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/*
* Copyright (c) 2006 The Regents of The University of Michigan
* Copyright (c) 2007-2008 The Florida State University
* Copyright (c) 2009 The University of Edinburgh
* Copyright (c) 2012 ARM Limited
* Copyright (c) 2014-2015 Sven Karlsson
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2006-2007 The Regents of The University of Michigan
* Copyright (c) 2016 The University of Virginia
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Steve Reinhardt
* Alec Roelke
*/
#ifndef __ARCH_RISCV_LOCKED_MEM_HH__
#define __ARCH_RISCV_LOCKED_MEM_HH__
#include <stack>
#include "arch/registers.hh"
#include "base/logging.hh"
#include "base/trace.hh"
#include "debug/LLSC.hh"
#include "mem/packet.hh"
#include "mem/request.hh"
/*
* ISA-specific helper functions for locked memory accesses.
*/
namespace RiscvISA
{
const int WARN_FAILURE = 10000;
// RISC-V allows multiple locks per hart, but each SC has to unlock the most
// recent one, so we use a stack here.
extern std::stack<Addr> locked_addrs;
template <class XC> inline void
handleLockedSnoop(XC *xc, PacketPtr pkt, Addr cacheBlockMask)
{
if (locked_addrs.empty())
return;
Addr snoop_addr = pkt->getAddr() & cacheBlockMask;
DPRINTF(LLSC, "Locked snoop on address %x.\n", snoop_addr);
if ((locked_addrs.top() & cacheBlockMask) == snoop_addr)
locked_addrs.pop();
}
template <class XC> inline void
handleLockedRead(XC *xc, Request *req)
{
locked_addrs.push(req->getPaddr() & ~0xF);
DPRINTF(LLSC, "[cid:%d]: Reserved address %x.\n",
req->contextId(), req->getPaddr() & ~0xF);
}
template <class XC> inline void
handleLockedSnoopHit(XC *xc)
{}
template <class XC> inline bool
handleLockedWrite(XC *xc, Request *req, Addr cacheBlockMask)
{
// Normally RISC-V uses zero to indicate success and nonzero to indicate
// failure (right now only 1 is reserved), but in gem5 zero indicates
// failure and one indicates success, so here we conform to that (it should
// be switched in the instruction's implementation)
DPRINTF(LLSC, "[cid:%d]: locked_addrs empty? %s.\n", req->contextId(),
locked_addrs.empty() ? "yes" : "no");
if (!locked_addrs.empty()) {
DPRINTF(LLSC, "[cid:%d]: addr = %x.\n", req->contextId(),
req->getPaddr() & ~0xF);
DPRINTF(LLSC, "[cid:%d]: last locked addr = %x.\n", req->contextId(),
locked_addrs.top());
}
if (locked_addrs.empty()
|| locked_addrs.top() != ((req->getPaddr() & ~0xF))) {
req->setExtraData(0);
int stCondFailures = xc->readStCondFailures();
xc->setStCondFailures(++stCondFailures);
if (stCondFailures % WARN_FAILURE == 0) {
warn("%i: context %d: %d consecutive SC failures.\n",
curTick(), xc->contextId(), stCondFailures);
}
return false;
}
if (req->isUncacheable()) {
req->setExtraData(2);
}
return true;
}
template <class XC>
inline void
globalClearExclusive(XC *xc)
{
xc->getCpuPtr()->wakeup(xc->threadId());
}
} // namespace RiscvISA
#endif // __ARCH_RISCV_LOCKED_MEM_HH__
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