Merge branch 'pm-cpufreq'

Merge Rust support for cpufreq and OPP, a new Rust-based cpufreq-dt
driver, an SCMI cpufreq driver cleanup, and an ACPI cpufreq driver
regression fix:

 - Add Rust abstractions for CPUFreq framework (Viresh Kumar).

 - Add Rust abstractions for OPP framework (Viresh Kumar).

 - Add basic Rust abstractions for Clk and Cpumask frameworks (Viresh
   Kumar).

 - Clean up the SCMI cpufreq driver somewhat (Mike Tipton).

 - Use KHz as the nominal_freq units in get_max_boost_ratio() in the
   ACPI cpufreq driver (iGautham Shenoy).

* pm-cpufreq:
  acpi-cpufreq: Fix nominal_freq units to KHz in get_max_boost_ratio()
  rust: opp: Move `cfg(CONFIG_OF)` attribute to the top of doc test
  rust: opp: Make the doctest example depend on CONFIG_OF
  cpufreq: scmi: Skip SCMI devices that aren't used by the CPUs
  cpufreq: Add Rust-based cpufreq-dt driver
  rust: opp: Extend OPP abstractions with cpufreq support
  rust: cpufreq: Extend abstractions for driver registration
  rust: cpufreq: Extend abstractions for policy and driver ops
  rust: cpufreq: Add initial abstractions for cpufreq framework
  rust: opp: Add abstractions for the configuration options
  rust: opp: Add abstractions for the OPP table
  rust: opp: Add initial abstractions for OPP framework
  rust: cpu: Add from_cpu()
  rust: macros: enable use of hyphens in module names
  rust: clk: Add initial abstractions
  rust: clk: Add helpers for Rust code
  MAINTAINERS: Add entry for Rust cpumask API
  rust: cpumask: Add initial abstractions
  rust: cpumask: Add few more helpers

MAINTAINERS

@@ -5949,6 +5949,8 @@ F:	include/dt-bindings/clock/
 F:	include/linux/clk-pr*
 F:	include/linux/clk/
 F:	include/linux/of_clk.h
+F:	rust/helpers/clk.c
+F:	rust/kernel/clk.rs
 X:	drivers/clk/clkdev.c
 
 COMMON INTERNET FILE SYSTEM CLIENT (CIFS and SMB3)
@@ -6208,6 +6210,7 @@ F:	drivers/cpufreq/
 F:	include/linux/cpufreq.h
 F:	include/linux/sched/cpufreq.h
 F:	kernel/sched/cpufreq*.c
+F:	rust/kernel/cpufreq.rs
 F:	tools/testing/selftests/cpufreq/
 
 CPU HOTPLUG
@@ -6221,6 +6224,7 @@ F:	include/linux/cpuhotplug.h
 F:	include/linux/smpboot.h
 F:	kernel/cpu.c
 F:	kernel/smpboot.*
+F:	rust/kernel/cpu.rs
 
 CPU IDLE TIME MANAGEMENT FRAMEWORK
 M:	"Rafael J. Wysocki" <rafael@kernel.org>
@@ -6305,6 +6309,12 @@ L:	linux-riscv@lists.infradead.org
 S:	Maintained
 F:	drivers/cpuidle/cpuidle-riscv-sbi.c
 
+CPUMASK API [RUST]
+M:	Viresh Kumar <viresh.kumar@linaro.org>
+R:	Yury Norov <yury.norov@gmail.com>
+S:	Maintained
+F:	rust/kernel/cpumask.rs
+
 CRAMFS FILESYSTEM
 M:	Nicolas Pitre <nico@fluxnic.net>
 S:	Maintained
@@ -18504,6 +18514,7 @@ F:	Documentation/devicetree/bindings/opp/
 F:	Documentation/power/opp.rst
 F:	drivers/opp/
 F:	include/linux/pm_opp.h
+F:	rust/kernel/opp.rs
 
 OPL4 DRIVER
 M:	Clemens Ladisch <clemens@ladisch.de>

drivers/cpufreq/Kconfig

@@ -217,6 +217,18 @@ config CPUFREQ_DT
 
 	  If in doubt, say N.
 
+config CPUFREQ_DT_RUST
+	tristate "Rust based Generic DT based cpufreq driver"
+	depends on HAVE_CLK && OF && RUST
+	select CPUFREQ_DT_PLATDEV
+	select PM_OPP
+	help
+	  This adds a Rust based generic DT based cpufreq driver for frequency
+	  management.  It supports both uniprocessor (UP) and symmetric
+	  multiprocessor (SMP) systems.
+
+	  If in doubt, say N.
+
 config CPUFREQ_VIRT
 	tristate "Virtual cpufreq driver"
 	depends on GENERIC_ARCH_TOPOLOGY

drivers/cpufreq/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_COMMON)		+= cpufreq_governor.o
 obj-$(CONFIG_CPU_FREQ_GOV_ATTR_SET)	+= cpufreq_governor_attr_set.o
 
 obj-$(CONFIG_CPUFREQ_DT)		+= cpufreq-dt.o
+obj-$(CONFIG_CPUFREQ_DT_RUST)		+= rcpufreq_dt.o
 obj-$(CONFIG_CPUFREQ_DT_PLATDEV)	+= cpufreq-dt-platdev.o
 obj-$(CONFIG_CPUFREQ_VIRT)		+= virtual-cpufreq.o
 

drivers/cpufreq/acpi-cpufreq.c

@@ -660,7 +660,7 @@ static u64 get_max_boost_ratio(unsigned int cpu, u64 *nominal_freq)
 	nominal_perf = perf_caps.nominal_perf;
 
 	if (nominal_freq)
-		*nominal_freq = perf_caps.nominal_freq;
+		*nominal_freq = perf_caps.nominal_freq * 1000;
 
