[PATCH v4 2/9] rust: cpumask: Add getters for globally defined cpumasks

[Mitchell Levy <levymitchell0@gmail.com>]

Add getters for the global cpumasks documented in
`include/linux/cpumask.h`, specifically:
- cpu_possible_mask
- cpu_online_mask
- cpu_enabled_mask
- cpu_present_mask
- cpu_active_mask

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
---
 rust/kernel/cpumask.rs | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/rust/kernel/cpumask.rs b/rust/kernel/cpumask.rs
index b7401848f59e..a6a130092fcb 100644
--- a/rust/kernel/cpumask.rs
+++ b/rust/kernel/cpumask.rs
@@ -77,6 +77,52 @@ pub unsafe fn as_ref<'a>(ptr: *const bindings::cpumask) -> &'a Self {
         unsafe { &*ptr.cast() }
     }
 
+    /// Get a CPU mask representing possible CPUs; has bit `cpu` set iff cpu is populatable
+    #[inline]
+    pub fn possible_cpus() -> &'static Self {
+        // SAFETY: `__cpu_possible_mask` is a valid global provided by the kernel that lives
+        // forever.
+        unsafe { Cpumask::as_ref(&raw const bindings::__cpu_possible_mask) }
+    }
+
+    /// Get a CPU mask representing online CPUs; has bit `cpu` set iff cpu available to the
+    /// scheduler
+    #[inline]
+    pub fn online_cpus() -> &'static Self {
+        // SAFETY: `__cpu_online_mask` is a valid global provided by the kernel that lives forever.
+        // Since we wrap the returned pointer in an `Opaque`, it's ok that `__cpu_online_mask`
+        // may change its value.
+        unsafe { Cpumask::as_ref(&raw const bindings::__cpu_online_mask) }
+    }
+
+    /// Get a CPU mask representing enabled CPUs; has bit `cpu` set iff cpu can be brought online
+    #[inline]
+    pub fn enabled_cpus() -> &'static Self {
+        // SAFETY: `__cpu_enabled_mask` is a valid global provided by the kernel that lives forever.
+        // Since we wrap the returned pointer in an `Opaque`, it's ok that `__cpu_enabled_mask`
+        // may change its value.
+        unsafe { Cpumask::as_ref(&raw const bindings::__cpu_enabled_mask) }
+    }
+
+    /// Get a CPU mask representing present CPUs; has bit `cpu` set iff cpu is populated
+    #[inline]
+    pub fn present_cpus() -> &'static Self {
+        // SAFETY: `__cpu_present_mask` is a valid global provided by the kernel that lives
+        // forever. Since we wrap the returned pointer in an `Opaque`, it's ok that
+        // `__cpu_present_mask` may change its value.
+        unsafe { Cpumask::as_ref(&raw const bindings::__cpu_present_mask) }
+    }
+
+    /// Get a CPU mask representing active CPUs; has bit `cpu` set iff cpu is available to
+    /// migration.
+    #[inline]
+    pub fn active_cpus() -> &'static Self {
+        // SAFETY: `__cpu_active_mask` is a valid global provided by the kernel that lives forever.
+        // Since we wrap the returned pointer in an `Opaque`, it's ok that `__cpu_active_mask`
+        // may change its value.
+        unsafe { Cpumask::as_ref(&raw const bindings::__cpu_active_mask) }
+    }
+
     /// Obtain the raw `struct cpumask` pointer.
     pub fn as_raw(&self) -> *mut bindings::cpumask {
         let this: *const Self = self;

-- 
2.34.1