114 lines
3.6 KiB
C
114 lines
3.6 KiB
C
/****************************************************************************
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* arch/x86_64/src/common/x86_64_switchcontext.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sched.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/sched.h>
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#include <stdio.h>
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#include "sched/sched.h"
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#include "group/group.h"
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#include "clock/clock.h"
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#include "x86_64_internal.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_switch_context
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*
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* Description:
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* A task is currently in the ready-to-run list but has been prepped
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* to execute. Restore its context, and start execution.
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*
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* Input Parameters:
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* tcb: Refers to the head task of the ready-to-run list
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* which will be executed.
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* rtcb: Refers to the running task which will be blocked.
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*
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****************************************************************************/
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void up_switch_context(struct tcb_s *tcb, struct tcb_s *rtcb)
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{
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/* Update scheduler parameters */
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nxsched_suspend_scheduler(rtcb);
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/* Are we in an interrupt handler? */
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if (g_current_regs)
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{
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/* Yes, then we have to do things differently.
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* Just copy the g_current_regs into the OLD rtcb.
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*/
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x86_64_savestate(rtcb->xcp.regs);
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x86_64_restore_auxstate(tcb);
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/* Update scheduler parameters */
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nxsched_resume_scheduler(tcb);
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/* Then switch contexts. Any necessary address environment
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* changes will be made when the interrupt returns.
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*/
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x86_64_restorestate(tcb->xcp.regs);
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}
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/* We are not in an interrupt handler. Copy the user C context
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* into the TCB of the task that was previously active. if
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* up_saveusercontext returns a non-zero value, then this is really the
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* previously running task restarting!
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*/
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else if (!up_saveusercontext(rtcb->xcp.regs))
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{
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x86_64_restore_auxstate(tcb);
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#ifdef CONFIG_ARCH_ADDRENV
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/* Make sure that the address environment for the previously
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* running task is closed down gracefully (data caches dump,
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* MMU flushed) and set up the address environment for the new
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* thread at the head of the ready-to-run list.
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*/
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group_addrenv(tcb);
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#endif
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/* Update scheduler parameters */
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nxsched_resume_scheduler(tcb);
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/* Then switch contexts */
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x86_64_fullcontextrestore(tcb->xcp.regs);
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}
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}
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