isa.cc revision 8059 
1/*
2 * Copyright (c) 2009 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Gabe Black
29 */
30
31#include "arch/x86/isa.hh"
32#include "arch/x86/tlb.hh"
33#include "cpu/base.hh"
34#include "cpu/thread_context.hh"
35#include "sim/serialize.hh"
36
37namespace X86ISA
38{
39
40void
41ISA::updateHandyM5Reg(Efer efer, CR0 cr0,
42                      SegAttr csAttr, SegAttr ssAttr, RFLAGS rflags)
43{
44    HandyM5Reg m5reg = 0;
45    if (efer.lma) {
46        m5reg.mode = LongMode;
47        if (csAttr.longMode)
48            m5reg.submode = SixtyFourBitMode;
49        else
50            m5reg.submode = CompatabilityMode;
51    } else {
52        m5reg.mode = LegacyMode;
53        if (cr0.pe) {
54            if (rflags.vm)
55                m5reg.submode = Virtual8086Mode;
56            else
57                m5reg.submode = ProtectedMode;
58        } else {
59            m5reg.submode = RealMode;
60        }
61    }
62    m5reg.cpl = csAttr.dpl;
63    m5reg.paging = cr0.pg;
64    m5reg.prot = cr0.pe;
65
66    // Compute the default and alternate operand size.
67    if (m5reg.submode == SixtyFourBitMode || csAttr.defaultSize) {
68        m5reg.defOp = 2;
69        m5reg.altOp = 1;
70    } else {
71        m5reg.defOp = 1;
72        m5reg.altOp = 2;
73    }
74
75    // Compute the default and alternate address size.
76    if (m5reg.submode == SixtyFourBitMode) {
77        m5reg.defAddr = 3;
78        m5reg.altAddr = 2;
79    } else if (csAttr.defaultSize) {
80        m5reg.defAddr = 2;
81        m5reg.altAddr = 1;
82    } else {
83        m5reg.defAddr = 1;
84        m5reg.altAddr = 2;
85    }
86
87    // Compute the stack size
88    if (m5reg.submode == SixtyFourBitMode) {
89        m5reg.stack = 3;
90    } else if (ssAttr.defaultSize) {
91        m5reg.stack = 2;
92    } else {
93        m5reg.stack = 1;
94    }
95
96    regVal[MISCREG_M5_REG] = m5reg;
97}
98
99void
100ISA::clear()
101{
102    // Blank everything. 0 might not be an appropriate value for some things,
103    // but it is for most.
104    memset(regVal, 0, NumMiscRegs * sizeof(MiscReg));
105    regVal[MISCREG_DR6] = (mask(8) << 4) | (mask(16) << 16);
106    regVal[MISCREG_DR7] = 1 << 10;
107}
108
109MiscReg
110ISA::readMiscRegNoEffect(int miscReg)
111{
112    // Make sure we're not dealing with an illegal control register.
113    // Instructions should filter out these indexes, and nothing else should
114    // attempt to read them directly.
115    assert( miscReg != MISCREG_CR1 &&
116            !(miscReg > MISCREG_CR4 &&
117              miscReg < MISCREG_CR8) &&
118            !(miscReg > MISCREG_CR8 &&
119              miscReg <= MISCREG_CR15));
120
121    return regVal[miscReg];
122}
123
124MiscReg
125ISA::readMiscReg(int miscReg, ThreadContext * tc)
126{
127    if (miscReg == MISCREG_TSC) {
128        return regVal[MISCREG_TSC] + tc->getCpuPtr()->curCycle();
129    }
130    return readMiscRegNoEffect(miscReg);
131}
132
133void
134ISA::setMiscRegNoEffect(int miscReg, MiscReg val)
135{
136    // Make sure we're not dealing with an illegal control register.
137    // Instructions should filter out these indexes, and nothing else should
138    // attempt to write to them directly.
