Re: [Patch 3/3] UefiCpuPkg/RegisterCpuFeaturesLib: Simplify PcdCpuFeaturesSupport.

[Laszlo Ersek <lersek@redhat.com>]

On 02/13/19 03:04, Eric Dong wrote:
> PcdCpuFeaturesSupport used to specify the platform policy about
> what CPU features this platform supports. This value is decide by
> platform owner, not by hardware. After this change, this PCD will
> be used in IsCpuFeatureSupported function only.
> 
> Now RegisterCpuFeaturesLib use this PCD as an template to Get the
> pcd size. Update the code logic to replace it with
> PcdCpuFeaturesSetting.
> 
> BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=1375
> 
> Cc: Ray Ni <Ray.ni@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>  .../RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 66 +++++++---------------
>  .../RegisterCpuFeaturesLib/RegisterCpuFeatures.h   |  1 -
>  .../RegisterCpuFeaturesLib.c                       | 10 ++--
>  3 files changed, 24 insertions(+), 53 deletions(-)
> 
> diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> index 4ebd0025b4..762eaec277 100644
> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> @@ -74,27 +74,6 @@ GetSettingPcd (
>    return SettingBitMask;
>  }
>  
> -/**
> -  Worker function to get PcdCpuFeaturesSupport.
> -
> -  @return  The pointer to CPU feature bits mask buffer.
> -**/
> -UINT8 *
> -GetSupportPcd (
> -  VOID
> -  )
> -{
> -  UINT8                  *SupportBitMask;
> -
> -  SupportBitMask = AllocateCopyPool (
> -          PcdGetSize (PcdCpuFeaturesSupport),
> -          PcdGetPtr (PcdCpuFeaturesSupport)
> -          );
> -  ASSERT (SupportBitMask != NULL);
> -
> -  return SupportBitMask;
> -}
> -
>  /**
>    Collects CPU type and feature information.
>  
> @@ -282,11 +261,6 @@ CpuInitDataInitialize (
>    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
> -  //
> -  CpuFeaturesData->SupportPcd       = GetSupportPcd ();
>  }
>  
>  /**
> @@ -306,7 +280,7 @@ SupportedMaskOr (
>    UINT8                  *Data1;
>    UINT8                  *Data2;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>    Data1 = SupportedFeatureMask;
>    Data2 = OrFeatureBitMask;
>    for (Index = 0; Index < BitMaskSize; Index++) {
> @@ -331,7 +305,7 @@ SupportedMaskAnd (
>    UINT8                  *Data1;
>    UINT8                  *Data2;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>    Data1 = SupportedFeatureMask;
>    Data2 = AndFeatureBitMask;
>    for (Index = 0; Index < BitMaskSize; Index++) {
> @@ -356,7 +330,7 @@ SupportedMaskCleanBit (
>    UINT8                  *Data1;
>    UINT8                  *Data2;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>    Data1 = SupportedFeatureMask;
>    Data2 = AndFeatureBitMask;
>    for (Index = 0; Index < BitMaskSize; Index++) {
> @@ -387,7 +361,7 @@ IsBitMaskMatch (
>    UINT8                  *Data1;
>    UINT8                  *Data2;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>  
>    Data1 = SupportedFeatureMask;
>    Data2 = ComparedFeatureBitMask;
> @@ -426,22 +400,22 @@ CollectProcessorData (
>    Entry = GetFirstNode (&CpuFeaturesData->FeatureList);
>    while (!IsNull (&CpuFeaturesData->FeatureList, Entry)) {
>      CpuFeature = CPU_FEATURE_ENTRY_FROM_LINK (Entry);
> -    if (IsBitMaskMatch (CpuFeaturesData->SupportPcd, CpuFeature->FeatureMask)) {
> -      if (CpuFeature->SupportFunc == NULL) {
> -        //
> -        // If SupportFunc is NULL, then the feature is supported.
> -        //
> -        SupportedMaskOr (
> -          CpuFeaturesData->InitOrder[ProcessorNumber].FeaturesSupportedMask,
> -          CpuFeature->FeatureMask
> -          );
> -      } else if (CpuFeature->SupportFunc (ProcessorNumber, CpuInfo, CpuFeature->ConfigData)) {
> -        SupportedMaskOr (
> -          CpuFeaturesData->InitOrder[ProcessorNumber].FeaturesSupportedMask,
> -          CpuFeature->FeatureMask
> -          );
> -      }
> +
> +    if (CpuFeature->SupportFunc == NULL) {
> +      //
> +      // If SupportFunc is NULL, then the feature is supported.
> +      //
> +      SupportedMaskOr (
> +        CpuFeaturesData->InitOrder[ProcessorNumber].FeaturesSupportedMask,
> +        CpuFeature->FeatureMask
> +        );
> +    } else if (CpuFeature->SupportFunc (ProcessorNumber, CpuInfo, CpuFeature->ConfigData)) {
> +      SupportedMaskOr (
> +        CpuFeaturesData->InitOrder[ProcessorNumber].FeaturesSupportedMask,
> +        CpuFeature->FeatureMask
> +        );
>      }
> +
>      Entry = Entry->ForwardLink;
>    }
>  }

