101 lines
3.6 KiB
C
101 lines
3.6 KiB
C
/****************************************************************************
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* arch/x86/src/i486/up_savestate.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 <assert.h>
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#include <debug.h>
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#include <arch/arch.h>
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#include <arch/irq.h>
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#include "up_internal.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_savestate
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*
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* Description:
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* This function saves the interrupt level context information in the
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* TCB. This would just be a up_copystate but we have to handle one
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* special case. In the case where the privilege level changes, the
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* value of sp and ss will not be saved on stack by the interrupt handler.
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* So, in that case, we will have to fudge those values here.
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*
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****************************************************************************/
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void up_savestate(uint32_t *regs)
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{
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uint8_t cpl;
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uint8_t rpl;
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/* First, just copy all of the registers */
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up_copystate(regs, (uint32_t *)g_current_regs);
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/* The RES_SP and REG_SS values will not be saved by the interrupt handling
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* logic if there is no change in privilege level. In that case, we will
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* have to "fudge" those values here. For now, just overwrite the REG_SP
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* and REG_SS values with what we believe to be correct. Obviously, this
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* will have to change in the future to support multi-segment operation.
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*
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* Check for a change in privilege level.
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*/
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rpl = regs[REG_CS] & 3;
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cpl = up_getcs() & 3;
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DEBUGASSERT(rpl >= cpl);
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if (rpl == cpl)
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{
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/* No priority change, SP and SS are not present in the stack frame.
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*
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* The value saved in the REG_ESP will be the stackpointer value prior
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* to the execution of the PUSHA. It will point at REG_IRQNO.
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*/
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regs[REG_SP] = g_current_regs[REG_ESP] + 4*BOTTOM_NOPRIO;
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regs[REG_SS] = up_getss();
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}
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else
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{
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DEBUGASSERT(regs[REG_SP] == g_current_regs[REG_ESP] + 4*BOTTOM_PRIO);
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}
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}
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