 	if (!highest_perf || !nominal_perf) {
 		pr_debug("CPU%d: highest or nominal performance missing\n", cpu);

drivers/cpufreq/rcpufreq_dt.rs

@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust based implementation of the cpufreq-dt driver.
+
+use kernel::{
+    c_str,
+    clk::Clk,
+    cpu, cpufreq,
+    cpumask::CpumaskVar,
+    device::{Core, Device},
+    error::code::*,
+    fmt,
+    macros::vtable,
+    module_platform_driver, of, opp, platform,
+    prelude::*,
+    str::CString,
+    sync::Arc,
+};
+
+/// Finds exact supply name from the OF node.
+fn find_supply_name_exact(dev: &Device, name: &str) -> Option<CString> {
+    let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?;
+    dev.property_present(&prop_name)
+        .then(|| CString::try_from_fmt(fmt!("{name}")).ok())
+        .flatten()
+}
+
+/// Finds supply name for the CPU from DT.
+fn find_supply_names(dev: &Device, cpu: u32) -> Option<KVec<CString>> {
+    // Try "cpu0" for older DTs, fallback to "cpu".
+    let name = (cpu == 0)
+        .then(|| find_supply_name_exact(dev, "cpu0"))
+        .flatten()
+        .or_else(|| find_supply_name_exact(dev, "cpu"))?;
+
+    let mut list = KVec::with_capacity(1, GFP_KERNEL).ok()?;
+    list.push(name, GFP_KERNEL).ok()?;
+
+    Some(list)
+}
+
+/// Represents the cpufreq dt device.
+struct CPUFreqDTDevice {
+    opp_table: opp::Table,
+    freq_table: opp::FreqTable,
+    _mask: CpumaskVar,
+    _token: Option<opp::ConfigToken>,
+    _clk: Clk,
+}
+
+#[derive(Default)]
+struct CPUFreqDTDriver;
+
+#[vtable]
+impl opp::ConfigOps for CPUFreqDTDriver {}
+
+#[vtable]
+impl cpufreq::Driver for CPUFreqDTDriver {
+    const NAME: &'static CStr = c_str!("cpufreq-dt");
+    const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV;
+    const BOOST_ENABLED: bool = true;
+
+    type PData = Arc<CPUFreqDTDevice>;
+
+    fn init(policy: &mut cpufreq::Policy) -> Result<Self::PData> {
+        let cpu = policy.cpu();
+        // SAFETY: The CPU device is only used during init; it won't get hot-unplugged. The cpufreq
+        // core  registers with CPU notifiers and the cpufreq core/driver won't use the CPU device,
+        // once the CPU is hot-unplugged.
+        let dev = unsafe { cpu::from_cpu(cpu)? };
+        let mut mask = CpumaskVar::new_zero(GFP_KERNEL)?;
+
+        mask.set(cpu);
+
+        let token = find_supply_names(dev, cpu)
+            .map(|names| {
+                opp::Config::<Self>::new()
+                    .set_regulator_names(names)?
+                    .set(dev)
+            })
+            .transpose()?;
+
+        // Get OPP-sharing information from "operating-points-v2" bindings.
+        let fallback = match opp::Table::of_sharing_cpus(dev, &mut mask) {
+            Ok(()) => false,
+            Err(e) if e == ENOENT => {
+                // "operating-points-v2" not supported. If the platform hasn't
+                // set sharing CPUs, fallback to all CPUs share the `Policy`
+                // for backward compatibility.
+                opp::Table::sharing_cpus(dev, &mut mask).is_err()
+            }
+            Err(e) => return Err(e),
+        };
+
+        // Initialize OPP tables for all policy cpus.
+        //
+        // For platforms not using "operating-points-v2" bindings, we do this
+        // before updating policy cpus. Otherwise, we will end up creating
+        // duplicate OPPs for the CPUs.
+        //
+        // OPPs might be populated at runtime, don't fail for error here unless
+        // it is -EPROBE_DEFER.
+        let mut opp_table = match opp::Table::from_of_cpumask(dev, &mut mask) {
+            Ok(table) => table,
+            Err(e) => {
+                if e == EPROBE_DEFER {
+                    return Err(e);
+                }
+
+                // The table is added dynamically ?
+                opp::Table::from_dev(dev)?
+            }
+        };
+
+        // The OPP table must be initialized, statically or dynamically, by this point.
+        opp_table.opp_count()?;
+
+        // Set sharing cpus for fallback scenario.
+        if fallback {
+            mask.setall();
+            opp_table.set_sharing_cpus(&mut mask)?;
+        }
+
+        let mut transition_latency = opp_table.max_transition_latency_ns() as u32;
+        if transition_latency == 0 {
+            transition_latency = cpufreq::ETERNAL_LATENCY_NS;
+        }
+
+        policy
+            .set_dvfs_possible_from_any_cpu(true)
+            .set_suspend_freq(opp_table.suspend_freq())
+            .set_transition_latency_ns(transition_latency);
+
+        let freq_table = opp_table.cpufreq_table()?;
+        // SAFETY: The `freq_table` is not dropped while it is getting used by the C code.
+        unsafe { policy.set_freq_table(&freq_table) };
+
+        // SAFETY: The returned `clk` is not dropped while it is getting used by the C code.
+        let clk = unsafe { policy.set_clk(dev, None)? };
+
+        mask.copy(policy.cpus());
+
+        Ok(Arc::new(
+            CPUFreqDTDevice {
+                opp_table,
+                freq_table,
+                _mask: mask,
+                _token: token,
+                _clk: clk,
+            },
+            GFP_KERNEL,
+        )?)
+    }
+
+    fn exit(_policy: &mut cpufreq::Policy, _data: Option<Self::PData>) -> Result {
+        Ok(())
+    }
+
+    fn online(_policy: &mut cpufreq::Policy) -> Result {
+        // We did light-weight tear down earlier, nothing to do here.
+        Ok(())
+    }
+
+    fn offline(_policy: &mut cpufreq::Policy) -> Result {
+        // Preserve policy->data and don't free resources on light-weight
+        // tear down.
+        Ok(())
+    }
+
+    fn suspend(policy: &mut cpufreq::Policy) -> Result {
+        policy.generic_suspend()
+    }
+
+    fn verify(data: &mut cpufreq::PolicyData) -> Result {
+        data.generic_verify()
+    }
+
+    fn target_index(policy: &mut cpufreq::Policy, index: cpufreq::TableIndex) -> Result {
+        let Some(data) = policy.data::<Self::PData>() else {
+            return Err(ENOENT);
+        };
+
+        let freq = data.freq_table.freq(index)?;
+        data.opp_table.set_rate(freq)
+    }
+
+    fn get(policy: &mut cpufreq::Policy) -> Result<u32> {
+        policy.generic_get()
+    }
+
+    fn set_boost(_policy: &mut cpufreq::Policy, _state: i32) -> Result {
+        Ok(())
+    }
+
+    fn register_em(policy: &mut cpufreq::Policy) {
+        policy.register_em_opp()
+    }
+}
+
+kernel::of_device_table!(
+    OF_TABLE,
+    MODULE_OF_TABLE,
+    <CPUFreqDTDriver as platform::Driver>::IdInfo,
+    [(of::DeviceId::new(c_str!("operating-points-v2")), ())]
+);
+
+impl platform::Driver for CPUFreqDTDriver {
+    type IdInfo = ();
+    const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+
+    fn probe(
+        pdev: &platform::Device<Core>,
+        _id_info: Option<&Self::IdInfo>,
+    ) -> Result<Pin<KBox<Self>>> {
+        cpufreq::Registration::<CPUFreqDTDriver>::new_foreign_owned(pdev.as_ref())?;
+        Ok(KBox::new(Self {}, GFP_KERNEL)?.into())
+    }
+}
+
+module_platform_driver! {
+    type: CPUFreqDTDriver,
+    name: "cpufreq-dt",
+    author: "Viresh Kumar <viresh.kumar@linaro.org>",
+    description: "Generic CPUFreq DT driver",
+    license: "GPL v2",
+}

