests, and handle this case by making macros::paste::concat recursive.

Link: https://doc.rust-lang.org/stable/proc_macro/enum.Delimiter.html

 [1]
Signed-off-by: Ethan D. Twardy <ethan.twardy@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1076
Link: https://lore.kernel.org/r/20240704145607.17732-4-ethan.twardy@gmail.com


[ Rebased (one fix was already applied) and reworded. Remove unneeded
  `rust` as language in examples. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Previously, these tests were ignored due to a missing necessary dependency
on the `kernel` crate. Enable the tests, and update them: for both,
add the parameter to `init()`; for the first one, remove the use of a
kernel parameter mechanism that was never merged.

Signed-off-by: Ethan D. Twardy <ethan.twardy@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1076
Link: https://lore.kernel.org/r/20240704145607.17732-3-ethan.twardy@gmail.com


[ Rebased (moved the `export` to the `rustdoc_test` rule, enable the
  firmware example too). Removed `export` for `RUST_MODFILE`. Removed
  unneeded `rust` language in examples, as well as `#[macro_use]`
  `extern`s. Reworded accordingly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Previously, the rusttest target for the macros crate did not specify
the dependencies necessary to run the rustdoc tests. These tests rely on
the kernel crate, so add the dependencies.

Signed-off-by: Ethan D. Twardy <ethan.twardy@gmail.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1076
Link: https://lore.kernel.org/r/20240704145607.17732-2-ethan.twardy@gmail.com


[ Rebased (`alloc` is gone nowadays, sysroot handling is simpler) and
  simplified (reused `rustdoc_test` rule instead of adding a new one,
  no need for `rustdoc-compiler_builtins`, removed unneeded `macros`
  explicit path). Made `vtable` example fail (avoiding to increase
  the complexity in the `rusttest` target). Removed unstable
  `-Zproc-macro-backtrace` option. Reworded accordingly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Update the `Opaque` documentation and add an example as proposed by
Miguel Ojeda in [1]. The documentation update is mainly taken from
Benno Lossin's description [2].

Cc: Nell Shamrell-Harrington <nells@linux.microsoft.com>
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565/topic/x/near/467478085 [1]
Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565/topic/x/near/470498289

 [2]
Co-developed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Link: https://lore.kernel.org/r/20241002050301.1927545-1-dirk.behme@de.bosch.com


[ Used `expect`. Rewrapped docs. Added intra-doc link. Formatted
  example. Reworded to fix tag typo/order. Fixed `&mut` formatting
  as discussed. Added Benno's SOB and CDB as discussed. Shortened
  links. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Fix several issues with rustdoc formatting for the
`kernel::block::mq::Request` module, in particular:

  - An ordered list not rendering correctly, fixed by using numbers
    prefixes instead of letters.

  - Code snippets formatted as regular text, fixed by wrapping the
    code with `back-ticks`.

  - References to types missing intra-doc links, fixed by wrapping the
    types with [square brackets].

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://github.com/Rust-for-Linux/linux/issues/1108


Signed-off-by: Francesco Zardi <frazar00@gmail.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Fixes: 3253aba3 ("rust: block: introduce `kernel::block::mq` module")
Link: https://lore.kernel.org/r/20240903173027.16732-3-frazar00@gmail.com


[ Added an extra intra-doc link. Took the chance to add some periods
  for consistency. Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This fixes the following four warnings:

	warning: unsafe block missing a safety comment
	   --> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:168:15
	    |
	168 |             ..unsafe { MaybeUninit::zeroed().assume_init() }
	    |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	    |
	    = help: consider adding a safety comment on the preceding line
	    = help: for further information visit
	      https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
	    = note: requested on the command line with `-W clippy::undocumented-unsafe-blocks`

	warning: unsafe function's docs are missing a `# Safety` section
	   --> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:175:1
	    |
	175 | / unsafe extern "C" fn fops_open<T: MiscDevice>(
	176 | |     inode: *mut bindings::inode,
	177 | |     file: *mut bindings::file,
	178 | | ) -> c_int {
	    | |__________^
	    |
	    = help: for further information visit
	      https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc
	    = note: `-W clippy::missing-safety-doc` implied by `-W clippy::all`
	    = help: to override `-W clippy::all` add `#[allow(clippy::missing_safety_doc)]`

	warning: unsafe function's docs are missing a `# Safety` section
	   --> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:196:1
	    |
	196 | / unsafe extern "C" fn fops_release<T: MiscDevice>(
	197 | |     _inode: *mut bindings::inode,
	198 | |     file: *mut bindings::file,
	199 | | ) -> c_int {
	    | |__________^
	    |
	    = help: for further information visit
	      https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc

	warning: unsafe function's docs are missing a `# Safety` section
	   --> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:210:1
	    |
	210 | / unsafe extern "C" fn fops_ioctl<T: MiscDevice>(
	211 | |     file: *mut bindings::file,
	212 | |     cmd: c_uint,
	213 | |     arg: c_ulong,
	214 | | ) -> c_long {
	    | |___________^
	    |
	    = help: for further information visit
	      https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc



Note that these warnings are currently not enabled in the build, but
rust-next contains a commit that will enable them, so we should fix
them.

