Index: head/sys/dev/acpica/acpi.c
===================================================================
--- head/sys/dev/acpica/acpi.c
+++ head/sys/dev/acpica/acpi.c
@@ -2480,6 +2480,29 @@
     return (AE_OK);
 }
 
+ACPI_STATUS
+acpi_EvaluateOSC(ACPI_HANDLE handle, uint8_t *uuid, int revision, int count,
+    uint32_t *caps, bool query)
+{
+	ACPI_OBJECT arg[4];
+	ACPI_OBJECT_LIST arglist;
+
+	arglist.Pointer = arg;
+	arglist.Count = 4;
+	arg[0].Type = ACPI_TYPE_BUFFER;
+	arg[0].Buffer.Length = ACPI_UUID_LENGTH;
+	arg[0].Buffer.Pointer = uuid;
+	arg[1].Type = ACPI_TYPE_INTEGER;
+	arg[1].Integer.Value = revision;
+	arg[2].Type = ACPI_TYPE_INTEGER;
+	arg[2].Integer.Value = count;
+	arg[3].Type = ACPI_TYPE_BUFFER;
+	arg[3].Buffer.Length = count * sizeof(uint32_t);
+	arg[3].Buffer.Pointer = (uint8_t *)caps;
+	caps[0] = query ? 1 : 0;
+	return (AcpiEvaluateObject(handle, "_OSC", &arglist, NULL));
+}
+
 /*
  * Set interrupt model.
  */
Index: head/sys/dev/acpica/acpi_cpu.c
===================================================================
--- head/sys/dev/acpica/acpi_cpu.c
+++ head/sys/dev/acpica/acpi_cpu.c
@@ -296,7 +296,7 @@
 acpi_cpu_attach(device_t dev)
 {
     ACPI_BUFFER		   buf;
-    ACPI_OBJECT		   arg[4], *obj;
+    ACPI_OBJECT		   arg[1], *obj;
     ACPI_OBJECT_LIST	   arglist;
     struct pcpu		   *pcpu_data;
     struct acpi_cpu_softc *sc;
@@ -391,21 +391,9 @@
      * Intel Processor Vendor-Specific ACPI Interface Specification.
      */
     if (sc->cpu_features) {
-	arglist.Pointer = arg;
-	arglist.Count = 4;
-	arg[0].Type = ACPI_TYPE_BUFFER;
-	arg[0].Buffer.Length = sizeof(cpu_oscuuid);
-	arg[0].Buffer.Pointer = cpu_oscuuid;	/* UUID */
-	arg[1].Type = ACPI_TYPE_INTEGER;
-	arg[1].Integer.Value = 1;		/* revision */
-	arg[2].Type = ACPI_TYPE_INTEGER;
-	arg[2].Integer.Value = 1;		/* count */
-	arg[3].Type = ACPI_TYPE_BUFFER;
-	arg[3].Buffer.Length = sizeof(cap_set);	/* Capabilities buffer */
-	arg[3].Buffer.Pointer = (uint8_t *)cap_set;
-	cap_set[0] = 0;				/* status */
 	cap_set[1] = sc->cpu_features;
-	status = AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
+	status = acpi_EvaluateOSC(sc->cpu_handle, cpu_oscuuid, 1, 2, cap_set,
+	    false);
 	if (ACPI_SUCCESS(status)) {
 	    if (cap_set[0] != 0)
 		device_printf(dev, "_OSC returned status %#x\n", cap_set[0]);
Index: head/sys/dev/acpica/acpivar.h
===================================================================
--- head/sys/dev/acpica/acpivar.h
+++ head/sys/dev/acpica/acpivar.h
@@ -335,6 +335,8 @@
 		    ACPI_RESOURCE **resp);
 ACPI_STATUS	acpi_AppendBufferResource(ACPI_BUFFER *buf,
 		    ACPI_RESOURCE *res);
+ACPI_STATUS	acpi_EvaluateOSC(ACPI_HANDLE handle, uint8_t *uuid,
+		    int revision, int count, uint32_t *caps, bool query);
 ACPI_STATUS	acpi_OverrideInterruptLevel(UINT32 InterruptNumber);
 ACPI_STATUS	acpi_SetIntrModel(int model);
 int		acpi_ReqSleepState(struct acpi_softc *sc, int state);