drivers/cpufreq/scmi-cpufreq.c

@@ -393,6 +393,40 @@ static struct cpufreq_driver scmi_cpufreq_driver = {
 	.set_boost	= cpufreq_boost_set_sw,
 };
 
+static bool scmi_dev_used_by_cpus(struct device *scmi_dev)
+{
+	struct device_node *scmi_np = dev_of_node(scmi_dev);
+	struct device_node *cpu_np, *np;
+	struct device *cpu_dev;
+	int cpu, idx;
+
+	if (!scmi_np)
+		return false;
+
+	for_each_possible_cpu(cpu) {
+		cpu_dev = get_cpu_device(cpu);
+		if (!cpu_dev)
+			continue;
+
+		cpu_np = dev_of_node(cpu_dev);
+
+		np = of_parse_phandle(cpu_np, "clocks", 0);
+		of_node_put(np);
+
+		if (np == scmi_np)
+			return true;
+
+		idx = of_property_match_string(cpu_np, "power-domain-names", "perf");
+		np = of_parse_phandle(cpu_np, "power-domains", idx);
+		of_node_put(np);
+
+		if (np == scmi_np)
+			return true;
+	}
+
+	return false;
+}
+
 static int scmi_cpufreq_probe(struct scmi_device *sdev)
 {
 	int ret;
@@ -401,7 +435,7 @@ static int scmi_cpufreq_probe(struct scmi_device *sdev)
 
 	handle = sdev->handle;
 
-	if (!handle)
+	if (!handle || !scmi_dev_used_by_cpus(dev))
 		return -ENODEV;
 
 	scmi_cpufreq_driver.driver_data = sdev;

rust/bindings/bindings_helper.h

@@ -16,7 +16,10 @@
 #include <linux/blk-mq.h>
 #include <linux/blk_types.h>
 #include <linux/blkdev.h>
+#include <linux/clk.h>
 #include <linux/configfs.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/cred.h>
 #include <linux/device/faux.h>
@@ -35,6 +38,7 @@
 #include <linux/phy.h>
 #include <linux/pid_namespace.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/poll.h>
 #include <linux/property.h>
 #include <linux/refcount.h>

rust/helpers/clk.c

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/clk.h>
+
+/*
+ * The "inline" implementation of below helpers are only available when
+ * CONFIG_HAVE_CLK or CONFIG_HAVE_CLK_PREPARE aren't set.
+ */
+#ifndef CONFIG_HAVE_CLK
+struct clk *rust_helper_clk_get(struct device *dev, const char *id)
+{
+	return clk_get(dev, id);
+}
+
+void rust_helper_clk_put(struct clk *clk)
+{
+	clk_put(clk);
+}
+
+int rust_helper_clk_enable(struct clk *clk)
+{
+	return clk_enable(clk);
+}
+
+void rust_helper_clk_disable(struct clk *clk)
+{
+	clk_disable(clk);
+}
+
+unsigned long rust_helper_clk_get_rate(struct clk *clk)
+{
+	return clk_get_rate(clk);
+}
+
+int rust_helper_clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	return clk_set_rate(clk, rate);
+}
+#endif
+
+#ifndef CONFIG_HAVE_CLK_PREPARE
+int rust_helper_clk_prepare(struct clk *clk)
+{
+	return clk_prepare(clk);
+}
+
+void rust_helper_clk_unprepare(struct clk *clk)
+{
+	clk_unprepare(clk);
+}
+#endif
+
+struct clk *rust_helper_clk_get_optional(struct device *dev, const char *id)
+{
+	return clk_get_optional(dev, id);
+}
+
+int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+	return clk_prepare_enable(clk);
+}
+
+void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+	clk_disable_unprepare(clk);
+}

rust/helpers/cpufreq.c

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/cpufreq.h>
+
+#ifdef CONFIG_CPU_FREQ
+void rust_helper_cpufreq_register_em_with_opp(struct cpufreq_policy *policy)
+{
+	cpufreq_register_em_with_opp(policy);
+}
+#endif

rust/helpers/cpumask.c

@@ -7,16 +7,41 @@ void rust_helper_cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
 	cpumask_set_cpu(cpu, dstp);
 }
 
