cpu_impl.hh revision 3349
1/*
2 * Copyright (c) 2006 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: Kevin Lim
29 */
30
31#include <list>
32#include <string>
33
34#include "base/refcnt.hh"
35#include "cpu/base_dyn_inst.hh"
36#include "cpu/checker/cpu.hh"
37#include "cpu/simple_thread.hh"
38#include "cpu/thread_context.hh"
39#include "cpu/static_inst.hh"
40#include "sim/sim_object.hh"
41#include "sim/stats.hh"
42
43#if FULL_SYSTEM
44#include "arch/vtophys.hh"
45#endif // FULL_SYSTEM
46
47using namespace std;
48//The CheckerCPU does alpha only
49using namespace AlphaISA;
50
51template <class DynInstPtr>
52void
53Checker<DynInstPtr>::verify(DynInstPtr &completed_inst)
54{
55    DynInstPtr inst;
56
57    // Either check this instruction, or add it to a list of
58    // instructions waiting to be checked.  Instructions must be
59    // checked in program order, so if a store has committed yet not
60    // completed, there may be some instructions that are waiting
61    // behind it that have completed and must be checked.
62    if (!instList.empty()) {
63        if (youngestSN < completed_inst->seqNum) {
64            DPRINTF(Checker, "Adding instruction [sn:%lli] PC:%#x to list.\n",
65                    completed_inst->seqNum, completed_inst->readPC());
66            instList.push_back(completed_inst);
67            youngestSN = completed_inst->seqNum;
68        }
69
70        if (!instList.front()->isCompleted()) {
71            return;
72        } else {
73            inst = instList.front();
74            instList.pop_front();
75        }
76    } else {
77        if (!completed_inst->isCompleted()) {
78            if (youngestSN < completed_inst->seqNum) {
79                DPRINTF(Checker, "Adding instruction [sn:%lli] PC:%#x to list.\n",
80                        completed_inst->seqNum, completed_inst->readPC());
81                instList.push_back(completed_inst);
82                youngestSN = completed_inst->seqNum;
83            }
84            return;
85        } else {
86            if (youngestSN < completed_inst->seqNum) {
87                inst = completed_inst;
88                youngestSN = completed_inst->seqNum;
89            } else {
90                return;
91            }
92        }
93    }
94
95    unverifiedInst = inst;
96
97    // Try to check all instructions that are completed, ending if we
98    // run out of instructions to check or if an instruction is not
99    // yet completed.
100    while (1) {
101        DPRINTF(Checker, "Processing instruction [sn:%lli] PC:%#x.\n",
102                inst->seqNum, inst->readPC());
103        unverifiedResult.integer = inst->readIntResult();
104        unverifiedReq = inst->req;
105        unverifiedMemData = inst->memData;
106        numCycles++;
107
108        Fault fault = NoFault;
109
110        // maintain $r0 semantics
111        thread->setIntReg(ZeroReg, 0);
112#ifdef TARGET_ALPHA
113        thread->setFloatRegDouble(ZeroReg, 0.0);
114#endif // TARGET_ALPHA
115
116        // Check if any recent PC changes match up with anything we
117        // expect to happen.  This is mostly to check if traps or
118        // PC-based events have occurred in both the checker and CPU.
119        if (changedPC) {
120            DPRINTF(Checker, "Changed PC recently to %#x\n",
121                    thread->readPC());
122            if (willChangePC) {
123                if (newPC == thread->readPC()) {
124                    DPRINTF(Checker, "Changed PC matches expected PC\n");
125                } else {
126                    warn("%lli: Changed PC does not match expected PC, "
127                         "changed: %#x, expected: %#x",
128                         curTick, thread->readPC(), newPC);
129                    CheckerCPU::handleError();
130                }
131                willChangePC = false;
132            }
133            changedPC = false;
134        }
135        if (changedNextPC) {
136            DPRINTF(Checker, "Changed NextPC recently to %#x\n",
137                    thread->readNextPC());
138            changedNextPC = false;
139        }
140
141        // Try to fetch the instruction
142
143#if FULL_SYSTEM
144#define IFETCH_FLAGS(pc)	((pc) & 1) ? PHYSICAL : 0
145#else
146#define IFETCH_FLAGS(pc)	0
147#endif
148
149        uint64_t fetch_PC = thread->readPC() & ~3;
150
151        // set up memory request for instruction fetch
152        memReq = new Request(inst->threadNumber, fetch_PC,
153                             sizeof(uint32_t),
154                             IFETCH_FLAGS(thread->readPC()),
155                             fetch_PC, thread->readCpuId(), inst->threadNumber);
156
157        bool succeeded = translateInstReq(memReq);
158
159        if (!succeeded) {
160            if (inst->getFault() == NoFault) {
161                // In this case the instruction was not a dummy
162                // instruction carrying an ITB fault.  In the single
163                // threaded case the ITB should still be able to
164                // translate this instruction; in the SMT case it's
165                // possible that its ITB entry was kicked out.
