tlb.cc revision 12140
1/*
2 * Copyright (c) 2007-2008 The Hewlett-Packard Development Company
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Gabe Black
38 */
39
40#include "arch/x86/tlb.hh"
41
42#include <cstring>
43#include <memory>
44
45#include "arch/generic/mmapped_ipr.hh"
46#include "arch/x86/faults.hh"
47#include "arch/x86/insts/microldstop.hh"
48#include "arch/x86/pagetable_walker.hh"
49#include "arch/x86/regs/misc.hh"
50#include "arch/x86/regs/msr.hh"
51#include "arch/x86/x86_traits.hh"
52#include "base/trace.hh"
53#include "cpu/thread_context.hh"
54#include "debug/TLB.hh"
55#include "mem/page_table.hh"
56#include "mem/request.hh"
57#include "sim/full_system.hh"
58#include "sim/process.hh"
59
60namespace X86ISA {
61
62TLB::TLB(const Params *p)
63    : BaseTLB(p), configAddress(0), size(p->size),
64      tlb(size), lruSeq(0)
65{
66    if (!size)
67        fatal("TLBs must have a non-zero size.\n");
68
69    for (int x = 0; x < size; x++) {
70        tlb[x].trieHandle = NULL;
71        freeList.push_back(&tlb[x]);
72    }
73
74    walker = p->walker;
75    walker->setTLB(this);
76}
77
78void
79TLB::evictLRU()
80{
81    // Find the entry with the lowest (and hence least recently updated)
82    // sequence number.
83
84    unsigned lru = 0;
85    for (unsigned i = 1; i < size; i++) {
86        if (tlb[i].lruSeq < tlb[lru].lruSeq)
87            lru = i;
88    }
89
90    assert(tlb[lru].trieHandle);
91    trie.remove(tlb[lru].trieHandle);
92    tlb[lru].trieHandle = NULL;
93    freeList.push_back(&tlb[lru]);
94}
95
96TlbEntry *
97TLB::insert(Addr vpn, TlbEntry &entry)
98{
99    // If somebody beat us to it, just use that existing entry.
100    TlbEntry *newEntry = trie.lookup(vpn);
101    if (newEntry) {
102        assert(newEntry->vaddr == vpn);
103        return newEntry;
104    }
105
106    if (freeList.empty())
107        evictLRU();
108
109    newEntry = freeList.front();
110    freeList.pop_front();
111
112    *newEntry = entry;
113    newEntry->lruSeq = nextSeq();
114    newEntry->vaddr = vpn;
115    newEntry->trieHandle =
116    trie.insert(vpn, TlbEntryTrie::MaxBits - entry.logBytes, newEntry);
117    return newEntry;
118}
119
120TlbEntry *
121TLB::lookup(Addr va, bool update_lru)
122{
123    TlbEntry *entry = trie.lookup(va);
124    if (entry && update_lru)
125        entry->lruSeq = nextSeq();
126    return entry;
127}
128
129void
130TLB::flushAll()
131{
132    DPRINTF(TLB, "Invalidating all entries.\n");
133    for (unsigned i = 0; i < size; i++) {
134        if (tlb[i].trieHandle) {
135            trie.remove(tlb[i].trieHandle);
136            tlb[i].trieHandle = NULL;
137            freeList.push_back(&tlb[i]);
138        }
139    }
140}
141
142void
143TLB::setConfigAddress(uint32_t addr)
144{
145    configAddress = addr;
146}
147
148void
149TLB::flushNonGlobal()
150{
151    DPRINTF(TLB, "Invalidating all non global entries.\n");
152    for (unsigned i = 0; i < size; i++) {
153        if (tlb[i].trieHandle && !tlb[i].global) {
154            trie.remove(tlb[i].trieHandle);
155            tlb[i].trieHandle = NULL;
156            freeList.push_back(&tlb[i]);
157        }
158    }
159}
160
161void
162TLB::demapPage(Addr va, uint64_t asn)
163{
164    TlbEntry *entry = trie.lookup(va);
165    if (entry) {
166        trie.remove(entry->trieHandle);
167        entry->trieHandle = NULL;
168        freeList.push_back(entry);
169    }
170}
171
172Fault
173TLB::translateInt(RequestPtr req, ThreadContext *tc)
174{
175    DPRINTF(TLB, "Addresses references internal memory.\n");
176    Addr vaddr = req->getVaddr();
177    Addr prefix = (vaddr >> 3) & IntAddrPrefixMask;
178    if (prefix == IntAddrPrefixCPUID) {
179        panic("CPUID memory space not yet implemented!\n");
180    } else if (prefix == IntAddrPrefixMSR) {
181        vaddr = (vaddr >> 3) & ~IntAddrPrefixMask;
182        req->setFlags(Request::MMAPPED_IPR);
183
184        MiscRegIndex regNum;
185        if (!msrAddrToIndex(regNum, vaddr))
186            return std::make_shared<GeneralProtection>(0);
187
188        //The index is multiplied by the size of a MiscReg so that
189        //any memory dependence calculations will not see these as
190        //overlapping.