+void rust_helper___cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
+{
+	__cpumask_set_cpu(cpu, dstp);
+}
+
 void rust_helper_cpumask_clear_cpu(int cpu, struct cpumask *dstp)
 {
 	cpumask_clear_cpu(cpu, dstp);
 }
 
+void rust_helper___cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+{
+	__cpumask_clear_cpu(cpu, dstp);
+}
+
+bool rust_helper_cpumask_test_cpu(int cpu, struct cpumask *srcp)
+{
+	return cpumask_test_cpu(cpu, srcp);
+}
+
 void rust_helper_cpumask_setall(struct cpumask *dstp)
 {
 	cpumask_setall(dstp);
 }
 
+bool rust_helper_cpumask_empty(struct cpumask *srcp)
+{
+	return cpumask_empty(srcp);
+}
+
+bool rust_helper_cpumask_full(struct cpumask *srcp)
+{
+	return cpumask_full(srcp);
+}
+
 unsigned int rust_helper_cpumask_weight(struct cpumask *srcp)
 {
 	return cpumask_weight(srcp);

rust/helpers/helpers.c

@@ -12,6 +12,8 @@
 #include "bug.c"
 #include "build_assert.c"
 #include "build_bug.c"
+#include "clk.c"
+#include "cpufreq.c"
 #include "cpumask.c"
 #include "cred.c"
 #include "device.c"

