lsq.hh revision 8975:7f36d4436074 
1/*
2 * Copyright (c) 2011 ARM Limited
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 * Copyright (c) 2004-2006 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Korey Sewell
41 */
42
43#ifndef __CPU_O3_LSQ_HH__
44#define __CPU_O3_LSQ_HH__
45
46#include <map>
47#include <queue>
48
49#include "cpu/o3/lsq_unit.hh"
50#include "cpu/inst_seq.hh"
51#include "mem/port.hh"
52#include "sim/sim_object.hh"
53
54struct DerivO3CPUParams;
55
56template <class Impl>
57class LSQ {
58  public:
59    typedef typename Impl::O3CPU O3CPU;
60    typedef typename Impl::DynInstPtr DynInstPtr;
61    typedef typename Impl::CPUPol::IEW IEW;
62    typedef typename Impl::CPUPol::LSQUnit LSQUnit;
63
64    /** SMT policy. */
65    enum LSQPolicy {
66        Dynamic,
67        Partitioned,
68        Threshold
69    };
70
71    /** Constructs an LSQ with the given parameters. */
72    LSQ(O3CPU *cpu_ptr, IEW *iew_ptr, DerivO3CPUParams *params);
73
74    /** Returns the name of the LSQ. */
75    std::string name() const;
76
77    /** Registers statistics of each LSQ unit. */
78    void regStats();
79
80    /** Sets the pointer to the list of active threads. */
81    void setActiveThreads(std::list<ThreadID> *at_ptr);
82    /** Switches out the LSQ. */
83    void switchOut();
84    /** Takes over execution from another CPU's thread. */
85    void takeOverFrom();
86
87    /** Number of entries needed for the given amount of threads.*/
88    int entryAmount(ThreadID num_threads);
89    void removeEntries(ThreadID tid);
90    /** Reset the max entries for each thread. */
91    void resetEntries();
92    /** Resize the max entries for a thread. */
93    void resizeEntries(unsigned size, ThreadID tid);
94
95    /** Ticks the LSQ. */
96    void tick();
97    /** Ticks a specific LSQ Unit. */
98    void tick(ThreadID tid)
99    { thread[tid].tick(); }
100
101    /** Inserts a load into the LSQ. */
102    void insertLoad(DynInstPtr &load_inst);
103    /** Inserts a store into the LSQ. */
104    void insertStore(DynInstPtr &store_inst);
105
106    /** Executes a load. */
107    Fault executeLoad(DynInstPtr &inst);
108
109    /** Executes a store. */
110    Fault executeStore(DynInstPtr &inst);
111
112    /**
113     * Commits loads up until the given sequence number for a specific thread.
114     */
115    void commitLoads(InstSeqNum &youngest_inst, ThreadID tid)
116    { thread[tid].commitLoads(youngest_inst); }
117
118    /**
119     * Commits stores up until the given sequence number for a specific thread.
120     */
121    void commitStores(InstSeqNum &youngest_inst, ThreadID tid)
122    { thread[tid].commitStores(youngest_inst); }
123
124    /**
125     * Attempts to write back stores until all cache ports are used or the
126     * interface becomes blocked.
127     */
128    void writebackStores();
129    /** Same as above, but only for one thread. */
130    void writebackStores(ThreadID tid);
131
132    /**
133     * Squash instructions from a thread until the specified sequence number.
134     */
135    void squash(const InstSeqNum &squashed_num, ThreadID tid)
136    { thread[tid].squash(squashed_num); }
137
138    /** Returns whether or not there was a memory ordering violation. */
139    bool violation();
140    /**
141     * Returns whether or not there was a memory ordering violation for a
142     * specific thread.
143     */
144    bool violation(ThreadID tid)
145    { return thread[tid].violation(); }
146
147    /** Returns if a load is blocked due to the memory system for a specific
148     *  thread.
149     */
150    bool loadBlocked(ThreadID tid)
151    { return thread[tid].loadBlocked(); }
152
153    bool isLoadBlockedHandled(ThreadID tid)
154    { return thread[tid].isLoadBlockedHandled(); }
155
156    void setLoadBlockedHandled(ThreadID tid)
157    { thread[tid].setLoadBlockedHandled(); }
158
159    /** Gets the instruction that caused the memory ordering violation. */
160    DynInstPtr getMemDepViolator(ThreadID tid)
161    { return thread[tid].getMemDepViolator(); }
162
163    /** Returns the head index of the load queue for a specific thread. */
164    int getLoadHead(ThreadID tid)
165    { return thread[tid].getLoadHead(); }
166
167    /** Returns the sequence number of the head of the load queue. */
168    InstSeqNum getLoadHeadSeqNum(ThreadID tid)
169    {
170        return thread[tid].getLoadHeadSeqNum();
171    }
172
173    /** Returns the head index of the store queue. */
174    int getStoreHead(ThreadID tid)
175    { return thread[tid].getStoreHead(); }
176
177    /** Returns the sequence number of the head of the store queue. */
178    InstSeqNum getStoreHeadSeqNum(ThreadID tid)
179    {
180        return thread[tid].getStoreHeadSeqNum();
181    }
182
183    /** Returns the number of instructions in all of the queues. */
184    int getCount();
185    /** Returns the number of instructions in the queues of one thread. */
186    int getCount(ThreadID tid)
187    { return thread[tid].getCount(); }
188
189    /** Returns the total number of loads in the load queue. */
190    int numLoads();
191    /** Returns the total number of loads for a single thread. */
192    int numLoads(ThreadID tid)
193    { return thread[tid].numLoads(); }
194
195    /** Returns the total number of stores in the store queue. */
196    int numStores();
197    /** Returns the total number of stores for a single thread. */
198    int numStores(ThreadID tid)
199    { return thread[tid].numStores(); }
200
201    /** Returns the total number of loads that are ready. */
202    int numLoadsReady();
203    /** Returns the number of loads that are ready for a single thread. */
204    int numLoadsReady(ThreadID tid)
205    { return thread[tid].numLoadsReady(); }
206
207    /** Returns the number of free entries. */
208    unsigned numFreeEntries();
209    /** Returns the number of free entries for a specific thread. */
210    unsigned numFreeEntries(ThreadID tid);
211
212    /** Returns if the LSQ is full (either LQ or SQ is full). */
213    bool isFull();
214    /**
215     * Returns if the LSQ is full for a specific thread (either LQ or SQ is
216     * full).
