Kernel: Move feature string building to ProcessorInfo

Other than a dmesgln(), ProcessorInfo is the only user of this function
and is already responsible for building other CPUID-related strings.

Author: linusg

Kernel/Arch/x86/Processor.h

@@ -128,8 +128,6 @@ class Processor {
     void cpu_detect();
     void cpu_setup();
 
-    NonnullOwnPtr<KString> features_string() const;
-
 public:
     Processor() = default;
 

Kernel/Arch/x86/ProcessorInfo.h

@@ -22,6 +22,7 @@ class ProcessorInfo {
 
     static NonnullOwnPtr<KString> build_vendor_id_string();
     static NonnullOwnPtr<KString> build_brand_string();
+    static NonnullOwnPtr<KString> build_features_string(Processor const&);
 
     StringView vendor_id_string() const { return m_vendor_id_string->view(); }
     StringView brand_string() const { return m_brand_string->view(); }

Kernel/Arch/x86/common/Processor.cpp

@@ -596,22 +596,6 @@ UNMAP_AFTER_INIT void Processor::cpu_setup()
 #endif
 }
 
-NonnullOwnPtr<KString> Processor::features_string() const
-{
-    StringBuilder builder;
-    bool first = true;
-    for (auto feature = CPUFeature::Type(1u); feature != CPUFeature::__End; feature <<= 1u) {
-        if (has_feature(feature)) {
-            if (first)
-                first = false;
-            else
-                MUST(builder.try_append(' '));
-            MUST(builder.try_append(cpu_feature_to_string_view(feature)));
-        }
-    }
-    return KString::must_create(builder.string_view());
-}
-
 UNMAP_AFTER_INIT void Processor::early_initialize(u32 cpu)
 {
     m_self = this;
@@ -651,7 +635,9 @@ UNMAP_AFTER_INIT void Processor::initialize(u32 cpu)
     VERIFY(m_self == this);
     VERIFY(&current() == this); // sanity check
 
-    dmesgln("CPU[{}]: Supported features: {}", current_id(), features_string());
+    m_info = new ProcessorInfo(*this);
+
+    dmesgln("CPU[{}]: Supported features: {}", current_id(), m_info->features_string());
     if (!has_feature(CPUFeature::RDRAND))
         dmesgln("CPU[{}]: No RDRAND support detected, randomness will be poor", current_id());
     dmesgln("CPU[{}]: Physical address bit width: {}", current_id(), m_physical_address_bit_width);
@@ -680,8 +666,6 @@ UNMAP_AFTER_INIT void Processor::initialize(u32 cpu)
             detect_hypervisor();
     }
 
-    m_info = new ProcessorInfo(*this);
-
     {
         // We need to prevent races between APs starting up at the same time
         VERIFY(cpu < s_processors.size());

Kernel/Arch/x86/common/ProcessorInfo.cpp

@@ -15,7 +15,7 @@ namespace Kernel {
 ProcessorInfo::ProcessorInfo(Processor const& processor)
     : m_vendor_id_string(build_vendor_id_string())
     , m_brand_string(build_brand_string())
-    , m_features_string(processor.features_string())
+    , m_features_string(build_features_string(processor))
 {
     CPUID cpuid(1);
     m_stepping = cpuid.eax() & 0xf;
@@ -75,4 +75,20 @@ NonnullOwnPtr<KString> ProcessorInfo::build_brand_string()
     return KString::must_create(buffer);
 }
 
+NonnullOwnPtr<KString> ProcessorInfo::build_features_string(Processor const& processor)
+{
+    StringBuilder builder;
+    bool first = true;
+    for (auto feature = CPUFeature::Type(1u); feature != CPUFeature::__End; feature <<= 1u) {
+        if (processor.has_feature(feature)) {
+            if (first)
+                first = false;
+            else
+                MUST(builder.try_append(' '));
+            MUST(builder.try_append(cpu_feature_to_string_view(feature)));
+        }
+    }
+    return KString::must_create(builder.string_view());
+}
+
 }