139    assert( miscReg != MISCREG_CR1 &&
140            !(miscReg > MISCREG_CR4 &&
141              miscReg < MISCREG_CR8) &&
142            !(miscReg > MISCREG_CR8 &&
143              miscReg <= MISCREG_CR15));
144    regVal[miscReg] = val;
145}
146
147void
148ISA::setMiscReg(int miscReg, MiscReg val, ThreadContext * tc)
149{
150    MiscReg newVal = val;
151    switch(miscReg)
152    {
153      case MISCREG_CR0:
154        {
155            CR0 toggled = regVal[miscReg] ^ val;
156            CR0 newCR0 = val;
157            Efer efer = regVal[MISCREG_EFER];
158            if (toggled.pg && efer.lme) {
159                if (newCR0.pg) {
160                    //Turning on long mode
161                    efer.lma = 1;
162                    regVal[MISCREG_EFER] = efer;
163                } else {
164                    //Turning off long mode
165                    efer.lma = 0;
166                    regVal[MISCREG_EFER] = efer;
167                }
168            }
169            if (toggled.pg) {
170                tc->getITBPtr()->invalidateAll();
171                tc->getDTBPtr()->invalidateAll();
172            }
173            //This must always be 1.
174            newCR0.et = 1;
175            newVal = newCR0;
176            updateHandyM5Reg(regVal[MISCREG_EFER],
177                             newCR0,
178                             regVal[MISCREG_CS_ATTR],
179                             regVal[MISCREG_SS_ATTR],
180                             regVal[MISCREG_RFLAGS]);
181        }
182        break;
183      case MISCREG_CR2:
184        break;
185      case MISCREG_CR3:
186        tc->getITBPtr()->invalidateNonGlobal();
187        tc->getDTBPtr()->invalidateNonGlobal();
188        break;
189      case MISCREG_CR4:
190        {
191            CR4 toggled = regVal[miscReg] ^ val;
192            if (toggled.pae || toggled.pse || toggled.pge) {
193                tc->getITBPtr()->invalidateAll();
194                tc->getDTBPtr()->invalidateAll();
195            }
196        }
197        break;
198      case MISCREG_CR8:
199        break;
200      case MISCREG_CS_ATTR:
201        {
202            SegAttr toggled = regVal[miscReg] ^ val;
203            SegAttr newCSAttr = val;
204            if (toggled.longMode) {
205                if (newCSAttr.longMode) {
206                    regVal[MISCREG_ES_EFF_BASE] = 0;
207                    regVal[MISCREG_CS_EFF_BASE] = 0;
208                    regVal[MISCREG_SS_EFF_BASE] = 0;
209                    regVal[MISCREG_DS_EFF_BASE] = 0;
210                } else {
211                    regVal[MISCREG_ES_EFF_BASE] = regVal[MISCREG_ES_BASE];
212                    regVal[MISCREG_CS_EFF_BASE] = regVal[MISCREG_CS_BASE];
213                    regVal[MISCREG_SS_EFF_BASE] = regVal[MISCREG_SS_BASE];
214                    regVal[MISCREG_DS_EFF_BASE] = regVal[MISCREG_DS_BASE];
215                }
216            }
217            updateHandyM5Reg(regVal[MISCREG_EFER],
218                             regVal[MISCREG_CR0],
219                             newCSAttr,
220                             regVal[MISCREG_SS_ATTR],
221                             regVal[MISCREG_RFLAGS]);
222        }
223        break;
224      case MISCREG_SS_ATTR:
225        updateHandyM5Reg(regVal[MISCREG_EFER],
226                         regVal[MISCREG_CR0],
227                         regVal[MISCREG_CS_ATTR],
228                         val,
229                         regVal[MISCREG_RFLAGS]);
230        break;
231      // These segments always actually use their bases, or in other words
232      // their effective bases must stay equal to their actual bases.
233      case MISCREG_FS_BASE:
234      case MISCREG_GS_BASE:
235      case MISCREG_HS_BASE:
236      case MISCREG_TSL_BASE:
237      case MISCREG_TSG_BASE:
238      case MISCREG_TR_BASE:
239      case MISCREG_IDTR_BASE:
240        regVal[MISCREG_SEG_EFF_BASE(miscReg - MISCREG_SEG_BASE_BASE)] = val;
241        break;
242      // These segments ignore their bases in 64 bit mode.
243      // their effective bases must stay equal to their actual bases.
244      case MISCREG_ES_BASE:
245      case MISCREG_CS_BASE:
246      case MISCREG_SS_BASE:
247      case MISCREG_DS_BASE:
248        {
249            Efer efer = regVal[MISCREG_EFER];
250            SegAttr csAttr = regVal[MISCREG_CS_ATTR];
251            if (!efer.lma || !csAttr.longMode) // Check for non 64 bit mode.
