lsq.hh revision 10259 
1/*
2 * Copyright (c) 2011-2012 ARM Limited
3 * Copyright (c) 2013 Advanced Micro Devices, Inc.
4 * All rights reserved
5 *
6 * The license below extends only to copyright in the software and shall
7 * not be construed as granting a license to any other intellectual
8 * property including but not limited to intellectual property relating
9 * to a hardware implementation of the functionality of the software
10 * licensed hereunder.  You may use the software subject to the license
11 * terms below provided that you ensure that this notice is replicated
12 * unmodified and in its entirety in all distributions of the software,
13 * modified or unmodified, in source code or in binary form.
14 *
15 * Copyright (c) 2004-2006 The Regents of The University of Michigan
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Korey Sewell
42 */
43
44#ifndef __CPU_O3_LSQ_HH__
45#define __CPU_O3_LSQ_HH__
46
47#include <map>
48#include <queue>
49
50#include "cpu/o3/lsq_unit.hh"
51#include "cpu/inst_seq.hh"
52#include "mem/port.hh"
53#include "sim/sim_object.hh"
54
55struct DerivO3CPUParams;
56
57template <class Impl>
58class LSQ {
59  public:
60    typedef typename Impl::O3CPU O3CPU;
61    typedef typename Impl::DynInstPtr DynInstPtr;
62    typedef typename Impl::CPUPol::IEW IEW;
63    typedef typename Impl::CPUPol::LSQUnit LSQUnit;
64
65    /** SMT policy. */
66    enum LSQPolicy {
67        Dynamic,
68        Partitioned,
69        Threshold
70    };
71
72    /** Constructs an LSQ with the given parameters. */
73    LSQ(O3CPU *cpu_ptr, IEW *iew_ptr, DerivO3CPUParams *params);
74    ~LSQ() {
75        if (thread) delete [] thread;
76    }
77
78    /** Returns the name of the LSQ. */
79    std::string name() const;
80
81    /** Registers statistics of each LSQ unit. */
82    void regStats();
83
84    /** Sets the pointer to the list of active threads. */
85    void setActiveThreads(std::list<ThreadID> *at_ptr);
86
87    /** Perform sanity checks after a drain. */
88    void drainSanityCheck() const;
89    /** Has the LSQ drained? */
90    bool isDrained() const;
91    /** Takes over execution from another CPU's thread. */
92    void takeOverFrom();
93
94    /** Number of entries needed for the given amount of threads.*/
95    int entryAmount(ThreadID num_threads);
96    void removeEntries(ThreadID tid);
97    /** Reset the max entries for each thread. */
98    void resetEntries();
99    /** Resize the max entries for a thread. */
100    void resizeEntries(unsigned size, ThreadID tid);
101
102    /** Ticks the LSQ. */
103    void tick();
104    /** Ticks a specific LSQ Unit. */
105    void tick(ThreadID tid)
106    { thread[tid].tick(); }
107
108    /** Inserts a load into the LSQ. */
109    void insertLoad(DynInstPtr &load_inst);
110    /** Inserts a store into the LSQ. */
111    void insertStore(DynInstPtr &store_inst);
112
113    /** Executes a load. */
114    Fault executeLoad(DynInstPtr &inst);
115
116    /** Executes a store. */
117    Fault executeStore(DynInstPtr &inst);
118
119    /**
120     * Commits loads up until the given sequence number for a specific thread.
121     */
122    void commitLoads(InstSeqNum &youngest_inst, ThreadID tid)
123    { thread[tid].commitLoads(youngest_inst); }
124
125    /**
126     * Commits stores up until the given sequence number for a specific thread.
127     */
128    void commitStores(InstSeqNum &youngest_inst, ThreadID tid)
129    { thread[tid].commitStores(youngest_inst); }
130
131    /**
132     * Attempts to write back stores until all cache ports are used or the
133     * interface becomes blocked.
134     */
135    void writebackStores();
136    /** Same as above, but only for one thread. */
137    void writebackStores(ThreadID tid);
138
139    /**
140     * Squash instructions from a thread until the specified sequence number.