191        req->setPaddr((Addr)regNum * sizeof(MiscReg));
192        return NoFault;
193    } else if (prefix == IntAddrPrefixIO) {
194        // TODO If CPL > IOPL or in virtual mode, check the I/O permission
195        // bitmap in the TSS.
196
197        Addr IOPort = vaddr & ~IntAddrPrefixMask;
198        // Make sure the address fits in the expected 16 bit IO address
199        // space.
200        assert(!(IOPort & ~0xFFFF));
201        if (IOPort == 0xCF8 && req->getSize() == 4) {
202            req->setFlags(Request::MMAPPED_IPR);
203            req->setPaddr(MISCREG_PCI_CONFIG_ADDRESS * sizeof(MiscReg));
204        } else if ((IOPort & ~mask(2)) == 0xCFC) {
205            req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
206            Addr configAddress =
207                tc->readMiscRegNoEffect(MISCREG_PCI_CONFIG_ADDRESS);
208            if (bits(configAddress, 31, 31)) {
209                req->setPaddr(PhysAddrPrefixPciConfig |
210                        mbits(configAddress, 30, 2) |
211                        (IOPort & mask(2)));
212            } else {
213                req->setPaddr(PhysAddrPrefixIO | IOPort);
214            }
215        } else {
216            req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
217            req->setPaddr(PhysAddrPrefixIO | IOPort);
218        }
219        return NoFault;
220    } else {
221        panic("Access to unrecognized internal address space %#x.\n",
222                prefix);
223    }
224}
225
226Fault
227TLB::finalizePhysical(RequestPtr req, ThreadContext *tc, Mode mode) const
228{
229    Addr paddr = req->getPaddr();
230
231    AddrRange m5opRange(0xFFFF0000, 0xFFFFFFFF);
232
233    if (m5opRange.contains(paddr)) {
234        req->setFlags(Request::MMAPPED_IPR | Request::GENERIC_IPR |
235                      Request::STRICT_ORDER);
236        req->setPaddr(GenericISA::iprAddressPseudoInst((paddr >> 8) & 0xFF,
237                                                       paddr & 0xFF));
238    } else if (FullSystem) {
239        // Check for an access to the local APIC
240        LocalApicBase localApicBase =
241            tc->readMiscRegNoEffect(MISCREG_APIC_BASE);
242        AddrRange apicRange(localApicBase.base * PageBytes,
243                            (localApicBase.base + 1) * PageBytes - 1);
244
245        if (apicRange.contains(paddr)) {
246            // The Intel developer's manuals say the below restrictions apply,
247            // but the linux kernel, because of a compiler optimization, breaks
248            // them.
249            /*
250            // Check alignment
251            if (paddr & ((32/8) - 1))
252                return new GeneralProtection(0);
253            // Check access size
254            if (req->getSize() != (32/8))
255                return new GeneralProtection(0);
256            */
257            // Force the access to be uncacheable.
258            req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
259            req->setPaddr(x86LocalAPICAddress(tc->contextId(),
260                                              paddr - apicRange.start()));
261        }
262    }
263
264    return NoFault;
265}
266
267Fault
268TLB::translate(RequestPtr req, ThreadContext *tc, Translation *translation,
269        Mode mode, bool &delayedResponse, bool timing)
270{
271    Request::Flags flags = req->getFlags();
272    int seg = flags & SegmentFlagMask;
273    bool storeCheck = flags & (StoreCheck << FlagShift);
274
275    delayedResponse = false;
276
277    // If this is true, we're dealing with a request to a non-memory address
278    // space.
279    if (seg == SEGMENT_REG_MS) {
280        return translateInt(req, tc);
281    }
282
283    Addr vaddr = req->getVaddr();
284    DPRINTF(TLB, "Translating vaddr %#x.\n", vaddr);
285
286    HandyM5Reg m5Reg = tc->readMiscRegNoEffect(MISCREG_M5_REG);
287
288    // If protected mode has been enabled...
