src/sys/prof/idletask.C


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/*  IBM_PROLOG_BEGIN_TAG
 *  This is an automatically generated prolog.
 *
 *  $Source: src/sys/prof/idletask.C $
 *
 *  IBM CONFIDENTIAL
 *
 *  COPYRIGHT International Business Machines Corp. 2012
 *
 *  p1
 *
 *  Object Code Only (OCO) source materials
 *  Licensed Internal Code Source Materials
 *  IBM HostBoot Licensed Internal Code
 *
 *  The source code for this program is not published or other-
 *  wise divested of its trade secrets, irrespective of what has
 *  been deposited with the U.S. Copyright Office.
 *
 *  Origin: 30
 *
 *  IBM_PROLOG_END_TAG
 */
/** @file idletask.C
 *  @brief Code for the kernel idle-loop.
 *
 *  This code exists here under the sys/prof directory to ensure that it does
 *  not get instrumented with code coverage.  The idle threads run stack-less
 *  and bad things happen if they have been instrumented.
 */

#include <kernel/taskmgr.H>
#include <arch/ppc.H>
#include <sys/syscall.h>

using namespace Systemcalls;

void* TaskManager::idleTaskLoop(void* unused)
{
    while(1)
    {
	// Lower priority (and yield simics thread).
        setThreadPriorityLow();

        // Request privilege escalation for nap.
        asm volatile("li 3, %0; sc" :: "K" (MISC_CPUNAP) : "r3", "cc");

        // Execute nap.
        nap();
    }
   return NULL;
}