gem5/src/arch/arm/vtophys.cc
Andreas Sandberg 34dcd90b61 arm: Fix broken page table permissions checks in remote GDB
The remote GDB interface currently doesn't check if translations are
valid before reading memory. This causes a panic when GDB tries to
access unmapped memory (e.g., when getting a stack trace). There are
two reasons for this: 1) The function used to check for valid
translations (virtvalid()) doesn't work and panics on invalid
translations. 2) The method in the GDB interface used to test if a
translation is valid (RemoteGDB::acc) always returns true regardless
of the return from virtvalid().

This changeset fixes both of these issues.
2015-03-02 04:00:27 -05:00

114 lines
4.2 KiB
C++

/*
* Copyright (c) 2010, 2012-2013 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) 2002-2005 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
* Nathan Binkert
* Stephen Hines
*/
#include <string>
#include "arch/arm/faults.hh"
#include "arch/arm/table_walker.hh"
#include "arch/arm/tlb.hh"
#include "arch/arm/vtophys.hh"
#include "base/chunk_generator.hh"
#include "base/trace.hh"
#include "cpu/thread_context.hh"
#include "mem/fs_translating_port_proxy.hh"
using namespace std;
using namespace ArmISA;
Addr
ArmISA::vtophys(Addr vaddr)
{
fatal("VTOPHYS: Can't convert vaddr to paddr on ARM without a thread context");
}
static std::pair<bool, Addr>
try_translate(ThreadContext *tc, Addr addr)
{
Fault fault;
// Set up a functional memory Request to pass to the TLB
// to get it to translate the vaddr to a paddr
Request req(0, addr, 64, 0x40, -1, 0, 0, 0);
ArmISA::TLB *tlb;
// Check the TLBs for a translation
// It's possible that there is a valid translation in the tlb
// that is no loger valid in the page table in memory
// so we need to check here first
//
// Calling translateFunctional invokes a table-walk if required
// so we should always succeed
tlb = static_cast<ArmISA::TLB*>(tc->getDTBPtr());
fault = tlb->translateFunctional(&req, tc, BaseTLB::Read, TLB::NormalTran);
if (fault == NoFault)
return std::make_pair(true, req.getPaddr());
tlb = static_cast<ArmISA::TLB*>(tc->getITBPtr());
fault = tlb->translateFunctional(&req, tc, BaseTLB::Read, TLB::NormalTran);
if (fault == NoFault)
return std::make_pair(true, req.getPaddr());
return std::make_pair(false, 0);
}
Addr
ArmISA::vtophys(ThreadContext *tc, Addr addr)
{
const std::pair<bool, Addr> translation(try_translate(tc, addr));
if (translation.first)
return translation.second;
else
panic("Table walkers support functional accesses. We should never get here\n");
}
bool
ArmISA::virtvalid(ThreadContext *tc, Addr vaddr)
{
const std::pair<bool, Addr> translation(try_translate(tc, vaddr));
return translation.first;
}