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/*
 * Copyright (c) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup sparc64proc
 * @{
 */
/** @file
 */

#include <proc/scheduler.h>
#include <proc/thread.h>
#include <arch.h>
#include <arch/asm.h>
#include <arch/stack.h>

/** Perform sparc64 specific tasks needed before the new task is run. */
void before_task_runs_arch(void)
{
}

/** Perform sparc64 specific steps before scheduling a thread.
 *
 * For userspace threads, initialize reserved global registers in the alternate
 * and interrupt sets.
 */
void before_thread_runs_arch(void)
{
    if ((THREAD->flags & THREAD_FLAG_USPACE)) {
        /*
         * Write kernel stack address to %g6 of the alternate and
         * interrupt global sets.
         *
         * Write pointer to the last item in the userspace window buffer
         * to %g7 in the alternate set. Write to the interrupt %g7 is
         * not necessary because:
         * - spill traps operate only in the alternate global set,
         * - preemptible trap handler switches to alternate globals
         *   before it explicitly uses %g7.
         */
        uint64_t sp = (uintptr_t) THREAD->kstack + STACK_SIZE -
            (STACK_BIAS + ALIGN_UP(STACK_ITEM_SIZE, STACK_ALIGNMENT));
        write_to_ig_g6(sp);
        write_to_ag_g6(sp);
        write_to_ag_g7((uintptr_t) THREAD->arch.uspace_window_buffer);
    }
}

/** Perform sparc64 specific steps before a thread stops running. */
void after_thread_ran_arch(void)
{
    if ((THREAD->flags & THREAD_FLAG_USPACE)) {
        /* sample the state of the userspace window buffer */   
        THREAD->arch.uspace_window_buffer = (uint8_t *) read_from_ag_g7();
    }
}

/** @}
 */