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Author SHA1 Message Date
Miguel Ojeda
8af7a50167 rust: jump_label: skip formatting generated file 
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: 169484ab6677 ("rust: add arch_static_branch")
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
 2024-11-20 13:32:42 -05:00
Alice Ryhl
7643155dce jump_label: rust: pass a mut ptr to static_key_count 
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: 169484ab6677 ("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>
 2024-11-18 17:09:28 -05:00
Alice Ryhl
169484ab66 rust: add arch_static_branch 
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>
 2024-11-04 16:21:45 -05:00
Alice Ryhl
6e59bcc9c8 rust: add static_branch_unlikely for static_key_false 
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>
 2024-11-04 16:21:44 -05:00