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syscall emulation: fix DPRINTF arg ordering bug

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When we switched getSyscallArg() from explicit arg indices to
the implicit method, some DPRINTF arguments were left as calls
to getSyscallArg(), even though C/C++ doesn't guarantee
anything about the order of invocation of these calls.  As a
result, the args could be printed out in arbitrary orders.

Interestingly, this bug has been around since 2009:
http://repo.gem5.org/gem5/rev/4842482e1bd1
This commit is contained in:
Steve Reinhardt 2014-07-18 22:05:51 -07:00
parent 59c8c454eb
commit f5aace8300
1 changed files with 17 additions and 14 deletions
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27
src/sim/syscall_emul.cc
View file

@ -55,16 +55,19 @@ using namespace TheISA;
void
SyscallDesc::doSyscall(int callnum, LiveProcess *process, ThreadContext *tc)
{
#if TRACING_ON
if (DTRACE(SyscallVerbose)) {
int index = 0;
#endif
DPRINTFR(SyscallVerbose,
"%d: %s: syscall %s called w/arguments %d,%d,%d,%d\n",
IntReg arg[4];
// we can't just put the calls to getSyscallArg() in the
// DPRINTF arg list, because C++ doesn't guarantee their order
for (int i = 0; i < 4; ++i)
arg[i] = process->getSyscallArg(tc, index);
DPRINTFNR("%d: %s: syscall %s called w/arguments %d,%d,%d,%d\n",
curTick(), tc->getCpuPtr()->name(), name,
process->getSyscallArg(tc, index),
process->getSyscallArg(tc, index),
process->getSyscallArg(tc, index),
process->getSyscallArg(tc, index));
arg[0], arg[1], arg[2], arg[3]);
}
SyscallReturn retval = (*funcPtr)(this, callnum, process, tc);
@ -91,8 +94,8 @@ ignoreFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
ThreadContext *tc)
{
int index = 0;
warn("ignoring syscall %s(%d, %d, ...)", desc->name,
process->getSyscallArg(tc, index), process->getSyscallArg(tc, index));
warn("ignoring syscall %s(%d, ...)", desc->name,
process->getSyscallArg(tc, index));
return 0;
}
@ -103,8 +106,8 @@ ignoreWarnOnceFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
ThreadContext *tc)
{
int index = 0;
warn_once("ignoring syscall %s(%d, %d, ...)", desc->name,
process->getSyscallArg(tc, index), process->getSyscallArg(tc, index));
warn_once("ignoring syscall %s(%d, ...)", desc->name,
process->getSyscallArg(tc, index));
return 0;
}