rust/kernel/clk.rs

@@ -0,0 +1,334 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Clock abstractions.
+//!
+//! C header: [`include/linux/clk.h`](srctree/include/linux/clk.h)
+//!
+//! Reference: <https://docs.kernel.org/driver-api/clk.html>
+
+use crate::ffi::c_ulong;
+
+/// The frequency unit.
+///
+/// Represents a frequency in hertz, wrapping a [`c_ulong`] value.
+///
+/// ## Examples
+///
+/// ```
+/// use kernel::clk::Hertz;
+///
+/// let hz = 1_000_000_000;
+/// let rate = Hertz(hz);
+///
+/// assert_eq!(rate.as_hz(), hz);
+/// assert_eq!(rate, Hertz(hz));
+/// assert_eq!(rate, Hertz::from_khz(hz / 1_000));
+/// assert_eq!(rate, Hertz::from_mhz(hz / 1_000_000));
+/// assert_eq!(rate, Hertz::from_ghz(hz / 1_000_000_000));
+/// ```
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct Hertz(pub c_ulong);
+
+impl Hertz {
+    /// Create a new instance from kilohertz (kHz)
+    pub fn from_khz(khz: c_ulong) -> Self {
+        Self(khz * 1_000)
+    }
+
+    /// Create a new instance from megahertz (MHz)
+    pub fn from_mhz(mhz: c_ulong) -> Self {
+        Self(mhz * 1_000_000)
+    }
+
+    /// Create a new instance from gigahertz (GHz)
+    pub fn from_ghz(ghz: c_ulong) -> Self {
+        Self(ghz * 1_000_000_000)
+    }
+
+    /// Get the frequency in hertz
+    pub fn as_hz(&self) -> c_ulong {
+        self.0
+    }
+
+    /// Get the frequency in kilohertz
+    pub fn as_khz(&self) -> c_ulong {
+        self.0 / 1_000
+    }
+
+    /// Get the frequency in megahertz
+    pub fn as_mhz(&self) -> c_ulong {
+        self.0 / 1_000_000
+    }
+
+    /// Get the frequency in gigahertz
+    pub fn as_ghz(&self) -> c_ulong {
+        self.0 / 1_000_000_000
+    }
+}
+
+impl From<Hertz> for c_ulong {
+    fn from(freq: Hertz) -> Self {
+        freq.0
+    }
+}
+
+#[cfg(CONFIG_COMMON_CLK)]
+mod common_clk {
+    use super::Hertz;
+    use crate::{
+        device::Device,
+        error::{from_err_ptr, to_result, Result},
+        prelude::*,
+    };
+
+    use core::{ops::Deref, ptr};
+
+    /// A reference-counted clock.
+    ///
+    /// Rust abstraction for the C [`struct clk`].
+    ///
+    /// # Invariants
+    ///
+    /// A [`Clk`] instance holds either a pointer to a valid [`struct clk`] created by the C
+    /// portion of the kernel or a NULL pointer.
+    ///
+    /// Instances of this type are reference-counted. Calling [`Clk::get`] ensures that the
+    /// allocation remains valid for the lifetime of the [`Clk`].
+    ///
+    /// ## Examples
+    ///
+    /// The following example demonstrates how to obtain and configure a clock for a device.
+    ///
+    /// ```
+    /// use kernel::c_str;
+    /// use kernel::clk::{Clk, Hertz};
+    /// use kernel::device::Device;
+    /// use kernel::error::Result;
+    ///
+    /// fn configure_clk(dev: &Device) -> Result {
+    ///     let clk = Clk::get(dev, Some(c_str!("apb_clk")))?;
+    ///
+    ///     clk.prepare_enable()?;
+    ///
+    ///     let expected_rate = Hertz::from_ghz(1);
+    ///
+    ///     if clk.rate() != expected_rate {
+    ///         clk.set_rate(expected_rate)?;
+    ///     }
+    ///
+    ///     clk.disable_unprepare();
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// [`struct clk`]: https://docs.kernel.org/driver-api/clk.html
+    #[repr(transparent)]
+    pub struct Clk(*mut bindings::clk);
+
+    impl Clk {
+        /// Gets [`Clk`] corresponding to a [`Device`] and a connection id.
+        ///
+        /// Equivalent to the kernel's [`clk_get`] API.
+        ///
+        /// [`clk_get`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_get
+        pub fn get(dev: &Device, name: Option<&CStr>) -> Result<Self> {
+            let con_id = if let Some(name) = name {
+                name.as_ptr()
+            } else {
+                ptr::null()
+            };
+
+            // SAFETY: It is safe to call [`clk_get`] for a valid device pointer.
+            //
+            // INVARIANT: The reference-count is decremented when [`Clk`] goes out of scope.
+            Ok(Self(from_err_ptr(unsafe {
+                bindings::clk_get(dev.as_raw(), con_id)
+            })?))
+        }
+
+        /// Obtain the raw [`struct clk`] pointer.
+        #[inline]
+        pub fn as_raw(&self) -> *mut bindings::clk {
+            self.0
+        }
+
+        /// Enable the clock.
+        ///
+        /// Equivalent to the kernel's [`clk_enable`] API.
+        ///
+        /// [`clk_enable`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_enable
+        #[inline]
+        pub fn enable(&self) -> Result {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_enable`].
+            to_result(unsafe { bindings::clk_enable(self.as_raw()) })
+        }
+
+        /// Disable the clock.
+        ///
+        /// Equivalent to the kernel's [`clk_disable`] API.
+        ///
+        /// [`clk_disable`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_disable
+        #[inline]
+        pub fn disable(&self) {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_disable`].
+            unsafe { bindings::clk_disable(self.as_raw()) };
+        }
+
+        /// Prepare the clock.
+        ///
+        /// Equivalent to the kernel's [`clk_prepare`] API.
+        ///
+        /// [`clk_prepare`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_prepare
+        #[inline]
+        pub fn prepare(&self) -> Result {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_prepare`].
+            to_result(unsafe { bindings::clk_prepare(self.as_raw()) })
+        }
+
+        /// Unprepare the clock.
+        ///
+        /// Equivalent to the kernel's [`clk_unprepare`] API.
+        ///
+        /// [`clk_unprepare`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_unprepare
+        #[inline]
+        pub fn unprepare(&self) {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_unprepare`].
+            unsafe { bindings::clk_unprepare(self.as_raw()) };
+        }
+
+        /// Prepare and enable the clock.
+        ///
+        /// Equivalent to calling [`Clk::prepare`] followed by [`Clk::enable`].
+        #[inline]
+        pub fn prepare_enable(&self) -> Result {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_prepare_enable`].
+            to_result(unsafe { bindings::clk_prepare_enable(self.as_raw()) })
+        }
+
+        /// Disable and unprepare the clock.
+        ///
+        /// Equivalent to calling [`Clk::disable`] followed by [`Clk::unprepare`].
+        #[inline]
+        pub fn disable_unprepare(&self) {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_disable_unprepare`].
+            unsafe { bindings::clk_disable_unprepare(self.as_raw()) };
+        }
+
+        /// Get clock's rate.
+        ///
+        /// Equivalent to the kernel's [`clk_get_rate`] API.
+        ///
+        /// [`clk_get_rate`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_get_rate
+        #[inline]
+        pub fn rate(&self) -> Hertz {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_get_rate`].
+            Hertz(unsafe { bindings::clk_get_rate(self.as_raw()) })
+        }
+
+        /// Set clock's rate.
+        ///
+        /// Equivalent to the kernel's [`clk_set_rate`] API.
+        ///
+        /// [`clk_set_rate`]: https://docs.kernel.org/core-api/kernel-api.html#c.clk_set_rate
+        #[inline]
+        pub fn set_rate(&self, rate: Hertz) -> Result {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for
+            // [`clk_set_rate`].
+            to_result(unsafe { bindings::clk_set_rate(self.as_raw(), rate.as_hz()) })
+        }
+    }
+
+    impl Drop for Clk {
+        fn drop(&mut self) {
+            // SAFETY: By the type invariants, self.as_raw() is a valid argument for [`clk_put`].
+            unsafe { bindings::clk_put(self.as_raw()) };
+        }
+    }
+
+    /// A reference-counted optional clock.
+    ///
+    /// A lightweight wrapper around an optional [`Clk`]. An [`OptionalClk`] represents a [`Clk`]
+    /// that a driver can function without but may improve performance or enable additional
+    /// features when available.
+    ///
+    /// # Invariants
+    ///
+    /// An [`OptionalClk`] instance encapsulates a [`Clk`] with either a valid [`struct clk`] or
+    /// `NULL` pointer.
+    ///
+    /// Instances of this type are reference-counted. Calling [`OptionalClk::get`] ensures that the
+    /// allocation remains valid for the lifetime of the [`OptionalClk`].
+    ///
+    /// ## Examples
+    ///
+    /// The following example demonstrates how to obtain and configure an optional clock for a
+    /// device. The code functions correctly whether or not the clock is available.
+    ///
+    /// ```
+    /// use kernel::c_str;
+    /// use kernel::clk::{OptionalClk, Hertz};
+    /// use kernel::device::Device;
+    /// use kernel::error::Result;
+    ///
+    /// fn configure_clk(dev: &Device) -> Result {
+    ///     let clk = OptionalClk::get(dev, Some(c_str!("apb_clk")))?;
+    ///
+    ///     clk.prepare_enable()?;
+    ///
+    ///     let expected_rate = Hertz::from_ghz(1);
+    ///
+    ///     if clk.rate() != expected_rate {
+    ///         clk.set_rate(expected_rate)?;
+    ///     }
+    ///
+    ///     clk.disable_unprepare();
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// [`struct clk`]: https://docs.kernel.org/driver-api/clk.html
+    pub struct OptionalClk(Clk);
+
+    impl OptionalClk {
+        /// Gets [`OptionalClk`] corresponding to a [`Device`] and a connection id.
+        ///
+        /// Equivalent to the kernel's [`clk_get_optional`] API.
+        ///
+        /// [`clk_get_optional`]:
+        /// https://docs.kernel.org/core-api/kernel-api.html#c.clk_get_optional
+        pub fn get(dev: &Device, name: Option<&CStr>) -> Result<Self> {
+            let con_id = if let Some(name) = name {
+                name.as_ptr()
+            } else {
+                ptr::null()
+            };
+
+            // SAFETY: It is safe to call [`clk_get_optional`] for a valid device pointer.
+            //
+            // INVARIANT: The reference-count is decremented when [`OptionalClk`] goes out of
+            // scope.
+            Ok(Self(Clk(from_err_ptr(unsafe {
+                bindings::clk_get_optional(dev.as_raw(), con_id)
+            })?)))
+        }
+    }
+
+    // Make [`OptionalClk`] behave like [`Clk`].
+    impl Deref for OptionalClk {
+        type Target = Clk;
+
+        fn deref(&self) -> &Clk {
+            &self.0
+        }
+    }
+}
+
+#[cfg(CONFIG_COMMON_CLK)]
+pub use common_clk::*;

