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/*
* Copyright (c) 2007-2008 The Hewlett-Packard Development Company
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "arch/x86/tlb.hh"
#include <cstring>
#include <memory>
#include "arch/x86/faults.hh"
#include "arch/x86/insts/microldstop.hh"
#include "arch/x86/pagetable_walker.hh"
#include "arch/x86/pseudo_inst_abi.hh"
#include "arch/x86/regs/misc.hh"
#include "arch/x86/regs/msr.hh"
#include "arch/x86/x86_traits.hh"
#include "base/trace.hh"
#include "cpu/thread_context.hh"
#include "debug/TLB.hh"
#include "mem/packet_access.hh"
#include "mem/page_table.hh"
#include "mem/request.hh"
#include "sim/full_system.hh"
#include "sim/process.hh"
#include "sim/pseudo_inst.hh"
namespace gem5
{
namespace X86ISA {
TLB::TLB(const Params &p)
: BaseTLB(p), configAddress(0), size(p.size),
tlb(size), lruSeq(0), m5opRange(p.system->m5opRange()), stats(this)
{
if (!size)
fatal("TLBs must have a non-zero size.\n");
for (int x = 0; x < size; x++) {
tlb[x].trieHandle = NULL;
freeList.push_back(&tlb[x]);
}
walker = p.walker;
walker->setTLB(this);
}
void
TLB::evictLRU()
{
// Find the entry with the lowest (and hence least recently updated)
// sequence number.
unsigned lru = 0;
for (unsigned i = 1; i < size; i++) {
if (tlb[i].lruSeq < tlb[lru].lruSeq)
lru = i;
}
assert(tlb[lru].trieHandle);
trie.remove(tlb[lru].trieHandle);
tlb[lru].trieHandle = NULL;
freeList.push_back(&tlb[lru]);
}
TlbEntry *
TLB::insert(Addr vpn, const TlbEntry &entry, uint64_t pcid)
{
//Adding pcid to the page address so
//that multiple processes using the same
//tlb do not conflict when using the same
//virtual addresses
vpn = concAddrPcid(vpn, pcid);
// If somebody beat us to it, just use that existing entry.
TlbEntry *newEntry = trie.lookup(vpn);
if (newEntry) {
assert(newEntry->vaddr == vpn);
return newEntry;
}
if (freeList.empty())
evictLRU();
newEntry = freeList.front();
freeList.pop_front();
*newEntry = entry;
newEntry->lruSeq = nextSeq();
newEntry->vaddr = vpn;
if (FullSystem) {
newEntry->trieHandle =
trie.insert(vpn, TlbEntryTrie::MaxBits-entry.logBytes, newEntry);
}
else {
newEntry->trieHandle =
trie.insert(vpn, TlbEntryTrie::MaxBits, newEntry);
}
return newEntry;
}
TlbEntry *
TLB::lookup(Addr va, bool update_lru)
{
TlbEntry *entry = trie.lookup(va);
if (entry && update_lru)
entry->lruSeq = nextSeq();
return entry;
}
void
TLB::flushAll()
{
DPRINTF(TLB, "Invalidating all entries.\n");
for (unsigned i = 0; i < size; i++) {
if (tlb[i].trieHandle) {
trie.remove(tlb[i].trieHandle);
tlb[i].trieHandle = NULL;
freeList.push_back(&tlb[i]);
}
}
}
void
TLB::setConfigAddress(uint32_t addr)
{
configAddress = addr;
}
void
TLB::flushNonGlobal()
{
DPRINTF(TLB, "Invalidating all non global entries.\n");
for (unsigned i = 0; i < size; i++) {
if (tlb[i].trieHandle && !tlb[i].global) {
trie.remove(tlb[i].trieHandle);
tlb[i].trieHandle = NULL;
freeList.push_back(&tlb[i]);
}
}
}
void
TLB::demapPage(Addr va, uint64_t asn)
{
TlbEntry *entry = trie.lookup(va);
if (entry) {
trie.remove(entry->trieHandle);
entry->trieHandle = NULL;
freeList.push_back(entry);
}
}
namespace
{
Cycles
localMiscRegAccess(bool read, RegIndex regNum,
ThreadContext *tc, PacketPtr pkt)
{
if (read) {
RegVal data = htole(tc->readMiscReg(regNum));
assert(pkt->getSize() <= sizeof(RegVal));
pkt->setData((uint8_t *)&data);
} else {
RegVal data = htole(tc->readMiscRegNoEffect(regNum));
assert(pkt->getSize() <= sizeof(RegVal));
pkt->writeData((uint8_t *)&data);
tc->setMiscReg(regNum, letoh(data));
}
return Cycles(1);
}
} // anonymous namespace
Fault
TLB::translateInt(bool read, RequestPtr req, ThreadContext *tc)
{
DPRINTF(TLB, "Addresses references internal memory.\n");
Addr vaddr = req->getVaddr();
Addr prefix = (vaddr >> 3) & IntAddrPrefixMask;
if (prefix == IntAddrPrefixCPUID) {
panic("CPUID memory space not yet implemented!\n");
} else if (prefix == IntAddrPrefixMSR) {
vaddr = (vaddr >> 3) & ~IntAddrPrefixMask;
RegIndex regNum;
if (!msrAddrToIndex(regNum, vaddr))
return std::make_shared<GeneralProtection>(0);
req->setPaddr(req->getVaddr());
req->setLocalAccessor(
[read,regNum](ThreadContext *tc, PacketPtr pkt)
{
return localMiscRegAccess(read, regNum, tc, pkt);
}
);
return NoFault;
} else if (prefix == IntAddrPrefixIO) {
// TODO If CPL > IOPL or in virtual mode, check the I/O permission
// bitmap in the TSS.
