feat: HWP scaling, C1E, closed-loop thermal governor for Intel CPUs

kernel/src/Api/Power.hpp

@@ -12,6 +12,8 @@
 #include <Graphics/Framebuffer.hpp>
 #include <ACPI/AcpiShutdown.hpp>
 #include <ACPI/AcpiSleep.hpp>
+#include <ACPI/CpuIdle.hpp>
+#include <Hal/CpuPower.hpp>
 
 #include "Syscall.hpp"
 
@@ -71,4 +73,27 @@ namespace montauk::abi {
         }
         return (int64_t)Hal::AcpiSleep::Suspend();
     }
+
+    // SYS_POWERINFO. Fills a CPU power/thermal snapshot. Returns -1 when the
+    // CPU exposes no power management features (e.g. under QEMU).
+    static int64_t Sys_PowerInfo(PowerInfo* out) {
+        Hal::CpuPower::Snapshot s{};
+        if (!Hal::CpuPower::GetSnapshot(s)) {
+            return -1;
+        }
+
+        out->hwpActive   = s.HwpActive ? 1 : 0;
+        out->throttling  = s.Throttling ? 1 : 0;
+        out->tempC       = s.TempC;
+        out->tjMaxC      = s.TjMaxC;
+        out->highestPerf = s.HighestPerf;
+        out->lowestPerf  = s.LowestPerf;
+        out->curMaxPerf  = s.CurMaxPerf;
+        out->epp         = s.Epp;
+        out->baseMHz     = s.BaseMHz;
+        out->maxMHz      = s.MaxMHz;
+        out->effMHz      = s.EffMHz;
+        out->apIdleHint  = Hal::CpuIdle::GetApIdleHint();
+        return 0;
+    }
 };