UefiCpuPkg/PiSmmCpuDxeSmm: Decrease mNumberToFinish in AP safe code
We will put APs into hlt-loop in safe code. But we decrease mNumberToFinish
before APs enter into the safe code. Paolo pointed out this gap.
This patch is to move mNumberToFinish decreasing to the safe code. It could
make sure BSP could wait for all APs are running in safe code.
https://bugzilla.tianocore.org/show_bug.cgi?id=216
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
index ad7dc41..3fb6864 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
@@ -79,9 +79,11 @@
UINT8 *mApHltLoopCode = NULL;
UINT8 mApHltLoopCodeTemplate[] = {
- 0xFA, // cli
- 0xF4, // hlt
- 0xEB, 0xFC // jmp $-2
+ 0x8B, 0x44, 0x24, 0x04, // mov eax, dword ptr [esp+4]
+ 0xF0, 0xFF, 0x08, // lock dec dword ptr [eax]
+ 0xFA, // cli
+ 0xF4, // hlt
+ 0xEB, 0xFC // jmp $-2
};
/**
@@ -399,17 +401,12 @@
}
//
- // Count down the number with lock mechanism.
- //
- InterlockedDecrement (&mNumberToFinish);
-
- //
- // Place AP into the safe code
+ // Place AP into the safe code, count down the number with lock mechanism in the safe code.
//
TopOfStack = (UINT32) (UINTN) Stack + sizeof (Stack);
TopOfStack &= ~(UINT32) (CPU_STACK_ALIGNMENT - 1);
CopyMem ((VOID *) (UINTN) mApHltLoopCode, mApHltLoopCodeTemplate, sizeof (mApHltLoopCodeTemplate));
- TransferApToSafeState ((UINT32) (UINTN) mApHltLoopCode, TopOfStack);
+ TransferApToSafeState ((UINT32) (UINTN) mApHltLoopCode, TopOfStack, &mNumberToFinish);
}
/**
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmFuncsArch.c b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmFuncsArch.c
index 8b880d6..9760373 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmFuncsArch.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmFuncsArch.c
@@ -100,17 +100,19 @@
@param[in] ApHltLoopCode The 32-bit address of the safe hlt-loop function.
@param[in] TopOfStack A pointer to the new stack to use for the ApHltLoopCode.
+ @param[in] NumberToFinish Semaphore of APs finish count.
**/
VOID
TransferApToSafeState (
IN UINT32 ApHltLoopCode,
- IN UINT32 TopOfStack
+ IN UINT32 TopOfStack,
+ IN UINT32 *NumberToFinish
)
{
SwitchStack (
(SWITCH_STACK_ENTRY_POINT) (UINTN) ApHltLoopCode,
- NULL,
+ NumberToFinish,
NULL,
(VOID *) (UINTN) TopOfStack
);
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
index 6c98659..88d9c85 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h
@@ -830,12 +830,14 @@
@param[in] ApHltLoopCode The 32-bit address of the safe hlt-loop function.
@param[in] TopOfStack A pointer to the new stack to use for the ApHltLoopCode.
+ @param[in] NumberToFinish Semaphore of APs finish count.
**/
VOID
TransferApToSafeState (
IN UINT32 ApHltLoopCode,
- IN UINT32 TopOfStack
+ IN UINT32 TopOfStack,
+ IN UINT32 *NumberToFinish
);
#endif
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
index 62338b7..6844c3f 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c
@@ -105,18 +105,20 @@
@param[in] ApHltLoopCode The 32-bit address of the safe hlt-loop function.
@param[in] TopOfStack A pointer to the new stack to use for the ApHltLoopCode.
+ @param[in] NumberToFinish Semaphore of APs finish count.
**/
VOID
TransferApToSafeState (
IN UINT32 ApHltLoopCode,
- IN UINT32 TopOfStack
+ IN UINT32 TopOfStack,
+ IN UINT32 *NumberToFinish
)
{
AsmDisablePaging64 (
GetProtectedModeCS (),
(UINT32) (UINTN) ApHltLoopCode,
- 0,
+ (UINT32) (UINTN) NumberToFinish,
0,
TopOfStack
);
