locked_mem.hh revision 12218:8c5db15dc8e7 
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) 2006-2007 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: Steve Reinhardt
41 */
42
43#ifndef __ARCH_MIPS_LOCKED_MEM_HH__
44#define __ARCH_MIPS_LOCKED_MEM_HH__
45
46/**
47 * @file
48 *
49 * ISA-specific helper functions for locked memory accesses.
50 */
51
52#include "arch/registers.hh"
53#include "base/misc.hh"
54#include "base/trace.hh"
55#include "debug/LLSC.hh"
56#include "mem/packet.hh"
57#include "mem/request.hh"
58
59namespace MipsISA
60{
61template <class XC>
62inline void
63handleLockedSnoop(XC *xc, PacketPtr pkt, Addr cacheBlockMask)
64{
65    if (!xc->readMiscReg(MISCREG_LLFLAG))
66        return;
67
68    Addr locked_addr = xc->readMiscReg(MISCREG_LLADDR) & cacheBlockMask;
69    Addr snoop_addr = pkt->getAddr() & cacheBlockMask;
70
71    if (locked_addr == snoop_addr)
72        xc->setMiscReg(MISCREG_LLFLAG, false);
73}
74
75
76template <class XC>
77inline void
78handleLockedRead(XC *xc, Request *req)
79{
80    xc->setMiscReg(MISCREG_LLADDR, req->getPaddr() & ~0xf);
81    xc->setMiscReg(MISCREG_LLFLAG, true);
82    DPRINTF(LLSC, "[cid:%i]: Load-Link Flag Set & Load-Link"
83                  " Address set to %x.\n",
84            req->contextId(), req->getPaddr() & ~0xf);
85}
86
87template <class XC>
88inline void
89handleLockedSnoopHit(XC *xc)
90{
91}
92
93template <class XC>
94inline bool
95handleLockedWrite(XC *xc, Request *req, Addr cacheBlockMask)
96{
97    if (req->isUncacheable()) {
98        // Funky Turbolaser mailbox access...don't update
99        // result register (see stq_c in decoder.isa)
100        req->setExtraData(2);
101    } else {
102        // standard store conditional
103        bool lock_flag = xc->readMiscReg(MISCREG_LLFLAG);
104        Addr lock_addr = xc->readMiscReg(MISCREG_LLADDR);
105
106        if (!lock_flag || (req->getPaddr() & ~0xf) != lock_addr) {
107            // Lock flag not set or addr mismatch in CPU;
108            // don't even bother sending to memory system
109            req->setExtraData(0);
110            xc->setMiscReg(MISCREG_LLFLAG, false);
111
112            // the rest of this code is not architectural;
113            // it's just a debugging aid to help detect
114            // livelock by warning on long sequences of failed
115            // store conditionals
116            int stCondFailures = xc->readStCondFailures();
117            stCondFailures++;
118            xc->setStCondFailures(stCondFailures);
119            if (stCondFailures % 100000 == 0) {
120                warn("%i: context %d: %d consecutive "
121                     "store conditional failures\n",
122                     curTick(), xc->contextId(), stCondFailures);
123            }
124
125            if (!lock_flag){
126                DPRINTF(LLSC, "[cid:%i]: Lock Flag Set, "
127                              "Store Conditional Failed.\n",
128                        req->contextId());
129            } else if ((req->getPaddr() & ~0xf) != lock_addr) {
130                DPRINTF(LLSC, "[cid:%i]: Load-Link Address Mismatch, "
131                              "Store Conditional Failed.\n",
132                        req->contextId());
133            }
134            // store conditional failed already, so don't issue it to mem
135            return false;
136        }
137    }
138
139    return true;
140}
141
142template <class XC>
143inline void
144globalClearExclusive(XC *xc)
145{
146    xc->getCpuPtr()->wakeup(xc->threadId());
147}
148
149} // namespace MipsISA
150
151#endif
152