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UefiCpuPkg/RegisterCpuFeaturesLib: Separate semaphore container. 

In current implementation, core and package level sync uses same semaphores.
Sharing the semaphore may cause wrong execution order.
For example:
1. Feature A has CPU_FEATURE_CORE_BEFORE dependency with Feature B.
2. Feature C has CPU_FEATURE_PACKAGE_AFTER dependency with Feature B.
The expected feature initialization order is A B C:
A ---- (Core Depends) ----> B ---- (Package Depends) ----> C

For a CPU has 1 package, 2 cores and 4 threads. The feature initialization
order may like below:

   Thread#1             Thread#2       Thread#3         Thread#4
   [A.Init]             [A.Init]                        [A.Init]
Release(S1, S2)        Release(S1, S2)                Release(S3, S4)
Wait(S1) * 2           Wait(S2) * 2  <------------------------------- Core sync

   [B.Init]             [B.Init]
Release (S1,S2,S3,S4)
Wait (S1) * 4  <----------------------------------------------------- Package sync
                                                      Wait(S4 * 2) <- Core sync
                                                        [B.Init]

In above case, for thread#4, when it syncs in core level, Wait(S4) * 2 isn't
blocked and [B.Init] runs. But [A.Init] hasn't run in thread#3. It's wrong!
Thread#4 should execute [B.Init] after thread#3 executes [A.Init] because B
core level depends on A.

The reason of the wrong execution order is that S4 is released in thread#1
by calling Release (S1, S2, S3, S4) and in thread #4 by calling
Release (S3, S4).

To fix this issue, core level sync and package level sync should use separate
semaphores.

In above example, the S4 released in Release (S1, S2, S3, S4) should not be the
same semaphore as that in Release (S3, S4).

Related BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1311

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Eric Dong 2018-11-08 09:06:33 +08:00
parent c1528b855c
commit 91ff5bba02
2 changed files with 10 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
View File

@ -269,8 +269,10 @@ CpuInitDataInitialize (
DEBUG ((DEBUG_INFO, "Package: %d, Valid Core : %d\n", Index, ValidCoreCountPerPackage[Index]));
}
CpuFeaturesData->CpuFlags.SemaphoreCount = AllocateZeroPool (sizeof (UINT32) * CpuStatus->PackageCount * CpuStatus->MaxCoreCount * CpuStatus->MaxThreadCount);
ASSERT (CpuFeaturesData->CpuFlags.SemaphoreCount != NULL);
CpuFeaturesData->CpuFlags.CoreSemaphoreCount = AllocateZeroPool (sizeof (UINT32) * CpuStatus->PackageCount * CpuStatus->MaxCoreCount * CpuStatus->MaxThreadCount);
ASSERT (CpuFeaturesData->CpuFlags.CoreSemaphoreCount != NULL);
CpuFeaturesData->CpuFlags.PackageSemaphoreCount = AllocateZeroPool (sizeof (UINT32) * CpuStatus->PackageCount * CpuStatus->MaxCoreCount * CpuStatus->MaxThreadCount);
ASSERT (CpuFeaturesData->CpuFlags.PackageSemaphoreCount != NULL);
//
// Get support and configuration PCDs
@ -963,9 +965,9 @@ ProgramProcessorRegister (
// V(0...n) V(0...n) ... V(0...n)
// n * P(0) n * P(1) ... n * P(n)
//
SemaphorePtr = CpuFlags->SemaphoreCount;
switch (RegisterTableEntry->Value) {
case CoreDepType:
SemaphorePtr = CpuFlags->CoreSemaphoreCount;
//
// Get Offset info for the first thread in the core which current thread belongs to.
//
@ -986,6 +988,7 @@ ProgramProcessorRegister (
break;
case PackageDepType:
SemaphorePtr = CpuFlags->PackageSemaphoreCount;
ValidCoreCountPerPackage = (UINT32 *)(UINTN)CpuStatus->ValidCoreCountPerPackage;
//
// Get Offset info for the first thread in the package which current thread belongs to.

3
UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeatures.h
View File

@ -62,7 +62,8 @@ typedef struct {
typedef struct {
volatile UINTN ConsoleLogLock; // Spinlock used to control console.
volatile UINTN MemoryMappedLock; // Spinlock used to program mmio
volatile UINT32 *SemaphoreCount; // Semaphore used to program semaphore.
volatile UINT32 *CoreSemaphoreCount; // Semaphore containers used to program Core semaphore.
volatile UINT32 *PackageSemaphoreCount; // Semaphore containers used to program Package semaphore.
} PROGRAM_CPU_REGISTER_FLAGS;
typedef struct {