[PATCH v10 4/5] rust: replace `kernel::c_str!` with C-Strings
From: Tamir Duberstein <hidden>
Date: 2025-05-24 20:33:32
Also in:
dri-devel, linux-block, linux-devicetree, linux-kselftest, linux-pci, lkml, llvm, nouveau, rust-for-linux
Subsystem:
applied micro qt2025 phy driver, asix phy driver [rust], char and misc drivers, core driver for nvidia gpus [rust], driver core, kobjects, debugfs and sysfs, drm drivers, drm drivers and common infrastructure [rust], ethernet phy library, ethernet phy library [rust], firmware loader (request_firmware), kernel unit testing framework (kunit), locking primitives, module support, networking drivers, pci subsystem [rust], rust, rust [sync], the rest · Maintainers:
FUJITA Tomonori, Arnd Bergmann, Greg Kroah-Hartman, Danilo Krummrich, Alexandre Courbot, "Rafael J. Wysocki", David Airlie, Simona Vetter, Alice Ryhl, Andrew Lunn, Heiner Kallweit, Luis Chamberlain, Russ Weight, Brendan Higgins, David Gow, Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng, Petr Pavlu, Daniel Gomez, Sami Tolvanen, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Miguel Ojeda, Gary Guo, Linus Torvalds
C-String literals were added in Rust 1.77. Replace instances of `kernel::c_str!` with C-String literals where possible and rename `kernel::c_str!` to `c_str_avoid_literals` to clarify its intended use. Closes: https://github.com/Rust-for-Linux/linux/issues/1075 Signed-off-by: Tamir Duberstein <redacted> --- drivers/gpu/nova-core/driver.rs | 2 +- drivers/net/phy/ax88796b_rust.rs | 7 +++---- drivers/net/phy/qt2025.rs | 5 ++--- rust/kernel/devres.rs | 2 +- rust/kernel/firmware.rs | 6 +++--- rust/kernel/kunit.rs | 7 ++++--- rust/kernel/net/phy.rs | 6 ++---- rust/kernel/platform.rs | 4 ++-- rust/kernel/str.rs | 38 ++++++++++++++++++++++++------------ rust/kernel/sync.rs | 7 +++---- rust/kernel/sync/lock/global.rs | 3 ++- rust/macros/kunit.rs | 6 +++--- rust/macros/module.rs | 2 +- samples/rust/rust_driver_faux.rs | 4 ++-- samples/rust/rust_driver_pci.rs | 4 ++-- samples/rust/rust_driver_platform.rs | 4 ++-- samples/rust/rust_misc_device.rs | 3 +-- 17 files changed, 59 insertions(+), 51 deletions(-)
diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index a08fb6599267..776970049974 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs@@ -33,7 +33,7 @@ fn probe(pdev: &pci::Device<Core>, _info: &Self::IdInfo) -> Result<Pin<KBox<Self pdev.enable_device_mem()?; pdev.set_master(); - let bar = pdev.iomap_region_sized::<BAR0_SIZE>(0, c_str!("nova-core/bar0"))?; + let bar = pdev.iomap_region_sized::<BAR0_SIZE>(0, c"nova-core/bar0")?; let this = KBox::pin_init( try_pin_init!(Self {
diff --git a/drivers/net/phy/ax88796b_rust.rs b/drivers/net/phy/ax88796b_rust.rs
index bc73ebccc2aa..2d24628a4e58 100644
--- a/drivers/net/phy/ax88796b_rust.rs
+++ b/drivers/net/phy/ax88796b_rust.rs@@ -5,7 +5,6 @@ //! //! C version of this driver: [`drivers/net/phy/ax88796b.c`](./ax88796b.c) use kernel::{ - c_str, net::phy::{self, reg::C22, DeviceId, Driver}, prelude::*, uapi,
@@ -41,7 +40,7 @@ fn asix_soft_reset(dev: &mut phy::Device) -> Result { #[vtable] impl Driver for PhyAX88772A { const FLAGS: u32 = phy::flags::IS_INTERNAL; - const NAME: &'static CStr = c_str!("Asix Electronics AX88772A"); + const NAME: &'static CStr = c"Asix Electronics AX88772A"; const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_exact_mask(0x003b1861); // AX88772A is not working properly with some old switches (NETGEAR EN 108TP):
@@ -105,7 +104,7 @@ fn link_change_notify(dev: &mut phy::Device) { #[vtable] impl Driver for PhyAX88772C { const FLAGS: u32 = phy::flags::IS_INTERNAL; - const NAME: &'static CStr = c_str!("Asix Electronics AX88772C"); + const NAME: &'static CStr = c"Asix Electronics AX88772C"; const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_exact_mask(0x003b1881); fn suspend(dev: &mut phy::Device) -> Result {
