1/*
2 * Copyright (c) 2012-2014,2016-2018 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) 2003-2005 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: Erik Hallnor
41 *          Ron Dreslinski
42 */
43
44/**
45 * @file
46 * Declaration of a common base class for cache tagstore objects.
47 */
48
49#ifndef __MEM_CACHE_TAGS_BASE_HH__
50#define __MEM_CACHE_TAGS_BASE_HH__
51
52#include <cassert>
53#include <cstdint>
54#include <functional>
55#include <string>
56
57#include "base/callback.hh"
58#include "base/logging.hh"
59#include "base/statistics.hh"
60#include "base/types.hh"
61#include "mem/cache/cache_blk.hh"
62#include "mem/packet.hh"
63#include "params/BaseTags.hh"
64#include "sim/clocked_object.hh"
65
66class System;
67class IndexingPolicy;
68class ReplaceableEntry;
69
70/**
71 * A common base class of Cache tagstore objects.
72 */
73class BaseTags : public ClockedObject
74{
75  protected:
76    /** The block size of the cache. */
77    const unsigned blkSize;
78    /** Mask out all bits that aren't part of the block offset. */
79    const Addr blkMask;
80    /** The size of the cache. */
81    const unsigned size;
82    /** The tag lookup latency of the cache. */
83    const Cycles lookupLatency;
84
85    /** System we are currently operating in. */
86    System *system;
87
88    /** Indexing policy */
89    BaseIndexingPolicy *indexingPolicy;
90
91    /**
92     * The number of tags that need to be touched to meet the warmup
93     * percentage.
94     */
95    const unsigned warmupBound;
96    /** Marked true when the cache is warmed up. */
97    bool warmedUp;
98
99    /** the number of blocks in the cache */
100    const unsigned numBlocks;
101
102    /** The data blocks, 1 per cache block. */
103    std::unique_ptr<uint8_t[]> dataBlks;
104
105    // Statistics
106    /**
107     * TODO: It would be good if these stats were acquired after warmup.
108     * @addtogroup CacheStatistics
109     * @{
110     */
111
112    /** Per cycle average of the number of tags that hold valid data. */
113    Stats::Average tagsInUse;
114
115    /** The total number of references to a block before it is replaced. */
116    Stats::Scalar totalRefs;
117
118    /**
119     * The number of reference counts sampled. This is different from
120     * replacements because we sample all the valid blocks when the simulator
121     * exits.
122     */
123    Stats::Scalar sampledRefs;
124
125    /**
126     * Average number of references to a block before is was replaced.
127     * @todo This should change to an average stat once we have them.
128     */
129    Stats::Formula avgRefs;
130
131    /** The cycle that the warmup percentage was hit. 0 on failure. */
132    Stats::Scalar warmupCycle;
133
134    /** Average occupancy of each requestor using the cache */
135    Stats::AverageVector occupancies;
136
137    /** Average occ % of each requestor using the cache */
138    Stats::Formula avgOccs;
139
140    /** Occupancy of each context/cpu using the cache */
141    Stats::Vector occupanciesTaskId;
142
143    /** Occupancy of each context/cpu using the cache */
144    Stats::Vector2d ageTaskId;
145
146    /** Occ % of each context/cpu using the cache */
147    Stats::Formula percentOccsTaskId;
148
149    /** Number of tags consulted over all accesses. */
150    Stats::Scalar tagAccesses;
151    /** Number of data blocks consulted over all accesses. */
152    Stats::Scalar dataAccesses;
153
154    /**
155     * @}
156     */
157
158  public:
159    typedef BaseTagsParams Params;
160    BaseTags(const Params *p);
161
162    /**
163     * Destructor.
164     */
165    virtual ~BaseTags() {}
166
167    /**
168     * Initialize blocks. Must be overriden by every subclass that uses
169     * a block type different from its parent's, as the current Python
170     * code generation does not allow templates.
171     */
172    virtual void tagsInit() = 0;
173
174    /**
175     * Register local statistics.
176     */
177    void regStats();
178
179    /**
180     * Average in the reference count for valid blocks when the simulation
181     * exits.
182     */
183    void cleanupRefs();
184
185    /**
186     * Computes stats just prior to dump event
187     */
188    void computeStats();
189
190    /**
191     * Print all tags used
192     */
193    std::string print();
194
195    /**
196     * Finds the block in the cache without touching it.
197     *
198     * @param addr The address to look for.
199     * @param is_secure True if the target memory space is secure.
200     * @return Pointer to the cache block.
201     */
202    virtual CacheBlk *findBlock(Addr addr, bool is_secure) const;
203
204    /**
205     * Find a block given set and way.
206     *
207     * @param set The set of the block.
208     * @param way The way of the block.
209     * @return The block.
210     */
211    virtual ReplaceableEntry* findBlockBySetAndWay(int set, int way) const;
212
213    /**
214     * Align an address to the block size.
215     * @param addr the address to align.
216     * @return The block address.
