gem5/util/statetrace/arch/tracechild_amd64.cc

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/*
* Copyright (c) 2007 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: Gabe Black
*/
#include <iostream>
#include <iomanip>
#include <errno.h>
#include <sys/ptrace.h>
#include <stdint.h>
#include "tracechild_amd64.hh"
using namespace std;
char * AMD64TraceChild::regNames[numregs] = {
//GPRs
"rax", "rbx", "rcx", "rdx",
//Index registers
"rsi", "rdi",
//Base pointer and stack pointer
"rbp", "rsp",
//New 64 bit mode registers
"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
//Segmentation registers
"cs", "ds", "es", "fs", "gs", "ss", "fs_base", "gs_base",
//PC
"rip",
//Flags
"eflags"};
bool AMD64TraceChild::sendState(int socket)
{
uint64_t regVal = 0;
for(int x = 0; x <= R15; x++)
{
regVal = getRegVal(x);
if(write(socket, &regVal, sizeof(regVal)) == -1)
{
cerr << "Write failed! " << strerror(errno) << endl;
tracing = false;
return false;
}
}
regVal = getRegVal(RIP);
if(write(socket, &regVal, sizeof(regVal)) == -1)
{
cerr << "Write failed! " << strerror(errno) << endl;
tracing = false;
return false;
}
return true;
}
int64_t AMD64TraceChild::getRegs(user_regs_struct & myregs, int num)
{
assert(num < numregs && num >= 0);
switch(num)
{
//GPRs
case RAX: return myregs.rax;
case RBX: return myregs.rbx;
case RCX: return myregs.rcx;
case RDX: return myregs.rdx;
//Index registers
case RSI: return myregs.rsi;
case RDI: return myregs.rdi;
//Base pointer and stack pointer
case RBP: return myregs.rbp;
case RSP: return myregs.rsp;
//New 64 bit mode registers
case R8: return myregs.r8;
case R9: return myregs.r9;
case R10: return myregs.r10;
case R11: return myregs.r11;
case R12: return myregs.r12;
case R13: return myregs.r13;
case R14: return myregs.r14;
case R15: return myregs.r15;
//Segmentation registers
case CS: return myregs.cs;
case DS: return myregs.ds;
case ES: return myregs.es;
case FS: return myregs.fs;
case GS: return myregs.gs;
case SS: return myregs.ss;
case FS_BASE: return myregs.fs_base;
case GS_BASE: return myregs.gs_base;
//PC
case RIP: return myregs.rip;
//Flags
case EFLAGS: return myregs.eflags;
default:
assert(0);
return 0;
}
}
bool AMD64TraceChild::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;
}
AMD64TraceChild::AMD64TraceChild()
{
for(unsigned int x = 0; x < numregs; x++)
regDiffSinceUpdate[x] = false;
}
int64_t AMD64TraceChild::getRegVal(int num)
{
return getRegs(regs, num);
}
int64_t AMD64TraceChild::getOldRegVal(int num)
{
return getRegs(oldregs, num);
}
char * AMD64TraceChild::printReg(int num)
{
sprintf(printBuffer, "0x%08X", getRegVal(num));
return printBuffer;
}
ostream & AMD64TraceChild::outputStartState(ostream & os)
{
uint64_t sp = getSP();
uint64_t pc = getPC();
uint64_t highestInfo = 0;
char obuf[1024];
sprintf(obuf, "Initial stack pointer = 0x%016llx\n", sp);
os << obuf;
sprintf(obuf, "Initial program counter = 0x%016llx\n", pc);
os << obuf;
//Output the argument count
uint64_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%016llx: Argc = 0x%016llx\n", sp, cargc);
os << obuf;
sp += 8;
//Output argv pointers
int argCount = 0;
uint64_t cargv;
do
{
cargv = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%016llx: argv[%d] = 0x%016llx\n",
sp, argCount++, cargv);
if(cargv)
if(highestInfo < cargv)
highestInfo = cargv;
os << obuf;
sp += 8;
} while(cargv);
//Output the envp pointers
int envCount = 0;
uint64_t cenvp;
do
{
cenvp = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sprintf(obuf, "0x%016llx: envp[%d] = 0x%016llx\n",
sp, envCount++, cenvp);
os << obuf;
sp += 8;
} while(cenvp);
uint64_t auxType, auxVal;
do
{
auxType = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sp += 8;
auxVal = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
sp += 8;
sprintf(obuf, "0x%016llx: Auxiliary vector = {0x%016llx, 0x%016llx}\n",
sp - 16, auxType, auxVal);
os << obuf;
} while(auxType != 0 || auxVal != 0);
//Print out the argument strings, environment strings, and file name.
