1/*
2 * Copyright (c) 2018 Inria
3 * Copyright (c) 2012-2014,2017 ARM Limited
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) 2003-2005,2014 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: Daniel Carvalho
42 *          Erik Hallnor
43 */
44
45/**
46 * @file
47 * Declaration of a common framework for indexing policies.
48 */
49
50#ifndef __MEM_CACHE_INDEXING_POLICIES_BASE_HH__
51#define __MEM_CACHE_INDEXING_POLICIES_BASE_HH__
52
53#include <vector>
54
55#include "params/BaseIndexingPolicy.hh"
56#include "sim/sim_object.hh"
57
58class ReplaceableEntry;
59
60/**
61 * A common base class for indexing table locations. Classes that inherit
62 * from it determine hash functions that should be applied based on the set
63 * and way. These functions are then applied to re-map the original values.
64 * @sa  \ref gem5MemorySystem "gem5 Memory System"
65 */
66class BaseIndexingPolicy : public SimObject
67{
68  protected:
69    /**
70     * The associativity.
71     */
72    const unsigned assoc;
73
74    /**
75     * The number of sets in the cache.
76     */
77    const uint32_t numSets;
78
79    /**
80     * The amount to shift the address to get the set.
81     */
82    const int setShift;
83
84    /**
85     * Mask out all bits that aren't part of the set index.
86     */
87    const unsigned setMask;
88
89    /**
90     * The cache sets.
91     */
92    std::vector<std::vector<ReplaceableEntry*>> sets;
93
94    /**
95     * The amount to shift the address to get the tag.
96     */
97    const int tagShift;
98
99  public:
100    /**
101     * Convenience typedef.
102     */
103    typedef BaseIndexingPolicyParams Params;
104
105    /**
106     * Construct and initialize this policy.
107     */
108    BaseIndexingPolicy(const Params *p);
109
110    /**
111     * Destructor.
112     */
113    ~BaseIndexingPolicy() {};
114
115    /**
116     * Associate a pointer to an entry to its physical counterpart.
117     *
118     * @param entry The entry pointer.
119     * @param index An unique index for the entry.
120     */
121    void setEntry(ReplaceableEntry* entry, const uint64_t index);
122
123    /**
124     * Get an entry based on its set and way. All entries must have been set
125     * already before calling this function.
126     *
127     * @param set The set of the desired entry.
128     * @param way The way of the desired entry.
129     * @return entry The entry pointer.
130     */
131    ReplaceableEntry* getEntry(const uint32_t set, const uint32_t way) const;
132
133    /**
134     * Generate the tag from the given address.
135     *
136     * @param addr The address to get the tag from.
137     * @return The tag of the address.
138     */
139    Addr extractTag(const Addr addr) const;
140
141    /**
142     * Find all possible entries for insertion and replacement of an address.
143     * Should be called immediately before ReplacementPolicy's findVictim()
144     * not to break cache resizing.
145     *
146     * @param addr The addr to a find possible entries for.
147     * @return The possible entries.
148     */
149    virtual std::vector<ReplaceableEntry*> getPossibleEntries(const Addr addr)
150                                                                    const = 0;
151
152    /**
153     * Regenerate an entry's address from its tag and assigned indexing bits.
154     *
155     * @param tag The tag bits.
156     * @param entry The entry.
157     * @return the entry's original address.
158     */
159    virtual Addr regenerateAddr(const Addr tag, const ReplaceableEntry* entry)
160                                                                    const = 0;
161};
162
163#endif //__MEM_CACHE_INDEXING_POLICIES_BASE_HH__
164