@@ -125,7 +124,7 @@ fn soft_reset(dev: &mut phy::Device) -> Result { #[vtable] impl Driver for PhyAX88796B { - const NAME: &'static CStr = c_str!("Asix Electronics AX88796B"); + const NAME: &'static CStr = c"Asix Electronics AX88796B"; const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_model_mask(0x003b1841); fn soft_reset(dev: &mut phy::Device) -> Result {
diff --git a/drivers/net/phy/qt2025.rs b/drivers/net/phy/qt2025.rs
index 0b9400dcb4c1..9ccc75f70219 100644
--- a/drivers/net/phy/qt2025.rs
+++ b/drivers/net/phy/qt2025.rs@@ -9,7 +9,6 @@ //! //! The QT2025 PHY integrates an Intel 8051 micro-controller. -use kernel::c_str; use kernel::error::code; use kernel::firmware::Firmware; use kernel::net::phy::{
@@ -36,7 +35,7 @@ #[vtable] impl Driver for PhyQT2025 { - const NAME: &'static CStr = c_str!("QT2025 10Gpbs SFP+"); + const NAME: &'static CStr = c"QT2025 10Gpbs SFP+"; const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x0043a400); fn probe(dev: &mut phy::Device) -> Result<()> {
@@ -69,7 +68,7 @@ fn probe(dev: &mut phy::Device) -> Result<()> { // The micro-controller will start running from the boot ROM. dev.write(C45::new(Mmd::PCS, 0xe854), 0x00c0)?; - let fw = Firmware::request(c_str!("qt2025-2.0.3.3.fw"), dev.as_ref())?; + let fw = Firmware::request(c"qt2025-2.0.3.3.fw", dev.as_ref())?; if fw.data().len() > SZ_16K + SZ_8K { return Err(code::EFBIG); }
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index ddb1ce4a78d9..8735b227f0d3 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs@@ -45,7 +45,7 @@ struct DevresInner<T> { /// # Example /// /// ```no_run -/// # use kernel::{bindings, c_str, device::Device, devres::Devres, io::{Io, IoRaw}}; +/// # use kernel::{bindings, device::Device, devres::Devres, io::{Io, IoRaw}}; /// # use core::ops::Deref; /// /// // See also [`pci::Bar`] for a real example.
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
index 582ab648b14c..09fd3a27bcf0 100644
--- a/rust/kernel/firmware.rs
+++ b/rust/kernel/firmware.rs@@ -51,13 +51,13 @@ fn request_nowarn() -> Self { /// # Examples /// /// ```no_run -/// # use kernel::{c_str, device::Device, firmware::Firmware}; +/// # use kernel::{device::Device, firmware::Firmware}; /// /// # fn no_run() -> Result<(), Error> { /// # // SAFETY: *NOT* safe, just for the example to get an `ARef<Device>` instance /// # let dev = unsafe { Device::get_device(core::ptr::null_mut()) }; /// -/// let fw = Firmware::request(c_str!("path/to/firmware.bin"), &dev)?; +/// let fw = Firmware::request(c"path/to/firmware.bin", &dev)?; /// let blob = fw.data(); /// /// # Ok(())
@@ -203,7 +203,7 @@ macro_rules! module_firmware { ($($builder:tt)*) => { const _: () = { const __MODULE_FIRMWARE_PREFIX: &'static $crate::str::CStr = if cfg!(MODULE) { - $crate::c_str!("") + c"" } else { <LocalModule as $crate::ModuleMetadata>::NAME };
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index e5621d596ed3..09148e982f48 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs@@ -58,9 +58,10 @@ macro_rules! kunit_assert { break 'out; } - static FILE: &'static $crate::str::CStr = $crate::c_str!($file); + static FILE: &'static $crate::str::CStr = $crate::c_str_avoid_literals!($file); static LINE: i32 = core::line!() as i32 - $diff; - static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($condition)); + static CONDITION: &'static $crate::str::CStr = + $crate::c_str_avoid_literals!(stringify!($condition)); // SAFETY: FFI call without safety requirements. let kunit_test = unsafe { $crate::bindings::kunit_get_current_test() };
@@ -222,7 +223,7 @@ pub const fn kunit_case_null() -> kernel::bindings::kunit_case { /// } /// /// static mut KUNIT_TEST_CASES: [kernel::bindings::kunit_case; 2] = [ -/// kernel::kunit::kunit_case(kernel::c_str!("name"), test_fn), +/// kernel::kunit::kunit_case(c"name", test_fn), /// kernel::kunit::kunit_case_null(), /// ]; /// kernel::kunit_unsafe_test_suite!(suite_name, KUNIT_TEST_CASES);