Addr IOPort = vaddr & ~IntAddrPrefixMask;
// Make sure the address fits in the expected 16 bit IO address
// space.
assert(!(IOPort & ~0xFFFF));
if (IOPort == 0xCF8 && req->getSize() == 4) {
req->setPaddr(req->getVaddr());
req->setLocalAccessor(
[read](ThreadContext *tc, PacketPtr pkt)
{
return localMiscRegAccess(
read, misc_reg::PciConfigAddress, tc, pkt);
}
);
} else if ((IOPort & ~mask(2)) == 0xCFC) {
req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
Addr configAddress =
tc->readMiscRegNoEffect(misc_reg::PciConfigAddress);
if (bits(configAddress, 31, 31)) {
req->setPaddr(PhysAddrPrefixPciConfig |
mbits(configAddress, 30, 2) |
(IOPort & mask(2)));
} else {
req->setPaddr(PhysAddrPrefixIO | IOPort);
}
} else {
req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
req->setPaddr(PhysAddrPrefixIO | IOPort);
}
return NoFault;
} else {
panic("Access to unrecognized internal address space %#x.\n",
prefix);
}
}
Fault
TLB::finalizePhysical(const RequestPtr &req,
ThreadContext *tc, BaseMMU::Mode mode) const
{
Addr paddr = req->getPaddr();
if (m5opRange.contains(paddr)) {
req->setFlags(Request::STRICT_ORDER);
uint8_t func;
pseudo_inst::decodeAddrOffset(paddr - m5opRange.start(), func);
req->setLocalAccessor(
[func, mode](ThreadContext *tc, PacketPtr pkt) -> Cycles
{
uint64_t ret;
pseudo_inst::pseudoInst<X86PseudoInstABI, true>(tc, func, ret);
if (mode == BaseMMU::Read)
pkt->setLE(ret);
return Cycles(1);
}
);
} else if (FullSystem) {
// Check for an access to the local APIC
LocalApicBase localApicBase =
tc->readMiscRegNoEffect(misc_reg::ApicBase);
AddrRange apicRange(localApicBase.base * PageBytes,
(localApicBase.base + 1) * PageBytes);
if (apicRange.contains(paddr)) {
// The Intel developer's manuals say the below restrictions apply,
// but the linux kernel, because of a compiler optimization, breaks
// them.
/*
// Check alignment
if (paddr & ((32/8) - 1))
return new GeneralProtection(0);
// Check access size
if (req->getSize() != (32/8))
return new GeneralProtection(0);
*/
// Force the access to be uncacheable.
req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
req->setPaddr(x86LocalAPICAddress(tc->contextId(),
paddr - apicRange.start()));
}
}
return NoFault;
}
Fault
TLB::translate(const RequestPtr &req,
ThreadContext *tc, BaseMMU::Translation *translation,
BaseMMU::Mode mode, bool &delayedResponse, bool timing)
{
Request::Flags flags = req->getFlags();
int seg = flags & SegmentFlagMask;
bool storeCheck = flags & Request::READ_MODIFY_WRITE;
delayedResponse = false;
// If this is true, we're dealing with a request to a non-memory address
// space.
if (seg == segment_idx::Ms) {
return translateInt(mode == BaseMMU::Read, req, tc);
}
Addr vaddr = req->getVaddr();
DPRINTF(TLB, "Translating vaddr %#x.\n", vaddr);
HandyM5Reg m5Reg = tc->readMiscRegNoEffect(misc_reg::M5Reg);
const Addr logAddrSize = (flags >> AddrSizeFlagShift) & AddrSizeFlagMask;
const int addrSize = 8 << logAddrSize;
const Addr addrMask = mask(addrSize);
// If protected mode has been enabled...
