util/statetrace/arch/amd64/tracechild.cc - public/gem5 - Git at Google

 /*
  * 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 <sys/ptrace.h>
 #include <stdint.h>

 #include <cerrno>
 #include <cstring>
 #include <iomanip>
 #include <iostream>

 #include "arch/amd64/tracechild.hh"

 using namespace std;

 bool
 AMD64TraceChild::sendState(int socket)
 {
     uint64_t regVal64 = 0;
     uint32_t regVal32 = 0;
     for (int x = 0; x <= R15; x++) {
         regVal64 = getRegVal(x);
         if (write(socket, &regVal64, sizeof(regVal64)) == -1) {
             cerr << "Write failed! " << strerror(errno) << endl;
             tracing = false;
             return false;
         }
     }
     regVal64 = getRegVal(RIP);
     if (write(socket, &regVal64, sizeof(regVal64)) == -1) {
         cerr << "Write failed! " << strerror(errno) << endl;
         tracing = false;
         return false;
     }
     for (int x = MMX0_0; x <= MMX7_1; x++) {
         regVal32 = getRegVal(x);
         if (write(socket, &regVal32, sizeof(regVal32)) == -1) {
             cerr << "Write failed! " << strerror(errno) << endl;
             tracing = false;
             return false;
         }
     }
     for (int x = XMM0_0; x <= XMM15_3; x++) {
         regVal32 = getRegVal(x);
         if (write(socket, &regVal32, sizeof(regVal32)) == -1) {
             cerr << "Write failed! " << strerror(errno) << endl;
             tracing = false;
             return false;
         }
     }
     return true;
 }

