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/*
* Copyright (c) 2012-2013,2017 ARM Limited
* 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 The Regents of The University of Michigan
* Copyright (c) 2007-2008 The Florida State University
* 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: Ali Saidi
* Steve Reinhardt
* Stephen Hines
*/
#ifndef __ARCH_ARM_LOCKED_MEM_HH__
#define __ARCH_ARM_LOCKED_MEM_HH__
/**
* @file
*
* ISA-specific helper functions for locked memory accesses.
*/
#include "arch/arm/miscregs.hh"
#include "arch/arm/isa_traits.hh"
#include "debug/LLSC.hh"
#include "mem/packet.hh"
#include "mem/request.hh"
namespace ArmISA
{
template <class XC>
inline void
handleLockedSnoop(XC *xc, PacketPtr pkt, Addr cacheBlockMask)
{
// Should only every see invalidations / direct writes
assert(pkt->isInvalidate() || pkt->isWrite());
DPRINTF(LLSC,"%s: handling snoop for address: %#x locked: %d\n",
xc->getCpuPtr()->name(),pkt->getAddr(),
xc->readMiscReg(MISCREG_LOCKFLAG));
if (!xc->readMiscReg(MISCREG_LOCKFLAG))
return;
Addr locked_addr = xc->readMiscReg(MISCREG_LOCKADDR) & cacheBlockMask;
// If no caches are attached, the snoop address always needs to be masked
Addr snoop_addr = pkt->getAddr() & cacheBlockMask;
DPRINTF(LLSC,"%s: handling snoop for address: %#x locked addr: %#x\n",
xc->getCpuPtr()->name(),snoop_addr, locked_addr);
if (locked_addr == snoop_addr) {
DPRINTF(LLSC,"%s: address match, clearing lock and signaling sev\n",
xc->getCpuPtr()->name());
xc->setMiscReg(MISCREG_LOCKFLAG, false);
// Implement ARMv8 WFE/SEV semantics
xc->setMiscReg(MISCREG_SEV_MAILBOX, true);
xc->getCpuPtr()->wakeup(xc->threadId());
}
}
template <class XC>
inline void
handleLockedRead(XC *xc, Request *req)
{
xc->setMiscReg(MISCREG_LOCKADDR, req->getPaddr());
xc->setMiscReg(MISCREG_LOCKFLAG, true);
DPRINTF(LLSC,"%s: Placing address %#x in monitor\n", xc->getCpuPtr()->name(),
req->getPaddr());
}
template <class XC>
inline void
handleLockedSnoopHit(XC *xc)
{
DPRINTF(LLSC,"%s: handling snoop lock hit address: %#x\n",
xc->getCpuPtr()->name(), xc->readMiscReg(MISCREG_LOCKADDR));
xc->setMiscReg(MISCREG_LOCKFLAG, false);
xc->setMiscReg(MISCREG_SEV_MAILBOX, true);
}
template <class XC>
inline bool
handleLockedWrite(XC *xc, Request *req, Addr cacheBlockMask)
{
if (req->isSwap())
return true;
DPRINTF(LLSC,"%s: handling locked write for address %#x in monitor\n",
xc->getCpuPtr()->name(), req->getPaddr());
// Verify that the lock flag is still set and the address
// is correct
bool lock_flag = xc->readMiscReg(MISCREG_LOCKFLAG);
Addr lock_addr = xc->readMiscReg(MISCREG_LOCKADDR) & cacheBlockMask;
if (!lock_flag || (req->getPaddr() & cacheBlockMask) != lock_addr) {
// Lock flag not set or addr mismatch in CPU;
// don't even bother sending to memory system
req->setExtraData(0);
xc->setMiscReg(MISCREG_LOCKFLAG, false);
DPRINTF(LLSC,"%s: clearing lock flag in handle locked write\n",
xc->getCpuPtr()->name());
// the rest of this code is not architectural;
// it's just a debugging aid to help detect
// livelock by warning on long sequences of failed
// store conditionals
int stCondFailures = xc->readStCondFailures();
stCondFailures++;
xc->setStCondFailures(stCondFailures);
if (stCondFailures % 100000 == 0) {
warn("context %d: %d consecutive "
"store conditional failures\n",
xc->contextId(), stCondFailures);
}
// store conditional failed already, so don't issue it to mem
return false;
}
return true;
}
template <class XC>
inline void
globalClearExclusive(XC *xc)
{
// A spinlock would typically include a Wait For Event (WFE) to
// conserve energy. The ARMv8 architecture specifies that an event
// is automatically generated when clearing the exclusive monitor
// to wake up the processor in WFE.
DPRINTF(LLSC,"Clearing lock and signaling sev\n");
xc->setMiscReg(MISCREG_LOCKFLAG, false);
// Implement ARMv8 WFE/SEV semantics
xc->setMiscReg(MISCREG_SEV_MAILBOX, true);
xc->getCpuPtr()->wakeup(xc->threadId());
}
} // namespace ArmISA
#endif
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