gem5/util/statetrace/arch/arm/tracechild.cc
2011-04-15 10:44:06 -07:00

255 lines
7.4 KiB
C++

/*
* Copyright (c) 2010 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) 2006-2009 The Regents of The University of Michigan
* 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
* Gabe Black
*/
#include <stdint.h>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <iostream>
#include "arch/arm/tracechild.hh"
using namespace std;
ARMTraceChild::ARMTraceChild()
{
foundMvn = false;
for (int x = 0; x < numregs; x++) {
memset(&regs, 0, sizeof(regs));
memset(&oldregs, 0, sizeof(regs));
regDiffSinceUpdate[x] = false;
}
}
bool
ARMTraceChild::sendState(int socket)
{
uint32_t regVal = 0;
uint32_t message[numregs + 1];
int pos = 1;
message[0] = 0;
for (int x = 0; x < numregs; x++) {
if (regDiffSinceUpdate[x]) {
message[0] = message[0] | (1 << x);
message[pos++] = getRegVal(x);
}
}
size_t sent = 0;
size_t toSend = pos * sizeof(message[0]);
uint8_t *messagePtr = (uint8_t *)message;
while (toSend != 0) {
sent = write(socket, messagePtr, toSend);
if (sent == -1) {
cerr << "Write failed! " << strerror(errno) << endl;
tracing = false;
return false;
}
toSend -= sent;
messagePtr += sent;
}
return true;
}
uint32_t
ARMTraceChild::getRegs(user_regs &myregs, int num)
{
assert(num < numregs && num >= 0);
return myregs.uregs[num];
}
bool
ARMTraceChild::update(int pid)
{
oldregs = regs;
if (ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0) {
cerr << "update: " << strerror(errno) << endl;
return false;
}
for (unsigned int x = 0; x < numregs; x++)
regDiffSinceUpdate[x] = (getRegVal(x) != getOldRegVal(x));
return true;
}
int64_t
ARMTraceChild::getRegVal(int num)
{
return getRegs(regs, num);
}
int64_t
ARMTraceChild::getOldRegVal(int num)
{
return getRegs(oldregs, num);
}
ostream &
ARMTraceChild::outputStartState(ostream & os)
{
uint32_t sp = getSP();
uint32_t pc = getPC();
uint32_t highestInfo = 0;
char obuf[1024];
sprintf(obuf, "Initial stack pointer = 0x%08x\n", sp);
os << obuf;
sprintf(obuf, "Initial program counter = 0x%08x\n", pc);
os << obuf;
//Output the argument count
int32_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%08x: Argc = 0x%08x\n", sp, cargc);
os << obuf;
sp += 4;
//Output argv pointers
int argCount = 0;
int32_t cargv;
do {
cargv = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%08x: argv[%d] = 0x%08x\n",
sp, argCount++, cargv);
if(cargv)
if(highestInfo < cargv)
highestInfo = cargv;
os << obuf;
sp += 4;
} while(cargv);
//Output the envp pointers
int envCount = 0;
uint32_t cenvp;
do {
cenvp = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%08x: envp[%d] = 0x%08x\n",
sp, envCount++, cenvp);
os << obuf;
sp += 4;
} while(cenvp);
uint32_t auxType, auxVal;
do {
auxType = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sp += 4;
auxVal = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sp += 4;
sprintf(obuf, "0x%08x: Auxiliary vector = {0x%08x, 0x%08x}\n",
sp - 8, auxType, auxVal);
os << obuf;
} while(auxType != 0 || auxVal != 0);
//Print out the argument strings, environment strings, and file name.
string current;
uint32_t buf;
uint32_t currentStart = sp;
bool clearedInitialPadding = false;
do {
buf = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
char * cbuf = (char *)&buf;
for (int x = 0; x < sizeof(uint32_t); x++) {
if (cbuf[x])
current += cbuf[x];
else {
sprintf(obuf, "0x%08x: \"%s\"\n",
currentStart, current.c_str());
os << obuf;
current = "";
currentStart = sp + x + 1;
}
}
sp += 4;
clearedInitialPadding = clearedInitialPadding || buf != 0;
} while(!clearedInitialPadding || buf != 0 || sp <= highestInfo);
return os;
}
bool
ARMTraceChild::step()
{
const uint32_t bkpt_inst = 0xe7f001f0;
uint32_t lr = getRegVal(14);
uint32_t pc = getPC();
uint32_t lrOp, subsOp;
char obuf[128];
bool patch = false;
// Since ARM uses software breakpoints behind the scenes, they don't work
// in read only areas like the page of routines provided by the kernel. The
// link register generally holds the address the process wants to the
// kernel to return to after it's done, so we'll install a software
// breakpoint there.
//
// Calls into the kernel user page always follow the form:
// MVN ...
// <possible MOV lr,...>
// SUB PC, ...
//
// So we look for this pattern and set a breakpoint on the LR at the SUB
// instruction.
subsOp = ptrace(PTRACE_PEEKDATA, pid, pc, 0);
if ((subsOp & 0xFFFF0FFF) == 0xe3e00a0f)
foundMvn = true;
if (foundMvn && ((subsOp & 0xFFF0F000) == 0xe240f000)) {
foundMvn = false;
lrOp = ptrace(PTRACE_PEEKDATA, pid, lr, 0);
ptrace(PTRACE_POKEDATA, pid, lr, bkpt_inst);
patch = true;
}
ptraceSingleStep();
if (patch)
ptrace(PTRACE_POKEDATA, pid, lr, lrOp);
}
TraceChild *
genTraceChild()
{
return new ARMTraceChild;
}