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authorGabe Black <gblack@eecs.umich.edu>2006-10-19 14:57:06 -0400
committerGabe Black <gblack@eecs.umich.edu>2006-10-19 14:57:06 -0400
commit76c07ea46bc4f8f6d500f909abfb07addf217940 (patch)
tree1d90888d6ad8ff09f90a031fde09256125681565 /util
parent54c9701a257656cf07d1f2ca93f5c5d558f878f9 (diff)
downloadgem5-76c07ea46bc4f8f6d500f909abfb07addf217940.tar.xz
Cleaned up the function a bit to help route out bugs.
--HG-- extra : convert_revision : db9a526bddc8634cea63b42b882f580806066db5
Diffstat (limited to 'util')
-rw-r--r--util/statetrace/arch/tracechild_sparc.cc102
1 files changed, 83 insertions, 19 deletions
diff --git a/util/statetrace/arch/tracechild_sparc.cc b/util/statetrace/arch/tracechild_sparc.cc
index 1dc62412a..bad81b647 100644
--- a/util/statetrace/arch/tracechild_sparc.cc
+++ b/util/statetrace/arch/tracechild_sparc.cc
@@ -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
+ {
+ //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
{
- if(ptrace(PTRACE_POKETEXT, pid, alignedPC, breakWord) != 0)
+ //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;