if (m5Reg.prot) {
DPRINTF(TLB, "In protected mode.\n");
// If we're not in 64-bit mode, do protection/limit checks
if (m5Reg.mode != LongMode) {
DPRINTF(TLB, "Not in long mode. Checking segment protection.\n");
// CPUs won't know to use CS when building fetch requests, so we
// need to override the value of "seg" here if this is a fetch.
if (mode == BaseMMU::Execute)
seg = segment_idx::Cs;
SegAttr attr = tc->readMiscRegNoEffect(misc_reg::segAttr(seg));
// Check for an unusable segment.
if (attr.unusable) {
DPRINTF(TLB, "Unusable segment.\n");
return std::make_shared<GeneralProtection>(0);
}
bool expandDown = false;
if (seg >= segment_idx::Es && seg <= segment_idx::Hs) {
if (!attr.writable && (mode == BaseMMU::Write || storeCheck)) {
DPRINTF(TLB, "Tried to write to unwritable segment.\n");
return std::make_shared<GeneralProtection>(0);
}
if (!attr.readable && mode == BaseMMU::Read) {
DPRINTF(TLB, "Tried to read from unreadble segment.\n");
return std::make_shared<GeneralProtection>(0);
}
expandDown = attr.expandDown;
}
Addr base = tc->readMiscRegNoEffect(misc_reg::segBase(seg));
Addr limit = tc->readMiscRegNoEffect(misc_reg::segLimit(seg));
Addr offset;
if (mode == BaseMMU::Execute)
offset = vaddr - base;
else
offset = (vaddr - base) & addrMask;
Addr endOffset = offset + req->getSize() - 1;
if (expandDown) {
DPRINTF(TLB, "Checking an expand down segment.\n");
warn_once("Expand down segments are untested.\n");
if (offset <= limit || endOffset <= limit)
return std::make_shared<GeneralProtection>(0);
} else {
if (offset > limit || endOffset > limit) {
DPRINTF(TLB, "Segment limit check failed, "
"offset = %#x limit = %#x.\n", offset, limit);
return std::make_shared<GeneralProtection>(0);
}
}
}
if (m5Reg.submode != SixtyFourBitMode && addrSize != 64)
vaddr &= mask(32);
// If paging is enabled, do the translation.
if (m5Reg.paging) {
DPRINTF(TLB, "Paging enabled.\n");
// The vaddr already has the segment base applied.
//Appending the pcid (last 12 bits of CR3) to the
//page aligned vaddr if pcide is set
CR4 cr4 = tc->readMiscRegNoEffect(misc_reg::Cr4);
Addr pageAlignedVaddr = vaddr & (~mask(X86ISA::PageShift));
CR3 cr3 = tc->readMiscRegNoEffect(misc_reg::Cr3);
uint64_t pcid;
if (cr4.pcide)
pcid = cr3.pcid;
else
pcid = 0x000;
pageAlignedVaddr = concAddrPcid(pageAlignedVaddr, pcid);
TlbEntry *entry = lookup(pageAlignedVaddr);
if (mode == BaseMMU::Read) {
stats.rdAccesses++;
} else {
stats.wrAccesses++;
}
if (!entry) {
DPRINTF(TLB, "Handling a TLB miss for "
"address %#x at pc %#x.\n",
vaddr, tc->pcState().instAddr());
if (mode == BaseMMU::Read) {
stats.rdMisses++;
} else {
stats.wrMisses++;
}
if (FullSystem) {
Fault fault = walker->start(tc, translation, req, mode);
if (timing || fault != NoFault) {
// This gets ignored in atomic mode.
delayedResponse = true;
return fault;
}
entry = lookup(pageAlignedVaddr);
assert(entry);
} else {
Process *p = tc->getProcessPtr();
const EmulationPageTable::Entry *pte =
p->pTable->lookup(vaddr);
if (!pte) {
return std::make_shared<PageFault>(vaddr, true, mode,
true, false);
} else {
Addr alignedVaddr = p->pTable->pageAlign(vaddr);
DPRINTF(TLB, "Mapping %#x to %#x\n", alignedVaddr,
pte->paddr);
entry = insert(alignedVaddr, TlbEntry(
p->pTable->pid(), alignedVaddr, pte->paddr,
pte->flags & EmulationPageTable::Uncacheable,
pte->flags & EmulationPageTable::ReadOnly),
pcid);
}
DPRINTF(TLB, "Miss was serviced.\n");
}
}
DPRINTF(TLB, "Entry found with paddr %#x, "
"doing protection checks.\n", entry->paddr);
// Do paging protection checks.
bool inUser = m5Reg.cpl == 3 && !(flags & CPL0FlagBit);
CR0 cr0 = tc->readMiscRegNoEffect(misc_reg::Cr0);
bool badWrite = (!entry->writable && (inUser || cr0.wp));
if ((inUser && !entry->user) ||
(mode == BaseMMU::Write && badWrite)) {
// The page must have been present to get into the TLB in
// the first place. We'll assume the reserved bits are
// fine even though we're not checking them.