141     */
142    void squash(const InstSeqNum &squashed_num, ThreadID tid)
143    { thread[tid].squash(squashed_num); }
144
145    /** Returns whether or not there was a memory ordering violation. */
146    bool violation();
147    /**
148     * Returns whether or not there was a memory ordering violation for a
149     * specific thread.
150     */
151    bool violation(ThreadID tid)
152    { return thread[tid].violation(); }
153
154    /** Returns if a load is blocked due to the memory system for a specific
155     *  thread.
156     */
157    bool loadBlocked(ThreadID tid)
158    { return thread[tid].loadBlocked(); }
159
160    bool isLoadBlockedHandled(ThreadID tid)
161    { return thread[tid].isLoadBlockedHandled(); }
162
163    void setLoadBlockedHandled(ThreadID tid)
164    { thread[tid].setLoadBlockedHandled(); }
165
166    /** Gets the instruction that caused the memory ordering violation. */
167    DynInstPtr getMemDepViolator(ThreadID tid)
168    { return thread[tid].getMemDepViolator(); }
169
170    /** Returns the head index of the load queue for a specific thread. */
171    int getLoadHead(ThreadID tid)
172    { return thread[tid].getLoadHead(); }
173
174    /** Returns the sequence number of the head of the load queue. */
175    InstSeqNum getLoadHeadSeqNum(ThreadID tid)
176    {
177        return thread[tid].getLoadHeadSeqNum();
178    }
179
180    /** Returns the head index of the store queue. */
181    int getStoreHead(ThreadID tid)
182    { return thread[tid].getStoreHead(); }
183
184    /** Returns the sequence number of the head of the store queue. */
185    InstSeqNum getStoreHeadSeqNum(ThreadID tid)
186    {
187        return thread[tid].getStoreHeadSeqNum();
188    }
189
190    /** Returns the number of instructions in all of the queues. */
191    int getCount();
192    /** Returns the number of instructions in the queues of one thread. */
193    int getCount(ThreadID tid)
194    { return thread[tid].getCount(); }
195
196    /** Returns the total number of loads in the load queue. */
197    int numLoads();
198    /** Returns the total number of loads for a single thread. */
199    int numLoads(ThreadID tid)
200    { return thread[tid].numLoads(); }
201
202    /** Returns the total number of stores in the store queue. */
203    int numStores();
204    /** Returns the total number of stores for a single thread. */
205    int numStores(ThreadID tid)
206    { return thread[tid].numStores(); }
207
208    /** Returns the number of free load entries. */
209    unsigned numFreeLoadEntries();
210
211    /** Returns the number of free store entries. */
212    unsigned numFreeStoreEntries();
213
214    /** Returns the number of free entries for a specific thread. */
215    unsigned numFreeEntries(ThreadID tid);
216
217    /** Returns the number of free entries in the LQ for a specific thread. */
218    unsigned numFreeLoadEntries(ThreadID tid);
219
220    /** Returns the number of free entries in the SQ for a specific thread. */
221    unsigned numFreeStoreEntries(ThreadID tid);
222
223    /** Returns if the LSQ is full (either LQ or SQ is full). */
224    bool isFull();
225    /**
226     * Returns if the LSQ is full for a specific thread (either LQ or SQ is
227     * full).
228     */
229    bool isFull(ThreadID tid);
230
231    /** Returns if the LSQ is empty (both LQ and SQ are empty). */
232    bool isEmpty() const;
233    /** Returns if all of the LQs are empty. */
234    bool lqEmpty() const;
235    /** Returns if all of the SQs are empty. */
236    bool sqEmpty() const;
237
238    /** Returns if any of the LQs are full. */
239    bool lqFull();
240    /** Returns if the LQ of a given thread is full. */
241    bool lqFull(ThreadID tid);
242
243    /** Returns if any of the SQs are full. */
244    bool sqFull();
245    /** Returns if the SQ of a given thread is full. */
246    bool sqFull(ThreadID tid);
247
248    /**
249     * Returns if the LSQ is stalled due to a memory operation that must be
250     * replayed.