rust/kernel/cpu.rs

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic CPU definitions.
+//!
+//! C header: [`include/linux/cpu.h`](srctree/include/linux/cpu.h)
+
+use crate::{bindings, device::Device, error::Result, prelude::ENODEV};
+
+/// Creates a new instance of CPU's device.
+///
+/// # Safety
+///
+/// Reference counting is not implemented for the CPU device in the C code. When a CPU is
+/// hot-unplugged, the corresponding CPU device is unregistered, but its associated memory
+/// is not freed.
+///
+/// Callers must ensure that the CPU device is not used after it has been unregistered.
+/// This can be achieved, for example, by registering a CPU hotplug notifier and removing
+/// any references to the CPU device within the notifier's callback.
+pub unsafe fn from_cpu(cpu: u32) -> Result<&'static Device> {
+    // SAFETY: It is safe to call `get_cpu_device()` for any CPU.
+    let ptr = unsafe { bindings::get_cpu_device(cpu) };
+    if ptr.is_null() {
+        return Err(ENODEV);
+    }
+
+    // SAFETY: The pointer returned by `get_cpu_device()`, if not `NULL`, is a valid pointer to
+    // a `struct device` and is never freed by the C code.
+    Ok(unsafe { Device::as_ref(ptr) })
+}

rust/kernel/cpumask.rs

@@ -0,0 +1,330 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! CPU Mask abstractions.
+//!
+//! C header: [`include/linux/cpumask.h`](srctree/include/linux/cpumask.h)
+
+use crate::{
+    alloc::{AllocError, Flags},
+    prelude::*,
+    types::Opaque,
+};
+
+#[cfg(CONFIG_CPUMASK_OFFSTACK)]
+use core::ptr::{self, NonNull};
+
+#[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+use core::mem::MaybeUninit;
+
+use core::ops::{Deref, DerefMut};
+
+/// A CPU Mask.
+///
+/// Rust abstraction for the C `struct cpumask`.
+///
+/// # Invariants
+///
+/// A [`Cpumask`] instance always corresponds to a valid C `struct cpumask`.
+///
+/// The callers must ensure that the `struct cpumask` is valid for access and
+/// remains valid for the lifetime of the returned reference.
+///
+/// ## Examples
+///
+/// The following example demonstrates how to update a [`Cpumask`].
+///
+/// ```
+/// use kernel::bindings;
+/// use kernel::cpumask::Cpumask;
+///
+/// fn set_clear_cpu(ptr: *mut bindings::cpumask, set_cpu: u32, clear_cpu: i32) {
+///     // SAFETY: The `ptr` is valid for writing and remains valid for the lifetime of the
+///     // returned reference.
+///     let mask = unsafe { Cpumask::as_mut_ref(ptr) };
+///
+///     mask.set(set_cpu);
+///     mask.clear(clear_cpu);
+/// }
+/// ```
+#[repr(transparent)]
+pub struct Cpumask(Opaque<bindings::cpumask>);
+
+impl Cpumask {
+    /// Creates a mutable reference to an existing `struct cpumask` pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime
+    /// of the returned reference.
+    pub unsafe fn as_mut_ref<'a>(ptr: *mut bindings::cpumask) -> &'a mut Self {
+        // SAFETY: Guaranteed by the safety requirements of the function.
+        //
+        // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the
+        // lifetime of the returned reference.
+        unsafe { &mut *ptr.cast() }
+    }
+
+    /// Creates a reference to an existing `struct cpumask` pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime
+    /// of the returned reference.
+    pub unsafe fn as_ref<'a>(ptr: *const bindings::cpumask) -> &'a Self {
+        // SAFETY: Guaranteed by the safety requirements of the function.
+        //
+        // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the
+        // lifetime of the returned reference.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Obtain the raw `struct cpumask` pointer.
+    pub fn as_raw(&self) -> *mut bindings::cpumask {
+        let this: *const Self = self;
+        this.cast_mut().cast()
+    }
+
+    /// Set `cpu` in the cpumask.
+    ///
+    /// ATTENTION: Contrary to C, this Rust `set()` method is non-atomic.
+    /// This mismatches kernel naming convention and corresponds to the C
+    /// function `__cpumask_set_cpu()`.
+    #[inline]
+    pub fn set(&mut self, cpu: u32) {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `__cpumask_set_cpu`.
+        unsafe { bindings::__cpumask_set_cpu(cpu, self.as_raw()) };
+    }
+
+    /// Clear `cpu` in the cpumask.
+    ///
+    /// ATTENTION: Contrary to C, this Rust `clear()` method is non-atomic.
+    /// This mismatches kernel naming convention and corresponds to the C
+    /// function `__cpumask_clear_cpu()`.
+    #[inline]
+    pub fn clear(&mut self, cpu: i32) {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to
+        // `__cpumask_clear_cpu`.
+        unsafe { bindings::__cpumask_clear_cpu(cpu, self.as_raw()) };
+    }
+
+    /// Test `cpu` in the cpumask.
+    ///
+    /// Equivalent to the kernel's `cpumask_test_cpu` API.
+    #[inline]
+    pub fn test(&self, cpu: i32) -> bool {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_test_cpu`.
+        unsafe { bindings::cpumask_test_cpu(cpu, self.as_raw()) }
+    }
+
+    /// Set all CPUs in the cpumask.
+    ///
+    /// Equivalent to the kernel's `cpumask_setall` API.
+    #[inline]
+    pub fn setall(&mut self) {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_setall`.
+        unsafe { bindings::cpumask_setall(self.as_raw()) };
+    }
+
+    /// Checks if cpumask is empty.
+    ///
+    /// Equivalent to the kernel's `cpumask_empty` API.
+    #[inline]
+    pub fn empty(&self) -> bool {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_empty`.
+        unsafe { bindings::cpumask_empty(self.as_raw()) }
+    }
+
+    /// Checks if cpumask is full.
+    ///
+    /// Equivalent to the kernel's `cpumask_full` API.
+    #[inline]
+    pub fn full(&self) -> bool {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_full`.
+        unsafe { bindings::cpumask_full(self.as_raw()) }
+    }
+
+    /// Get weight of the cpumask.
+    ///
+    /// Equivalent to the kernel's `cpumask_weight` API.
+    #[inline]
+    pub fn weight(&self) -> u32 {
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `cpumask_weight`.
+        unsafe { bindings::cpumask_weight(self.as_raw()) }
+    }
+
+    /// Copy cpumask.