return std::make_shared<PageFault>(vaddr, true, mode, inUser,
false);
}
if (storeCheck && badWrite) {
// This would fault if this were a write, so return a page
// fault that reflects that happening.
return std::make_shared<PageFault>(
vaddr, true, BaseMMU::Write, inUser, false);
}
Addr paddr = entry->paddr | (vaddr & mask(entry->logBytes));
DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, paddr);
req->setPaddr(paddr);
if (entry->uncacheable)
req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
} else {
//Use the address which already has segmentation applied.
DPRINTF(TLB, "Paging disabled.\n");
DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, vaddr);
req->setPaddr(vaddr);
}
} else {
// Real mode
DPRINTF(TLB, "In real mode.\n");
DPRINTF(TLB, "Translated %#x -> %#x.\n", vaddr, vaddr);
req->setPaddr(vaddr);
}
return finalizePhysical(req, tc, mode);
}
Fault
TLB::translateAtomic(const RequestPtr &req, ThreadContext *tc,
BaseMMU::Mode mode)
{
bool delayedResponse;
return TLB::translate(req, tc, NULL, mode, delayedResponse, false);
}
Fault
TLB::translateFunctional(const RequestPtr &req, ThreadContext *tc,
BaseMMU::Mode mode)
{
unsigned logBytes;
const Addr vaddr = req->getVaddr();
Addr addr = vaddr;
Addr paddr = 0;
if (FullSystem) {
Fault fault = walker->startFunctional(tc, addr, logBytes, mode);
if (fault != NoFault)
return fault;
paddr = insertBits(addr, logBytes - 1, 0, vaddr);
} else {
Process *process = tc->getProcessPtr();
const auto *pte = process->pTable->lookup(vaddr);
if (!pte && mode != BaseMMU::Execute) {
// Check if we just need to grow the stack.
if (process->fixupFault(vaddr)) {
// If we did, lookup the entry for the new page.
pte = process->pTable->lookup(vaddr);
}
}
if (!pte)
return std::make_shared<PageFault>(vaddr, true, mode, true, false);
paddr = pte->paddr | process->pTable->pageOffset(vaddr);
}
DPRINTF(TLB, "Translated (functional) %#x -> %#x.\n", vaddr, paddr);
req->setPaddr(paddr);
return NoFault;
}
void
TLB::translateTiming(const RequestPtr &req, ThreadContext *tc,
BaseMMU::Translation *translation, BaseMMU::Mode mode)
{
bool delayedResponse;
assert(translation);
Fault fault =
TLB::translate(req, tc, translation, mode, delayedResponse, true);
if (!delayedResponse)
translation->finish(fault, req, tc, mode);
else
translation->markDelayed();
}
Walker *
TLB::getWalker()
{
return walker;
}
TLB::TlbStats::TlbStats(statistics::Group *parent)
: statistics::Group(parent),
ADD_STAT(rdAccesses, statistics::units::Count::get(),
"TLB accesses on read requests"),
ADD_STAT(wrAccesses, statistics::units::Count::get(),
"TLB accesses on write requests"),
ADD_STAT(rdMisses, statistics::units::Count::get(),
"TLB misses on read requests"),
ADD_STAT(wrMisses, statistics::units::Count::get(),
"TLB misses on write requests")
{
}
void
TLB::serialize(CheckpointOut &cp) const
{
// Only store the entries in use.
uint32_t _size = size - freeList.size();
SERIALIZE_SCALAR(_size);
SERIALIZE_SCALAR(lruSeq);
uint32_t _count = 0;
for (uint32_t x = 0; x < size; x++) {
if (tlb[x].trieHandle != NULL)
tlb[x].serializeSection(cp, csprintf("Entry%d", _count++));
}
}
void
TLB::unserialize(CheckpointIn &cp)
{
// Do not allow to restore with a smaller tlb.
uint32_t _size;
UNSERIALIZE_SCALAR(_size);
if (_size > size) {
fatal("TLB size less than the one in checkpoint!");
}
UNSERIALIZE_SCALAR(lruSeq);
for (uint32_t x = 0; x < _size; x++) {
TlbEntry *newEntry = freeList.front();
freeList.pop_front();
newEntry->unserializeSection(cp, csprintf("Entry%d", x));
newEntry->trieHandle = trie.insert(newEntry->vaddr,
TlbEntryTrie::MaxBits - newEntry->logBytes, newEntry);
}
}
Port *
TLB::getTableWalkerPort()
{
return &walker->getPort("port");
}
} // namespace X86ISA
} // namespace gem5