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Closes: https://lore.kernel.org/rust-for-linux/CANiq72kOs6vPDUzZttQNqePFHphCQ30iVmZ5MO7eCJfPG==Vzg@mail.gmail.com/


Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20241022-miscdevice-unsafe-warn-fix-v1-1-a78fde1740d6@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

One of the example in this section uses a curious mix of the constant
and function declaration syntaxes; fix it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Fixes: 823d4737 ("rust: macros: add `paste!` proc macro")
Link: https://lore.kernel.org/r/20241019072208.1016707-1-pbonzini@redhat.com


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

The doc comment for `ThisModule` incorrectly states the C header file
for `THIS_MODULE` as `include/linux/export.h`, while the correct path is
`include/linux/init.h`. This is because `THIS_MODULE` was moved in
commit 5b20755b ("init: move THIS_MODULE from <linux/export.h> to
<linux/init.h>").

Update the doc comment for `ThisModule` to reflect the correct header
file path for `THIS_MODULE`.

Fixes: 5b20755b ("init: move THIS_MODULE from <linux/export.h> to <linux/init.h>")
Signed-off-by: Yutaro Ohno <yutaro.ono.418@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/ZxXDZwxWgoEiIYkj@ohnotp


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This is a useful for helper for working with indices into buffers that
consist of several pages. I forgot to include it when I added PAGE_SIZE
and PAGE_MASK for the same purpose in commit fc6e66f4 ("rust: add
abstraction for `struct page`").

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241016-page-align-v2-1-e0afe85fc4b4@google.com


[ Added intra-doc links, formatted comment and replaced "Brackets" with
  "Parentheses" as discussed in the list. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Commit e26fa546 ("rust: kbuild: auto generate helper exports")
removed the need for these by automatically generating the exports; it
removed the explicit uses of `EXPORT_SYMBOL_GPL` but didn't remove the
`#include <linux/export.h>`s.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20241009162553.27845-2-tamird@gmail.com


[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Commit e26fa546 ("rust: kbuild: auto generate helper exports")
added an errant "the" where one was not needed; remove it.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Reviewed-by: Dirk Behme <dirk.behme@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20241009162358.27735-1-tamird@gmail.com


[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now that we have our own `Allocator`, `Box` and `Vec` types we can remove
Rust's `alloc` crate and the `new_uninit` unstable feature.

Also remove `Kmalloc`'s `GlobalAlloc` implementation -- we can't remove
this in a separate patch, since the `alloc` crate requires a
`#[global_allocator]` to set, that implements `GlobalAlloc`.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-29-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Before we remove Rust's alloc crate, rewrite the module comment in
alloc.rs to avoid a rustdoc warning.

Besides that, the module comment in alloc.rs isn't correct anymore,
we're no longer extending Rust's alloc crate.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-28-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

The current implementation of tests in str.rs use `format!` to format
strings for comparison, which, internally, creates a new `String`.

In order to prepare for getting rid of Rust's alloc crate, we have to
cut this dependency. Instead, implement `format!` for `CString`.

Note that for userspace tests, `Kmalloc`, which is backing `CString`'s
memory, is just a type alias to `Cmalloc`.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-27-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

So far the kernel's `Box` and `Vec` types can't be used by userspace
test cases, since all users of those types (e.g. `CString`) use kernel
allocators for instantiation.

In order to allow userspace test cases to make use of such types as
well, implement the `Cmalloc` allocator within the allocator_test module
and type alias all kernel allocators to `Cmalloc`. The `Cmalloc`
allocator uses libc's `realloc()` function as allocator backend.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-26-dakr@kernel.org


[ Removed the temporary `allow(dead_code)` as discussed in the list and
  fixed typo, added backticks. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Provide a simple helper function to check whether given flags do
contain one or multiple other flags.

This is used by a subsequent patch implementing the Cmalloc `Allocator`
to check for __GFP_ZERO.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-25-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Additional to `testlib` also check for `test` in `Error::name`. This is
required by a subsequent patch that (indirectly) uses `Error` in test
cases.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-24-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Use `core::alloc::LayoutError` instead of `alloc::alloc::LayoutError` in
preparation to get rid of Rust's alloc crate.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-23-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now that we removed `VecExt` and the corresponding includes in
prelude.rs, add the new kernel `Vec` type instead.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-22-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now that all existing `Vec` users were moved to the kernel `Vec` type,
remove the `VecExt` extension.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-21-dakr@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now that we got the kernel `Vec` in place, convert all existing `Vec`
users to make use of it.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-20-dakr@kernel.org


[ Converted `kasan_test_rust.rs` too, as discussed. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Currently, we can't implement `FromIterator`. There are a couple of
issues with this trait in the kernel, namely:

  - Rust's specialization feature is unstable. This prevents us to
    optimize for the special case where `I::IntoIter` equals `Vec`'s
    `IntoIter` type.
  - We also can't use `I::IntoIter`'s type ID either to work around this,
    since `FromIterator` doesn't require this type to be `'static`.
  - `FromIterator::from_iter` does return `Self` instead of
    `Result<Self, AllocError>`, hence we can't properly handle allocation
    failures.
  - Neither `Iterator::collect` nor `FromIterator::from_iter` can handle
    additional allocation flags.

Instead, provide `IntoIter::collect`, such that we can at least convert
`IntoIter` into a `Vec` again.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241004154149.93856-19-dakr@kernel.org


[ Added newline in documentation, changed case of section to be
  consistent with an existing one, fixed typo. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>