+    ///
+    /// Equivalent to the kernel's `cpumask_copy` API.
+    #[inline]
+    pub fn copy(&self, dstp: &mut Self) {
+        // SAFETY: By the type invariant, `Self::as_raw` is a valid argument to `cpumask_copy`.
+        unsafe { bindings::cpumask_copy(dstp.as_raw(), self.as_raw()) };
+    }
+}
+
+/// A CPU Mask pointer.
+///
+/// Rust abstraction for the C `struct cpumask_var_t`.
+///
+/// # Invariants
+///
+/// A [`CpumaskVar`] instance always corresponds to a valid C `struct cpumask_var_t`.
+///
+/// The callers must ensure that the `struct cpumask_var_t` is valid for access and remains valid
+/// for the lifetime of [`CpumaskVar`].
+///
+/// ## Examples
+///
+/// The following example demonstrates how to create and update a [`CpumaskVar`].
+///
+/// ```
+/// use kernel::cpumask::CpumaskVar;
+///
+/// let mut mask = CpumaskVar::new_zero(GFP_KERNEL).unwrap();
+///
+/// assert!(mask.empty());
+/// mask.set(2);
+/// assert!(mask.test(2));
+/// mask.set(3);
+/// assert!(mask.test(3));
+/// assert_eq!(mask.weight(), 2);
+///
+/// let mask2 = CpumaskVar::try_clone(&mask).unwrap();
+/// assert!(mask2.test(2));
+/// assert!(mask2.test(3));
+/// assert_eq!(mask2.weight(), 2);
+/// ```
+pub struct CpumaskVar {
+    #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+    ptr: NonNull<Cpumask>,
+    #[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+    mask: Cpumask,
+}
+
+impl CpumaskVar {
+    /// Creates a zero-initialized instance of the [`CpumaskVar`].
+    pub fn new_zero(_flags: Flags) -> Result<Self, AllocError> {
+        Ok(Self {
+            #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+            ptr: {
+                let mut ptr: *mut bindings::cpumask = ptr::null_mut();
+
+                // SAFETY: It is safe to call this method as the reference to `ptr` is valid.
+                //
+                // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of
+                // scope.
+                unsafe { bindings::zalloc_cpumask_var(&mut ptr, _flags.as_raw()) };
+                NonNull::new(ptr.cast()).ok_or(AllocError)?
+            },
+
+            #[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+            // SAFETY: FFI type is valid to be zero-initialized.
+            //
+            // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of scope.
+            mask: unsafe { core::mem::zeroed() },
+        })
+    }
+
+    /// Creates an instance of the [`CpumaskVar`].
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that the returned [`CpumaskVar`] is properly initialized before
+    /// getting used.
+    pub unsafe fn new(_flags: Flags) -> Result<Self, AllocError> {
+        Ok(Self {
+            #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+            ptr: {
+                let mut ptr: *mut bindings::cpumask = ptr::null_mut();
+
+                // SAFETY: It is safe to call this method as the reference to `ptr` is valid.
+                //
+                // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of
+                // scope.
+                unsafe { bindings::alloc_cpumask_var(&mut ptr, _flags.as_raw()) };
+                NonNull::new(ptr.cast()).ok_or(AllocError)?
+            },
+            #[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+            // SAFETY: Guaranteed by the safety requirements of the function.
+            //
+            // INVARIANT: The associated memory is freed when the `CpumaskVar` goes out of scope.
+            mask: unsafe { MaybeUninit::uninit().assume_init() },
+        })
+    }
+
+    /// Creates a mutable reference to an existing `struct cpumask_var_t` pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid for writing and remains valid for the lifetime
+    /// of the returned reference.
+    pub unsafe fn as_mut_ref<'a>(ptr: *mut bindings::cpumask_var_t) -> &'a mut Self {
+        // SAFETY: Guaranteed by the safety requirements of the function.
+        //
+        // INVARIANT: The caller ensures that `ptr` is valid for writing and remains valid for the
+        // lifetime of the returned reference.
+        unsafe { &mut *ptr.cast() }
+    }
+
+    /// Creates a reference to an existing `struct cpumask_var_t` pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid for reading and remains valid for the lifetime
+    /// of the returned reference.
+    pub unsafe fn as_ref<'a>(ptr: *const bindings::cpumask_var_t) -> &'a Self {
+        // SAFETY: Guaranteed by the safety requirements of the function.
+        //
+        // INVARIANT: The caller ensures that `ptr` is valid for reading and remains valid for the
+        // lifetime of the returned reference.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Clones cpumask.
+    pub fn try_clone(cpumask: &Cpumask) -> Result<Self> {
+        // SAFETY: The returned cpumask_var is initialized right after this call.
+        let mut cpumask_var = unsafe { Self::new(GFP_KERNEL) }?;
+
+        cpumask.copy(&mut cpumask_var);
+        Ok(cpumask_var)
+    }
+}
+
+// Make [`CpumaskVar`] behave like a pointer to [`Cpumask`].
+impl Deref for CpumaskVar {
+    type Target = Cpumask;
+
+    #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The caller owns CpumaskVar, so it is safe to deref the cpumask.
+        unsafe { &*self.ptr.as_ptr() }
+    }
+
+    #[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+    fn deref(&self) -> &Self::Target {
+        &self.mask
+    }
+}
+
+impl DerefMut for CpumaskVar {
+    #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+    fn deref_mut(&mut self) -> &mut Cpumask {
+        // SAFETY: The caller owns CpumaskVar, so it is safe to deref the cpumask.
+        unsafe { self.ptr.as_mut() }
+    }
+
+    #[cfg(not(CONFIG_CPUMASK_OFFSTACK))]
+    fn deref_mut(&mut self) -> &mut Cpumask {
+        &mut self.mask
+    }
+}
+
+impl Drop for CpumaskVar {
+    fn drop(&mut self) {
+        #[cfg(CONFIG_CPUMASK_OFFSTACK)]
+        // SAFETY: By the type invariant, `self.as_raw` is a valid argument to `free_cpumask_var`.
+        unsafe {
+            bindings::free_cpumask_var(self.as_raw())
+        };
+    }
+}

