unsigned getSize() const { assert(flags.isSet(VALID_SIZE)); return size; }
Addr getOffset(int blkSize) const { return getAddr() & (Addr)(blkSize - 1); }
+ /**
+ * It has been determined that the SC packet should successfully update
+ * memory. Therefore, convert this SC packet to a normal write.
+ */
+ void
+ convertScToWrite()
+ {
+ assert(isLLSC());
+ assert(isWrite());
+ cmd = MemCmd::WriteReq;
+ }
+
+ /**
+ * When ruby is in use, Ruby will monitor the cache line and thus M5
+ * phys memory should treat LL ops as normal reads.
+ */
+ void
+ convertLlToRead()
+ {
+ assert(isLLSC());
+ assert(isRead());
+ cmd = MemCmd::ReadReq;
+ }
+
/**
* Constructor. Note that a Request object must be constructed
* first, but the Requests's physical address and size fields need
Read_Write, desc="Read/Write";
Invalid, desc="Invalid";
NotPresent, desc="NotPresent";
- OnHold, desc="Holding a place in dnuca cache";
ReadUpgradingToWrite, desc="Read only, but trying to get Read/Write";
Stale, desc="local L1 has a modified copy, assume L2 copy is stale data";
}
Issued, desc="The sequencer successfully issued the request";
BufferFull, desc="Can not issue because the sequencer is full";
Aliased, desc="This request aliased with a currently outstanding request";
- LlscFailed, desc="The write failed in the Load-Link Store-Conditional pair";
NULL, desc="";
}
lookup(address).m_Permission = new_perm;
Index cacheSet = addressToCacheSet(address);
int loc = findTagInSet(cacheSet, address);
- if (new_perm != AccessPermission_Read_Write) {
+ if ((new_perm == AccessPermission_Invalid) ||
+ (new_perm == AccessPermission_NotPresent) ||
+ (new_perm == AccessPermission_Stale)) {
DPRINTF(RubyCache, "Permission clearing lock for addr: %x\n", address);
m_locked[cacheSet][loc] = -1;
}
// Submit the ruby request
RequestStatus requestStatus = ruby_port->makeRequest(ruby_request);
- // If the request successfully issued or the SC request completed because
- // exclusive permission was lost, then we should return true.
+ // If the request successfully issued then we should return true.
// Otherwise, we need to delete the senderStatus we just created and return
// false.
- if ((requestStatus == RequestStatus_Issued) ||
- (requestStatus == RequestStatus_LlscFailed)) {
-
- // The communicate to M5 whether the SC command succeeded by seting the
- // packet's extra data.
- if (pkt->isLLSC() && pkt->isWrite()) {
- if (requestStatus == RequestStatus_LlscFailed) {
- DPRINTF(MemoryAccess, "SC failed and request completed\n");
- pkt->req->setExtraData(0);
- } else {
- pkt->req->setExtraData(1);
- }
- }
+ if (requestStatus == RequestStatus_Issued) {
return true;
}
{
bool needsResponse = pkt->needsResponse();
+ //
+ // All responses except failed SC operations access M5 physical memory
+ //
+ bool accessPhysMem = true;
+
+ if (pkt->isLLSC()) {
+ if (pkt->isWrite()) {
+ if (pkt->req->getExtraData() != 0) {
+ //
+ // Successful SC packets convert to normal writes
+ //
+ pkt->convertScToWrite();
+ } else {
+ //
+ // Failed SC packets don't access physical memory and thus
+ // the RubyPort itself must convert it to a response.
+ //
+ accessPhysMem = false;
+ pkt->makeAtomicResponse();
+ }
+ } else {
+ //
+ // All LL packets convert to normal loads so that M5 PhysMem does
+ // not lock the blocks.
+ //
+ pkt->convertLlToRead();
+ }
+ }
DPRINTF(MemoryAccess, "Hit callback needs response %d\n", needsResponse);
- ruby_port->physMemPort->sendAtomic(pkt);
+ if (accessPhysMem) {
+ ruby_port->physMemPort->sendAtomic(pkt);
+ }
// turn packet around to go back to requester if response expected
if (needsResponse) {
#include "mem/ruby/system/CacheMemory.hh"
#include "mem/ruby/system/Sequencer.hh"
#include "mem/ruby/system/System.hh"
+#include "mem/packet.hh"
#include "params/RubySequencer.hh"
using namespace std;
markRemoved();
}
+void
+Sequencer::handleLlscWrites(const Address& address, SequencerRequest* request)
+{
+ if (request->ruby_request.type == RubyRequestType_Locked_Write) {
+ if (!m_dataCache_ptr->isLocked(address, m_version)) {
+ //
+ // For failed SC requests, indicate the failure to the cpu by
+ // setting the extra data to zero.
+ //
+ request->ruby_request.pkt->req->setExtraData(0);
+ } else {
+ //
+ // For successful SC requests, indicate the success to the cpu by
+ // setting the extra data to one.
+ //
+ request->ruby_request.pkt->req->setExtraData(1);
+ }
+ m_dataCache_ptr->clearLocked(address);
+ } else if (request->ruby_request.type == RubyRequestType_Locked_Read) {
+ //
+ // Note: To fully follow Alpha LLSC semantics, should the LL clear any
+ // previously locked cache lines?
+ //
+ m_dataCache_ptr->setLocked(address, m_version);
+ } else if (m_dataCache_ptr->isLocked(address, m_version)) {
+ //
+ // Normal writes should clear the locked address
+ //
+ m_dataCache_ptr->clearLocked(address);
+ }
+}
+
void
Sequencer::writeCallback(const Address& address, DataBlock& data)
{
(request->ruby_request.type == RubyRequestType_Locked_Read) ||
(request->ruby_request.type == RubyRequestType_Locked_Write));
- if (request->ruby_request.type == RubyRequestType_Locked_Read) {
- m_dataCache_ptr->setLocked(address, m_version);
- } else if (request->ruby_request.type == RubyRequestType_RMW_Read) {
+ //
+ // For Alpha, properly handle LL, SC, and write requests with respect to
+ // locked cache blocks.
+ //
+ handleLlscWrites(address, request);
+
+ if (request->ruby_request.type == RubyRequestType_RMW_Read) {
m_controller->blockOnQueue(address, m_mandatory_q_ptr);
} else if (request->ruby_request.type == RubyRequestType_RMW_Write) {
m_controller->unblock(address);
return RequestStatus_NULL;
}
- if (request.type == RubyRequestType_Locked_Write) {
- // NOTE: it is OK to check the locked flag here as the
- // mandatory queue will be checked first ensuring that nothing
- // comes between checking the flag and servicing the store.
-
- Address line_addr = line_address(Address(request.paddr));
- if (!m_dataCache_ptr->isLocked(line_addr, m_version)) {
- removeRequest(srequest);
- if (Debug::getProtocolTrace()) {
- g_system_ptr->getProfiler()->
- profileTransition("Seq", m_version,
- Address(request.paddr),
- "", "SC Fail", "",
- RubyRequestType_to_string(request.type));
- }
- return RequestStatus_LlscFailed;
- } else {
- m_dataCache_ptr->clearLocked(line_addr);
- }
- }
issueRequest(request);
// TODO: issue hardware prefetches here
bool insertRequest(SequencerRequest* request);
+ void handleLlscWrites(const Address& address, SequencerRequest* request);
// Private copy constructor and assignment operator
Sequencer(const Sequencer& obj);
projects / gem5.git / commitdiff