 int64_t
 AMD64TraceChild::getRegs(user_regs_struct & myregs,
         user_fpregs_struct & myfpregs, 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;
       //MMX
       case MMX0_0: return myfpregs.st_space[0];
       case MMX0_1: return myfpregs.st_space[1];
       case MMX1_0: return myfpregs.st_space[2];
       case MMX1_1: return myfpregs.st_space[3];
       case MMX2_0: return myfpregs.st_space[4];
       case MMX2_1: return myfpregs.st_space[5];
       case MMX3_0: return myfpregs.st_space[6];
       case MMX3_1: return myfpregs.st_space[7];
       case MMX4_0: return myfpregs.st_space[8];
       case MMX4_1: return myfpregs.st_space[9];
       case MMX5_0: return myfpregs.st_space[10];
       case MMX5_1: return myfpregs.st_space[11];
       case MMX6_0: return myfpregs.st_space[12];
       case MMX6_1: return myfpregs.st_space[13];
       case MMX7_0: return myfpregs.st_space[14];
       case MMX7_1: return myfpregs.st_space[15];
       //XMM
       case XMM0_0: return myfpregs.xmm_space[0];
       case XMM0_1: return myfpregs.xmm_space[1];
       case XMM0_2: return myfpregs.xmm_space[2];
       case XMM0_3: return myfpregs.xmm_space[3];
       case XMM1_0: return myfpregs.xmm_space[4];
       case XMM1_1: return myfpregs.xmm_space[5];
       case XMM1_2: return myfpregs.xmm_space[6];
       case XMM1_3: return myfpregs.xmm_space[7];
       case XMM2_0: return myfpregs.xmm_space[8];
       case XMM2_1: return myfpregs.xmm_space[9];
       case XMM2_2: return myfpregs.xmm_space[10];
       case XMM2_3: return myfpregs.xmm_space[11];
       case XMM3_0: return myfpregs.xmm_space[12];
       case XMM3_1: return myfpregs.xmm_space[13];
       case XMM3_2: return myfpregs.xmm_space[14];
       case XMM3_3: return myfpregs.xmm_space[15];
       case XMM4_0: return myfpregs.xmm_space[16];
       case XMM4_1: return myfpregs.xmm_space[17];
       case XMM4_2: return myfpregs.xmm_space[18];
       case XMM4_3: return myfpregs.xmm_space[19];
       case XMM5_0: return myfpregs.xmm_space[20];
       case XMM5_1: return myfpregs.xmm_space[21];
       case XMM5_2: return myfpregs.xmm_space[22];
       case XMM5_3: return myfpregs.xmm_space[23];
       case XMM6_0: return myfpregs.xmm_space[24];
       case XMM6_1: return myfpregs.xmm_space[25];
       case XMM6_2: return myfpregs.xmm_space[26];
       case XMM6_3: return myfpregs.xmm_space[27];
       case XMM7_0: return myfpregs.xmm_space[28];
       case XMM7_1: return myfpregs.xmm_space[29];
       case XMM7_2: return myfpregs.xmm_space[30];
       case XMM7_3: return myfpregs.xmm_space[31];
       case XMM8_0: return myfpregs.xmm_space[32];
       case XMM8_1: return myfpregs.xmm_space[33];
       case XMM8_2: return myfpregs.xmm_space[34];
       case XMM8_3: return myfpregs.xmm_space[35];
       case XMM9_0: return myfpregs.xmm_space[36];
       case XMM9_1: return myfpregs.xmm_space[37];
       case XMM9_2: return myfpregs.xmm_space[38];
       case XMM9_3: return myfpregs.xmm_space[39];
       case XMM10_0: return myfpregs.xmm_space[40];
       case XMM10_1: return myfpregs.xmm_space[41];
       case XMM10_2: return myfpregs.xmm_space[42];
       case XMM10_3: return myfpregs.xmm_space[43];
       case XMM11_0: return myfpregs.xmm_space[44];
       case XMM11_1: return myfpregs.xmm_space[45];
       case XMM11_2: return myfpregs.xmm_space[46];
       case XMM11_3: return myfpregs.xmm_space[47];
       case XMM12_0: return myfpregs.xmm_space[48];
       case XMM12_1: return myfpregs.xmm_space[49];
       case XMM12_2: return myfpregs.xmm_space[50];
       case XMM12_3: return myfpregs.xmm_space[51];
       case XMM13_0: return myfpregs.xmm_space[52];
       case XMM13_1: return myfpregs.xmm_space[53];
       case XMM13_2: return myfpregs.xmm_space[54];
       case XMM13_3: return myfpregs.xmm_space[55];
       case XMM14_0: return myfpregs.xmm_space[56];
       case XMM14_1: return myfpregs.xmm_space[57];
       case XMM14_2: return myfpregs.xmm_space[58];
       case XMM14_3: return myfpregs.xmm_space[59];
       case XMM15_0: return myfpregs.xmm_space[60];
       case XMM15_1: return myfpregs.xmm_space[61];
       case XMM15_2: return myfpregs.xmm_space[62];
       case XMM15_3: return myfpregs.xmm_space[63];
       default:
         assert(0);
         return 0;
     }
 }

 bool
 AMD64TraceChild::update(int pid)
 {
     oldregs = regs;
     oldfpregs = fpregs;
     if (ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0) {
         cerr << "update: " << strerror(errno) << endl;
         return false;
     }
     if (ptrace(PTRACE_GETFPREGS, pid, 0, &fpregs) != 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, fpregs, num);
 }

 int64_t
 AMD64TraceChild::getOldRegVal(int num)
 {
     return getRegs(oldregs, oldfpregs, num);
 }

 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%016lx\n", sp);
     os << obuf;
     sprintf(obuf, "Initial program counter = 0x%016lx\n", pc);
     os << obuf;

     //Output the argument count
     uint64_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
     sprintf(obuf, "0x%016lx: Argc = 0x%016lx\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%016lx: argv[%d] = 0x%016lx\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%016lx: envp[%d] = 0x%016lx\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%016lx: Auxiliary vector = {0x%016lx, 0x%016lx}\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%016lx: \"%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;
 }
	/*
	* 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 <sys/ptrace.h>
	#include <stdint.h>

