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Cleaned up the function a bit to help route out bugs.

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--HG--
extra : convert_revision : db9a526bddc8634cea63b42b882f580806066db5
This commit is contained in:
Gabe Black 2006-10-19 14:57:06 -04:00
parent 54c9701a25
commit 76c07ea46b
1 changed files with 83 additions and 19 deletions
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102
util/statetrace/arch/tracechild_sparc.cc
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@ -188,46 +188,110 @@ bool SparcTraceChild::step()
//being breakpointed should be word (64bit) aligned, and that both the
//next instruction and the instruction after that need to be breakpointed
//so that annulled branches will still stop as well.
/*
* Useful constants
*/
const static uint64_t breakInst = 0x91d02001;
const static uint64_t breakWord = breakInst | (breakInst << 32);
const static uint64_t lowMask = (uint64_t)(0xFFFFFFFF);
const static uint64_t lowMask = 0xFFFFFFFFULL;
const static uint64_t highMask = lowMask << 32;
/*
* storage for the original contents of the child process's memory
*/
uint64_t originalInst, originalAnnulInst;
/*
* Get information about where the process is and is headed next.
*/
uint64_t currentPC = getRegVal(PC);
bool unalignedPC = currentPC & 7;
uint64_t alignedPC = currentPC & (~7);
uint64_t nextPC = getRegVal(NPC);
bool unaligned = nextPC & 7;
uint64_t alignedPC = nextPC & (~7);
originalInst = ptrace(PTRACE_PEEKTEXT, pid, alignedPC, 0);
if(unaligned)
bool unalignedNPC = nextPC & 7;
uint64_t alignedNPC = nextPC & (~7);
/*
* Store the original contents of the child process's memory
*/
originalInst = ptrace(PTRACE_PEEKTEXT, pid, alignedNPC, 0);
//Save a ptrace call if we can
if(unalignedNPC)
{
originalAnnulInst = ptrace(PTRACE_PEEKTEXT, pid, alignedPC+8, 0);
originalAnnulInst = ptrace(PTRACE_PEEKTEXT, pid, alignedNPC+8, 0);
}
uint64_t newInst;
if(unaligned)
/*
* Prepare breakpointed copies of child processes memory
*/
uint64_t newInst, newAnnulInst;
//If the current instruction is in the same word as the npc
if(alignedPC == alignedNPC)
{
newInst = (originalInst & highMask) | (breakInst << 0);
if(ptrace(PTRACE_POKETEXT, pid, alignedPC, newInst) != 0)
cerr << "Poke failed" << endl;
newInst = (originalAnnulInst & lowMask) | (breakInst << 32);
if(ptrace(PTRACE_POKETEXT, pid, alignedPC+8, newInst) != 0)
cerr << "Poke failed" << endl;
//Make sure we only replace the other part
if(unalignedPC)
newInst = (originalInst & lowMask) | (breakWord & highMask);
else
newInst = (originalInst & highMask) | (breakWord & lowMask);
}
else
{
if(ptrace(PTRACE_POKETEXT, pid, alignedPC, breakWord) != 0)
//otherwise replace the whole thing
newInst = breakWord;
}
//If the current instruction is in the same word as the word after
//the npc
if(alignedPC == alignedNPC+8)
{
//Make sure we only replace the other part
if(unalignedPC)
newAnnulInst = (originalAnnulInst & lowMask) | (breakWord & highMask);
else
newAnnulInst = (originalAnnulInst & highMask) | (breakWord & lowMask);
}
else
{
//otherwise replace the whole thing
newAnnulInst = breakWord;
}
/*
* Stuff the breakpoint instructions into the child's address space.
*/
//Replace the word at npc
if(ptrace(PTRACE_POKETEXT, pid, alignedNPC, newInst) != 0)
cerr << "Poke failed" << endl;
//Replace the next word, if necessary
if(unalignedNPC)
{
if(ptrace(PTRACE_POKETEXT, pid, alignedNPC+8, newAnnulInst) != 0)
cerr << "Poke failed" << endl;
}
/*
* Restart the child process
*/
//Note that the "addr" parameter is supposed to be ignored, but in at
//least one version of the kernel, it must be 1 or it will set what
//pc to continue from
if(ptrace(PTRACE_CONT, pid, /*nextPC - 4*/ 1, 0) != 0)
if(ptrace(PTRACE_CONT, pid, 1, 0) != 0)
cerr << "Cont failed" << endl;
doWait();
/*
* Update our record of the child's state
*/
update(pid);
if(ptrace(PTRACE_POKETEXT, pid, alignedPC, originalInst) != 0)
/*
* Put back the original contents of the childs address space
*/
if(ptrace(PTRACE_POKETEXT, pid, alignedNPC, originalInst) != 0)
cerr << "Repoke failed" << endl;
if(unaligned)
if(unalignedNPC)
{
if(ptrace(PTRACE_POKETEXT, pid, alignedPC+8, originalAnnulInst) != 0)
if(ptrace(PTRACE_POKETEXT, pid, alignedNPC+8, originalAnnulInst) != 0)
cerr << "Repoke failed" << endl;
}
return true;