string current;
uint64_t buf;
uint64_t currentStart = sp;
bool clearedInitialPadding = false;
do
{
buf = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
char * cbuf = (char *)&buf;
for(int x = 0; x < sizeof(uint64_t); x++)
{
if(cbuf[x])
current += cbuf[x];
else
{
sprintf(obuf, "0x%016llx: \"%s\"\n",
currentStart, current.c_str());
os << obuf;
current = "";
currentStart = sp + x + 1;
}
}
sp += 8;
clearedInitialPadding = clearedInitialPadding || buf != 0;
} while(!clearedInitialPadding || buf != 0 || sp <= highestInfo);
return os;
}
uint64_t AMD64TraceChild::findSyscall()
{
uint64_t rip = getPC();
bool foundOpcode = false;
bool twoByteOpcode = false;
for(;;)
{
uint64_t buf = ptrace(PTRACE_PEEKDATA, pid, rip, 0);
for(int i = 0; i < sizeof(uint64_t); i++)
{
unsigned char byte = buf & 0xFF;
if(!foundOpcode)
{
if(!(byte == 0x66 || //operand override
byte == 0x67 || //address override
byte == 0x2E || //cs
byte == 0x3E || //ds
byte == 0x26 || //es
byte == 0x64 || //fs
byte == 0x65 || //gs
byte == 0x36 || //ss
byte == 0xF0 || //lock
byte == 0xF2 || //repe
byte == 0xF3 || //repne
(byte >= 0x40 && byte <= 0x4F) // REX
))
{
foundOpcode = true;
}
}
if(foundOpcode)
{
if(twoByteOpcode)
{
//SYSCALL or SYSENTER
if(byte == 0x05 || byte == 0x34)
return rip + 1;
else
return 0;
}
if(!twoByteOpcode)
{
if(byte == 0xCC) // INT3
return rip + 1;
else if(byte == 0xCD) // INT with byte immediate
return rip + 2;
else if(byte == 0x0F) // two byte opcode prefix
twoByteOpcode = true;
else
return 0;
}
}
buf >>= 8;
rip++;
}
}
}
bool AMD64TraceChild::step()
{
uint64_t ripAfterSyscall = findSyscall();
if(ripAfterSyscall)
{
//Get the original contents of memory
uint64_t buf = ptrace(PTRACE_PEEKDATA, pid, ripAfterSyscall, 0);
//Patch the first two bytes of the memory immediately after this with
//jmp -2. Either single stepping will take over before this
//instruction, leaving the rip where it should be, or it will take
//over after this instruction, -still- leaving the rip where it should
//be.
uint64_t newBuf = (buf & ~0xFFFF) | 0xFEEB;
//Write the patched memory to the processes address space
ptrace(PTRACE_POKEDATA, pid, ripAfterSyscall, newBuf);
//Step and hit it
ptraceSingleStep();
//Put things back to the way they started
ptrace(PTRACE_POKEDATA, pid, ripAfterSyscall, buf);
}
else
{
//Get all the way past repe and repne string instructions in one shot.
uint64_t newPC, origPC = getPC();
do
{
ptraceSingleStep();
newPC = getPC();
} while(newPC == origPC);
}
}
TraceChild * genTraceChild()
{
return new AMD64TraceChild;
}