252                regVal[MISCREG_SEG_EFF_BASE(miscReg -
253                        MISCREG_SEG_BASE_BASE)] = val;
254        }
255        break;
256      case MISCREG_TSC:
257        regVal[MISCREG_TSC] = val - tc->getCpuPtr()->curCycle();
258        return;
259      case MISCREG_DR0:
260      case MISCREG_DR1:
261      case MISCREG_DR2:
262      case MISCREG_DR3:
263        /* These should eventually set up breakpoints. */
264        break;
265      case MISCREG_DR4:
266        miscReg = MISCREG_DR6;
267        /* Fall through to have the same effects as DR6. */
268      case MISCREG_DR6:
269        {
270            DR6 dr6 = regVal[MISCREG_DR6];
271            DR6 newDR6 = val;
272            dr6.b0 = newDR6.b0;
273            dr6.b1 = newDR6.b1;
274            dr6.b2 = newDR6.b2;
275            dr6.b3 = newDR6.b3;
276            dr6.bd = newDR6.bd;
277            dr6.bs = newDR6.bs;
278            dr6.bt = newDR6.bt;
279            newVal = dr6;
280        }
281        break;
282      case MISCREG_DR5:
283        miscReg = MISCREG_DR7;
284        /* Fall through to have the same effects as DR7. */
285      case MISCREG_DR7:
286        {
287            DR7 dr7 = regVal[MISCREG_DR7];
288            DR7 newDR7 = val;
289            dr7.l0 = newDR7.l0;
290            dr7.g0 = newDR7.g0;
291            if (dr7.l0 || dr7.g0) {
292                panic("Debug register breakpoints not implemented.\n");
293            } else {
294                /* Disable breakpoint 0. */
295            }
296            dr7.l1 = newDR7.l1;
297            dr7.g1 = newDR7.g1;
298            if (dr7.l1 || dr7.g1) {
299                panic("Debug register breakpoints not implemented.\n");
300            } else {
301                /* Disable breakpoint 1. */
302            }
303            dr7.l2 = newDR7.l2;
304            dr7.g2 = newDR7.g2;
305            if (dr7.l2 || dr7.g2) {
306                panic("Debug register breakpoints not implemented.\n");
307            } else {
308                /* Disable breakpoint 2. */
309            }
310            dr7.l3 = newDR7.l3;
311            dr7.g3 = newDR7.g3;
312            if (dr7.l3 || dr7.g3) {
313                panic("Debug register breakpoints not implemented.\n");
314            } else {
315                /* Disable breakpoint 3. */
316            }
317            dr7.gd = newDR7.gd;
318            dr7.rw0 = newDR7.rw0;
319            dr7.len0 = newDR7.len0;
320            dr7.rw1 = newDR7.rw1;
321            dr7.len1 = newDR7.len1;
322            dr7.rw2 = newDR7.rw2;
323            dr7.len2 = newDR7.len2;
324            dr7.rw3 = newDR7.rw3;
325            dr7.len3 = newDR7.len3;
326        }
327        break;
328      case MISCREG_M5_REG:
329        // Writing anything to the m5reg with side effects makes it update
330        // based on the current values of the relevant registers. The actual
331        // value written is discarded.
332        updateHandyM5Reg(regVal[MISCREG_EFER],
333                         regVal[MISCREG_CR0],
334                         regVal[MISCREG_CS_ATTR],
335                         regVal[MISCREG_SS_ATTR],
336                         regVal[MISCREG_RFLAGS]);
337        return;
338      default:
339        break;
340    }
341    setMiscRegNoEffect(miscReg, newVal);
342}
343
344void
345ISA::serialize(EventManager *em, std::ostream & os)
346{
347    SERIALIZE_ARRAY(regVal, NumMiscRegs);
348}
349
350void
351ISA::unserialize(EventManager *em, Checkpoint * cp,
352                 const std::string & section)
353{
354    UNSERIALIZE_ARRAY(regVal, NumMiscRegs);
355    updateHandyM5Reg(regVal[MISCREG_EFER],
356                     regVal[MISCREG_CR0],
357                     regVal[MISCREG_CS_ATTR],
358                     regVal[MISCREG_SS_ATTR],
359                     regVal[MISCREG_RFLAGS]);
360}
361
362}
363