	#include <cerrno>
	#include <cstring>
	#include <iomanip>
	#include <iostream>

	#include "arch/amd64/tracechild.hh"

	using namespace std;

	bool
	AMD64TraceChild::sendState(int socket)
	{
	uint64_t regVal64 = 0;
	uint32_t regVal32 = 0;
	for (int x = 0; x <= R15; x++) {
	regVal64 = getRegVal(x);
	if (write(socket, &regVal64, sizeof(regVal64)) == -1) {
	cerr << "Write failed! " << strerror(errno) << endl;
	tracing = false;
	return false;
	}
	}
	regVal64 = getRegVal(RIP);
	if (write(socket, &regVal64, sizeof(regVal64)) == -1) {
	cerr << "Write failed! " << strerror(errno) << endl;
	tracing = false;
	return false;
	}
	for (int x = MMX0_0; x <= MMX7_1; x++) {
	regVal32 = getRegVal(x);
	if (write(socket, &regVal32, sizeof(regVal32)) == -1) {
	cerr << "Write failed! " << strerror(errno) << endl;
	tracing = false;
	return false;
	}
	}
	for (int x = XMM0_0; x <= XMM15_3; x++) {
	regVal32 = getRegVal(x);
	if (write(socket, &regVal32, sizeof(regVal32)) == -1) {
	cerr << "Write failed! " << strerror(errno) << endl;
	tracing = false;
	return false;
	}
	}
	return true;
	}