166                warn("%lli: Instruction PC %#x was not found in the ITB!",
167                     curTick, thread->readPC());
168                handleError(inst);
169
170                // go to the next instruction
171                thread->setPC(thread->readNextPC());
172                thread->setNextPC(thread->readNextPC() + sizeof(MachInst));
173
174                break;
175            } else {
176                // The instruction is carrying an ITB fault.  Handle
177                // the fault and see if our results match the CPU on
178                // the next tick().
179                fault = inst->getFault();
180            }
181        }
182
183        if (fault == NoFault) {
184            PacketPtr pkt = new Packet(memReq, Packet::ReadReq,
185                                     Packet::Broadcast);
186
187            pkt->dataStatic(&machInst);
188
189            icachePort->sendFunctional(pkt);
190
191            delete pkt;
192
193            // keep an instruction count
194            numInst++;
195
196            // decode the instruction
197            machInst = gtoh(machInst);
198            // Checks that the instruction matches what we expected it to be.
199            // Checks both the machine instruction and the PC.
200            validateInst(inst);
201
202            curStaticInst = StaticInst::decode(makeExtMI(machInst,
203                                                         thread->readPC()));
204
205#if FULL_SYSTEM
206            thread->setInst(machInst);
207#endif // FULL_SYSTEM
208
209            fault = inst->getFault();
210        }
211
212        // Discard fetch's memReq.
213        delete memReq;
214        memReq = NULL;
215
216        // Either the instruction was a fault and we should process the fault,
217        // or we should just go ahead execute the instruction.  This assumes
218        // that the instruction is properly marked as a fault.
219        if (fault == NoFault) {
220
221            thread->funcExeInst++;
222
223            if (!inst->isUnverifiable())
224                fault = curStaticInst->execute(this, NULL);
225
226            // Checks to make sure instrution results are correct.
227            validateExecution(inst);
228
229            if (curStaticInst->isLoad()) {
230                ++numLoad;
231            }
232        }
233
234        if (fault != NoFault) {
235#if FULL_SYSTEM
236            fault->invoke(tc);
237            willChangePC = true;
238            newPC = thread->readPC();
239            DPRINTF(Checker, "Fault, PC is now %#x\n", newPC);
240#endif
241        } else {
242#if THE_ISA != MIPS_ISA
243            // go to the next instruction
244            thread->setPC(thread->readNextPC());
245            thread->setNextPC(thread->readNextPC() + sizeof(MachInst));
246#else
247            // go to the next instruction
248            thread->setPC(thread->readNextPC());
249            thread->setNextPC(thread->readNextNPC());
250            thread->setNextNPC(thread->readNextNPC() + sizeof(MachInst));
251#endif
252
253        }
254
255#if FULL_SYSTEM
256        // @todo: Determine if these should happen only if the
257        // instruction hasn't faulted.  In the SimpleCPU case this may
258        // not be true, but in the O3 or Ozone case this may be true.
259        Addr oldpc;
260        int count = 0;
261        do {
262            oldpc = thread->readPC();
263            system->pcEventQueue.service(tc);
264            count++;
265        } while (oldpc != thread->readPC());
266        if (count > 1) {
267            willChangePC = true;
268            newPC = thread->readPC();
269            DPRINTF(Checker, "PC Event, PC is now %#x\n", newPC);
270        }
271#endif
272
273        // @todo:  Optionally can check all registers. (Or just those
274        // that have been modified).
275        validateState();
276
277        if (memReq) {
278            delete memReq;
279            memReq = NULL;
280        }
281
282        // Continue verifying instructions if there's another completed
283        // instruction waiting to be verified.
284        if (instList.empty()) {
285            break;
286        } else if (instList.front()->isCompleted()) {
287            inst = instList.front();
288            instList.pop_front();
289        } else {
290            break;
291        }
292    }
293    unverifiedInst = NULL;
294}
295
296template <class DynInstPtr>
297void
298Checker<DynInstPtr>::switchOut()
299{
300    instList.clear();
301}
302
303template <class DynInstPtr>
304void
305Checker<DynInstPtr>::takeOverFrom(BaseCPU *oldCPU)
306{
307}
308
309template <class DynInstPtr>
310void
311Checker<DynInstPtr>::validateInst(DynInstPtr &inst)
312{
313    if (inst->readPC() != thread->readPC()) {
314        warn("%lli: PCs do not match! Inst: %#x, checker: %#x",
315             curTick, inst->readPC(), thread->readPC());
316        if (changedPC) {
317            warn("%lli: Changed PCs recently, may not be an error",
318                 curTick);
319        } else {
320            handleError(inst);
321        }
322    }
323
324    MachInst mi = static_cast<MachInst>(inst->staticInst->machInst);
325
326    if (mi != machInst) {
327        warn("%lli: Binary instructions do not match! Inst: %#x, "
328             "checker: %#x",
329             curTick, mi, machInst);
330        handleError(inst);
331    }
332}
333
334template <class DynInstPtr>
335void
336Checker<DynInstPtr>::validateExecution(DynInstPtr &inst)
337{
338    bool result_mismatch = false;
339    if (inst->numDestRegs()) {
340        // @todo: Support more destination registers.