289    if (m5Reg.prot) {
290        DPRINTF(TLB, "In protected mode.\n");
291        // If we're not in 64-bit mode, do protection/limit checks
292        if (m5Reg.mode != LongMode) {
293            DPRINTF(TLB, "Not in long mode. Checking segment protection.\n");
294            // Check for a NULL segment selector.
295            if (!(seg == SEGMENT_REG_TSG || seg == SYS_SEGMENT_REG_IDTR ||
296                        seg == SEGMENT_REG_HS || seg == SEGMENT_REG_LS)
297                    && !tc->readMiscRegNoEffect(MISCREG_SEG_SEL(seg)))
298                return std::make_shared<GeneralProtection>(0);
299            bool expandDown = false;
300            SegAttr attr = tc->readMiscRegNoEffect(MISCREG_SEG_ATTR(seg));
301            if (seg >= SEGMENT_REG_ES && seg <= SEGMENT_REG_HS) {
302                if (!attr.writable && (mode == Write || storeCheck))
303                    return std::make_shared<GeneralProtection>(0);
304                if (!attr.readable && mode == Read)
305                    return std::make_shared<GeneralProtection>(0);
306                expandDown = attr.expandDown;
307
308            }
309            Addr base = tc->readMiscRegNoEffect(MISCREG_SEG_BASE(seg));
310            Addr limit = tc->readMiscRegNoEffect(MISCREG_SEG_LIMIT(seg));
311            bool sizeOverride = (flags & (AddrSizeFlagBit << FlagShift));
312            unsigned logSize = sizeOverride ? (unsigned)m5Reg.altAddr
313                                            : (unsigned)m5Reg.defAddr;
314            int size = (1 << logSize) * 8;
315            Addr offset = bits(vaddr - base, size - 1, 0);
316            Addr endOffset = offset + req->getSize() - 1;
317            if (expandDown) {
318                DPRINTF(TLB, "Checking an expand down segment.\n");
319                warn_once("Expand down segments are untested.\n");
320                if (offset <= limit || endOffset <= limit)
321                    return std::make_shared<GeneralProtection>(0);
322            } else {
323                if (offset > limit || endOffset > limit)
324                    return std::make_shared<GeneralProtection>(0);
325            }
326        }
327        if (m5Reg.submode != SixtyFourBitMode ||
328                (flags & (AddrSizeFlagBit << FlagShift)))
329            vaddr &= mask(32);
330        // If paging is enabled, do the translation.
331        if (m5Reg.paging) {
332            DPRINTF(TLB, "Paging enabled.\n");
333            // The vaddr already has the segment base applied.
334            TlbEntry *entry = lookup(vaddr);
335            if (mode == Read) {
336                rdAccesses++;
337            } else {
338                wrAccesses++;
339            }
340            if (!entry) {
341                DPRINTF(TLB, "Handling a TLB miss for "
342                        "address %#x at pc %#x.\n",
343                        vaddr, tc->instAddr());
344                if (mode == Read) {
345                    rdMisses++;
346                } else {
347                    wrMisses++;
348                }
349                if (FullSystem) {
350                    Fault fault = walker->start(tc, translation, req, mode);
351                    if (timing || fault != NoFault) {
352                        // This gets ignored in atomic mode.
353                        delayedResponse = true;
354                        return fault;
355                    }
356                    entry = lookup(vaddr);
357                    assert(entry);
358                } else {
359                    Process *p = tc->getProcessPtr();
360                    TlbEntry newEntry;
361                    bool success = p->pTable->lookup(vaddr, newEntry);
362                    if (!success && mode != Execute) {
363                        // Check if we just need to grow the stack.
364                        if (p->fixupStackFault(vaddr)) {
365                            // If we did, lookup the entry for the new page.
366                            success = p->pTable->lookup(vaddr, newEntry);
367                        }
368                    }
369                    if (!success) {
370                        return std::make_shared<PageFault>(vaddr, true, mode,
371                                                           true, false);
372                    } else {
373                        Addr alignedVaddr = p->pTable->pageAlign(vaddr);
374                        DPRINTF(TLB, "Mapping %#x to %#x\n", alignedVaddr,
375                                newEntry.pageStart());
376                        entry = insert(alignedVaddr, newEntry);
377                    }
378                    DPRINTF(TLB, "Miss was serviced.\n");
379                }
380            }
381
382            DPRINTF(TLB, "Entry found with paddr %#x, "
383                    "doing protection checks.\n", entry->paddr);
384            // Do paging protection checks.