The functional effect of the change in CollectProcessorData() is too
complex for me to determine, so I'd like to leave the review of this
patch to Ray only.

(1) FWIW, I've attempted to read the BZ carefully, and it seems the
patch doesn't do all things that the BZ suggests:

- The IsCpuFeatureSupported() function is not removed. That could be
correct, but then I think it should be explained in the BZ (i.e. update
the scope).

- Is it asserted somewhere that PcdCpuFeaturesSetting and
PcdCpuFeaturesCapability have equal size?

(2) Independently, please append (or prepend) a cleanup patch to the
series. Namely, the comment block on IsCpuFeatureSetInCpuPcd()
references "PcdCpuFeaturesSupport". It should reference "CpuBitMask"
instead, IMO.

Thanks
Laszlo

> @@ -646,8 +620,6 @@ AnalysisProcessorFeatures (
>        DumpCpuFeature (CpuFeature);
>        Entry = Entry->ForwardLink;
>      }
> -    DEBUG ((DEBUG_INFO, "PcdCpuFeaturesSupport:\n"));
> -    DumpCpuFeatureMask (CpuFeaturesData->SupportPcd);
>      DEBUG ((DEBUG_INFO, "PcdCpuFeaturesCapability:\n"));
>      DumpCpuFeatureMask (CpuFeaturesData->CapabilityPcd);
>      DEBUG ((DEBUG_INFO, "PcdCpuFeaturesSetting:\n"));
> diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeatures.h b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeatures.h
> index 3e0a342fd1..836ed3549c 100644
> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeatures.h
> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeatures.h
> @@ -81,7 +81,6 @@ typedef struct {
>    LIST_ENTRY               FeatureList;
>  
>    CPU_FEATURES_INIT_ORDER  *InitOrder;
> -  UINT8                    *SupportPcd;
>    UINT8                    *CapabilityPcd;
>    UINT8                    *SettingPcd;
>  
> diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> index 3540029079..3e8e899766 100644
> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
> @@ -31,7 +31,7 @@ IsCpuFeatureMatch (
>  {
>    UINTN                 BitMaskSize;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>    if (CompareMem (FirstFeatureMask, SecondFeatureMask, BitMaskSize) == 0) {
>      return TRUE;
>    } else {
> @@ -53,7 +53,7 @@ DumpCpuFeatureMask (
>    UINT8                  *Data8;
>    UINTN                  BitMaskSize;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>    Data8       = (UINT8 *) FeatureMask;
>    for (Index = 0; Index < BitMaskSize; Index++) {
>      DEBUG ((DEBUG_INFO, " %02x ", *Data8++));
> @@ -100,7 +100,7 @@ IsBitMaskMatchCheck (
>    UINT8      *Data1;
>    UINT8      *Data2;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>  
>    Data1 = FeatureMask;
>    Data2 = DependentBitMask;
> @@ -656,7 +656,7 @@ RegisterCpuFeatureWorker (
>    UINTN                      BitMaskSize;
>    BOOLEAN                    FeatureExist;
>  
> -  BitMaskSize     = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize     = PcdGetSize (PcdCpuFeaturesSetting);
>    CpuFeaturesData = GetCpuFeaturesData ();
>    if (CpuFeaturesData->FeaturesCount == 0) {
>      InitializeListHead (&CpuFeaturesData->FeatureList);
> @@ -870,7 +870,7 @@ RegisterCpuFeature (
>    BeforeAll            = FALSE;
>    AfterAll             = FALSE;
>  
> -  BitMaskSize = PcdGetSize (PcdCpuFeaturesSupport);
> +  BitMaskSize = PcdGetSize (PcdCpuFeaturesSetting);
>  
>    VA_START (Marker, InitializeFunc);
>    Feature = VA_ARG (Marker, UINT32);
>