rust/kernel/lib.rs

@@ -44,8 +44,13 @@ pub mod auxiliary;
 pub mod block;
 #[doc(hidden)]
 pub mod build_assert;
+pub mod clk;
 #[cfg(CONFIG_CONFIGFS_FS)]
 pub mod configfs;
+pub mod cpu;
+#[cfg(CONFIG_CPU_FREQ)]
+pub mod cpufreq;
+pub mod cpumask;
 pub mod cred;
 pub mod device;
 pub mod device_id;
@@ -70,6 +75,8 @@ pub mod miscdevice;
 #[cfg(CONFIG_NET)]
 pub mod net;
 pub mod of;
+#[cfg(CONFIG_PM_OPP)]
+pub mod opp;
 pub mod page;
 #[cfg(CONFIG_PCI)]
 pub mod pci;

rust/macros/module.rs

@@ -176,7 +176,9 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
 
     let info = ModuleInfo::parse(&mut it);
 
-    let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
+    // Rust does not allow hyphens in identifiers, use underscore instead.
+    let ident = info.name.replace('-', "_");
+    let mut modinfo = ModInfoBuilder::new(ident.as_ref());
     if let Some(author) = info.author {
         modinfo.emit("author", &author);
     }
@@ -301,14 +303,15 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[doc(hidden)]
                     #[link_section = \"{initcall_section}\"]
                     #[used]
-                    pub static __{name}_initcall: extern \"C\" fn() -> kernel::ffi::c_int = __{name}_init;
+                    pub static __{ident}_initcall: extern \"C\" fn() ->
+                        kernel::ffi::c_int = __{ident}_init;
 
                     #[cfg(not(MODULE))]
                     #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
                     core::arch::global_asm!(
                         r#\".section \"{initcall_section}\", \"a\"
-                        __{name}_initcall:
-                            .long   __{name}_init - .
+                        __{ident}_initcall:
+                            .long   __{ident}_init - .
                             .previous
                         \"#
                     );
@@ -316,7 +319,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[cfg(not(MODULE))]
                     #[doc(hidden)]
                     #[no_mangle]
-                    pub extern \"C\" fn __{name}_init() -> kernel::ffi::c_int {{
+                    pub extern \"C\" fn __{ident}_init() -> kernel::ffi::c_int {{
                         // SAFETY: This function is inaccessible to the outside due to the double
                         // module wrapping it. It is called exactly once by the C side via its
                         // placement above in the initcall section.
@@ -326,13 +329,13 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
                     #[cfg(not(MODULE))]
                     #[doc(hidden)]
                     #[no_mangle]
-                    pub extern \"C\" fn __{name}_exit() {{
+                    pub extern \"C\" fn __{ident}_exit() {{
                         // SAFETY:
                         // - This function is inaccessible to the outside due to the double
                         //   module wrapping it. It is called exactly once by the C side via its
                         //   unique name,
-                        // - furthermore it is only called after `__{name}_init` has returned `0`
-                        //   (which delegates to `__init`).
+                        // - furthermore it is only called after `__{ident}_init` has
+                        //   returned `0` (which delegates to `__init`).
                         unsafe {{ __exit() }}
                     }}
 
@@ -372,6 +375,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
         ",
         type_ = info.type_,
         name = info.name,
+        ident = ident,
         modinfo = modinfo.buffer,
         initcall_section = ".initcall6.init"
     )