217     */
218    bool isFull(ThreadID tid);
219
220    /** Returns if any of the LQs are full. */
221    bool lqFull();
222    /** Returns if the LQ of a given thread is full. */
223    bool lqFull(ThreadID tid);
224
225    /** Returns if any of the SQs are full. */
226    bool sqFull();
227    /** Returns if the SQ of a given thread is full. */
228    bool sqFull(ThreadID tid);
229
230    /**
231     * Returns if the LSQ is stalled due to a memory operation that must be
232     * replayed.
233     */
234    bool isStalled();
235    /**
236     * Returns if the LSQ of a specific thread is stalled due to a memory
237     * operation that must be replayed.
238     */
239    bool isStalled(ThreadID tid);
240
241    /** Returns whether or not there are any stores to write back to memory. */
242    bool hasStoresToWB();
243
244    /** Returns whether or not a specific thread has any stores to write back
245     * to memory.
246     */
247    bool hasStoresToWB(ThreadID tid)
248    { return thread[tid].hasStoresToWB(); }
249
250    /** Returns the number of stores a specific thread has to write back. */
251    int numStoresToWB(ThreadID tid)
252    { return thread[tid].numStoresToWB(); }
253
254    /** Returns if the LSQ will write back to memory this cycle. */
255    bool willWB();
256    /** Returns if the LSQ of a specific thread will write back to memory this
257     * cycle.
258     */
259    bool willWB(ThreadID tid)
260    { return thread[tid].willWB(); }
261
262    /** Returns if the cache is currently blocked. */
263    bool cacheBlocked()
264    { return retryTid != InvalidThreadID; }
265
266    /** Sets the retry thread id, indicating that one of the LSQUnits
267     * tried to access the cache but the cache was blocked. */
268    void setRetryTid(ThreadID tid)
269    { retryTid = tid; }
270
271    /** Debugging function to print out all instructions. */
272    void dumpInsts();
273    /** Debugging function to print out instructions from a specific thread. */
274    void dumpInsts(ThreadID tid)
275    { thread[tid].dumpInsts(); }
276
277    /** Executes a read operation, using the load specified at the load
278     * index.
279     */
280    Fault read(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
281               uint8_t *data, int load_idx);
282
283    /** Executes a store operation, using the store specified at the store
284     * index.
285     */
286    Fault write(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
287                uint8_t *data, int store_idx);
288
289    /**
290     * Retry the previous send that failed.
291     */
292    void recvRetry();
293
294    /**
295     * Handles writing back and completing the load or store that has
296     * returned from memory.
297     *
298     * @param pkt Response packet from the memory sub-system
299     */
300    bool recvTimingResp(PacketPtr pkt);
301
302    void recvTimingSnoopReq(PacketPtr pkt);
303
304    /** The CPU pointer. */
305    O3CPU *cpu;
306
307    /** The IEW stage pointer. */
308    IEW *iewStage;
309
310  protected:
311    /** The LSQ policy for SMT mode. */
312    LSQPolicy lsqPolicy;
313
314    /** The LSQ units for individual threads. */
315    LSQUnit thread[Impl::MaxThreads];
316
317    /** List of Active Threads in System. */
318    std::list<ThreadID> *activeThreads;
319
320    /** Total Size of LQ Entries. */
321    unsigned LQEntries;
322    /** Total Size of SQ Entries. */
323    unsigned SQEntries;
324
325    /** Max LQ Size - Used to Enforce Sharing Policies. */
326    unsigned maxLQEntries;
327
328    /** Max SQ Size - Used to Enforce Sharing Policies. */
329    unsigned maxSQEntries;
330
331    /** Number of Threads. */
332    ThreadID numThreads;
333
334    /** The thread id of the LSQ Unit that is currently waiting for a
335     * retry. */
336    ThreadID retryTid;
337};
338
339template <class Impl>
340Fault
341LSQ<Impl>::read(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
342                uint8_t *data, int load_idx)
343{
344    ThreadID tid = req->threadId();
345
346    return thread[tid].read(req, sreqLow, sreqHigh, data, load_idx);
347}
348
349template <class Impl>
350Fault
351LSQ<Impl>::write(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
352                 uint8_t *data, int store_idx)
353{
354    ThreadID tid = req->threadId();
355
356    return thread[tid].write(req, sreqLow, sreqHigh, data, store_idx);
357}
358
359#endif // __CPU_O3_LSQ_HH__
360