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 652e060e47bd..8129419a3931 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs@@ -780,7 +780,6 @@ const fn as_int(&self) -> u32 { /// /// ``` /// # mod module_phy_driver_sample { -/// use kernel::c_str; /// use kernel::net::phy::{self, DeviceId}; /// use kernel::prelude::*; ///
@@ -799,7 +798,7 @@ const fn as_int(&self) -> u32 { /// /// #[vtable] /// impl phy::Driver for PhySample { -/// const NAME: &'static CStr = c_str!("PhySample"); +/// const NAME: &'static CStr = c"PhySample"; /// const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001); /// } /// # }
@@ -808,7 +807,6 @@ const fn as_int(&self) -> u32 { /// This expands to the following code: /// /// ```ignore -/// use kernel::c_str; /// use kernel::net::phy::{self, DeviceId}; /// use kernel::prelude::*; ///
@@ -828,7 +826,7 @@ const fn as_int(&self) -> u32 { /// /// #[vtable] /// impl phy::Driver for PhySample { -/// const NAME: &'static CStr = c_str!("PhySample"); +/// const NAME: &'static CStr = c"PhySample"; /// const PHY_DEVICE_ID: phy::DeviceId = phy::DeviceId::new_with_exact_mask(0x00000001); /// } ///
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index fd4a494f30e8..7163fc468b32 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs@@ -124,7 +124,7 @@ macro_rules! module_platform_driver { /// # Example /// ///``` -/// # use kernel::{bindings, c_str, device::Core, of, platform}; +/// # use kernel::{bindings, device::Core, of, platform}; /// /// struct MyDriver; ///
@@ -133,7 +133,7 @@ macro_rules! module_platform_driver { /// MODULE_OF_TABLE, /// <MyDriver as platform::Driver>::IdInfo, /// [ -/// (of::DeviceId::new(c_str!("test,device")), ()) +/// (of::DeviceId::new(c"test,device"), ()) /// ] /// ); ///
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index 586644912414..0385d927fcd5 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs@@ -266,15 +266,14 @@ impl fmt::Display for crate::fmt::Adapter<&CStr> { /// Formats printable ASCII characters, escaping the rest. /// /// ``` - /// # use kernel::c_str; /// # use kernel::prelude::fmt; /// # use kernel::str::CStr; /// # use kernel::str::CString; - /// let penguin = c_str!("🐧"); + /// let penguin = c"🐧"; /// let s = CString::try_from_fmt(fmt!("{}", penguin))?; /// assert_eq!(s.to_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes()); /// - /// let ascii = c_str!("so \"cool\""); + /// let ascii = c"so \"cool\""; /// let s = CString::try_from_fmt(fmt!("{}", ascii))?; /// assert_eq!(s.to_bytes_with_nul(), "so \"cool\"\0".as_bytes()); /// # Ok::<(), kernel::error::Error>(())
@@ -365,25 +364,38 @@ fn as_ref(&self) -> &BStr { } } -/// Creates a new [`CStr`] from a string literal. +/// Creates a static C string wrapper at compile time. /// -/// The string literal should not contain any `NUL` bytes. +/// Rust supports C string literals since Rust 1.77, and they should be used instead of this macro +/// where possible. This macro exists to allow static *non-literal* C strings to be created at +/// compile time. This is most often used in other macros. +/// +/// # Panics +/// +/// This macro panics if the operand contains an interior `NUL` byte. /// /// # Examples /// /// ``` -/// # use kernel::c_str; +/// # use kernel::c_str_avoid_literals; /// # use kernel::str::CStr; -/// const MY_CSTR: &CStr = c_str!("My awesome CStr!"); +/// const MY_CSTR: &CStr = c_str_avoid_literals!(concat!(file!(), ":", line!(), ": My CStr!")); /// ``` #[macro_export] -macro_rules! c_str { +macro_rules! c_str_avoid_literals { + // NB: we could write `($str:lit) => compile_error!