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sim: don't ignore SIG_TRAP

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By ignoring SIG_TRAP, using --debug-break <N> when not connected to
a debugger becomes a no-op.  Apparently this was intended to be a
feature, though the rationale is not clear.

If we don't ignore SIG_TRAP, then using --debug-break <N> when not
connected to a debugger causes the simulation process to terminate
at tick N.  This is occasionally useful, e.g., if you just want to
collect a trace for a specific window of execution then you can combine
this with --debug-start to do exactly that.

In addition to not ignoring the signal, this patch also updates
the --debug-break help message and deletes a handful of unprotected
calls to Debug::breakpoint() that relied on the prior behavior.
This commit is contained in:
Steve Reinhardt 2016-01-17 18:27:46 -08:00
parent fcfe6e798d
commit 28a0e5a165
5 changed files with 5 additions and 16 deletions
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5
src/arch/alpha/ev5.cc
View file

@ -271,11 +271,6 @@ ISA::setIpr(int idx, uint64_t val, ThreadContext *tc)
break;
case IPR_IPLR:
#ifdef DEBUG
if (break_ipl != -1 && break_ipl == (int)(val & 0x1f))
Debug::breakpoint();
#endif
// only write least significant five bits - interrupt level
ipr[idx] = val & 0x1f;
if (tc->getKernelStats())

3
src/dev/net/ns_gige.cc
View file

@ -951,7 +951,6 @@ NSGigE::cpuIntrPost(Tick when)
intrTick = when;
if (intrTick < curTick()) {
Debug::breakpoint();
intrTick = curTick();
}
@ -1725,7 +1724,6 @@ NSGigE::txKick()
tcp->sum(cksum(tcp));
txTcpChecksums++;
} else {
Debug::breakpoint();
warn_once("TCPPKT set, but not UDP!\n");
}
}
@ -1735,7 +1733,6 @@ NSGigE::txKick()
ip->sum(cksum(ip));
txIpChecksums++;
} else {
Debug::breakpoint();
warn_once("IPPKT set, but not UDP!\n");
}
}

1
src/dev/net/sinic.cc
View file

@ -527,7 +527,6 @@ Base::cpuIntrPost(Tick when)
intrTick = when;
if (intrTick < curTick()) {
Debug::breakpoint();
intrTick = curTick();
}

9
src/python/m5/main.py
View file

@ -94,14 +94,15 @@ def parse_options():
# Debugging options
group("Debugging Options")
option("--debug-break", metavar="TIME[,TIME]", action='append', split=',',
help="Tick to create a breakpoint")
option("--debug-break", metavar="TICK[,TICK]", action='append', split=',',
help="Create breakpoint(s) at TICK(s) " \
"(kills process if no debugger attached)")
option("--debug-help", action='store_true',
help="Print help on debug flags")
option("--debug-flags", metavar="FLAG[,FLAG]", action='append', split=',',
help="Sets the flags for debug output (-FLAG disables a flag)")
option("--debug-start", metavar="TIME", type='int',
help="Start debug output at TIME (must be in ticks)")
option("--debug-start", metavar="TICK", type='int',
help="Start debug output at TICK (must be in ticks)")
option("--debug-file", metavar="FILE", default="cout",
help="Sets the output file for debug [Default: %default]")
option("--debug-ignore", metavar="EXPR", action='append', split=':',

3
src/sim/init_signals.cc
View file

@ -178,9 +178,6 @@ initSignals()
// ignore them
signal(SIGFPE, SIG_IGN);
// We use SIGTRAP sometimes for debugging
signal(SIGTRAP, SIG_IGN);
// Dump intermediate stats
installSignalHandler(SIGUSR1, dumpStatsHandler);