341        if (inst->isUnverifiable()) {
342            // Unverifiable instructions assume they were executed
343            // properly by the CPU. Grab the result from the
344            // instruction and write it to the register.
345            copyResult(inst);
346        } else if (result.integer != inst->readIntResult()) {
347            result_mismatch = true;
348        }
349    }
350
351    if (result_mismatch) {
352        warn("%lli: Instruction results do not match! (Values may not "
353             "actually be integers) Inst: %#x, checker: %#x",
354             curTick, inst->readIntResult(), result.integer);
355
356        // It's useful to verify load values from memory, but in MP
357        // systems the value obtained at execute may be different than
358        // the value obtained at completion.  Similarly DMA can
359        // present the same problem on even UP systems.  Thus there is
360        // the option to only warn on loads having a result error.
361        if (inst->isLoad() && warnOnlyOnLoadError) {
362            copyResult(inst);
363        } else {
364            handleError(inst);
365        }
366    }
367
368    if (inst->readNextPC() != thread->readNextPC()) {
369        warn("%lli: Instruction next PCs do not match! Inst: %#x, "
370             "checker: %#x",
371             curTick, inst->readNextPC(), thread->readNextPC());
372        handleError(inst);
373    }
374
375    // Checking side effect registers can be difficult if they are not
376    // checked simultaneously with the execution of the instruction.
377    // This is because other valid instructions may have modified
378    // these registers in the meantime, and their values are not
379    // stored within the DynInst.
380    while (!miscRegIdxs.empty()) {
381        int misc_reg_idx = miscRegIdxs.front();
382        miscRegIdxs.pop();
383
384        if (inst->tcBase()->readMiscReg(misc_reg_idx) !=
385            thread->readMiscReg(misc_reg_idx)) {
386            warn("%lli: Misc reg idx %i (side effect) does not match! "
387                 "Inst: %#x, checker: %#x",
388                 curTick, misc_reg_idx,
389                 inst->tcBase()->readMiscReg(misc_reg_idx),
390                 thread->readMiscReg(misc_reg_idx));
391            handleError(inst);
392        }
393    }
394}
395
396template <class DynInstPtr>
397void
398Checker<DynInstPtr>::validateState()
399{
400    if (updateThisCycle) {
401        warn("%lli: Instruction PC %#x results didn't match up, copying all "
402             "registers from main CPU", curTick, unverifiedInst->readPC());
403        // Heavy-weight copying of all registers
404        thread->copyArchRegs(unverifiedInst->tcBase());
405        // Also advance the PC.  Hopefully no PC-based events happened.
406#if THE_ISA != MIPS_ISA
407        // go to the next instruction
408        thread->setPC(thread->readNextPC());
409        thread->setNextPC(thread->readNextPC() + sizeof(MachInst));
410#else
411        // go to the next instruction
412        thread->setPC(thread->readNextPC());
413        thread->setNextPC(thread->readNextNPC());
414        thread->setNextNPC(thread->readNextNPC() + sizeof(MachInst));
415#endif
416        updateThisCycle = false;
417    }
418}
419
420template <class DynInstPtr>
421void
422Checker<DynInstPtr>::copyResult(DynInstPtr &inst)
423{
424    RegIndex idx = inst->destRegIdx(0);
425    if (idx < TheISA::FP_Base_DepTag) {
426        thread->setIntReg(idx, inst->readIntResult());
427    } else if (idx < TheISA::Fpcr_DepTag) {
428        thread->setFloatRegBits(idx, inst->readIntResult());
429    } else {
430        thread->setMiscReg(idx, inst->readIntResult());
431    }
432}
433
434template <class DynInstPtr>
435void
436Checker<DynInstPtr>::dumpAndExit(DynInstPtr &inst)
437{
438    cprintf("Error detected, instruction information:\n");
439    cprintf("PC:%#x, nextPC:%#x\n[sn:%lli]\n[tid:%i]\n"
440            "Completed:%i\n",
441            inst->readPC(),
442            inst->readNextPC(),
443            inst->seqNum,
444            inst->threadNumber,
445            inst->isCompleted());
446    inst->dump();
447    CheckerCPU::dumpAndExit();
448}
449
450template <class DynInstPtr>
451void
452Checker<DynInstPtr>::dumpInsts()
453{
454    int num = 0;
455
456    InstListIt inst_list_it = --(instList.end());
457
458    cprintf("Inst list size: %i\n", instList.size());
459
460    while (inst_list_it != instList.end())
461    {
462        cprintf("Instruction:%i\n",
463                num);
464
465        cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n"
466                "Completed:%i\n",
467                (*inst_list_it)->readPC(),
468                (*inst_list_it)->seqNum,
469                (*inst_list_it)->threadNumber,
470                (*inst_list_it)->isCompleted());
471
472        cprintf("\n");
473
474        inst_list_it--;
475        ++num;
476    }
477
478}
479