("use a C string literal instead");` here but + // that would trigger when the literal is at the top of several macro expansions. That would be + // too limiting to macro authors, so we rely on the name as a hint instead. ($str:expr) => {{ - const S: &str = concat!($str, "\0"); - const C: &$crate::str::CStr = match $crate::str::CStr::from_bytes_with_nul(S.as_bytes()) { - Ok(v) => v, - Err(_) => panic!("string contains interior NUL"), - }; + const S: &'static str = concat!($str, "\0"); + const C: &'static $crate::str::CStr = + match $crate::str::CStr::from_bytes_with_nul(S.as_bytes()) { + Ok(v) => v, + Err(err) => { + let _: core::ffi::FromBytesWithNulError = err; + panic!("string contains interior NUL") + } + }; C }}; }
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 36a719015583..424864fb448f 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs@@ -41,7 +41,6 @@ impl LockClassKey { /// /// # Example /// ``` - /// # use kernel::c_str; /// # use kernel::alloc::KBox; /// # use kernel::types::ForeignOwnable; /// # use kernel::sync::{LockClassKey, SpinLock};
@@ -53,7 +52,7 @@ impl LockClassKey { /// { /// stack_pin_init!(let num: SpinLock<u32> = SpinLock::new( /// 0, - /// c_str!("my_spinlock"), + /// c"my_spinlock", /// // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose /// // `from_foreign()` has not yet been called. /// unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) }
@@ -106,9 +105,9 @@ macro_rules! static_lock_class { #[macro_export] macro_rules! optional_name { () => { - $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!())) + $crate::c_str_avoid_literals!(::core::concat!(::core::file!(), ":", ::core::line!())) }; ($name:literal) => { - $crate::c_str!($name) + $crate::c_str_avoid_literals!($name) }; }
diff --git a/rust/kernel/sync/lock/global.rs b/rust/kernel/sync/lock/global.rs
index 79d0ef7fda86..0ca23b12427c 100644
--- a/rust/kernel/sync/lock/global.rs
+++ b/rust/kernel/sync/lock/global.rs@@ -267,7 +267,8 @@ macro_rules! global_lock { $pub enum $name {} impl $crate::sync::lock::GlobalLockBackend for $name { - const NAME: &'static $crate::str::CStr = $crate::c_str!(::core::stringify!($name)); + const NAME: &'static $crate::str::CStr = + $crate::c_str_avoid_literals!(::core::stringify!($name)); type Item = $valuety; type Backend = $crate::global_lock_inner!(backend $kind);
diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs
index 99ccac82edde..56469fdcee3f 100644
--- a/rust/macros/kunit.rs
+++ b/rust/macros/kunit.rs@@ -89,8 +89,8 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: *mut kernel::bindings::kunit) { bar(); } // // static mut TEST_CASES: [kernel::bindings::kunit_case; 3] = [ - // kernel::kunit::kunit_case(kernel::c_str!("foo"), kunit_rust_wrapper_foo), - // kernel::kunit::kunit_case(kernel::c_str!("bar"), kunit_rust_wrapper_bar), + // kernel::kunit::kunit_case(c"foo", kunit_rust_wrapper_foo), + // kernel::kunit::kunit_case(c"bar", kunit_rust_wrapper_bar), // kernel::kunit::kunit_case_null(), // ]; //
@@ -106,7 +106,7 @@ pub(crate) fn kunit_tests(attr: TokenStream, ts: TokenStream) -> TokenStream { writeln!(kunit_macros, "{kunit_wrapper}").unwrap(); writeln!( test_cases, - " kernel::kunit::kunit_case(kernel::c_str!(\"{test}\"), {kunit_wrapper_fn_name})," + " kernel::kunit::kunit_case(c\"{test}\", {kunit_wrapper_fn_name}),", ) .unwrap(); }
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 44e5cb108cea..7b71d6d99d5c 100644
--- a/rust/macros/module.rs
+++ b/rust/macros/module.rs@@ -232,7 +232,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { type LocalModule = {type_}; impl kernel::ModuleMetadata for {type_} {{ - const NAME: &'static kernel::str::CStr = kernel::c_str!(\"{name}\"); + const NAME: &'static kernel::str::CStr = c\"{name}\"; }} // Double nested modules, since then nobody can access the public items inside.
