thermosphere: gdb/debug: avoid pause/unpause race condition in vCont + bugfix

This commit is contained in:
TuxSH 2020-01-30 01:22:37 +00:00
parent 9ef2532b9d
commit 36ca87491d
6 changed files with 39 additions and 15 deletions

View file

@ -50,7 +50,7 @@ static void debugManagerDoPauseCores(u32 coreList)
do {
desiredList |= readList;
remainingList &= ~readList;
} while (atomic_compare_exchange_weak(&g_debugManager.pausedCoreList, &readList, desiredList));
} while (!atomic_compare_exchange_weak(&g_debugManager.pausedCoreList, &readList, desiredList));
if (remainingList != BIT(currentCoreCtx->coreId)) {
// We need to notify other cores...
@ -116,10 +116,13 @@ void debugManagerPauseCores(u32 coreList)
restoreInterruptFlags(flags);
}
void debugManagerUnpauseCores(u32 coreList, u32 singleStepList)
void debugManagerSetSingleStepCoreList(u32 coreList)
{
singleStepList &= coreList;
atomic_store(&g_debugManager.singleStepCoreList, coreList);
}
void debugManagerUnpauseCores(u32 coreList)
{
FOREACH_BIT (tmp, coreId, coreList) {
if (&g_debugManager.debugEventInfos[coreId].handled) {
// Discard already handled debug events
@ -127,8 +130,6 @@ void debugManagerUnpauseCores(u32 coreList, u32 singleStepList)
}
}
// Since we're using a debugger lock, a simple stlr should be fine...
atomic_store(&g_debugManager.singleStepCoreList, singleStepList);
atomic_fetch_and(&g_debugManager.pausedCoreList, ~coreList);
__sev();
@ -198,7 +199,18 @@ void debugManagerBreakCores(u32 coreList)
if (coreList & ~BIT(coreId)) {
generateSgiForList(ThermosphereSgi_ReportDebuggerBreak, coreList & ~BIT(coreId));
}
if (coreList & BIT(coreId)) {
if (coreList & BIT(coreId) && !debugManagerIsCorePaused(coreId)) {
debugManagerReportEvent(DBGEVENT_DEBUGGER_BREAK);
}
}
void debugManagerContinueCores(u32 coreList)
{
u32 coreId = currentCoreCtx->coreId;
if (coreList & ~BIT(coreId)) {
generateSgiForList(ThermosphereSgi_DebuggerContinue, coreList & ~BIT(coreId));
}
if (coreList & BIT(coreId) && debugManagerIsCorePaused(coreId)) {
debugManagerUnpauseCores(BIT(coreId));
}
}

View file

@ -55,7 +55,8 @@ bool debugManagerHandlePause(void);
// "Pause" makes sure all cores reaches the pause function before proceeding.
// "Unpause" doesn't synchronize, it just makes sure the core resumes & that "pause" can be called again.
void debugManagerPauseCores(u32 coreList);
void debugManagerUnpauseCores(u32 coreList, u32 singleStepList);
void debugManagerUnpauseCores(u32 coreList);
void debugManagerSetSingleStepCoreList(u32 coreList);
void debugManagerSetSteppingRange(u32 coreId, uintptr_t startAddr, uintptr_t endAddr);
@ -67,6 +68,7 @@ const DebugEventInfo *debugManagerGetCoreDebugEvent(u32 coreId);
void debugManagerReportEvent(DebugEventType type, ...);
void debugManagerBreakCores(u32 coreList);
void debugManagerContinueCores(u32 coreList);
static inline bool debugManagerIsCorePaused(u32 coreId)
{

View file

@ -347,7 +347,8 @@ GDB_DECLARE_HANDLER(ContinueOrStepDeprecated)
debugManagerSetSteppingRange(coreId, 0, 0);
}
debugManagerUnpauseCores(coreList, ssMask);
debugManagerSetSingleStepCoreList(ssMask);
debugManagerUnpauseCores(coreList);
return 0;
}
@ -461,8 +462,9 @@ GDB_DECLARE_VERBOSE_HANDLER(Continue)
cmd = nextCmd;
}
debugManagerSetSingleStepCoreList(stepCoreList);
debugManagerBreakCores(stopCoreList);
debugManagerUnpauseCores(continueCoreList, stepCoreList);
debugManagerContinueCores(continueCoreList);
return 0;
}

View file

@ -220,6 +220,7 @@ void handleIrqException(ExceptionStackFrame *frame, bool isLowerEl, bool isA32)
bool isGuestInterrupt = false;
bool isMaintenanceInterrupt = false;
bool isPaused = false;
switch (irqId) {
case ThermosphereSgi_ExecuteFunction:
@ -232,7 +233,11 @@ void handleIrqException(ExceptionStackFrame *frame, bool isLowerEl, bool isA32)
debugManagerPauseSgiHandler();
break;
case ThermosphereSgi_ReportDebuggerBreak:
// See bottom half
case ThermosphereSgi_DebuggerContinue:
// See bottom halves
// Because exceptions (other debug events) are handling w/ interrupts off, if
// we get there, there's no race condition possible with debugManagerReportEvent
isPaused = debugManagerIsCorePaused(currentCoreCtx->coreId);
break;
case GIC_IRQID_MAINTENANCE:
isMaintenanceInterrupt = true;
@ -274,8 +279,10 @@ void handleIrqException(ExceptionStackFrame *frame, bool isLowerEl, bool isA32)
exceptionEnterInterruptibleHypervisorCode();
unmaskIrq();
transportInterfaceIrqHandlerBottomHalf(transportIface);
} else if (irqId == ThermosphereSgi_ReportDebuggerBreak) {
} else if (irqId == ThermosphereSgi_ReportDebuggerBreak && !isPaused) {
debugManagerReportEvent(DBGEVENT_DEBUGGER_BREAK);
} else if (irqId == ThermosphereSgi_DebuggerContinue && isPaused) {
debugManagerUnpauseCores(BIT(currentCoreCtx->coreId));
}
}

View file

@ -39,9 +39,10 @@ typedef struct IrqManager {
typedef enum ThermosphereSgi {
ThermosphereSgi_ExecuteFunction = 0,
ThermosphereSgi_VgicUpdate = 1,
ThermosphereSgi_DebugPause = 2,
ThermosphereSgi_ReportDebuggerBreak = 3,
ThermosphereSgi_VgicUpdate,
ThermosphereSgi_DebugPause,
ThermosphereSgi_ReportDebuggerBreak,
ThermosphereSgi_DebuggerContinue,
ThermosphereSgi_Max,
} ThermosphereSgi;

View file

@ -75,7 +75,7 @@ void testProcessDataCallback(TransportInterface *iface, void *p, size_t sz)
{
(void)iface;
(void)sz;
debugManagerUnpauseCores(BIT(0), BIT(0));
debugManagerUnpauseCores(BIT(0));
TestCtx *ctx = (TestCtx *)p;
DEBUG("EL2 [core %u]: you typed: %s\n", currentCoreCtx->coreId, ctx->buf);
}