abstract_mem.hh revision 13853:7ec6a25d2bc1 
1/*
2 * Copyright (c) 2012 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) 2001-2005 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
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38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Ron Dreslinski
41 *          Andreas Hansson
42 */
43
44/**
45 * @file
46 * AbstractMemory declaration
47 */
48
49#ifndef __MEM_ABSTRACT_MEMORY_HH__
50#define __MEM_ABSTRACT_MEMORY_HH__
51
52#include "mem/backdoor.hh"
53#include "mem/mem_object.hh"
54#include "params/AbstractMemory.hh"
55#include "sim/stats.hh"
56
57
58class System;
59
60/**
61 * Locked address class that represents a physical address and a
62 * context id.
63 */
64class LockedAddr {
65
66  private:
67
68    // on alpha, minimum LL/SC granularity is 16 bytes, so lower
69    // bits need to masked off.
70    static const Addr Addr_Mask = 0xf;
71
72  public:
73
74    // locked address
75    Addr addr;
76
77    // locking hw context
78    const ContextID contextId;
79
80    static Addr mask(Addr paddr) { return (paddr & ~Addr_Mask); }
81
82    // check for matching execution context
83    bool matchesContext(const RequestPtr &req) const
84    {
85        return (contextId == req->contextId());
86    }
87
88    LockedAddr(const RequestPtr &req) : addr(mask(req->getPaddr())),
89                                        contextId(req->contextId())
90    {}
91
92    // constructor for unserialization use
93    LockedAddr(Addr _addr, int _cid) : addr(_addr), contextId(_cid)
94    {}
95};
96
97/**
98 * An abstract memory represents a contiguous block of physical
99 * memory, with an associated address range, and also provides basic
100 * functionality for reading and writing this memory without any
101 * timing information. It is a MemObject since any subclass must have
102 * at least one slave port.
103 */
104class AbstractMemory : public MemObject
105{
106  protected:
107
108    // Address range of this memory
109    AddrRange range;
110
111    // Pointer to host memory used to implement this memory
112    uint8_t* pmemAddr;
113
114    // Backdoor to access this memory.
115    MemBackdoor backdoor;
116
117    // Enable specific memories to be reported to the configuration table
118    const bool confTableReported;
119
120    // Should the memory appear in the global address map
121    const bool inAddrMap;
122
123    // Should KVM map this memory for the guest
124    const bool kvmMap;
125
126    std::list<LockedAddr> lockedAddrList;
127
128    // helper function for checkLockedAddrs(): we really want to
129    // inline a quick check for an empty locked addr list (hopefully
130    // the common case), and do the full list search (if necessary) in
131    // this out-of-line function
132    bool checkLockedAddrList(PacketPtr pkt);
133
134    // Record the address of a load-locked operation so that we can
135    // clear the execution context's lock flag if a matching store is
136    // performed
137    void trackLoadLocked(PacketPtr pkt);
138
139    // Compare a store address with any locked addresses so we can
140    // clear the lock flag appropriately.  Return value set to 'false'
141    // if store operation should be suppressed (because it was a
142    // conditional store and the address was no longer locked by the
143    // requesting execution context), 'true' otherwise.  Note that
144    // this method must be called on *all* stores since even
145    // non-conditional stores must clear any matching lock addresses.
146    bool writeOK(PacketPtr pkt) {
147        const RequestPtr &req = pkt->req;
148        if (lockedAddrList.empty()) {
149            // no locked addrs: nothing to check, store_conditional fails
150            bool isLLSC = pkt->isLLSC();
151            if (isLLSC) {
152                req->setExtraData(0);
153            }
154            return !isLLSC; // only do write if not an sc
155        } else {
156            // iterate over list...
157            return checkLockedAddrList(pkt);
158        }
159    }
160
161    /** Number of total bytes read from this memory */
162    Stats::Vector bytesRead;
163    /** Number of instruction bytes read from this memory */
164    Stats::Vector bytesInstRead;
165    /** Number of bytes written to this memory */
166    Stats::Vector bytesWritten;
167    /** Number of read requests */
168    Stats::Vector numReads;
169    /** Number of write requests */
170    Stats::Vector numWrites;
171    /** Number of other requests */
172    Stats::Vector numOther;
173    /** Read bandwidth from this memory */
174    Stats::Formula bwRead;
175    /** Read bandwidth from this memory */
176    Stats::Formula bwInstRead;
177    /** Write bandwidth from this memory */
178    Stats::Formula bwWrite;
179    /** Total bandwidth from this memory */
180    Stats::Formula bwTotal;
181
182    /** Pointor to the System object.
