Changeset 75704 in vbox

Timestamp:

Nov 25, 2018 1:44:09 AM (6 years ago)

Author:

vboxsync

Message:

IPRT/r0drv/darwin: RTSemEventSignal and RTSemEventMultiSignal seems to work fine with interrupts disabled and/or from interrupt context. bugref:4686

Location:

trunk

Files:

• include/iprt/semaphore.h (modified) (2 diffs)
• src/VBox/Runtime/r0drv/darwin/semevent-r0drv-darwin.cpp (modified) (2 diffs)
• src/VBox/Runtime/r0drv/darwin/semeventmulti-r0drv-darwin.cpp (modified) (2 diffs)

trunk/include/iprt/semaphore.h

@@ -164 +164 @@
  *          system specific whether it works in interrupt context or with
  *          interrupts disabled.
+ *
+ *          ring-0/Darwin: This works when interrupts are disabled and thereby
+ *          in interrupt context, except it cannot race semaphore destruction as
+ *          the allocator does not work under these circumstances.
  */
 RTDECL(int)  RTSemEventSignal(RTSEMEVENT hEventSem);
@@ -325 +329 @@
  *          system specific whether it works in interrupt context or with
  *          interrupts disabled.
+ *
+ *          ring-0/Darwin: This works when interrupts are disabled and thereby
+ *          in interrupt context, except it cannot race semaphore destruction as
+ *          the allocator does not work under these circumstances.
  */
 RTDECL(int)  RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem);

trunk/src/VBox/Runtime/r0drv/darwin/semevent-r0drv-darwin.cpp

@@ -199 +199 @@
                     VERR_INVALID_HANDLE);
     RT_ASSERT_PREEMPT_CPUID_VAR();
-    RT_ASSERT_INTS_ON();
+
+    /*
+     * Coming here with interrupts disabled should be okay.  The thread_wakeup_prim KPI is used
+     * by the interrupt handler IOFilterInterruptEventSource::disableInterruptOccurred() via
+     * signalWorkAvailable().  The only problem is if we have to destroy the event structure,
+     * as RTMemFree does not work with interrupts disabled (IOFree/kfree takes zone mutex).
+     */
+    //RT_ASSERT_INTS_ON(); - we may be called from interrupt context, which seems to be perfectly fine.
     IPRT_DARWIN_SAVE_EFL_AC();
 
@@ -229 +236 @@
 
     RT_ASSERT_PREEMPT_CPUID();
+    AssertMsg((fSavedEfl & X86_EFL_IF) == (ASMGetFlags() & X86_EFL_IF), ("fSavedEfl=%#x cur=%#x\n",(uint32_t)fSavedEfl, ASMGetFlags()));
     IPRT_DARWIN_RESTORE_EFL_AC();
     return VINF_SUCCESS;

trunk/src/VBox/Runtime/r0drv/darwin/semeventmulti-r0drv-darwin.cpp

@@ -199 +199 @@
     AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("pThis=%p u32Magic=%#x\n", pThis, pThis->u32Magic), VERR_INVALID_HANDLE);
     RT_ASSERT_PREEMPT_CPUID_VAR();
-    RT_ASSERT_INTS_ON();
+
+    /*
+     * Coming here with interrupts disabled should be okay.  The thread_wakeup_prim KPI is used
+     * by the interrupt handler IOFilterInterruptEventSource::disableInterruptOccurred() via
+     * signalWorkAvailable().  The only problem is if we have to destroy the event structure,
+     * as RTMemFree does not work with interrupts disabled (IOFree/kfree takes zone mutex).
+     */
+    //RT_ASSERT_INTS_ON(); - we may be called from interrupt context, which seems to be perfectly fine.
+
     IPRT_DARWIN_SAVE_EFL_AC();
 
@@ -226 +234 @@
 
     RT_ASSERT_PREEMPT_CPUID();
+    AssertMsg((fSavedEfl & X86_EFL_IF) == (ASMGetFlags() & X86_EFL_IF), ("fSavedEfl=%#x cur=%#x\n",(uint32_t)fSavedEfl, ASMGetFlags()));
     IPRT_DARWIN_RESTORE_EFL_AC();
     return VINF_SUCCESS;