	int64_t
	AMD64TraceChild::getRegs(user_regs_struct & myregs,
	user_fpregs_struct & myfpregs, 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;
	//MMX
	case MMX0_0: return myfpregs.st_space[0];
	case MMX0_1: return myfpregs.st_space[1];
	case MMX1_0: return myfpregs.st_space[2];
	case MMX1_1: return myfpregs.st_space[3];
	case MMX2_0: return myfpregs.st_space[4];
	case MMX2_1: return myfpregs.st_space[5];
	case MMX3_0: return myfpregs.st_space[6];
	case MMX3_1: return myfpregs.st_space[7];
	case MMX4_0: return myfpregs.st_space[8];
	case MMX4_1: return myfpregs.st_space[9];
	case MMX5_0: return myfpregs.st_space[10];
	case MMX5_1: return myfpregs.st_space[11];
	case MMX6_0: return myfpregs.st_space[12];
	case MMX6_1: return myfpregs.st_space[13];
	case MMX7_0: return myfpregs.st_space[14];
	case MMX7_1: return myfpregs.st_space[15];
	//XMM
	case XMM0_0: return myfpregs.xmm_space[0];
	case XMM0_1: return myfpregs.xmm_space[1];
	case XMM0_2: return myfpregs.xmm_space[2];
	case XMM0_3: return myfpregs.xmm_space[3];
	case XMM1_0: return myfpregs.xmm_space[4];
	case XMM1_1: return myfpregs.xmm_space[5];
	case XMM1_2: return myfpregs.xmm_space[6];
	case XMM1_3: return myfpregs.xmm_space[7];
	case XMM2_0: return myfpregs.xmm_space[8];
	case XMM2_1: return myfpregs.xmm_space[9];
	case XMM2_2: return myfpregs.xmm_space[10];
	case XMM2_3: return myfpregs.xmm_space[11];
	case XMM3_0: return myfpregs.xmm_space[12];
	case XMM3_1: return myfpregs.xmm_space[13];
	case XMM3_2: return myfpregs.xmm_space[14];
	case XMM3_3: return myfpregs.xmm_space[15];
	case XMM4_0: return myfpregs.xmm_space[16];
	case XMM4_1: return myfpregs.xmm_space[17];
	case XMM4_2: return myfpregs.xmm_space[18];
	case XMM4_3: return myfpregs.xmm_space[19];
	case XMM5_0: return myfpregs.xmm_space[20];
	case XMM5_1: return myfpregs.xmm_space[21];
	case XMM5_2: return myfpregs.xmm_space[22];
	case XMM5_3: return myfpregs.xmm_space[23];
	case XMM6_0: return myfpregs.xmm_space[24];
	case XMM6_1: return myfpregs.xmm_space[25];
	case XMM6_2: return myfpregs.xmm_space[26];
	case XMM6_3: return myfpregs.xmm_space[27];
	case XMM7_0: return myfpregs.xmm_space[28];
	case XMM7_1: return myfpregs.xmm_space[29];
	case XMM7_2: return myfpregs.xmm_space[30];
	case XMM7_3: return myfpregs.xmm_space[31];
	case XMM8_0: return myfpregs.xmm_space[32];
	case XMM8_1: return myfpregs.xmm_space[33];
	case XMM8_2: return myfpregs.xmm_space[34];
	case XMM8_3: return myfpregs.xmm_space[35];
	case XMM9_0: return myfpregs.xmm_space[36];
	case XMM9_1: return myfpregs.xmm_space[37];
	case XMM9_2: return myfpregs.xmm_space[38];
	case XMM9_3: return myfpregs.xmm_space[39];
	case XMM10_0: return myfpregs.xmm_space[40];
	case XMM10_1: return myfpregs.xmm_space[41];
	case XMM10_2: return myfpregs.xmm_space[42];
	case XMM10_3: return myfpregs.xmm_space[43];
	case XMM11_0: return myfpregs.xmm_space[44];
	case XMM11_1: return myfpregs.xmm_space[45];
	case XMM11_2: return myfpregs.xmm_space[46];
	case XMM11_3: return myfpregs.xmm_space[47];
	case XMM12_0: return myfpregs.xmm_space[48];
	case XMM12_1: return myfpregs.xmm_space[49];
	case XMM12_2: return myfpregs.xmm_space[50];
	case XMM12_3: return myfpregs.xmm_space[51];
	case XMM13_0: return myfpregs.xmm_space[52];
	case XMM13_1: return myfpregs.xmm_space[53];
	case XMM13_2: return myfpregs.xmm_space[54];
	case XMM13_3: return myfpregs.xmm_space[55];
	case XMM14_0: return myfpregs.xmm_space[56];
	case XMM14_1: return myfpregs.xmm_space[57];
	case XMM14_2: return myfpregs.xmm_space[58];
	case XMM14_3: return myfpregs.xmm_space[59];
	case XMM15_0: return myfpregs.xmm_space[60];
	case XMM15_1: return myfpregs.xmm_space[61];
	case XMM15_2: return myfpregs.xmm_space[62];
	case XMM15_3: return myfpregs.xmm_space[63];
	default:
	assert(0);
	return 0;
	}
	}

	bool
	AMD64TraceChild::update(int pid)
	{
	oldregs = regs;
	oldfpregs = fpregs;
	if (ptrace(PTRACE_GETREGS, pid, 0, &regs) != 0) {
	cerr << "update: " << strerror(errno) << endl;
	return false;
	}
	if (ptrace(PTRACE_GETFPREGS, pid, 0, &fpregs) != 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, fpregs, num);
	}

	int64_t
	AMD64TraceChild::getOldRegVal(int num)
	{
	return getRegs(oldregs, oldfpregs, num);
	}

	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%016lx\n", sp);
	os << obuf;
	sprintf(obuf, "Initial program counter = 0x%016lx\n", pc);
	os << obuf;

	//Output the argument count
	uint64_t cargc = ptrace(PTRACE_PEEKDATA, pid, sp, 0);
	sprintf(obuf, "0x%016lx: Argc = 0x%016lx\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%016lx: argv[%d] = 0x%016lx\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%016lx: envp[%d] = 0x%016lx\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%016lx: Auxiliary vector = {0x%016lx, 0x%016lx}\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%016lx: \"%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;
	}