diff --git a/samples/rust/rust_driver_faux.rs b/samples/rust/rust_driver_faux.rs
index ecc9fd378cbd..23add3160693 100644
--- a/samples/rust/rust_driver_faux.rs
+++ b/samples/rust/rust_driver_faux.rs@@ -2,7 +2,7 @@ //! Rust faux device sample. -use kernel::{c_str, faux, prelude::*, Module}; +use kernel::{faux, prelude::*, Module}; module! { type: SampleModule,
@@ -20,7 +20,7 @@ impl Module for SampleModule { fn init(_module: &'static ThisModule) -> Result<Self> { pr_info!("Initialising Rust Faux Device Sample\n"); - let reg = faux::Registration::new(c_str!("rust-faux-sample-device"), None)?; + let reg = faux::Registration::new(c"rust-faux-sample-device", None)?; dev_info!(reg.as_ref(), "Hello from faux device!\n");
diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs
index 2bb260aebc9e..8da48c1c3c2d 100644
--- a/samples/rust/rust_driver_pci.rs
+++ b/samples/rust/rust_driver_pci.rs@@ -4,7 +4,7 @@ //! //! To make this driver probe, QEMU must be run with `-device pci-testdev`. -use kernel::{bindings, c_str, device::Core, devres::Devres, pci, prelude::*, types::ARef}; +use kernel::{bindings, device::Core, devres::Devres, pci, prelude::*, types::ARef}; struct Regs;
@@ -73,7 +73,7 @@ fn probe(pdev: &pci::Device<Core>, info: &Self::IdInfo) -> Result<Pin<KBox<Self> pdev.enable_device_mem()?; pdev.set_master(); - let bar = pdev.iomap_region_sized::<{ Regs::END }>(0, c_str!("rust_driver_pci"))?; + let bar = pdev.iomap_region_sized::<{ Regs::END }>(0, c"rust_driver_pci")?; let drvdata = KBox::new( Self {
diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs
index 8b42b3cfb363..e6487a970a59 100644
--- a/samples/rust/rust_driver_platform.rs
+++ b/samples/rust/rust_driver_platform.rs@@ -2,7 +2,7 @@ //! Rust Platform driver sample. -use kernel::{c_str, device::Core, of, platform, prelude::*, types::ARef}; +use kernel::{device::Core, of, platform, prelude::*, types::ARef}; struct SampleDriver { pdev: ARef<platform::Device>,
@@ -14,7 +14,7 @@ struct SampleDriver { OF_TABLE, MODULE_OF_TABLE, <SampleDriver as platform::Driver>::IdInfo, - [(of::DeviceId::new(c_str!("test,rust-device")), Info(42))] + [(of::DeviceId::new(c"test,rust-device"), Info(42))] ); impl platform::Driver for SampleDriver {
diff --git a/samples/rust/rust_misc_device.rs b/samples/rust/rust_misc_device.rs
index c881fd6dbd08..12b64296e912 100644
--- a/samples/rust/rust_misc_device.rs
+++ b/samples/rust/rust_misc_device.rs@@ -98,7 +98,6 @@ use core::pin::Pin; use kernel::{ - c_str, device::Device, fs::File, ioctl::{_IO, _IOC_SIZE, _IOR, _IOW},
@@ -133,7 +132,7 @@ fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> { pr_info!("Initialising Rust Misc Device Sample\n"); let options = MiscDeviceOptions { - name: c_str!("rust-misc-device"), + name: c"rust-misc-device", }; try_pin_init!(Self {
--
2.49.0