251     */
252    bool isStalled();
253    /**
254     * Returns if the LSQ of a specific thread is stalled due to a memory
255     * operation that must be replayed.
256     */
257    bool isStalled(ThreadID tid);
258
259    /** Returns whether or not there are any stores to write back to memory. */
260    bool hasStoresToWB();
261
262    /** Returns whether or not a specific thread has any stores to write back
263     * to memory.
264     */
265    bool hasStoresToWB(ThreadID tid)
266    { return thread[tid].hasStoresToWB(); }
267
268    /** Returns the number of stores a specific thread has to write back. */
269    int numStoresToWB(ThreadID tid)
270    { return thread[tid].numStoresToWB(); }
271
272    /** Returns if the LSQ will write back to memory this cycle. */
273    bool willWB();
274    /** Returns if the LSQ of a specific thread will write back to memory this
275     * cycle.
276     */
277    bool willWB(ThreadID tid)
278    { return thread[tid].willWB(); }
279
280    /** Returns if the cache is currently blocked. */
281    bool cacheBlocked() const
282    { return retryTid != InvalidThreadID; }
283
284    /** Sets the retry thread id, indicating that one of the LSQUnits
285     * tried to access the cache but the cache was blocked. */
286    void setRetryTid(ThreadID tid)
287    { retryTid = tid; }
288
289    /** Debugging function to print out all instructions. */
290    void dumpInsts() const;
291    /** Debugging function to print out instructions from a specific thread. */
292    void dumpInsts(ThreadID tid) const
293    { thread[tid].dumpInsts(); }
294
295    /** Executes a read operation, using the load specified at the load
296     * index.
297     */
298    Fault read(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
299               uint8_t *data, int load_idx);
300
301    /** Executes a store operation, using the store specified at the store
302     * index.
303     */
304    Fault write(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
305                uint8_t *data, int store_idx);
306
307    /**
308     * Retry the previous send that failed.
309     */
310    void recvRetry();
311
312    /**
313     * Handles writing back and completing the load or store that has
314     * returned from memory.
315     *
316     * @param pkt Response packet from the memory sub-system
317     */
318    bool recvTimingResp(PacketPtr pkt);
319
320    void recvTimingSnoopReq(PacketPtr pkt);
321
322    /** The CPU pointer. */
323    O3CPU *cpu;
324
325    /** The IEW stage pointer. */
326    IEW *iewStage;
327
328  protected:
329    /** The LSQ policy for SMT mode. */
330    LSQPolicy lsqPolicy;
331
332    /** The LSQ units for individual threads. */
333    LSQUnit *thread;
334
335    /** List of Active Threads in System. */
336    std::list<ThreadID> *activeThreads;
337
338    /** Total Size of LQ Entries. */
339    unsigned LQEntries;
340    /** Total Size of SQ Entries. */
341    unsigned SQEntries;
342
343    /** Max LQ Size - Used to Enforce Sharing Policies. */
344    unsigned maxLQEntries;
345
346    /** Max SQ Size - Used to Enforce Sharing Policies. */
347    unsigned maxSQEntries;
348
349    /** Number of Threads. */
350    ThreadID numThreads;
351
352    /** The thread id of the LSQ Unit that is currently waiting for a
353     * retry. */
354    ThreadID retryTid;
355};
356
357template <class Impl>
358Fault
359LSQ<Impl>::read(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
360                uint8_t *data, int load_idx)
361{
362    ThreadID tid = req->threadId();
363
364    return thread[tid].read(req, sreqLow, sreqHigh, data, load_idx);
365}
366
367template <class Impl>
368Fault
369LSQ<Impl>::write(RequestPtr req, RequestPtr sreqLow, RequestPtr sreqHigh,
370                 uint8_t *data, int store_idx)
371{
372    ThreadID tid = req->threadId();
373
374    return thread[tid].write(req, sreqLow, sreqHigh, data, store_idx);
375}
376
377#endif // __CPU_O3_LSQ_HH__
378