Re: [Patch] UefiCpuPkg/MpInitLib: Avoid call PcdGe* in Ap & Bsp.

[Laszlo Ersek <lersek@redhat.com>]

On 10/19/17 04:42, Eric Dong wrote:
> MicrocodeDetect function will run by every threads, and it will
> use PcdGet to get PcdCpuMicrocodePatchAddress and
> PcdCpuMicrocodePatchRegionSize, if change both PCD default to dynamic,
> system will in non-deterministic behavior.
> 
> By design, UEFI/PI services are single threaded and not re-entrant
> so Multi processor code should not use UEFI/PI services. Here, Pcd
> protocol/PPI is used to access dynamic PCDs so it would result in
> non-deterministic behavior.
> 
> This code get PCD value in BSP and save them in CPU_MP_DATA for Ap.
> 
> https://bugzilla.tianocore.org/show_bug.cgi?id=726
> 
> Cc: Crystal Lee <CrystalLee@ami.com.tw>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>  UefiCpuPkg/Library/MpInitLib/Microcode.c | 10 +++-------
>  UefiCpuPkg/Library/MpInitLib/MpLib.c     |  2 ++
>  UefiCpuPkg/Library/MpInitLib/MpLib.h     |  2 ++
>  3 files changed, 7 insertions(+), 7 deletions(-)

Eric, can you please fix up the subject line after you get an R-b and
are about to push the patch?

-UefiCpuPkg/MpInitLib: Avoid call PcdGe* in Ap & Bsp.
+UefiCpuPkg/MpInitLib: Avoid call PcdGet* in Ap & Bsp.

Thanks!
Laszlo


> diff --git a/UefiCpuPkg/Library/MpInitLib/Microcode.c b/UefiCpuPkg/Library/MpInitLib/Microcode.c
> index 982995b..35f66f7 100644
> --- a/UefiCpuPkg/Library/MpInitLib/Microcode.c
> +++ b/UefiCpuPkg/Library/MpInitLib/Microcode.c
> @@ -42,8 +42,6 @@ MicrocodeDetect (
>    IN CPU_MP_DATA             *CpuMpData
>    )
>  {
> -  UINT64                                  MicrocodePatchAddress;
> -  UINT64                                  MicrocodePatchRegionSize;
>    UINT32                                  ExtendedTableLength;
>    UINT32                                  ExtendedTableCount;
>    CPU_MICROCODE_EXTENDED_TABLE            *ExtendedTable;
> @@ -61,9 +59,7 @@ MicrocodeDetect (
>    VOID                                    *MicrocodeData;
>    MSR_IA32_PLATFORM_ID_REGISTER           PlatformIdMsr;
>  
> -  MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);
> -  MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);
> -  if (MicrocodePatchRegionSize == 0) {
> +  if (CpuMpData->MicrocodePatchRegionSize == 0) {
>      //
>      // There is no microcode patches
>      //
> @@ -93,8 +89,8 @@ MicrocodeDetect (
>  
>    LatestRevision = 0;
>    MicrocodeData  = NULL;
> -  MicrocodeEnd = (UINTN) (MicrocodePatchAddress + MicrocodePatchRegionSize);
> -  MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN) MicrocodePatchAddress;
> +  MicrocodeEnd = (UINTN) (CpuMpData->MicrocodePatchAddress + CpuMpData->MicrocodePatchRegionSize);
> +  MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN) CpuMpData->MicrocodePatchAddress;
>    do {
>      //
>      // Check if the microcode is for the Cpu and the version is newer
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> index 924b909..f3ee6d4 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> @@ -1458,6 +1458,8 @@ MpInitLibInitialize (
>    CpuMpData->SwitchBspFlag    = FALSE;
>    CpuMpData->CpuData          = (CPU_AP_DATA *) (CpuMpData + 1);
>    CpuMpData->CpuInfoInHob     = (UINT64) (UINTN) (CpuMpData->CpuData + MaxLogicalProcessorNumber);
> +  CpuMpData->MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);
> +  CpuMpData->MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);
>    InitializeSpinLock(&CpuMpData->MpLock);
>    //
>    // Save BSP's Control registers to APs
> diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
> index 19defda..84ae24f 100644
> --- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
> +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
> @@ -233,6 +233,8 @@ struct _CPU_MP_DATA {
>    UINT8                          Vector;
>    BOOLEAN                        PeriodicMode;
>    BOOLEAN                        TimerInterruptState;
> +  UINT64                         MicrocodePatchAddress;
> +  UINT64                         MicrocodePatchRegionSize;
>  };
>  
>  extern EFI_GUID mCpuInitMpLibHobGuid;
>