385            bool inUser = (m5Reg.cpl == 3 &&
386                    !(flags & (CPL0FlagBit << FlagShift)));
387            CR0 cr0 = tc->readMiscRegNoEffect(MISCREG_CR0);
388            bool badWrite = (!entry->writable && (inUser || cr0.wp));
389            if ((inUser && !entry->user) || (mode == Write && badWrite)) {
390                // The page must have been present to get into the TLB in
391                // the first place. We'll assume the reserved bits are
392                // fine even though we're not checking them.
393                return std::make_shared<PageFault>(vaddr, true, mode, inUser,
394                                                   false);
395            }
396            if (storeCheck && badWrite) {
397                // This would fault if this were a write, so return a page
398                // fault that reflects that happening.
399                return std::make_shared<PageFault>(vaddr, true, Write, inUser,
400                                                   false);
401            }
402
403            Addr paddr = entry->paddr | (vaddr & mask(entry->logBytes));
404            DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, paddr);
405            req->setPaddr(paddr);
406            if (entry->uncacheable)
407                req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
408        } else {
409            //Use the address which already has segmentation applied.
410            DPRINTF(TLB, "Paging disabled.\n");
411            DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, vaddr);
412            req->setPaddr(vaddr);
413        }
414    } else {
415        // Real mode
416        DPRINTF(TLB, "In real mode.\n");
417        DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, vaddr);
418        req->setPaddr(vaddr);
419    }
420
421    return finalizePhysical(req, tc, mode);
422}
423
424Fault
425TLB::translateAtomic(RequestPtr req, ThreadContext *tc, Mode mode)
426{
427    bool delayedResponse;
428    return TLB::translate(req, tc, NULL, mode, delayedResponse, false);
429}
430
431void
432TLB::translateTiming(RequestPtr req, ThreadContext *tc,
433        Translation *translation, Mode mode)
434{
435    bool delayedResponse;
436    assert(translation);
437    Fault fault =
438        TLB::translate(req, tc, translation, mode, delayedResponse, true);
439    if (!delayedResponse)
440        translation->finish(fault, req, tc, mode);
441}
442
443Fault
444TLB::translateFunctional(RequestPtr req, ThreadContext *tc, Mode mode)
445{
446    panic("Not implemented\n");
447    return NoFault;
448}
449
450Walker *
451TLB::getWalker()
452{
453    return walker;
454}
455
456void
457TLB::regStats()
458{
459    using namespace Stats;
460
461    rdAccesses
462        .name(name() + ".rdAccesses")
463        .desc("TLB accesses on read requests");
464
465    wrAccesses
466        .name(name() + ".wrAccesses")
467        .desc("TLB accesses on write requests");
468
469    rdMisses
470        .name(name() + ".rdMisses")
471        .desc("TLB misses on read requests");
472
473    wrMisses
474        .name(name() + ".wrMisses")
475        .desc("TLB misses on write requests");
476
477}
478
479void
480TLB::serialize(CheckpointOut &cp) const
481{
482    // Only store the entries in use.
483    uint32_t _size = size - freeList.size();
484    SERIALIZE_SCALAR(_size);
485    SERIALIZE_SCALAR(lruSeq);
486
487    uint32_t _count = 0;
488    for (uint32_t x = 0; x < size; x++) {
489        if (tlb[x].trieHandle != NULL)
490            tlb[x].serializeSection(cp, csprintf("Entry%d", _count++));
491    }
492}
493
494void
495TLB::unserialize(CheckpointIn &cp)
496{
497    // Do not allow to restore with a smaller tlb.
498    uint32_t _size;
499    UNSERIALIZE_SCALAR(_size);
500    if (_size > size) {
501        fatal("TLB size less than the one in checkpoint!");
502    }
503
504    UNSERIALIZE_SCALAR(lruSeq);
505
506    for (uint32_t x = 0; x < _size; x++) {
507        TlbEntry *newEntry = freeList.front();
508        freeList.pop_front();
509
510        newEntry->unserializeSection(cp, csprintf("Entry%d", x));
511        newEntry->trieHandle = trie.insert(newEntry->vaddr,
512            TlbEntryTrie::MaxBits - newEntry->logBytes, newEntry);
513    }
514}
515
516BaseMasterPort *
517TLB::getMasterPort()
518{
519    return &walker->getMasterPort("port");
520}
521
522} // namespace X86ISA
523
524X86ISA::TLB *
525X86TLBParams::create()
526{
527    return new X86ISA::TLB(this);
528}
529