Fix cpu_freq for Apple silicon (#2222)

Apple SoC returns empty string after querying the cpu frequency using
sysctl, this information however, can still be extracted from the IOKit
registry. This PR adds a new method that is specific to Apple ARM
architecture.

Signed-off-by: Oliver T <geronimooliver00@gmail.com>

CREDITS

@@ -813,3 +813,7 @@ I: 2156, 2345
 N: Lawrence D'Anna
 W: https://github.com/smoofra
 I: 2010
+
+N: Oliver Tomé
+W: https://github.com/snom3ad
+I: 2222

HISTORY.rst

@@ -20,6 +20,8 @@
 - 2340_, [NetBSD]: if process is terminated, `Process.cwd()`_ will return an
   empty string instead of raising `NoSuchProcess`_.
 - 2345_, [Linux]: fix compilation on older compiler missing DUPLEX_UNKNOWN
+- 2222_, [macOS]: `cpu_freq()` now returns fixed values for `min` and `max`
+  frequencies in all Apple Silicon chips.
 
 5.9.7
 =====

psutil/arch/osx/cpu.c

@@ -26,6 +26,10 @@ For reference, here's the git history with original implementations:
 #include <sys/sysctl.h>
 #include <sys/vmmeter.h>
 #include <mach/mach.h>
+#if defined(__arm64__) || defined(__aarch64__)
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+#endif
 
 #include "../../_psutil_common.h"
 #include "../../_psutil_posix.h"
@@ -109,7 +113,122 @@ psutil_cpu_stats(PyObject *self, PyObject *args) {
     );
 }
 
+#if defined(__arm64__) || defined(__aarch64__)
+PyObject *
+psutil_cpu_freq(PyObject *self, PyObject *args) {
+    uint32_t min;
+    uint32_t curr;
+    uint32_t pMin;
+    uint32_t eMin;
+    uint32_t max;
+    kern_return_t status;
+    CFDictionaryRef matching = NULL;
+    CFTypeRef pCoreRef = NULL;
+    CFTypeRef eCoreRef = NULL;
+    io_iterator_t iter = 0;
+    io_registry_entry_t entry = 0;
+    io_name_t name;
+
+    matching = IOServiceMatching("AppleARMIODevice");
+    if (matching == 0) {
+        return PyErr_Format(
+            PyExc_RuntimeError,
+            "IOServiceMatching call failed, 'AppleARMIODevice' not found"
+        );
+    }
+
+    status = IOServiceGetMatchingServices(kIOMainPortDefault, matching, &iter);
+    if (status != KERN_SUCCESS) {
+        PyErr_Format(
+            PyExc_RuntimeError, "IOServiceGetMatchingServices call failed"
+        );
+        goto error;
+    }
+
+    while ((entry = IOIteratorNext(iter)) != 0) {
+        status = IORegistryEntryGetName(entry, name);
+        if (status != KERN_SUCCESS) {
+            IOObjectRelease(entry);
+            continue;
+        }
+        if (strcmp(name, "pmgr") == 0) {
+            break;
+        }
+        IOObjectRelease(entry);
+    }
 
+    if (entry == 0) {
+        PyErr_Format(
+            PyExc_RuntimeError,
+            "'pmgr' entry was not found in AppleARMIODevice service"
+        );
+        goto error;
+    }
+
+    pCoreRef = IORegistryEntryCreateCFProperty(
+        entry, CFSTR("voltage-states5-sram"), kCFAllocatorDefault, 0);
+    if (pCoreRef == NULL) {
+        PyErr_Format(
+            PyExc_RuntimeError, "'voltage-states5-sram' property not found");
+        goto error;
+    }
+
+    eCoreRef = IORegistryEntryCreateCFProperty(
+        entry, CFSTR("voltage-states1-sram"), kCFAllocatorDefault, 0);
+    if (eCoreRef == NULL) {
+        PyErr_Format(
+            PyExc_RuntimeError, "'voltage-states1-sram' property not found");
+        goto error;
+    }
+
+    size_t pCoreLength = CFDataGetLength(pCoreRef);
+    size_t eCoreLength = CFDataGetLength(eCoreRef);
+    if (pCoreLength < 8) {
+        PyErr_Format(
+            PyExc_RuntimeError,
+            "expected 'voltage-states5-sram' buffer to have at least size 8"
+        );
+        goto error;
+    }
+    if (eCoreLength < 4) {
+        PyErr_Format(
+            PyExc_RuntimeError,
+            "expected 'voltage-states1-sram' buffer to have at least size 4"
+        );
+        goto error;
+    }
+
+    CFDataGetBytes(pCoreRef, CFRangeMake(0, 4), (UInt8 *) &pMin);
+    CFDataGetBytes(eCoreRef, CFRangeMake(0, 4), (UInt8 *) &eMin);
+    CFDataGetBytes(pCoreRef, CFRangeMake(pCoreLength - 8, 4), (UInt8 *) &max);
+
+    min = pMin < eMin ? pMin : eMin;
+    curr = max;
+
+    CFRelease(pCoreRef);
+    CFRelease(eCoreRef);
+    IOObjectRelease(iter);
+    IOObjectRelease(entry);
+
+    return Py_BuildValue(
+        "IKK",
+        curr / 1000 / 1000,
+        min / 1000 / 1000,
+        max / 1000 / 1000
+    );
+
+error:
+    if (pCoreRef != NULL)
+        CFRelease(pCoreRef);
+    if (eCoreRef != NULL)
+        CFRelease(eCoreRef);
+    if (iter != 0)
+        IOObjectRelease(iter);
+    if (entry != 0)
+        IOObjectRelease(entry);
+    return NULL;
+}
+#else
 PyObject *
 psutil_cpu_freq(PyObject *self, PyObject *args) {
     unsigned int curr;
@@ -138,7 +257,7 @@ psutil_cpu_freq(PyObject *self, PyObject *args) {
         min / 1000 / 1000,
         max / 1000 / 1000);
 }
-
+#endif
 
 PyObject *
 psutil_per_cpu_times(PyObject *self, PyObject *args) {