217     */
218    Addr blkAlign(Addr addr) const
219    {
220        return addr & ~blkMask;
221    }
222
223    /**
224     * Calculate the block offset of an address.
225     * @param addr the address to get the offset of.
226     * @return the block offset.
227     */
228    int extractBlkOffset(Addr addr) const
229    {
230        return (addr & blkMask);
231    }
232
233    /**
234     * Limit the allocation for the cache ways.
235     * @param ways The maximum number of ways available for replacement.
236     */
237    virtual void setWayAllocationMax(int ways)
238    {
239        panic("This tag class does not implement way allocation limit!\n");
240    }
241
242    /**
243     * Get the way allocation mask limit.
244     * @return The maximum number of ways available for replacement.
245     */
246    virtual int getWayAllocationMax() const
247    {
248        panic("This tag class does not implement way allocation limit!\n");
249        return -1;
250    }
251
252    /**
253     * This function updates the tags when a block is invalidated
254     *
255     * @param blk A valid block to invalidate.
256     */
257    virtual void invalidate(CacheBlk *blk)
258    {
259        assert(blk);
260        assert(blk->isValid());
261
262        occupancies[blk->srcMasterId]--;
263        totalRefs += blk->refCount;
264        sampledRefs++;
265
266        blk->invalidate();
267    }
268
269    /**
270     * Find replacement victim based on address. If the address requires
271     * blocks to be evicted, their locations are listed for eviction. If a
272     * conventional cache is being used, the list only contains the victim.
273     * However, if using sector or compressed caches, the victim is one of
274     * the blocks to be evicted, but its location is the only one that will
275     * be assigned to the newly allocated block associated to this address.
276     * @sa insertBlock
277     *
278     * @param addr Address to find a victim for.
279     * @param is_secure True if the target memory space is secure.
280     * @param size Size, in bits, of new block to allocate.
281     * @param evict_blks Cache blocks to be evicted.
282     * @return Cache block to be replaced.
283     */
284    virtual CacheBlk* findVictim(Addr addr, const bool is_secure,
285                                 const std::size_t size,
286                                 std::vector<CacheBlk*>& evict_blks) const = 0;
287
288    /**
289     * Access block and update replacement data. May not succeed, in which case
290     * nullptr is returned. This has all the implications of a cache access and
291     * should only be used as such. Returns the tag lookup latency as a side
292     * effect.
293     *
294     * @param addr The address to find.
295     * @param is_secure True if the target memory space is secure.
296     * @param lat The latency of the tag lookup.
297     * @return Pointer to the cache block if found.
298     */
299    virtual CacheBlk* accessBlock(Addr addr, bool is_secure, Cycles &lat) = 0;
300
301    /**
302     * Generate the tag from the given address.
303     *
304     * @param addr The address to get the tag from.
305     * @return The tag of the address.
306     */
307    virtual Addr extractTag(const Addr addr) const;
308
309    /**
310     * Insert the new block into the cache and update stats.
311     *
312     * @param pkt Packet holding the address to update
313     * @param blk The block to update.
314     */
315    virtual void insertBlock(const PacketPtr pkt, CacheBlk *blk);
316
317    /**
318     * Regenerate the block address.
319     *
320     * @param block The block.
321     * @return the block address.
322     */
323    virtual Addr regenerateBlkAddr(const CacheBlk* blk) const = 0;
324
325    /**
326     * Visit each block in the tags and apply a visitor
327     *
328     * The visitor should be a std::function that takes a cache block
329     * reference as its parameter.
330     *
331     * @param visitor Visitor to call on each block.
332     */
333    virtual void forEachBlk(std::function<void(CacheBlk &)> visitor) = 0;
334
335    /**
336     * Find if any of the blocks satisfies a condition
337     *
338     * The visitor should be a std::function that takes a cache block
339     * reference as its parameter. The visitor will terminate the
340     * traversal early if the condition is satisfied.
341     *
342     * @param visitor Visitor to call on each block.
343     */
344    virtual bool anyBlk(std::function<bool(CacheBlk &)> visitor) = 0;
345
346  private:
347    /**
348     * Update the reference stats using data from the input block
349     *
350     * @param blk The input block
351     */
352    void cleanupRefsVisitor(CacheBlk &blk);
353
354    /**
355     * Update the occupancy and age stats using data from the input block
356     *
357     * @param blk The input block
358     */
359    void computeStatsVisitor(CacheBlk &blk);
360};
361
362class BaseTagsCallback : public Callback
363{
364    BaseTags *tags;
365  public:
366    BaseTagsCallback(BaseTags *t) : tags(t) {}
367    virtual void process() { tags->cleanupRefs(); };
368};
369
370class BaseTagsDumpCallback : public Callback
371{
372    BaseTags *tags;
373  public:
374    BaseTagsDumpCallback(BaseTags *t) : tags(t) {}
375    virtual void process() { tags->computeStats(); };
376};
377
378#endif //__MEM_CACHE_TAGS_BASE_HH__
379