183     * This is used for getting the number of masters in the system which is
184     * needed when registering stats
185     */
186    System *_system;
187
188
189  private:
190
191    // Prevent copying
192    AbstractMemory(const AbstractMemory&);
193
194    // Prevent assignment
195    AbstractMemory& operator=(const AbstractMemory&);
196
197  public:
198
199    typedef AbstractMemoryParams Params;
200
201    AbstractMemory(const Params* p);
202    virtual ~AbstractMemory() {}
203
204    /**
205     * Initialise this memory.
206     */
207    void init() override;
208
209    /**
210     * See if this is a null memory that should never store data and
211     * always return zero.
212     *
213     * @return true if null
214     */
215    bool isNull() const { return params()->null; }
216
217    /**
218     * Set the host memory backing store to be used by this memory
219     * controller.
220     *
221     * @param pmem_addr Pointer to a segment of host memory
222     */
223    void setBackingStore(uint8_t* pmem_addr);
224
225    /**
226     * Get the list of locked addresses to allow checkpointing.
227     */
228    const std::list<LockedAddr>& getLockedAddrList() const
229    { return lockedAddrList; }
230
231    /**
232     * Add a locked address to allow for checkpointing.
233     */
234    void addLockedAddr(LockedAddr addr) { lockedAddrList.push_back(addr); }
235
236    /** read the system pointer
237     * Implemented for completeness with the setter
238     * @return pointer to the system object */
239    System* system() const { return _system; }
240
241    /** Set the system pointer on this memory
242     * This can't be done via a python parameter because the system needs
243     * pointers to all the memories and the reverse would create a cycle in the
244     * object graph. An init() this is set.
245     * @param sys system pointer to set
246     */
247    void system(System *sys) { _system = sys; }
248
249    const Params *
250    params() const
251    {
252        return dynamic_cast<const Params *>(_params);
253    }
254
255    /**
256     * Get the address range
257     *
258     * @return a single contigous address range
259     */
260    AddrRange getAddrRange() const;
261
262    /**
263     * Get the memory size.
264     *
265     * @return the size of the memory
266     */
267    uint64_t size() const { return range.size(); }
268
269    /**
270     * Get the start address.
271     *
272     * @return the start address of the memory
273     */
274    Addr start() const { return range.start(); }
275
276    /**
277     *  Should this memory be passed to the kernel and part of the OS
278     *  physical memory layout.
279     *
280     * @return if this memory is reported
281     */
282    bool isConfReported() const { return confTableReported; }
283
284    /**
285     * Some memories are used as shadow memories or should for other
286     * reasons not be part of the global address map.
287     *
288     * @return if this memory is part of the address map
289     */
290    bool isInAddrMap() const { return inAddrMap; }
291
292    /**
293     * When shadow memories are in use, KVM may want to make one or the other,
294     * but cannot map both into the guest address space.
295     *
296     * @return if this memory should be mapped into the KVM guest address space
297     */
298    bool isKvmMap() const { return kvmMap; }
299
300    /**
301     * Perform an untimed memory access and update all the state
302     * (e.g. locked addresses) and statistics accordingly. The packet
303     * is turned into a response if required.
304     *
305     * @param pkt Packet performing the access
306     */
307    void access(PacketPtr pkt);
308
309    /**
310     * Perform an untimed memory read or write without changing
311     * anything but the memory itself. No stats are affected by this
312     * access. In addition to normal accesses this also facilitates
313     * print requests.
314     *
315     * @param pkt Packet performing the access
316     */
317    void functionalAccess(PacketPtr pkt);
318
319    /**
320     * Register Statistics
321     */
322    void regStats() override;
323
324};
325
326#endif //__MEM_ABSTRACT_MEMORY_HH__
327